Ultrasonic sensor based on integration of transmitting and receiving

Abstract

The utility model discloses an ultrasonic sensor based on integration of transmitting and receiving, which comprises a substrate, the substrate is provided with a front surface and a back surface which are opposite to each other, the front surface of the substrate is sequentially provided with a bottom electrode and a piezoelectric layer in a laminated manner, and the front surface of the substrate comprises a top electrode arranged on the piezoelectric layer far away from the surface of the substrate; the top electrode comprises an inner-layer electrode, a middle-layer electrode arranged around the inner-layer electrode and an outer-layer electrode arranged around the middle-layer electrode so as to transmit and receive ultrasonic signals; by arranging the bottom electrode, the piezoelectric layer, the inner-layer electrode, the middle-layer electrode and the outer-layer electrode, signal transmitting and signal receiving of the device are integrated, the diversity of working frequencies is improved, the frequency range is expanded, and the equipment size and the cost can be reduced while the resolution ratio is ensured.

Description

Technical Field

[0001] The utility model specifically relates to an ultrasonic sensor based on integration of emission and reception. Background Art

[0002] Ultrasound technology and products have developed rapidly in recent years. Traditional ultrasound products and applications have primarily focused on medical imaging, such as fetal ultrasound, human body scans, and endoscopic imaging. Driven by the rapid development of ultrasound applications, medical ultrasound products are also moving towards miniaturization, portability, and handheld applications. Semiconductor MEMS (microelectromechanical system) ultrasound sensors, benefiting from the high precision and high yield of CMOS processes, are the most promising technology for achieving high-resolution medical ultrasound array sensors. MEMS technology allows for the manufacture of significantly smaller medical devices or medical device components. Piezoelectric micromachined ultrasonic transducers (PMUTs) are a type of MEMS-based transducer technology.

[0003] Traditional PMUTs are usually single-frequency, with a narrow operating frequency and low transducer design flexibility. In addition, to achieve high sensitivity, a very high bias voltage must be applied during operation, posing a safety risk. In addition, traditional PMUTs only serve as transmitters or receivers. Medical device probes must have both transmitters and receivers, making the device area larger. To this end, we propose an ultrasonic sensor based on an integrated transmitter and receiver. Utility Model Content

[0004] The present invention aims to solve the problems raised in the background technology. The purpose of one or more embodiments of this specification is to propose an ultrasonic sensor based on integrated transmission and reception, which integrates the transmission signal and the reception signal into one, ensures the resolution while reducing the device size and reducing the cost.

[0005] To achieve the above objectives, the present invention provides the following technical solutions: an ultrasonic sensor based on integrated transmission and reception, comprising: a substrate having a front surface and a back surface opposite to each other, a bottom electrode and a piezoelectric layer stacked in sequence on the front surface of the substrate, and a top electrode disposed on the piezoelectric layer away from the substrate surface;

[0006] The top electrode includes an inner electrode, a middle electrode arranged around the inner electrode, and an outer electrode arranged around the middle electrode, so as to transmit and receive ultrasonic signals.

[0007] Preferably, the substrate is a silicon wafer substrate or an SOI substrate.

[0008] Preferably, the middle electrode has a second-order frequency of the inner electrode, and the outer electrode has a fourth-order frequency of the inner electrode.

[0009] Preferably, the inner electrode is used to transmit ultrasonic signals, and the middle electrode and the outer electrode are used together to receive ultrasonic signals.

[0010] Preferably, the inner electrode is used to receive ultrasonic signals, and the middle electrode and the outer electrode are used together to transmit ultrasonic signals.

[0011] Preferably, the inner electrode has a circular cross section.

[0012] Preferably, the middle-layer electrodes are a plurality of arc-shaped blocks arranged in a ring array.

[0013] Preferably, the outer electrode is also a plurality of arc-shaped blocks arranged in a ring array, and the inner diameter of the outer electrode is larger than the outer diameter of the middle electrode.

[0014] Preferably, a groove having the same shape as the top electrode is etched on the front surface of the substrate.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] This patent avoids the problem of separating the transmitting end and the receiving end, which is inconvenient to use and has a single frequency, by providing a bottom electrode, a piezoelectric layer, an inner electrode, a middle electrode and an outer electrode. The device transmits and receives signals in one piece, which improves the diversity of the working frequency, expands the frequency range, and can reduce the size of the equipment and cut costs while ensuring the resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of the utility model;

[0018] Figure 2 This is a schematic diagram of the explosion structure of the utility model;

[0019] Figure 3 This is a schematic diagram of the top electrode structure of the present utility model.

[0020] In the figure: 1, substrate; 2, bottom electrode; 3, piezoelectric layer; 4, top electrode; 41, inner electrode; 42, middle electrode; 43, outer electrode. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] Example 1

[0023] See also Figure 1-Figure 3 The present invention provides a technical solution: an ultrasonic sensor based on integrated transmission and reception, comprising: a substrate 1, the substrate 1 having a front surface and a back surface opposite to each other, a bottom electrode 2 and a piezoelectric layer 3 stacked in sequence on the front surface of the substrate 1, and a top electrode 4 arranged on the piezoelectric layer 3 away from the surface of the substrate 1;

[0024] The top electrode 4 includes an inner electrode 41, a middle electrode 42 arranged around the inner electrode 41, and an outer electrode 43 arranged around the middle electrode 42, so as to transmit and receive ultrasonic signals. In the transmitting mode, the top electrode 4 receives the excitation voltage from the bottom circuit, causing the piezoelectric layer 3 to produce a piezoelectric effect, thereby transmitting an ultrasonic signal. In the receiving mode, the top electrode 4 receives the ultrasonic signal reflected from the external environment, and converts the mechanical vibration into an electrical signal, which is output to the sensor circuit for processing and analysis.

[0025] In this embodiment, preferably, the substrate 1 is a silicon wafer substrate or an SOI substrate. The SOI substrate is short for silicon-on-insulator substrate and has good mechanical support and stability.

[0026] In this embodiment, preferably, the middle electrode 42 is the second-order frequency of the inner electrode 41, and the outer electrode 43 is the fourth-order frequency of the inner electrode 41. By configuring electrodes at different levels, it is easy to respond to and detect vibrations of different frequencies.

[0027] In this embodiment, preferably, the inner electrode 41 is used to transmit ultrasonic signals, and the middle electrode 42 and the outer electrode 43 are used together to receive ultrasonic signals.

[0028] In this embodiment, preferably, the inner electrode 41 is used to receive ultrasonic signals, and the middle electrode 42 and the outer electrode 43 are used together to transmit ultrasonic signals.

[0029] In this embodiment, preferably, the cross section of the inner electrode 41 is circular.

[0030] In this embodiment, preferably, the middle electrode 42 is a plurality of arc-shaped blocks arranged in a ring array.

[0031] In this embodiment, preferably, the outer electrode 43 is also a plurality of arc-shaped blocks arranged in a ring array, and the inner diameter of the outer electrode 43 is larger than the outer diameter of the middle electrode 42, so as to facilitate better response and detection effects.

[0032] In this embodiment, preferably, a groove having the same shape as the top electrode 4 is etched on the front side of the substrate 1. During etching, the front side of the substrate 1 within the longitudinal projection area of ​​the top electrode 4 is etched away, and a cavity that does not penetrate the substrate 1 is opened on the back side of the substrate 1 to facilitate better vibration transmission of ultrasonic waves.

[0033] The operating principle of this embodiment is as follows: the inner electrode 41 of the top electrode 4 serves as the ultrasonic signal receiver, while the middle electrode 42 and outer electrode 43 serve as the ultrasonic signal transmitter. This integrated transmission and reception replaces the traditional two-chip transmitter and receiver. This reduces the device size while maintaining high resolution. Specifically, applying a 50kHz excitation voltage to the inner electrode 41, a 100kHz excitation voltage to the middle electrode 42, and a 200kHz excitation voltage to the outer electrode 43 provides better feedback of depth information.

[0034] Example 2

[0035] See also Figure 1-Figure 3 The technical solution of this embodiment is the same as that of embodiment 1.

[0036] The working principle of this embodiment: the inner electrode 41 in the top electrode 4 proposed in this embodiment serves as the transmitting end of the ultrasonic signal, and the middle electrode 42 and the outer electrode 43 serve as the receiving end of the ultrasonic signal. The nonlinearity of the inner electrode 41 is excited by a single-frequency excitation voltage with a frequency of 50kHz to generate high-order harmonics with a frequency of 100kHz-200kHz, thereby further reducing costs.

[0037] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultrasonic sensor based on integrated transmission and reception, comprising: A substrate (1), the substrate (1) having a front side and a back side opposite to each other, the front side of the substrate (1) being provided with a bottom electrode (2) and a piezoelectric layer (3) stacked in sequence, and characterized in that the substrate (1) comprises a top electrode (4) arranged on a surface of the piezoelectric layer (3) away from the substrate (1); The top electrode (4) comprises an inner electrode (41), a middle electrode (42) arranged around the inner electrode (41), and an outer electrode (43) arranged around the middle electrode (42) for transmitting and receiving ultrasonic signals.

2. The ultrasonic sensor based on integrated transmission and reception according to claim 1, characterized in that: The substrate (1) is a silicon wafer substrate or an SOI substrate.

3. The ultrasonic sensor based on integrated transmission and reception according to claim 1, characterized in that: The middle electrode (42) has a second-order frequency of the inner electrode (41), and the outer electrode (43) has a fourth-order frequency of the inner electrode (41).

4. The ultrasonic sensor based on integrated transmission and reception according to claim 1, characterized in that: The inner electrode (41) is used to transmit ultrasonic signals, and the middle electrode (42) and the outer electrode (43) are used together to receive ultrasonic signals.

5. The ultrasonic sensor based on integrated transmission and reception according to claim 1, characterized in that: The inner electrode (41) is used for receiving ultrasonic signals, and the middle electrode (42) and the outer electrode (43) are used together for transmitting ultrasonic signals.

6. The ultrasonic sensor based on integrated transmission and reception according to claim 1, characterized in that: The inner electrode (41) has a circular cross section.

7. The ultrasonic sensor based on integrated transmission and reception according to claim 1, characterized in that: The middle layer electrodes (42) are a plurality of arc-shaped blocks arranged in a ring array.

8. The ultrasonic sensor based on integrated transmission and reception according to claim 7, characterized in that: The outer electrode (43) is also a plurality of arc-shaped blocks arranged in a ring array, and the inner diameter of the outer electrode (43) is larger than the outer diameter of the middle electrode (42).

9. The ultrasonic sensor based on integrated transmission and reception according to claim 1, characterized in that: A groove having the same shape as the top electrode (4) is etched on the front surface of the substrate (1).

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