Abstract: An improved method and apparatus for making 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. As proposed by Mueller, 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. However, instead of using a PMMA substrate that is larger than the polycarbonate substrate as proposed by Mueller, in the invention they have equal diameters. This allows conventional molding equipment to be used with no major changes.

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: 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: 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: Automatic process control of the optical disc bonding process is achieved by tacking the adhesive and deforming the composite prior to final bonding. A separator chuck is used to maintain the separation of the disc halves through tack curing and a disc deforming jig is used during final bonding to compensate for any tendency of the disc halves to deform during the bonding operation.