Abstract: An optical disk apparatus according to the present invention includes a spindle motor that rotates an optical disk on whose information recording surface a plurality of addresses is recorded, an optical pickup that records/reproduces an information signal on/from the information recording surface of the optical disk rotated by the spindle motor, an strobe light-emitting unit that irradiates a label surface of the optical disk with light, and a control unit that causes the strobe light-emitting unit to emit light based on an address selected from the plurality of addresses as a reference address and a reference signal readable from the optical disk.

Abstract: An apparatus and a method are presented for detecting the focal position of an optical system (10) with a radiation source (12), a focusing imaging system (16), an at least partially reflective surface (18) on the focus (18a), a digital camera (24) for recording an image reflected by said surface (18), a computer (C) for evaluating the image recorded by the camera (24), and with an optical element (34; 36) in the beam path of the optical system (10) upstream of the focusing imaging system (16), which element influences said image depending on the focal position.

Abstract: An optical disc device comprising: first and second laser diodes to radiate first and second laser beams with different first and second wavelengths, respectively; a first objective lens to irradiate the first laser beam to reflection area to read out image recording control data for controlling record of image recorded in the reflection area on label side of optical disc; a second objective lens to irradiate the second laser beam to image recording area to record image in the image recording area on the label side after reading out the data; a lens holder that the lenses are fixed thereon to be arranged side by side in radial direction, to be displaced in direction toward signal side and the radial direction; and a control unit to obtain distance between the lenses in the radial direction to calibrate recording position of image signal recorded in the image recording area.

Abstract: A method for calibrating a focus level on a light scribe disc includes driving a pick-up head with a predetermined speed in a predetermined direction to calibrate a focus level for a moving stage, detecting light summed signals along the light path of the moving stage, and finding and recording the maximum light summed signal and corresponding position of the pick-up head as the focus level for the moving stage. When a number of the moving stages is greater than a predetermined value, the focus level of the moving stage serves as the optimum focus level of the light scribe disc. When the number of moving stages is fewer, lowering the speed with a stage reduction and change the direction opposite to the predetermined direction, and proceeding to a next moving stage to calibrate the focus level.

Abstract: A method for focusing discrete points on an under-measured object is provided. The method includes: (a) receiving an image of the object, selecting measurement points on the image, and obtaining X, Y coordinate values of the measurement points; (b) searching a solid point on the under-measured object according to the X, Y coordinate value of one of the measurement points, wherein the solid point corresponds to the measuring point; (c) emitting a laser light to the solid point for computing a vertical distance “h” between the laser aid and the solid point; (d) computing a Z coordinate value of the measurement point according to the “h”; repeating step (b) to step (d) until all the Z coordinate values of the measurement points have been computed; and (e) focusing the solid points according to the X, Y and Z coordinate values of the measurement points. A related system is also provided.

Abstract: An optical pickup device is equipped with a diffraction element (8) that includes liquid crystal, two transparent electrodes sandwiching the liquid crystal, and a liquid crystal control portion (21) with electrodes connected electrically to the transparent electrode for controlling a voltage to be applied between the two transparent electrodes. The diffraction element (8) is provided with two types of diffraction areas (19) and (20). Each of the diffraction areas (19) and (20) generate predetermined diffracted light only from one of different wavelengths of light beams. The transparent electrodes of the diffraction areas (19) and (20) that are patterned are connected electrically to different electrodes (22c) and (22a), respectively.

Abstract: In multilayer optical discs and high-speed optical discs, the amount of reproduction light per unit time greatly decreases and the reproduction signal quality (S/N) significantly drops due to the low effective reflectivity and the short read time of the medium. These problems are solved by causing reflected signal light from the optical disc and reference light, which is separated from the same light source and introduced into a detector without being shone onto the optical disc, to interference with each other on the detector. Detector outputs having four different interference states are simultaneously obtained, the interference states being displaced at intervals of 90° in terms of the phase relationship between the reference light and the signal. Based on a operation of the four detector outputs, a reproduction signal can be obtained that is stable at all times and amplified with high quality, even when there is an optical path length variation due to disc undulations.

Abstract: An optical pickup apparatus includes a light source to emit light of a predetermined wavelength, an objective lens to focus the light emitted from the light source to form a light spot on an optical disc having a plurality of recording layers, a photodetector to detect a signal and an error signal by detecting the light reflected from the optical disc, and a light scattering portion to reduce an amount of the light reflected from a non-target layer of the recording layers and incident on the photodetector by scattering part of the light reflected from the optical disc during a reproduction of data from the optical disc.

Abstract: The present invention provides an optical pickup system including a first light source emitting a light flux with a first wavelength; a second light source emitting a light flux with a second wavelength; and a light-converging optical system converging the light flux with the first wavelength from the first light source with a first magnification onto a first reference surface set at a first depth, and converging the light flux with the second wavelength from the second light source with a second magnification onto a second reference surface set at a second depth. The first and second wavelengths, the first and second depths, and the first and second magnifications satisfy: a first condition according to an aberration and a second condition according to a working distance.

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 guide shaft and a guide portion movably guide a lens holder for holding a collimator lens (i.e. correction lens) in an optical axis direction. A stepping motor rotates a screw shaft arranged in parallel to the optical axis direction. A nut member converts a rotating movement of the screw shaft into a rectilinear movement of the optical axis direction. An urging spring urges the lens holder against the guide shaft and the guide portion. The lens holder is driven in the optical axis direction along the guide shaft by the stepping motor, with a first contact portion and a second contact portion of the lens holder being contacted with the guide shaft, and a third contact portion of the lens holder being contacted with the guide portion by an urging force of the urging spring. The optical pickup device having the above arrangement allows for stable driving of a correction lens.

Abstract: An optical head device is provided with an objective lens (5) for collecting light emitted from a light source on an optical recording medium (6); a diffraction optical element (8a) for diffracting the reflection light of the emitted light reflected by the recording medium (6) and enters through the objective lens (5); and a photodetector (10a) for receiving a light flux of the reflection light diffracted by the diffraction optical element (8a). The light flux has a first light flux group passed through an area in the diffraction optical element (8a), and a second light flux group passed through a part of the area. The photodetector (10a) detects the first light flux group and the second light flux group by separate photodetector sections (14a to 14h).

Abstract: A pickup device includes an irradiation optical system containing an objective lens for forming a spot by converging a light beam onto a track of a recording surface of an optical recording medium having a plurality of laminated recording layers; and a detection optical system containing a photodetector for receiving, through the objective lens, return light which was reflected and returned from the spot to perform a photoelectric conversion, in which a position of the objective lens is controlled in response to an electric signal arithmetically operated from an output of the photodetector. The photodetector includes a plurality of photosensing element groups which are arranged away from each other on a plane to which an optical axis of the return light penetrates perpendicularly and each of the groups is composed of a plurality of photosensing elements. The pickup device further comprises a dividing element disposed on another plane to which the optical axis of the return light penetrates perpendicularly.

Abstract: An optical head device includes a light source which emits a light beam, an objective lens which condenses the light beam on the optical disk, a condensing lens which condenses reflected light from the optical disk, a liquid crystal panel disposed near a focal point of the condensing lens and having pixels, a driver which drives the pixels of the liquid crystal panel to pass the reflected light from a reproduction layer of the optical disk and partially interrupt the reflected light from a non-reproduction layer of the optical disk, and a photodetector which detects light passed through the liquid crystal panel.

Abstract: The soldered connection of an end portion of a cable extending from each element with a main substrate is prevented from being broken. An end portion of a cable t1 extending from a light source element LD that is fixed to a standing frame 2A on a slide base 2 movable back-and-forth in the radial direction of a disk passes through an insertion opening 9 in the slide base 2 to be connected by soldering 8b to a main substrate 3, and an extended portion 15 extending from the peripheral edge of the insertion opening 9 close to the main substrate 3 is formed integrally with the slide base 2, the clearance “?” between the leading end face 15A of the extended portion 15 and the main substrate 3 being set slightly greater than the thickness “d” of the cable t1, so that the cable t1, if tensioned when positioning the light source element LD, is brought into contact with the edge 15a of the leading end face 15A.

Abstract: An optical head, capable of performing output control for a light source without weakening an intensity of a light beam for recording and reproduction even if an optical element is not added anew, and an optical recording and reproducing apparatus including the optical head. Light fluxes near the center of an optical beam emitted from a light source are made incident on a diffractive element and transmitted through a beam splitter or the like to be irradiated on an optical recording medium. On the other hand, a part of peripheral light fluxes of the light beam are reflected in a direction substantially perpendicular to an optical axis by a reflection surface of a holder provided at an end of the diffractive element. Light beams reflected on the reflection surface are made incident on a photo-detector, and the photo-detector converts the light beams into an electric signal for output monitor of the light source according to an amount of received light.

Abstract: According to an embodiment of the present invention, a semiconductor device used in an optical disk device driving an optical disk, includes: an optical pickup device detecting an optical signal irradiated to the optical disk and converting the detected optical signal into an electric signal to output the electric signal; and a light amount detecting circuit amplifying the electric signal output from the optical pickup device, the optical pickup device including a plurality of light receiving elements different in receiving sensitivity and the light amount detecting circuit including at least one amplifier or two or more amplifiers of the same amplifying characteristics.

Abstract: An optical near-field generating apparatus includes a conductive scatterer causing an optical near-field based on a surface plasmon to be generated by being illuminated by incident light, and a conductive body arranged in a vicinity of the scatterer and generating a surface plasmon by being illuminated by the incident light and by being influenced by the surface plasmon of the scatterer. An oscillation direction of the surface plasmon of the conductive body is approximately parallel to an oscillation direction of the surface plasmon of the scatterer, and a generation region of the surface plasmon of the conductive body exists in a position deviated from a region extending in an oscillation direction of the surface plasmon of the scatterer.

Abstract: An imaging apparatus executes AF control without affecting a video signal and prevents video signal qualities in an in-focus state from decreasing. An optical path separation unit 2 separates light from a subject into first and second light beams. A first imaging unit 3 generates a first signal using the first beam. A second imaging unit 7 generates a second signal using the second beam. A control unit 14 generates a contrast evaluation value based on the second signal while changing an optical-path length of the second light beam by back-or-fourth moving the AF-purpose imaging unit 7 and detects a maximum contrast evaluation value, and executes focus control over an optical system 1 based on the optical-path length corresponding to the detected value. An imaging-purpose signal generation unit 15 generates an imaging-purpose video signal using only the first signal in an out-of-focus state, and using the first and second signals in an in-focus state.

Abstract: The invention relates to an optical pickup for an optical recording medium, an electrically controlled diffraction grating suitable for use in such a pickup, and to an apparatus for reading from and/or writing to optical recording media using such an optical pickup or diffraction grating. According to the invention, an optical pickup for optical recording media having two or more data tracks, with a light source for emitting a light beam for reading from and/or writing to an optical recording medium, includes an electrically controlled diffraction grating, which is switchable between at least two states for generating one or more light beams from the light beam emitted by the light source for reading from and/or writing to one or more of the data tracks.

Abstract: An optical semiconductor device of the present invention includes: a light-receiving element which converts light into an electric signal; an amplifier circuit having an input terminal to which the light-receiving element is connected, and which amplifies the electric signal; a connection wire to which the signal amplified by the amplifier circuit is outputted; an output circuit having an input terminal to which the connection wire is connected, and which performs current amplification on the signal amplified by the amplifier circuit and outputs the current-amplified signal to an output terminal; a feedback resistor connected between the input of the amplifier circuit and the output terminal; and a shield wire connected to a potential outputted from the output circuit or a potential resulting from a voltage follower of the potential outputted from the output circuit, and which shields the connection wire from noise.

Abstract: An optical head device is provided with an objective lens (5) for collecting light emitted from a light source on an optical recording medium (6); a diffraction optical element (8a) for diffracting the reflection light of the emitted light reflected by the recording medium (6) and enters through the objective lens (5); and a photodetector (10a) for receiving a light flux of the reflection light diffracted by the diffraction optical element (8a). The light flux has a first light flux group passed through an area in the diffraction optical element (8a), and a second light flux group passed through a part of the area. The photodetector (10a) detects the first light flux group and the second light flux group by separate photodetector sections (14a to 14h).

Abstract: An optical module includes a first optics group, a second optics group, and an image sensor, wherein the first optics group and second optics group are configured to provide an image having a focus and a magnification to the image sensor. In some embodiments of the present invention, a first optics assembly includes a first optics group coupled to a threaded portion of a first lead screw so that rotation of the first lead screw results in translation of the first optics group along an axis of the first lead screw, a first actuator for rotating the first lead screw; and a first sensing target configured to permit detection of rotation of the first lead screw.

Abstract: An apparatus is described for automatically shifting a lens of a laser focussing optical system, the lens undergoing translational motion along an optical axis, being moved by at least one motor which carries out rotational movement. This rotational movement is converted by a linkage into translational movement to shift the lens.

Abstract: Focus calibration in an optical drive. Optics are moved with respect to a disc in the optical drive. A first interface of the disc is optically detected at a first distance, and a first drive signal value is detected at the first interface. A drive signal change is determined using a second drive signal value at a second distance. A gain is determined using the drive signal change and a thickness associated with the first and second distances.

Abstract: An optical pickup apparatus for recording and/or reproducing information for an optical information recording medium, comprising a light converging optical system including a coupling lens and an objective lens, wherein a first diffraction structure is installed on the objective lens, and a second diffraction structure is arranged on the coupling lens, whereby spherical aberration caused by change of ambient temperature is reduced by giving a condition to reduce the number of areas formed in a ring-shaped of the diffractive structure.

Abstract: Beams of light emitted from a light source are incident on a polarizer. The direction of a transmission axis of the polarizer can be adjusted in advance such that the polarizer transmits P polarized light, and S polarized light is attenuated. Beams of light transmitted through a diffracting device and a collimator lens for incidence on a beam splitter are made up substantially only by P polarized light. Part of the beams of light, which is reflected on the beam splitter, is incident on a photodetector for feedback control of outputs from the light source. Since S polarized light is attenuated by the polarizer, only P polarized light is incident on the photodetector. Consequently, if the quantity of emitted laser beams changes, a ratio between the quantity of light for record and reproduction and the quantity of light for APC remains substantially constant, thereby increasing accuracy of detecting the intensity of laser beams, to avoid errors in record and reproduction.

Abstract: An optical pickup for recording or reproducing information to an optical disk, includes: a first photodetector for detecting a return light from the optical disk, wherein the first photodetector is configured so that the first photodetector is divided into three portions in a radial direction corresponding to a radial direction of the optical disk and light receiving elements at both end portions in the radial direction are divided into three portions in substantially a track direction perpendicular to the radial direction, so that the first photodetector includes a light receiving element at a central portion in the radial direction and the three light receiving portions at each of both the end portions to be seven in total to output a light receiving element signal based on light reception of the return light as a track error signal generation signal.

Abstract: An optical head device includes a light source which emits a light beam, an objective lens which condenses the light beam on the optical disk, a condensing lens which condenses reflected light from the optical disk, a liquid crystal panel disposed near a focal point of the condensing lens and having pixels, a driver which drives the pixels of the liquid crystal panel to pass the reflected light from a reproduction layer of the optical disk and partially interrupt the reflected light from a non-reproduction layer of the optical disk, and a photodetector which detects light passed through the liquid crystal panel.

Abstract: Light emitted from alight source (5) is reflected by the reflection film of a polarized beam-splitter (6), passes through collimating lens (7) and a mirror (8) to reach a convergence lens (9). The convergence lens (9) forms a light spot on an information medium (1) having a visual information layer (4). Reflected light which is reflected by the visual information layer (4) passes through the convergence lens (9), the mirror (8), and the collimating lens (7), transmits through the reflection film of the polarized beam-splitter (6), passes through a half mirror (14) to reach a second light detector (13). The second light detector (13) detects an FE signal for the visual information layer (4) and feeds back the detected signal to an LPC circuit, thereby restricting power fluctuation due to surface deflection.

Abstract: A light analyzer device and a method for detecting objects utilizing the light analyzer device are provided. The light analyzer device includes a focal plane array configured to receive the light that has passed through a light filter and to generate a first digital image based on the light that has passed through the light filter. The light analyzer device further includes a microprocessor operably coupled to the focal plane array. The microprocessor is configured to receive the first digital image, and to determine whether the first digital image corresponds to a stored digital image. The light analyzer device further includes a light emitting device operably coupled to the microprocessor. The microprocessor is further configured to induce the light emitting device to output a visual indicator indicating that the first digital image corresponds to the stored digital image.

Abstract: An optical pickup apparatus includes a first objective lens having a low numerical aperture (NA) suitable for a low density recording medium, a second objective lens having a high NA suitable for a high density recording medium, a first light source that emits short wavelength light which is focused onto an optical recording medium by the first and second objective lenses, a first photodetector that receives a returning reflected light from the optical recording medium, and a first optical path converter for selectively guiding part of the light emitted from the first light source towards the first or the second objective lens, and guiding the reflected light towards the first photodetector.

Abstract: Light receiving elements for receiving a + one-dimensional light divided into four are arranged in the vicinity of a light receiving part for receiving the zero-dimensional light. Some light receiving elements configure the light receiving elements of a first group for receiving the + one-dimensional light forming a focus on the front side of the light receiving surface, and the other light receiving elements configure the light receiving elements of a second group for receiving the + one-dimensional light forming a focus on the rear side of the light receiving surface. A correction value is calculated based on a difference in the outputs of the light receiving elements belonging to the first group and a difference in the outputs of the light receiving elements belonging to the second group, and the focus error signal is corrected using the correction value.

Abstract: It is an object of the present invention to provide an analysis apparatus which can achieve an image with a proper contrast even from an analysis object on an analysis optical disc. When an image is obtained from an analysis object 111, a control unit (210) switches a switch (208) in such a way that a detection signal of laser light has a constant average value, the laser light having been emitted to the analysis optical disc and reflected thereon or passed therethrough, and the control unit (210) feeds back the output signal of an integrating circuit (209) to an APC circuit (115) for controlling a laser drive circuit (116).

Abstract: An optical near-field generating apparatus includes a conductive scatterer causing an optical near-field based on a surface plasmon to be generated by being illuminated by incident light, and a conductive body arranged in a vicinity of the scatterer and generating a surface plasmon by being illuminated by the incident light and by being influenced by the surface plasmon of the scatterer. An oscillation direction of the surface plasmon of the conductive body is approximately parallel to an oscillation direction of the surface plasmon of the scatterer, and a generation region of the surface plasmon of the conductive body exists in a position deviated from a region extending in an oscillation direction of the surface plasmon of the scatterer.

Abstract: A previous amplifier circuit of the present invention includes: a grounded emitter amplifier circuit using a grounded emitter transistor connected to a light receiving device; another grounded emitter amplifier circuit using another grounded emitter transistor connected to another light receiving device; and a grounded emitter changing switch to be switched in a manner such that an emitter of the grounded emitter transistors is grounded so as to cause only one of the grounded emitter amplifier circuits to operate. A light-receiving amplifier circuit includes the previous amplifier circuit. An optical pickup apparatus includes the light-receiving amplifier circuit.

Abstract: An optical pickup device has three different light sources, a holographic element, beam splitters, and first and second photodetectors. The beam splitters each change an optical path of a light beam coming from the associated light source toward a recording medium and match an optical axis of the changed optical path with an optical axis passing through the holographic element and the first photodetector. Reflected light from the recording medium is divided into zero-order diffraction light and first-order diffraction light by the holographic element. The first photodetector receives the zero-order diffraction light and obtains an RF signal and a tracking error signal. The second photodetector receives the first-order diffraction light and obtains a focusing error signal.

Abstract: Disclosed is a light receiving device for reading an optical medium compliant with any of different standards. The receiving device includes light receiving elements and an amplifier circuit. Each light receiving element is for receiving light reflected from an optical medium compliant with a different one of the standards and output a signal responsive to the received light. The amplifier circuit is for amplifying a signal derived from output of the light receiving elements. The signal amplified by the amplifier circuit is derived by subtracting an output signal of one of the light receiving elements that receives light from the optical medium from an output signal of the other light receiving elements.

Abstract: An optical pickup apparatus includes a light source to emit light of a predetermined wavelength, an objective lens to focus the light emitted from the light source to form a light spot on an optical disc having a plurality of recording layers, a photodetector to detect a signal and an error signal by detecting the light reflected from the optical disc, and a light scattering portion to reduce an amount of the light reflected from a non-target layer of the recording layers and incident on the photodetector by scattering part of the light reflected from the optical disc during a reproduction of data from the optical disc.

Abstract: An optical disk apparatus includes a light emitting unit, a light detecting unit, a tracking error signal generating unit, and a tracking control unit. The light emitting unit emits a single light beam onto an optical disk. The light detecting unit includes at least three light detecting portions, each being configured to receive light reflected off the optical disk and produce corresponding output. The at least three light detecting portions are arranged in a track direction of the optical disk. The tracking error signal generating unit generates at least two types of the tracking error signal using the outputs from the at least three light detecting portions. The tracking control unit performs tracking control on the optical disk on the basis of the tracking error signal.

Abstract: A method is provided to detect whether vertical deviation occurs as an optical disc spins in an optical disc player having a pickup head pre-installed in a balanced position at a focal distance. When moving towards and away from the balanced position, the pickup head generates a focus error signal with an S-curve. According to an input control signal, a focus actuator actuates the pickup head to keep it substantially at the focal distance. When the pickup head is not focused, the waveform of the input control signal is designed to actuate the pickup head back and forth within a predetermined range to generate the focus error signal with S-curves. Zero crossing points of S-curves are identified and input control values in the input control signal are obtained accordingly. The variation of the input control values is calculated, and whether vertical deviation occurs is determined by a predetermined procedure.

Abstract: A semiconductor light receiving element has: a semiconductor substrate; a plurality of photodiodes formed on the semiconductor substrate and configured to receive respective lights of different wavelengths; and an anti-reflection film provided on light receiving surfaces of the plurality of photodiodes. A structure of the anti-reflection film on at least one photodiode of the plurality of photodiodes is different from a structure of the anti-reflection film on another photodiode of the plurality of photodiodes.

Abstract: A correlation operation method includes: first processing executed to match a signal level of an AC component contained in a first signal data string made up with a plurality of sets of first signal data with a signal level of an AC component contained in a second signal data string made up with a plurality of sets of second signal data; and correlation degree calculation processing executed to calculate a correlation degree indicating a degree of correlation between the first signal data string and the second signal data string having undergone the first processing.

Abstract: An apparatus and method for controlling a focus jump between recoding layers in a high-density multi-layer disk. The apparatus includes: an optical pickup including an objective lens focusing light on the disk, an aberration correcting unit, and a photodetector detecting light reflected from the disk; a signal processing unit generating a focus error signal from a signal output by the photodetector; a focus hold unit holding a focus servo of the optical pickup; a focus servo control unit controlling the focus servo of the optical pickup using the focus error signal; and a driving unit driving the optical pickup using a signal output by the focus servo control unit.

Abstract: An optical pickup with a reflective coating device is provided, including a laser diode (LD), an optical element, and a photo detector integrated circuit (PDIC). The LD emits 1-3 lights with different wavelengths but the same polarization orientation. The beam transmits through the optical element set and focus on a recording media for data reading and writing. The beams are reflected by the recording media, through the optical element set, and detected by the PDIC for signal detection. The optical element set further includes a grating, a reflective coating device, and an objective lens. By using the reflective coating device to change the linear polarization orientation of the emitting light and the feedback light for 90° angle, the relative intensity noise caused by the feedback light in LD can be reduced.

Abstract: An optical head device includes a light source which emits a light beam, an objective lens which condenses the light beam on the optical disk, a condensing lens which condenses reflected light from the optical disk, a liquid crystal panel disposed near a focal point of the condensing lens and having pixels, a driver which drives the pixels of the liquid crystal panel to pass the reflected light from a reproduction layer of the optical disk and partially interrupt the reflected light from a non-reproduction layer of the optical disk, and a photodetector which detects light passed through the liquid crystal panel.

Abstract: An optical device diffracts incident light with a hologram element 19 and receives the diffracted light with light receiving regions 20A to 29 on a light receiving element 12. The light receiving element 12 separately receives reflected main beams used to read information from an optical disc and reflected sub-beams used for a tracking operation with different ones of the light receiving regions. The light receiving regions to receive the reflected main beams are common irrespective of the wavelengths of the reflected main beams. The light receiving regions to receive the reflected sub-beams are different depending on the wavelengths of the reflected sub-beams. The optical device can record and/or reproduce information signals to and/or from optical discs, which need light sources of different wavelengths, without the influence of unnecessary reflected light from the optical discs or without complicating operation of output signals.

Abstract: A printer has a laser emitter for emitting a laser beam to irradiate a surface of a photosensitive member; a reflector, disposed at a position on a laser beam path defined by the laser emitter and the photosensitive member, for reflecting the laser beam emitted by the laser emitter to direct the reflected laser beam to a target position on the surface of the photosensitive member; a reflective mirror driver for reciprocating the reflector in such a manner that the laser beam travels along a scanning line on the surface of the photosensitive member in a direction for scanning; and an emission controller for controlling the laser emitter to selectively emit the laser beam along the scanning line in the forward direction or the backward direction defined by the movement of the reflector driven by the reflective mirror driver.

Abstract: The present invention relates to an optical medium judging method for avoiding the collision of an objective lens with a disk or the failure to judge a warped disk when the optical disk drive judging the disk. This method will move the objective lens so as to obtain the data of the laser beam reflection amount of the focusing beam on the plastic layer of the optical disk. By using the reflection amount, the driving circuit will output a rising direct current voltage of a voltage difference to drive an actuator so as to move the objective lens to a proper position capable of judging the disk without colliding with the disk.

Abstract: A photodetector to be incorporated in an optical pickup device, comprising: a photodiode that a laser light emitted from a laser diode is applied to and that outputs a signal corresponding to light amount of the laser light; and a translucent resin member configured to cover the photodiode, including a light receiving portion that the laser light is applied to and that causes the laser light to be applied to the photodiode, and a peripheral portion provided around the light receiving portion, the light receiving portion being smaller in thickness than the peripheral portion.