Abstract: An optical disc recording apparatus 100 comprises a temperature detecting circuit 141 for detecting a temperature of an optical disc 200 and corrects a laser power for discoloration a discoloration layer of the optical disc 200 in accordance with the temperature detected by the temperature detecting circuit 141 in order to cancel a change in the temperature of the optical disc 200. The optical disc recording apparatus 100 can record a high quality visible image on an optical disc without a printer.

Abstract: A PWM circuit converts output data of a calculator to a pulse width modulation signal, and outputs it to a load (speaker) through a buffer amplifier and a low-pass filter. A digital low-pass filter has the same filter characteristic as a low-pass filter. An error calculator calculates the error ?(z) between the input data and the output of the filter, and outputs it to the calculator. The output of the filter becomes a digital signal having substantially the same digitalized waveform as an analog signal applied to the load, and also no distortion contains in the digital signal. Accordingly, the output data ?(z) of the error calculator becomes data corresponding to the distortion of the output signal. In the calculator, the data ?(z) is subtracted from the input data, and the subtraction result is applied to the PWM circuit to reduce the distortion.

Abstract: A PWM circuit converts output data of a calculator to a pulse width modulation signal, and outputs it to a load (speaker) through a buffer amplifier and a low-pass filter. A digital low-pass filter has the same filter characteristic as a low-pass filter. An error calculator calculates the error ?(z) between the input data and the output of the filter, and outputs it to the calculator. The output of the filter becomes a digital signal having substantially the same digitalized waveform as an analog signal applied to the load, and also no distortion contains in the digital signal. Accordingly, the output data ?(z) of the error calculator becomes data corresponding to the distortion of the output signal. In the calculator, the data ?(z) is subtracted from the input data, and the subtraction result is applied to the PWM circuit to reduce the distortion.

Abstract: An optical disk apparatus for forming an image on an optical disk according to dot data which defines density of dots of the image, the optical disk apparatus includes: a framing unit which makes a frame data by grouping a plurality of unit data, wherein when the dot data, the dot data are treated as the unit data; a pit forming unit which sequentially forms pits defined by a bit train signal of the frame data; a discrimination unit which determines whether the section in the frame data corresponding to the dot data is a predetermined value; and a gate unit which, in case the discrimination result by the discrimination unit is affirmative, supplies the bit train signal to the pit forming unit and, in case the discrimination result by the discrimination unit is negative, interrupts supply of the bit train signal to the pit forming unit.

Abstract: A system and method of drawing a visible image on an optical disk are provided. The optical disk is rotated while a optical pickup irradiates a laser beam onto the optical disk to draw the visible image on the optical disk. The rotating state of the optical disk is detected. The optical pickup is fed in a radial direction of the optical disk. An irradiating position of the laser beam is controlled relative to the optical disk by fixing the laser beam in the radial direction of the optical disk during one rotation of the optical disk, and shifting the irradiating position of the laser beam by a first distance in the radial direction each time one rotation of the optical disk is detected. The optical pickup is fed in the radial direction by a second distance the optical disk has rotated a predetermined number of rotations.

Abstract: A position of a speaker is detected two-dimensionally or three-dimensionally, and a sound field is corrected. A sound reproducing apparatus includes a measuring signal generating portion for generating a first measuring signal, a transmission portion for transmitting a second measuring signal as soon as the first measuring signal is generated, sensors disposed in a listening position and for measuring a time difference between a time instant when the second measuring signal was received and a time instant when a measuring sound wave radiated from a to-be-detected speaker in accordance with the first measuring signal was received, and a position calculating portion for calculating a distance, as to each of n sensors, between each of the n sensors and the to-be-detected speaker based on the measured time difference, and calculating the position of the to-be-detected speaker based on distances among the n sensors and the calculated distance.

Abstract: An optical disk apparatus for forming an image on an optical disk according to dot data which defines density of dots of the image, the optical disk apparatus includes: a framing unit which makes a frame data by grouping a plurality of unit data, wherein when the dot data, the dot data are treated as the unit data; a pit forming unit which sequentially forms pits defined by a bit train signal of the frame data; a discrimination unit which determines whether the section in the frame data corresponding to the dot data is a predetermined value; and a gate unit which, in case the discrimination result by the discrimination unit is affirmative, supplies the bit train signal to the pit forming unit and, in case the discrimination result by the discrimination unit is negative, interrupts supply of the bit train signal to the pit forming unit.

Abstract: An optical information-recording medium includes: a substrate; an electronic information-recording layer on the substrate in which digital information is recorded by the light applied from the side of the substrate; a reflection layer on the electronic information-recording layer; a visible information-recording layer on the reflection layer so that a region of the visible information-recording layer lays outside a circumference having a radius not less than half a radius of the substrate; and an over-coating on the visible information-recording layer. Visible information is recorded in the visible information-recording layer with light applied through the over-coating.

Abstract: An optical disc recording apparatus can draw an image by radially vibrating a laser beam under stable focus control. A pickup radiates the laser beam onto the optical disc rotated by a spindle motor. A focus servo controller maintains a constant spot diameter of the laser beam on the optical disc by detecting a return light of the laser beam reflected back from the optical disc. An irradiation position controller operates when the pickup opposes a label face of the optical disc for controlling an irradiation trajectory of the laser beam to vibrate in a radial direction of the optical disc while the laser beam runs along circumferential zones defined on a coloring layer of the label face. A modulating section modulates an intensity of the laser beam for forming dots along the circumferential zones so as to draw the image.

Abstract: An image forming apparatus includes: a spindle motor (130) for rotating an optical disk (200); an optical pick-up (100) for applying laser light to the optical disk which moves in a radial direction of the optical disk; a stepping motor (140) for transporting the optical pick-up in the radial direction by a predetermined distance every time the optical disk is rotated plural times; a tracking actuator for actuating a position of laser light irradiated from the optical pick-up; a servo circuit (138) for controlling the tracking actuator in such a manner that irradiation loci of the laser light is made different from each other every time the optical disk is rotated plural times; and a data converter (160) for defining intensity of the laser light in accordance with gradation of dots to be arrayed and a total rotation time of the optical disk.

Abstract: An image forming apparatus includes: a spindle motor (130) for rotating an optical disk (200); an optical pick-up (100) for applying laser light to the optical disk which moves in a radial direction of the optical disk; a stepping motor (140) for transporting the optical pick-up in the radial direction by a predetermined distance every time the optical disk is rotated plural times; a tracking actuator for actuating a position of laser light irradiated from the optical pick-up; a servo circuit (138) for controlling the tracking actuator in such a manner that irradiation loci of the laser light is made different from each other every time the optical disk is rotated plural times; and a data converter (160) for defining intensity of the laser light in accordance with gradation of dots to be arrayed and a total rotation time of the optical disk.

Abstract: An optical disk apparatus is constructed for writing or reading information by irradiating a laser beam onto an optical disk while rotating the optical disk under a focus control of the laser beam relative to the rotated optical disk. In the optical disk apparatus, an irradiating section is operated to irradiate a laser beam onto the optical disk. A determining section determines a process pattern of the focus control by operating the irradiating section to irradiate the laser beam onto a predetermined area of the optical disk and by monitoring the laser beam reflected back from the predetermined area. A focusing section performs the focus control to regulate a spot diameter of the laser beam based on the determined process pattern during either of the writing or reading of information.

Abstract: In a case where an image of a density that is uniform over a substantially whole area of an optical disc (200) is to be formed, a servo circuit (138) controls the rotation speed of a spindle motor (130) to be constant, and an ALPC circuit (162) controls the current level of a drive signal Li so that the laser power is constant. In this case, a main control section (170) sets the movement distance of an optical pickup (100) to be larger in the inner peripheral side where the line width of the image is larger, and that of the optical pickup (100) to be smaller in the outer peripheral side where the line width is smaller. The main control section (170) sends to a the motor driver (142) instructions for moving the optical pickup (100) by a movement distance which is determined on the basis of the setting.

Abstract: A D class amplifier of the invention generates a carrier signal Pct based on a master clock ?p without jitter, which is supplied to a PWM circuit. Using a digital PLL including a phase comparator, a loop filter and a carrier oscillator, the generated carrier signal Pct is synchronized with a sampling signal SL. This can produce the carrier signal Pct that is not affected by the jitter contained in the sampling signal SL. Because a phase difference between the sampling signal SL and the carrier signal Pct is fedback to through a feedback circuit, jitter, which can be produced by a slight difference between the sampling signal SL and the master clock ?p can be eliminated.

Abstract: The invention is directed to a class D amplifier. According to the class D amplifier, sound data applied to an input terminal is supplied through a compensation circuit to a PWM circuit, from which a PWM signal is output. The PWM signal is converted to an analog signal through a first low pass filter, which is delivered to a speaker. On the other hand, the sound data is delayed by a delay circuit, and is converted to an analog signal by a digital to analog converter. The higher frequency components of the data are removed by a second low pass filter, and the rest of the data is furnished to a differential amplifier. The differential amplifier amplifies a difference between an output of the first low pass filter and an output of the second low pass filter, which is then supplied to an analog to digital converter. The analog to digital converter converts an output from the differential amplifier to digital data, which is then supplied to the compensation circuit.

Abstract: A system and method of drawing a visible image on an optical disk are provided. The optical disk is rotated while a optical pickup irradiates a laser beam onto the optical disk to draw the visible image on the optical disk. The rotating state of the optical disk is detected. The optical pickup is fed in a radial direction of the optical disk. An irradiating position of the laser beam is controlled relative to the optical disk by fixing the laser beam in the radial direction of the optical disk during one rotation of the optical disk, and shifting the irradiating position of the laser beam by a first distance in the radial direction each time one rotation of the optical disk is detected. The optical pickup is fed in the radial direction by a second distance the optical disk has rotated a predetermined number of rotations.

Abstract: An optical disk apparatus records information by irradiating a laser beam from a pickup onto an optical disk. A scanning section scans the laser beam relative to the optical disk. A recording control section controls the scanning section to effect recording of information. A drawing control section is provided for controlling the pickup and the scanning section to effect drawing of a visible image on the optical disk according to image information, such that the laser beam is changed between a first intensity incapable of acting on the optical disk and a second intensity capable of acting on the optical disk. A servo section periodically detects the laser beam reflected back from the optical disk when the laser beam has the first intensity, and servo-controls the irradiating of the laser beam during the drawing of the visible image based on the detection of the laser beam.

Abstract: The invention provides a pulse width modulation amplifier that includes a correction circuit, an envelope detector, a level detector, a PWM carrier generator, an interpolation arithmetic circuit, and a PWM circuit. The envelope detector detects an envelope of digital data to be input. The correction circuit performs distortion correction, frequency characteristic correction, and ?? correction, for the input digital data. The level detector detects levels of the digital data supplied by the envelope detector. The PWM carrier generator gates a carrier signal having a frequency corresponding to the output of the level detector. The interpolation arithmetic circuit generates interpolation data synchronous with the carrier signal from the digital data. The PWM circuit converts the interpolation data into a pulse width modulation signal based on the carrier signal.

Abstract: An optical disk apparatus is constructed for writing or reading information by irradiating a laser beam onto an optical disk while rotating the optical disk under a focus control of the laser beam relative to the rotated optical disk. In the optical disk apparatus, an irradiating section is operated to irradiate a laser beam onto the optical disk. A determining section determines a process pattern of the focus control by operating the irradiating section to irradiate the laser beam onto a predetermined area of the optical disk and by monitoring the laser beam reflected back from the predetermined area. A focusing section performs the focus control to regulate a spot diameter of the laser beam based on the determined process pattern during either of the writing or reading of information.

Abstract: A PLL circuit (24) reproduces a clock signal from a reproduction EFM signal of an optical disk (10). A phase error signal (pco) of the PLL circuit (24) is converted into an absolute value by an absolute value circuit (38), and is averaged for each subcode frame period by an accumulator (40). The recording beam power of a laser beam is determined on the basis of an output of the accumulator (40). A pulse-length discrimination circuit (26) discriminates the pulse length of the reproduction EFM signal. A specific-pulse-length phase-error-signal extracting circuit (42) extracts the phase error signal (pco) of a specific pulse length. The extracted phase error signals (pco) are averaged for the respective subcode frame periods by a accumulator (44). The time base of the corresponding pulse length of the recording EFM signal is corrected on the basis of the output of the accumulator (44).