Abstract: Regarding a signal recorded with a first frequency in a recording area on a specific first recording layer and a signal recorded with a second frequency different from the first frequency in a recording area on a second recording layer which might cause interlayer crosstalk in relation to the first recording layer, a reproducing signal measurement method for a multilayer optical recording medium having at least three recording layers includes reproducing the signal recorded in the recording area on the first recording layer, separating signals recorded respectively with the first and second frequencies, discriminating signal amplitude of the first frequency and a maximum value in signal amplitude of the second frequency, and calculating a signal amplitude ratio between them to measure interlayer crosstalk contained in the signal reproduced from the recording area on the first recording layer. Thus, the interlayer crosstalk quantity caused by unnecessary light can be measured quantitatively.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: Provided is a recording and retrieval apparatus for a multi-layer optical disk. A multi-layer optical disk in which a plurality of recording layers and a single servo layer are combined to form a set is used. A spot for the servo layer and a spot for the recording layers are turned on in a time-sharing manner. Servo signal detection areas are formed discretely in the servo layer. The servo signal detection areas and data recording areas are provided so as not to overlap each other when viewed from the spot incident side. Thus, separation of data from each of the layers can be done by even a single photodetector without interference.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: An information recording medium including a plurality of layers for recording or reproduction of information by irradiation of light and a tracking error signal for determining a layer number being recorded in each of the plurality of layers. A modulation of the tracking error signal is different in each of the plurality of layers.

Abstract: A method for determining layers in a recording medium having a plurality of layers for the recording and reproduction of information using light irradiation. Each of the plurality of layers includes an emboss portion and a wobble region having wobbles of a predetermined frequency. Layer determination is carried out based on the ratio of the amplitude of a wobble signal obtained from the wobble region to the amplitude of a reproduction signal from the emboss portion.

Abstract: Disclosed here is an apparatus and method for realizing write/read of mass information by reducing cross-talk components that are apt to increase in narrow tracks when various disturbances and variations are recognized. In order to achieve the above object, the apparatus is provided with a plurality of equalizers for correcting frequency characteristics of signals reproduced from a plurality of spots, then outputs from those equalizers are subjected to a computing process to correct tap coefficients of the equalizers sequentially so as to minimize the influence of the subject cross-talk, thereby realizing stable reduction of the cross-talk components.

Abstract: The present invention achieves a disc recording and reproducing apparatus capable of using an inexpensive disc by loosening the tolerance of track offset of each layer of a multilayer optical disc, and capable of ensuring the reliability of the disc by relieving external forces exerted on the disc at the loading or unloading of the disc. A disc holder that rotates while holding a multilayer optical disc is configured of a non-moving part fixed to a rotating shaft, and a moving part. Actuators are used to drive the moving part having the optical disc fixed thereto relative to the non-moving part, thereby correcting the offset of a recording layer with respect to the rotating shaft.

Abstract: An information recording medium capable of displaying multiple labels and a storing case for the information recording medium are provided. The multiple labels are displayed by changing the labels to be displayed while selectively selecting information layers in a multi information recording medium. The medium has a function to receive either voltage or current, and the information layers selectively receive either voltage or current for changing the labels.

Abstract: To know whether recorded data has been deteriorated. In an information recording medium recording data in a data recording layer through a change in atom arrangement caused by energy radiation, monitor marks are being recorded in the data recording layer to monitor a deterioration situation. A user can know the deterioration situation of recorded data.

Abstract: Multicolor characters or pictures are written in an optical disk in a visible manner. The optical disk comprises a figure writing layer for writing a visible figure in addition to a data recording layer for recording data. Recording of user data in the data recording layer and the writing of a visible figure in the figure writing layer are performed using the same optical disk drive. In one example, the figure writing layer comprises phase change layers that are formed via protection layers in a region sandwiched between a pair of reflective layers. By writing figure data separated into individual basic colors in the phase change layers individually, a multicolor figure can be made visible.

Abstract: High-speed and high-density recording of a layer-selected optical disc are enabled with a small number of electrodes. A plurality of recording films that are independently selectable are disposed between a pair of electrodes 3 and 8. The recording films are controlled individually in terms of a threshold of voltage required for coloration and electric characteristics. A desired layer can be selected by changing the voltage applied between the pair of electrodes.

Abstract: Multilayered optical recording media having three or more recording layers used to require spacing between recording layers to be accurately controlled to cope with the effect of crosstalk attributable to multiple reflections at plural recording layers. Making reflectivity at a backside of each recording layer lower than reflectivity at a front side thereof can reduce the effect of multiple reflections without requiring technology for highly accurately controlling interlayer spacing, so that medium production cost can be greatly reduced.

Abstract: A multilayer optical recording apparatus excellent in high-speed recording and long-term reliability is realized, the apparatus preventing the lowering of a speed of switching recording layers by preventing an increase in contact resistance attributable to wear of a rolling part or of a sliding part of the apparatus. In a multilayer optical recording apparatus using an electrochromic material, a rotary transformer is provided as electromagnetic induction means for supplying power from a power source to a medium.

Abstract: When external and internal environmental variation factors (characteristics of medium, variation in voltage, deterioration of medium and the like) occur, a reproduced signal is varied. In a learning system for reproduction of a voltage layer selection type multi-layer optical disk which making recording or reproducing by irradiation of energy, a level and/or pattern of an application voltage is adjusted in accordance with a reproduced signal at a predetermined position. Even if the reproduced signal, from the reflectivity down, is varied due to the external and internal environmental variation factors (characteristics of medium, variation in voltage, deterioration of medium and the like), the reproduced signal with the high quality can be obtained from the voltage layer selection type medium.