Packaging structure of MEMS micro galvanometer and laser radar device

Abstract

The packaging structure is characterized in that the packaging structure comprises a shell, an MEMS micro-vibrating mirror and a PCB, the MEMS micro-vibrating mirror and the PCB are arranged in the shell, the shell is provided with a light inlet hole for laser to pass through, the position of the MEMS micro-vibrating mirror is fixed through a limiting assembly, the PCB is arranged between the MEMS micro-vibrating mirror and the inner wall of the shell, and the MEMS micro-vibrating mirror is arranged in the shell. The PCB and the MEMS micro-vibrating mirror are bonded through a gold wire, and the center of the MEMS micro-vibrating mirror, the center of the PCB, the center of the limiting assembly and the center of the light inlet hole are located on the same straight line. According to the invention, the position and the movement range of the MEMS micro-vibrating mirror are limited by using the limiting assembly, so that the movement range of the MEMS micro-vibrating mirror does not exceed the displacement of tearing damage, the impact resistance of the MEMS micro-vibrating mirror can be remarkably improved, and the reliability of the MEMS micro-vibrating mirror product in severe environments such as high vibration and high explosion is ensured.

Description

Technical Field

[0001] The present invention relates to the field of MEMS device packaging, and in particular to a packaging structure of a MEMS micro-vibration mirror device and a laser radar device. Background Art

[0002] Currently, most manufacturers use a packaging method that uses a metal shell to wrap the MEMS device. The MEMS device is set inside the shell, the PCB board is placed outside the shell, the probe passes through the shell and is connected to the PCB board, and the MEMS device is electrically connected to the probe through a gold wire. This packaging structure is mainly designed for sensors such as accelerometers. Since it does not contain active moving parts, it has strong impact resistance. However, this type of MEMS device packaging structure is not suitable for MEMS micro-vibration mirrors. Because the MEMS micro-vibration mirror is a moving part, when the external impact signal energy acts on the shell, the shell will transmit the impact kinetic energy inward. After the MEMS micro-vibration mirror receives the transmitted energy, it will move. When the movement displacement of the MEMS micro-vibration mirror exceeds its maximum displacement for normal operation, it will cause the MEMS micro-vibration mirror body to tear and be damaged.

[0003] Therefore, a packaging structure is needed that can limit the maximum displacement of the MEMS micro-vibration mirror, avoid the problem of the MEMS micro-vibration mirror body tearing under over-limit operation, significantly improve the ability of MEMS micro-vibration mirror products to resist high-intensity impact, and ensure the product reliability in harsh environments such as high vibration and high explosion. Summary of the Invention

[0004] To address the above technical issues, the present invention provides a MEMS micro-vibration mirror packaging structure that utilizes a limiter assembly to restrict the position and range of motion of the MEMS micro-vibration mirror, ensuring that the mirror's range of motion does not exceed the displacement that would cause damage. Furthermore, the present invention incorporates a printed circuit board (PCB) within the packaging housing, allowing the PCB to absorb a portion of the impact kinetic energy. This solution significantly improves the MEMS micro-vibration mirror's impact resistance and ensures its reliability in harsh environments such as high vibration and high explosion.

[0005] A technical solution adopted in the present invention is:

[0006] A packaging structure for a MEMS micro-mirror comprises a housing, a MEMS micro-mirror and a PCB board disposed within the housing, the housing being provided with a light inlet for laser light to pass through, the MEMS micro-mirror being fixed in position by a limit assembly, the PCB board being disposed between the MEMS micro-mirror and the inner wall of the housing, the PCB and the MEMS micro-mirror being bonded by gold wire, and the centers of the MEMS micro-mirror, the PCB board, the limit assembly, and the light inlet being aligned on the same straight line. Existing MEMS device packaging structures are primarily designed for sensors such as accelerometers. Since they do not contain active moving parts, they have strong impact resistance. However, such MEMS device packaging structures are not suitable for MEMS micro-mirrors. Because the MEMS micro-mirror is a moving part, when external impact signal energy acts on the housing, the housing transmits the impact kinetic energy inward. After receiving the transmitted energy, the MEMS micro-mirror moves. When the movement displacement of the MEMS micro-mirror exceeds its maximum displacement for normal operation, the MEMS micro-mirror body will be torn and damaged. Therefore, the present invention designs a packaging structure specifically adapted for MEMS micro-vibration mirrors. This design utilizes a limiter assembly to restrict the position and range of motion of the MEMS micro-vibration mirror, ensuring that its range of motion does not exceed the displacement that would cause damage. This significantly improves the MEMS micro-vibration mirror's impact resistance and extends its product life. Furthermore, the present invention incorporates a PCB inside the packaging housing, allowing the PCB to absorb some of the kinetic energy of the impact.

[0007] The stopper assembly includes a first stopper, which is provided with a laser hole that matches the shape and size of the light inlet hole. The MEMS micro-vibration mirror is disposed below the first stopper. The first stopper is disposed above the MEMS micro-vibration mirror. When the MEMS micro-vibration mirror moves upward axially, it is blocked by the first stopper, and the movement of the MEMS micro-vibration mirror stops.

[0008] The MEMS micro-vibration mirror includes a base plate and a reflector located above the base plate, and the base plate and the reflector are connected by a support member; the first limiter includes a limiter plate arranged parallel to the reflector and a side wall perpendicular to the limiter plate, the laser hole is arranged in the middle of the limiter plate, a gap is provided between the lower surface of the limiter plate and the upper surface of the reflector, and a gap is provided between the inner side of the side wall and the outer edge of the reflector. Furthermore, the first limiter includes a limiter plate and a side wall structure perpendicular to the limiter plate. When the MEMS micro-vibration mirror moves upward axially, it is blocked by the limiter plate structure of the first limiter, and the movement of the MEMS micro-vibration mirror stops; when the MEMS micro-vibration mirror moves laterally, it is blocked by the side wall structure of the first limiter, and the movement of the MEMS micro-vibration mirror stops. The gap between the lower surface of the limiter plate and the upper surface of the reflector, and the gap between the inner side of the side wall and the outer edge of the reflector are the movement range of the MEMS micro-vibration mirror for upward axial movement and lateral movement.

[0009] The limiting assembly further includes a second limiter, which is located below the MEMS micro-vibration mirror. The second limiter located below the MEMS micro-vibration mirror is used to limit the downward movement of the MEMS micro-vibration mirror.

[0010] A gap is provided between the upper surface of the second stopper and the lower surface of the base plate, and the gap is the motion range of the MEMS micro-vibration mirror for downward axial movement.

[0011] The maximum value of the gap is the maximum displacement of the MEMS micro-vibration mirror when it is working normally. Generally speaking, the maximum displacement values ​​of different models of MEMS micro-vibration mirrors when working normally vary greatly. The maximum value of the gap is not specifically limited here and can be set according to the model of the MEMS micro-vibration mirror.

[0012] The shell includes an upper shell and a lower shell, the light inlet is arranged at the center of the upper shell, the cross-section of the light inlet is an inverted trapezoid, the first limiter is fixedly connected to the upper shell, the lower shell includes a cavity for placing the MEMS micro-vibration mirror and the PCB, and the second limiter is arranged on the surface of the cavity.

[0013] The upper shell is provided with a slot for accommodating the limiting plate, a portion of the side wall is located in the slot, and the remaining portion is exposed outside the slot.

[0014] The PCB board has an opening in the middle, the reflector is arranged inside the opening, and the PCB board is bonded to the upper shell and the bottom plate by soft glue.

[0015] The present invention further provides a laser radar device comprising the MEMS micro-vibration mirror packaging structure according to any one of the above claims. An incident laser is reflected by a mirror surface in the MEMS micro-vibration mirror packaging structure and then irradiates the surface of an object to be measured.

[0016] The beneficial effects of the present invention are:

[0017] The present invention provides a packaging structure for a MEMS micro-vibration mirror, which utilizes a limit assembly to limit the position and motion range of the MEMS micro-vibration mirror, so that the motion range of the MEMS micro-vibration mirror does not exceed the displacement amount of tearing damage. In addition, a PCB board is arranged inside the packaging shell, and a part of the impact kinetic energy can be absorbed by the PCB board, thereby significantly improving the impact resistance of the MEMS micro-vibration mirror and ensuring the product reliability in harsh environments such as high vibration and high explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 Schematic diagram of the packaging structure of a MEMS micro-vibration mirror provided in Example 1;

[0020] Figure 2 Schematic diagram of the structure of the MEMS micro-vibration mirror and the first limiter in Example 1, wherein the gap L is represented by the black arrows;

[0021] Figure 3 Schematic diagram of the packaging structure of a MEMS micro-vibration mirror provided in Example 2;

[0022] Figure 4 Schematic diagram of the gap in Example 2;

[0023] Figure 5 This is a schematic diagram of the movement direction of the MEMS micro-vibration mirror in Example 2.

[0024] Description of reference numerals:

[0025] 1. Housing; 11. Light inlet; 12. Upper housing; 121. Card slot; 13. Lower housing; 131. Concave cavity;

[0026] 2. MEMS micro-vibration mirror; 21. Base plate; 22. Reflector; 23. Support member;

[0027] 3. PCB board;

[0028] 4. Limiting assembly; 41. First stopper; 411. Laser hole; 412. Limiting plate; 413. Side wall; 42. Second stopper;

[0029] 5. Gold wire; 6. Glue, L represents the gap. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present invention more apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the present invention shown in and described with reference to the accompanying drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0031] Example 1

[0032] Figure 1 Schematic diagram of the packaging structure of a MEMS micro-vibration mirror provided in Example 1. Figure 2 Schematic diagram of the structure of the MEMS micro-vibration mirror and the first limiter in Example 1, where the black arrows represent the gap L. Figure 1 and Figure 2 As shown, the packaging structure of a MEMS micro-mirror provided in this embodiment 1 includes a shell 1 and a MEMS micro-mirror 2 and a PCB board 3 arranged in the shell 1. The shell 1 is provided with a light inlet 11 for the laser to pass through. The MEMS micro-mirror 2 is fixed in position by a limiting component 4. The PCB board 3 is arranged between the MEMS micro-mirror 2 and the inner wall of the shell 1. The PCB 3 is electrically connected to the MEMS micro-mirror 2 by gold wire bonding. The centers of the MEMS micro-mirror 2, the PCB board 3, the limiting component 4 and the light inlet 11 are on the same straight line. The technical solution provided in this embodiment limits the position and motion range of the MEMS micro-mirror 2 by the limiting component 4, so that the motion range of the MEMS micro-mirror 2 does not exceed the displacement of tearing damage, thereby significantly improving the impact resistance of the MEMS micro-mirror and extending the service life of the MEMS micro-mirror product. In addition, the present invention arranges the PCB board inside the packaging shell, and a part of the impact kinetic energy can be absorbed by the PCB board.

[0033] The shell 1 includes an upper shell 12 and a lower shell 13. The light inlet 11 is arranged at the center of the upper shell 12. The cross-section of the light inlet 11 is an inverted trapezoid. The first limiter 41 is fixedly connected to the upper shell 12. The lower shell 13 includes a cavity 131 for placing the MEMS micro-vibration mirror 2 and the PCB 3.

[0034] The PCB board 3 has an opening in the middle, and the reflector 22 is arranged inside the opening. The PCB board 3 is bonded to the upper shell 12 and the bottom plate 21 by soft glue 6 .

[0035] Specifically, in this embodiment, the limiting assembly 4 includes a first limiter 41, on which a laser hole 411 having a shape and size adapted to the light inlet 11 is provided, and the MEMS micro-mirror 2 is arranged below the first limiter 41. The MEMS micro-mirror 2 includes a base plate 21 and a reflector 22 located above the base plate 21, and the base plate 21 and the reflector 22 are connected by a support member 23; the first limiter 41 includes a limiting plate 412 arranged parallel to the reflector 22 and a side wall 413 perpendicular to the limiting plate 412, the laser hole 411 is arranged in the middle of the limiting plate 412, a gap L is provided between the lower surface of the limiting plate 412 and the upper surface of the reflector 22, and a gap L is provided between the inner side of the side wall 413 and the outer edge of the reflector 22. The upper shell 12 is provided with a slot 121 for accommodating the limiting plate 412 . A portion of the side wall 413 is located in the slot 121 , and the remaining portion is exposed outside the slot 121 .

[0036] When the MEMS micro-vibration mirror moves upward axially, it is blocked by the limit plate 412 structure of the first limiter 41, and the movement of the MEMS micro-vibration mirror 2 stops; when the MEMS micro-vibration mirror moves laterally, it is blocked by the side wall 413 structure of the first limiter 41, and the movement of the MEMS micro-vibration mirror 2 stops. The gap L between the lower surface of the limit plate and the upper surface of the reflector, and the gap L between the inner side of the side wall and the outer edge of the reflector are the movement range of the MEMS micro-vibration mirror for upward axial movement and lateral movement. The maximum value of the gap L is the maximum displacement of the MEMS micro-vibration mirror when it is working normally. In this embodiment, the gap is 0.2 mm. Generally speaking, the maximum displacement values ​​of different models of MEMS micro-vibration mirrors when working normally are quite different. The maximum value of the gap is not specifically limited here and can be set according to the model of the MEMS micro-vibration mirror.

[0037] Example 2

[0038] This embodiment provides a packaging structure of a MEMS micro-vibration mirror, which is basically the same as the packaging structure in Example 1, except that this embodiment further improves the limiting component.

[0039] like Figure 3 and Figure 4As shown, the limit assembly 4 also includes a second limiter 42, which is located below the MEMS micro-mirror 2 and is placed on the surface 131 of the cavity. A gap L is provided between the upper surface of the second limiter 42 and the lower surface of the base plate 21, and the maximum value of the gap L is the maximum displacement of the MEMS micro-mirror 2 when it is working normally. The first limiter 41 in Example 1 is provided above the MEMS micro-mirror 2, which can limit the upward axial movement and lateral movement range of the MEMS micro-mirror 2. In this embodiment, the second limiter 42 is provided below the MEMS micro-mirror 2, which can also limit the downward axial movement range of the MEMS micro-mirror 2, further improving the impact resistance of the MEMS micro-mirror and ensuring the reliability of the MEMS micro-mirror product in harsh environments such as high vibration and high explosion.

[0040] Figure 5 This is a schematic diagram of the movement direction of the MEMS micro-vibration mirror in Example 2, as shown in Figure 5 As shown, when the MEMS micro-vibration mirror moves upward axially, it is blocked by the limit plate 412 structure of the first limiter 41, and the movement of the MEMS micro-vibration mirror 2 stops; when the MEMS micro-vibration mirror moves laterally, it is blocked by the side wall 413 structure of the first limiter 41, and the other parts are blocked by connecting structures such as glue, and the movement of the MEMS micro-vibration mirror 2 stops; when the MEMS micro-vibration mirror moves downward axially, it is blocked by the second limiter 42, and the movement of the MEMS micro-vibration mirror 2 stops.

[0041] The present invention further provides a laser radar device comprising a MEMS micro-vibration mirror package structure according to any one of the preceding claims. Incident laser light is reflected by a mirror surface in the MEMS micro-vibration mirror package structure and then irradiates the surface of an object to be measured, thereby detecting the object to be measured.

[0042] In addition, it should be noted that, in this specification, "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0043] It should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A packaging structure of a MEMS micro-vibration mirror, characterized in that: The invention comprises a shell (1), a MEMS micro-vibration mirror (2) and a PCB (3) arranged in the shell (1); the shell (1) is provided with a light inlet (11) for laser light to pass through; the MEMS micro-vibration mirror (2) is fixed in position by a position-limiting assembly (4); the PCB (3) is arranged between the MEMS micro-vibration mirror (2) and the inner wall of the shell (1); the PCB (3) and the MEMS micro-vibration mirror (2) are bonded by a gold wire (5); and the centers of the MEMS micro-vibration mirror (2), the PCB (3), the position-limiting assembly (4) and the light inlet (11) are on the same straight line.

2. The packaging structure of a MEMS micro-vibration mirror according to claim 1, characterized in that: The limiting assembly (4) comprises a first limiter (41), the first limiter (41) being provided with a laser hole (411) having a shape and size adapted to the light inlet hole (11), and the MEMS micro-vibration mirror (2) being arranged below the first limiter (41).

3. The packaging structure of a MEMS micro-mirror according to claim 2, characterized in that: The MEMS micro-vibration mirror (2) comprises a base plate (21) and a reflector (22) located above the base plate (21), wherein the base plate (21) and the reflector (22) are connected via a support member (23); the first stopper (41) comprises a limit plate (412) arranged parallel to the reflector (22) and a side wall (413) perpendicular to the limit plate (412); the laser hole (411) is arranged in the middle of the limit plate (412); a gap is provided between the lower surface of the limit plate (412) and the upper surface of the reflector (22); and a gap is provided between the inner side of the side wall (413) and the outer edge of the reflector (22).

4. The MEMS micro-mirror packaging structure according to claim 3, wherein: The limiting assembly (4) further comprises a second limiter (42), and the second limiter (42) is located below the MEMS micro-vibration mirror (2).

5. The packaging structure of a MEMS micro-vibration mirror according to claim 4, characterized in that: A gap is provided between the upper surface of the second stopper (42) and the lower surface of the bottom plate (21).

6. The MEMS micro-mirror packaging structure according to claim 3 or 5, characterized in that: The maximum value of the gap is the maximum displacement of the MEMS micro-vibration mirror (2) when it is working normally.

7. The packaging structure of a MEMS micro-vibration mirror according to claim 4, characterized in that: The housing (1) comprises an upper housing (12) and a lower housing (13); the light inlet (11) is arranged at the center of the upper housing (12); the cross section of the light inlet (11) is an inverted trapezoid; the first stopper (41) is fixedly connected to the upper housing (12); the lower housing (13) comprises a concave cavity (131) for placing the MEMS micro-vibration mirror (2) and the PCB (3); and the second stopper (42) is arranged on the surface of the concave cavity (131).

8. The MEMS micro-mirror packaging structure according to claim 7, characterized in that: The upper shell (12) is provided with a slot (121) for accommodating the limiting plate (412); a portion of the side wall (413) is located in the slot (121), and the remaining portion is exposed outside the slot (121).

9. The MEMS micro-mirror packaging structure according to claim 7, wherein: The PCB board (3) has an opening in the middle, the reflector (22) is arranged inside the opening, and the PCB board (3) is bonded to the upper shell (12) and the bottom plate (21) by means of soft glue (6).

10. A laser radar device, characterized in that: The MEMS micro-vibration mirror packaging structure comprises any one of claims 1 to 9.

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