Abstract: A diffractive lens constructed in accordance with the invention comprises a set of bands such that the diffractive gratings in each band are modified. This is done to ensure that even if the lens is tilted (e.g. to prevent light from reflecting off the lens and, introducing distortion into an optical system), the lens continues to focus light onto a small point on a target surface. (The target surface is typically an optical or magneto-optic data recording medium.

Abstract: A magneto optic or optical disk drive comprises a laser source for providing laser beam, and a lens or compound lens for focussing the laser onto a currently inserted recording disk with specific overcoat thickness. In one embodiment, the lens is a compound lens that can focus aberration-free spots on different types of disk media having recording layers located under overcoats of different thicknesses. When a specific disk is inserted, only one spot in focussed onto the current recording layer. Furthermore, if the disk spins rapidly, it can wobble. The lens or compound lens comprises different regions where the focal length may vary slightly and continuously or discretely. Because of this, as the disk wobbles, the lens can nonetheless continue to focus laser light onto a small spot on the recording media, providing increased depth of focus in the vicinity of the currently inserted recording media.

Abstract: A head slider for flying above a rotating magneto-optic or optical disk and an optical mechanical assembly with a fixed height above a rotating magneto-optic or optical disk contains magnetic coils and a lens plate with a diffractive optic structure for focusing laser light into a small spot on the disk. The diffractive optic structure may be a zone plate, a phase zone plate or a blazed phase zone plate or other diffractive focusing optical element. The diffractive optic structure does not require curved transparent material such as glass or a high index of refraction. The diffractive optic structure is easily manufactured using lithographic or other techniques.

Abstract: A method for forming a novel head used in magneto-optic or optical disks comprises the steps of forming a diffractive lens on one side of a glass substrate and forming air bearing surface rails on a second side of said glass substrate. The glass substrate is then cut into separate heads. In this way, many magneto-optic or optical heads can be formed simultaneously without incurring the expense of bonding lenses onto a slider. In one embodiment, coils are deposited on the substrate to generate a magnetic field during magneto-optic write operations. In another embodiment, a glass wafer having diffractive lenses formed thereon is bonded to a silicon spacer structure.

Abstract: A method of producing a high resolution expanded analog gray scale mask is described. Using an inorganic chalcogenide glass, such as a selenium germanium, coated with a thin layer of silver, a gray scale mask may be produced with accurate control of the size, uniformity and variance of the pixels. The selenium germanium glass is composed of column structures arranged perpendicularly to the substrate giving a possible edge precision of 100 .ANG.. The column structures also prevent undercutting during the etching process, thus permitting pixels to be placed close together. Accordingly, selenium germanium may be used as a high resolution gray scale mask with an expanded analog gray scale. The gray scale mask may be used to impress information as a modulated thickness on a selenium germanium photoresist layer on an inorganic substrate. The selenium germanium photoresist layer may then transfer the gray scale to the substrate.

Abstract: A method of producing a high resolution expanded analog gray scale mask is described. Using an inorganic chalcogenide glass, such as a selenium germanium, coated with a thin layer of silver, a gray scale mask may be produced with accurate control of the size, uniformity and variance of the pixels. The selenium germanium glass is composed of column structures arranged perpendicularly to the substrate giving a possible edge precision of 100 .ANG.. The column structures also prevent undercutting during the etching process, thus permitting pixels to be placed close together. Accordingly, selenium germanium may be used as a high resolution gray scale mask with an expanded analog gray scale. The gray scale mask may be used to impress information as a modulated thickness on a selenium germanium photoresist film on an inorganic substrate. The selenium germanium photoresist film may then transfer the gray scale to the substrate.