Abstract:
An optical data storage system employing a data-modulated writing laser beam and a nonerasing reading laser beam of predetermined wavelength and optical media for such systems characterized by multiple layers whose optical characteristics and thickness are chosen to accomodate a prescribed writing and reading energy and wavelength and so provide an "anti-reflection" condition for unrecorded portions of the medium and a relatively higher reflectivity for recorded portions. A preferred optical medium includes a highly reflective aluminum layer, a relatively transparent polymer spacer layer overlying the reflective layer, and an optical absorber (recording) layer overlying the spacer layer. Overcoating structure is specified in some detail; e.g., as a "soft pad" layer (e.g., fluoropolymer) on the absorber, with a "Hard" layer (e.g., radiation-cured acrylic) laid over the "soft pad" as an outer protective overcoat. Also, the "spacer" may be rendered as such a " soft pad".
Abstract:
An optical storage system is contemplated, one employing a data-modulated writing laser beam and a non-erasing reading laser beam of predetermined wavelength. Improved optical media for such systems are described, these characterized by multiple layers whose optical characteristics and thickness are chosen to accomodate a prescribed writing and reading energy and wavelength and so provide an anti-reflection condition (2-AR) for unrecorded portions of the medium and a relatively higher reflectivity for recorded portions. A preferred optical medium includes a highly reflective aluminum layer (213), a relatively transparent polymer spacer layer (214), overlying the reflective layer (213), and an absorber layer (215) overlying the nucleation layer (ST), the absorber layer (215) being rendered in an island configuration, adapted to be so affected by the contemplated write beam as to "agglomerate" and better transmit the read beam.
Abstract:
A process for making a radiation-reflecting record carrier, such as a video disc, on which video and/or audio information is stored in an optically readable track in which reflective areas alternate with non-reflective areas, the two areas having different effects on a reading beam in a playback machine so that the information recorded on the carrier may be recovered. The non-reflective areas are formed as apertures in the reflective areas and the underlying substrate (100, 102) is preferably translucent. The disclosed process uses photographic techniques to form a master negative or positive, and to form record carrier replicas from the master. In one disclosed embodiment of the method and apparatus of this invention, a two-sided recording medium comprises two transparent substrates (100, 102), each of which supports a perforated metallic, reflecting layer (104, 106). The two substrates are held together by a layer of adhesive (108) disposed between the two reflecting layers (104, 106).
Abstract:
An optical disc adapted for realtime writing and reading with light of a single predetermined wavelength comprises a heat-deformable recording layer (33) overlying a reflective support (30). In contrast with prior art real-time optical discs in which the optical properties and nominal thickness of the recording layer are selected to maximize the difference in amplitude of light reflected respectively from recorded and non-recorded regions on the disc surface, the optical disc of the invention comprises a recording layer in which the optical properties and nominal thickness are selected so that the phase difference in light reflected respectively from recorded and non-recorded regions is substantially maximized, and so that a substantial portion of incident light is reflected from both recorded and non-recorded regions, whereby the detection of such phase difference is facilitated. Whereas the prior art discs require, for optimum signal-to-noise ratio, that the pits be of a depth substantially equal to the recording layer thickness and that the readout beam be focused to a spot size smaller than the pit size, no such requirements are attendent the optical disc of the invention. Moreover, gradual bleaching of the dye-binder material does not adversely affect the signal-to-noise ratio of the readout signal.
Abstract:
Die Erfindung betrifft einen optischen Datenträger in Form einer Scheibe. Der optische Datenträger umfasst - ein Substrat (2), das aus einem transparenten Material ausgebildet ist, und - eine Reflektionsschicht (3), die auf einer Oberfläche des Substrates aufgebracht ist, wobei aufgrund einer Struktur an der Grenzfläche des Substrates (2) und der Reflektionsschicht (3) kodierte digitale Daten von einer optischen Leseeinrichtung gelesen werden können. Der optische Datenträger zeichnet sich dadurch aus, dass das Substrat (2) aus Polymilchsäure ausgebildet ist, wobei die Polymilchsäure mit einem Anteil von zumindest 1 % rechtsdrehender Milchsäurebestandteile (D-PLA bzw. PDLA) ausgebildet ist.
Abstract:
An optical storage medium is provided. The optical storage medium may include a data layer and a curable hard coat layer secured to the surface of the data layer. The data layer may be read, written to, or both read and written to using a laser having a wavelength of less than about 650 nanometers. A method for securing a curable hard coat layer directly to a data layer and curing the hard coat layer is provided.
Abstract:
An information storage medium with a stabilised information layer and a method of stabilising the information containing layer is disclosed. The medium is comprising at least one information layer in a stack of layers, the information layer being a layer comprising a phase-change composition comprising Ge, Sb and Sn. The phase-change composition is further capable of supporting at least a first and a second structural phase, and wherein the structural phase of at least one of the least two structural phases is stabilised over time by adding a dopant to the phase-change composition, the dopant may be Se. The information storage medium may be an optical storage medium where the stabilisation is a stabilisation of a crystal phase so that the time development of the reflectivity of areas of the crystal phase is diminished, i.e. the jitter is diminished. Thereby reflectivity variations from areas crystallised at different time instants are diminished.