阅读说明：本技术 一种基于压电薄膜的芯片化发声器件 (Chip sounding device based on piezoelectric film ) 是由 李岚硕 于 2021-09-14 设计创作，主要内容包括：本发明公开了一种基于压电薄膜的芯片化发声器件,属于压电微机械发声器技术领域,解决了现有技术中的发声器件结构复杂导致功耗高、性能差的问题,本发明包括底部基板,底部基板上连接有核心芯片,底部基板上方连接有非金属管壳,非金属管壳上开设有出音孔,核心芯片包括由下至上依次连接的硅基底层、硅结构层和压电材料层,压电材料层上设置有压电振膜,压电振膜上连接有金属激励电极,金属激励电极的尺寸小于压电振膜的尺寸,压电振膜周围的压电材料层上开设有隔离槽,压电材料层上还安装有与金属激励电极连接的激励电极焊盘,激励电极焊盘旁还安装有接地电极焊盘。本发明应用于受话器、扬声器、蜂鸣器等发声装置的发声器件。(The invention discloses a chip sounder based on a piezoelectric film, which belongs to the technical field of piezoelectric micro-mechanical sounders and solves the problems of high power consumption and poor performance caused by complex structure of the sounder in the prior art. The piezoelectric vibrating diaphragm is arranged on the piezoelectric material layer, a metal excitation electrode is connected onto the piezoelectric vibrating diaphragm, the size of the metal excitation electrode is smaller than that of the piezoelectric vibrating diaphragm, an isolation groove is formed in the piezoelectric material layer around the piezoelectric vibrating diaphragm, an excitation electrode bonding pad connected with the metal excitation electrode is further installed on the piezoelectric material layer, and a grounding electrode bonding pad is further installed beside the excitation electrode bonding pad. The invention is applied to the sounding devices of the sounding devices such as a telephone receiver, a loudspeaker, a buzzer and the like.)

1. A chip sound production device based on a piezoelectric film is characterized by comprising a bottom substrate (2), wherein a core chip (1) is connected onto the bottom substrate (2), a non-metal tube shell (4) is connected above the bottom substrate (2), an air vibration cavity (6) is formed between the interior of the non-metal tube shell (4) and the bottom substrate (2), a sound outlet (5) is formed on the non-metal tube shell (4), a sound collection cavity (7) is formed in the interior of the sound outlet (5), the core chip (1) comprises a silicon substrate layer (12), a silicon structure layer (13) and a piezoelectric material layer (14) which are sequentially connected from bottom to top, a piezoelectric vibrating diaphragm (15) is arranged on the piezoelectric material layer (14), a metal excitation electrode (16) is connected onto the piezoelectric vibrating diaphragm (15), and the size of the metal excitation electrode (16) is smaller than that of the piezoelectric vibrating diaphragm (15), an isolation groove (19) is formed in a piezoelectric material layer (14) on the periphery of the piezoelectric diaphragm (15), an excitation electrode bonding pad (17) connected with a metal excitation electrode (16) is further installed on the piezoelectric material layer (14), and a grounding electrode bonding pad (18) is further installed beside the excitation electrode bonding pad (17).

2. The chip-type sound production device based on the piezoelectric film according to claim 1, wherein a waterproof and dustproof mesh (8) is connected to the inner wall of the non-metal tube shell (4) between the sound collection cavity (7) and the air vibration cavity (6), a signal pad (9), a ground pad (10) and an auxiliary pad (11) are further respectively mounted on the bottom surface of the bottom substrate (2), and a gold lead (3) is connected between the signal pad (9), the ground pad (10) and the auxiliary pad (11) and a metal excitation electrode (16) pad.

3. The chip-type sound production device based on the piezoelectric film according to claim 1, wherein the piezoelectric diaphragm (15) on the piezoelectric material layer (14) is circular, the metal excitation electrode (16) on the piezoelectric diaphragm (15) is also circular, the piezoelectric diaphragm (15) and the metal excitation electrode (16) are arranged in 4 groups, the 4 groups of metal excitation electrodes (16) are sequentially communicated end to end and communicated with the excitation electrode pad (17), and 4 arc-shaped isolation grooves (19) are arranged around each group of piezoelectric diaphragm (15).

4. The piezoelectric film-based chip sound production device according to claim 1, wherein the piezoelectric diaphragm (15) on the piezoelectric material layer (14) is circular, the metal excitation electrode (16) on the piezoelectric diaphragm (15) is also circular, 1 group of the piezoelectric diaphragm (15) and the metal excitation electrode (16) are arranged on the piezoelectric material layer (14), and 4 arc-shaped isolation grooves (19) are circumferentially arranged around the piezoelectric diaphragm (15).

5. The chip-type sound production device based on the piezoelectric film according to claim 1, wherein the piezoelectric diaphragm (15) on the piezoelectric material layer (14) is square, the metal excitation electrodes (16) on the piezoelectric diaphragm (15) are also square, the piezoelectric diaphragm (15) and the metal excitation electrodes (16) are arranged in 4 groups, the 4 groups of metal excitation electrodes (16) are sequentially communicated end to end and communicated with the excitation electrode pad (17), and 4L-shaped isolation grooves (19) are circumferentially arranged around each group of piezoelectric diaphragm (15).

6. The piezoelectric film-based chip sound production device according to claim 1, wherein the piezoelectric diaphragm (15) on the piezoelectric material layer (14) is square, the metal excitation electrode (16) on the piezoelectric diaphragm (15) is also square, 1 group of the piezoelectric diaphragm (15) and the metal excitation electrode (16) are arranged on the piezoelectric material layer (14), and 4L-shaped isolation grooves (19) are circumferentially arranged around the piezoelectric diaphragm (15).

7. The chip-based sound production device based on the piezoelectric film as claimed in claim 1, wherein the sound outlet hole (5) is in a truncated cone shape, 1 sound outlet hole (5) is formed in the non-metal tube shell (4), and the cross-sectional area of the hole of the truncated cone-shaped sound outlet hole (5) on the outer wall of the non-metal tube shell (4) is larger than that of the hole on the inner wall of the non-metal tube shell (4).

8. The chip-type sound production device based on piezoelectric film as claimed in claim 1, wherein the sound outlet (5) is oval, and 2 sound outlets (5) are disposed on the non-metal tube shell (4).

Technical Field

The invention belongs to the technical field of piezoelectric micromechanical sounders, and particularly relates to a chip sounder based on a piezoelectric film.

Background

The existing sounding device has two main technologies, namely an electromagnetic type and a piezoelectric ceramic type. Both techniques have their advantages, but have the disadvantages of large volume, high cost, and poor consistency.

The electromagnetic sounding device is an electronic device which uses the action of an electromagnetic coil on a buzzer to sound, and attracts a vibrating membrane when the device is powered on, and the metal vibrating membrane rebounds when the device is powered off. The electromagnetic sounding device is divided into two categories, namely a passive type and an active type, and comprises a coil and a magnet, and the active buzzer further comprises a driving circuit. The electromagnetic buzzer has low driving voltage but consumes large current. The structure is comparatively complicated, and the installation is inconvenient, because there is magnet, and weight is great relatively, easily causes electromagnetic interference to the circuit, also receives the interference easily.

The piezoelectric ceramic sounding device is made of piezoelectric buzzers, the piezoelectric buzzers are made of piezoelectric ceramics, and electrodes need to be plated on two surfaces of each piezoelectric buzzer for electrifying. After an alternating current driving signal is applied to the piezoelectric buzzer, the piezoelectric buzzer can generate mechanical deformation extension and contraction due to the piezoelectric effect, and the metal sheet attached to the piezoelectric ceramic sheet can be pushed to vibrate to make a sound. The piezoelectric ceramic sounding device is also classified into a passive type and an active type, and the active buzzer further comprises a driving circuit. The advantages are long service life, high reliability, no generation of flashover or radio frequency noise, and no interference to other lines. Because the voltage is used for excitation, the consumed current is small, generally below 20mA and not more than 100 mA. However, the piezoelectric ceramic type sound generating device has the defects of high driving voltage, high cost, large volume and poor consistency due to the sintering process of the piezoelectric ceramic.

Disclosure of Invention

The invention aims to:

in order to solve the problems of high power consumption and poor performance caused by the complicated structure of the sounding device in the prior art, a chip sounding device based on a piezoelectric film is provided.

The technical scheme adopted by the invention is as follows:

a chip sounding device based on piezoelectric film comprises a bottom substrate, a core chip connected to the bottom substrate, a non-metal tube shell connected to the bottom substrate, an air vibration cavity is formed between the interior of the non-metal tube shell and the bottom substrate, a sound outlet hole is formed on the non-metal tube shell, the sound outlet hole is internally provided with a sound collecting cavity, the core chip comprises a silicon substrate layer, a silicon structure layer and a piezoelectric material layer which are sequentially connected from bottom to top, a piezoelectric vibrating diaphragm is arranged on the piezoelectric material layer, a metal excitation electrode is connected on the piezoelectric vibrating diaphragm, the size of the metal excitation electrode is smaller than that of the piezoelectric vibrating diaphragm, the piezoelectric vibration film is characterized in that an isolation groove is formed in a piezoelectric material layer around the piezoelectric vibration film, an excitation electrode bonding pad connected with a metal excitation electrode is further installed on the piezoelectric material layer, and a grounding electrode bonding pad is further installed beside the excitation electrode bonding pad.

Furthermore, a waterproof and dustproof net is connected to the inner wall of the non-metal tube shell between the sound collection cavity and the air vibration cavity, a signal bonding pad, a grounding bonding pad and an auxiliary bonding pad are further mounted on the bottom surface of the bottom substrate respectively, and gold leads are connected between the signal bonding pad, the grounding bonding pad, the auxiliary bonding pad and the metal excitation electrode bonding pad.

Furthermore, the piezoelectric diaphragm on the piezoelectric material layer is circular, the metal excitation electrode on the piezoelectric diaphragm is also circular, the piezoelectric diaphragm and the metal excitation electrode array are provided with 4 groups, the head and the tail of the 4 groups of metal excitation electrodes are sequentially communicated and are communicated with the excitation electrode bonding pad, and 4 arc isolation grooves are arranged around each group of piezoelectric diaphragm.

Further, the piezoelectric diaphragm on the piezoelectric material layer is circular, the metal excitation electrode on the piezoelectric diaphragm is also circular, 1 group of piezoelectric diaphragm and metal excitation electrode is arranged on the piezoelectric material layer, and 4 arc-shaped isolation grooves are arranged around the piezoelectric diaphragm.

Furthermore, the piezoelectric diaphragm on the piezoelectric material layer is square, the metal excitation electrodes on the piezoelectric diaphragm are also square, the piezoelectric diaphragm and the metal excitation electrode array are provided with 4 groups, the 4 groups of metal excitation electrodes are sequentially communicated from head to tail and communicated with the excitation electrode bonding pad, and 4L-shaped isolation grooves are arranged around each group of piezoelectric diaphragm in a surrounding manner.

Further, the piezoelectric diaphragm on the piezoelectric material layer is square, the metal excitation electrode on the piezoelectric diaphragm is also square, 1 group of piezoelectric diaphragm and metal excitation electrode is arranged on the piezoelectric material layer, and 4L-shaped isolation grooves are arranged around the piezoelectric diaphragm.

Furthermore, the inside of the sound outlet hole is in a round table shape, 1 sound outlet hole is formed in the non-metal pipe shell, and the cross-sectional area of an orifice of the round table shape sound outlet hole, which is located on the outer wall of the non-metal pipe shell, is larger than that of an orifice of the inner wall of the non-metal pipe shell.

Furthermore, the inside of going out the sound hole is the ellipse, goes out the sound hole and is provided with 2 on non-metal pipe shell.

The invention provides a piezoelectric film-based chip sounding device, which is manufactured by manufacturing a Micro-Electro-Mechanical System (MEMS) core chip based on a piezoelectric film by using a semiconductor technology and packaging the chip. The device has the main function of converting the electric signals into audible sound signals of human ears, and the frequency range of the sound signals is 20-20000 Hz.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. the MEMS core chip is manufactured by a standardized wafer-level MEMS process, and the consistency of the materials and the performance of the chip is extremely high. The device level packaging is completed by adopting automatic packaging equipment, and has the characteristics of low cost and high performance. The chip sounding device has the advantages of simple structure, small volume, light weight, low power consumption and interference resistance, and does not bring electromagnetic interference to a circuit.

2. The invention relates to a chip sounding device, which is a breakthrough application of a piezoelectric film technology in the field of sounding devices, and can perform special design on the structure of an MEMS (micro-electromechanical systems) core chip and the structure of an air cavity in a non-metal outer tube shell according to specific application scenes of a receiver, a loudspeaker, a buzzer and the like so as to improve and improve the output performance of the sounding device under specific requirements.

3. The chip sounding device has the advantages of miniaturization and integration, the size of the whole device is about 6.0mm 2.0mm, the chip sounding device is an extremely small-sized sounding device, and the chip sounding device can be further miniaturized according to application.

4. Because the MEMS core chip in the chip sounding device adopts standardized manufacture and automatic packaging, the MEMS core chip can be sealed with other special or conventional integrated circuit chips to form a sounding device module of a buzzer, a loudspeaker and the like of an integrated drive circuit, and compared with the traditional sounding device module in the industry at present, the MEMS core chip has smaller size, lower cost and smaller power consumption.

Drawings

FIG. 1 is an exploded view of the whole structure of the sound-generating device of the present invention;

FIG. 2 is a bottom structure view of the chip-type sound generating device of the present invention;

fig. 3 is a schematic diagram of an embodiment of a circular 2x2 array chip structure according to the present invention;

FIG. 4 is a schematic view of a circular single tube structure chip embodiment of the present invention;

fig. 5 is a schematic diagram of an embodiment of a square 2x2 array chip structure according to the present invention;

FIG. 6 is a schematic diagram of a square single tube structure chip embodiment of the present invention;

FIG. 7 is a diagram of the non-metallic pipe case with oval sound holes according to the present invention;

FIG. 8 is a frequency response curve obtained from a free field test when the sound device of the present invention is used as a receiver;

FIG. 9 is a frequency response curve obtained from a test in a non-free field when the sound generating device of the present invention is applied as a speaker;

fig. 10 is a frequency response curve obtained by testing in a free field when the sound-producing device of the present invention is applied as a buzzer.

The labels in the figure are: 1-core chip, 2-bottom substrate, 3-gold lead, 4-nonmetal tube shell, 5-sound outlet, 6-air vibration cavity, 7-sound collection cavity, 8-waterproof dustproof net, 9-signal pad, 10-grounding pad, 11-auxiliary pad, 12-silicon substrate layer, 13-silicon structure layer, 14-piezoelectric material layer, 15-piezoelectric vibrating diaphragm, 16-metal excitation electrode, 17-excitation electrode pad, 18-grounding electrode pad and 19-isolation groove.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The basic embodiment of the invention is implemented as follows:

the basic structure of the chip sounder device based on the piezoelectric film is shown in figure 1. A MEMS core chip 1 manufactured by a MEMS process is packaged on a base substrate 2 containing external circuitry. The core chip 1 takes on the function of converting an electrical signal into an acoustic signal. The electrodes on the core chip 1 and the bonding pads on the base substrate 2 are connected by gold wires 3. The upper part of the device is a non-metallic pipe shell 4, and the top of the pipe shell is provided with a sound outlet 5. Wherein, the inside of the non-metal pipe shell 4 is an air vibration cavity 6 with certain shape and volume, and a sound collection cavity 7 is arranged between the sound outlet 5 and the air vibration cavity 6. In addition, in non-metal tube shell 4, between the top in air vibration chamber 6 and the bottom in sound collecting cavity 7, there is the structure of a waterproof dust screen 8, and this structure can block outside steam and small dust and get into air vibration chamber 6, and waterproof dust screen 8 has fairly high toughness simultaneously, makes sound in the transmission process, can not receive interference and the loss from waterproof dust screen 8.

The dimensions and shapes of the air vibration chamber 6 and the sound collecting chamber 7 have a crucial influence on the mechanical vibration performance and acoustic performance of the sound signal generated by the core chip 1 in air.

After the above components are combined and packaged, the actual configuration of the piezoelectric film-based chip sound production device is formed, as shown in fig. 2, three pads connected with an external circuit are left at the bottom of the device, including a signal pad 9, a ground pad 10 and an auxiliary pad 11. The auxiliary pad 11 has an independent shielding effect, and can improve the welding strength and improve the heat conduction. The size of the packaged piezoelectric film-based chip sound production device is about 6.0mm 2.0 mm.

Example 1

On the basis of the above basic scheme, preferably, as shown in fig. 3, the piezoelectric diaphragm 15 on the piezoelectric material layer 14 is circular, the metal excitation electrodes 16 on the piezoelectric diaphragm 15 are also circular, the piezoelectric diaphragm 15 and the metal excitation electrodes 16 are arranged in an array of 4 groups, the 4 groups of metal excitation electrodes 16 are sequentially communicated end to end and are communicated with the excitation electrode pad 17, and 4 arc-shaped isolation grooves 19 are circumferentially arranged around each group of piezoelectric diaphragm 15. The inside of sound outlet hole 5 is round platform shape, and sound outlet hole 5 is provided with 1 on non-metal tube shell 4, and the round platform shape sound outlet hole 5 is located the drill way sectional area on non-metal tube shell 4 outer wall and is greater than the drill way sectional area on non-metal tube shell 4 inner wall.

The sound generating device in the embodiment is a 2x2 array structure chip, the size is relatively large, the volume of sound generated by the device is large, and the device is more suitable for wide-band application due to the structural characteristics, such as a receiver, a loudspeaker and other scenes with high requirements on sound tone and sound quality. The circular piezoelectric diaphragm 15 has more excellent frequency response characteristics, high device quality factor, small mechanical loss, higher frequency consistency and larger frequency adjustable range.

Example 2

On the basis of the above basic scheme, preferably, as shown in fig. 4, the piezoelectric diaphragm 15 on the piezoelectric material layer 14 is circular, the metal excitation electrode 16 on the piezoelectric diaphragm 15 is also circular, 1 group of the piezoelectric diaphragm 15 and the metal excitation electrode 16 is arranged on the piezoelectric material layer 14, and 4 arc-shaped isolation grooves 19 are circumferentially arranged around the piezoelectric diaphragm 15. The inside of sound outlet hole 5 is round platform shape, and sound outlet hole 5 is provided with 1 on non-metal tube shell 4, and the round platform shape sound outlet hole 5 is located the drill way sectional area on non-metal tube shell 4 outer wall and is greater than the drill way sectional area on non-metal tube shell 4 inner wall.

The sound production device in the embodiment is a single-tube structure chip, the size of the sound production device is smaller than that of the sound production device in the embodiment 1, the sound production device is more beneficial to miniaturization application, and the sound production device has more advantages in the aspects of producing high-volume and high-frequency analog sound and intermittent sound, so that the sound production device is more suitable for being applied to the aspects of buzzers, alarms and the like.

Example 3

On the basis of the above basic scheme, preferably, as shown in fig. 5, the piezoelectric diaphragm 15 on the piezoelectric material layer 14 is square, the metal excitation electrodes 16 on the piezoelectric diaphragm 15 are also square, the piezoelectric diaphragm 15 and the metal excitation electrodes 16 are arranged in an array of 4 groups, the 4 groups of metal excitation electrodes 16 are sequentially communicated end to end and are communicated with the excitation electrode pad 17, and 4L-shaped isolation grooves 19 are circumferentially arranged around each group of piezoelectric diaphragm 15. The inside of sound outlet hole 5 is round platform shape, and sound outlet hole 5 is provided with 1 on non-metal tube shell 4, and the round platform shape sound outlet hole 5 is located the drill way sectional area on non-metal tube shell 4 outer wall and is greater than the drill way sectional area on non-metal tube shell 4 inner wall.

The chip structure of this embodiment is similar to that of embodiment 1, except that the square piezoelectric diaphragm 15 has higher vibration performance, larger vibration amplitude, wider frequency band, stronger carrying capacity, and larger output sound pressure.

Example 4

On the basis of the above basic scheme, preferably, as shown in fig. 6, the piezoelectric diaphragm 15 on the piezoelectric material layer 14 is square, the metal excitation electrode 16 on the piezoelectric diaphragm 15 is also square, 1 group of piezoelectric diaphragms 15 and metal excitation electrodes 16 are arranged on the piezoelectric material layer 14, and 4L-shaped isolation grooves 19 are circumferentially arranged around the piezoelectric diaphragm 15. The inside of sound outlet hole 5 is round platform shape, and sound outlet hole 5 is provided with 1 on non-metal tube shell 4, and the round platform shape sound outlet hole 5 is located the drill way sectional area on non-metal tube shell 4 outer wall and is greater than the drill way sectional area on non-metal tube shell 4 inner wall.

The present embodiment combines the advantages of the square piezoelectric diaphragm 15 and the miniaturized chip.

In the above embodiments 1-4, the circular truncated cone shaped sound emitting hole 5 is taken as an example, the design of the shape, size and position of the sound emitting hole 5 is closely related to the structure of the MEMS core chip 1 inside the device and the optimization of the acoustic performance of the device, different MEMS core chips 1 and different external tube shells of the sound emitting hole 5 are adopted, and the structure of the device is optimized according to the test performance, so that the frequency response curves of the piezoelectric film based chip sound emitting device of the present invention in different application scenarios can be obtained, as shown in fig. 10-12.

The following embodiments take the oval sound emitting hole 5 as an example, and as shown in fig. 7, the oval sound emitting hole can be arbitrarily combined with the chip structure.

Example 5

On the basis of the basic scheme, preferably, the piezoelectric diaphragm 15 on the piezoelectric material layer 14 is circular, the metal excitation electrodes 16 on the piezoelectric diaphragm 15 are also circular, 4 groups of piezoelectric diaphragms 15 and metal excitation electrodes 16 are arranged in an array, the 4 groups of metal excitation electrodes 16 are sequentially communicated end to end and communicated with the excitation electrode bonding pad 17, and 4 arc-shaped isolation grooves 19 are arranged around each group of piezoelectric diaphragms 15. The inside of sound outlet 5 is oval, and sound outlet 5 is provided with 2 on non-metal pipe shell 4.

Example 6

On the basis of the above basic scheme, preferably, the piezoelectric diaphragm 15 on the piezoelectric material layer 14 is circular, the metal excitation electrode 16 on the piezoelectric diaphragm 15 is also circular, 1 group of the piezoelectric diaphragm 15 and the metal excitation electrode 16 is arranged on the piezoelectric material layer 14, and 4 arc-shaped isolation grooves 19 are circumferentially arranged around the piezoelectric diaphragm 15. The inside of sound outlet 5 is oval, and sound outlet 5 is provided with 2 on non-metal pipe shell 4.

Example 7

On the basis of the basic scheme, preferably, the piezoelectric diaphragm 15 on the piezoelectric material layer 14 is square, the metal excitation electrodes 16 on the piezoelectric diaphragm 15 are also square, 4 groups of piezoelectric diaphragms 15 and metal excitation electrodes 16 are arranged in an array, the 4 groups of metal excitation electrodes 16 are sequentially communicated end to end and communicated with the excitation electrode bonding pad 17, and 4L-shaped isolation grooves 19 are arranged around each group of piezoelectric diaphragms 15. The inside of sound outlet 5 is oval, and sound outlet 5 is provided with 2 on non-metal pipe shell 4.

Example 8

On the basis of the above basic scheme, preferably, the piezoelectric diaphragm 15 on the piezoelectric material layer 14 is square, the metal excitation electrode 16 on the piezoelectric diaphragm 15 is also square, 1 group of piezoelectric diaphragms 15 and metal excitation electrodes 16 are arranged on the piezoelectric material layer 14, and 4L-shaped isolation grooves 19 are circumferentially arranged around the piezoelectric diaphragm 15. The inside of sound outlet hole 5 is round platform shape, and sound outlet hole 5 is provided with 1 on non-metal tube shell 4, and the round platform shape sound outlet hole 5 is located the drill way sectional area on non-metal tube shell 4 outer wall and is greater than the drill way sectional area on non-metal tube shell 4 inner wall. The inside of sound outlet 5 is oval, and sound outlet 5 is provided with 2 on non-metal pipe shell 4.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.