摘要:
A method for manufacturing an optical element comprises a step of press molding an optical element material 6 disposed between an upper press head (7) and its paired lower press head (8), wherein in the upper press head (7) and/or the lower press head (8) is formed a groove-like component that forms a non-cylindrical face or a cylindrical face as an optically effective component in the optical element material (6). This makes it possible to obtain an optical element with stable face shape precision, boosts productivity, and is also advantageous in terms of cost.
摘要:
A master information carrier has a shape pattern corresponding to an information signal array to be recorded on a magnetic recording medium, and the shape pattern is provided by arraying a ferromagnetic thin film deposited on a nonmagnetic substrate surface. The ferromagnetic thin film is either a soft magnetic film or semihard magnetic film having not more than 40 kA/m coercive force in track length direction of the information signals, and residual magnetization of the ferromagnetic thin film in the track length direction of the information signals is greater than coercive force of the magnetic recording medium. As a result, a master information carrier with superior magnetic recording performance can be obtained.
摘要:
A master information carrier comprises a substrate whose surface has an embossed pattern corresponding to an information signal. At least a surface of the protruding portion of the embossed pattern is made of a ferromagnetic material. A method for writing an information signal into a sheet or disk magnetic record medium with a ferromagnetic thin film or coating is performed by putting the surface of the magnetic record medium into contact with the master information carrier so as to write a magnetized pattern corresponding to the embossed pattern of the master information carrier into the magnetic record medium.
摘要:
An underlying layer is formed of Cr or the like on a glass substrate, and a magnetic layer is formed on the underlying layer by simultaneously sputtering a magnetic substance and a non-magnetic substance that does not form a solid solution with the magnetic substance in an atmosphere having a pressure of 30 mTorr to 75 mTorr. The magnetic recording medium comprises clusters, each of which is formed of aggregated magnetic grains, and a non-magnetic substance between the clusters. Each magnetic grain has a grain diameter of 5 nm to 20 nm. An average gap between the clusters is 1.5 nm to 5 nm. Thus, the present invention can provide a magnetic recording medium having a high S/N ratio that is suitable for high density recording.
摘要:
A magnetic head is provided with a protective film of chromium nitride on its sliding surface. The film thickness is set to have no adverse effect upon the electromagnetic conversion characteristics of the head, and the film has sufficient wear resistance not only against a magnetic tape having its sliding surface formed of iron oxide or other metallic magnetic substances, but also against a magnetic tape having its sliding surface formed of chrome oxide, the chrome oxide substance having a strong abrasion effect upon the magnetic head. The protective film has a compressive internal stress in a range of 10.sup.9 to 10.sup.11 dynes/cm.sup.2, a Knoop hardness of not less than 1500 kgf/mm.sup.2, a nitrogen composition ratio in a range of 20 to 60 atom %, and a film thickness in a range of 50 to 1000.ANG..
摘要:
A master information carrier with excellent durability is provided, for the use of static and a real lump-sum recording of digital information signals on magnetic recording medium. The master information carrier comprises a non-magnetic substrate on which a ferromagnetic film is disposed with an embossed pattern. Protrusions of the embossed pattern correspond to a disposition of the digital information signals.Recessed portions of the embossed pattern of the ferromagnetic film are filled with non-magnetic solid material. Alternately, A non-magnetic substrate has an embossed pattern and recessed portions of the embossed pattern correspond to a disposition of the digital information signals. A ferromagnetic film is filled in the recessed portions of the embossed pattern.
摘要:
A master information carrier comprises a substrate whose surface has an embossed pattern corresponding to an information signal. At least a surface of the protruding portion of the embossed pattern is made of a ferromagnetic material. A method for writing an information signal into a sheet or disk magnetic record medium with a ferromagnetic thin film or coating is performed by putting the surface of the magnetic record medium into contact with the master information carrier so as to write a magnetized pattern corresponding to the embossed pattern of the master information carrier into the magnetic record medium.
摘要:
A magnetic disk for a magnetic recording/reproduction device includes a magnetic head, wherein a magnetization bit-pattern corresponding to a preformat information signal is recorded beforehand on the magnetic disk, wherein the magnetization bit-pattern is recorded by contacting a surface of the magnetic disk with a surface of a master information carrier having a pattern corresponding to the preformat information signal, and a portion of the magnetization bit-pattern corresponding to at least one signal selected from a clock signal and a synchronous signal has a recording width that is larger than a recording track width of the magnetic head in a radial direction of the magnetic disk.
摘要:
A master information carrier comprises a substrate whose surface has an embossed pattern corresponding to an information signal. At least a surface of the protruding portion of the embossed pattern is made of a ferromagnetic material. A method for writing an information signal into a sheet or disk magnetic record medium with a ferromagnetic thin film or coating is performed by putting the surface of the magnetic record medium into contact with the master information carrier so as to write a magnetized pattern corresponding to the embossed pattern of the master information carrier into the magnetic record medium.
摘要:
A master-information magnetic recording apparatus for recording preformat information signals into a magnetic recording medium using a ferromagnetic film pattern formed on a master information carrier, in which the pattern corresponds to the preformat information signals. With the master information carrier in contact with the magnetic recording medium, the ferromagnetic film pattern is magnetized by a magnetic field applying device. Thus, the preformat information signals are recorded into the magnetic recording medium. The magnetic field applying device is so constructed that the direction of magnetizing the ferromagnetic film pattern is perpendicular to a track-scanning orbit of a magnetic head in a recording and reproducing apparatus in which the magnetic recording medium is installed. It enables the magnetic head to gain sufficient reproduction amplitude for track-scanning for reproducing the information signals.