Abstract: There is provided an optical disk apparatus having a function capable of preventing a focusing error detecting function from operating during a seeking operation with a simple circuit configuration. If crosstalk level determining means 43 determines that the signal level of a crosstalk measured in crosstalk level measuring means 42 is equal to or greater than a threshold value, focus gain reducing means 44 reduces the gain of an amplifier 45, that is, the focus gain in accordance with the signal level of the crosstalk during a seeking operation. It is therefore possible to prevent a focusing error detecting function from operating during a seeking operation and thereby to prevent a seeking error, which can eliminate the need for an operational circuit to prevent a focusing error with a simple circuit configuration, resulting also in cost reduction.

Abstract: In performing the balance regulation of focus error signal, the balance of the focus error signal is changed in a predetermined range. Then, the level of the RF signal is measured while continuously changing the balance of the focus error signal and the balance of the focus error signal is changed in a predetermined range when the RF signal level becomes maximum. Then, jitter is measured while changing the focus error signal level. An intermediate balance regulation value between the balance regulation value of the focus error signal when the RF signal level is maximum and the balance regulation value of the focus error signal when the jitter is minimum is calculated. The focus balance regulation is performed by the calculated intermediate balance regulation value.

Abstract: The present invention provides an optical disk recording and reproducing apparatus having a circuit configuration whereby it is possible to prevent tracking drive signals from being offset even when the temperature of a tracking actuator drive circuit is increased.

Abstract: A disk reproducing apparatus for reproducing a digital audio signal recorded on a DVD or CD has a PLL portion for outputting a synchronizing signal in synchronism with the digital audio signal. When the CD is reproduced at double speed or higher, the PLL portion increases again while seeking tracks, and restores the gain if a predetermined time has passed after the end of seek.

Abstract: A plurality of liquid crystal modules is vertically and horizontally arranged, each of which is supplied light by a light source via optical fibers. A screen can be wound up at a cabinet. An image from each of the plurality of liquid crystal modules does not interfere one another because a light shielding board is installed.

Abstract: A code reading pattern and an image pickup apparatus are provided for reading a symbol representing significant information, the symbol encoded by the pattern. The code reading pattern is formed by repeated markings of constant pitch on the surface of an object. The markings define area having at least one boundary, the at least one boundary defining an outline of the symbol. The apparatus includes a lighting system for illuminating the code reading pattern with parallel light, an imaging system for imaging light reflected from the pattern, a spatial frequency filtering system, located at the near back focal plane of the imaging system, for blocking regular reflected light and for transmiting diffracted light to project an image of the symbol, and a receiver for receiving the image.

Abstract: A gradation record printer in which an amount of energy applied to a thermal head is controlled in response to a gradation level of an input image signal to print an image on a printing medium with gradations. The printer comprises a gradation density detecting unit for storing data of standard density patterns with respect to address values corresponding to gradation levels and for outputting a coincidence signal when data supplied from an outside of the gradation density detecting unit substantially coincides with the data of standard density patterns. A gradation test print circuit is used to apply data of different amounts of printing energy to the thermal head sequentially to make a gradation test print on the printing medium. A density detecting sensor detects densities of the gradation test print and applies a detection output from the density detecting sensor to the gradation density detecting unit.