Abstract: The present invention provides an optical disk apparatus adapted to irradiate a predetermined track reliably with a laser beam in a seeking operation independently of the individual differences between tracking actuators and therefore optical pickups. A signal adjusting circuit 57 of a servo driver circuit 5 consists of a first amplifier 571 adapted to receive a period error signal that indicates the difference between a target period and a detection period and then output a reference drive signal having a prescribed amplitude in accordance with the difference, and a second amplifier 572 adapted to adjust the reference drive signal by being multiplied by the inverse number of a servo gain G which is different for each optical pickup 1. This allows the reference drive signal adjusted in accordance with the characteristics of a tracking actuator 12 of the optical pickup 1 to be input to a tracking drive signal generating circuit 58.

Abstract: An optical pickup actuator circuit includes: a lens holder 2 supported so as to be slidable along a support shaft and rotatable around the support shaft and for holding an objective lens 8 so that the objective lens 8 forms an image of a light beam on a desired track on an information recording surface of an optical disk; a focusing coil 7 attached to the lens holder 2; and a focusing magnet fixedly disposed so as to be opposite to the focusing coil 7; wherein two diodes D1 and D2 are parallel-connected in a forward direction between an input end 7a of the focusing coil 7 and the ground so that an input voltage not lower than a predetermined voltage is led to the ground by the two diodes D1 and D2.

Abstract: An optical disc apparatus includes a servo gain adjuster, which includes a disturbance signal supplying unit that generates plural disturbance signals of different frequencies and supplies them in sequence to a servo loop, a gain characteristic measuring unit that measures a deviation of a servo gain characteristic of the servo loop based on each disturbance signal passed through the servo loop, an average gain characteristic calculating unit that calculates the average of deviations of plural servo gain characteristics measured by the gain characteristic measuring unit in response to the plural disturbance signals supplied from the disturbance signal supplying unit, and a gain adjustment amount determining unit that determines an amount of adjustment to the servo gain of the servo loop based on the average of the deviations of the servo gain characteristics that is calculated by the average gain characteristic calculating unit.

Abstract: An optical disk reproducing device accurately measuring a defect signal and having increased accuracy of an automatic adjustment includes an objective lens and light receiving element unit reading a signal from an optical disk, a CPU for making a determination, according to whether values of three signals fall out of a prescribed range, as to whether the three signals are defect signals or not, a tracking control unit for generating a signal representing an estimated position of the objective lens when the signals are defect signals, and generating a signal representing the same content as that of the signals read by the objective lens and light receiving element unit when the signals are not defect signals, and an actuator for changing a position of the objective lens according to a content of the signal generated by the tracking control unit.

Abstract: The present invention provides an optical disk apparatus adapted to irradiate a predetermined track reliably with a laser beam in a seeking operation independently of the individual differences between tracking actuators and therefore optical pickups. A signal adjusting circuit 57 of a servo driver circuit 5 consists of a first amplifier 571 adapted to receive a period error signal that indicates the difference between a target period and a detection period and then output a reference drive signal having a prescribed amplitude in accordance with the difference, and a second amplifier 572 adapted to adjust the reference drive signal by being multiplied by the inverse number of a servo gain G which is different for each optical pickup 1. This allows the reference drive signal adjusted in accordance with the characteristics of a tracking actuator 12 of the optical pickup 1 to be input to a tracking drive signal generating circuit 58.

Abstract: An optical pickup actuator circuit includes: a lens holder 2 supported so as to be slidable along a support shaft and rotatable around the support shaft and for holding an objective lens 8 so that the objective lens 8 forms an image of a light beam on a desired track on an information recording surface of an optical disk; a focusing coil 7 attached to the lens holder 2; and a focusing magnet fixedly disposed so as to be opposite to the focusing coil 7; wherein two diodes D1 and D2 are parallel-connected in a forward direction between an input end 7a of the focusing coil 7 and the ground so that an input voltage not lower than a predetermined voltage is led to the ground by the two diodes D1 and D2.

Abstract: A fire-lighting device includes a jetting nozzle for jetting fuel gas, a gas passage for fuel gas to be burned extending from a fuel tank to the jetting nozzle, and a sintered filter made of sintered powder inserted in the gas passage upstream of a small-diameter portion. Provision of the sintered filter prevents obstruction of fuel supply by foreign matter clogging the gas passage at a nozzle plate of the jetting nozzle.

Abstract: A portable heater is made up of a cylindrical outer case 2 with at least one end thereof opened; a container to be heated 6 fixedly housed in the outer case 2 with a gap between the container and said outer case for the updraft of a combustion gas, the container being made of a cylindrical heat resisting container body 6c having a top 6b provided with an opening tab 6a; a burner 3 which is equipped with an ignition means 8, and is fixedly housed in the outer case 2 at a lower inside thereof so as to heat the container 6; and a fuel tank 4 fixed in a lower inside of the outer case 2 for supplying fuel to the burner 3. The container 6 holds contents to be heated when the heater is in use, and the outer case 2 has vent holes for supplying air from the outside to the burner 3. Thereby, contents of the container can be heated at any desired time and place without drawing the contents of the container by opening the top of the container.