Abstract: Blue color forming sub-layer (205), green color forming sub-layer (206) and red color forming sub-layer (207) which start to form colors upon application of different amounts of energy are superposed on the image surface of optical disc (D). The color forming sub-layer which requires the smallest amount of energy to form color is first illuminated with laser of the power required to realize color formation from that sub-layer; subsequently, this sub-layer is illuminated with ultraviolet radiation to fix the color it has formed. Then, the next color forming sub-layer is illuminated with laser of the required power and after fixing the color it has formed, the last color forming sub-layer is illuminated with the required laser to form color.

Abstract: A time period control unit controls a time length “TU” of each of unit terms “U” in a variable manner. A pulse-width modulating unit is arranged by a holding unit, a counting unit, and a waveform generating unit. The holding unit holds thereinto a plurality of data “XD” every unit term “U”, which are sequentially supplied, as data “XE.” The counting unit changes a count value “X” during each of the unit terms “U.” The waveform generating unit generates such a pulse-width modulating signal “S” that pulses “P” have been arranged every unit term “U”, while time points when a large/small relationship between the count value “C” and a numeral value of the data “XE” held by the holding unit is inverted are defined as edge portions of the pulses.

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: A signal generating apparatus includes: a data generator which generates a data series in which first, second, third and fourth data are arranged at a sampling period; a first signal generator which generates a first pulse-width modulation signal in which a pulse is arranged in a pulse period longer than the sampling period, time points of front and rear edges of the pulse being set in response to the first and second data; and a second signal generator which generates a second pulse-width modulation signal in which a pulse is arranged between the adjacent pulses of the first pulse-width modulation signal, time points of front and rear edges of the pulse of the second pulse-width modulation signal been set in response to the third and fourth data, respectively.

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: To provide an optical information recording medium on which visual information can be recorded on a label face by using a laser apparatus for recording and reading electronic information by irradiation with a low output laser without exerting e.g. thermal influence over electronic information recorded on the medium. The present invention provides an optical information recording medium 100 having such a structure that on a substrate 101, an electronic information recording layer 102, a reflective layer 103 formed in contact with the opposite side of the electronic information recording layer 102 from a side where a laser beam 107 enters, a protective layer 104, a visual information recording layer 105 and an overcoat layer 106 constituting an outermost layer are laminated in this order, wherein the surface roughness of the outermost layer on the label face side is at most ½ of the wavelength (?) of a laser beam 108.

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 visible image forming method is performed for forming a visible image on an optical disk by an optical disk recording apparatus, which is designed for applying a laser beam onto an optical disk according to first recording data of a predetermined format to form pits having lengths specified by the first recording data. First, a generating step is performed for generating second recording data by embedding image formation data of a visible image in a part of a predetermined format which is the same as predetermined for the first recording data. Second, an extracting step is performed for extracting the image formation data of the visible image from the second recording data of the predetermined format. Then, a forming step is performed for forming pits in the optical disk according to the extracted image formation data so as to form the visible image on the optical disk.

Abstract: In an apparatus for recording a broadcast program on an optical disk, a broadcast reception section receives a broadcast signal containing various programs broadcasted from a broadcast station. A recording setup section specifies a program to be recorded on an optical disk among the various programs contained in the received broadcast signal. An information acquisition section acquires attribute information associative of content of the specified program from an electronic program guide of various programs.

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: 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 controlling unit 130 of an optical disc recording apparatus judges a failure of a focus servo in accordance with an output signal of a servo circuit 107. When a failure of the focus servo is detected, a laser light irradiating position at the time of the failure is obtained as a standard position and a laser power controlling unit 140 is controlled to pause a control of the laser power based on data to be recorded. Thereafter, the laser power controlling unit 140 and a position of an optical pickup 103 are controlled to restart the control of the laser power based on the data to be recorded from the standard position as a starting position.

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: A digital input class-D amplifier includes a decoder which outputs a plurality of lines of time-series digital signals having a density of 1 or 0 conforming to an input digital signal, an error integrator which integrates a difference between a drive waveform to be applied to a load and a sum of the plurality of lines of time-series digital signals output from the decoder, and a modulation circuit which generates a pulse modulated with a pulse width or a pulse density based on a result of integration performed by the error integrator. The load is driven in accordance with the pulse generated by the modulation circuit.

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 ??-type AD converter includes a subtractor which receives an analogue input signal and a feedback signal and which outputs a signal pertaining to a difference between the signals, an integrator which integrates a signal output from the subtractor, a comparator which binarizes a signal output from the integrator by comparing with a predetermined threshold value, a counter which measures respective pulse widths of a signal output from the comparator, and a PWM circuit which outputs a pulse signal of a predetermined period having a duty cycle responsive to a count value output from the counter and which feeds back the pulse signal as the feedback signal to the subtractor. The counter measures the respective pulse widths in each PWM frame period in synchronism with the PWM circuit, and the PWM circuit feeds back to the subtractor a pulse signal whose duty cycle is set in accordance with a value of the measured pulse width in a next PWM frame.

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: Laser information is prepared which indicates the irradiation interval and intensity level to be irradiated on an optical disc in advance. Then, when image drawing is indicated together with the indication of the forming spacing for pits, a laser is controlled so as to achieve the irradiation interval and intensity level indicated by the laser information that corresponds to the indicated formation spacing to fabricate pits in the optical disc.

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.