A tuning fork type piezoelectric vibration piece and an oscillator

Abstract

The embodiment of the present application relates to a tuning fork type piezoelectric vibration piece and an oscillator, which are used to improve Q value. The tuning fork type piezoelectric vibration piece comprises a base and two vibration arm parts extending from one end of the base, the two vibration arm parts are symmetrically arranged, and the polarities of the driving electrodes at corresponding positions are opposite; for each vibration arm part: a driving groove is arranged on the first main surface of the vibration arm part, and an inner wall driving electrode is arranged on the inner wall of the driving groove; a side wall driving electrode is arranged on the side wall of the vibration arm part; at least one planar driving electrode is arranged on the second main surface of the vibration arm part corresponding to the position of the driving groove along the width direction of the vibration arm part; and the first main surface and the second main surface are two opposite surfaces.

Description

Technical Field

[0001] This application relates to the field of piezoelectric vibration elements, and in particular to a tuning fork type piezoelectric vibrator and oscillator. Background Technology

[0002] Tuning fork piezoelectric resonators have excellent frequency-temperature characteristics and are widely used as frequency reference sources in various electronic devices. However, with the miniaturization of devices, the temperature difference generated by the bending vibration of tuning fork piezoelectric resonators is difficult to eliminate, resulting in a significant decrease in the Q value. Summary of the Invention

[0003] This application provides a tuning fork type piezoelectric vibrator and an oscillator to improve the Q value.

[0004] In a first aspect, embodiments of this application provide a tuning fork type piezoelectric vibrator, including a base and two vibrating arms extending from one end of the base. The two vibrating arms are symmetrically arranged, and the polarities of the driving electrodes at corresponding positions are opposite. For each vibrating arm:

[0005] The first main surface of the vibrating arm is provided with a drive groove, and the inner wall of the drive groove is provided with an inner wall drive electrode.

[0006] The sidewall of the vibrating arm is provided with a sidewall driving electrode;

[0007] Along the width direction of the vibrating arm, at least one planar driving electrode is provided on the second main surface of the vibrating arm corresponding to the position of the driving groove;

[0008] The first main surface and the second main surface are two opposite surfaces.

[0009] In one possible implementation, the drive groove is an integral groove, and the depth of the drive groove is no more than 80% of the thickness of the vibrating arm.

[0010] In one possible implementation, a partition beam is provided at the bottom of the drive groove along the length of the vibrating arm to divide the drive groove into two grooves of the same width, and the depth of the drive groove is no more than 85% of the thickness of the vibrating arm.

[0011] In one possible implementation, the length of the drive groove accounts for 40%-70% of the length of the vibrating arm, and the width of the drive groove accounts for 35%-65% of the width of the vibrating arm.

[0012] In one possible implementation, the length of the planar driving electrode is the same as the length of the driving groove.

[0013] In one possible implementation, the second main surface of the vibrating arm is provided with three planar driving electrodes, the polarities of the three planar driving electrodes changing alternately;

[0014] The polarity of the side wall drive electrode of the vibrating arm is the same as that of the two planar drive electrodes on both sides of the three planar drive electrodes on the second main surface of the vibrating arm, and opposite to that of the inner wall drive electrode of the drive groove on the first main surface of the vibrating arm.

[0015] In one possible implementation, the side wall driving electrodes of the vibrating arm and the two side planar driving electrodes of the three planar driving electrodes on the second main surface of the vibrating arm are non-segmented electrodes, and the middle planar driving electrode of the three planar driving electrodes on the second main surface of the vibrating arm is a rectangular electrode.

[0016] In one possible implementation, the first main surface of the vibrating arm is further provided with a small groove, the small groove being located at the root of the vibrating arm near the base, and the depth of the small groove being the same as the depth of the drive groove.

[0017] The inner wall of the small groove is provided with an inner wall driving electrode, and the polarity of the inner wall driving electrode of the small groove is the same as that of the inner wall driving electrode of the driving groove.

[0018] In one possible implementation, the base is provided with a plurality of width reduction portions that are completely through in thickness near the vibrating arm portion, and the width reduction portions on both sides of the base are symmetrically arranged.

[0019] The width reduction portions on each side of the base are arranged in a serrated parallel pattern with equal spacing.

[0020] Secondly, embodiments of this application provide an oscillator, including the tuning fork type piezoelectric vibrator described in the first aspect.

[0021] When using the tuning fork piezoelectric vibrator provided in the embodiments of this application, the heat transfer distance from the compressed surface to the elongated surface becomes longer during bending vibration, that is, the heat conduction path becomes longer, which can reduce the energy dissipation caused by thermoelastic damping and thus improve the Q value.

[0022] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0023] Figure 1 This is a three-dimensional schematic diagram of the tuning fork piezoelectric vibrator provided in Embodiment 1 of this application;

[0024] Figure 2 This is a schematic diagram of the cross-section of the vibrating arm of the tuning fork piezoelectric vibrator provided in Embodiment 1 of this application;

[0025] Figure 3 This is a schematic diagram of the heat conduction path of the tuning fork piezoelectric vibrator provided in Embodiment 1 of this application;

[0026] Figure 4 This is a schematic diagram of the first main surface of the tuning fork piezoelectric vibrator provided in Embodiment 1 of this application;

[0027] Figure 5 This is a schematic diagram of the second main surface of the tuning fork piezoelectric vibrator provided in Embodiment 1 of this application;

[0028] Figure 6 This is a schematic diagram of the first main surface of the tuning fork piezoelectric vibrator provided in Embodiment 2 of this application;

[0029] Figure 7 This is a schematic diagram of the cross-section of the vibrating arm of the tuning fork piezoelectric vibrator provided in Embodiment 2 of this application;

[0030] Figure 8 This is a schematic diagram of the second main surface of the tuning fork piezoelectric vibrator provided in Embodiment 3 of this application;

[0031] Attached image labels:

[0032] 10: Tuning fork type piezoelectric vibrator;

[0033] 11: Base; 12a, 12b: Width reduction portion;

[0034] 11a, 11b: Driving electrodes of the base; 11c, 11d: Electrode patterns;

[0035] 20a, 20b: Vibrating arm; 21a, 21b: Small groove; 22a, 22b: Drive groove in Example 1; 221a, 222a, 221b, 222b: Groove of drive groove in Example 2;

[0036] 23a, 23b: Inner wall driving electrodes of the driving groove in Example 1; 261a, 271a, 261b, 271b: Inner wall driving electrodes of the driving groove in Example 2; 241, 251: The middle planar driving electrode among the three planar driving electrodes; 242, 243, 252, 253: Side wall driving electrodes of the vibrating arm.

[0037] 31, 41: Heavy-duty parts;

[0038] 31c, 41c: Driving electrodes of the weight-bearing section. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this application. Obviously, the described embodiments are only some embodiments of the technical solutions of this application, and not all embodiments. Based on the embodiments recorded in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the technical solutions of this application.

[0040] This application provides a tuning fork type piezoelectric vibrating plate, such as Figure 1-8 As shown, it includes a base and two identical vibrating arms extending from one end of the base. The two vibrating arms are arranged in parallel and symmetrically, and the polarities of the driving electrodes at corresponding positions are opposite. Therefore, the electric driving force generated is in opposite directions, and the two vibrating arms repeatedly approach or move away from each other.

[0041] For each vibrating arm:

[0042] The first main surface of the vibrating arm is provided with a drive groove, and the inner wall of the drive groove is provided with an inner wall drive electrode.

[0043] The sidewall of the vibrating arm is provided with a sidewall drive electrode;

[0044] Along the width direction of the vibrating arm, at least one planar driving electrode is provided on the second main surface of the vibrating arm corresponding to the position of the driving groove.

[0045] Among them, the first principal face and the second principal face are two opposite faces.

[0046] When using the tuning fork-type piezoelectric vibrator provided in the embodiments of this application, the heat transfer distance from the compressed surface to the elongated surface becomes longer during bending vibration, that is, the heat conduction path becomes longer, which can reduce the energy dissipation caused by thermoelastic damping, thereby improving the Q value and contributing to the miniaturization of the device.

[0047] Furthermore, currently, hydrofluoric acid etching solution is commonly used for wet etching to obtain the desired tuning fork piezoelectric vibrator. Using the tuning fork piezoelectric vibrator provided in the embodiments of this application can reduce the number of etching grooves and simplify the process.

[0048] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application. Furthermore, the embodiments and features in the embodiments of this application can be combined with each other without conflict.

[0049] Example 1:

[0050] The tuning fork-type piezoelectric vibrating sheet provided in Embodiment 1 of this application is as follows: Figure 1-5 As shown.

[0051] In this embodiment, as Figure 1 As shown, the drive groove on the first main surface of the vibrating arm is a single integral groove, i.e. Figure 2 As shown, the cross-sectional shape of the drive groove on the vibrating arm is U-shaped.

[0052] By setting a U-shaped drive groove, when the vibrating arm undergoes bending vibration between the first and second main surfaces, the heat conduction path is as follows: Figure 3 As shown, direct heat transfer between the compressed and elongated surfaces can be blocked, increasing the heat transfer distance, reducing thermoelastic damping, and effectively improving the electric field efficiency.

[0053] In actual implementation, in this embodiment, the depth of the driving groove accounts for no more than 80% of the thickness of the vibrating arm, the length accounts for 40%-70% of the length of the vibrating arm, and the width accounts for 35%-65% of the width of the vibrating arm. This can generate a sufficiently large electric field driving force to drive the vibrating arm to perform alternating bending vibration, while preventing the crystal impedance value from being too large and affecting the device performance.

[0054] like Figure 2 As shown, the inner wall of the drive groove is provided with an inner wall drive electrode.

[0055] In this embodiment, as Figure 5 As shown, along the width direction of the vibrating arm, three planar driving electrodes are arranged at the position of the second main surface of the vibrating arm corresponding to the driving groove. Among the three planar driving electrodes, the two planar driving electrodes on both sides are non-segmented electrodes, and the planar driving electrode in the middle is a rectangular electrode.

[0056] In actual implementation, the polarities of the three planar driving electrodes change alternately, that is, the polarities of the two planar driving electrodes on both sides are opposite to the polarities of the middle planar driving electrode.

[0057] Furthermore, the polarity of the planar driving electrodes on both sides is the same as the polarity of the side wall driving electrodes of the vibrating arm; the polarity of the planar driving electrode in the middle is the same as the polarity of the inner wall driving electrode of the driving groove on the first main surface.

[0058] Furthermore, the sidewall drive electrodes of the vibrating arm are also non-segmented electrodes, such as... Figure 2 As shown, the planar driving electrodes on both sides can be integrated with the corresponding sidewall driving electrodes.

[0059] By setting up three planar driving electrodes, the electric field efficiency can be further improved, and a better driving effect can be produced when the same voltage is applied.

[0060] Preferably, the length of the planar driving electrode is the same as the length of the driving slot. At this length, the resonant frequency of the planar driving electrode is closest to that of the driving slot, which can realize the coupling of the two electric field driving forces.

[0061] Preferably, among the three planar driving electrodes, the total area of ​​the two planar driving electrodes is the same as the area of ​​the middle planar driving electrode, and the spacing between the two planar driving electrodes and the middle planar driving electrode is the same.

[0062] In this embodiment, as Figure 1 As shown, the first main surface of the vibrating arm is also provided with a small groove. The small groove is located at the root of the vibrating arm near the base. The rear side of the small groove is the same distance from the root of the vibrating arm to the end of the base.

[0063] like Figure 4 As shown, the inner wall of the small tank is provided with an inner wall driving electrode, and the polarity of the inner wall driving electrode of the small tank is the same as that of the inner wall driving electrode of the driving tank.

[0064] By setting up small grooves, direct heat transfer is blocked, the heat conduction path is increased, and the Q value is improved. Moreover, the small grooves also effectively reduce the local stress caused by bending at the root of the vibrating arm, preventing the vibrating arm from breaking due to stress.

[0065] It should be noted that in this embodiment, the small groove is located on the first main surface; in other embodiments, the small groove may also be located on the second main surface, and this application does not make specific limitations.

[0066] Preferably, the miniature groove is located on the first main surface of the vibrating arm, and the depth of the miniature groove is the same as the depth of the drive groove, which can further reduce the number of etching operations and simplify the process.

[0067] In this embodiment, as Figure 1 As shown, the base near the vibrating arm has multiple width reduction sections that are completely through in thickness, and the width reduction sections on both sides of the base are symmetrically arranged.

[0068] In actual implementation, the width reduction portions on each side of the base are arranged in parallel in a sawtooth pattern with equal spacing.

[0069] By setting a width reduction section, the displacement changes caused by vibration are difficult to be transmitted from the vibrating arm to the base, and energy transfer is intercepted, which can effectively reduce vibration leakage from the vibrating arm to the base and further improve the Q value.

[0070] It should be noted that in this embodiment, there can be three width reduction portions on each side of the base; in other embodiments, there can be two, four, or other numbers of width reduction portions on each side of the base, and this application does not make specific limitations.

[0071] like Figure 4 , Figure 5As shown, driving electrodes are also provided on both sides of the base, and the polarity of the driving electrode on each side of the base is opposite to that of the driving electrode on the inner wall of the driving groove of the first main surface of the corresponding vibrating arm.

[0072] In this embodiment, as Figure 1 As shown, the tuning fork type piezoelectric vibrator also includes two identical weighting parts located at the ends of the two vibrating arms. The two weighting parts are symmetrically arranged, and the polarities of the driving electrodes at corresponding positions are opposite.

[0073] In actual implementation, the width of the weight-applying part is slightly larger than the width of the vibrating arm. A width transition area is provided near the vibrating arm of the weight-applying part, and its shape is a straight line connection.

[0074] By setting up a weighting element, the resonant frequency of the vibrating plate can be effectively reduced, and coarse adjustment of the resonant frequency can be achieved.

[0075] Preferably, the end of the weighting part is provided with a metal of a preset thickness, which can achieve fine adjustment of the resonant frequency.

[0076] like Figure 4 As shown, at least one of the first main surface and the second main surface of the weight-applying part is provided with a driving electrode, and the polarity of the driving electrode of the weight-applying part is opposite to the polarity of the driving electrode on the inner wall of the driving groove of the first main surface of the corresponding vibrating arm part.

[0077] In this embodiment, each driving electrode can be made of a metal with good conductivity. The electrodes are attached to the piezoelectric vibrating sheet by sputtering, and the thickness is usually 50nm-200nm.

[0078] The electrode polarity of the first main surface of the tuning fork-type piezoelectric vibrator provided in Embodiment 1 of this application is as follows: Figure 4 As shown, the electrode polarity of the second principal surface is as follows: Figure 5 As shown, different patterns represent different electrode polarities.

[0079] For the first polarity, such as Figure 4 As shown, the driving electrode 11a of the base 11 is connected to the inner wall driving electrode of the small groove 21b and the inner wall driving electrode 23b of the driving groove 22b of the vibrating arm 20b through the electrode pattern 11c. Simultaneously, the driving electrode 11a of the base 11 is connected to the driving electrode 31c of the weighting part 31 through the side wall driving electrode 252 of the vibrating arm 20a. At the same time, the driving electrode 31c of the weighting part 31 is connected to the side wall driving electrode 253 of the vibrating arm 20a. Meanwhile, as... Figure 5 As shown, the driving electrode 11a of the base 11 is also connected to the planar driving electrode 251 in the middle of the second main surface of the vibrating arm portion 20b through the electrode pattern 11d.

[0080] Correspondingly, for the second type of polarity, such as Figure 4As shown, the driving electrode 11b of the base 11 is connected to the driving electrode 41c of the weighting part 41 via the side wall driving electrode 242 of the vibrating arm 20b. Simultaneously, the driving electrode 41c of the weighting part 41 is connected to the inner wall driving electrode of the small groove 21a and the inner wall driving electrode 23a of the driving groove 22a of the vibrating arm 20a via the side wall driving electrode 243 of the vibrating arm 20b. Meanwhile, as... Figure 5 As shown, the side wall drive electrode 243 of the vibrating arm 20b is connected to the planar drive electrode 241 in the middle of the second main surface.

[0081] Example 2:

[0082] The tuning fork-type piezoelectric vibrating sheet provided in Embodiment 2 of this application is as follows: Figure 6-7 As shown.

[0083] In this embodiment, as Figure 6 As shown, along the length of the vibrating arm, a partition beam is provided at the bottom of the drive groove on the first main surface of the vibrating arm, dividing the drive groove into two recesses. Preferably, the width, length, and depth of the two recesses are exactly the same, i.e., as shown in the figure. Figure 7 As shown, the cross-sectional shape of the drive groove on the vibrating arm is ш-shaped.

[0084] In actual implementation, in this embodiment, the depth of the drive groove accounts for no more than 85% of the thickness of the vibrating arm, the length of the drive groove accounts for 40%-70% of the length of the vibrating arm, and the width of the drive groove accounts for 35%-65% of the width of the vibrating arm.

[0085] like Figure 7 As shown, the inner wall of the drive groove is provided with an inner wall drive electrode, while the partition beam inside the drive groove is not provided with a drive electrode.

[0086] Compared to Example 1, by setting a ш-shaped drive groove, the stiffness of the vibrating arm can be enhanced, preventing breakage.

[0087] The specific implementation of other parts of the tuning fork piezoelectric vibrator provided in Embodiment 2 of this application can be found in the aforementioned Embodiment 1, and will not be repeated here.

[0088] It should be noted that in other embodiments of this application, the drive groove on the first main surface of the vibrating arm may also be in other forms, which will not be described in detail here.

[0089] Example 3:

[0090] The tuning fork-type piezoelectric vibrating sheet provided in Embodiment 3 of this application is as follows: Figure 8 As shown.

[0091] In this embodiment, along the width direction of the vibrating arm, three planar driving electrodes are provided at the position of the second main surface of the vibrating arm corresponding to the driving groove. Among the three planar driving electrodes, the two planar driving electrodes on both sides are segmented electrodes, and the planar driving electrode in the middle is a sawtooth electrode.

[0092] In actual implementation, the polarities of the three planar driving electrodes change alternately, that is, the polarities of the two planar driving electrodes on both sides are opposite to the polarities of the middle planar driving electrode.

[0093] Furthermore, the polarity of the planar driving electrodes on both sides is the same as the polarity of the side wall driving electrodes of the vibrating arm; the polarity of the planar driving electrode in the middle is the same as the polarity of the inner wall driving electrode of the driving groove on the first main surface.

[0094] Furthermore, the sidewall drive electrodes of the vibrating arm are also segmented electrodes, and the segmented electrodes are connected by an electrode pattern; the corresponding segmented electrodes of the planar drive electrodes on both sides and the sidewall drive electrodes of the vibrating arm are a whole.

[0095] In actual implementation, the multi-segmented electrode is a three-segmented electrode, and the sawtooth electrode has three serrations, which correspond one-to-one with the three-segmented electrode.

[0096] It should be noted that in this embodiment, the multi-segmented electrode can be a three-segmented electrode; in other embodiments, the multi-segmented electrode can be a two-segmented electrode, a four-segmented electrode, or other number of segmented electrodes, and this application does not make specific limitations.

[0097] The specific implementation of other parts of the tuning fork piezoelectric vibrator provided in Embodiment 3 of this application can be found in the aforementioned Embodiment 1, and will not be repeated here.

[0098] It should be noted that in other embodiments of this application, the planar drive electrodes disposed at the position of the drive groove corresponding to the second main surface of the vibrating arm can also be in other forms; for example, two planar drive electrodes, in which case the polarity of the two planar drive electrodes can be the same and opposite to the polarity of the side wall drive electrodes of the vibrating arm; or, for example, four or more planar drive electrodes, in which case the number of planar drive electrodes is large, and the multiple planar drive electrodes located in the middle can be configured to have the same polarity and opposite to the polarity of the planar drive electrodes on both sides, and the same polarity as the side wall drive electrodes of the vibrating arm.

[0099] This application also provides an oscillator, including the tuning fork-type piezoelectric vibrator provided in the foregoing embodiments. The piezoelectric vibrator is housed within the internal space of a package and vacuum-sealed, providing a certain degree of airtightness. The oscillator provided in this application provides good performance.

[0100] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0101] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A tuning fork type piezoelectric vibration piece, characterized by, The vibration arm part comprises a base and two vibration arm parts extending from one end of the base, the two vibration arm parts are symmetrically arranged, and the polarities of the driving electrodes at corresponding positions are opposite; for each vibration arm part: The first main surface of the vibration arm part is provided with a driving groove, and the inner wall of the driving groove is provided with an inner wall driving electrode; The side wall of the vibration arm part is provided with a side wall driving electrode; the side wall driving electrode is a three-section segmented electrode, and the segmented electrodes are connected through an electrode pattern; Along the width direction of the vibration arm part, the second main surface of the vibration arm part is provided with three planar driving electrodes at positions corresponding to the driving grooves; among the three planar driving electrodes, the planar driving electrodes on the two sides are three-section segmented electrodes, the segmented electrodes of the planar driving electrodes on the two sides correspond to the segmented electrodes of the side wall driving electrode one by one, and the corresponding segmented electrodes are an integral whole, and the segmented electrodes of the planar driving electrodes on the two sides are connected through the electrode pattern of the side wall driving electrode; among the three planar driving electrodes, the planar driving electrode in the middle is a sawtooth electrode, the number of sawteeth of the sawtooth electrode is three, and the sawteeth of the sawtooth electrode correspond to the segmented electrodes one by one; The first main surface and the second main surface are two opposite surfaces.

2. The tuning fork type piezoelectric vibration piece according to claim 1, wherein The driving groove is an integral groove, and the depth of the driving groove accounts for not more than 80% of the thickness of the vibration arm part.

3. The tuning fork type piezoelectric vibration piece according to claim 1, wherein Along the length direction of the vibration arm part, the bottom of the driving groove is provided with a separation beam, which separates the driving groove into two grooves with the same width, and the depth of the driving groove accounts for not more than 85% of the thickness of the vibration arm part.

4. The tuning fork type piezoelectric vibration piece according to claim 1, wherein The length of the driving groove accounts for 40%-70% of the length of the vibration arm part, and the width of the driving groove accounts for 35%-65% of the width of the vibration arm part.

5. The tuning fork type piezoelectric vibration piece according to claim 1, wherein The length of the planar driving electrode is the same as the length of the driving groove.

6. The tuning fork type piezoelectric vibration piece according to claim 1, wherein The polarities of the three planar driving electrodes alternate; The polarity of the side wall driving electrode of the vibration arm part is the same as that of the planar driving electrodes on the two sides of the three planar driving electrodes of the second main surface of the vibration arm part, and is opposite to that of the inner wall driving electrode of the driving groove of the first main surface of the vibration arm part.

7. The tuning fork type piezoelectric vibration piece according to any one of claims 1 to 6, wherein The first main surface of the vibration arm part is also provided with a small groove, the small groove is located at the root of the vibration arm part close to the base, and the depth of the small groove is the same as that of the driving groove; The inner wall of the small groove is provided with an inner wall driving electrode, and the polarity of the inner wall driving electrode of the small groove is the same as that of the inner wall driving electrode of the driving groove.

8. The tuning fork type piezoelectric vibration piece according to any one of claims 1 to 6, wherein The base is provided with a plurality of width reduction parts which are completely through in thickness near the vibration arm part, and the width reduction parts on both sides of the base are symmetrically arranged; The width reduction parts on each side of the base are arranged in a zigzag shape in parallel and have the same spacing.

9. An oscillator characterized by The vibration arm part comprises a base and two vibration arm parts extending from one end of the base, the two vibration arm parts are symmetrically arranged, and the polarities of the driving electrodes at corresponding positions are opposite; for each vibration arm part:

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