Abstract:
The invention relates to a stamper for replication of optical discs and to a method of obtaining such a stamper. The method comprises the steps of: a) obtaining a substantially disc-shaped member (100) having a first surface (105; 106); and a second surface (112) forming a back surface of the semi-manufactured stamper; said first surface being provided with a guide track (6; 6') for indicating structurable surface portions (106') of said member (100; 130); said structurable surface portions (106') being flat and substantially unstructured; b) applying a layer (120; 240;) sensitive to irradiation on said first surface (105) such that an unexposed and exposable semi-manufactured stamper is provided; c) enclosing the unexposed semi-manufactured stamper in a protective package such that the sensitive film is maintained substantially unexposed; and d) treating (S30) the semi-manufactured stamper, before performing step c), said treatment including: d1) treating said second surface (112) of the semi-manufactured stamper such that a mean surface deviation value (Rz) below (2) micrometer is obtained.
Abstract:
Optical disc (20) having high-contrast images (22) in the information area (25) and a method for creating such images. The optical disc includes an information area, wherein the information area is defined as an area capable of containing data readable by an optical disc player. Data is contained within the information area. An optically viewable high-contrast image is formed within the information area. The method may include providing a previously recorded master optical disc (60), including a disc substrate (62) and a photosensitive layer (64) thereon. A portion of the photosensitive layer may be removed down to the substrate within the information area of the master disc using a masking process (67) to form the high-contrast image.
Abstract:
An optical disk comprises a mark train, which has at least one shortest mark (11) and at least one other mark (12), recording readable information by applying a light beam (13), wherein the shortest mark of the mark train has a width (W1) larger than that of the other mark (W2).
Abstract:
An optical disk (100) comprising two base plates with a thickness h joined to form a recording medium, at least one of which includes a reflecting layer for signal marks on its back. A laser beam (210) is applied to this optical disk (100) through an objective lens (203), and reflected light from the reflecting layer is detected by an optical detector (213). An output from this optical detector (213) is supplied to a signal reading unit (215) and to a focusing unit (216) which is adapted to detect a focusing error of the objective lens (203) and control the position of the objective lens (203) with respect to the optical disk (100). In this optical disk, a half-width DELTA lambda of a laser beam source satisfies the following expression: lambda 0 /(2h(n2 -NA ) ) f a focal distance of the objective lens, n2 a refractive index of the base plate material, dmax a maximum diameter of a laser spot light applied to a signal pit, and g a general functional expression for determining a maximum half width DELTA lambda which is determined on the basis of these lambda 0, NA, f, dmax.
Abstract:
A method of manufacturing a recording master, whereby at least a layer (6) of photosensitive material is provided on a substrate (2), is subsequently irradiated at selected locations with a light beam, and is then developed so as to endow it with localised depressions at the irradiated locations, a film (4) of dielectric material being disposed between the substrate (2) and the photosensitive material (6), whereby irradiation induces an optical standing wave of average intensity Ya in at least the photosensitive layer (6), the phase of which wave is thus embodied by choice of the thickness of the dielectric film (4) that its intensity Yi at the interface (14) between the layer (6) and the film (4) exceeds Ya.
Abstract:
Process for fabricating glass tooling with a featured surface. The method entails the steps of coating a polished surface of a glass blank with a continuous metal coating. A photoresist is applied, exposed, and developed in a desired pattern. Uncovered metal is etched away and the remaining metal provides a mask. The uncovered glass is plasma etched to feature the surface of the glass blank.