摘要:
An optical head has a semiconductor laser for emitting light, a collimator lens for converting the light from the laser into a parallel light beam, a semiconductor substrate for reflecting the light beam, and an objective lens for focussing the light beam reflected from the substrate on the optical disk. A 1/4 wavelength plate is situated between the substrate and the objective lens. A beam splitter which transmits the light from the laser and reflects the light returning from the disk is provided between the collimator lens and the substrate. Following the beam splitter, a collective lens, a cylindrical lens and an optical detector are arranged in this order on an optical path for the returning light. A light receiving element for outputting a signal corresponding to the intensity of the light received is formed on the semiconductor substrate, and a polarizing film is formed on the surface thereof.
摘要:
An optical pick-up apparatus for reproducing information recorded on a magneto-optical record medium including a semiconductor laser emitting a linearly polarized laser beam, and a polarizing film provided between a glass prism and a uniaxial birefringent crystal prism. The laser beam emitted by the semiconductor laser is made incident upon the polarizing film via the glass prism and is reflected thereby. The apparatus further includes an objective lens projecting the laser beam reflected by the polarizing film onto the magneto-optical record medium as a fine spot and converging a return laser beam reflected by the record medium toward the polarizing film. The return beam transmitted through the polarizing film is refracted by the uniaxial birefringent crystal prism and is divided into ordinary light and extraordinary light, which are received by a first photodetector to produce a reproduced information signal. The return beam reflected by the polarizing film is made incident upon a hologram and is diffracted thereby into .+-.1-order beams which are received by a second photodetector to produce a focusing error signal and a tracking error signal.
摘要:
A spectroscope includes an emitting portion from where light is output, a dispersive element which is disposed on a side of the light emitting portion, to which the light is output, an incidence portion on which, light dispersed by the dispersive element is incident, and a temperature-compensating element which is disposed between the emitting portion and the incidence portion, and which is such that, an angle of incidence of the light dispersed on the incidence portion becomes almost constant with respect to a change in temperature in an operating temperature range. Moreover, the optical apparatus has such spectroscope in which temperature is compensated.
摘要:
An optical head for writing and/or reading information on and/or from an optical record medium such as a magneto-optical record medium including a semiconductor substrate, a semiconductor laser mounted on a surface of the semiconductor substrate for emitting a laser beam, an objective lens for projecting the laser beam onto the optical record medium as a fine spot, a plurality of photodetectors firmed in the surface of the semiconductor substrate, and an optical block arranged on said semiconductor substrate to form an integral unit together with said semiconductor substrate. The optical block includes a hologram for diffracting a return beam reflected by said magneto-optical record medium and a polarization beam splitting plane arranged in substantially parallel with an optical axis of a zero order beam emanating from the hologram for splitting a pupil of the hologram. The return beams diffracted by the hologram and split by the polarization beam splitting plane are separately received by the plurality of photodetectors. By processing outputs of the photodetectors, information signal, focusing error signal and tracking error signal can be derived in a reliable and stable manner, while the optical head can be simple in construction, small in size and cheap in cost.
摘要:
A spectroscope includes an emitting portion from where light is output, a dispersive element which is disposed on a side of the light emitting portion, to which the light is output, an incidence portion on which, light dispersed by the dispersive element is incident, and a temperature-compensating element which is disposed between the emitting portion and the incidence portion, and which is such that, an angle of incidence of the light dispersed on the incidence portion becomes almost constant with respect to a change in temperature in an operating temperature range. Moreover, the optical apparatus has such spectroscope in which temperature is compensated.
摘要:
An optical switch includes a plurality of light inputting members, a plurality of light outputting members, an optical coupling member which couples light to the light inputting members and the light outputting members, an optical path changing member which changes an optical path from the light inputting members up to the light outputting members, an optical path shielding member which can take a first position which shields collectively all optical paths from the light inputting members up to the light outputting members and a second position which allows light to pass through the optical path, a first driving circuit which drives the optical path changing member, and a second driving circuit which drives the optical path shielding member.
摘要:
The present invention is directed to an apparatus using an integrated type pickup as an optical head for writing and reading optical information and capabling of writing data at high speeds. The apparatus includes a laser diode having an active layer at its intermediate position and having one area side held over a surface of a semiconductor substrate with an insulating layer interposed between the semiconductor substrate and the laser diode relative to the active layer. The laser diode has two areas with the active layer as a boundary and a constant potential is applied from a power supply to the insulating layer side of the laser diode and a transistor (laser diode drive unit) is provided to apply a modulation signal to the other area of the laser diode so that the laser diode is driven to modulate its output. By doing so, a constant potential is maintained at the semiconductor substrate and at the insulating layer's side of the laser diode and the modulation signal is applied to the other area side of the laser diode. When a drive current of the laser diode is varied by the modulation signal, a voltage variation occurs only on the other area side of the laser diode so that a high-frequency drive current, if flowing through the insulating layer side, is small and hence the laser diode has its output to be modulated effectively.
摘要:
A highly reliable optical switch which can output (switch) accurately to an optical fiber for output without being affected by a change in an environment and a change due to an elapsed time is provided. The optical switch includes a first spectroscope which separates spatially light from an optical fiber for input according to a wavelength and a mirror array which includes a plurality of mirrors which reflect separated light and an angle of each of the mirrors can be controlled independently by an electric signal. The optical switch further includes An optical branching device which extracts a part of an output light from the optical fiber for output, an optical fiber for monitoring which guides apart of output light extracted by the optical branching device, a second spectroscope which separates spatially light from the optical fiber for monitoring according to a wavelength, and a photodetector array which can detect lights of different wavelengths separated at the second spectroscope.
摘要:
A laser beam emitted from a laser source provided at a silicon substrate passes through a hologram element formed of a translucent flat plate and a grating, thereby being subjected to NA conversion executed by an NA converting lens, passing through a polarizing film of a polarization beam splitter, and converging onto a magneto-optical disk via a collimator lens and an objective. A part of back-reflection from the magneto-optical disk, which is reflected by a polarizing film of the polarization beam splitter, is reflected by a reflection surface of the splitter, then branched into two polarized light beams by a Wollaston prism, and guided to one light receiving element group. On the other hand, another part of the back-reflection, which passes through the polarization beam splitter, is branched into two beams by the hologram element and guided to the other light receiving element groups.
摘要:
The present invention avoids a loss of information recorded on or information to be recorded onto an optical disk by accepting a state of deterioration of a semiconductor laser in a closed-type optical disk apparatus. The optical disk is rotated in a predetermined direction by a driving of a spindle motor through a motor driver based on an instruction from a control section. Information is recorded onto or reproduced from the optical disk by a semiconductor laser driven through a laser driver based on an instruction from the control section. The state of progress of deterioration of the semiconductor laser is monitored by a monitoring section, and this state is displayed by a light display section according to a deterioration state.