摘要:
In a system for writing a plurality of information tracks between adjacent portions of a reference track on a rotatable medium, advantage is taken of the fact that laser beam dithering a cross an edge of a reference track produces signals which are analyzable to determine much more exact radial positions. A pattern of bits is written on the medium with a known spacing between bits. This may be at the time of disk manufacture or later. As these bits are being read, a clock is started along with a bit counter. At this time, a precise determination is made of the radial position at which the read bits are present. From these values, angular and/or linear velocities are computed and stored on the medium. Collected over time, this information is useful for determining aging characteristics of the drive mechanism for the medium. Also, even one-time collection of this speed information is useful for determining the speed at which data was written so that the drive speed can be accurately controlled for read operations, for example.
摘要:
A laser beam is split into two beams. One beam is oscillatorily at a first frequency in a direction associated with control of beam focus within two or more layers of a rotatable information storage medium, that is, in a CD-ROM-like device. The second beam is oscillatorily varied at a second (different) frequency in a direction so that it moves back and forth across an edge of a reference track. Separate filters are used to examine the reflected light so as to simultaneously control positioning of the laser light source a long two axes.
摘要:
A method is provided for reading an information track, or a writable disk with reference tracks, almost immediately after the information track has been written. Precise control of the positioning of the laser source which provides the parallel beams for writing and reading, is accomplished by analysis of the electrical signal produced by a reference beam reflected from an edge of a reference track on the disk/medium. Oscillatory movement of this beam across a track edge produces the desired electrical signal for precise position determination, and hence, for precise position control.
摘要:
A photodetector and a threshold detector are employed to determine from which side (left or right) of an embedded track light is being reflected from. This information is encoded in the light signal reflected from a rotatable storage medium by oscillatorily moving a laser beam back and forth across an edge of the embedded track. A waveform detector provides a signal, based on the output of the photodetector, which provides an indication of distance away from the edge of a subject track. The output of the threshold detector and waveform detector drive an up-down counter which thus associates a unique binary number with each information track.
摘要:
A laser-writable information storage blank comprises a substantially planar disk made of a material which is susceptible to modification by impingement of laser radiation. The blank medium includes a metallic track pattern, preferably in the form of a spiral pattern. The track pattern provides two reference edges from which exact distances may be determined for writing and reading binary information stored between adjacent track portions.
摘要:
A laser beam is split into two beams. One beam is oscillatorily varied at a first frequency in a direction associated with control of beam focus within two or more layers of a rotatable information storage medium. The second beam is oscillatorily varied at a second (different) frequency in a direction so that it moves back and forth across an edge of a reference track. In the embodiment herein both beams, after reflection from the medium, are returned to the laser source which is also used as a photodetector. Separate filters are used to examine the electrical output of the photodetector/source so as to simultaneously control positioning of the laser light source along the axes.
摘要:
A method and system for enhanced demolding of injection molded optical devices are disclosed. In one embodiment the system includes a metal moldplate without a coat of release layer and a curing device that generates high intensity pulses of UV light. The method includes: providing a moldplate made of a predetermined moldplate material; directly injecting optical material into cavities of a moldplate without a release layer; rapidly curing the injected optical material with high intensity pulses of UV light such that a predetermined optical device is formed; and separating the thus formed optical device from the cavities of the moldplate due to a differential thermal expansion between the optical device material and the moldplate material.
摘要:
Methods and systems for fabrication of injection molded optical components. In one embodiment, a moldplate with cavities receives injected optical material within walls of the cavities. The cavities are designed with a geometric profile approximately corresponding to a optical profile of an optical element to be formed therein. When molten optical material is injected into the cavities of the moldplate, the injected optical material forms a meniscus due to surface tension between the optical material and the wall of the cavities. The meniscus thus provides a shape corresponding to the predetermined optical profile. The optical material is then rapidly cured with actinic radiation, and a desired optical element with high-precision dimensions is formed within the cavities of the moldplate. In some embodiments, the moldplate is spun such that the meniscus is adjusted to match the predetermined optical profile within a certain tolerance.
摘要:
Feedback control of a target system is provided which utilizes the imposition of a periodic modulating signal onto a command signal of a controller. The command signal with the period modulating signal imposed thereon is input to the target system to be controlled. A response of the target system to a manifestation of the periodic modulating signal in the command signal is detected, and a feedback signal is produced from the detected response. The periodic modulating signal and the feedback signal are processed together to produce an error signal, and the command signal is modified in accordance with the error signal to drive the current state of the target system toward a desired state, wherein the periodic modulating signal facilitates control of the target system.
摘要:
Feedback control of a target system is provided which utilizes the imposition of a periodic modulating signal onto a command signal of a controller. The command signal with the period modulating signal imposed thereon is input to the target system to be controlled. A response of the target system to a manifestation of the periodic modulating signal in the command signal is detected, and a feedback signal is produced from the detected response. The periodic modulating signal and the feedback signal are processed together to produce an error signal, and the command signal is modified in accordance with the error signal to drive the current state of the target system toward a desired state, wherein the periodic modulating signal facilitates control of the target system.