专利快速检索-快速检索全球专利，免费商用专利数据库-IPRDB

1. 发明专利

CA2066087A1 MAGNETO-OPTICAL RECORDING MEDIUM 未知
公开(公告)号：CA2066087A1
公开(公告)日：1992-10-18
申请号：CA2066087
申请日：1992-04-15
申请人： TAKAHASHI AKIRA , MURAKAMI YOSHITERU , NAKAJIMA JUNSAKU , OHTA KENJI , NAKAYAMA JUNICHIRO , KATAYAMA HIROYUKI , MIEDA MICHINOBU
发明人： TAKAHASHI AKIRA , MURAKAMI YOSHITERU , NAKAJIMA JUNSAKU , OHTA KENJI , NAKAYAMA JUNICHIRO , KATAYAMA HIROYUKI , MIEDA MICHINOBU
IPC分类号： G11B11/10 , G11B11/105
摘要： A magneto-optical recording medium has a recording layer whereon information is magneto-optically recorded. A readout layer is provided on the recording layer. The readout layer has a compensating temperature that is located between room temperature and the Curie temperature. In the readout layer, upon an application of a light beam, the in-plane magnetization occurs at room temperature and a transition from the in-plane magnetization to vertical magnetization occurs as the temperature of the irradiated area of the readout layer rises above a predetermined temperature. By employing this magneto-optical recording medium, with an application of a light beam that is intensity modulated into two levels, only a spot having a temperature not less than a predetermined temperature is involved in the reproduction; therefore, a recorded bit with a size smaller than the diameter of the light beam can be reproduced, thereby greatly increasing the recording density. Further, the level of the reproduced signals is increased, and crosstalk from the adjoining tracks is reduced; thus, information recording and overwriting can be conducted more easily.

2. 发明专利

CA2037428A1 REPRODUCING OPTICAL DEVICE FOR A MAGNETO-OPTICAL RECORDING MEDIUM 未知
公开(公告)号：CA2037428A1
公开(公告)日：1991-09-06
申请号：CA2037428
申请日：1991-03-01
申请人： TAKAHASHI AKIRA , MURAKAMI YOSHITERU , NAKAJIMA JUNSAKU , OHTA KENJI
发明人： TAKAHASHI AKIRA , MURAKAMI YOSHITERU , NAKAJIMA JUNSAKU , OHTA KENJI
IPC分类号： G11B11/105 , G11B7/00 , G11B11/10
摘要： A reproducing optical device for a magneto-optical recording medium related to the present invention having light sources that emit linearly polarized lights towards a magneto-optical recording medium, polarization directions of the linearly polarized lights being mutually orthogonal. A quarter wavelength plate disposed between the recording medium and the light sources converts each of the linearly polarized lights into right and left circularly polarized lights respectively. Corresponding to recorded information, the recording medium has magnetized sections that are magnetized in a perpendicularly upward and downward direction with respect to a medium surface. Moreover, the recording medium displays the property of circular dichroism. When the right circularly polarized light and the left circularly polarized light are reflected off the recording medium, a first and a second photodetector generate a first and a second reproduced signal respectively, based on variation in reflected light intensity of each of the circularly polarized lights. This variation corresponds to the upward and the downward magnetization directions of the magnetized sections and is due to the circular dichroism effect. There is a phase difference of half a cycle between the first and the second reproduced signal and the signals vary inversely with respect to each other. Consequently, disk noise is cancelled by differentially amplifying the first and the second reproduced signal, and an SN ratio of a reproduced signal thereby can be improved.

3. 发明专利

CA2073321A1 OPTICAL HEAD DEVICE 未知
公开(公告)号：CA2073321A1
公开(公告)日：1993-01-09
申请号：CA2073321
申请日：1992-07-07
申请人： TAKAHASHI AKIRA , MURAKAMI YOSHITERU , NAKAJIMA JUNSAKU , OHTA KENJI
发明人： TAKAHASHI AKIRA , MURAKAMI YOSHITERU , NAKAJIMA JUNSAKU , OHTA KENJI
IPC分类号： G11B11/10 , G11B11/105 , G11B7/125
摘要： A magneto-optical disk (23) has a recording layer (4) whereon recorded bits are formed by the magnetic field modulation method and a readout layer (3) whose axis of easy magnetization is parallel to the recording layer (4) at room temperature, and varies to be perpendicular to the recording layer (4) within a predetermined temperature range between room temperature and the Curie temperature. During reproduction of recorded bits a first semiconductor laser (10) emits a heating-use light beam (7) to form the first light spot on the readout layer (3). Thus, a ring-shaped region corresponding to the predetermined temperature range exhibits perpendicular magnetic anisotropy and the recorded bits are copied from the recording layer onto the ring-shaped region. As the first light spot is shifted, the ring-shaped region as a readout window of recorded bits is also shifted. Further, the second semiconductor laser (11) emits a reproduction-use light beam (8) such that the second light spot is formed on the readout layer (3) to overlap the first light spot at a rear portion thereof. Consequently, only one recorded bit copied onto the rear portion of the ring-shaped region can be reproduced. Therefore, high-quality reproduction signals can be obtained from the magneto-optical disk (23) inspite of information high density information recording.

4. 发明专利

CA2066076A1 CARTRIDGE FOR ACCOMMODATING FLEXIBLE OPTICAL DISK 未知
公开(公告)号：CA2066076A1
公开(公告)日：1992-10-20
申请号：CA2066076
申请日：1992-04-15
申请人： INUI TETSUYA , MIEDA MICHINOBU , NAKAJIMA JUNSAKU , OHTA KENJI
发明人： INUI TETSUYA , MIEDA MICHINOBU , NAKAJIMA JUNSAKU , OHTA KENJI
IPC分类号： G11B7/24 , G11B11/105 , G11B23/00 , G11B23/03 , G11B23/033 , G11B23/50 , G11B23/04
摘要： An optical disk cartridge for accommodating a flexible optical disk, comprising: a light transmitting window which is used for recording, reproducing or erasing signals on the optical disk accommodated in the optical disk cartridge; the light transmitting window being formed into a substantially arcuate shape having a central angle of 45.degree. to 120.degree.; the optical disk being constituted by a flexible film, an optical recording medium formed on the film, a light transmitting protective film for covering the optical recording medium and a center hub secured to a central portion of the optical disk.

你已经成功收藏专利！

检索式保存成功!

IPRDB

热门服务

关于我们

友情链接

联系方式