Showing papers by "Jinchun Hu published in 2014"

System Parameter Identification: Information Criteria and Algorithms

Abstract: Recently, criterion functions based on information theoretic measures (entropy, mutual information, information divergence) have attracted attention and become an emerging area of study in signal processing and system identification domain. This book presents a systematic framework for system identification and information processing, investigating system identification from an information theory point of view. The book is divided into six chapters, which cover the information needed to understand the theory and application of system parameter identification. The authors' research provides a base for the book, but it incorporates the results from the latest international research publications. One of the first books to present system parameter identification with information theoretic criteria so readers can track the latest developmentsContains numerous illustrative examples to help the reader grasp basic methods

Planar motor-driven coarse motion and fine motion integrated mask platform

Abstract: The invention discloses a planar motor-driven coarse motion and fine motion integrated mask platform. The coarse motion and fine motion integrated mask platform comprises a coarse motion and fine motion integrated mask platform moving platform, a balance mass, a drive motor, a mask plate, a base, a vibration isolation system and a measurement system, wherein the vibration isolation system is positioned between the balance mass and the base; the mask plate is arranged on the coarse motion and fine motion integrated mask platform moving platform; the drive motor of the mask platform moving platform is a moving iron planar motor; the rotor of the planar motor is a permanent magnet array arranged at the top surface of the coarse motion and fine motion integrated mask platform moving platform; the stator of the planar motor is a coil array arranged on the balance mass. According to the planar motor-driven coarse motion and fine motion integrated mask platform, the design complexity of the drive motor of the mask platform moving platform can be reduced; compared with a linear motor, the planar motor can provide push force in more directions and can reduce the number of the motors, so that the structure of the coarse motion and fine motion integrated mask platform moving platform is more compact, and the natural frequency and the control bandwidth of the coarse motion and fine motion integrated mask platform moving platform are improved; therefore, the control precision is improved.

Planar motor driven magnetic suspension coarse/micro motion integrated reticle stage

Abstract: The invention discloses a planar motor driven magnetic suspension coarse/micro motion integrated reticle stage. The coarse/micro motion integrated reticle stage comprises a coarse/micro motion integrated reticle stage moving table, a balance mass, a driving motor, a mask plate, a base, a vibration isolation system and a measurement system, wherein the vibration isolation system is positioned between the balance mass and the base; the mask plate is arranged on the coarse/micro motion integrated reticle stage moving table; a driving motor of the reticle stage moving table is a moving iron type planar motor; a rotor of the planar motor is a permanent magnet array arranged on the top surface of the coarse/micro motion integrated reticle stage moving table; a stator of the planar motor is a coil array arranged on the balance mass. The design complexity of the driving motor of the reticle stage moving table can be lowered; compared with a linear motor, the planar motor can provide thrust in multiple directions, and the number of motors is reduced, so that the coarse/micro motion integrated reticle stage moving table is compact in structure, the inherent frequency and the control bandwidth of the coarse/micro motion integrated reticle stage movable table are improved, and the control precision is further improved.

Two-dof heterodyne grating interferometer displacement measurement system

Abstract: A two-DOF heterodyne grating interferometer displacement measurement system, comprising a dual-frequency laser, a grating interferometer, a measurement grating, receivers and an electronic signal processing component, wherein the grating interferometer comprises a polarizing spectroscope, a reference grating and dioptric elements. The measurement system achieves the displacement measurement on the basis of the grating diffraction, the optical Doppler effect and the optical beat frequency principle. When the grating interferometer and the measurement grating conduct two-DOF linear relative motion, the system can output two linear displacements. The measurement system can achieve sub-nanometer or even higher resolution and accuracy, and can simultaneously measure two linear displacements. The measurement system has the advantages of insensitivity to the environment, high measurement accuracy, a small volume and light weight, and can improve the comprehensive performance of a workpiece stage as a position measurement system for an ultra-precise workpiece stage of a photoetching machine.

Optical grating phase modulator for laser interference photoetching system

Abstract: An optical grating phase modulator (1, 2) for a laser interference photoetching system is composed of a substrate (11, 21), an optical grating (12, 22), an electric motor (13, 23) and an optical grating positioner (4). The optical grating (12, 22), the electric motor (13, 23) and the optical grating positioner (4) are all mounted on the substrate (11, 21). The optical grating (12, 22) is circular or rectangular, and adopt transmission or reflection type optical grating. A light beam is incident on the optical grating (12, 22) and generates diffraction, and when the electric motor (13, 23) drives the optical grating (12, 22) to continuously move relative to the incident light beam, diffracted light will generate a frequency shift, thereby realizing the phase modulation of the light beam. Compared to an electro-optic phase modulator and the phase modulation mode of a micromotor driving a reflector base applied in an interference photoetching system, this optical grating phase modulator has the advantages of high phase modulation speed, high regulation precision and wide regulation range. Compared to an acousto-optic modulator applied in an interference photoetching system, by reasonably laying out an optical structure, the system precision, graph contrast, focal depth and focal spot size are not influenced, and the light path of system is simple, thereby finally realizing the improvement of the whole performance of an interference photoetching system.