An electrothermal torsional actuator with a stripe structure

Abstract

An electrothermal torsion actuator 1 with a stripe structure, one end of which is connected to a fixed end 2, and the other end is connected to a movable unit 3. The electrothermal torsion actuator 1 with a stripe structure is composed of at least two films made of materials with different thermal expansion coefficients, namely an upper film 1-1 and a lower film 1-2, wherein the upper film 1-1 includes two or more strip-like structures, which are arranged on the lower film 1-2 at intervals, and the strip-like structures and the lower film 1-2 below them form a torsion unit 4, and the center line 4-1 of each torsion unit 4 can be a straight line or a curve and form an inclination angle with the end face of the fixed end 2. When the temperature of the electrothermal torsion actuator 1 with a stripe structure changes, the electrothermal torsion actuator 1 with a stripe structure produces torsion, thereby driving the movable unit 3 to rotate. Advantages: It solves the technical problem that the existing electrothermal MEMS actuator is not easy to torsion, and has the characteristics of simple structure and easy implementation.

Description

Technical Field

[0001] The invention relates to an electrothermal torsion actuator with a stripe structure, belonging to the technical field of MEMS application. Background Art

[0002] MEMS drive methods are mainly divided into four types: electrostatic, electromagnetic, electrothermal and piezoelectric. Among them, electrostatic and electromagnetic are commonly used in torsional drive methods. Electrothermal is usually applied to vertical displacement and is difficult to apply to torsional drive. Even if it is applied to torsional drive, its structure is very complicated. For example, Patent Document 1, A Micro-Electromechanical System Torsion Mirror Driver, Manufacturing Method and Application (200410053563.3), discloses an implementation scheme of electrostatic drive for torsional state. Summary of the invention

[0003] The technical problem to be solved by the present invention is how to twist the electrothermal MEMS driver.

[0004] The technical solution adopted by the invention is: an electrothermal torsion actuator 1 with a stripe structure, one end of the electrothermal torsion actuator 1 with a stripe structure is connected to a fixed end 2, and the other end is connected to a movable unit 3, the electrothermal torsion actuator 1 with a stripe structure is composed of at least two films composed of materials with different thermal expansion coefficients, namely an upper film 1-1 and a lower film 1-2, wherein the upper film 1-1 comprises two or more strip structures, the strip structures are arranged on the lower film 1-2 at intervals, the strip structures and the lower film 1-2 below them form a torsion unit 4, the center line 4-1 of each torsion unit 4 can be a straight line or a curve, the center line 4-1 forms an inclination angle with the end face of the fixed end 2, when the temperature of the electrothermal torsion actuator 1 with a stripe structure changes, the electrothermal torsion actuator 1 with a stripe structure produces torsion, thereby driving the movable unit 3 to rotate.

[0005] The inclination angle between the center line 4 - 1 of the torsion unit and the fixed end 2 is 45°.

[0006] The lower film 1-2 is a continuous film.

[0007] The material of the upper film 1 - 1 is a dielectric, such as an oxide or a polymer, and the material of the lower film 1 - 2 is a metal.

[0008] The upper film 1-1 is made of metal copper, and the lower film 1-2 is made of metal tungsten.

[0009] The electrothermal torsion actuators 1 of the stripe structure are installed on both sides of the movable unit 3, which are the first electrothermal torsion actuator 1A of the stripe structure and the second electrothermal torsion actuator 1B of the stripe structure. The first electrothermal torsion actuator 1A of the stripe structure and the second electrothermal torsion actuator 1B of the stripe structure are connected to the movable unit 3 by flexible structures 5. The flexible structure 5 can be a spring.

[0010] A stripe-shaped electrothermal torsion drive group 6 is provided. The stripe-shaped electrothermal torsion drive group 6 is composed of two stripe-shaped electrothermal torsion drives 1 butted against each other at the sides.

[0011] The stripe-shaped electrothermal torsion actuator group 6 is symmetrically installed on both sides of the movable unit 3 , and the stripe-shaped electrothermal torsion actuator group 6 is connected to the movable unit 3 using a flexible structure 5 .

[0012] The advantages of the invention are as follows: the technical problem that the existing electrothermal MEMS driver is difficult to twist is solved, and the invention has the characteristics of simple structure and easy implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of an electrothermal torsional actuator 1 with a stripe structure in Example 1.

[0014] Figure 2 It is a schematic diagram of an electrothermal torsional actuator 1 with a stripe structure in Example 2.

[0015] Figure 3 It is a schematic diagram of the two electrothermal torsion actuators driving the mirrors of the stripe-shaped structures described in Example 3.

[0016] Figure 4 This is a microscopic photograph of Example 3 in the laboratory.

[0017] Figure 5 It is a schematic diagram of an electrothermal torsional actuator group 6 with a stripe structure in Example 4.

[0018] Figure 6 It is a schematic diagram of the two stripe-shaped electrothermal torsion actuator groups 6 driving the mirror described in Example 5.

[0019] Figure 7 It is a schematic diagram of the ribbon structure in the shape of noodles.

[0020] In the figure, 1 is an electrothermal torsion actuator with a stripe structure, 1-1 is an upper film, 1-2 is a lower film, 2 is a fixed end, 3 is a movable unit, 4 is a torsion unit, 4-1 is the center line of the torsion unit, 5 is a flexible structure, and 6 is an electrothermal torsion actuator group with a stripe structure. DETAILED DESCRIPTION

[0021] An electrothermal torsion actuator 1 with a stripe structure, one end of which is connected to a fixed end 2, and the other end is connected to a movable unit 3. The electrothermal torsion actuator 1 with a stripe structure is composed of at least two films made of materials with different thermal expansion coefficients, namely an upper film 1-1 and a lower film 1-2, wherein the upper film 1-1 comprises two or more strip-like structures, the strip-like structures are arranged on the lower film 1-2 at intervals, and the strip-like structures and the lower film 1-2 below them form a torsion unit 4. The center line 4-1 of each torsion unit 4 can be a straight line or a curve, and the center line 4-1 forms an inclination angle with the end face of the fixed end 2. When the temperature of the electrothermal torsion actuator 1 with a stripe structure changes, the electrothermal torsion actuator 1 with a stripe structure produces torsion, thereby driving the movable unit 3 to rotate.

[0022] The inclination angle between the center line 4 - 1 of the torsion unit and the fixed end 2 is 45°.

[0023] The lower film 1-2 is a continuous film.

[0024] The material of the upper film 1 - 1 is a dielectric, such as an oxide or a polymer, and the material of the lower film 1 - 2 is a metal.

[0025] The upper film 1-1 is made of metal copper, and the lower film 1-2 is made of metal tungsten.

[0026] The electrothermal torsion actuators 1 of the stripe structure are installed on both sides of the movable unit 3, which are the first electrothermal torsion actuator 1A of the stripe structure and the second electrothermal torsion actuator 1B of the stripe structure. The first electrothermal torsion actuator 1A of the stripe structure and the second electrothermal torsion actuator 1B of the stripe structure are connected to the movable unit 3 by flexible structures 5. The flexible structure 5 can be a spring.

[0027] A stripe-shaped electrothermal torsion drive group 6 is provided. The stripe-shaped electrothermal torsion drive group 6 is composed of two stripe-shaped electrothermal torsion drives 1 butted against each other at the sides.

[0028] The stripe-shaped electrothermal torsion actuator group 6 is symmetrically installed on both sides of the movable unit 3 , and the stripe-shaped electrothermal torsion actuator group 6 is connected to the movable unit 3 using a flexible structure 5 .

[0029] Example 1

[0030] like Figure 1As shown, the electrothermal torsion actuator 1 of the stripe-shaped structure is composed of two layers of films, namely an upper film 1-1 and a lower film 1-2. The upper film 1-1 is composed of a plurality of strip-shaped structures, which are arranged on the lower film 1-2 at intervals. The strip-shaped structures are strip-shaped, and the specific shapes include but are not limited to parallelograms, polygons, noodles (such as Figure 7 As shown) or other irregular shapes, the strip-like structure and the lower film 1-2 below it form a torsion unit 4, the center line 4-1 of each torsion unit 4 can be a straight line or a curve, and the center line 4-1 forms an inclined angle with the end face of the fixed end 2. When the temperature of the electrothermal torsion actuator 1 of the stripe-like structure changes, the electrothermal torsion actuator of the stripe-like structure bends toward the film layer with a smaller thermal expansion coefficient. Since the force generated by the torsion unit 4 forms a certain angle with the fixed end 2, part of the force generates bending in the Z-axis direction, and the other part of the force causes the electrothermal torsion actuator of the stripe-like structure to rotate around the X-axis direction, thereby driving the movable unit 3 to rotate. The upper film 1-1 and the lower film 1-2 are interchanged in position, which should also be considered within the scope of protection of this application.

[0031] Example 2

[0032] This embodiment shows an electrothermal torsion actuator with a stripe structure composed of a Cu-W double-layer structure. The difference between this embodiment and embodiment 1 is that except for the torsion unit 4 close to the fixed end, the other torsion units 4 are not connected to the fixed end 2.

[0033] like Figure 2 As shown, the overall electrothermal torsion actuator is rectangular, the material of the upper film 1-1 is metal copper, and the material of the lower film 1-2 is metal tungsten. The center line 4-1 of the torsion unit 4 is at a 45-degree angle with the boundary of the electrothermal torsion actuator 1 of the stripe structure. When the temperature rises, the electrothermal torsion actuator 1 of the stripe structure bends toward the metal tungsten layer with a smaller thermal expansion coefficient. Since the center line 4-1 of the torsion unit 4 is at a 45-degree angle with the boundary, a part of the thermal stress of the torsion unit 4 bends in the vertical direction, and the other part of the force causes the electrothermal torsion actuator 1 of the stripe structure to rotate around the X-axis direction.

[0034] Example 3

[0035] This embodiment shows an example of using two electrothermal twisting actuators 1 with stripe structures to drive a mirror. The mirror is a movable unit 3 .

[0036] like Figure 3 , Figure 4As shown, the electrothermal torsion actuators 1 of the stripe-shaped structure are symmetrically installed on both sides of the movable unit 3, which are the electrothermal torsion actuators 1A of the first stripe-shaped structure and the electrothermal torsion actuators 1B of the second stripe-shaped structure. The electrothermal torsion actuators 1A of the first stripe-shaped structure and the electrothermal torsion actuators 1B of the second stripe-shaped structure are connected to the movable unit 3 by flexible structures 5, respectively. The flexible structures 5 are springs.

[0037] When the electrothermal twisting actuator with a stripe structure is heated, the mirror surface will rotate along the X axis along with the electrothermal twisting actuator with a stripe structure. When the temperature of the electrothermal twisting actuator with a stripe structure 1 rises, the mirror surface twists.

[0038] Example 4

[0039] Embodiment 3 uses a single electrothermal torsion actuator with a stripe structure to drive the movable unit 3. Since the electrothermal torsion actuator with a stripe structure will be twisted when heated, it will also rise to the side with a lower thermal expansion coefficient, which is difficult to control.

[0040] To this end, the present embodiment uses a stripe-shaped electrothermal torsion actuator group 6 (eg, Figure 5 As shown in FIG. 1 ), the stripe-shaped electrothermal torsion actuator group 6 is composed of two stripe-shaped electrothermal torsion actuators 1 arranged side by side and butted against each other on the sides, namely, the third stripe-shaped electrothermal torsion actuator 1C and the fourth stripe-shaped electrothermal torsion actuator 1D. When the stripe-shaped electrothermal torsion actuator group 6 is twisted, the third stripe-shaped electrothermal torsion actuator 1C and the fourth stripe-shaped electrothermal torsion actuator 1D have the same twisting direction but opposite lifting directions, and the movable unit 3 will twist around the central axis of the third stripe-shaped electrothermal torsion actuator 1C and the fourth stripe-shaped electrothermal torsion actuator 1D.

[0041] Example 5

[0042] This embodiment shows an example of using two stripe-shaped electrothermal twist actuator groups 6 to drive the mirror.

[0043] like Figure 6As shown, the electrothermal torsion drive groups 6 with stripe structures are symmetrically installed on both sides of the movable unit 3, which are the first electrothermal torsion drive group 6A with stripe structures and the second electrothermal torsion drive group 6B with stripe structures. The first electrothermal torsion drive group 6A with stripe structures and the second electrothermal torsion drive group 6B with stripe structures are connected to the movable unit 3 with flexible structures 5. When the temperature changes, the electrothermal torsion drive groups 6 with stripe structures on both sides of the mirror surface twist to one side at the same time, driving the mirror surface to rotate accordingly. The finite element simulation results of the structure show that the mirror surface rotates around the Y-axis direction with the electrothermal torsion drive group 6 with stripe structures.

Claims

1. An electrothermal torsion actuator (1) having a stripe structure, characterized in that: One end of the stripe-shaped electrothermal torsion actuator (1) is connected to a fixed end (2), and the other end is connected to a movable unit (3). The stripe-shaped electrothermal torsion actuator (1) is composed of at least two films made of materials with different thermal expansion coefficients, namely an upper film (1-1) and a lower film (1-2). The upper film (1-1) comprises more than two strip-shaped structures, and the strip-shaped structures are arranged on the lower film (1-2) at intervals. The strip-shaped structures and the lower film (1-2) below them form a torsion unit (4). The center line (4-1) of each torsion unit (4) is a curve, and the center line (4-1) forms an inclination angle with the end face of the fixed end (2). When the temperature of the stripe-shaped electrothermal torsion actuator (1) changes, the stripe-shaped electrothermal torsion actuator (1) generates torsion, thereby driving the movable unit (3) to rotate. The material of the upper film (1-1) is a dielectric, and the material of the lower film (1-2) is a metal.

2. The electrothermal torsion actuator (1) with a stripe structure according to claim 1, characterized in that: The inclination angle between the center line (4-1) of the torsion unit and the fixed end (2) is 45°.

3. The electrothermal torsion actuator (1) with a stripe structure according to claim 1, characterized in that: The lower film (1-2) is a continuous film.

4. The electrothermal torsion actuator (1) with a stripe structure according to claim 1, characterized in that: The material of the upper film (1-1) is metal copper, and the material of the lower film (1-2) is metal tungsten.

5. The electrothermal torsion actuator (1) with a stripe structure according to claim 1, characterized in that: The electrothermal torsion actuators (1) with stripe-shaped structures are installed on both sides of the movable unit (3), which are respectively the electrothermal torsion actuators (1A) with a first stripe-shaped structure and the electrothermal torsion actuators (1B) with a second stripe-shaped structure. The electrothermal torsion actuators (1A) with a first stripe-shaped structure and the electrothermal torsion actuators (1B) with a second stripe-shaped structure are respectively connected to the movable unit (3) using flexible structures (5).

6. An electrothermal torsion actuator assembly (6) having a stripe structure, characterized in that: The invention comprises two electrothermal torsion actuators (1) as claimed in claim 1, wherein the electrothermal torsion actuator group (6) of the stripe-shaped structure is composed of two electrothermal torsion actuators (1) of the stripe-shaped structure butted against each other at the sides; the electrothermal torsion actuator group (6) of the stripe-shaped structure is symmetrically mounted on both sides of the movable unit (3), and the electrothermal torsion actuator group (6) of the stripe-shaped structure is connected to the movable unit (3) by a flexible structure (5).

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