Abstract: A light generating apparatus includes: a submount; a semiconductor laser chip mounted on the submount; a substrate which is mounted on the submount and includes an optical waveguide; and a substance having a predetermined thickness which is disposed between the semiconductor laser chip and the substrate. In an oscillation wavelength stabilizing apparatus for a light source, the light source is a semiconductor laser which includes: an active region for providing gain; and a distributed Bragg reflection (DBR) region for controlling an oscillation wavelength.

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: An optical recording device comprises: a basic pulse generator 60 including a starting-end pulse generation circuit 2, a burst gate generation circuit 4, and an end pulse generation circuit 6; a data-length detector 61 including a front mark detector 40, a front space detector 41, a recording mark detector 42, a back space detector 43 and a back mark detector 44; a timing controller 62 including a starting-end pulse selecting circuit 14, a starting-end starting position setting circuit 15, a starting-end pulse delaying circuit 19, an end pulse selecting circuit 21, an end starting position setting circuit 35 and an end pulse delaying circuit 25; a pulse synthesizer 63 including an AND gate 27 and an OR gate 36; and a laser driver 64 including an erasing current source 32, a recording current source 33, and a switch 34.

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 plurality of types of recording pulse control rules for which the recording pulse waveform is determined according to the information signals to be recorded are stored in advance in an optical disk. When recording to the optical disk, information is recorded using a recording pulse where, due to the focused laser beam, the temperature in the recording layer cools more rapidly at a second information recording layer closer to the side where light is incident than at a first information recording layer farther away from the side where light is incident.

Abstract: There are some cases that an accuracy is low for reading unique information identifying an individual from an optical disk which comprises a plurality of information layers.

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 recording medium of the present invention includes a substrate (202), a protection plate (205), and a plurality of information layers (203) sandwiched between the substrate and the protection plate. An information signal is recorded as a length of a mark and a length of a space between two marks. The mark is formed when the information layer is irradiated by light received through the substrate. The information layers have a management region (206) recording a leading edge recording condition and a trailing edge recording condition. The leading edge recording condition is used to change a recording start position for forming a leading edge of the mark. The trailing edge recording condition is used to change a recording end position for forming a trailing edge of the mark. Each of the leading and trailing edge recording condition is depending on which information layer is recorded.

Abstract: A rewriteable type optical recording medium for recording information has an information recording area for recording information and a recording/reproduction condition recording area for recording at least one recording/reproduction condition to be used in a recording/reproduction apparatus and at least one set of apparatus information for identifying a recording/reproduction apparatus which uses the at least one recording/reproduction condition. A plurality of recording/reproduction conditions and a plurality of sets of apparatus information, each one the plurality of sets of apparatus information corresponding to one of the plurality of recording/reproduction conditions, can be recorded on the rewriteable type optical recording medium and overwritten on the rewriteable type optical recording medium.

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: An apparatus for writing on and reading an overwritable optical disk comprises an identifier detector that identifies a recording condition in the sector to be overwritten, and a delay time controller circuit that sets a variation range of the start point for writing according to the recording condition. The record timing of the modulated data signal is changed at random within the set variation range when overwriting the sector of the optical disk.

Abstract: An optical information recording medium includes a plurality of recording layers, a reflectance of at least one of the plurality of the recording layers in a non-initialized state with respect to a light beam for initialization being smaller than a reflectance of the same in an initialized state with respect to the light beam for initialization. The recording layers are initialized by irradiating, among the plurality of recording layers, the recording layer positioned farther from a light beam irradiation side with the light beam prior to irradiating the recording layer positioned closer to the light beam irradiation side, so that the initialized recording layers have no initialization irregularities.

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: An information recording device that records information on an optical recording medium includes: a laser beam generation device for generating a pulse light with a pulse width less than 1 ns; and a mark formation device for collecting the pulse light and irradiating a recording layer in the optical recording medium with the pulse light so as to form a mark in the recording layer, whereby generation of re-crystallization regions and a variation in the position of marks can be controlled appropriately and information can be recorded on an optical recording medium at high density.

Abstract: An apparatus for writing on and reading an overwritable optical disk comprises an identifier detector that identifies a recording condition in the sector to be overwritten, and a delay time controller circuit that sets a variation range of the start point for writing according to the recording condition. The record timing of the modulated data signal is changed at random within the set variation range when overwriting the sector of the optical disk.

Abstract: A rewriteable type optical recording medium for recording information has an information recording area for recording information and a recording/reproduction condition recording area for recording at least one recording/reproduction condition to be used in a recording/reproduction apparatus and time information representing a date on which the at least one recording/reproduction condition was recorded. A plurality of recording/reproduction conditions and a plurality of time information, each one the plurality of time information corresponding to one of the plurality of recording/reproduction conditions, can be recorded on the rewriteable type optical recording medium and overwritten on the rewriteable type optical recording medium.

Abstract: A recording and reproduction apparatus for a recording medium including a plurality of information layers includes a focusing signal generation section for generating focusing signals F+ and F− in accordance with a light beam reflected by the recording medium; a focusing control section for generating a focusing error signal in accordance with a difference between the focusing signals F+ and F−, and performing focusing control for maintaining a distance between a focal point of the light beam and a target information layer within a prescribed tolerable range; and a gain setting section for setting a focusing servo gain in accordance with the focusing error signal. The focusing signal generation section generates the focusing signals F+ F− so that values of components thereof based on the light beam reflected by an information layer other than the target information layer are substantially equal while focusing control is being performed.

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.