Abstract: A tracking error detecting method comprises the steps of causing intensity distributions of single light introduced into an objective lens to have symmetry with respect to the track direction of an optical recording medium and the direction oblique to the direction perpendicular to the track direction, dividing a light-receiving unit into at least light-receiving units of the track direction and light-receiving units of the direction perpendicular to the track direction and detecting a tracking error signal based on detection signals from the divided light-receiving units.

Abstract: A stamper which has a region information according to a destination is set to the resin molding machine for HDDVD and the resin molding machine for DVD, respectively. The contents information (contents A) of the same program is held in each stamper. The region information of each stamper is different according to the destination of contents information. Two disc substrates to which the information on each stamper is transferred are formed using the resin molding machine for HDDVD and the resin molding machine for DVD, and the reflecting layer is further formed on the transfer face of each substrate by sputtering. And as the reflecting layer side faces each other, each disc substrate is laminated. Thereby, hybrid type next-generation DVD from which the destination of the contents information of a HDDVD layer and a DVD layer is different is manufactured.

Abstract: A recorder has a recording head which uses light for information recording to a recording medium. The recording head has a slider and an optical waveguide. The slider moves relative to the recording medium while floating thereon. The optical waveguide is provided in the slider and has a refractive index difference of 20% or more between a core and a cladding.

Abstract: When a hybrid type next-generation DVD is loaded in the optical disc device, first, a red laser is turned on and parameter value and a lead-in information with respect to a DVD layer are acquired. The acquired information is stored in a memory. Next, a blue laser is turned on, parameter value and a lead-in information to a HDDVD layer are acquired, and the acquired information is stored in a memory. Then, the HDDVD layer is reproduced while lighting of the blue laser beam is maintained. Then, when a jump instruction to the DVD layer is inputted, the parameter value for the DVD layer is read from the memory and set to a process system. And the lighting laser is changed to the red laser and reproduction of the DVD layer is performed based on the lead-in information of the DVD layer stored in the memory.

Abstract: It is possible to obtain preferable recording characteristic and reproduction characteristic by considering irregularities of unique characteristics of an LD or the like mounted on an information recording and reproduction apparatus as well as characteristics of an optical disc used. In the information recording and reproduction apparatus, a light source such as a laser diode is driven by a laser drive signal so that a laser beam for recording or reproduction is emitted from the light source. Moreover, the laser drive signal is superimposed by a high-frequency signal of a predetermined frequency so as to eliminate effect of the return light from the optical disc. The information recording and reproduction apparatus superimposes the high-frequency signal by using a high-frequency signal level during recording which is different from a high-frequency signal level during reproduction.

Abstract: An optical system is disclosed including an optical pickup having a wavefront aberration-correcting element capable of correcting coma aberration and astigmatism, and an optical disc apparatus which uses the optical pickup. The optical pickup includes a laser light source for irradiating an optical disc with a light beam; an objective lens for focusing the light beam on the optical disc; a lens for correcting astigmatism; a second lens for correcting coma aberration; and a photodetector for receiving the light beam reflected from the optical disc. The astigmatism and the coma aberration are corrected independently of each other.

Abstract: Disclosed is a playback device capable of audio playback with little or no interruption. Yet, there is no need of increasing the memory capacity of the playback device and sacrificing the usability of the playback device. The playback device stores, to its internal memory, identification information of audio data stored on a recording medium such as an optical disc, and specifying information specifying the storage location of the identification information. The playback device sequentially stores the audio data to a remaining area of the memory. The audio data stored in the memory is supplied for playback.

Abstract: A method for adjusting a tilt angle of a light beam emitted by an optical pickup unit of an optical disc drive, the method includes steps of adjusting the tilt angle of the light beam according to test parameters preinstalled in the optical disc drive; detecting focusing error signals, the focusing error signals being generated based on the light beam reflected from an optical disc; generating current parameters based on the focusing error signals; storing the current parameters; adjusting the tilt angle of the light beam according to the current parameters.

Abstract: A signal gain control method and system for use in optical disc drives to prevent undesirable saturation occurrences in circuit operations. The method includes fetching a preset reading front monitor diode signal and a preset gain controlling signal for reading; generating a front monitor diode signal by a front monitor diode signal conversion circuit; calculating a gain controlling signal based on the preset gain controlling signal for reading, the preset reading front monitor diode signal, and the front monitor diode signal by a signal processor; adjusting a gain for detection signals according to the gain controlling signal by a gain adjustment unit; and generating control signals according to the adjusted detection signals by a pre-amp module.

Abstract: A reading device for holographic storage includes a light source, a light-directing component, an optical sensor and a prism. The light-directing component is disposed on the transmission path of the light beam provided by the light source and directs the light beam to get incidence at a holographic storage medium in a reading angle to generate a data beam. The optical sensor is suitable for reading the data beam and reproducing stored data. The prism is disposed between the light source and the holographic storage medium and rotatable about a rotation axis perpendicular to the transmission path of the light beam for fine-adjusting the reading angle. The prism and the light beam satisfy the following formula: ?{square root over (n2?sin2I1)}×sin A?cos A sin I1<1 I1 is the angle of incidence of the light beam, A is the vertex angle between the light incident surface and the light emerging surface and n is the refractive index of the prism.

Abstract: An optical storage system for storing data in an optical medium comprises an initial light source, a first sheet, a light modulator and a second sheet. The initial light source provides an initial light beam. The first sheet comprises a first surface and a second surface, wherein the initial light beam is partially reflected on the first surface to act as a reference beam, and the initial light beam partially passes the first surface, reflected on the second surface to act as a signal beam. The light modulator provides a pattern, wherein the signal beam contacts the light modulator. The second sheet comprises a third surface and a fourth surface, wherein the reference beam is reflected toward the optical medium on the third surface, the signal beam is reflected toward the optical medium on the fourth surface, and the reference beam and the signal beam interfere with each other to store the pattern into the optical medium.

Abstract: Application program interfaces for controlling an external media changer from a computer are provided. The application program interfaces allow for loading and identification of discs in a media changer. The application program interfaces can further allow for control of media changer functions such as locking of media changer elements and playback of disc content for discs in the media changer.

Abstract: There are provided an optical recording method, an optical recording apparatus, a one-chip CPU device, and a computer program. Reference data corresponding to a recording condition of a first recording layer, a physical characteristic value correlated with the recording condition, and a physical characteristic value correlated with a recording condition of a second recording layer are extracted from a data table in a memory, and the recording condition of the extracted reference data is set as a recording condition of a recording medium as an information recording target. When no correlated reference data exists, the closest reference data are extracted from the data table, and a recording pulse condition suitable for recording information on the second recording layer of an optical disk as the information recording target is extracted on the basis of the correlation between the recording condition of the reference data and the physical characteristic value.

Abstract: A method for recording a unique ID to a read-only optical disk adopts the 1-7 PP modulation technique and provides in a plurality of predetermined positions postscript areas each having a predetermined postscript pattern. The postscript pattern takes a form of 3T (pit)-2T (land)-3T (pit) and has a length of 8T (largest code length of a modulated bit string). Modulated bit strings before and after the 3T-2T-3T postscript pattern are formed so that the pit-land-pit postscript pattern complies with the rule of the variable-length modulation even when it is replaced as a whole with a pit-only pattern. Further, the land in the middle will not physically change when irradiated with laser light having a reading-level power, but will be melted with a power higher than the reading-level one.

Abstract: In certain inventive aspects there are provided an optical recording method, an evaluation indicator acquiring method, an optical recording apparatus, and a CPU device, which can save a test time before recording information. An irradiation condition suitable for recording information on a first recording layer is extracted by recording and reproducing test information. The test information is recorded on and reproduced from a second recording layer. The irradiation condition suitable for recording information on the second recording layer is extracted on the basis of the test result for the first recording layer and the test result for the second recording layer. Accordingly, it is possible to save the test time for extracting the irradiation condition of the second recording layer.

Abstract: It is an object to provide an optical information recording medium for land/groove recording, capable of recording at a plurality of linear speeds, wherein deterioration of jitter of the reproduction signal is prevented in recording and reproduction at low linear speeds. To this end, there is provided an optical information recording medium having a land/groove structure and being capable of recording at a plurality of linear speeds, wherein the ratio of the maximum recordable linear speed to the minimum recordable linear speed has a value of 2 to 3, and the ratio of the amount of light reflected from a groove in an unrecorded state to the amount of light reflected from a land in an unrecorded state has a value of at least 1.08 and no more than 1.19.

Abstract: An optical disc with a first recording layer has first data pits that include 14T data pits formed thereon in compliance with DVD-ROM specifications. A first reflective film is formed on the first recording layer, whereby the first reflective film has the relationship of 2.3?Pw/Tf?14 between the 14T pit width and the first reflective film thickness. The disc also includes a second recording layer having a first surface and an opposed second surface, whereupon second data pits are formed on the first surface in compliance with BD-ROM specifications. A second semi-transparent reflective film is formed on the second recording layer, while a transparent layer having opposed third and fourth surfaces is formed over the second reflective film at the third surface, such that the fourth surface allows a laser beam to pass therethrough in reproduction from either the first or second data pits.

Abstract: A method for setting a layer-jump point on a multilayer optical disc in an optical drive for accessing the multilayer optical disc. First, a magnetic-pole cycle value is accumulated. Next, a lag control signal of the optical drive is detected to record the magnetic-pole cycle value as a magnetic-pole basic value. Then, a magnetic-pole offset value is generated according to a phase difference between the lag control signal and an oscillating position of the multilayer optical disc. Finally, a layer-jump-point reference value, according to which the optical drive moves from one layer of the multilayer optical disc to another layer thereof to access data, is set by adding the magnetic-pole basic value to the magnetic-pole offset value.

Abstract: An optical disc apparatus has: an optical head 400 for emitting a light beam onto a predetermined track of an optical disc 300 before tracking control in order to detect reflected light with a photodetector; an arithmetic circuit 130 for generating measurement signals each indicative of a time-varying change of light received on a respective one of a plurality of light receiving areas of the photodetector; an A/D converter circuit 140 for A/D converting each measurement signal; a microcomputer 190 for determining a correction value based on a difference, in terms of high- and low-frequency components, between measurement signals having been A/D converted; and an adder circuit 180 for adding the correction value to a driving value output from a tracking control circuit 170, so that the driving value is corrected.

Abstract: Hybrid optical disc has a DVD layer and a HDDVD layer in a laminating direction. When regional assignments as shown in FIGS. 5A and 5B are applied to these layers, regional information in the DVD layer contains “1” in the bit position corresponding to Code 2 and Code 3, and the HDDVD layer contains “1” in the bit position corresponding to Code p, Code q, and Code r+1 through r+4. Thereby, any one of contents recorded in the two layers can be reproduced in Japan, Greenland, Korea, and Southeast Asia nations.