High efficiency voice coil loudspeaker voice coil driver and deformable mirror
阅读说明：本技术 一种高效率音圈驱动器及变形镜 (High efficiency voice coil loudspeaker voice coil driver and deformable mirror ) 是由 胡立发 曹硕 张志高 赵子云 顾虎 于 2020-07-30 设计创作，主要内容包括：本发明公开了一种高效率音圈驱动器及变形镜,属于自适应光学领域。本发明通过推导音圈驱动器电机常数的解析公式,掌握了影响音圈驱动器效率的因素,设计了一种新的结构的音圈驱动器；在此基础上,利用有限元的方法进行仿真,对永磁体、线圈的几何参数、物理参数进行了优化,并用电机常数进行评价,得出最佳的参数数据：包括永磁体内径、外径和厚度,线圈的内径、外径和厚度,以及永磁体和线圈之间的气隙大小。在不改变音圈的匝数条件下,就达到了提高音圈驱动器效率150％的优异效果,更适用于制作大驱动单元数、低损耗和高调制精度的音圈变形镜。(The invention discloses a high-efficiency voice coil driver and a deformable mirror, and belongs to the field of adaptive optics. The invention grasps the factors influencing the efficiency of the voice coil driver by deducing the analytic formula of the motor constant of the voice coil driver, and designs the voice coil driver with a new structure; on the basis, a finite element method is used for simulation, geometric parameters and physical parameters of the permanent magnet and the coil are optimized, and a motor constant is used for evaluation to obtain the optimal parameter data: including the permanent magnet inner diameter, outer diameter and thickness, the coil inner diameter, outer diameter and thickness, and the air gap size between the permanent magnet and the coil. Under the condition of not changing the number of turns of the voice coil, the excellent effect of improving the efficiency of the voice coil driver by 150% is achieved, and the method is more suitable for manufacturing the voice coil deformable mirror with large driving unit number, low loss and high modulation precision.)
1. A voice coil driver comprises a thin mirror surface, an annular permanent magnet and coils coaxial with the permanent magnet, and is characterized in that the voice coil driver is provided with two coils, and soft magnetic materials are not arranged in the two coils;
the annular permanent magnet is arranged between the two coils and is connected with the thin mirror surface through a rod;
for convenience of description, the two coils are respectively called coil one and coil two; the thin mirror surface, the first coil, the annular permanent magnet and the second coil are sequentially arranged, and an air gap exists between the two adjacent thin mirror surfaces.
2. The voice coil driver of claim 1, wherein the annular permanent magnet is fabricated from neodymium-iron-boron material and the rod is fabricated from a material that is neither magnetically nor thermally conductive.
3. The voice coil driver of claim 1, wherein the magnetization direction of the annular permanent magnet is radial magnetization.
4. The voice coil driver as claimed in claim 1, wherein the air gap between the annular permanent magnet and the coil is 0.01-0.5 mm thick.
5. The voice coil driver as claimed in claim 1, wherein the annular permanent magnet has a thickness of 1 to 5 mm.
6. The voice coil driver as claimed in claim 1, wherein the annular permanent magnet has an outer diameter of 3 to 7mm and an inner diameter of 0.3 to 0.7 mm.
7. The voice coil driver of claim 1, wherein the coil height is 4-8 mm.
8. The voice coil driver as claimed in claim 1, wherein the coil has an outer radius of 3 to 7mm and an inner radius of 0.3 to 0.7 mm.
9. The voice coil driver of claim 1, wherein the air gap between the annular permanent magnet and the coil is 0.1mm thick, the annular permanent magnet is 3mm thick, the annular permanent magnet has an outer diameter of 5mm and an inner diameter of 0.5mm, the coil height is 6mm, the coil outer radius is 5mm, and the coil inner radius is 0.5 mm.
10. A deformable mirror for driving thin mirror deformation using a voice coil actuator as claimed in any one of claims 1 to 9.
Technical Field
The invention relates to a high-efficiency voice coil driver and a deformable mirror, and belongs to the field of adaptive optics.
Background
Babcock in 1953 first proposed the concept of adaptive optics, i.e. to increase the resolution of the target image by detecting and correcting in real time the optical distortions caused by atmospheric turbulence. The deformable mirror is one of the core devices of the adaptive optics system. Through years of research and development, people develop different types of deformable mirrors: PZT deformable mirror, electrostrictive deformable mirror, film deformable mirror, MEMS, voice coil deformable mirror, etc., and can be widely applied to the fields of astronomical observation, microscopic imaging, high-power laser, fundus imaging, etc. The PZT deformable mirror is the most widely used deformable mirror at present, but has magnetic hysteresis and low modulation amount, so that the application of the PZT deformable mirror in the aspect of a secondary mirror of a large-caliber telescope is limited. Compared with a PZT deformable mirror, the voice coil deformable mirror has the advantages of large modulation amount, no magnetic hysteresis, simple structure, small volume, low noise, high specific thrust, high response speed, high precision, convenience in maintenance, high reliability and the like.
Salinari, p.s. of the achilles astronomical stage in italy, 1993, proposed a voice coil driver-based noncontact deformable mirror, and developed 30-unit and 36-unit voice coil deformable mirrors in 1999, with error attenuation of up to 100 hz (0 db attenuation level), whose voice coil driver basic structure is a cylindrical permanent magnet bonded under a thin mirror surface, and a coil spaced about 100 μm below the permanent magnet, which is also called a noncontact voice coil deformable mirror, as shown in fig. 1. In 2002, the 336-unit voice coil deformable mirror of the MMT is successfully developed and used as a secondary mirror of the MMT telescope, so that a self-adaptive optical system is greatly simplified, and the utilization efficiency of incident light is improved. The specific Stokes 'ratio in the H band reaches 0.2, the specific Stokes' ratio in the M band reaches 0.98 [ Wildi F P, Brussa G, Lloyd-Hart M, et al first light of the 6.5-M MMT Adaptive Optics system [ C ], analog Adaptive Optics Systems and applications, Editdby type, Robert K.; Lloyd-Hart, Michael. International Society for Optics and Photonics,2003 ]. In 2010, a voice coil distorting mirror with 672 drivers was mounted on the LBT telescope, with a Stokes ratio in the H band of 0.8 [ [ Xompero Marcoa, Armando Ricccardia, Daniela Zanatota.Adaptive second mirror for LBT and its capacitive sensors? [C] SPIE Proc,2008.7015(3Q):1-9 ]. The deformed secondary mirror of the VLT telescope, which was formally operated in 2012, has 1170 voice coil drivers, and the fitting error rms of all modes is 62.5nm [ Arsenault R, Biasi R, galieni D, et al.a. formable second approximation mirror for the VLT [ C ] advanced Optics ii.2006 ], unlike the former, whose permanent magnet is not directly bonded to the mirror surface, but is arranged in the middle of two lines and is connected to the mirror surface by a rod, as shown in fig. 2. Research on voice coil deformable mirrors has also been conducted by several groups in China. A moving magnet type voice coil motor is designed by institute of photoelectric technology in Chinese academy of sciences, the output force can reach +/-0.5N, the step response time is 50ms, the fitting PV value of defocusing aberration can reach 50um [ Zhang Yufang, Lizhongping ], the voice coil force actuator for thin mirror active optics is designed [ J ], the optical precision engineering, 2013,21(11):2836 and 2844 ]. The Changchun optical machine corrects the surface shape of a 400mm reflector through a voice coil driver, and the corrected RMS can reach lambda/40 [ Wangtong.
The basic principle of the voice coil distorting mirror is that the voice coil driver drives the thin mirror surface to distort by generating electromagnetic force, therefore, in the design of the voice coil distorting mirror, the motor constant K is a key parameter which is used for measuring the efficiency of the voice coil driver and expresses the magnitude of effective thrust generated by unit power loss, the larger the value of K is, the higher the efficiency of the driver is, and the formula is as follows:
where F is the output force of the voice coil driver and P is the power consumption of the voice coil driver. Under the same deformation quantity, the voice coil driver with low efficiency can generate excessive heat, the heat accumulation causes temperature rise, and in severe cases, local deformation of the thin mirror surface is caused, and finally, the compensation precision and the working stability of the deformable mirror are reduced. For the two types of drivers shown in fig. 1 and 2, the efficiency of the non-contact voice coil driver shown in fig. 1 is relatively low, the motor constant K reported at home and abroad is generally not more than 0.7, the driver has a simple structure, and the generated force is relatively small; the contact type voice coil driver shown in fig. 2 has relatively high efficiency, a soft iron component is usually required to be added in the coil, the motor constant K can reach about 5, but the overall structure is complex, and the volume is large. In order to meet the application requirements, people are urgently required to develop a voice coil driver with simple structure and high efficiency.
Disclosure of Invention
In order to improve the efficiency of the voice coil driver of the deformable mirror and simultaneously avoid the problems of complex structure and large volume, the invention provides a high-efficiency voice coil driver for the deformable mirror with a novel structure. This voice coil loudspeaker voice coil driver's mechanism is different from current voice coil loudspeaker voice coil driver, and this application designs out efficient voice coil loudspeaker voice coil driver for novel deformable mirror through optimizing its structural parameter and material.
A voice coil driver comprises a thin mirror surface, an annular permanent magnet and coils coaxial with the permanent magnet, wherein the voice coil driver is provided with two coils, and soft magnetic materials are not arranged in the two coils; the annular permanent magnet is arranged between the two coils and is connected with the thin mirror surface through a rod;
for convenience of description, the two coils are respectively called coil one and coil two; the thin mirror surface, the first coil, the annular permanent magnet and the second coil are sequentially arranged, and an air gap exists between the two adjacent thin mirror surfaces.
Optionally, the annular permanent magnet is made of neodymium iron boron materials, and the rod is made of materials which are not magnetic conductive and not heat conductive.
Optionally, the material that is not magnetically or thermally conductive includes epoxy.
Optionally, the magnetizing direction of the annular permanent magnet is radial magnetizing.
Optionally, the thickness of the air gap between the annular permanent magnet and the coil is 0.01-0.5 mm.
Optionally, the thickness of the annular permanent magnet is 1-5 mm.
Optionally, the outer diameter of the annular permanent magnet is 3-7 mm, and the inner diameter is 0.3-0.7 mm.
Optionally, the height of the coil is 4-8 mm.
Optionally, the outer radius of the coil is 3-7 mm, and the inner radius of the coil is 0.3-0.7 mm.
Optionally, air gap thickness between annular permanent magnet and the coil is 0.1mm, annular permanent magnet's thickness is 3mm, annular permanent magnet's external diameter is 5mm, the internal diameter is 0.5mm, the coil height is 6mm, the coil external radius is 5mm, the coil internal radius is 0.5 mm.
The application also provides a deformable mirror, which is characterized in that the deformable mirror adopts the voice coil driver to drive the thin mirror surface to deform.
The application also provides an application method of the deformable mirror in the field of adaptive optics, and the deformable mirror adopts the voice coil driver to drive the thin mirror surface to deform.
The invention has the beneficial effects that:
the voice coil driver provided by the application does not introduce a soft magnetic component into the coil, so that the complexity and the volume of the system are reduced, meanwhile, compared with a non-contact voice coil driver, the voice coil driver provided by the application is additionally provided with the coil, the force is increased, the direction of the force is provided, the efficiency of the voice coil driver is improved, and the motor constant is improved by at least 150% compared with that of the traditional voice coil driver. Therefore, the voice coil driver with the new structure has higher efficiency and more compact structure, and meets the requirements of practical application better.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic diagram of a single driver of a non-contact voice coil deformable mirror; wherein 1 is a thin mirror surface, 2 is an annular permanent magnet, and 3 is a coil coaxial with the
FIG. 2 is a schematic diagram of a single driver for a contact voice coil deformer; wherein 1 is a thin mirror surface, 2 is an annular permanent magnet, 3 is a coil coaxial with the permanent magnet, and 4 is a soft iron material part; an annular
FIG. 3 is a schematic diagram of a single driver of a voice coil deformable mirror according to the present invention; wherein 1 is a thin mirror surface, 2 is an annular permanent magnet, 3 is a coil coaxial with the permanent magnet, and 5 is a cylindrical rod made of epoxy resin material, and the
FIG. 4 is a schematic diagram of the lower half of a single driver of a voice coil distorting mirror according to the present invention; 2, an annular permanent magnet is made of neodymium iron boron; and 3, a coil coaxial with the permanent magnet is made of copper. The main parameters are as follows: the inner radius and the outer radius of the permanent magnet are Rm and Rm respectively, and the thickness of the permanent magnet is hm; the inner radius and the outer radius of the coil are Rc and Rc respectively, and the thickness of the coil is hc; the thickness of the air gap between the permanent magnet and the coil is dg;
FIG. 5 is a simulation diagram of the relationship between the electromagnetic force and different magnetizing directions of the magnet; the circle corresponds to radial magnetization, the triangle corresponds to axial magnetization, and the longitudinal axis is electromagnetic force;
FIG. 6 is a simulation diagram of the variation of electromagnetic force and motor constant K under different air gap sizes; the solid line corresponds to the electromagnetic force of the left vertical axis and the dashed line corresponds to the motor constant K of the right vertical axis.
FIG. 7 is a simulation diagram of the variation of electromagnetic force and motor constant K under different magnet thicknesses; the solid line corresponds to the electromagnetic force of the left vertical axis and the dashed line corresponds to the motor constant K of the right vertical axis.
FIG. 8 is a simulation diagram of the variation of electromagnetic force and motor constant K under different magnet outer diameters; the solid line corresponds to the electromagnetic force of the left vertical axis and the dashed line corresponds to the motor constant K of the right vertical axis.
FIG. 9 is a simulation diagram of the variation of electromagnetic force and motor constant K under different magnet inner diameters; the solid line corresponds to the electromagnetic force of the left vertical axis and the dashed line corresponds to the motor constant K of the right vertical axis.
FIG. 10 is a simulation diagram of the variation of electromagnetic force and motor constant K under different coil heights; the solid line corresponds to the electromagnetic force of the left vertical axis and the dashed line corresponds to the motor constant K of the right vertical axis.
FIG. 11 is a simulation diagram of the variation of electromagnetic force and motor constant K under different coil outer diameters; the solid line corresponds to the electromagnetic force of the left vertical axis and the dashed line corresponds to the motor constant K of the right vertical axis.
FIG. 12 is a simulation diagram of the variation of electromagnetic force and motor constant K under different coil inner diameters; the solid line corresponds to the electromagnetic force of the left vertical axis and the dashed line corresponds to the motor constant K of the right vertical axis.
Fig. 13 is a graph showing driving force and efficiency comparison simulation of the voice coil driver (indicated by five-pointed star) according to the present invention and the conventional contactless voice coil driver (indicated by an asterisk) at different input currents; the electromagnetic force and the motor constant K are changed along with the input current, the solid line corresponds to the electromagnetic force of the left vertical axis, and the dotted line corresponds to the motor constant K of the right vertical axis.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
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