Abstract: To protect access to information recorded on a light-readable disc, a light-readable disc player provides the user with a unique key each time the user attempts to play the disc. After the user communicates the unique key to a transaction service and satisfies certain preconditions, such as providing payment or account information, the transaction service provides the user with an unlock key. The user communicates the unlock key to the light-readable disc player, which plays the disc only if the user has provided the correct unlock key.

Abstract: A double sided (or higher multiple sided) data storing compact disc for optically recorded data has data surfaces that are separated by a thin film of wavelength selective material that passes light of one frequency and reflects light of a second (or multiple) frequency. The thin film either passively relies upon the inherent interference between light signals reflected from its upper and lower surfaces or is an active material that reflects light of one frequency and transmits light of a second frequency. A further aspect of the present invention is the method for the manufacture of such a multi-surfaced disc.

Abstract: A system and method are provided that allow an optical media inspection device to detect defects on or in optical media despite the presence of gross deformations in the media that would otherwise interfere with the inspection process. A holding device holds the optical media near the center while it is rotated for inspection. A negative displacement prohibitor impedes any negative displacement of the optical media. A positive displacement inhibitor, i.e., air pressure exerted on the optical media, holds the optical media substantially flat while it is being inspected. A closed-loop feedback system may be used to control the amount of air pressure exerted against the optical media.

Abstract: Information-bearing discs are fabricated from a first disc and a second disc. The first disc has a first substantially planar surface and a second surface opposite to the first surface. The second surface has first information recorded on it by means of local changes in the distance of the second surface from the first surface. The second disc is thicker than the first disc and has opposite, substantially planar, third and fourth surfaces. The fourth surface may have second information recorded on it by means of local changes in the distance of the fourth surface from the third surface. The second disc is secured to the first disc so that the fourth surface faces the second surface.

Abstract: A dual-layer DVD disc that does not require a stamping step (typically, as part of the 2P prior art manufacturing process) during its manufacture. A polycarbonate substrate is molded and coated with a semireflective data layer in the usual way. A PMMA substrate is molded and coated with a fully reflective data layer. Adhesive is placed on the semireflective data layer, and the fully reflective data layer is transferred from its PMMA substrate to the polycarbonate substrate. The polycarbonate substrate thus ends up with two data layers in conformance with the DVD specifications, and the PMMA substrate can even be recycled for another use.

Abstract: Methods and apparatus for making optical discs (e.g., for use in digital versatile discs ("DVDs") are provided. An optical disc made in accordance with this invention includes at least one roughened surface portion to mask any manufacturing irregularities and thereby improve the appearance of the disc and, if the disc is used in a DVD, then also the DVD. The method includes roughening a section of a mold in contact with molten plastic, molding an optical disc with that mold so that at least one side of the optical disc has a roughened surface portion, and if the disc is used in a DVD, securing the disc to another disc with adhesive to form a DVD.

Abstract: An improved light-readable information recording disc is provided in which the optical data storage structure consists of either lands and pits or lands and bumps, in which the depth of the pits or the height of the bumps, respectively, is controlled to approximate one-half of the wavelength of the light striking the optical data storage structure. Unexpected and surprising improvements over conventional optical recording discs is achieved through increased light intensity differences detected at the changeover between pits/bumps and lands.

Abstract: Artwork is imparted to plastic discs such as CDs, CD ROMs, and DVDs (digital video discs) by exposing a layer of photoresist material on a substrate to light from an original image of the artwork. The material of the photoresist layer is exposed to different depths by different intensity light from different image regions. Where the image is dark, the exposure is to relatively shallow, random depths. Where the image is light, the full thickness of the photoresist layer is exposed. Development of the photoresist layer removes the exposed photoresist material. The surface features of the developed photoresist layer and any uncovered substrate are transferred to a member used in forming a surface of the plastic disc, thereby visibly embossing the image in the disc.

Abstract: The present invention relates to a recording medium including video, audio and graphics information stored in separate sets of data packets and a method for creating the same. The graphic information can be superimposed on the video information during playback of the recording media. The graphic information can include text or images. The text has a translucent background and the images may be translucent in whole or in part.

Abstract: A system and method are provided that allow an optical media inspection device to detect defects on or in optical media despite the presence of gross deformations in the media that would otherwise interfere with the inspection process. A holding device holds the optical media near the center while it is rotated for inspection. A negative displacement prohibitor impedes any negative displacement of the optical media. A positive displacement inhibitor, i.e., air pressure exerted on the optical media, holds the optical media substantially flat while it is being inspected. A closed-loop feedback system may be used to control the amount of air pressure exerted against the optical media.

Abstract: To protect the optical surface of optical disc information recording media such as a compact disc (CD) or a digital versatile disc (DVD), that surface is coated with a removable layer of a material that does not significantly alter the optical properties of the disc. Whenever the coating layer may have become damaged, it is removed and replaced with a new layer.

Abstract: The warping of the surface of a composite compact disc occurring during the bonding of two surfaces together to form the disc is reduced by the use of a curing filter that modulates the intensity of the ultraviolet light used to set the bonding agent. The curing filter may be in the form of a disc having a greater density near the periphery of the disc than at the center.

Abstract: An in-line system for fabricating a double sided compact discs by bonding together an information bearing surface and another surface, has a prestressing station with means for deforming at least one of the surfaces in such away as to not disturb any of the data. It employs an adjustable spacer for maintaining an adjustable separation between symmetrical arcuate portions of the outer circumference of the information bearing surfaces in the bonding station. This adjustable spacer comprises two spacer arms that comprise wedge shaped portions for entry between the edges of said discs and maintaining a displacement of at least the outermost edges of said discs. There is also disc displacement means for bringing together the two information bearing surfaces by displacement of at least one of said information bearing surfaces orthogonal to the plane of the surfaces.

Abstract: Methods for bonding structurally asymmetrical or otherwise structurally dissimilar optical discs are provided. A bonded optical disc stack is formed from a first and a second optical disc by coating the back side of at least one of the optical discs with a light-curable bonding material and stacking the first and second optical discs back to back. The front side of the second optical disc is exposed to light for a first predetermined time period. The front sides of both the first and second optical discs are then exposed to light for a second predetermined time period. Finally, the front side of the first optical disc is exposed to light for a third predetermined time period. In this manner, when the second optical disc comprises program information and the first optical disc comprises a graphical image or other artwork, image pass-through due to simultaneous exposure and disc warpage due to one-sided exposure are significantly reduced.

Abstract: A container for an optical disc such as a compact disc (CD) or digital versatile disc (DVD) has a bottom structure, a top structure movable relative to the bottom structure, and a hub structure projecting up from the bottom structure. With the lid open, the central aperture of the disc is easily placed on or removed from the hub. In this condition the hub structure centers the disc in the bottom of the container but does not retain the disc in the container. When the lid is closed, however, the lid causes the hub structure to radially enlarge and secure the disc. Reopening the lid allows the hub to return to the condition in which it does not retain the disc.

Abstract: A process for determining the Start Program Point for a compact disc recording of data first recorded on an other medium, by measuring with the aid of a microscope the radius of the transition from the first pit/land transition from silence to data, measuring with the aid of an editor for the other medium a delay period of silence intended to be part of the data, calculating the Start Program Point and recording the Start Program Point thus calculated on the compact disc.

Abstract: A method for focusing the objective of an optical pick-up head on the desired information layer of an optical memory device. The focus error signal when the focus servo is in open loop mode is used to determine the location of the information layers (or layer) and to provide a mechanism for providing a signal which can be used to time/trigger the closing of the focus servo, thus providing focus on the desired layer. One example of an embodiment of the invention is an application to a dual layer optical disc.

Abstract: A system for testing compact discs having audio or video information and time subcode information indicating the elapsed time from the beginning of the audio, video or data information thereon in which three microprocessors respectively monitor the HF signal, the radial tracking signal and the decoder digital flags produced by a CD player to produce error signals indicating HF dropout, HF low, modulation amplitude, radial tracking, Burst, Bler, and uncorrectable errors and in which a computer having a memory responds to the time signal produced by the player periodically to transfer the contents of the microprocessors to the memory together with the time of transfer and to reset the microprocessors, thus to record errors and to locate the positions thereof on the disc in terms of the time subcode information. Initially an eccentricity test is performed and the entire test is stopped if the eccentricity is excessive. The computer is programmed to display the test results in various formats.

Abstract: A single or multi-sided, single or multi-layered optical data disc in which graphical information resides beneath all layers of data information, while maintaining playability. The graphical information is fully viewable to a user through the layers of data. The conventional metalization layer is replaced by a thin film dielectric coating that provides the reflectivity of the metal to the reading laser frequency while being highly transmissive of the ambient visible spectrum.

Abstract: Generic and specific artwork is imparted to plastic discs such as CDs, CD ROMs, and DVDs (digital video discs) by exposing a layer of photoresist material on a forming member, which already contains generic artwork, to light from an original image of specific artwork. The material of the photoresist layer is exposed to different depths by different intensity light from different specific image regions. Where the image is dark, the exposure is to relatively shallow, random depths. Where the image is light, the full thickness of the photoresist layer is exposed. Development of the photoresist layer removes the exposed photoresist material. The surface features of the developed photoresist layer and any uncovered forming member surface are transferred to a second forming member used in forming a surface of the plastic disc, thereby visibly embossing both generic and specific artwork in the disc.