Abstract: Test writing is executed while skipping areas where deviations are present on an optical disk to thereby improve accuracy and reliability of an optimum recording condition to be derived. A deviation detecting unit detects the deviations of a guide groove on the optical disk on the basis of a fluctuation amount of a focus error signal or a tracking error signal, and registers information of the detected deviations onto a memory. A test writing processing unit refers to the memory, and records and reproduces a test signal while skipping the areas where the deviations are detected.

Abstract: Within an optical disk recording/reproducing apparatus, equipped with a test writing method during the recording operation, for improving accuracy on calculating the most-suitable power and recording quality, thereby recording data through irradiation of a laser beam of a predetermined power onto a optical disk, defining test writing areas on an inner periphery side and an outer periphery side and an area recordable with data between those inner periphery side and outer periphery side, or reproducing data recorded thereon from a reflection light thereupon, wherein a controller circuit 9 executes a test writing process, with selecting a test writing area on a periphery side being large in a ratio of difference, upon basis of ratios of the differences between powers on an inner periphery and an outer periphery of said disk, which are set up at present, and control data on the inner periphery and the outer periphery, which are recorded on said optical disk loaded therein, when executing the test writing process

Abstract: A laser driver drives a laser diode by producing a write strategy, that is, a recording waveform from a recording clock and a modulated signal. In one embodiment, a laser driver produces the waveform of a driving signal, which is used to drive a laser diode, using a record data signal that represents record data to be recorded on a recording medium. The laser driver comprises an internal clock production circuit that produces an internal clock synchronous with the record data signal, and a strobe circuit that strobes the record data signal according to the internal clock.

Abstract: Disclosed is a method of reproducing optical information by applying laser light to the medium while rotating a recording medium having concentric information tracks or a spiral information track so that the linear velocity of the medium is constant, and thereby reproducing the information recorded on the recording medium by the reflected light. In this method, in moving a reproduction radial position to a second radial position different from the current position, a laser power is changed to second laser power, which is different from current laser power, and then the light spot is moved to the second radial position. This method can prevent degradation of a medium in reproduction light resistance caused by substantially high power reproduction, and erasing or destruction of already recorded data that may be caused, in high-speed recording of a rewritable-type or write-once-type optical disc, when the linear velocity at the time of reproduction becomes slow, e.g.

Abstract: In the present invention, the processing sequence of a microprocessor for restructuring the recording parameters when changing the recording system from the CAV system to a CLV system is as follows: (1) interrupt the recording process; (2) calculate linear velocity at a broken point where recording linear velocity becomes constant; (3) calculate a third recording parameter in the linear velocity by a linear interpolation based on first and second recording parameters which are corrected by test writing, replacing all the recording parameters for an outer circumference side from a radius position where the linear velocity becomes Cx, with the third recording parameter; and (4) restart recording with the third recording parameter as a recording condition.

Abstract: The present invention determines accurately whether trial write processing is necessary or not and eliminates unnecessary trial write processing to prevent the degradation of the data transfer rate. A control circuit, if an error is detected during reproduction of recorded data, compares a top value Vtop of an envelope of a reproduced signal with a predefined threshold value Vth for defect detection. As a result of comparison, if Vtop>Vth, trial write processing is performed; and if Vtop<Vth, trial write processing is not performed. The level of the threshold value Vth is set between time-mean level at an envelope's top value and that at an envelope's bottom value.

Abstract: An optical disc reproducing apparatus and an optical disc recording apparatus for reproducing an optical disc. The apparatus includes an optical pickup unit for irradiating a laser beam to the optical disc, an optical pickup drive unit for moving the optical pickup in the radial direction of the optical disc, and a motor unit for rotating the optical disc. When a tracking jump command is issued, the optical pickup drive unit moves the optical pickup unit in the radial direction of the optical disc at the timing in accordance with the rotation speed of the optical disc after the laser beam irradiated to the optical disc has passed the address information recording portion indicating the address of the optical disc.

Abstract: In the sample-and-hold circuit for laser power detection signal and servo signal, the sample-and-hold operation timing is controlled to set by monitoring the output from the sample-and-hold circuit. In the invention of this application, the sample-and-hold timing is changed to be larger or smaller than the estimated timing, and reference is made to the result of the monitoring, thus determining the optimum timing. The sample-and-hold timing is controlled to fix to this optimum value.

Abstract: An information recording medium includes data concerning a maximum linear velocity (V1max) and a minimum linear velocity (V1min) at a first location on the medium and a maximum linear velocity (V2max) and a minimum linear velocity (V2min) at a second location on the medium, are recorded at a predetermined location on said medium, and at the first and second locations both of which are located at different locations on the medium, performing selectively CLV/CAV (Constant Linear Velocity/Constant Angular Velocity) control or alternatively a CLV/CAV-hybrid control.

Abstract: A laser driver drives a laser diode by producing a write strategy, that is, a recording waveform from a recording clock and a modulated signal. In one embodiment, a laser driver produces the waveform of a driving signal, which is used to drive a laser diode, using a record data signal that represents record data to be recorded on a recording medium. The laser driver comprises an internal clock production circuit that produces an internal clock synchronous with the record data signal, and a strobe circuit that strobes the record data signal according to the internal clock.

Abstract: Recording parameters are decided so that the time control information on at least the front edge and the rear edge of a parameter forming a mark of twice size or above of the laser spot diameter focused on the recording medium is substantially proportional to the recording linear velocity. The mark is recorded and reproduced at a predetermined linear velocity to obtain an electric signal waveform having a time width Tm. A parameter is decided so as to control the laser pulse for recording information so that a voltage value change amount at two points at a distance Ts (Ts<Tm/2) in the time axis direction before and after the time position Tm/2 from the front edge of the waveform is substantially constant for the recording linear velocity change. Identification information indicating the parameter is described on the recording medium.

Abstract: If adequate setup time or hold time cannot be provided between a recording clock signal and modulated signal during the use of a laser control integrated circuit for generating a recording strategy from the recording clock signal and modulated signal to drive a laser diode, the disk recording information becomes erroneous. To solve this problem, the present invention provides the laser control integrated circuit input stage for the recording clock signal and modulated signal with variable delay devices that can vary the phases of these signals. The variable delay devices control the delay amounts of the variable delay devices in accordance with disk recording information error and optimize the phase relationship between the recording clock signal and modulated signal.

Abstract: A filler for separating an optical isomer comprising a surface-hydrophobic filler component and an optically active lipophilic crown compound carried on the filler component by adsorption. The filler may be charged in a column to carry out separation of a sample such as amino acid or the like in the form of an aqueous solution.