This paper introduces an integrated optical auto-focus system driven by a nut-type ultrasonic motor (USM). The system comprises an optical lens as a rotor (M6 or M7), a polyhedral tube of copper as a stator; an image ...This paper introduces an integrated optical auto-focus system driven by a nut-type ultrasonic motor (USM). The system comprises an optical lens as a rotor (M6 or M7), a polyhedral tube of copper as a stator; an image sensor, and a driver IC of the motor. The sizes of the AF (auto-focus) module are 8.5 mm×8.5 mm×5.9 mm. The piezoelectric elements are bonded on the external surface of the stator. The rotor has external screw thread that engages with the inner screw thread of the stator. When the piezoelectric elements are excited by the driver IC, a bend traveling wave in plane is generated on the stator along the circle direction, that drives the lens rotor to rotate and then to move axially. The driver IC is controlled by an image feedback of an image sensor centered on the axis of the casing, then the optical focusing is realized. The power consumption is zero at rest and is less than 0.25 W in motion; focusing precision <10 μm; speed >3 r/s(180 r/min); response <10 ms; high reliability: resistant to shock and fall off; directly driven by the driver IC without transmission mechanism; the friction force is namely the driving force and noiseless. The integrated optical auto-focus system is very useful, especially for cellular phones. The image resolution of 3―5 MP has been obtained in the module prototypes of the cellular phone.展开更多
This article reports a screw-driven polyhedron linear ultrasonic motor(USM) of nut-type.It is comprised of a stator,which is a threaded metal nut bonded with piezoelectric plates on its external surface,and a rotor wi...This article reports a screw-driven polyhedron linear ultrasonic motor(USM) of nut-type.It is comprised of a stator,which is a threaded metal nut bonded with piezoelectric plates on its external surface,and a rotor with external threads,which engage with the internal threads of the stator.A traveling wave in the plane is stimulated on the stator when harmonic electric signals are applied to the piezoelectric plates.The traveling wave drives the rotor to rotate,and the threads transform the rotation into a linear motion.The lens can be fixed in the rotor and realize the integrated design of the auto focus system.This structure can omit retarder and directly drive to obtain a high accuracy of positioning,and it is shockproof.A mini AF cellular phone module(8.5 mm×8.5 mm×5.9 mm) driven by this motor was made and an image resolution of 3-5 MP was obtained in the module prototypes of the cellular phone.展开更多
The reflected field of pulsed cylindrical waves from a liquid-solid interface is studied by the numerical method and the experimental method. The reflected field is calculated and shown in gray pictures. The calculate...The reflected field of pulsed cylindrical waves from a liquid-solid interface is studied by the numerical method and the experimental method. The reflected field is calculated and shown in gray pictures. The calculated incident angles θn (n=1, 2, 3, ...) of a series of minimums (or nulls) on the reflected wavefront are presented. The measured angle of the minimum from Schlieren photograph is consistent with that by calculation. The appearance of minimums is explained by the interference between the reflected wave and the head wave, and by the radiated dissipation of the head wave. The leading phase angle of the head wave to the reflected wave is proved to be about 3π/4 by the numerical calculation.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 50577035, 10676015)High Technology Research and Development Program of China (863 Program) (Grant No. 2006AA02Z472)
文摘This paper introduces an integrated optical auto-focus system driven by a nut-type ultrasonic motor (USM). The system comprises an optical lens as a rotor (M6 or M7), a polyhedral tube of copper as a stator; an image sensor, and a driver IC of the motor. The sizes of the AF (auto-focus) module are 8.5 mm×8.5 mm×5.9 mm. The piezoelectric elements are bonded on the external surface of the stator. The rotor has external screw thread that engages with the inner screw thread of the stator. When the piezoelectric elements are excited by the driver IC, a bend traveling wave in plane is generated on the stator along the circle direction, that drives the lens rotor to rotate and then to move axially. The driver IC is controlled by an image feedback of an image sensor centered on the axis of the casing, then the optical focusing is realized. The power consumption is zero at rest and is less than 0.25 W in motion; focusing precision <10 μm; speed >3 r/s(180 r/min); response <10 ms; high reliability: resistant to shock and fall off; directly driven by the driver IC without transmission mechanism; the friction force is namely the driving force and noiseless. The integrated optical auto-focus system is very useful, especially for cellular phones. The image resolution of 3―5 MP has been obtained in the module prototypes of the cellular phone.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 50577035 & 10676015)National High-Tech Research and Development Program of China (Grant No. AA02Z472)
文摘This article reports a screw-driven polyhedron linear ultrasonic motor(USM) of nut-type.It is comprised of a stator,which is a threaded metal nut bonded with piezoelectric plates on its external surface,and a rotor with external threads,which engage with the internal threads of the stator.A traveling wave in the plane is stimulated on the stator when harmonic electric signals are applied to the piezoelectric plates.The traveling wave drives the rotor to rotate,and the threads transform the rotation into a linear motion.The lens can be fixed in the rotor and realize the integrated design of the auto focus system.This structure can omit retarder and directly drive to obtain a high accuracy of positioning,and it is shockproof.A mini AF cellular phone module(8.5 mm×8.5 mm×5.9 mm) driven by this motor was made and an image resolution of 3-5 MP was obtained in the module prototypes of the cellular phone.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 19604008 and 10074039).
文摘The reflected field of pulsed cylindrical waves from a liquid-solid interface is studied by the numerical method and the experimental method. The reflected field is calculated and shown in gray pictures. The calculated incident angles θn (n=1, 2, 3, ...) of a series of minimums (or nulls) on the reflected wavefront are presented. The measured angle of the minimum from Schlieren photograph is consistent with that by calculation. The appearance of minimums is explained by the interference between the reflected wave and the head wave, and by the radiated dissipation of the head wave. The leading phase angle of the head wave to the reflected wave is proved to be about 3π/4 by the numerical calculation.
