Abstract: According to a disclosed embodiment, an endpointer determines the background energy of a first portion of a speech signal, and a cepstral computing module extracts one or more features of the first portion. The endpointer calculates an average distance of the first portion based on the features. Subsequently, an energy computing module measures the energy of a second portion of the speech signal, and the cepstral computing module extracts one or more features of the second portion. Based on the features of the second portion, the endpointer calculates a distance of the second portion. Thereafter, the endpointer contrasts the energy of the second portion with the background energy of the first portion, and compares the distance of the second portion with the distance of the first portion. The second portion of the speech signal is classified by the endpointer as speech or non-speech based on the contrast and the comparison.

Abstract: The invention is directed to the provision of a liquid crystal optical element, for correcting wavefront aberrations (principally, coma aberration and spherical aberration), that can be mounted separately from an objective lens, and an optical apparatus using such a liquid crystal optical element. The liquid crystal optical element according to the invention includes a first transparent substrate, a second transparent substrate, a liquid crystal sealed between the first and second transparent substrates, and an electrode pattern as a region for advancing or delaying the phase of a light beam and thereby correcting wavefront aberration, wherein the region is formed smaller than the field of view of the objective lens so that the region substantially stays within the field of view of the objective lens regardless of the tracking motion of tracking means.

Abstract: Provided are an optical pickup device, which is capable of detecting and correcting spherical aberration while suppressing an increase in the number of construction elements and without increasing outer dimensions of a pickup device main body, and a recording and/or reproducing device having the optical pickup device built therein. A lens is designed such that when the thickness of a disk protective layer is greater than an optimum value, returning light (reflection light) from a disk is condensed on a sensor. The sensor is arranged at a condensing point and has a shape with which around 50% of the returning light is received when the thickness of the protective layer assumes the optimum value. With this construction, the quantity of light received by the sensor is increased when the thickness of the protective layer is greater than the optimum value, and is conversely reduced when the thickness of the protective layer is smaller than the optimum value.

Abstract: The present invention enhances the usability of a write-once recording medium having a plurality of recording layers. The write-once recording medium has a plurality of recording layers each including a regular recording reproduction area, an alternate area, a first alternate-address management information area and a second alternate-address management information area (a TDMA). In addition, written unwritten state indication information (a space bitmap) is recorded therein. Typically, the written unwritten state indication information is recorded in the second alternate-address management information area. By additionally recording alternate-address management information related to an alternate-address process in the second alternate-address management information area, the second alternate-address management information area can be used as an area for implementing renewal of the alternate-address management information.

Abstract: A recording medium has a first area in which data encoded with a first error correction code is recorded and a second area in which data encoded with the first error correction code and data decodable with a second error correction code that is different from the first error correction code are mixedly recorded. Data that causes the cumulated value of a DC component per unit period of data reproduced from the second area to deviate is recorded in the second area.

Abstract: An optical head device includes a light source for emitting light; a collection optical system for collecting the light emitted by the light source to an information memory medium including tracks having prescribed grooves; a light detector having a plurality of detection areas for receiving the light reflected by the information memory medium and outputting a signal in accordance with a light amount of the light received; a tracking error signal generator for receiving the signals output from the light detector and generating a tracking error signal based on the signals; and a light division element for dividing a reflected light reflected by the information memory medium.

Abstract: In a slew rate limiter, a slew rate is limited so as not to pass a signal varying more abruptly than a wobble signal included in a difference signal generated by a differential amplifier, and this limited slew rate is used to process the difference signal to be outputted. That is, the slew rate limiter removes a signal varying more abruptly than a wobble signal included in a difference signal DIFO, and then outputs only the wobble signal. A DAC generates an offset voltage. An adder is used to add this offset voltage to the wobble signal from the slew rate limiter. The signal obtained by this addition as a slice level is compared by a comparator with the difference signal, thereby reproducing an LPP signal.

Abstract: The present invention provides a method and an apparatus for discriminating the type of an optical recording medium and the number of recording layers in the medium. The apparatus includes a first electrode and a second electrode placed in the vicinity of a light transmission layer of the recording medium, an alternating current signal generation circuit for applying an alternating current A to the first electrode, a detection circuit for detecting the level of an alternating current B appearing at the second electrode, and a control circuit for controlling the operations of the alternating current signal generation circuit and the detection circuit, and a table provided in the control circuit.

Abstract: A recording data string is composed of a plurality of synchronous frames each of which has synchronous data and coding data. Data items in the coding data contributed to creation of the same column of the error correction code are arranged at regular intervals of E in the recording data string. A data segment length L is obtained by adding an additional synchronous frame to the recording data string. Wherein, a physical segment length A satisfies the equation L=mA, m is a natural number. And A is set indivisible by E.

Abstract: A system for copy protection of record carriers for digital data is described according to which at least one predetermined repetitive bit pattern which encodes into channel bits having an accumulated digital sum value that exceeds a first predetermined limit and that is below a second predetermined limit is determined and recorded onto said record carrier by a mastering process so that said accumulated digital sum value which exceeds said first predetermined limit and is below said second predetermined limit is achieved in said at least one replaced and/or inserted part.

Abstract: A method is provided for recording data in a write-once type optical recording medium which can record data by forming a recording mark having a desired length and reduce jitter of a reproduced signal. The method comprises determining a pulse train pattern so that a level of a pulse is switched from the level corresponding to the level of the recording power Pw to the level corresponding to the level of the bottom power Pb in accordance with the length of a blank region to be formed immediately after formation of a first recording mark and the length of a second recording mark formed subsequent to the formation of the first recording mark.

Abstract: An optical scanning device (1) is for scanning two information layers (2, 2?) with two radiation beams (4) in two operating modes. It comprises a radiation source (7) for emitting the two radiation beams, an objective lens system (8) for converging the two beams on the positions of the two information layers, and a phase structure (24) having an optical axis (19) and including a central part (P1) and at least one marginal part (P2) for forming a non-periodic stepped profile in the radial direction. One (P2) of said central and marginal parts (P1, P2) includes at least two segments (AS2,1, AS2,2) having two different step heights (h2,1, h2,2), respectively, for introducing in said first operating mode two wavefront modifications W2,1,1? and W2,2,1?, respectively, and in said second operating mode two wavefront modifications W2,1,2? and W2,2,2?, respectively, where the difference (w2,1,2+?W2,2,2)?(?W2,1,1+?W2,2,1?) is asymmetric.

Abstract: An optical system has an expander lens and an objective lens. The following formula is satisfied: W1CM>W2CM, where W1CM is a coma aberration (?rms) of a converged light spot when an off-axial light flux of a wavelength ? (nm) emitted so as to converge at a distance position from the optical axis comes into the objective lens, and W2CM is a coma aberration (?rms) of a converged spot when an off-axial light flux of the wavelength ? (nm) emitted so as to converge at the distant position distant comes through the expander lens into the objective lens on a condition that the optical axis of the expander lens is arranged so as to conform with the optical axis of the objective lens.

Abstract: A laser power selecting method includes the steps of recording an asymmetry measuring recording pattern in an optical disk trial-writing area while a laser power is being changed, reproducing a signal from the trial-writing area to calculate an asymmetry value from the waveform of the reproduced signal, determining the change rate of asymmetry from the relation between a laser power when the recording pattern is recorded and the calculated asymmetry value, and setting a laser power, at which the determined change rate of an asymmetry value is maximum, as a recording power used when recording on an optical disk.

Abstract: A disc recording device has a rule based extent allocation strategy. Real-time information like audio is to be reproduced continuously via a rendering system having predefined properties: a buffer, a minimal read-out speed Rdisc, and a maximal seek time Tseek. The information is arranged in files that have a maximal data rate Rfile, and a maximal size of header information Sheaders that precedes and/or follows the real-time information in the file. The information of the files is recorded in contiguous parts of the track at least having the size of Sextent. The device has an allocation unit (35) for determining a minimal size of an extent Sextent that is a continuous recording unit at least taking into account the properties Rdisc, Tseek, Rfile and Sheaders, in particular according to Sextent=((Tseek+Sheaders/Rdisc)*Rfile*Rdisc)/(Rdisc?Rfile).

Abstract: An optical pick-up includes a lens holder and a lens holder supporting portion. The lens holder has a focusing coil, a tracking coil, and a pair of nickel plates arranged to sandwich the focusing coil from the top and the bottom. The lens holder supporting portion includes a pair of permanent magnets having their magnetic poles of the same polarity opposite to each other and sandwiching the lens holder as seen in two dimensions. A sidewall of a slide hole is pressed against a slide shaft. Thus, a disk drive which can suppress a jerky motion of the lens holder when it moves along the slide shaft with a simple mechanism is provided.

Abstract: An information recording medium for recording main information and auxiliary information is provided. The auxiliary information is recorded on the information recording medium in a manner that edge positions of the pits or the recording marks indicating the main information are shifted either in a phase advancing direction or in a phase delaying direction along the track direction. A predetermined frequency is used to determine whether the edge position is shifted in the phase advancing direction or in the phase delaying direction in order to record the auxiliary information. The predetermined frequency is substantially consistently lower than ½ of a reference frequency of a recording clock for creating the pits or the recording marks and is higher than a response frequency of a PLL for generating a reproduction clock for reproducing the main information.

Abstract: A system and method for adjusting optical drives. Rotating disc datum, and leader pin datum, must be adjusted to a specific position during a packaging process. An autocollimator according to the present invention senses tilt and sway of the rotating disc, outputting a first bright spot through a switch box to a monitor. In addition, an optimum tilt angle of the optical pickup head is obtained by a reader through calculation by a host, outputting a second bright spot through the switch box to the monitor. Therefore, the first bright is coincided with the second bright spot by a adjustment mechanism and according to picture switch by the switch box, reading optimum tilt angle adjustment. Furthermore, individual tilt angle of each optical pickup head is calculated by a host for satisfying adjustment of different tilt angles with different optical paths in reading CD and DVD discs.

Abstract: An information recording medium 101 includes: a transparent substrate 109 having a first surface A and a second surface B opposite to the first surface A; reflectance reduction means 110 provided on the first surface A of the transparent substrate 109; and an information recording layer 120 provided on the second surface B of the transparent substrate 109.

Abstract: A method is described for determining a set of recording pulse series parameters for recording information on an optical record carrier. First a series of test patterns is written on the record carrier with a values of the parameters. On reading the test patterns, the jitter values of each read signal is determined. The optimum values of the parameters are derived from a linear dependence between the set of recording pulse series parameters and the relative jitter values. The invention relates also to a device arranged to perform the method. The invention further relates to an optical record carrier comprising the optimum recording power as determined by the method according to the invention.