Piezoelectrically actuated MEMS mirror

Abstract

The application belongs to the field of semiconductor devices, and particularly relates to a piezoelectric driving MEMS mirror, which comprises a substrate, a mirror located in a cavity, and a driving structure comprising a first driving block, a second driving block, a third driving block and a fourth driving block, wherein the first driving block, the second driving block, the third driving block and the fourth driving block are fixedly connected with the inner wall of the cavity of the substrate, the first driving block is connected with a flexible rod through a first flexible connecting rod, the second driving block is connected with the flexible rod through a second flexible connecting rod, the third driving block is connected with the flexible rod through a third flexible connecting rod, the fourth driving block is connected with the flexible rod through a fourth flexible connecting rod, and the flexible rod is connected with the mirror. The piezoelectric driving MEMS mirror has a small volume of the driving block close to the mirror, thereby wrapping the center mirror, and through the lever principle, the device area is reduced while the driving force is maintained.

Description

Technical Field

[0001] One or more embodiments of this specification relate to the field of semiconductor devices, and more particularly, to a piezoelectrically driven MEMS mirror. Background Art

[0002] MEMS mirrors can be used in applications requiring optical path control, such as optical scanners, head-up displays (HUDs), and lidar. Traditional electrostatically driven MEMS mirrors use a comb-like structure to achieve electromechanical conversion. Some of the teeth are fixed, while others are movable. There is a very small gap between the fixed and movable teeth. Electrical excitation between the fixed and movable teeth causes the mirror to rotate angularly.

[0003] However, the driving force of electrostatic actuation is related to the overlapping area between the fixed and movable comb teeth. When the movable comb teeth deflect with the reflector, the overlapping area between the fixed and movable comb teeth decreases, resulting in a decrease in driving force. Therefore, due to the limitations of the drive structure, electrostatically driven MEMS mirrors cannot provide large-angle deflection.

[0004] In summary, the present application proposes a piezoelectrically driven MEMS mirror to solve the above-mentioned problems. Summary of the Invention

[0005] 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 provide a piezoelectrically driven MEMS mirror that reduces the device area and maintains a large driving force.

[0006] Based on the above-mentioned purpose, one or more embodiments of the present specification provide a piezoelectrically driven MEMS mirror, including: a substrate, the substrate having a relative front and back surface, the front surface having a cavity; a lens, the lens being located inside the cavity; a driving structure, the driving structure including: a first driving block, a second driving block, a third driving block and a fourth driving block, the first driving block, the second driving block, the third driving block and the fourth driving block are all fixedly connected to the inner wall of the cavity of the substrate, the first driving block is connected to the flexible rod through a first flexible connecting rod, the second driving block is connected to the flexible rod through a second flexible connecting rod, the third driving block is connected to the flexible rod through a third flexible connecting rod, the fourth driving block is connected to the flexible rod through a fourth flexible connecting rod, and the flexible rod is connected to the lens.

[0007] According to the piezoelectrically driven MEMS mirror proposed in an embodiment of the present invention, the volume of the second driving block is smaller than the first driving block and larger than the third driving block; the volume of the third driving block is larger than the fourth driving block.

[0008] According to the piezoelectrically driven MEMS mirror proposed in an embodiment of the present invention, the length of the second flexible connecting rod is greater than that of the first flexible connecting rod and smaller than that of the third flexible connecting rod; the length of the third flexible connecting rod is greater than that of the fourth flexible connecting rod.

[0009] According to the piezoelectrically driven MEMS mirror proposed in an embodiment of the present invention, the driving block close to the lens is smaller in size, thereby wrapping the central mirror. Through the principle of leverage, the device area is reduced while maintaining a larger driving force.

[0010] According to the piezoelectrically driven MEMS mirror proposed in an embodiment of the present invention, the volume of the second driving block is larger than the first driving block and smaller than the third driving block; the volume of the third driving block is smaller than the fourth driving block.

[0011] According to the piezoelectrically driven MEMS mirror proposed in an embodiment of the present invention, the length of the second flexible connecting rod is smaller than that of the first flexible connecting rod and larger than that of the third flexible connecting rod; the length of the third flexible connecting rod is smaller than that of the fourth flexible connecting rod.

[0012] The beneficial effects of the present invention are described in detail below with reference to the embodiments of the present invention and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate one or more embodiments of this specification 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 one or more embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 FIG. 1 is a top view of a piezoelectrically driven MEMS mirror according to an embodiment of the present invention.

[0015] Figure 2 Schematic diagram of the structure of the piezoelectrically driven MEMS mirror proposed in an embodiment of the present invention.

[0016] Figure 3 Schematic diagram of the structure of the piezoelectrically driven MEMS mirror proposed in an embodiment of the present invention when deflection occurs.

[0017] Figure 4 FIG. 1 is a top view of a piezoelectrically driven MEMS mirror according to another embodiment of the present invention.

[0018] Figure 5 FIG. 1 is a schematic structural diagram of a piezoelectrically driven MEMS mirror proposed in another embodiment of the present invention.

[0019] Figure 6It is a structural schematic diagram of a driving structure proposed in another embodiment of the present invention.

[0020] In the figure markings: 1. base; 2. driving structure; 2a. first driving block; 2b. second driving block; 2c. third driving block; 2d. fourth driving block; 3. flexible connecting rod; 3a. first flexible connecting rod; 3b. second flexible connecting rod; 3c. third flexible connecting rod; 3d. fourth flexible connecting rod; 4. flexible rod; 5. lens. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the present disclosure is further described in detail below with reference to specific embodiments.

[0022] The following is based on Figures 1-6 The specific structure of the piezoelectrically driven MEMS mirror in the embodiment of the present invention is described below.

[0023] Example 1

[0024] The piezoelectrically driven MEMS reflector proposed in an embodiment of the present invention includes a substrate 1 , a lens 5 , and a driving structure 2 .

[0025] The substrate 1 has opposing front and back surfaces. The front surface has a cavity. The lens 5 is located within the cavity of the substrate 1, which provides space for the lens 5 to rotate. Optionally, the piezoelectric material, upper electrode, and lower electrode on the surface of the lens 5 can be removed. Optionally, the surface of the lens 5 is provided with a metal layer, preferably an aluminum metal layer, which can increase light reflectivity.

[0026] The driving structure 2 is provided with four groups, and the four groups of driving structures 2 are arranged in a centrally symmetrical manner inside the cavity of the base 1 relative to the lens 5. The driving structure 2 includes a first driving block 2a, a second driving block 2b, a third driving block 2c and a fourth driving block 2d. The first driving block 2a, the second driving block 2b, the third driving block 2c and the fourth driving block 2d are all fixedly connected to the inner wall of the cavity of the base 1, the first driving block 2a is connected to the flexible rod 4 through the first flexible connecting rod 3a, the second driving block 2b is connected to the flexible rod 4 through the second flexible connecting rod 3b, the third driving block 2c is connected to the flexible rod 4 through the third flexible connecting rod 3c, the fourth driving block 2d is connected to the flexible rod 4 through the fourth flexible connecting rod 3d, and the flexible rod 4 is connected to the lens 5. Optionally, the widths of the first driving block 2a, the second driving block 2b, the third driving block 2c and the fourth driving block 2d are different, such as Figure 6 shown.

[0027] The length of the first flexible connecting rod 3a is smaller than that of the second flexible connecting rod 3b, the length of the second flexible connecting rod 3b is smaller than that of the third flexible connecting rod 3c, and the length of the third flexible connecting rod 3c is smaller than that of the fourth flexible connecting rod 3d; the volume of the first driving block 2a is larger than that of the second driving block 2b, the volume of the second driving block 2b is larger than that of the third driving block 2c, and the volume of the third driving block 2c is larger than that of the fourth driving block 2d. Figure 1-3 shown.

[0028] See also Figure 3 According to the piezoelectrically driven MEMS mirror proposed in an embodiment of the present invention, the volumes of the first driving block 2a, the second driving block 2b, the third driving block 2c, and the fourth driving block 2d are arranged from large to small, and the lengths of the first flexible connecting rod 3a, the second flexible connecting rod 3b, the third flexible connecting rod 3c, and the fourth flexible connecting rod 3d are arranged from small to large. In the process of driving the lens 5 to deflect, a lever is formed. Through the principle of leverage, a large driving force is maintained while reducing the device area.

[0029] The piezoelectrically driven MEMS reflector proposed in the present invention has the best performance when it is uniaxial, but is not limited to a uniaxial structure and can have biaxial or multiaxial modes and corresponding excitation methods.

[0030] Example 2

[0031] Different from Example 1, in the piezoelectrically driven MEMS mirror proposed in the embodiment of the present invention, the length of the first flexible connecting rod 3a is greater than the second flexible connecting rod 3b, the length of the second flexible connecting rod 3b is greater than the third flexible connecting rod 3c, and the length of the third flexible connecting rod 3c is greater than the fourth flexible connecting rod 3d; the volume of the first driving block 2a is smaller than the second driving block 2b, the volume of the second driving block 2b is smaller than the third driving block 2c, and the volume of the third driving block 2c is smaller than the fourth driving block 2d. Figure 4-5 shown.

[0032] The one or more embodiments of this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification shall be included within the scope of protection of this disclosure.

Claims

1. A piezoelectrically driven MEMS mirror, characterized in that: include: A substrate (1), the substrate (1) having a front side and a back side opposite to each other, the front side having a cavity; a lens (5), wherein the lens (5) is located inside the cavity; A drive structure (2), the drive structure (2) comprising: A first driving block (2a), a second driving block (2b), a third driving block (2c) and a fourth driving block (2d); the first driving block (2a), the second driving block (2b), the third driving block (2c) and the fourth driving block (2d) are all fixedly connected to the inner wall of the cavity of the substrate (1); the first driving block (2a) is connected to the flexible rod (4) via a first flexible connecting rod (3a); the second driving block (2b) is connected to the flexible rod (4) via a second flexible connecting rod (3b); the third driving block (2c) is connected to the flexible rod (4) via a third flexible connecting rod (3c); the fourth driving block (2d) is connected to the flexible rod (4) via a fourth flexible connecting rod (3d); and the flexible rod (4) is connected to the lens (5); The volume of the second driving block (2b) is smaller than that of the first driving block (2a) and larger than that of the third driving block (2c); The volume of the third driving block (2c) is larger than that of the fourth driving block (2d); The length of the second flexible connecting rod (3b) is greater than that of the first flexible connecting rod (3a) and less than that of the third flexible connecting rod (3c); The length of the third flexible connecting rod (3c) is greater than the length of the fourth flexible connecting rod (3d).

2. A piezoelectrically driven MEMS mirror, characterized in that: include: A substrate (1), the substrate (1) having a front side and a back side opposite to each other, the front side having a cavity; a lens (5), wherein the lens (5) is located inside the cavity; A drive structure (2), the drive structure (2) comprising: A first driving block (2a), a second driving block (2b), a third driving block (2c) and a fourth driving block (2d); the first driving block (2a), the second driving block (2b), the third driving block (2c) and the fourth driving block (2d) are all fixedly connected to the inner wall of the cavity of the substrate (1); the first driving block (2a) is connected to the flexible rod (4) via a first flexible connecting rod (3a); the second driving block (2b) is connected to the flexible rod (4) via a second flexible connecting rod (3b); the third driving block (2c) is connected to the flexible rod (4) via a third flexible connecting rod (3c); the fourth driving block (2d) is connected to the flexible rod (4) via a fourth flexible connecting rod (3d); and the flexible rod (4) is connected to the lens (5); The volume of the second driving block (2b) is larger than that of the first driving block (2a) and smaller than that of the third driving block (2c); The volume of the third driving block (2c) is smaller than that of the fourth driving block (2d); The length of the second flexible connecting rod (3b) is shorter than that of the first flexible connecting rod (3a) and longer than that of the third flexible connecting rod (3c); The length of the third flexible connecting rod (3c) is smaller than the length of the fourth flexible connecting rod (3d).

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