Abstract:
A heat source having a device emitting heat, a case protecting and supporting the device, and a thermoelectric element absorbing the heat emitted from the device and dissipating the heat to an outside.
Abstract:
In order to improve the frequency characteristic of a laser power monitor device and the precision of laser power control when low-speed recording is performed, there is provided a laser power monitor device for an optical recording and/or reproducing apparatus, the laser power monitor device including a photo diode unit to receive part of a light emitted from a laser diode and output a current proportional to optical power, and a monitor circuit to receive the current output from the photo diode unit, convert the received current into a voltage, and outputs the voltage to an automatic laser power control circuit, and the photo diode unit includes a plurality of photo diodes connected to the monitor circuit to supply current to the monitor circuit. The laser power monitor device further includes a switch unit, wherein the switch unit is located between the photo diode unit and the monitor circuit to receive a signal on a current recording speed and switch so that the number of photo diodes supplying current to the monitor circuit is reduced as the recording speed is increased.
Abstract:
An optical disc recording method to record data on a disc using multiple speeds by dividing a disc region into an inner circumference region and an outer circumference region depending on radii of the disc, setting a multiple recording speed for each region; setting optical recording power in a lead-in region of the inner circumference region and a lead-out region of the outer circumference region, by performing optimum power controls therein; determining in which one of the divided regions data is to be recorded using an address detected from the disc, rotating the disc at the multiple recording speed set for the one region in which the data is to be recorded, and recording the data in the one region using the set optical recording power for the one region.
Abstract:
An optical pickup device employing a signal detection unit including a hologram element having a plurality of pattern regions for diffracting and/or focusing light reflected and incident from a recording medium, a photodetector having a plurality of light receiving regions for receiving and photoelectrically converting the light diffracted by the hologram element and a signal operation unit for generating a focus error signal and/or a track error signal from a signal detected from the photodetector. The optical pickup device can implement a stable servo operation even at deviations of the photodetector, a change in the wavelength of light emitted from the light source, and/or shift of focusing means such as an objective lens, and can record and/or reproduce high-density information on/from the recording medium.
Abstract:
A light emitting module packaging two light sources emitting two light beams of different wavelengths, and a compatible optical pickup device adopting the module are provided. The light emitting module includes a base, first and second light sources installed on the base, for emitting laser beams in different wavelength regions, a beam splitter and a monitoring photodetector for monitoring the optical outputs of the first and second light sources by receiving the beams emitted from the first and second light sources and split from the beam splitter in one direction. Also, another light emitting module includes a substrate, first and second light sources installed on the substrate for emitting laser beams of first and second wavelengths from both lateral sides thereof, a reflection member for reflecting the laser beam emitted from one lateral side of each of the first and second light sources to proceed in one direction, and first and second monitoring photodetectors for monitoring optical outputs of the first and second light sources. The compatible optical pickup device includes the light emitting module having the above structure, an objective lens for focusing first and second laser beams on an optical recording medium, an optical path converting device, a grating arranged on an optical path between the light emitting module and the optical path converting device for diffracting and transmitting an incident light, a photodetector.
Abstract:
An optical pickup includes a rotary block rotatably installed on a fixed base; a holder integrally coupled to the rotary block; a bobbin supported by a wires of the holder to be movable; a base plate fixed to the fixed base and placed between the rotary block and the bobbin; an objective lens mounted in the bobbin, for focusing an incident light to form a spot of light on a recording medium; a focusing coil and tracking coils installed in the bobbin, serving as a current flow path for focusing and tracking operations; first magnets and first inner and outer yokes installed in the base plate, facing the focusing coil and the tracking coils, for producing magnetic fields perpendicular to the current flowing through the focusing coil and the tracking coils to produce an electromagnetic force for driving the bobbin; a fixed optical system for irradiating light toward the recording medium and receiving the light reflected by the recording medium and then passed through the objective lens; a reflecting mirror for changing the traveling path of the incident light, the reflecting mirror installed in the rotary block to be arranged between the objective lens and the fixed optical system; tilt coils serving as a current flow path, the tilt coils installed at both sides of the rotary block; and second magnets and second inner and outer yokes installed facing the tilt coils, for producing magnetic fields perpendicular to the current flowing through the tilt coils to produce an electromagnetic force for rotating the rotary block. Therefore, the tilt of the optical axis of the light incident onto and reflected by an optical disk through the reflecting mirror and the objective lens can be adjusted according to the tilt of the recording medium, such that the light is perpendicularly incident onto and reflected by the recording medium all the time.
Abstract:
A fast responding optical modulating device for a high-density recording using in an optical pickup includes a light source, an optical modulator and a pair of lenses. The pair of lenses are so arranged that the distance between the lenses is shorter than the sum of each focal length of the lenses. The device can adjust an optical spot size at the center of the optical modulator by changing the position of the lenses without altering the whole length between the light source and optical modulator. Therefore, the device can increase the rise time as desired and the optical efficiency in optical modulation for high-density recording which uses a short wavelength light source, and moreover, has an effect of simplifying the high-density recording.
Abstract:
A front photo detector (FPD) of an optical pick-up for an optical recording and playing apparatus having no gain selection switch, a simplified configuration, an improved prevention of an abnormal operation due to an error in gain selection, and improved reliability. The front photo detector includes a photo diode unit, a current-voltage amplifying circuit, and a voltage amplifying unit. The photo diode unit outputs current proportional to the power of the light emitted from one of a plurality of laser diodes. The current-voltage amplifying circuit converts the current output from the photo diode unit into a voltage. The voltage amplifying circuit amplifies the voltage output from the current-voltage amplifying circuit by a predetermined gain.
Abstract:
A method and apparatus for compensating tilt. The tilt compensation method includes: obtaining one of a jitter best, an RF envelope, and a focus DC offset (FODC) from a detection signal of the ROM data region and determining whether the obtained value is within a tolerance range; and obtaining an initial skew compensation value using the obtained value when the obtained value is within the tolerance, changing the magnitude of current applied to an actuator designed to perform driving in at least three-axis directions to drive an objective lens of an optical pickup assembly in a radial tilt direction when the obtained value is not within the tolerance range, and repeating the obtaining of one of the jitter best, the RF envelope, and the FODC and changing the magnitude of the current until the obtained value is within the tolerance range.
Abstract:
A compatible optical pickup, including first and second light sources for emitting lights with different wavelengths and first and second photodetectors for detecting an information signal and/or an error signal, and a method of detecting the amount of output light using the compatible optical pickup. The first and second photodetectors monitor the amount of light output from the second and first light sources respectively such that no extra front photodetectors are required. Thus, the number of optical component parts included in the optical pickup can be reduced, thereby lowering the manufacturing costs for the optical pickup. Also, there is no need to secure a space in a base where a front photodetector is to be installed, so the base is simplified. Thus, inferior moldings are reduced, and the durability of a mold can be prolonged.