Electroacoustic transducer, resonator, and filter

Abstract

The invention relates to an electroacoustic transducer, a resonator and a filter. The electroacoustic transducer comprises a piezoelectric substrate and an interdigital transducer, wherein the interdigital transducer is positioned on the surface of the piezoelectric substrate; the interdigital transducer comprises a pair of bus bars and two groups of IDT finger bars which are alternately arranged at intervals; the two groups of IDT finger strips are positioned between the pair of bus bars and are alternately arranged at intervals along the extension direction of the bus bars; each IDT finger strip comprises a main IDT area, and each main IDT area is internally provided with a slit. According to the electroacoustic transducer, the transverse mode in the electroacoustic transducer can be effectively suppressed by adjusting the SAW speed in the main IDT region, and the influence of the transverse mode on the frequency response of the resonator is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of acoustic devices, and in particular to an electroacoustic transducer, a resonator, and a filter. Background Art

[0002] A surface acoustic wave (SAW) resonator includes a piezoelectric substrate and an interdigital transducer (IDT) formed by interdigital electrodes. Due to the piezoelectric effect, the SAW resonator generates a surface acoustic wave and propagates as a main mode within the electrode grating. This resonant characteristic makes SAW resonators widely used in various acoustic devices. RF filters based on SAW resonators are often used in wireless communication devices. The increased frequency band and the restrictions on utilizing the RF spectrum require the use of SAW devices with excellent performance.

[0003] In a SAW resonator, transverse modes are generated simultaneously with the main mode and propagate in a direction perpendicular to the main mode. Transverse modes tend to distort the frequency response of the resonator, thereby reducing the performance of the resonator or the filter based on the resonator. Summary of the invention

[0004] Based on this, it is necessary to provide an electroacoustic transducer, a resonator, and a filter. When the electroacoustic transducer is applied to a resonator, it can suppress the transverse mode and reduce the influence of the transverse mode on the frequency response of the resonator.

[0005] In a first aspect, the present application provides an electroacoustic transducer, comprising: a piezoelectric substrate and an interdigital transducer, wherein the interdigital transducer is located on a surface of the piezoelectric substrate;

[0006] The interdigital transducer comprises a pair of bus bars and two groups of IDT fingers arranged at alternating intervals; the two groups of IDT fingers are both located between the pair of bus bars and are arranged at alternating intervals along the direction in which the bus bars extend;

[0007] Each of the IDT fingers includes a main IDT region, and each of the main IDT regions is provided with a slit.

[0008] In some embodiments, the width of the slit is smaller than the width of the main IDT region; along the extension direction of the main IDT region, the center line of the gap coincides with the center line of the slit.

[0009] In some embodiments, the width of the slit is less than or equal to 1 / 3 of the width of the main IDT region where the slit is located.

[0010] In some embodiments, the slit penetrates or partially penetrates the IDT finger along the thickness direction of the IDT finger.

[0011] In some embodiments, each of the IDT fingers further includes: a gap region and a piston region; the gap region is located between the main IDT region and the bus bar; the piston region is located between the gap region and the main IDT region, and / or the main IDT region is away from one side of the gap region.

[0012] In some embodiments, the width of the piston region is greater than the width of the main IDT region.

[0013] In some embodiments, the widths of the slits on adjacent IDT fingers are different.

[0014] In some embodiments, a portion of each main IDT region is provided with a plurality of slits, and the plurality of slits in each main IDT region are arranged at intervals along the length direction of the main IDT region.

[0015] In some embodiments, the electroacoustic transducer further includes an additional bus bar, which is arranged parallel to and spaced apart from the bus bar and extends from between the IDT finger and the bus bar to cross the gap region.

[0016] In some embodiments, the electroacoustic transducer further includes a passive element, wherein the passive element is located between adjacent IDT fingers and is spaced apart from the IDT fingers.

[0017] In some embodiments, the lengths of the slits on adjacent IDT fingers are different.

[0018] In some embodiments, the slits on adjacent IDT fingers are staggered along the length direction of the bus bar.

[0019] In a second aspect, the present application provides a resonator comprising any of the above-mentioned electroacoustic transducers.

[0020] In a third aspect, the present application provides a filter comprising the above-mentioned resonator.

[0021] The above-mentioned electroacoustic transducer includes a piezoelectric substrate and an interdigital transducer, wherein each IDT finger of the interdigital transducer includes a main IDT region, and each main IDT region is provided with a slit. The slit can increase the speed of the SAW in the main IDT region and reduce the reflection from the electrode grating. By adjusting the SAW speed in the main IDT region, the transverse mode in the electroacoustic transducer can be effectively suppressed, reducing the influence of the transverse mode on the frequency response of the resonator. Furthermore, by designing the structure of the slit and other parts of the interdigital transducer, the transverse mode can be almost completely suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a frequency response diagram of a conventional SAW resonator provided by the present application with transverse mode spurious;

[0023] FIG2 is a schematic diagram of a finite element simulation of the lateral mode resonant frequency and the total response displacement of a conventional SAW resonator provided by the present application;

[0024] FIG3 is a schematic diagram of a partial structure of an IDT provided in an embodiment of the present application;

[0025] FIG4 is a schematic diagram of a partial structure of an IDT provided in another embodiment of the present application;

[0026] FIG5 is a schematic diagram of a partial structure of an IDT provided in another embodiment of the present application;

[0027] FIG6 is a schematic diagram of a partial structure of an IDT provided in another embodiment of the present application;

[0028] FIG7 is a schematic diagram of a partial structure of an IDT provided in another embodiment of the present application;

[0029] FIG8 is a schematic diagram of a partial structure of an IDT provided in another embodiment of the present application;

[0030] FIG9 is a schematic diagram of a partial structure of an IDT provided in another embodiment of the present application;

[0031] FIG10 is a schematic diagram of a partial structure of an IDT provided in another embodiment of the present application;

[0032] FIG11 is a schematic diagram of a partial structure of an IDT provided in another embodiment of the present application;

[0033] FIG. 12 is a schematic diagram of a partial structure of an IDT provided in another embodiment of the present application.

[0034] Description of Reference Numerals

[0035] 10. Bus bar; 20. IDT finger; 30. Slit; 40. Main IDT region; 50. Gap region; 60. Piston region; 70. Additional bus bar; 80. Passive components. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0038] Referring to Figures 1 and 2, Figure 1 is a frequency response diagram of a traditional SAW resonator with transverse mode spurious, and Figure 2 is a finite element simulation diagram of the transverse mode resonant frequency and the total response displacement of a traditional SAW resonator. It can be seen that in the traditional SAW resonator, the transverse mode is generated simultaneously with the main mode, and the transverse mode propagates in a direction perpendicular to the main mode.

[0039] An embodiment of the present application provides an electroacoustic transducer, comprising: a piezoelectric substrate and an interdigital transducer, wherein the interdigital transducer is located on the surface of the piezoelectric substrate. Referring to FIG3 , the interdigital transducer comprises a pair of bus bars 10 and two groups of IDT fingers 20 arranged alternately and spaced apart, wherein the two groups of IDT fingers 20 are both located between the pair of bus bars 10 and are arranged alternately and spaced apart along the direction in which the bus bars 10 extend. Each IDT finger 20 comprises a main IDT region 40, and each main IDT region 40 is provided with a slit 30.

[0040] It can be understood that the dotted lines in the drawings are only used to facilitate the distinction between the various parts of the IDT, and are not actual lines in the device.

[0041] In a possible embodiment, there is a certain distance between the slit 30 and the end of the IDT finger 20 away from the corresponding bus bar 10 , and the distance may be 5λ-20λ.

[0042] The electroacoustic transducer comprises a piezoelectric substrate and an interdigital transducer, wherein each IDT finger 20 of the interdigital transducer comprises a main IDT region 40, and each main IDT region 40 is provided with a slit 30. The slit 30 can increase the speed of the SAW in the main IDT region 40 and reduce the reflection from the electrode grating. By adjusting the SAW speed in the main IDT region 40, the transverse mode in the electroacoustic transducer can be effectively suppressed, reducing the influence of the transverse mode on the frequency response of the resonator.

[0043] In some embodiments, the slit 30 is rectangular. It is understood that the shape of the slit 30 can be any shape, including but not limited to a rectangle. The change in the shape of the slit 30 has little effect on the propagation direction of the surface acoustic wave.

[0044] In some embodiments, the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The coincidence of the center line of the main IDT region 40 with the center line of the slit 30 means that the slit 30 in the main IDT region 40 is a bilaterally symmetrical structure. If the slit 30 in the main IDT region 40 is an asymmetric structure, it will cause uneven propagation of the surface acoustic wave in the resonator, thereby reducing the performance of the resonator. However, it is worth mentioning that the slit line that is evenly split along the length direction of the IDT finger 20 may have a beneficial effect on the propagation and lateral suppression of the surface acoustic wave.

[0045] In some embodiments, the width of the slit 30 is less than or equal to 1 / 3 of the width of the main IDT region 40 in which it is located. Optionally, the width of the slit 30 is 1 / 10 to 1 / 3 of the width of the main IDT region 40 in which it is located. Further optionally, the width of the slit 30 is 1 / 10, 1 / 9, 1 / 8, 1 / 7, 1 / 6, 1 / 5, 1 / 4 or 1 / 3 of the width of the main IDT region 40 in which it is located. Preferably, the width of the slit 30 is 1 / 5 of the width of the main IDT region 40 in which it is located, and at this width of the slit 30, almost complete suppression of the lateral mode can be achieved.

[0046] In some embodiments, the slit 30 penetrates or partially penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. It can be understood that the slit 30 penetrates or partially penetrates the IDT finger 20 along the thickness direction of the IDT finger 20 by partially or completely removing the metal material in the preset preparation area of ​​the slit 30 on the IDT finger 20. In the interdigital transducer with slits 30 in the present application, the main factor affecting the effect of suppressing the lateral mode is the area of ​​the slit 30, that is, the total area of ​​the metal material removed (to form the slit 30) on the IDT finger 20.

[0047] Referring to FIG. 3 again, in some embodiments, each IDT finger 20 further includes: a gap region 50 and a piston region 60. The gap region 50 is located between the main IDT region 40 and the bus bar 10. The piston region 60 is located between the gap region 50 and the main IDT region 40, and on the side of the main IDT region 40 away from the gap region 50. It can be understood that the piston region 60 is a gap between the slit 30 and the end of the IDT finger 20 away from the bus bar 10, and the gap is the piston region 60. The piston region 60 is not provided with a slit 30. Since the main IDT region 40 is provided with a slit 20, the area of ​​the piston region 60 is larger than the area of ​​the main IDT region 40, which can reduce the speed of the SAW in the piston region 60 and improve the lateral suppression effect of the interdigital transducer.

[0048] 4, in some embodiments, the width of the piston region 60 is greater than the width of the main IDT region 40. It is understandable that the width of the piston region 60 being greater than the width of the main IDT region 40 means that the IDT has a hammerhead structure. An IDT having only a hammerhead structure but not a slit 30 can suppress the transverse mode, however, the slit 30 can further enhance the suppression effect of the IDT having a hammerhead structure on the transverse mode, that is, the slit 30 structure can not only be used to improve the traditional IDT, but also can be used to improve the IDT having a hammerhead structure.

[0049] In some embodiments, the length of the piston region 60 is 3 to 4 times the width of the slit 30. Within the length range of the piston region 60, the lateral suppression effect is better and the performance of the resonator is better.

[0050] In some embodiments, the distance between adjacent main IDT regions 40 is equal to the width of the main IDT region 40 .

[0051] In some embodiments, the widths of the slits 30 on adjacent IDT fingers 20 are different.

[0052] In some embodiments, a plurality of slits 30 are disposed in each main IDT region 40 , and the plurality of slits 30 in each main IDT region 40 are arranged at intervals along the length direction of the main IDT region 40 .

[0053] In some embodiments, a plurality of slits 30 are disposed in each main IDT region 40 , and different slits 30 in a single main IDT region 40 have different lengths.

[0054] In some embodiments, a plurality of slits 30 are disposed in each main IDT region 40 , and different slits 30 in a single main IDT region 40 have different widths.

[0055] In some embodiments, a plurality of slits 30 are disposed in each main IDT region 40 , and the numbers of slits 30 in adjacent main IDT regions 40 are different.

[0056] In some embodiments, the electroacoustic transducer further includes an additional bus bar 70 , which is arranged parallel to and spaced from the bus bar 10 , extends from between the IDT fingers 20 and the bus bar 10 , crosses the gap region 50 , and is connected to the gap region 50 .

[0057] In some embodiments, the electroacoustic transducer further includes a passive element 80, which is located between adjacent IDT fingers 20 and is spaced apart from the IDT fingers 20. Optionally, the passive element 80 includes one of a single capacitor element, a parallel capacitor element, a single inductor element, and a series inductor element. For example, the use of parallel capacitors between adjacent IDT fingers 20 can achieve a symmetrical AC potential distribution within the length range of the IDT fingers 20, which can have a positive effect on the SAW energy limitation in the propagation direction. It is understood that the passive element 80 can be formed by embedding a dielectric layer or a layer with a high dielectric constant in the region between the IDT fingers 20 during the manufacturing process of the interdigital transducer, or by using an insulator-metal laminated element in the region between the IDT fingers 20.

[0058] In some embodiments, the lengths of the slits 30 on adjacent IDT fingers 20 are different.

[0059] In some embodiments, the slits 30 on adjacent IDT fingers 20 are staggered along the length direction of the bus bar 10 .

[0060] In some embodiments, the slits 30 on different IDT fingers 20 are symmetrically apodized along the length direction of the bus bar 10. In other embodiments, the slits 30 on different IDT fingers 20 are asymmetrically apodized along the length direction of the bus bar 10. When the slits 30 on different IDT fingers 20 are symmetrically or asymmetrically apodized along the length direction of the bus bar 10, the performance of the resonator may be reduced, but a better lateral suppression effect can be obtained.

[0061] It should be noted that the above embodiment only takes the IDT including real fingers as an example. In actual implementation, the IDT may also include fake fingers. Of course, in actual implementation, slits may also be provided in the fake fingers. This embodiment does not limit its specific implementation.

[0062] In some embodiments, the IDT is an aluminum IDT or a copper IDT.

[0063] In some embodiments, the piezoelectric substrate is a lithium tantalate piezoelectric substrate or a lithium niobate piezoelectric substrate.

[0064] Yet another embodiment of the present application provides a resonator, comprising any one of the above-mentioned electroacoustic transducers.

[0065] Yet another embodiment of the present application provides a filter, comprising the above-mentioned resonator.

[0066] The following is a specific implementation method

[0067] Example 1

[0068] Please refer to FIG. 3 again. This embodiment provides an implementation scheme of an IDT. The IDT in this embodiment includes a pair of bus bars 10 and two groups of IDT fingers 20. The two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40. Each main IDT region 40 is provided with a slit 30. The slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10. The slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes a gap region 50 and a piston region 60. The gap region 50 is located between the main IDT region 40 and the bus bar 10. The piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular and its width is smaller than that of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The distance between adjacent IDT fingers 20 is equal to the width of the IDT fingers 20.

[0069] Example 2

[0070] Referring again to FIG. 4 , this embodiment provides another possible implementation scheme of an IDT, wherein the IDT in this embodiment includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, each main IDT region 40 is provided with a slit 30, the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The distance between adjacent main IDT regions 40 is equal to the width of the main IDT region 40. The width of the piston region 60 is greater than the width of the main IDT region 40. That is, the interdigital transducer has a hammer head structure.

[0071] Example 3

[0072] Referring to FIG. 3 again, the interdigital transducer in this embodiment includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, and each main IDT region 40 is provided with a slit 30, and the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extending direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The ratio of the distance between adjacent main IDT regions 40 to the width of the main IDT region 40 is 3:7.

[0073] Example 4

[0074] 5 , this embodiment provides an implementation scheme of an IDT, wherein the IDT in this embodiment includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, each main IDT region 40 is provided with a slit 30, the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The widths of the slits 30 on adjacent IDT fingers 20 are different. In this embodiment, adjacent IDT fingers 20 in the interdigital transducer have asymmetric slits 30, which can be used to form directional surface acoustic waves.

[0075] Example 5

[0076] Referring to FIG. 6 , this embodiment provides an implementation scheme of an IDT, wherein the IDT in this embodiment includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, each main IDT region 40 is provided with a slit 30, the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The distance between adjacent main IDT regions 40 is equal to the width of the main IDT region 40. A plurality of slits 30 are provided in each main IDT region 40, and the plurality of slits 30 in each main IDT region 40 are arranged at intervals along the length direction of the main IDT region 40, and the number of slits 30 in adjacent main IDT regions 40 is different.

[0077] Example 6

[0078] Referring to FIG. 7 , this embodiment provides an implementation scheme of an IDT, which includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, each main IDT region 40 is provided with a slit 30, the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The distance between adjacent main IDT regions 40 is equal to the width of the main IDT region 40. Multiple slits 30 are provided in each main IDT region 40, and the multiple slits 30 in each main IDT region 40 are arranged at intervals along the length direction of the main IDT region 40, and the lengths and widths of the multiple slits 30 in each main IDT region 40 are different. The interdigital transducer of this structure can be used for phase and speed control.

[0079] Example 7

[0080] 8 , this embodiment provides an implementation scheme of an IDT, wherein the IDT in this embodiment includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, each main IDT region 40 is provided with a slit 30, the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The distance between adjacent main IDT regions 40 is equal to the width of the main IDT region 40. The electroacoustic transducer also includes an additional bus bar 70, which is arranged parallel to the bus bar 10 and extends from between the IDT finger 20 and the bus bar 10 to cross the gap region 50 and is connected to the gap region 50. The slit 30 structure can be used in conjunction with the hammer head structure and the additional bus bar 70 structure.

[0081] Example 8

[0082] 9 , this embodiment provides an implementation scheme of an IDT, wherein the IDT in this embodiment includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, each main IDT region 40 is provided with a slit 30, the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The distance between adjacent main IDT regions 40 is equal to the width of the main IDT region 40. The electroacoustic transducer further includes a passive element 80, which is located between adjacent IDT fingers 20 and spaced apart from the IDT fingers 20. In this embodiment, the passive element 80 is an additional metal element located on the piezoelectric layer substrate.

[0083] Example 9

[0084] Referring to FIG. 10 , this embodiment provides an implementation scheme of an IDT, which includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are alternately arranged along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, each main IDT region 40 is provided with a slit 30, the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The lengths of the slits 30 on adjacent IDT fingers 20 are different. Along the length direction of the bus bar 10, the slit 30 is linearly or nonlinearly apodized. In this embodiment, along the length direction of the bus bar 10, the length of the slit 30 first increases and then decreases and is linearly apodized.

[0085] Example 10

[0086] Referring to FIG. 11 , this embodiment provides an implementation scheme of an IDT, wherein the IDT in this embodiment includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, each main IDT region 40 is provided with a slit 30, the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The slits 30 on adjacent IDT fingers 20 are staggered along the length direction of the bus bar 10. In this embodiment, the lengths of the slits 30 on different IDT fingers 20 are the same, and along the length direction of the bus bar 10, the distance between the slits 30 on different IDT fingers 20 and one of the bus bars 10 gradually increases.

[0087] Embodiment 11

[0088] Referring to FIG. 12 , this embodiment provides an implementation scheme of an IDT, wherein the IDT in this embodiment includes a pair of bus bars 10 and two groups of IDT fingers 20; the two groups of IDT fingers 20 are located between the pair of bus bars 10 and are arranged alternately and spaced along the direction in which the bus bars 10 extend. Each IDT finger 20 includes a main IDT region 40, each main IDT region 40 is provided with a slit 30, the slit 30 is spaced from the end of the IDT finger 20 away from the bus bar 10, and the slit 30 penetrates the IDT finger 20 along the thickness direction of the IDT finger 20. Each IDT finger 20 also includes: a gap region 50 and a piston region 60; the gap region 50 is located between the main IDT region 40 and the bus bar 10; the piston region 60 is located between the gap region 50 and the main IDT region 40 and on the side of the main IDT region 40 away from the gap region 50. The slit 30 is rectangular, and the width of the slit 30 is smaller than the width of the main IDT region 40. Along the extension direction of the main IDT region 40, the center line of the main IDT region 40 coincides with the center line of the slit 30. The lengths of the slits 30 on different IDT fingers 20 are different, and along the length direction of the bus bar 10, the lengths of the slits 30 on different IDT fingers 20 gradually increase.

[0089] The implementation methods of the IDTs in the above Embodiments 1 to 11 can all achieve the suppression of the transverse mode in the electroacoustic transducer and the SAW resonator.

[0090] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims, and the description and drawings may be used to interpret the contents of the claims.

Claims

1. An electroacoustic transducer, characterized in that: include: A piezoelectric substrate and an interdigital transducer, wherein the interdigital transducer is located on a surface of the piezoelectric substrate; The interdigital transducer comprises a pair of bus bars and two groups of IDT fingers; the two groups of IDT fingers are both located between the pair of bus bars and are alternately arranged along the direction in which the bus bars extend; Each of the IDT fingers includes a main IDT region, and each of the main IDT regions is provided with a slit.

2. The electroacoustic transducer according to claim 1, characterized in that: The width of the slit is smaller than the width of the main IDT region; along the extension direction of the main IDT region, the center line of the main IDT region coincides with the center line of the slit.

3. The electroacoustic transducer according to claim 2, characterized in that: The width of the slit is less than or equal to 1 / 3 of the width of the main IDT region where the slit is located.

4. The electroacoustic transducer according to claim 1, characterized in that: The slit penetrates or partially penetrates the IDT finger along the thickness direction of the IDT finger.

5. The electroacoustic transducer according to claim 1, characterized in that: Each of the IDT fingers further comprises: a gap region and a piston region; the gap region is located between the main IDT region and the bus bar; the piston region is located between the gap region and the main IDT region, and / or the main IDT region is away from the gap region.

6. The electroacoustic transducer according to claim 5, characterized in that: The width of the piston region is greater than the width of the main IDT region.

7. The electroacoustic transducer according to claim 5, characterized in that: The electroacoustic transducer further comprises an additional bus bar, which is arranged in parallel and spaced apart from the bus bar, and extends from between the IDT finger and the bus bar to cross the gap area; And / or, the electroacoustic transducer further includes a passive element, wherein the passive element is located between adjacent IDT fingers and is spaced apart from the IDT fingers.

8. The electroacoustic transducer according to any one of claims 1 to 7, characterized in that: The widths of the slits on adjacent IDT fingers are different; And / or, each of the main IDT regions is provided with a plurality of slits, and the plurality of slits in each of the main IDT regions are arranged at intervals along the length direction of the main IDT region; and / or, the lengths of the slits on adjacent IDT fingers are different; And / or, the slits on adjacent IDT fingers are staggered along the length direction of the bus bar.

9. A resonator, characterized in that: The invention comprises the electroacoustic transducer as described in any one of claims 1 to 8.

10. A filter, characterized in that: Comprising the resonator of claim 9.

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