Abstract: A scanning optical device that includes a light source for emitting a light flux; a polygon mirror including a plurality of reflecting surfaces for deflecting the light flux to form a scanning beam spot on an image surface; a polygon mirror cover that covers the polygon mirror; and an optical sensor. The polygon mirror is provided with a mark on the top surface thereof that is eccentric from a rotation axis of the polygon mirror. Also, the polygon mirror cover includes a cylindrical rib formed on an inner surface of the top wall projecting toward the polygon mirror in a space between the top wall and the polygon mirror. The optical sensor is provided for detecting the mark and projects toward the polygon mirror from the inner surface of the top wall, through the cylindrical rib, such that the optical sensor forms a part of the cylindrical rib.

Abstract: A multi-beam scanning optical device uses optical fibers to transmit the laser fluxes from the semiconductor lasers. The optical fibers are arranged such that point light sources formed at respective exit ends of the optical fibers are linearly aligned. The exit light fluxes from the optical fibers are deflected by a polygon mirror and converged on an image surface to form a line of beam spots, which forms plurality of scanning lines per scan.In order to adjust the angle of the line of beam spots, the exit end portions of the optical fibers is fixed to a fiber alignment block such that the exit end surfaces of said optical fiber are linearly aligned on an alignment line. Further, the fiber alignment block is fixed to a cylindrical member which is rotatably supported by a supporting member. Accordingly, the angle of the line of beam spots can be easily adjusted by rotating the cylindrical member.

Abstract: A scanning optical device includes a light source, a polygon mirror having a plurality of reflecting surfaces for deflecting a light flux emitted from the light source to form a scanning beam spot on an image surface, an identifying device that identifies which reflecting surface is currently scanning the light flux, a memory that stores data corresponding to shape errors of the reflecting surfaces, a correcting member that corrects a position of the beam spot, and a controller that controls the correcting member in accordance with an output of the identifying device and with data read from the memory. The correcting member is controlled to compensate for deviations of the beam spot due to tilt errors of the reflecting surfaces and may also be controlled to compensate for deviations of the beam spot due to an unevenness of the movement of the image surface.

Abstract: A synchronizing signal generating circuit for an optical scanning device. The synchronizing signal gernerating circuit including a photodiode, a high-pass filter circuit, and a signal processing circuit. The high-pass filter circuit is the load for the photodiode and is comprised of an inductance and a resistance arranged in parallel. The high-pass filter circuit is configured to have a cutoff frequency that is marginally below the frequency of a synchronizing signal. The signal processing circuit is connected to the connection point of the photodiode and the high-pass filter circuit and receives a detection signal. The signal processing circuit amplifies the detection signal, cuts the DC component, and compares the resulting signal to a reference voltage to produce the synchronizing signal.

Abstract: A scanning optical device that includes a light source that emits a light flux; a polygon mirror for deflecting the light flux; a scanning lens for converging the light flux deflected by the polygon mirror to form a beam spot on an image surface; a dynamic prism that is rotatably disposed between the light source and the polygon mirror to affect the direction of the light flux; a driving mechanism for rotating the dynamic prism to change the deviation angle of the dynamic prism; and a controller for controlling the driving mechanism to change the position of the beam spot during scanning.In particular, the controller rotates the dynamic prism to compensate for errors that affect the position of the beam spot on the image surface, such as errors that vary with time and errors that occur randomly during the scanning process.

Abstract: A power of a light beam incident on an optical disk is increased when data is recorded on the optical disk in comparison with the time when the optical disk is played back. A level of a playback signal from the optical disk is held when an operation mode is switched from a playback mode to a recording mode to maintain a stable tracking servo. Furthermore, a signal produced from a photo sensor receiving a reflected beam from the optical disk is reduced when the optical disk is recorded so that a comparatively narrow dynamic range is required in a tracking servo loop.

Abstract: A playback signal from an optical disk includes a track cross component which is produced when a head traverses tracks on the disk and a recorded area component the level of which is reduced in comparison with that of an area on which no data is recorded. A control signal is generated which includes the recorded area component but not the track cross component. A gain of a tracking servo control is controlled by the control signal.

Abstract: During playback of data from a recording medium, a light source emitting a light beam incident on the recording medium is driven by a first drive circuit. During this time, a first control circuit produces a control signal to the first driving circuit and controls the first drive circuit such that a power of the light beam is kept constant. During recording of data, on the other hand, a second drive circuit supplies a drive current in superimposition on a drive current from the first drive circuit with a timing corresponding to the recording data. During this time, the control of the first drive circuit by the first control circuit is inhibited. However, the control signal immediately before the inhibition is held, and hence the light source is continually driven by the first drive circuit. Thus, only a single reference level is necessary for the power control, permitting a simplification of the construction and cost reduction of the apparatus.

Abstract: A playback signal from an optical disk includes a track cross component which is produced when a head traverses tracks on the disk and a recorded area component produced when the head passes an area on the tracks on which data is recorded. The recorded area component is especially affected by a high frequency signal. A control signal which includes the recorded area component but not the track cross component is generated by adjusting the high frequency signal. A gain of a tracking servo control is controlled by the control signal.

Abstract: A playback signal from an optical disk includes a track cross component which is produced when a head traverses tracks on the disk and a recorded area component produced when the head passes an area on the track on which data is recorded. A control signal is generated which includes the recorded area component but not the track cross component. The control signal is also prevented from being affected by a mirror mark which is included in the playback signal. A tracking servo control gain is controlled by the control signal.

Abstract: During playback of data from a recording medium, a light source emitting a light beam incident on the recording medium is driven by a first drive circuit. During this time, a first control circuit produces a control signal to the first driving circuit and controls the first drive circuit such that a power of the light beam is kept constant. During recording of data, on the other hand, a second drive circuit supplies a drive current in superimposition on a drive current from the first drive circuit with a timing corresponding to the recording data. During this time, the control of first drive circuit by the first control circuit is inhibited. However, the control signal immediately before the inhibition is held, and hence the light source is continually driven by the first drive circuit. Thus only a single reference level is necessary for the power control, thus permitting simplification of the construction and cost reduction.

Abstract: An automatic photographing device for a video camera which permits the photographer to enter the picture before the picture recording operation is started and times the picture recording operation to automatically stop after a predetermined period of time. The output of a trigger switch is applied through serially connected first and second timer sections. The first timer section establishes a delay time after the trigger switch is turned on until the picture recording operation commences, while the second timer section establishes the picture recording time. The output of the second timer section controls the operation of the recording device of a photographing section. Further, a display device is provided for indicating distinctively that the delay mode is in effect or that the picture photographing operation is in effect.

Abstract: An automatic focusing device for moving a photographic lens to an optimum focusing position by detecting an object image contrast signal that changes with the varying position of the photographic lens. The device stops the photographic lens while it is being moved between an infinite distance photographing position to a least distance photographing position when the level of the detected contrast signal becomes less than a threshold level. The invention compares a first signal, which is set to correspond to a position at which the photographic lens is to be stopped, and a second signal, which is generated when the contrast signal level is less than the preset threshold level.