A micromechanical resonator employing multi-vibrator coupling

Abstract

The application discloses a micromechanical resonator adopting multi-vibrator coupling, which comprises at least one group of vibrators, four groups of driving / detecting electrodes corresponding to each group of vibrators, a coupling beam, a supporting beam and an anchor point, wherein the vibrators, the driving / detecting electrodes, the coupling beam, the supporting beam and the anchor point are symmetrically distributed relative to the center of the resonator, the vibrators are connected with the coupling beam, the coupling beam is connected with the supporting beam, the supporting beam is connected with the anchor point, and the vibrators, the coupling beam, the supporting beam and the anchor point jointly form a frame structure, and the driving / detecting electrodes are located on the vibrators, inside the vibrators and / or outside the vibrators. The application adopts multiple vibrators, the vibrators are coupled with each other, one or more vibrators can be used for driving, and the remaining vibrators can be used for detection, so that the driving electrodes and the detecting electrodes are spatially isolated, the coupling of the driving signal to the detecting end is reduced, the driving vibrators and the detecting vibrators are separated, the vibrators can be driven or detected in a differential mode, and the anti-interference capability of the resonator is improved.

Description

Technical Field

[0001] The present invention relates to a micromechanical resonator, in particular to a micromechanical resonator using multi-oscillator coupling. Background Art

[0002] The performance of electronic devices and systems depends on the accuracy and stability of the clock or frequency reference devices they use. Resonators are at the core of these devices. MEMS resonators have broad market demand due to their low power consumption, small size, light weight, low cost, easy integration, high reliability, and strong environmental adaptability.

[0003] With the expansion of application areas and the increasing demand for use, micromechanical resonators are required to be continuously reduced in size, continuously improved in precision, and continuously enhanced in environmental adaptability. There is a need for both extremely low-power, low-frequency resonators for real-time clocks, and high-frequency or ultra-high-frequency resonators for high-precision clocks or high-frequency, high-precision frequency references. Accelerated technological progress, shortened R&D cycles, and reduced R&D costs require a small-sized resonator that can be used for both extremely low-power, low-frequency resonators and high-frequency or ultra-high-frequency resonators, thereby reducing the development cycle and cost of design, process, and supporting circuits.

[0004] Existing resonators mostly adopt single oscillator structures such as tuning fork or ring types, such as patents US8234774B2, US10501310B2, US2018 / 0339898, US7323952B2 and US2005 / 0206479A1. However, on the one hand, they have difficulty in achieving differential detection and have poor anti-interference capabilities; on the other hand, the driving electrodes and the detection electrodes cross in space, and the driving signal is easily coupled to the detection end, which is not conducive to improving the performance of the oscillator; moreover, under the constraint of small size, one structural form cannot take into account the application of extremely low-power low-frequency resonators and high-frequency or ultra-high-frequency resonators.

[0005] Existing resonators using multiple oscillators, such as those disclosed in patents US7750758B2 and US2009 / 0058561A1, employ a structure consisting of two groups of four oscillators. These resonators implement differential drive and differential detection, allowing for spatial decoupling of the drive and detection electrodes. However, these resonators only achieve mutual coupling between two oscillators within each group, without coupling between the two groups. During operation, only one oscillator in each group must be driven, resulting in poor coupling and limited flexibility. Furthermore, each oscillator in these resonators has only one support point, making it difficult to increase support stiffness and hindering further improvements in mechanical properties.

[0006] Patent US2005 / 0206479A1 discloses a resonator using multi-element coupling, which enables mutual coupling between all the elements. However, each element in this resonator has an anchor point, which is not conducive to reducing the resonator's sensitivity to thermal and packaging stress. Furthermore, this resonator is only suitable for disc-shaped elements and cannot be used in low-frequency, extremely low-power applications, such as real-time clocks. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a micromechanical resonator using multi-oscillator coupling. Multiple oscillators are used, and the oscillators are coupled to each other to achieve synchronous resonance of the oscillators. One or more of the oscillators can be used for driving, and the remaining oscillators can be used for detection. This not only increases the flexibility of driving or detecting, but also facilitates the spatial isolation of the driving electrode and the detection electrode, reduces the coupling of the driving signal to the detection end, and is beneficial to improving the performance of the resonator; the driving oscillator and the detection oscillator are separated, which facilitates the use of a differential method to drive or detect the oscillator, thereby improving the anti-interference ability of the resonator.

[0008] To solve the above technical problems, the present invention provides a micromechanical resonator using multi-vibrator coupling, including at least one group of vibrators, each group of vibrators corresponding to four groups of drive / detection electrodes, a group of coupling beams, a group of support beams and an anchor point; the drive / detection electrodes are located on the vibrator, inside the vibrator and / or outside the vibrator, the vibrator is connected to the end of the coupling beam, the middle area of ​​the coupling beam is connected to one end of the support beam, and the other end of the support beam is connected to the anchor point. The vibrator, coupling beam, support beam and anchor point together form a frame structure, which is fixed by the anchor point. The vibrator, drive / detection electrodes, coupling beam, support beam and anchor point are symmetrically distributed relative to the center of the resonator.

[0009] The micromechanical resonator of the present invention uses multiple oscillators, and each oscillator is coupled to each other to achieve synchronous resonance of each oscillator. It can also use separate driving oscillators and detection oscillators, using one or more oscillators for driving and the remaining oscillators for detection, to achieve spatial isolation of the driving electrode and the detection electrode, reducing the coupling of the driving signal to the detection end, while facilitating the use of differential driving or detection of the oscillators to improve the anti-interference ability of the resonator. The middle of the resonator is supported by multiple support beams, and the anchor point is set at the intersection of the support beams, which is also the center area of ​​the resonator to reduce sensitivity to thermal stress and packaging stress. The resonator adopts a frame structure as a whole, which can increase the support stiffness and thus improve the mechanical environment adaptability of the resonator. The present invention utilizes the elliptical vibration mode or radial expansion / compression mode of the oscillator to achieve resonance from low frequency to ultra-high frequency under small size constraints and the same or similar process. The area of ​​the resonator can be less than 500×500 microns, and the operating frequency of the resonator can cover 100kHz to 10GHz.

[0010] Preferably, the coupling beam is a "I" shaped coupling beam, which is advantageous to increase the frequency difference between the working mode and the non-working mode, thereby improving the performance of the resonator.

[0011] Preferably, a coupling beam neck is arranged at the joint of the vibrator and the coupling beam, a support beam neck is arranged at the joint of the coupling beam and the support beam, and an anchor slot is arranged at the joint of the support beam and the anchor, which can optimize the coupling between the vibrators or reduce the energy loss of the vibrators, thereby improving the quality factor of the resonator and the performance of the resonator.

[0012] Preferably, the modal node of the resonator is arranged at the joint of the coupling beam and the support beam, which is advantageous to improve the quality factor of the resonator.

[0013] As an embodiment of the present application, the vibrator is in a circular ring shape, and each group of driving / detecting electrodes includes four inner electrodes inside the vibrator and four outer electrodes outside the vibrator.

[0014] As an embodiment of the present application, the vibrator is in a circular ring shape, and each group of driving / detecting electrodes includes four upper electrodes on the vibrator, the material of the upper electrodes is piezoelectric material, and the vibrator is driven or detected in a piezoelectric manner.

[0015] As an embodiment of the present application, the vibrator is in a circular ring shape, and each group of driving / detecting electrodes includes four inner electrodes inside the vibrator, four outer electrodes outside the vibrator, and four upper electrodes on the vibrator, the material of the upper electrodes is piezoelectric material, and the vibrator is driven or detected in a piezoelectric or capacitive manner, thereby increasing the electromechanical coupling coefficient of the vibrator and improving the performance of the resonator.

[0016] As an embodiment of the present application, the working mode of the vibrator is a radial expansion mode, and during the working, the four vibrators are simultaneously expanded or reduced in the radial direction, and correspondingly, the inner electrodes inside the vibrator are connected together to form an integrated inner electrode, and the outer electrodes outside the vibrator are connected together to form an integrated outer electrode, and when the vibrator works in the radial expansion mode, the working frequency of the vibrator is relatively high, which can reach MHz, and the vibrator can be used in high-frequency and high-precision application occasions.

[0017] As an embodiment of the present application, the vibrator is in a circular disc or square disc shape, and each group of driving / detecting electrodes includes four outer electrodes outside the vibrator, and when the vibrator is in a circular disc shape, the modal frequency can reach 10 GHz, and the vibrator can be used in an ultrahigh frequency occasion.

[0018] As an embodiment of the present invention, the vibrator is in the shape of a circular disk or a square disk, and each group of driving / detecting electrodes includes four external electrodes located outside the vibrator and four upper electrodes located above the vibrator. The upper electrodes are made of piezoelectric material, and the vibrator is driven or detected by piezoelectric or capacitive methods at the same time, which can increase the electromechanical coupling coefficient of the vibrator, thereby improving the performance of the resonator.

[0019] The present invention has the following advantages due to the adoption of the above technical solution:

[0020] 1. Due to the use of a multi-oscillator structure and the mutual coupling between the oscillators to achieve synchronous resonance of the oscillators, one or more oscillators can be used for driving, and the remaining oscillators can be used for detection. This not only increases the flexibility of driving or detection, but also facilitates the spatial isolation of the driving electrode and the detection electrode, reduces the coupling of the driving signal to the detection end, and is conducive to improving the performance of the resonator.

[0021] 2. The driving oscillator and the detecting oscillator are separated to facilitate driving or detecting the oscillator in a differential manner, thereby improving the anti-interference ability of the resonator.

[0022] 3. The resonator adopts a frame structure as a whole, which can improve the support stiffness and thus improve the resonator's adaptability to the mechanical environment.

[0023] 4. The use of "I"-shaped coupling beams between adjacent oscillators is beneficial to increasing the frequency difference between the working mode and the non-working mode, thereby improving the performance of the resonator.

[0024] 5. The resonator is supported by multiple support beams in the middle, and the anchor point is set at the intersection of the support beams, which is also the center area of ​​the resonator, which helps to reduce the sensitivity to thermal stress and packaging stress.

[0025] 6. A coupling beam neck is provided at the connection between the vibrator and the coupling beam, a support beam neck is provided at the connection between the coupling beam and the support beam, and an anchor point groove is provided at the connection between the support beam and the anchor point. This can optimize the coupling between the vibrators or reduce the energy loss of the vibrators, improve the quality factor of the resonator, and thus improve the performance of the resonator.

[0026] 7. The node of the resonator is set at the junction of the "I" coupling beam and the support beam, which is conducive to further reducing the energy loss of the oscillator, improving the quality factor of the resonator, and thus improving the performance of the resonator.

[0027] 8. The elliptical vibration mode or radial expansion / compression mode of the vibrator can be used to achieve resonance from low frequency to ultra-high frequency under small size constraints. The area of ​​the resonator can be less than 500×500 microns, and the operating frequency of the resonator can cover 100kHz~10GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0029] Figure 2 It is a schematic structural diagram of an oscillator and a group of driving / detecting electrodes of the present invention.

[0030] Figure 3 2 is a schematic diagram of the working mode of the first embodiment.

[0031] Figure 4 FIG. 1 is a schematic structural diagram of a vibrator and a group of driving / detecting electrodes according to the second embodiment.

[0032] Figure 5 FIG. 1 is a schematic structural diagram of a vibrator and a group of driving / detecting electrodes according to the third embodiment.

[0033] Figure 6 2 is a schematic diagram of the working mode of the fourth embodiment.

[0034] Figure 7 FIG. 1 is a schematic structural diagram of a vibrator and a group of driving / detecting electrodes according to the fourth embodiment.

[0035] Figure 8 FIG. 1 is a schematic structural diagram of a vibrator and a group of driving / detecting electrodes according to the fifth embodiment.

[0036] Figure 9 It is a schematic diagram of the overall structure of Example 6.

[0037] Figure 10 Schematic diagram of the working mode of the sixth embodiment.

[0038] Figure 11 It is a schematic diagram of the overall structure of embodiment seven.

[0039] Figure 12 FIG. 1 is a schematic structural diagram of a vibrator and a group of driving / detecting electrodes according to the seventh embodiment.

[0040] Figure 13 FIG. 1 is a schematic structural diagram of a vibrator and a group of driving / detecting electrodes according to the eighth embodiment.

[0041] Figure 14 FIG. 1 is a schematic structural diagram of a vibrator and a group of driving / detecting electrodes according to the ninth embodiment.

[0042] Figure 15 It is a schematic diagram of the overall structure of the tenth embodiment.

[0043] Figure 16 This is a 1 / 4 structural diagram of the tenth embodiment. DETAILED DESCRIPTION

[0044] The present invention will be further described below with reference to the accompanying drawings and examples.

[0045] Example 1

[0046] A micromechanical resonator using multi-vibrator coupling, such as Figure 1 As shown in FIG. 3 , the present invention comprises a group of vibrators, four groups of driving / detecting electrodes 120, a group of coupling beams, a group of supporting beams, and a group of anchor points 150. A group of vibrators comprises four vibrators 110a, 110b, 110c, and 110d. The four vibrators 110a, 110b, 110c, and 110d are all ring-shaped. Each group of driving / detecting electrodes 120 comprises four outer electrodes 120a, 120b, 120c, and 120d located outside the vibrator 110 and four inner electrodes 120e, 120f, 120g, and 120h located inside the vibrator 110. Figure 2 As shown, each set of coupling beams includes four "I"-shaped coupling beams 130a, 130b, 130c, and 130d, and each set of support beams includes four support beams 140a, 140b, 140c, and 140d. Vibrator 110a is connected to one end of both coupling beams 130a and 130d, vibrator 110b is connected to the other end of coupling beam 130a and one end of 130b, vibrator 110c is connected to the other end of coupling beam 130b and one end of 130c, and vibrator 110d is connected to the other end of coupling beam 130c and the other end of 130d. The middle portions of the coupling beams 130a, 130b, 130c, and 130d are connected to one end of the support beams 140a, 140b, 140c, and 140d, respectively. The other ends of the support beams 140a, 140b, 140c, and 140d are connected to the anchor 150. The vibrator 110, the coupling beams, the support beams, and the anchor 150 together form a frame-type structure 1, which is fixed by the anchor 150. The vibrator 110, the driving / detecting electrode 120, the coupling beams, the support beams, and the anchor 150 are symmetrically distributed relative to the center of the resonator.

[0047] When in use, a portion of the electrodes is used for driving, and the other portion of the electrodes is used for detection. The vibrators 110a, 110b, 110c, and 110d are driven according to the Figure 3 The elliptical vibration mode shown in the figure. When the elliptical vibration mode is used, the frequency of the oscillator is low and the required driving power is small, which is suitable for extremely low power applications such as real-time clocks.

[0048] Since the four vibrators 110a, 110b, 110c, and 110d are coupled to each other, the driving vibrator and the detecting vibrator can be separated during operation, that is, one to three vibrators are driven, and the remaining three are detected by one vibrator. This facilitates the spatial isolation of the driving electrode and the detecting electrode, reduces the coupling of the driving signal to the detection end, is beneficial to improving the performance of the resonator, and also facilitates the use of a differential method to drive or detect the vibrator, thereby improving the resonator's anti-interference ability.

[0049] Example 2

[0050] The difference between this embodiment and the first embodiment is that the structure of the driving / detecting electrode 120 is different. Figure 4 As shown, the driving / detecting electrode 120 of this embodiment includes only four upper electrodes 120i, 120j, 120k, and 120l located on the vibrator 110. The upper electrodes 120i, 120j, 120k, and 120l are made of piezoelectric materials, and the vibrator 110 uses a piezoelectric method for driving or detecting.

[0051] Example 3

[0052] The difference between this embodiment and the first embodiment is that the structure of the driving / detecting electrode 120 is different. Figure 5 As shown, the driving / detecting electrode 120 of this embodiment adds four upper electrodes 120i, 120j, 120k, and 120l located on the vibrator 110. The added upper electrodes 120i, 120j, 120k, and 120l are made of piezoelectric related materials. The vibrator 110 can be driven or detected by piezoelectric or capacitance at the same time, which increases the electromechanical coupling coefficient of the vibrator and thus improves the resonator performance.

[0053] Example 4

[0054] The difference between this embodiment and the first embodiment is that the working mode of the vibrator 110 is the radial expansion mode. Figure 6 As shown, during operation, the four vibrators 110a, 110b, 110c, and 110d simultaneously expand radially (110a', 110b', 110c', and 110d') or shrink (110a", 110b", 110c", and 110d"). Accordingly, the internal electrodes of the vibrator 110 are connected together to form an internal electrode 120m, and the external electrodes outside the vibrator 110 are connected together to form an external electrode 120n. Figure 7 When operating in radial expansion mode, the vibrator 110 has a relatively high operating frequency, which can cover MHz, and is suitable for high-frequency and high-precision applications.

[0055] Example 5

[0056] The only difference between this embodiment and the fourth embodiment is that the driving / detecting electrode 120 of this embodiment is increased by an upper electrode 120p on the vibrator 110. Figure 8 As shown, the upper electrode 120p is made of piezoelectric related materials, and the vibrator 110 can be driven or detected by piezoelectric or capacitance at the same time, which increases the electromechanical coupling coefficient of the vibrator 110 and thus improves the resonator performance.

[0057] Example 6

[0058] The difference between this embodiment and the first embodiment is that the four vibrators 110a, 110b, 110c, and 110d are all disc-shaped, and each set of driving / detecting electrodes 120 includes four external electrodes 120a, 120b, 120c, and 120d located outside the vibrator 110. Figure 9 As shown, the vibration shape of the preferred working mode of the oscillator is as follows Figure 10 As shown, when the vibrator adopts a disk type, the modal frequency can reach 10GHz, which is used in ultra-high frequency applications.

[0059] Example 7

[0060] The only difference between this embodiment and the sixth embodiment is that the driving / detecting electrode 120 of this embodiment is increased by upper electrodes 120r, 120s, 120t, and 120u on the vibrator 110. Figure 11 、 Figure 12 As shown, the upper electrodes 120r, 120s, 120t, and 120u are made of piezoelectric related materials, and the vibrator 110 can be driven or detected by piezoelectric or capacitance at the same time, which increases the electromechanical coupling coefficient of the vibrator 110 and thus improves the resonator performance.

[0061] Example 8

[0062] The only difference between this embodiment and the sixth embodiment is that the vibrator 110 is a square disk. Figure 13 shown.

[0063] Embodiment 9

[0064] The only difference between this embodiment and the seventh embodiment is that the vibrator 110 is a square disk. Figure 14 shown.

[0065] Example 10

[0066] The only difference between this embodiment and the first, second, third, fourth, fifth, sixth or seventh embodiments is that a coupling beam neck 112 is provided at the connection between the vibrator 110 and the "I" coupling beam 130, a support beam neck 132 is provided at the connection between the "I" coupling beam 130 and the support beam 140, and an anchor groove 152 is provided at the connection between the support beam 140 and the anchor point 150. Figure 15 、 Figure 16 As shown, the coupling between the oscillators is optimized or the energy loss of the oscillators is reduced, thereby improving the quality factor of the resonator and thus improving the performance of the resonator.

[0067] The above is only the best embodiment of the present invention. It should be noted that, for those skilled in the art, without departing from the principles of the present invention, several modifications or equivalent substitutions can be made to the technical solution of the present invention, which can still achieve the technical effects of the present invention and should also be considered to fall within the scope of protection of the present invention.

Claims

1. A micromechanical resonator employing multi-vibrator coupling, comprising at least one group of vibrators, each group of vibrators corresponding to four groups of drive / detection electrodes, a group of coupling beams, a group of support beams, and an anchor point; the drive / detection electrodes being located on, within, and / or outside the vibrators; the vibrators being connected to the ends of the coupling beams; the middle region of the coupling beams being connected to one end of the support beam; and the other end of the support beam being connected to the anchor point; the vibrators, coupling beams, support beams, and anchor point together forming a frame structure, which is secured by the anchor point; and the vibrators, drive / detection electrodes, coupling beams, support beams, and anchor point being symmetrically distributed relative to the center of the resonator; Its characteristics are: A coupling beam neck is provided at the connection between the vibrator and the coupling beam, a supporting beam neck is provided at the connection between the coupling beam and the supporting beam, and an anchor point groove is provided at the connection between the supporting beam and the anchor point.

2. The micromechanical resonator using multi-vibrator coupling according to claim 1, characterized in that: The vibrator is in a ring shape, and each group of driving / detecting electrodes includes four inner electrodes located inside the vibrator and four outer electrodes located outside the vibrator.

3. The micromechanical resonator using multi-vibrator coupling according to claim 1, characterized in that: The vibrator is in a ring shape. Each group of driving / detecting electrodes includes four upper electrodes located on the vibrator. The material of the upper electrodes is piezoelectric material. The vibrator is driven or detected in a piezoelectric manner.

4. The micromechanical resonator using multi-vibrator coupling according to claim 1, characterized in that: The vibrator is ring-shaped, and each set of driving / detecting electrodes includes four inner electrodes located inside the vibrator, four outer electrodes located outside the vibrator, and four upper electrodes located on the vibrator. The upper electrodes are made of piezoelectric material, and the vibrator is driven or detected by piezoelectric or capacitive methods at the same time.

5. The micromechanical resonator using multi-vibrator coupling according to claim 2 or 4, characterized in that: The inner electrodes are connected together to form an inner electrode, and the outer electrodes are connected together to form an outer electrode.

6. The multi-element coupled micromechanical resonator according to claim 1, wherein: The vibrator is in the shape of a circular disk or a square disk, and each group of driving / detecting electrodes includes four external electrodes located outside the vibrator.

7. The micromechanical resonator using multi-vibrator coupling according to claim 1, characterized in that: The vibrator is in the shape of a circular disk or a square disk. Each set of driving / detecting electrodes includes four outer electrodes located outside the vibrator and four upper electrodes located above the vibrator. The upper electrodes are made of piezoelectric material. The vibrator is driven or detected by piezoelectric or capacitive means at the same time.

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