Three-point-driven MEMS universal rotating micromirror and manufacturing method thereof

Abstract

The invention discloses an MEMS universal rotating micromirror based on three-point electric field driving and a manufacturing method of the MEMS universal rotating micromirror. The micro-mirror mainly comprises a micro-lens, a three-point electric field driving system, a universal spherical hinge structure and a base. The micro-lens is connected to the base through the universal spherical hinge, and has high-precision rotation capability. The three-point electric field driving system is composed of three independent electric field driving units which are arranged at different positions below the micro-lens respectively so as to achieve multi-axis control over the micro-lens and accurate rotation in any direction. And the driving unit interacts with the micro-lens through electric field distribution force, so that universal rotation of the micro-lens is realized. The design has the advantages of simple structure, accurate control, high response speed and the like. The manufacturing method comprises a micromachining technical step to ensure the optical flatness of the micro-lens and the reliability of the driving system. The micromirror is widely applied to the fields of optical imaging, laser scanning, optical communication and the like.

Description

Technical Field

[0001] The invention relates to a MEMS universal rotating micromirror, in particular to a MEMS universal rotating micromirror based on three-point electric field drive and a manufacturing method thereof. Background Art

[0002] The rapid development of micro-electromechanical system (MEMS) technology has provided a broad space for the innovation of micro-scale devices. Among them, MEMS micromirrors, as a key optical component, have broad application prospects in the fields of optical imaging, laser scanning, optical communication, etc. Traditional micromirror designs mostly use electrostatic drive, thermal drive or magnetic drive. Although these methods have their own advantages, they have certain limitations in achieving multi-axis high-precision rotation.

[0003] Electrostatically driven micromirrors are widely used in various MEMS devices due to their low power consumption and high response speed. However, electrostatically driven micromirrors usually require a higher driving voltage, and the driving torque may be insufficient when achieving large-angle rotation. In addition, the electrostatic drive structure is complex, has high requirements for processing technology, and is easily affected by environmental conditions.

[0004] Thermally driven micromirrors achieve the rotation of micromirrors by heating materials to generate thermal expansion. The advantages of this method are simple structure and easy integration, but its response speed is relatively slow, power consumption is high, and control accuracy is limited due to the hysteresis of thermal effect. Magnetic driven micromirrors use the interaction between magnetic field and magnetic material to achieve movement, with large driving force and good linearity. However, this method usually requires an external magnetic field source, the complexity and volume of the system increase, and the uniformity and stability of the magnetic field are difficult to control. In view of the shortcomings of the above-mentioned traditional driving methods, electric field driving technology has gradually attracted attention in recent years. Electric field driving has the advantages of low power consumption, high response speed and good control accuracy, and is particularly suitable for multi-axis control and high-precision rotation of MEMS micromirrors. However, most of the electric field driven micromirrors on the market currently use single-point or two-point driving methods, which makes it difficult to achieve true universal rotation.

[0005] The present invention proposes a MEMS universal rotating micromirror based on three-point electric field drive. By arranging three independent electric field drive units under the micromirror, multi-axis control of the micromirror and precise rotation in any direction are achieved. This design not only overcomes the limitations of traditional driving methods, but also simplifies the structural design and improves the reliability and efficiency of the system. In addition, the introduction of the universal ball joint structure enables the micromirror to rotate freely in three-dimensional space, further improving the flexibility and adaptability of the system. By optimizing the micromirror material and surface treatment process, optical flatness and high reflectivity are ensured, thereby meeting the needs of high-precision optical applications. In terms of manufacturing methods, the present invention adopts advanced micromachining technology, including steps such as photolithography, chemical vapor deposition and metal sputtering, to ensure the high precision and high reliability of the micromirror and the drive system. Through a series of testing and calibration steps, the quality and consistency of each product shipped are ensured. Summary of the invention

[0006] The technical problem of MEMS universal rotating micromirror is to overcome the problems of insufficient multi-axis control precision, complex structure and slow response speed in existing micromirror systems. Traditional micromirror systems often use single or double-point drive methods, which limits the flexible operation ability of micromirrors in multi-dimensional space and makes it difficult to meet the requirements of modern optical systems for high precision and fast response. In addition, common drive methods in the prior art, such as electrostatic, thermal or magnetic drive, although each has its own advantages, have obvious limitations in terms of energy consumption, control accuracy and system complexity.

[0007] To solve the above problems, the present invention proposes a MEMS universal rotating micromirror based on three-point electric field drive. The device arranges three independent electric field drive units under the micromirror, which are spaced 120° apart from each other, to achieve multi-axis precise control of the micromirror. Each drive unit includes an electrode, an insulating layer and a corresponding control circuit. By applying different voltages, an electric field force is generated to achieve precise rotation of the micromirror in pitch, yaw and roll directions. The entire system adopts a closed-loop control strategy, combined with a position feedback sensor, to ensure the motion accuracy and stability of the micromirror.

[0008] At the same time, the micro-mirror is connected to the base through a universal ball joint structure, which provides a stable rotation fulcrum, allowing the micro-mirror to be flexibly rotated in three-dimensional space. The universal ball joint structure is made of high-strength alloy material with good elasticity and wear resistance, ensuring the stability and service life of the micro-mirror under high-frequency vibration conditions. The durability of the structure is further improved through the carefully designed shock absorption and anti-fatigue characteristics.

[0009] The MEMS universal rotating micromirror has the following advantages: high-precision multi-axis control, fast response and low power consumption, simple and durable structure, excellent optical performance, and a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Micro lens bottom view

[0011] Figure 2 Micro lens side view cross section

[0012] Figure 3 Structure diagram of three-point electric field driving device

[0013] Figure 4 Hinge Base and Pedestal Top View

[0014] Figure 5 Hinge Base and Pedestal Section

[0015] Figure 6 3D image of MEMS universal rotating micromirror driven by three points

[0016] Figure 7 Process flow chart of rotating micromirror manufacturing method

[0017] In the figure:

[0018] 1. Micro lens 2. Three-point electric field drive system 3. Universal ball joint structure

[0019] 4. Base 5. Micromirror manufacturing method 6. Silver-plated reflector

[0020] 7. Universal spherical joint 8. Metal electrode plate 9. Electric field drive unit

[0021] 10. Electrode 11. Insulation layer 12. Control circuit

[0022] 13. Voltage divider 14. Power supply 15. Position feedback sensor

[0023] 16. Hinge base A 17. Hinge base B 18. Monocrystalline silicon wafer

[0024] 19. Electrode pattern DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0026] First, the microlens (1) is a core component, which is made of a composite material and is precisely processed to ensure optical flatness. The upper surface of the microlens (1) is coated with a highly reflective silver layer (6) to improve optical performance. At the center of the lower circle of the microlens (1), a universal spherical hinge structure (3) made of aluminum alloy is set to ensure stable support during rotation. The design of the microlens (1) takes into account both lightness and high strength, and can adapt to the application requirements of fast response and high-frequency driving. The lower circumferential surface of the microlens (1) is covered with metal electrode plates (8), which realize precise control of the microlens (1) through the electric field drive system (2). The structure of the microlens (1) is as follows Figure 1 and Figure 2 shown.

[0027] The three-point electric field drive system (2) is one of the key components of the present invention. Figure 3 As shown, the system is composed of three independent electric field drive units (9), each unit including an electrode (10), an insulating layer (11) and a corresponding control circuit (12). The three electric field drive units (9) are distributed below the circular surface at the bottom of the micro lens (1) at intervals of 120° and fixed on the base (4). By applying different voltages, these units (9) can generate electric field forces with the metal electrode plate (8), thereby achieving precise control of the pitch, yaw and roll directions of the micro lens (1). The drive system (2) has a voltage divider (13) and a power supply (14) at the head end, adopts a closed-loop control strategy, and is combined with a position feedback sensor (15) to ensure the movement accuracy and stability of the micro lens (1). The system design focuses on low power consumption and high efficiency, and is suitable for long-term continuous working environment.

[0028] The universal ball joint structure (7) is the core component for realizing the multi-dimensional rotation of the micro lens (1). The structure is composed of a spherical joint (3) structure and two concave hinge bases A (16) and B (17). The spherical joint (3) structure is directly connected to the bottom surface of the micro lens (1), while the hinge bases A (16) and B (17) are connected to the base to provide the fulcrum required for the rotation of the micro lens (1). The hinge bases A (16) and B (17) are made of high-strength aluminum alloy material with smooth surface, which has good elasticity and wear resistance, ensuring the stability and reliability of the entire structure. The design also fully considers the shock absorption and anti-fatigue characteristics to increase the service life of the micro lens (1) under high-frequency vibration conditions.

[0029] In terms of the manufacturing method (5), first, the size of the lens (1) is determined, and the reflective mirror surface (6) of the micro lens (1) is formed on a single crystal silicon wafer (18) by semiconductor micromachining technology, and the surface is polished to achieve the required optical flatness. A metal electrode plate (8) is fixed below the micro lens (1), and a ball joint (7) is fixed at the center of the circle below the micro lens (1). Next, an electrode pattern (19) is made using photolithography and chemical vapor deposition technology, and metal sputtering is performed to form a driving electrode to ensure the uniformity and conductivity of the electrode, and the relevant circuit (12) is connected. Then, the universal ball joint structure (3) is assembled on the micro lens (1), specifically, half of the hinge base A (14) is fixed on the base (4), and then the ball joint (7) connected to the micro lens (1) is placed at the hinge base A (14), and then the other half of the hinge base B (15) is installed and fixed on the base (4) to ensure its rotational freedom. Finally, the control circuit (12) is connected to perform system testing and calibration, including testing the rotation accuracy of the micro-mirror (1), the response speed of the drive system (2), and overall stability, to ensure that the product meets the design requirements.

[0030] The entire manufacturing process focuses on precision control, material selection and environmental compatibility to improve product performance and service life. In addition, the manufacturing method of the device also includes a series of quality inspection and reliability verification steps to ensure the high quality and consistency of each product shipped. Specifically, it includes the inspection of the rotation accuracy of the micro-lens (1), the test of the response speed of the drive system (2), the verification of the overall stability, etc. These steps ensure the reliability and stability of the product in various application scenarios and meet the strict requirements of the high-precision optical system for the micro-lens (1) device. In actual operation, the system can accurately control the rotation angle and speed of the micro-lens (1) by adjusting the voltage of the electric field drive unit (9), thereby achieving high-precision beam control. This high-precision and high-stability rotating micro-mirror has broad application prospects in the fields of optical scanning, laser display, spectral analysis, etc.

[0031] The contents not described in detail in the present invention are well known to those skilled in the art.

Claims

1. A MEMS universal rotating micromirror mainly composed of a micromirror (1), a three-point electric field drive system (2), a universal ball joint structure (3) and a base (4), and a method for manufacturing the same. The micromirror (1) is characterized in that it is made of a composite material, the surface is precisely processed to ensure optical flatness, and it can rotate with high precision in three-dimensional space. The upper surface of the micromirror is a highly reflective silver-plated reflector (6), and at the center of the lower circle of the micromirror is an aluminum alloy universal ball joint structure (7), and the lower circumferential surface is covered with a metal electrode plate (8). The design of the micromirror takes into account lightweight and high strength to meet the application requirements of fast response and high-frequency drive, and improves the optical performance by coating a highly reflective mirror layer (6) on its surface.

2. The three-point electric field drive system (2) described in claim 1 is characterized in that: The system is composed of three independent electric field drive units (9), each of which includes an electrode (10), an insulating layer (11) and a corresponding control circuit (12). The three electric field drive units (9) are distributed below the circular surface of the micro lens (1) at an interval of 120°, and are attached to a base (4). The electric field forces are generated by applying different voltages to achieve precise rotation of the micro lens (1) in the pitch, yaw and roll directions. The drive system (2) has a voltage divider (13) and a power supply (14) at the head end, adopts a closed-loop control strategy, and is combined with a position feedback sensor (15) to ensure the movement accuracy and stability of the micro lens (1). The system is designed to have low power consumption and high efficiency, and is suitable for long-term continuous operation.

3. The universal ball joint structure (3) described in claim 1 is characterized in that: The structure is composed of a spherical hinge structure (7) and two concave hinge bases A (16) and B (17). The spherical hinge structure (7) is connected to the bottom surface of the micro lens (1). The concave hinge bases A (16) and B (17) provide a rotation fulcrum for the micro lens (1) containing the spherical hinge, so that it can rotate freely in any direction. The hinge bases A (16) and B (17) are made of high-strength aluminum alloy material with good elasticity and wear resistance to ensure the stability and reliability of the structure. In addition, the design of the hinge bases A (16) and B (17) also takes into account the shock absorption and anti-fatigue characteristics to increase the service life of the micro lens (1) under high-frequency vibration conditions.

4. The method for manufacturing a rotating micromirror as described in claim 1 (5) is characterized in that: The following steps are involved: First, a reflective mirror surface (6) of a micro lens (1) is formed on a single crystal silicon wafer (18) by micromachining technology, and the surface is polished to achieve a desired optical flatness; Secondly, the electrode pattern (19) is made by photolithography and chemical vapor deposition technology, and metal sputtering is performed to form the driving electrode (10) to ensure the uniformity and conductivity of the electrode (10); then, the universal ball joint (3) structure is assembled, and the micro lens is fixed on the base through the ball joint (7) and the two half hinge bases A (16) and B (17) to ensure its rotational freedom; finally, the system is tested and calibrated, including the rotation accuracy of the micro lens (1), the response speed of the driving system and the overall stability test to ensure that the product meets the design requirements. The entire production process focuses on precision control, material selection and environmental compatibility to improve product performance and service life. In addition, the method also includes a series of quality inspection and reliability verification steps to ensure the high quality and consistency of each product shipped.

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