光盘系统中的伺服控制要求

1.引言光盘系统是光存储技术的典型代表之一。从上个世纪八十年代CD光盘的最初面市至今,经过30多年的发展,光盘系统已经在出版发行和信息存储领域中取得了广泛的应用,并在这期间衍生出了许多类型的物理和应用格式。在这些格式中,CD、DVD和BD这三大格式无疑是其中最具有代表性的光盘格式。     

为光盘加把锁 华硕光存储产品数据安全功能试用

光存储数据安全日益被刻录机厂商重视,目前只有少数几家光存储厂商涉足该领域,推出了光盘加密解决方案。华硕提供的光盘加密技术使用方便,更简单、灵活。另外,华硕光存储还创新推出E-Hammer技术,可彻底毁坏存储在光盘里的数据,为刻录机数据安全提供全新解决方案。     

面向21世纪的光盘技术

今年9月16日至19日,首届中国国际光盘复制存储设备展览会和光存储技术研讨会同时在京召开,会上世界光盘工业的著名公司及国内外专家学者云集,他们将交流世界光存储最新技术,展示最新光存储产品及设备,寻求与中国的合作和贸易机会,这对我国光盘产业的发展无疑将起到重要的推动作用,因此受到业界的广泛重视和关注。 光存储产品作为新一代多媒体信息记录传播载体,有着广阔的发展和应用前景。中国光盘生产量预计到2000年将形成近200～300亿元的产值,光盘技术已从计算机专业应用扩大到普通家庭,今后我国家庭中光盘机的拥有量将可能超过电视机。这将是一个在21世纪大有发展前途的新兴产业。 这里我们特约请此次大会的会议主席、国家光盘工程研究中心主任徐端颐先生,介绍世界光存储技术和光盘工业的发展趋势,并在“选购指南”栏目中请高宏博士和徐学雷博士撰写了《形形色色的光盘存储器》一文,希望对大家有所裨益。     

带主动倾斜补偿功能的混合型光学头三维力矩器

一、引言从CD发展到HD DVD、BD,光存储的数据容量和读写速度有了迅速的增长。大容量光存储需要减小盘面上的光斑尺寸,要求采用NA更高的物镜和波长更短的激光。然而,高NA物镜和短波长激光的使用会造成光盘倾斜容差的降低、盘片厚度公差的严格化、焦深的减小和球差的增加。这些变化可以通过以下各式表达:     

下一代光盘的专业应用道路

时至今日,虽然磁性存储产品的成本大幅度下降,但光盘依然是单位存储成本最低的随机访问存储介质。在可记录光盘诞生之初,许多存储厂商迅速推出自己的光存储战略和产品线,并试图在企业存储市场上与磁带机/ 库、光盘阵列分一杯羹。结果事与愿违,今天除了传统的5.25英寸MO 磁光盘在某些存档应用领域中占有一席之地,以及光盘塔应用于图书馆检索之外,大量的光存储产品都只是服务于个人备份和数据分享,难以进入企业应用的大门。原因很简单:光存储比磁带的单位成本低,但传输速度不如硬盘快。     

高密度光存储格式之争的新动向

今年五、六月以来,光盘产业界真可谓是好戏连 台,有关当今世界上最主要的两大未来高密度 光存储格式的研发和推广联盟——蓝光光盘(Blu-ray Disc,后面简称BD)阵营和HD DVD联盟将联手统一制 定DVD之后的下一代高密度光存储格式的话题一直     

在大容量光存储产业中构建以中国企业为主的第三方专利池的可能性(下)

五、前三代光存储产业主导者的特点第一代光存储技术的CD光盘规格,是飞利浦公司率先建立的;第二代光存储技术的DVD光盘规格,也是以飞利浦、松下、索尼、东芝等大公司牵头建立的;第三代光存储技术的BDA产业联盟中,有18家企业成为核心的理事会成员,它们也由飞利浦、松下、索尼、日立、先锋、夏普、JVC、TDK、迪斯尼、福克斯等大公     

一种用于高密度只读光盘的新型DPD循迹伺服方法

一、引言和其他存储设备领域一样,在光存储领域中对于更大存储容量的需求从未停止过,对于更高容量光存储系统的研究也在一直继续着。最近报道了一种基于蓝光光盘(Blu-ray Disc,BD)扩展的光盘系统,其容量达到了200GB。另外,研究人员还提出了单层容量     

通过原子力显微镜(AFM)对HD DVD压模进行分析

众所周知,HD DVD和Blu-ray Disc同属于第三代 光存储产品。和第一、二代光存储产品——CD光盘 和DVD光盘相比,HD DVD和Blu-ray Disc光盘中的特 征结构更小,对误差的公差容量也更小。例如,HD DVD光盘的结构中,平均道间距一般为400±10nm(复 制盘上),而对单独一张盘片而言,道间距的公差可     

笔记本电脑进入双核心时代——Intel下一代移动计算平台Napa前瞻

双层存储技术是最近两年光存储领域的主导技术，它可在同样大小的光盘上进行双屡数据写入到光盘的记录层上。在不改变光头波长和存储介质的情况下．轻松实现存储容量翻倍，这也是解决存光存储容积偏小的一个重要方案。     

Design of swing arm actuator for small and slim optical disc drives

Recent advancements in mobile devices have fueled a requirement for information storage systems with characteristics such as subminiature size, low cost, and minimum power consumption. Small optical disk drives could provide a good solution, because their storage media is cheaper than those of hard disk drives or flash memories. In this paper, we proposed the miniaturized swing arm type actuator that had a new focusing mechanism for small and slim optical disk drives (ODD). Initial model was designed by EM and structural analyses. Based on results of DOE, optimization procedures of EM circuits were performed with design variables using variable metric method (VMM). And, structural parts were designed to maintain the high sensitivity of the actuator. Finally, the swing arm type actuator for small and slim ODDs was suggested and its dynamic characteristics were checked.     

Auto-focusing actuator and camera module including flexible diaphragm for mobile phone camera and wireless capsule endoscope

Recent cellular phones have high-resolution, compact digital camera modules that have several millions of pixels. Although being small, such several mega-pixel camera modules definitely need to be able to execute auto-focusing and/or optical zooming in order to obtain precise images. Hence, image photographing devices having driving mechanisms that can move a lens group in the direction parallel to an optical axis have appeared such as piezoelectric type, linier motor type, and voice coil motor type. Although these technologies are already popular in existing digital cameras, driving mechanism for camera modules in cellular phones needs to be extremely improved because their requirements are totally different from usual digital cameras. Compact image photographing devices, which are installed in mobile apparatuses, should improve portability by reducing their sizes and weights and increase use-time of a battery by reducing power consumption. Weakened suspension (e.g. thickness is 0.02 mm or less) in order to minimize an elastic coefficient for drastic decrease of driving current frequently occurs permanent step-out of a lens group by plastic deformation of the metal suspensions when it comes to getting shocks from accidental drops of a handset. The proposed auto-focusing actuator using conductive polyimide as a flexible diaphragm satisfies these requirements of ultra slim cell phones. This polyimide suspension shows ultimate toughness when it comes to drop-test of cell phones. This actuator also shows high performance quite enough for several mega-pixel camera modules for ultra slim cellular phones; the moving range is up to 0.35 mm, the DC sensitivity is 0.2 mm/140 mA, and the resistance at the terminal is 22 Ohm, whereas the aperture is 6.8 mm, and the overall size is 10 × 10 × 3.95 mm. Most of all, the robustness against drop and shock has been dramatically increased, with no change of reliability under high temperature and high humidity condition, because of the flexibility of the conductive polyimide suspension.     

Development of symmetric type slim optical pickup actuator for flexible disk system

Recently, in information storage devices, several characteristics such as high data transfer rate, large storage capacity and small drive size are required as high-definition television (HDTV) broadcasting, mobile devices, and notebook personal computer (PC) were popularized. In optical disk drive (ODD), several actuators have been developed to satisfy these specifications. In this paper, we presented the symmetric type slim actuator with efficient tracking magnetic circuits for the flexible disk system. At first, electromagnetic (EM) circuits were designed to have big driving force for high sensitivities through design of experiments (DOE). And, in structural parts, we designed the actuator that had proper control bandwidth through several redesigns of moving parts. Consequently, the final model was fabricated and dynamic tests were experimented. And, it was checked that our actuator had a very high tracking sensitivity and could be applied to the flexible disk system.     

Micro thermal design of swing arm type small form factor optical pick-up system

New multimedia information environment requires smaller optical data storage systems. However, one of the difficulties in the design of small form factor (SFF) optical pick-up is to emit the heat which is usually generated from laser diode (LD). The generated heat may reduce the optical performance of the system as well as the lifetime of LD. Therefore, it is important to include the thermal consideration in the development of SFF optical pick-up system for the high performance and longer lifetime of LD. It is also necessary to analyze the thermal characteristics of LD by the micro heat transfer analysis. In this study, micro heat transfer analysis was performed using the finite element method for the 28 × 11 × 2 mm³ super slim swing-arm type actuator of the optical pick-up in the Blu-ray disk (BD) format. Two different materials were used for a swing-arm; a double layer structure of polycarbonate/steel and a single layer structure of aluminum. The heat generated from LD (80 × 400 × 600 μm³) ranges from 100 to 250 mW. The maximum temperature at the LD is 78.9°C for the case of polycarbonate/steel swing-arm optical pick-up when the heat generation and the convection coefficient are 250 mW and 25 W/m² K, respectively. On the other hand, it is 52.87°C for the case of aluminum swing-arm under the same conditions. The result of simulation indicates that the single layer structure of aluminum actuator is more suitable for the for the SFF optical pick-up in the viewpoint of heat release.     

Design of optical pickups by combining structural analysis and ray tracing

Recently, the demand for slim optical pickups has been increasing due to the expansion of the laptop PC market. As the optical pickups get thinner, they become less rigid, and the quality of the readout signals deteriorates due to thermal deformation. We developed a method to design an optical pickup with high reliability even under harsh conditions by using a combination of ray tracing and structural analysis. We applied this method to design a current DVD slim pickup, and achieved quality equal to that of half-height pickups.     

Self-adaptive fruit fly optimizer for global optimization

Natural Computing - A self-adaptive fruit fly optimization (SFFO) algorithm is presented for solving high-dimensional global optimization problems. Unlike the conventional self-adaptive swarm...     

Enhancement of PZT embedded swing arm actuator using integrated read/write performance and actuation

The current technological challenges associated with the rotary-type seesaw arm actuator for small-form-factor (SFF) disk drives are the small skew focusing, which causes off-axis aberrations and reduces optical quality. This article develops a novel design for a seesaw arm actuator and suspension assembly that is based on a micro-PZT actuator to position pickup head. Dual-stage actuation relaxes the dynamic requirement on the focusing stroke. The proposed actuator with a tilt-compensation mechanism uses a PZT bender to drive pickup head focusing. This combined system, optical module and dual stage actuator, is effectively self-aligned the optical axis for read/write performance in both experiment and simulation result. Finite element modeling and dynamic measurements reveal significant improvements in the actuator bandwidth with and without micro-PZT actuator compensation.     

微位移系统中压电陶瓷驱动器迟滞建模

针对超精密微位移系统中压电陶瓷驱动器的迟滞非线性问题,提出了一种基于遗传反向传播(BP)神经网络的压电陶瓷迟滞非线性建模方法.通过电涡流位移传感器获取压电陶瓷驱动器不同电压值下所对应的位移值;利用六次多项式拟合获得迟滞的数学模型,从而建立基于遗传BP神经网络的迟滞,模型.实验结果显示:该迟滞模型在神经网络测试下的最大误差为0.082 1 μm,平均绝对误差为0.0158 μm.表明,所建的迟滞模型能够较精确地反映出压电陶瓷驱动器的迟滞特性,同时为微位移控制系统设计提供了一定的理论基础.     

A swing arm actuator for a small form factor optical drive

Small form factor optical drives for mobile application require high performance actuators that satisfy tight geometrical size requirements. We have designed a swing arm type actuator that allows the integration of a complete miniaturized optical pickup unit on the actuator. The performance of the actuator has been simulated by the FEM method and is compared with experimental results. Finally the manufactured actuator was used to read out a Blu-ray ROM disc.     

基于虚拟仪器技术的力矩器特性测试仪

力矩器是光盘系统中的核心组件,其动态性能直接决定着光学头读写光盘的质量。本文基于力矩器低频段内特性参数的在线测试要求,提出了基于虚拟仪器技术的力矩器特性测试仪技术方案,完成了测试仪整体方案设计、硬件平台的搭建以及软件系统的应用开发。