VOLUMETRIC-SWEPT DISPLAY SYSTEM BASED ON HELIX ROTATING SCREEN AND DMD

Based on the helix rotating screen and the digital micro-mirror device （DMD）, the former proto of volumetric-swept display system is improved. The 3-D display system adopting a helix rotating screen to construct an imaging space meliorate the defects, such as the smaller image space, the fewer voxels and the severer voxel overlap dead zone caused by planar rotating screen. DMD with spatial light modular （SLM） technology increases the transmission bandwidth of 3-D data in the voxel activation subsystem and activate multi-voxel once time. The volumetric-swept system based on helix rotating screen and DMD is developed. The experimental results show that the image space, the vision dead zone, the voxels on slice, and the voxel activation capacity of the designed proto are superior to the plane rotating screen system.

Model Implementation and Analysis of a True Three-dimensional Display System

To model a true three-dimensional(3D)display system,we introduced the method of voxel molding to obtain the stereoscopic imaging space of the system.For the distribution of each voxel,we proposed a four-dimensional(4D)Givone–Roessor(GR)model for state-space representation—that is,we established a local state-space model with the 3D position and one-dimensional time coordi-nates to describe the system.First,we extended the original elementary operation approach to a 4D condition and proposed the implementation steps of the realiza-tion matrix of the 4D GR model.Then,we described the working process of a true 3D display system,analyzed its real-time performance,introduced the fixed-point quantization model to simplify the system matrix,and derived the conditions for the global asymptotic stability of the system after quantization.Finally,we provided an example to prove the true 3D display system’s feasibility by simulation.The GR-model-representation method and its implementation steps proposed in this paper simplified the system’s mathematical expression and facilitated the microcon-troller software implementation.Real-time and stability analyses can be used widely to analyze and design true 3D display systems.

Three-photon-excited fluorescence of Tb^(3+)-doped CaO-Al_2O_3-SiO_2 glass by femtosecond laser irradiation

A near infrared to visible blue, green, and red upconversion luminescence in a Tb^3＋-doped CaO-Al2O3-SiO2 glass was studied, which was excited using 800 nm femtosecond laser irradiation. The upconversion luminescence was attributed to ^5D3→^7F5, ^5D3→^7F4, ^5D3→^7F3, ^5D4→^7F6, ^5D4→^7F5, ^5D4→^7F4, and ^5D4→^7F3 transitions of Tb^3＋. The relationship between upconversion luminescence intensity and the pump power indicated that a three-photon simultaneous absorption process was dominant in this upconversion luminescence. The intense red, green, and blue upconversion luminescence of Tb^3＋-doped CaO-Al2O3-SiO2 glass may be potentially useful in developing three-dimensional display applications.

体扫描显示系统中螺旋旋转屏及螺旋切片生成算法

为了改善平面旋转屏体扫描显示系统中存在的成像空间较小、体素数量较少和体素重叠死区严重等缺陷,系统采用螺旋旋转屏构建体3维显示系统的成像空间。根据螺旋屏旋转构成的成像空间的特点,提出了利用螺旋面的素线和3维模型的三角面片求交的算法生成螺旋切片。该算法根据螺旋旋转屏的不同旋转位置的角度信息,把3维模型离散成有序的螺旋切片序列。实验结果表明,螺旋旋转屏的性能优越以及所提出的算法方便有效。