摘要:
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.)
摘要:
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.
摘要:
A light emitting device includes a number of light emitting diode dies (LEDs) mounted on a shared submount and covered with a single lens element that includes a corresponding number of lens elements. The LEDs are separated from each other by a distance that is sufficient for lens element to include separate lens elements for each LED. The separation of the LEDs and lens elements may be configured to produce a desired amount of light on a target at a predefined distance. In one embodiment, the lens elements are approximately flat type lens elements, such as Fresnel, TIR, diffractive lens, photonic crystal type lenses, prism, or reflective lens.
摘要:
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. Furthermore, the increased depth of focus will also remedy problems related to the change in focal length of the lens with changes in wavelength of the laser source. Because some of these changes in wavelength occur abruptly, this is also a case in which the limited performance of the auto-focus tracking system would be overly burdened.
摘要:
A light emitting device includes a number of light emitting diode dies (LEDs) mounted on a shared submount and covered with a single lens element that includes a corresponding number of lens elements. The LEDs are separated from each other by a distance that is sufficient for lens element to include separate lens elements for each LED. The separation of the LEDs and lens elements may be configured to produce a desired amount of light on a target at a predefined distance. In one embodiment, the lens elements are approximately flat type lens elements, such as Fresnel, TIR, diffractive lens, photonic crystal type lenses, prism, or reflective lens.