摘要:
A sliding part of a magnetic-field generator is configured to slide above and spaced from a surface of a loaded magneto-optical disk in a floating manner. A magnetic-field generating part, which provides a magnetic field to the magneto-optical disk, includes a magnetic pole disposed on a side of the sliding part such that the magnetic pole and the sliding part are positioned adjacent to each other in a radial direction of the surface of the loaded magneto-optical disk and such that the magnetic pole is located closer to a periphery of the magneto-optical disk than the sliding part. An entire flat end surface of the magnetic pole confronting the surface of the magneto-optical disk is generally parallel to and recedes from a slide surface of the sliding part such that the entire flat end surface is spaced further from the surface of the magneto-optical disk than the slide surface of the sliding part.
摘要:
The present invention relates to a magneto-optical recording medium, in which are provided at least a reading layer and a writing layer on a substrate. A track guide groove is formed in the medium so as to include in-groove portions and on-land portions. Pits are formed on a portion along the track longitudinally adjacent where an in-groove portion and where no guide groove exists. Pits are also formed in an on-land portion between the in-groove portions of the track guide groove. Only a portion where a temperature has been raised by optical beam irradiation is read, while a domain of a writing layer is copied on the writing layer, whereby a writing/reading operation can be effected with narrower track pitches.
摘要:
A magneto-optical recording and/or reading-out apparatus can record and read out information on and from a magneto-optical recording medium by the use of a laser beam. The apparatus includes a reflected beam detector, a comparator operatively coupled with the reflected beam detector, and a judgment unit operatively coupled with the comparator. The reflected beam detector detects the quantity of a laser beam reflected from the magneto-optical recording medium during recording. The comparator compares the quantity of the reflected laser beam with at least one reference value during the recording, thereby detecting an abnormality in the reflected laser beam. The judgment unit judges whether an area of the magneto-optical recording medium which has caused the abnormality is practically usable, in accordance with an output from the comparator and data to be recorded on this area.
摘要:
A magneto-optical disc according to the present invention has separate regions located between mutually adjacent recording tracks. In the separate regions, magneto-optical signals are impossible to record or smaller than the recording tracks. Therefore, it is possible to maintain a low erasing power that is constant even when conditions such as off-tracking, defocusing and changes of operating temperature occur. The present invention provides a magneto-optical disc, further, which in a light modulating system restricts the recording domain so as to improve the number of times the disc can be rewritten, providing a magneto-optical disk that is highly compatible with different drives. Further, the magneto-optical disk according to the present invention is provided such that a residual signal is not caused if recording power during overwriting is lower than the previous recording power in a magnetic modulating system, further improving compatibility.
摘要:
A magneto-optical disk unit has a first magnetic-field generator for generating a magnetic field corresponding to a frequency in a recording signal frequency band and a second magnetic-field generator for generating DC magnetic fields of both north-seeking and south-seeking poles in a non-contact manner with a loaded magneto-optical disk. The first magnetic-field generator has a slider part for sliding over a loaded magneto-optical disk in a floating manner using an aerodynamic effect. The unit further has a transfer driver for moving the first and second magnetic-field generators in a direction parallel to the loaded magneto-optical disk and a rotary plate for vertically moving the first magnetic-field generator. The unit also has a disk judging circuit for judging whether the loaded magneto-optical disk is of a magnetic-field-modulation overwritable type (first type) or an erase-operation-required type (second type), and a controller for controlling the rotary plate to bring the first magnetic-field generator into contact with the loaded disk when this disk is of the first type and to keep it raised from the disk when this disk is of the second type. The second magnetic-field generator is used when the disk is judged to be of the second type.
摘要:
A control device inputs reliability information on the same data block a plurality of times into a reliability storage memory. A reliability generating device generates a reliability information by performing computation processing based on a stochastic computation by using reliability information generated in the previous cycle that has been saved in the reliability storage memory and reliability information generated in the present cycle, and saves the reliability information generated in the reliability storage memory when the decoding is performed by using reliability information on the data block the same as that in the previous cycle. A column processing computation device computes a column processing output value by using the reliability information generated and saved in the reliability storage memory and a row processing output value.
摘要:
A method for inspecting an optical information storage medium includes the steps of: irradiating the storage medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities that include a first linear velocity Lv1 and a second linear velocity Lv2 higher than the first linear velocity Lv1; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam that irradiates the medium based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters for the focus and/or tracking error signal(s) to obtain residual errors of the focus and/or tracking error signal(s) and comparing the residual errors to predetermined reference values.
摘要:
The present invention provides a measure for getting read/write control information stored within a space of a predetermined size in a format that ensures compatibility with media of a lower order or an older generation even if the size of the read/write control information increases significantly as the storage densities of information storage media rise in the near future. On an information storage medium, a data sequence is writable as a combination of marks and spaces. The medium has at least one information storage layer, which has an information storage area to store information and a control information area for use to perform a read/write operation on the at least one information storage layer. The control information area stores at least one set of control information, which includes a first kind of write pulse information including information to be used as a reference value and a second kind of write pulse information including information to be used as an offset value. The size of the offset value is at least a half as large as that of the reference value.
摘要:
An optical information medium measurement method measures a degree of modulation in an optical information medium of a multilayered structure having a plurality of information layers. The method includes measuring the modulation degree of each layer of the optical information medium, obtaining a thickness between layers of the optical information medium, obtaining a reflectance of each layer of the optical information medium, and converting the modulation degree of each layer. The modulation degree is measured based on a value indicative of the thickness between layers, and a value indicative of the reflectance of each layer.
摘要:
Shape-wise thicknesses of a cover layer and first through (N−1)th intermediate layers of an optical recording medium having refractive indexes nr1, nr2 are converted into thicknesses t1, t2 of the respective layers having a predetermined refractive index which makes a divergent amount equal to a divergent amount of a light beam resulting from the thicknesses tr1, tr2, a difference DFF between the sum of a thickness “ti” through a thickness “tj”, and the sum of a thickness “tk” through a thickness “tm” is set to 1 μm or more (where i, j, k, and m are each any positive integer satisfying i≦j≦k≦m≦N), and the thicknesses t1, t2 are calculated by products of a function f(n) expressed by the following formula (1), and the thicknesses tr1, tr2: f(n)=−1.088n3+6.1027n2−12.042n+9.1007 (1) in the formula (1), n=nr1, nr2, . . . , and nrN.