Abstract: The present invention relates to a recording and reproducing method and apparatus for an optical disk of the phase transition type that can be overwritten. According to this invention, the capacity of repeated rewriting of the optical disk is expanded by recording either non-inverted write data or inverted write data at random. The deterioration due to the repeated rewriting at a start point and an end point of the recording is suppressed by recording a synchronizing signal before the write data and/or dummy data after the write data in the way such that thermal stress is less likely to occur. A record end position can be determined precisely by detecting a stop pulse to stop recording.

Abstract: An optical information recording and reproducing apparatus for recording and reproducing an information signal on/from both concave portions and convex portions of guide grooves formed on a recording medium is disclosed.

Abstract: In an optical information recording medium having at least two information layer, guide grooves for tracking or sample pits or information pits corresponding to information signals are formed on a surface of a first substrate. A first information layer formed by a thin film for reflecting a portion of a light beam made incident on the first substrate and permitting penetration of a portion of the light beam is formed on a surface of the first substrate. Guide grooves for tracking or information pits corresponding to information signals are formed on a surface of a second substrate. A second information layer having a reflectance higher than that of the first information layer is formed on a surface of the second substrate. Between the first information layer and the second information layer, there is formed a transparent separation layer for positioning the first information layer and the second information layer to be spaced a predetermined distance apart from each other.

Abstract: Tracking control is carried out by a push-pull method or by mechanical feed at the time of recording signals, and tracking control is carried out by a phase difference tracking method at the time of reproduction. Thus, a phase change type optical disk which enables phase difference reproduction and is erasable may be realized. In a phase change type optical disk having a phase difference reproduction structure, servo mechanism at the time of reproducing signals may be stably controlled by causing the reflectance of a blank portion to be higher than the reflectance of a recording mark portion.

Abstract: An optical information recording medium has a first information layer composed of at least three thin films, which is capable of reflecting a portion of incident light and permitting the passage of a portion of incident light. The optical recording medium also has a second information layer composed of at least four thin films. Information can be recorded on or reproduced from the second information layer with light that has passed through the first information layer. The first and second information layers are separated by a transparent separation layer. The first information layer may be composed of a first dielectric layer, a recording layer and a second dielectric layer, and the second information layer may be composed a third dielectric layer, a second recording layer, a fourth dielectric layer and a reflecting layer.

Abstract: The present invention relates to a recording and reproducing method and apparatus for an optical disk of the phase transition type that can be overwritten. According to this invention, the capacity of repeated rewriting of the optical disk is expanded by recording either non-inverted write data or inverted write data at random. The deterioration due to the repeated rewriting at a start point and an end point of the recording is suppressed by recording a synchronizing signal before the write data and/or dummy data after the write data in the way such that thermal stress is less likely to occur. A record end position can be determined precisely by detecting a stop pulse to stop recording.

Abstract: Tracking control is carried out by a push-pull method or by mechanical feed at the time of recording signals, and tracking control is carried out by a phase difference tracking method at the time of reproduction. Thus, a phase change type optical disk which enables phase difference reproduction and is erasable may be realized. In a phase change type optical disk having a phase difference reproduction structure, servo mechanism at the time of reproducing signals may be stably controlled by causing the reflectance of a blank portion to be higher than the reflectance of a recording mark portion.

Abstract: The present invention relates to a recording and reproducing method and apparatus for an optical disk of the phase transition type that can be overwritten. According to this invention, the capacity of repeated rewriting of the optical disk is expanded by recording either non-inverted write data or inverted write data at random. The deterioration due to the repeated rewriting at a start point and an end point of the recording is suppressed by recording a synchronizing signal before the write data and/or dummy data after the write data in the way such that thermal stress is less likely to occur. A record end position can be determined precisely by detecting a stop pulse to stop recording.

Abstract: An optical information recording and reproducing apparatus for recording and reproducing an information signal on/from both concave portions and convex portions of guide grooves formed on a recording medium is disclosed.

Abstract: The present invention relates to a recording and reproducing method and apparatus for an optical disk of the phase transition type that can be overwritten. According to this invention, the capacity of repeated rewriting of the optical disk is expanded by recording either non-inverted write data or inverted write data at random. The deterioration due to the repeated rewriting at a start point and an end point of the recording is suppressed by recording a synchronizing signal before the write data and/or dummy data after the write data in the way such that thermal stress is less likely to occur. A record end position can be determined precisely by detecting a stop pulse to stop recording.

Abstract: An optical information recording and reproducing apparatus for recording and reproducing an information signal on/from both concave portions and convex portions of guide grooves formed on a recording medium is disclosed.

Abstract: A recording and reproducing method and apparatus for an optical disk of the phase transition type is provided. This method comprises the steps of deciding at random to invert or not to invert write data that has a predetermined block length; inverting the write data if the decision is to invert the write data; and recording either the non-inverted write data or the inverted write data into the photo-sensitive record layer. A synchronizing signal is recorded before the write data and/or dummy data after the write data in the way such that thermal stress is less likely to occur. A record end position can be determined precisely by detecting a stop pulse.

Abstract: In an optical information recording medium having at least two information layer, guide grooves for tracking or sample pits or information pits corresponding to information signals are formed on a surface of a first substrate. A first information layer formed by a thin film for reflecting a portion of a light beam made incident on the first substrate and permitting penetration of a portion of the light beam is formed on a surface of the first substrate. Guide grooves for tracking or information pits corresponding to information signals are formed on a surface of a second substrate. A second information layer having a reflectance higher than that of the first information layer is formed on a surface of the second substrate. Between the first information layer and the second information layer, there is formed a transparent separation layer for positioning the first information layer and the second information layer to be spaced a predetermined distance apart from each other.

Abstract: A multi-layer optical information recording medium has a first information layer located at the incident side for a laser beam and another information layer at the back thereof. Thus, it has a large capacity. A relationship that R1a<R1c and R2a<R2c holds for the reflectances R1a and R1c of the information layer in the in a recorded portion and in a non-recorded portion, and the reflectances R2a and R2c of the information layer in a recorded portion and in a non-recorded portion. A relationship that A1a<A1c holds between the absorptances A1c and A1a of the first information layer in the crystalline state and in the amorphous state, similarly, a relationship A2a<A2c holds between absorptances A2c and A2a of the second information layer in the crystalline state and in the amorphous state. Thus, signals can be written to the recording medium at a fast speed and at high sensitivity.

Abstract: An optical information recording and reproducing apparatus for recording and reproducing an information signal on/from both concave portions and convex portions of guide grooves formed on a recording medium is disclosed.

Abstract: In an optical information recording medium having at least two information layer, guide grooves for tracking or sample pits or information pits corresponding to information signals are formed on a surface of a first substrate. A first information layer formed by a thin film for reflecting a portion of a light beam made incident on the first substrate and permitting penetration of a portion of the light beam is formed on a surface of the first substrate. Guide grooves for tracking or information pits corresponding to information signals are formed on a surface of a second substrate. A second information layer having a reflectance higher than that of the first information layer is formed on a surface of the second substrate. Between the first information layer and the second information layer, there is formed a transparent separation layer for positioning the first information layer and the second information layer to be spaced a predetermined distance apart from each other.

Abstract: An optical information recording and reproducing apparatus for recording and reproducing an information signal on/from both concave portions and convex portions of guide grooves formed on a recording medium is disclosed.

Abstract: In an optical information recording medium having at least two information layer, guide grooves for tracking or sample pits or information pits corresponding to information signals are formed on a surface of a first substrate. A first information layer formed by a thin line for reflecting a portion of a light beam made incident on the first substrate and permitting penetration of a portion of the light beam is formed on a surface of the first substrate. Guide grooves for tracking or information pits corresponding to information signals are formed on a surface of a second substrate. A second information layer having a reflection higher than that of the first information layer is formed on a surface of the second substrate. Between the first information layer and the second information layer, there is formed a transparent separation layer for positioning the first information layer and the second information layer to be spaced a predetermined distance apart from each other.

Abstract: The present invention is to provide a method for manufacturing the PCE optical information recording disk under control of not only the crystallization velocity but also the complex index of refraction and thus the reflectance on the disk surface.The PCE optical information recording disk is suitable to be used under the constant angular velocity (the constant rotational numbers wherein the disk has a characteristic that the crystallization velocity is designed to become faster from inside area of the disk to outside area in the radical direction thereof under control of not only the crystallization velocity but also the complex index of refraction and thus the reflectance on the disk surface.

Abstract: The present invention is to provide a method for manufacturing the PCE optical information recording disk under control of not only the crystallization velocity but also the complex index of refraction and thus the reflectance on the disk surface.The PCE optical information recording disk is suitable to be used under the constant angular velocity (the constant rotational numbers wherein the disk has a characteristic that the crystallization velocity is designed to become faster from inside area of the disk to outside area in the radical direction thereof under control of not only the crystallization velocity but also the complex index of refraction and thus the reflectance on the disk surface.