High-frequency sensor for close-range detection

Abstract

The present invention relates to a high-frequency sensor suitable for short-range detection, comprising a first shell, a piezoelectric ceramic piece and a first matching layer. The piezoelectric ceramic piece is arranged in the first shell, and the piezoelectric ceramic piece is connected to one end face of the first matching layer. The first matching layer is embedded in the first shell, and the other end of the first matching layer protrudes out of the first end of the first shell. In the above-mentioned high-frequency sensor suitable for short-range detection, after the first matching layer is embedded in the first shell, on the one hand, the first matching layer is embedded and fixed in the first shell, and the entire high-frequency sensor suitable for short-range detection has a relatively stable structure; on the other hand, since the end of the first matching layer protrudes out of the first end of the first shell, the binding force of the first shell on the surrounding areas of the first matching layer can be reduced, which can greatly reduce the phenomenon of insufficient echo signals. That is, it can be suitable for short-range detection and has a good echo signal.

Description

Technical Field

[0001] The present invention relates to a sensor, in particular to a high-frequency sensor suitable for short-range detection. Background Art

[0002] With the rise of smart homes, an increasing number of high-frequency sensors are being used for close-range detection (2cm-5cm) in smart home products. However, traditional high-frequency sensors often suffer from the following issues: Their residual vibration is relatively large, and there is no effective way to suppress it, resulting in a large blind spot and failing to meet the market's close-range detection requirements. Alternatively, their residual vibration is small, but the echo signal is too weak to be recognized. Summary of the Invention

[0003] Based on this, it is necessary to overcome the defects of the existing technology and provide a high-frequency sensor suitable for short-range detection, which can be suitable for short-range detection and has a good echo signal.

[0004] The technical solution is as follows: A high-frequency sensor suitable for close-range detection includes: a first shell, a piezoelectric ceramic piece and a first matching layer. The piezoelectric ceramic piece is arranged in the first shell, the piezoelectric ceramic piece is connected to one end surface of the first matching layer, the first matching layer is embedded in the first shell, and the other end of the first matching layer protrudes outside the first end of the first shell.

[0005] In the aforementioned high-frequency sensor for close-range detection, after the first matching layer is embedded in the first housing, the first matching layer is fixedly mounted in the first housing, making the entire high-frequency sensor for close-range detection more stable. Furthermore, since the end of the first matching layer protrudes beyond the first end of the first housing, the binding force of the first housing on the surrounding area of the first matching layer is reduced, thereby significantly reducing the phenomenon of insufficient echo signals. In other words, the sensor is suitable for close-range detection while providing a good echo signal.

[0006] In one embodiment, the thickness of the portion of the first matching layer protruding from the first shell is T1, λ / 8≤T1≤λ / 4, where λ is the ultrasonic wavelength; the density of the first matching layer is P1, 0.5 g / cm 3 ≤P1≤0.7g / cm 3 .

[0007] In one embodiment, the high-frequency sensor suitable for close-range detection further includes a second matching layer, and the second matching layer is coated on the first matching layer.

[0008] In one embodiment, the thickness of the second matching layer is T2, T1 / 4≤T2≤T1; the density of the second matching layer is P2, 0.7 g / cm 3 ≤P2≤1.1g / cm 3 .

[0009] In one embodiment, the high-frequency sensor suitable for close-range detection also includes a damping layer, a transfer PCB board, a first potting compound, an external wire and two internal wires; the damping layer is arranged between the transfer PCB board and the piezoelectric ceramic piece, the transfer PCB board is respectively connected to the positive and negative electrodes of the piezoelectric ceramic piece through the two internal wires, and the transfer PCB board is electrically connected to the external device through the external wire; the first potting compound is injected into the first shell through the second end of the first shell, and the first potting compound is connected to the transfer PCB board.

[0010] In one embodiment, the inner wall of the first shell is provided with a first step surface, and one end of the first matching layer is in conflict with the first step surface.

[0011] In one embodiment, the high-frequency sensor suitable for close-range detection further includes a second shell and an elastic sleeve; the second shell is arranged outside the first shell, and the elastic sleeve is arranged between the first shell and the second shell; the end face of the first end of the first shell, the end face of the first end of the second shell and the end face of the first end of the elastic sleeve are on the same plane, and the end of the first matching layer protrudes from the plane.

[0012] In one embodiment, the elastic sleeve is a rubber sleeve or a silicone sleeve; the hardness of the elastic sleeve is 25 shoreA-50 shoreA.

[0013] In one embodiment, a second step surface and a third step surface are provided on the inner wall of the second shell, the end surface of the second end of the elastic sleeve is in contact with the second step surface, and the end surface of the second end of the first shell is in contact with the third step surface.

[0014] In one embodiment, the high-frequency sensor suitable for close-range detection further includes a second potting compound, which is injected into the second shell through the second end of the second shell, and the second potting compound is connected to the second end of the first shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of a high-frequency sensor suitable for close-range detection according to an embodiment of the present invention;

[0016] Figure 2This is a schematic diagram of the specific structure of a high-frequency sensor suitable for close-range detection according to an embodiment of the present invention;

[0017] Figure 3 for Figure 2 Schematic diagram of the enlarged structure at A;

[0018] Figure 4 This is a schematic structural diagram of a high-frequency sensor suitable for close-range detection according to another embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of the specific structure of a high-frequency sensor suitable for close-range detection according to another embodiment of the present invention.

[0020] Reference numerals:

[0021] 10. First shell; 11. First stepped surface; 20. Piezoelectric ceramic piece; 30. First matching layer; 40. Second matching layer; 50. Damping layer; 60. Transfer PCB board; 70. First potting compound; 81. External conductor; 82. Internal conductor; 90. Second shell; 91. Elastic sleeve; 92. Second stepped surface; 93. Third stepped surface; 94. Second potting compound. DETAILED DESCRIPTION

[0022] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0024] In the description of the present invention, it should be understood that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be intermediate elements. On the contrary, when an element is said to be "directly" connected to another element, there are no intermediate elements.

[0025] To be suitable for close-range detection, a typical high-frequency sensor consists of a plastic housing, a piezoelectric ceramic disc mounted within the housing, and a first matching layer. The piezoelectric ceramic disc is bonded to one side of the first matching layer, then embedded within the housing, with the other side of the first matching layer flush with the housing. However, when a high-frequency sensor is mounted flush with the housing, the housing exerts a binding force on the surrounding area of the first matching layer, resulting in insufficient echo signals after assembly.

[0026] In one embodiment, see Figures 1 to 3 A high-frequency sensor suitable for close-range detection includes a first housing 10, a piezoelectric ceramic disc 20, and a first matching layer 30. The piezoelectric ceramic disc 20 is disposed within the first housing 10 and is connected to one end surface of the first matching layer 30. The first matching layer 30 is embedded within the first housing 10, with the other end of the first matching layer 30 protruding beyond the first end of the first housing 10.

[0027] In the high-frequency sensor for close-range detection described above, after the first matching layer 30 is embedded in the first housing 10, the first matching layer 30 is embedded and fixed in the first housing 10, making the entire high-frequency sensor for close-range detection more stable. Furthermore, since the end of the first matching layer 30 protrudes beyond the first end of the first housing 10, the binding force of the first housing 10 on the surrounding area of the first matching layer 30 is reduced, thereby significantly reducing the phenomenon of insufficient echo signals. In other words, the sensor is suitable for close-range detection while providing a good echo signal.

[0028] Further, see Figures 1 to 3 The thickness of the portion of the first matching layer 30 protruding from the first housing 10 is T1, where λ / 8 ≤ T1 ≤ λ / 4, where λ is the ultrasonic wavelength. This reduces the binding force of the first housing 10 on the periphery of the first matching layer 30, significantly reducing the phenomenon of insufficient echo signals. This makes it suitable for close-range detection while providing a good echo signal. Furthermore, this saves material for the first matching layer 30, eliminating the need to increase its thickness.

[0029] In addition, specifically, the density of the first matching layer 30 is P1, 0.5 g / cm 3 ≤P1≤0.7g / cm 3 At this density, the first matching layer 30 has better elasticity, can achieve better echo signals, and has higher sensitivity.

[0030] In one embodiment, see Figures 1 to 3The high-frequency sensor for close-range detection further includes a second matching layer 40. The second matching layer 40 is coated on the first matching layer 30. By controlling the thickness of the second matching layer 40, the residual vibration of the product can be adjusted, thereby minimizing the residual vibration of the high-frequency sensor for close-range detection.

[0031] Further, see Figures 1 to 3 The thickness of the second matching layer 40 is T2, T1 / 4≤T2≤T1. In addition, the density of the second matching layer 40 is P2, 0.7g / cm 3 ≤P2≤1.1g / cm 3 In this way, the aftershock of the high-frequency sensor suitable for close-range detection can be reduced, and the performance of the high-frequency sensor suitable for close-range detection can be improved.

[0032] In one embodiment, see Figure 2 and Figure 3 The high-frequency sensor for close-range detection also includes a damping layer 50, a transfer PCB 60, a first potting compound 70, an external conductor 81, and two internal conductors 82. The damping layer 50 is disposed between the transfer PCB 60 and the piezoelectric ceramic 20. The transfer PCB 60 is connected to the positive and negative electrodes of the piezoelectric ceramic 20 via the two internal conductors 82. The transfer PCB 60 is electrically connected to an external device via the external conductors 81. Thus, the transfer PCB 60 electrically connects the external device to the piezoelectric ceramic 20.

[0033] Also, see Figure 2 and Figure 3 The first potting compound 70 is injected into the first housing 10 through the second end of the first housing 10, and the first potting compound 70 is connected to the transfer PCB 60. This ensures that the transfer PCB 60, the damping layer 50, the piezoelectric ceramic 20, and the first matching layer 30 are securely mounted within the first housing 10. Furthermore, the damping layer 50 minimizes the amount of vibration transmitted from the piezoelectric ceramic 20 to the transfer PCB 60, thereby increasing the detection sensitivity of the echo signal and enhancing product performance.

[0034] Specifically, see Figure 2 and Figure 3One end surface of the damping layer 50 is tightly bonded to the transfer PCB 60, while the outer wall of the damping layer 50 is tightly bonded to the inner wall of the first housing 10. The other end surface of the damping layer 50 is tightly bonded to the first matching layer 30, and the piezoelectric ceramic 20 is embedded in the damping layer 50. This arrangement reduces residual vibrations of the product while minimizing the amount of vibration transmitted from the piezoelectric ceramic 20 to the transfer PCB 60. This results in a high-frequency sensor suitable for close-range detection with high performance.

[0035] In one embodiment, see Figure 2 and Figure 3 The inner wall of the first housing 10 is provided with a first stepped surface 11, and one end of the first matching layer 30 abuts against the first stepped surface 11. This ensures that the first matching layer 30 is securely positioned and installed within the first housing 10. Specifically, the outer diameter of the first matching layer 30 is slightly larger than the inner diameter of the first housing 10. This allows the outer wall of the first matching layer 30 to fit tightly with the inner wall of the first housing 10, ensuring a secure installation within the first housing 10.

[0036] In one embodiment, see Figure 4 and Figure 5 The high-frequency sensor suitable for close-range detection also includes a second housing 90 and an elastic housing 91. The second housing 90 is mounted outside the first housing 10, and the elastic housing 91 is positioned between the first and second housings 10, 90. The end faces of the first end of the first housing 10, the first end of the second housing 90, and the first end of the elastic housing 91 are located on the same plane, with the end of the first matching layer 30 protruding from the plane. The elastic housing 91 can be, for example, a rubber or silicone housing, and is not limited here. In this manner, the first housing 10 is restrained within the wall of the second housing 90 by the elastic housing 91. The second housing 90 securely secures the elastic housing 91 and the first housing 10, reducing the residual vibration of the first housing 10 and improving product performance. Furthermore, the second housing 90 compresses the elastic housing 91, causing it to exert a circumferential, centripetal binding force on the first housing 10. In addition, a certain volume gap is left between the outer wall of the elastic sleeve 91 and the inner wall of the second shell 90 to allow compression deformation of the elastic sleeve 91 , and the deformation amount of the elastic sleeve 91 is between 1% and 5%.

[0037] In a specific embodiment, see Figure 4 and Figure 5The elastic sleeve 91 is a rubber sleeve with a hardness of 25 shoreA to 50 shoreA. This moderate hardness of the elastic sleeve 91 effectively reduces the residual vibration of high-frequency sensors used for short-range detection. While a lower or higher hardness of the elastic sleeve 91 can still reduce the residual vibration of high-frequency sensors used for short-range detection, the effect is slightly less than when the elastic sleeve 91 has a hardness of 25 shoreA to 50 shoreA.

[0038] In one embodiment, see Figure 4 and Figure 5 The first shell 10 and the second shell 90 are both plastic shells, and can also be metal shells or plastic shells, which are not limited here.

[0039] Further, see Figure 4 and Figure 5 , a second stepped surface 92 and a third stepped surface 93 are provided on the inner wall of the second shell 90. The end surface of the second end of the elastic sleeve 91 is in conflict with the second stepped surface 92, and the end surface of the second end of the first shell 10 is in conflict with the third stepped surface 93. In this way, after the first shell 10 is installed in the second shell 90, the end surface of the second end of the first shell 10 is in conflict with the third stepped surface 93. After the elastic sleeve 91 is installed in the second shell 90, the elastic sleeve 91 is not only sleeved on the outside of the first shell 10, but also sleeved on the inside of the second shell 90. The end surface of the second end of the elastic sleeve 91 is also in conflict with the second stepped surface 92. In this way, the second shell 90, the first shell 10 and the elastic sleeve 91 can be quickly assembled, and the stability after assembly is good.

[0040] In one embodiment, see Figure 4 and Figure 5 The high-frequency sensor for close-range detection further includes a second potting compound 94. The second potting compound 94 is injected into the second housing 90 through the second end of the second housing 90. The second potting compound 94 is connected to the second end of the first housing 10. Thus, the second potting compound 94 securely bonds the first housing 10, the second housing 90, and the elastic sleeve 91 together, providing improved stability.

[0041] As an optional solution, to ensure a secure connection between the first housing 10 and the second housing 90, adhesive is provided on the inner wall of the second housing 90 between the second stepped surface 92 and the third stepped surface 93. The second end of the first housing 10 is bonded and fixed to the second housing 90 via the adhesive. Furthermore, the second end surface of the first housing 10 abuts against the third stepped surface 93. In this way, the second end of the first housing 10 is securely positioned within the second housing 90.

[0042] Further, see Figure 4 and Figure 5 The inner wall portion between the second step surface 92 and the third step surface 93 of the second shell 90 corresponds to the position of the adapter PCB board 60 in the first shell 10. In other words, the adapter PCB board 60 is correspondingly arranged at the second end of the first shell 10, so that it can be installed in the first shell 10 more stably.

[0043] Further, see Figure 4 and Figure 5 The inner wall portion between the second stepped surface 92 and the first end face of the second housing 90 is correspondingly mounted outside the elastic sleeve 91 and positioned to correspond to the positions of the damping layer 50, the piezoelectric ceramic 20, and the first matching layer 30 within the first housing 10. Thus, during vibration of the piezoelectric ceramic 20, the elastic sleeve 91, mounted outside the first housing 10 and therefore positioned outside the damping layer 50, the piezoelectric ceramic 20, and the first matching layer 30, effectively provides vibration reduction. This results in a low residual vibration for the high-frequency sensor suitable for close-range detection, resulting in high product performance.

[0044] As an optional solution, in order to ensure that the elastic sleeve 91 is more firmly sleeved on the outer wall of the first shell 10, adhesive is provided on the outer wall of the first shell 10, and the elastic sleeve 91 is bonded and fixed to the outer wall of the first shell 10 by the adhesive.

[0045] As an optional solution, the outer wall of the elastic sleeve 91 can also be glued and fixed to the inner wall of the second shell 90. Alternatively, the outer diameter of the outer wall of the elastic sleeve 91 is larger than the inner diameter of the second shell 90, so that the elastic sleeve 91 can be more firmly arranged in the second shell 90.

[0046] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0047] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A high-frequency sensor suitable for close-range detection, characterized in that: include: A first shell, a piezoelectric ceramic sheet, and a first matching layer. The piezoelectric ceramic sheet is disposed within the first shell and is connected to one end surface of the first matching layer. The first matching layer is embedded within the first shell, and the other end of the first matching layer protrudes beyond the first end of the first shell. The thickness of the portion of the first matching layer protruding beyond the first shell is T1, λ / 8≤T1≤λ / 4, where λ is the ultrasonic wavelength. The density of the first matching layer is P1, 0.5 g / cm 3 ≤P1≤0.7g / cm 3 ; The inner wall of the first shell is provided with a first step surface, one end of the first matching layer is in conflict with the first step surface, and the outer wall of the first matching layer is tightly fitted with the inner wall of the first shell; the high-frequency sensor suitable for close-range detection also includes a second matching layer, the second matching layer is coated on the first matching layer, and the thickness of the second matching layer is T2, T1 / 4≤T2≤T1.

2. The high-frequency sensor suitable for close-range detection according to claim 1, characterized in that: The density of the second matching layer is P2, 0.7 g / cm 3 ≤P2≤1.1g / cm 3 .

3. The high-frequency sensor suitable for close-range detection according to claim 1 or 2, characterized in that: It also includes a damping layer, a transfer PCB board, a first potting compound, an external wire and two internal wires; the damping layer is arranged between the transfer PCB board and the piezoelectric ceramic sheet, the transfer PCB board is respectively connected to the positive and negative electrodes of the piezoelectric ceramic sheet through the two internal wires, and the transfer PCB board is electrically connected to the external device through the external wires; the first potting compound is injected into the first shell through the second end of the first shell, and the first potting compound is connected to the transfer PCB board.

4. The high-frequency sensor suitable for close-range detection according to claim 3, characterized in that: One end surface of the damping layer is tightly fitted with the transfer PCB board, the outer wall of the damping layer is tightly fitted with the inner wall of the first shell, the other end surface of the damping layer is tightly fitted with the first matching layer, and the piezoelectric ceramic piece is embedded in the damping layer.

5. The high-frequency sensor suitable for close-range detection according to claim 3, characterized in that: It also includes a second shell and an elastic sleeve; the second shell is arranged outside the first shell, and the elastic sleeve is arranged between the first shell and the second shell; the end face of the first end of the first shell, the end face of the first end of the second shell and the end face of the first end of the elastic sleeve are on the same plane, and the end of the first matching layer protrudes from the plane.

6. The high-frequency sensor suitable for close-range detection according to claim 5, characterized in that: The elastic sleeve is a rubber sleeve or a silicone sleeve; the hardness of the elastic sleeve is 25 shoreA-50 shoreA.

7. The high-frequency sensor suitable for close-range detection according to claim 5, characterized in that: The inner wall of the second shell is provided with a second step surface and a third step surface. The end surface of the second end of the elastic sleeve is in contact with the second step surface, and the end surface of the second end of the first shell is in contact with the third step surface.

8. The high-frequency sensor suitable for close-range detection according to claim 7, characterized in that: The inner wall portion between the second stepped surface of the second shell and the end surface of the first end is correspondingly sleeved outside the elastic sleeve and arranged correspondingly to the positions of the damping layer, the piezoelectric ceramic sheet and the first matching layer in the first shell.

9. The high-frequency sensor suitable for close-range detection according to claim 5, characterized in that: It also includes a second potting glue, which is injected into the second shell through the second end of the second shell, and the second potting glue is connected to the second end of the first shell.

10. The high-frequency sensor suitable for close-range detection according to claim 5, characterized in that: The first shell and the second shell are both rubber shells, metal shells or plastic shells.

Images