WO2006006296A1 - 光ピックアップ装置および光ディスク装置 - Google Patents
光ピックアップ装置および光ディスク装置 Download PDFInfo
- Publication number
- WO2006006296A1 WO2006006296A1 PCT/JP2005/008591 JP2005008591W WO2006006296A1 WO 2006006296 A1 WO2006006296 A1 WO 2006006296A1 JP 2005008591 W JP2005008591 W JP 2005008591W WO 2006006296 A1 WO2006006296 A1 WO 2006006296A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- light
- pickup device
- optical pickup
- recording
- lens holder
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/13—Optical detectors therefor
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/095—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for discs, e.g. for compensation of eccentricity or wobble
- G11B7/0956—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for discs, e.g. for compensation of eccentricity or wobble to compensate for tilt, skew, warp or inclination of the disc, i.e. maintain the optical axis at right angles to the disc
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1362—Mirrors
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1372—Lenses
- G11B7/1374—Objective lenses
Definitions
- the present invention relates to an optical pickup device that records and reproduces information by irradiating an optical disc with a recording and reproducing laser beam from a light source by tilting and horizontally driving a lens holder that holds an objective lens.
- An optical pickup apparatus records and reproduces information by irradiating a recording surface of an optical disc with a recording and reproducing laser beam.
- the objective lens is attached with high accuracy in the manufacturing stage.
- Japanese Laid-Open Patent Publication No. 2000-57585 discloses an objective lens tilt monitor device that can adjust the mounting tilt of the objective lens with high accuracy. This irradiates light around the objective lens, and detects the light intensity of the reflected light and the return position force of the objective lens. According to this, the objective lens can be attached with high accuracy.
- the objective lens and the optical disk may not be parallel due to warpage of the optical disk itself. Therefore, test irradiation is performed on the recorded area of the optical disc while changing the tilt angle of the objective lens, and the tilt angle of the objective lens when the reproduction quality exceeding the reference value is obtained is acquired and stored as the reference tilt angle. Tilt correction that corrects the tilt angle of the objective lens based on the reference tilt angle is employed. According to this, even if the optical disk is warped, the objective lens and the optical disk can be kept parallel, and the reliability of information recording and reproduction can be improved.
- this reference tilt angle has been stored as an applied voltage value of a driving device that drives the objective lens to tilt.
- the driving device is two electromagnetic coils that apply vertical thrust to the left and right sides of the objective lens.
- the tilt angle was different even at the same voltage value. In other words, the correspondence between the applied voltage value and the tilt angle may not match. For this reason, there is a problem that even if the stored voltage value is applied, the objective lens does not become the reference inclination angle, and the recording / reproducing accuracy is lowered.
- an object of the present invention is to provide an optical pickup device that can further improve the recording / reproducing accuracy.
- the optical pickup device of the present invention records and reproduces information by irradiating a recording / reproducing laser beam from a light source onto an optical disc by tilting and horizontally driving a lens holder that holds an objective lens.
- a reflector that is provided in the lens holder and reflects a part of the recording / reproducing laser beam guided from the light source to the lens holder, and a reflected reflected light for detection that is the recording / reproducing laser beam reflected by the reflector.
- a light detection means fixedly arranged at a position where the amount of received light changes according to the inclination angle of the lens holder, and an inclination angle acquisition means for acquiring the inclination angle of the objective lens from the received light amount detected by the light detection means. It is characterized by having.
- the tilt angle acquisition means obtains the tilt angle by removing the change in the received light amount of the photodetector caused by the horizontal driving of the lens holder from the received light amount detected by the light detection means.
- the recording / reproducing laser beam has a known non-uniform light intensity distribution
- the tilt angle acquisition means is configured to detect the inclination of the lens holder from the change in the light intensity of the entire reflected reflected light for detection caused by horizontal driving. A change in the amount of light received by the photodetector due to horizontal driving is acquired.
- the recording / reproducing laser beam is larger than the aperture of the objective lens and is set to a beam diameter
- the reflector is positioned to reflect the recording / reproducing laser beam that is not incident on the objective lens.
- the lens holder has an aperture limiting portion that limits the beam diameter of the recording / reproducing laser beam incident on the objective lens, and the reflector is provided in the aperture limiting portion.
- the optical path of the signal light that is the recording / reproducing laser light reflected by the optical disc is the same direction as the optical path of the reflected light for detection, and the reflector is Provided at an angle, the reflected reflected light is guided slightly away from the signal light to the photodetector.
- the signal light polarizing means for polarizing the signal light at a different polarization angle from the incident light the reflected light polarizing means for polarizing the detection reflected light at the same angle as the signal light, and the polarization angle
- a polarization beam splitter that separates the optical path directions of the incident light, the signal light, and the reflected light for detection.
- a plurality of reflection surfaces of the reflector are formed in a stepped shape.
- Another optical disc apparatus is an optical disc apparatus that records and reproduces information by irradiating an optical disc with a recording / reproducing laser beam by an optical pickup device, and includes any of the optical pickup devices described above.
- Storage means for storing the tilt angle of the lens holder when a reproduction quality satisfying a predetermined standard is obtained in test irradiation on the optical disc as a reference tilt angle, a reference tilt angle stored in the storage means, and a current lens holder
- a control means for driving and controlling the lens holder to be the reference inclination angle based on the deviation of the inclination angle of the optical pickup device.
- the reference inclination angle and the current inclination angle of the lens holder are determined by the optical pickup device.
- the predetermined standard includes a standard that the value of a parameter indicating reproduction quality such as a jitter single value or an error rate is “predetermined standard value or more” and a standard that is “best”.
- FIG. 1 is a schematic configuration diagram of an optical pickup device according to an embodiment of the present invention.
- FIG. 2A is a diagram showing the basic principle of the present invention, and is a diagram showing the light intensity detected by the detector when the lens holder is tilted.
- FIG. 2B is a diagram showing the basic principle of the present invention, and is a diagram showing the light intensity detected by the detector when the lens holder is tilted.
- FIG. 2C is a diagram showing the basic principle of the present invention, and is a diagram showing the light intensity detected by the detector when the lens holder is tilted.
- FIG. 3A is a diagram showing a basic principle of the present invention, and is a diagram showing light intensity detected by a detector when the lens holder is driven horizontally.
- FIG. 3B is a diagram showing the basic principle of the present invention, and is a diagram showing the light intensity detected by the detector when the lens holder is driven horizontally.
- FIG. 3C is a diagram showing the basic principle of the present invention, and is a diagram showing the light intensity detected by the detector when the lens holder is driven horizontally.
- FIG. 4 is a configuration diagram of an optical disc apparatus according to an embodiment of the present invention.
- FIG. 5 is a schematic configuration diagram of an optical pickup device.
- FIG. 6 is a peripheral view of the lens unit of the optical pickup device.
- FIG. 7A is a bottom view of the lens unit of the optical pickup device.
- FIG. 7B is a cross-sectional view taken along the line AA in FIG. 7A.
- FIG. 7C is a BB cross-sectional view in FIG. 7A.
- FIG. 8A is a diagram showing an example of the arrangement of photodetectors.
- FIG. 8B is a diagram showing an example of the arrangement of photodetectors.
- FIG. 9 is a schematic configuration diagram of an optical pickup device according to another embodiment.
- FIG. 10 is a schematic bottom view of an optical pickup device according to another embodiment.
- FIG. 1 is a schematic configuration diagram of the optical pickup device 10.
- the optical pickup device 10 condenses recording / reproducing laser light emitted from a light source (not shown) by an objective lens 14 and irradiates the recording surface of the optical disc 12 to record or record information. Perform playback.
- the recording / reproducing laser beam reflected by the recording surface of the optical disk 12 returns as signal light 25 containing information, and is provided in the light receiving unit 20 through an optical path different from the incident optical path by an optical system such as a beam splitter 21. Light is received by a photo detector.
- Examples of the optical disk 12 include CD player RZRW, DVD player RZRW, HD—DVD, and BLU—RAY.
- the objective lens 14 is disposed to face the optical disk 12 and is held by a lens holder 16.
- the lens holder 16 can be driven horizontally, vertically, and tilted by a drive source (not shown).
- the optical axis of the laser beam irradiated onto the optical disc 12 Is perpendicular to the optical disk 12, in other words, the objective lens 14 and the optical disk 12 must be parallel.
- the recording / reproducing laser light is short-wavelength light, and a slight tilt of the optical axis greatly affects the increase in coma.
- each component of the optical pickup device 10 including the objective lens 14 is assembled with high accuracy in the manufacturing stage.
- the parallelism with the objective lens 14 may not be maintained due to the warp of the optical disk 12 or the like.
- the amount of warpage varies from one optical disc 12 to another and cannot be dealt with uniformly. Therefore, in order to cope with the warp that occurs in each individual optical disk, conventionally, tilt correction that inclines the objective lens 14 in the radial direction and maintains parallelism with the optical disk 12 has been employed.
- the objective lens 14 is appropriately tilted so as to have a pre-stored reference tilt angle.
- the reference tilt angle is obtained by first performing test playback by irradiating the recorded area of the optical disc 12 with a recording / playback laser beam while changing the tilt angle of the objective lens.
- the tilt angle when the playback quality that is the best or above the specified reference value is obtained is taken as the reference tilt angle.
- group SCM playback may be used instead of data playback of the recorded area.
- the best playback quality means that the playback output level of the inner group SCM is the same as the playback output level of the outer group SCM. The difference between the two playback output levels is within the allowable value.
- the stored reference inclination angle and the actual inclination angle detected at the time of recording / reproducing information must match.
- accurate inclination angle detection is required. Therefore, in this embodiment, a reflector, a detector for detection, and the like described below are provided to detect the tilt angle of the objective lens. This will be described below.
- a reflector 18 having a force such as a mirror is provided in the lens holder 16 in order to detect the tilt angle. If the reflector 18 can reflect a part of the incident laser beam 22 that is a recording / reproducing laser beam incident on the lens holder 16, its position and size are particularly limited. Absent. However, in order not to disturb the recording / reproducing of information, it is desirable to provide it at a position that reflects the incident laser beam 22 that is not used for recording / reproducing of information. Specifically, a position where the beam diameter of the incident laser beam 22 is larger than the incident aperture to the objective lens 14 and a position on the outer side of the incident laser beam 22 can be reflected is desirable. In addition, the number of the reflectors 18 may be single or plural, and may be shifted, but it is desirable to provide a plurality of reflectors apart from each other.
- the recording / reproducing laser beam reflected by the reflector 18 becomes the detection reflected light 24 used for detecting the tilt angle.
- the reflected light for detection 24 is received by a detection detector provided in the light receiving unit 20 after its optical path is appropriately controlled by an optical system such as the polarization beam splitter 21.
- the optical path of the detection reflected light 24 be in substantially the same direction as the signal light 25 reflected by the optical disc 12.
- the detector for reading information and the detector for detection can be arranged close to each other, the configuration of the entire optical pickup device 10 can be simplified, and the size can be reduced.
- the optical path of the detection reflected light 24 is slightly outward in the radial direction from the optical path of the signal light 25. This can be realized by inclining the reflecting surface of the reflector 18 outward in the radial direction. In some cases, the optical paths of the signal light 25 and the detection reflected light 24 may be completely different.
- the detection detector is a photodetector that receives the reflected reflected light 24 for detection. This is provided at a position where the amount of received reflected light 24 for detection changes according to the inclination of the lens holder 16. Further, when there are a plurality of reflectors 18, that is, when there are a plurality of detection reflected lights 24, it is desirable that a detection detector is also provided for each of the detection reflected lights 24. In addition, the detector for detection corresponding to each reflector 18 may be a single photodetector, but is preferably a plurality of divided photodetectors.
- the light intensity detected by the detector for detection is converted into an electric signal and then output to an arithmetic unit (not shown).
- the calculation unit functions as a tilt angle acquisition unit, and calculates and outputs the tilt angle of the objective lens based on the detected light intensity change.
- the principle of calculating the tilt angle will be described with reference to FIGS. 2A to 2C are diagrams showing the relationship between the inclination of the lens holder 16 and the light intensity detected by the detector 26 for detection. In the figure, incident on the upper side The light intensity distribution of the laser light 22 is shown, the state of the inclination of the lens holder 16 is shown at the center, and the detection light receiving position at the detection detector 26 is shown below.
- each detection detector 26 is provided for each reflector 18 and a two-divided photodetector is used as each detection detector 26 is illustrated.
- the photodetector pieces (J, L in FIGS. 2A to C) located on the inner circumference side are referred to as “inner circumference side detectors” and the photodetector pieces located on the outer circumference side ( ⁇ , M) is called “outer-side detector”.
- the lens holder 16 When the lens holder 16 is horizontal (FIG. 2A), the incident laser light incident on the reflector 18 is reflected vertically and received by the detection detector 26.
- the detection detector 26 receives light at a position where the optical axis of the detection reflected light 24 is inclined and shifted toward the inner peripheral side. Therefore, in this case, the amount of light received by the inner detectors J and L is larger than that of the horizontal case, and the amount of light received by the outer detectors ⁇ and M is smaller.
- the lens holder 16 when the lens holder 16 is inclined toward the inner peripheral side (FIG. 2C), the detection reflected light 24 is received at a position shifted toward the outer peripheral side. In other words, the amount of light received by the inner detectors J and L is smaller than that of the horizontal case, and the amount of light received by the outer detectors ⁇ and M is increased.
- the inclination angle of the lens holder 16 is reflected in the change in the amount of light received by each photodetector piece.
- the change in the light intensity detected by each photodetector piece is It can be handled as a change in the amount of received light.
- the computing unit computes and outputs the tilt angle based on the relationship between the tilt angle and the change in the amount of received light.
- the amount of light received by each photodetector piece is not limited to the inclination of the lens holder 16, but also varies depending on the horizontal driving of the lens holder 16 in the radial direction. Therefore, the calculation unit calculates the tilt angle by removing the change in the amount of received light of the reflected light for detection 24 caused by the horizontal driving of the lens holder 16. This will be described with reference to FIGS. 3A to 3C are views showing the relationship between the horizontal driving of the lens holder 16 in the radial direction and the light intensity detected by the detection detector 26 at that time.
- the incident laser light 22 usually has a non-uniform light intensity distribution such as a Gaussian distribution. Therefore, when the lens holder 16 is driven horizontally, the intensity of light applied to the reflector 18 also changes, and consequently, the light intensity of the entire detection reflected light 24 also changes. In other words, a change in the amount of the reflected light for detection 24 caused by horizontal driving can be obtained from the change in the light intensity of the entire reflected light for detection 24.
- the light intensity of the entire reflected light for detection is the sum of the light intensities detected by the inner detectors J and L and the outer detectors ⁇ and M.
- the computing unit can acquire a more accurate inclination angle by adding a correction value based on the light intensity of the entire reflected light for detection 24 from the light intensity detected by each detector piece.
- a specific formula for calculating the tilt angle various forms are conceivable. For example, the following formula can be used.
- J, K, L, and M are light intensity values detected by the respective photodetector pieces, and k is a correction coefficient.
- the horizontal drive amount is detected by means other than the light intensity of each detection reflected light, and a correction value corresponding to the detected horizontal drive amount is added to the light intensity change detected by each photodetector piece. You can do it.
- FIG. 4 shows a block diagram of the overall configuration of the optical disk device 30.
- the optical disk 32 is rotationally driven by a spindle motor (not shown).
- the optical pickup device 34 is arranged to face the optical disc 32, and records or reproduces information by irradiating the surface of the optical disc 32 with a recording / reproducing laser beam.
- recorded data is supplied from the controller 84 to the encoder 82.
- Encoder 82 is supplied The encoded data is encoded and output to the light source drive unit 80.
- the light source drive unit 80 generates a drive signal corresponding to the recording data and drives the light source in the optical pickup device.
- a reproduction signal obtained by the light receiving unit of the optical pickup device 34 is output to the signal processing unit 90, and known RF signal processing, binarization processing, PLL synchronization processing, and the like are executed. .
- a tracking error signal, a focus error signal, an RF signal, etc. are generated. These signals are output to the drive control unit 92.
- the RF signal is output to the decoder 88, demodulated, and then output to the controller 84 as reproduction data.
- the controller 84 outputs the demodulated data from the decoder 88 to a host device such as a personal computer via the input / output interface 86.
- the drive control unit 92 instructs the driving of the lens unit in the optical pickup device 34 so that the tracking error signal and the force error signal of the optical pickup device become zero. Further, the actual tilt angle that is the tilt angle in the radial direction of the current lens unit is also output from the optical pickup device 34 to the drive control unit 92. The drive control unit 92 compares the actual tilt angle with a reference tilt angle stored in the storage unit 94 described later, and instructs the lens unit to drive the tilt so that the difference becomes zero.
- the storage unit 94 stores a reference inclination angle acquired by test irradiation and the like.
- the reference inclination angle is determined based on the reproduction quality when data is reproduced by irradiating the recorded area of the optical disc with test while changing the inclination angle of the lens unit. That is, the inclination angle when the best reproduction quality is obtained is stored as the reference inclination angle.
- the amount of warp of the optical disk 32 varies depending on the inner peripheral force and the outer periphery. Therefore, the reference inclination angle is acquired at a plurality of locations where the radial positions of the optical disk 32 are different.
- the storage unit 94 stores a plurality of reference inclination angles in association with the radial position when each reference inclination angle is acquired! /.
- the reference tilt angle may be obtained by a method other than the test irradiation to the recorded area.
- the reference tilt angle may be obtained using a servo calibration mark (SCM) formed on the recording surface. That is, test irradiation is performed on the optical disk while changing the tilt angle of the lens unit. And the inner circumference during the land trace The side group SCM and the outer side group SCM may be read, and the tilt angle when the two playback output levels are the same may be stored as the reference tilt angle.
- SCM servo calibration mark
- FIG. 5 shows a schematic configuration diagram of the optical pickup device 34.
- Figure 6 shows a side view around the lens unit.
- This optical pickup device 34 is a so-called discrete type in which a light source, a photodetector, a polarizing beam splitter, and the like are separately arranged.
- the optical pickup device 34 includes two types of light sources 36 and 38, and the light emitted from each of the light sources 36 and 38 is an objective lens 41 of the lens unit 40 by a plurality of optical devices such as a combining prism 46. Led to. The light condensed by the objective lens 41 is reflected by the optical disc and received as signal light by a photodetector provided in the light receiving unit 42.
- the lens unit 40 including the object lens 41 and the lens holder 56 is given thrust in the focus direction, tangential direction, and radial direction by an actuator 44 composed of a plurality of electromagnetic coils, and is driven horizontally and vertically. In addition, it is possible to drive tilting in the radial direction.
- the light source includes a blue laser diode (blue LD) 36 that emits laser light in a blue wavelength band, and a dual wavelength laser diode 38 (dual wavelength LD) that emits laser light in a red wavelength band and an infrared wavelength band. Two types are provided.
- the laser light emitted from these light sources 36 and 38 has a non-uniform intensity distribution with a Gaussian distribution. It is emitted as diffused light with a certain spread.
- the optical paths of the laser beams emitted as the incident laser beams from the light sources 36 and 38 are combined by the combining prism 46.
- the combining prism 46 is formed by depositing an optical thin film on the combining surface that reflects light in the blue wavelength band and transmits light in the red wavelength band and infrared wavelength band, and the combining surface is emitted from each of the light sources 36 and 38.
- the incident laser beam is arranged at an angle of 35 degrees with respect to the optical axis of the incident laser beam.
- the incident laser beam transmitted or reflected by the multiplexing prism 46 is collimated by the collimator 48. Further, it is raised vertically by a rising mirror 49 and directed toward the objective lens 41.
- An incident laser beam directed toward the objective lens 41 is provided at the lower part of the lens holder 56 1 After being polarized from linearly polarized light to circularly polarized light by the Z4 wave plate 60, the light enters the objective lens 41.
- the incident laser beam condensed by the objective lens 41 is irradiated onto the recording surface of the optical disc 32, and after recording or reproducing information, it is reflected while being modulated depending on the presence or absence of data.
- the reflected laser light is reflected as signal light to the rising mirror 49 and the combining prism 46, and travels in the reverse optical path substantially the same as the forward path.
- the light is reflected by the polarization beam splitter 50 provided between the blue LD 36 and the combining prism 46 and travels toward the light receiving unit 42.
- the polarization beam splitter 50 reflects or transmits light according to the polarization characteristics.
- the signal light is reflected by the polarization beam splitter 50 through the 1Z4 wavelength plate 60 once in each of the forward path and the return path, and has a polarization direction shifted by 90 degrees with respect to the incident laser light that is P-polarized light. This is the power of S-polarized light.
- the light receiving unit 42 is provided with a plurality of photodetectors for receiving signal light.
- the light intensity of the signal light detected by the photodetector is converted into an electrical signal and output to the signal processing unit 90.
- the light receiving unit 42 is also provided with a detection detector for receiving reflected light for detection described later.
- the lens unit 40 includes an actuator that drives the lens unit 40, an objective lens 41, a lens holder 56 that holds the objective lens 41, and the like.
- the lens unit 40 is cantilevered by the frame 53 via the suspension wire 51. Then, by deforming the suspension wire 53, the lens unit 40 can be driven horizontally, vertically, and tilted.
- the suspension wire 51 is energized to the electromagnetic coil provided in the actuator 44, an electromagnetic force is generated and deformed by an electromagnetic interaction with a magnetic circuit (not shown) fixedly disposed in the vicinity of the frame 53. .
- the actuator 44 includes a force actuator 52 for applying a vertical thrust to the lens unit 40 and a tracking actuator 54 for applying a thrust in the tracking direction.
- the focus actuator 52 is composed of two electromagnetic coil forces provided adjacent to each other in the radial direction. By applying different voltages to the two electromagnetic coils, in other words, the lens unit 40 can be tilted and driven by generating thrusts of different magnitudes in the two electromagnetic coils.
- the objective lens 41 is held by a lens holder 56.
- the lens holder 56 This is composed of a main body 58 and a 1Z4 wavelength plate 60.
- the 1Z4 wave plate 60 polarizes light that passes therethrough, and is provided at a lower portion of the holder main body 58 so as to be inclined in the tangential direction.
- the 1Z4 wavelength plate 60 has a wavelength-selective aperture limiting film (not shown) formed on the bottom surface, and functions as an aperture limiting unit that limits the beam diameter of incident laser light incident on the objective lens 41.
- the wavelength-selective aperture limiting film is an optical thin film that limits transmission according to the wavelength, and is formed on the bottom surface of the 1Z4 wavelength plate 60 so as to have a desired beam diameter for each wavelength.
- the reason for providing such a wavelength-selective aperture limiting film is as follows.
- the light intensity (rim intensity) on the outer peripheral side of the objective lens 41 needs to be a certain level or more.
- an incident laser beam having a diameter larger than the required beam diameter is usually irradiated, and the beam diameter is limited by a wavelength-selective aperture limiting film.
- the reason for changing the beam diameter for each wavelength is to obtain an appropriate NA according to the wavelength of the irradiated laser beam.
- the reflection mirror 62 is provided in the aperture limiting film portion.
- the reflection mirror 62 will be described with reference to FIGS. 7A is a bottom view of the lens unit 40, FIG. 7B is an AA sectional view in FIG. 7A, and FIG. 7C is a BB sectional view in FIG. 7A.
- the reflection mirror 62 reflects a part of incident laser light whose incidence on the objective lens 41 is limited by the wavelength selective aperture limiting film, and has a laminated structure of a 1Z4 wavelength thin film and a reflection film.
- the 1Z4 wavelength thin film is an optical thin film (for example, made of a liquid crystal polymer) that polarizes the light that has passed through the same as the 1Z4 wavelength plate.
- the reflected light reflected by the reflecting mirror 62 becomes S-polarized light having a phase difference of 90 degrees with respect to the incident laser light.
- the reflected light is reflected by the polarization beam splitter 50 and can take almost the same optical path as the signal light.
- Two reflecting mirrors 62 are provided apart from each other in the radial direction.
- the 1Z4 wave plate 60 on which the reflection mirror 62 is formed is inclined, but the part where the reflection mirror 62 is formed has a horizontal reflection surface in a stepped shape as shown in FIG. Many formed
- the laser beam reflected by the reflecting mirror 62 is reflected by the optical disc 32 as reflected light for detection.
- the received signal light is received by a photodetector provided in the light receiving unit 42.
- the optical path of this reflected reflected light for detection is indicated by hatching in FIG.
- FIG. 8A is a view showing an arrangement example of the photodetectors in the light receiving unit 42.
- the photodetector is roughly classified into a signal detector 64 that is a photo detector for detecting signal light and a detection detector 66 that is a photo detector for receiving reflected light for detection.
- the signal detector 64 includes a four-divided photodetector 64a that receives signal light.
- the two-divided photodetectors 64b and 64c are arranged on both sides in the tangential direction of the four-divided photodetector 64a.
- the detection detector 66 includes two two-divided photodetectors 66a and 66b, which are arranged on both sides of the signal detector 64 in the radial direction. Each of the two-divided photodetectors 66a and 66b receives the reflected reflected light for detection reflected by the respective reflecting mirrors 62.
- the light intensity detected by each of the photodetector pieces J, K, L, and M is output to a calculation unit (not shown).
- the computing unit calculates the tilt angle based on the output light intensity. This inclination angle is calculated according to the basic principle described with reference to FIGS. In other words, the tilt angle is output by equation (1).
- photodetectors 66c and 66d that are obliquely divided as shown in FIG. 8B may be used as the detector for detection 66.
- each detector piece can receive light, and thus the tilt angle can be obtained accurately.
- the shape of the photodetector is long in the radial direction, the range in which the detected reflected light can be received can be expanded, and the tilt angle can be acquired more reliably.
- the calculated tilt angle is based on the behavior of the reflected reflected light for detection reflected by the reflecting mirror 62.
- the reflection mirror 62 is driven integrally with the objective lens 41 as apparent from the above description. Therefore, the tilt angle obtained based on the behavior of the reflected reflected light for detection reflected by the reflecting mirror 62 accurately reflects the tilt angle of the objective lens 41! /. Further, since the change in light intensity caused by the horizontal drive is eliminated, an accurate tilt angle can be obtained even when the lens holder 56 is driven horizontally. Therefore, good tilt correction can be achieved by using the tilt angle calculated by this calculation unit as the reference tilt angle or actual tilt angle. It becomes possible. As a result, the recording / reproduction quality of information can be further improved.
- the reflected reflected light for detection is obtained by reflecting the laser light that is not incident on the objective lens among the recording / reproducing laser light (incident laser light). Therefore, it is possible to easily obtain the tilt angle without the need to provide a new light source or the like for detecting the tilt angle. Further, since almost no new members are required, the enlargement of the optical disk device 30 can be prevented.
- FIG. 9 shows a schematic configuration diagram of the hologram type optical pickup device 34.
- the optical pick-up device 34 has a blue hologram unit 68 in which a light source 70 in the blue wavelength band, a polarization beam splitter 76, a photo detector 72, and the like are integrated, and is basically the same as the above-described embodiment.
- the blue hologram unit 68 is a unit in which a blue laser chip 70 that emits a laser beam in a blue wavelength band, a polarizing beam splitter 76, a hologram 74, and a photodetector 72 are unitized.
- the objective lens 56 is provided with the reflection mirror 62 and the detection photo detector for receiving the detection reflected light reflected by the reflection mirror 62. 41 tilt angles can be detected.
- a hologram type optical pickup device can accurately detect an inclination angle, and can further improve the information recording / reproducing quality.
- the entire apparatus can be miniaturized by using the hologram unit.
- FIG. 10 is a schematic bottom view of an optical pickup device 34 according to another embodiment.
- the optical path of the detected reflected light is indicated by hatching, and the optical path of the signal light is indicated by a broken line.
- the reflection surface of the reflection mirror 62 is inclined outward in the radial direction. Therefore, the optical path of the reflected light for detection is in a state where the optical path of the signal light is slightly spread outward.
- crosstalk between the signal light and the reflected light for detection can be prevented, and an accurate inclination angle can be obtained more reliably.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/571,870 US7701814B2 (en) | 2004-07-12 | 2005-05-11 | Optical pickup device and optical disk device |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004-204778 | 2004-07-12 | ||
JP2004204778A JP4093209B2 (ja) | 2004-07-12 | 2004-07-12 | 光ピックアップ装置および光ディスク装置 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2006006296A1 true WO2006006296A1 (ja) | 2006-01-19 |
Family
ID=35783654
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2005/008591 WO2006006296A1 (ja) | 2004-07-12 | 2005-05-11 | 光ピックアップ装置および光ディスク装置 |
Country Status (4)
Country | Link |
---|---|
US (1) | US7701814B2 (ja) |
JP (1) | JP4093209B2 (ja) |
TW (1) | TWI323889B (ja) |
WO (1) | WO2006006296A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2008203818B2 (en) * | 2007-11-27 | 2014-05-01 | Exelis Inc. | Screw actuated night vision goggle tilt mechanism |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4527067B2 (ja) | 2005-03-31 | 2010-08-18 | 株式会社エヌ・ティ・ティ・ドコモ | 移動局、送信方法及び移動通信システム |
JP2009087464A (ja) * | 2007-09-28 | 2009-04-23 | Toshiba Corp | 光ディスク装置およびトラッキング制御方法 |
JP2009104732A (ja) * | 2007-10-25 | 2009-05-14 | Hitachi Maxell Ltd | 光ピックアップレンズ |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS623438A (ja) * | 1985-06-10 | 1987-01-09 | エヌ・ベ−・フイリツプス・フル−イランペンフアブリケン | 光学走査ユニツト |
JPS6352336A (ja) * | 1986-08-21 | 1988-03-05 | Ricoh Co Ltd | 光ピツクアツプ装置 |
JPH0210529A (ja) * | 1988-06-28 | 1990-01-16 | Matsushita Electric Ind Co Ltd | 光ヘッド |
JPH06111350A (ja) * | 1992-09-29 | 1994-04-22 | Matsushita Electric Ind Co Ltd | 光ディスクの傾き検出装置 |
JPH09212901A (ja) * | 1996-01-31 | 1997-08-15 | Matsushita Electric Ind Co Ltd | 光ヘッド |
JP2004164810A (ja) * | 2002-09-19 | 2004-06-10 | Ricoh Co Ltd | 光ディスク装置及びチルト制御量の調整方法 |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2827186B2 (ja) | 1991-08-31 | 1998-11-18 | 日本電気ホームエレクトロニクス株式会社 | 光ディスクの反り検出方法および光ピックアップ |
US5430699A (en) * | 1993-02-24 | 1995-07-04 | Matsushita Electric Industrial Co., Ltd. | Optical reading and writing device |
KR100230250B1 (ko) * | 1994-12-26 | 1999-11-15 | 윤종용 | 광디스크 기울어짐에 의한 수차를 보정하는 방법과 그 장치 |
JP2000057585A (ja) | 1998-08-17 | 2000-02-25 | Nec Corp | 対物レンズの取付位置モニタ装置および対物レンズの取付位置調整方法 |
JP2003132568A (ja) * | 2001-10-25 | 2003-05-09 | Sanyo Electric Co Ltd | 光ディスク装置およびチルト検出方法 |
-
2004
- 2004-07-12 JP JP2004204778A patent/JP4093209B2/ja not_active Expired - Fee Related
-
2005
- 2005-03-03 TW TW094106394A patent/TWI323889B/zh not_active IP Right Cessation
- 2005-05-11 WO PCT/JP2005/008591 patent/WO2006006296A1/ja active Application Filing
- 2005-05-11 US US11/571,870 patent/US7701814B2/en not_active Expired - Fee Related
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS623438A (ja) * | 1985-06-10 | 1987-01-09 | エヌ・ベ−・フイリツプス・フル−イランペンフアブリケン | 光学走査ユニツト |
JPS6352336A (ja) * | 1986-08-21 | 1988-03-05 | Ricoh Co Ltd | 光ピツクアツプ装置 |
JPH0210529A (ja) * | 1988-06-28 | 1990-01-16 | Matsushita Electric Ind Co Ltd | 光ヘッド |
JPH06111350A (ja) * | 1992-09-29 | 1994-04-22 | Matsushita Electric Ind Co Ltd | 光ディスクの傾き検出装置 |
JPH09212901A (ja) * | 1996-01-31 | 1997-08-15 | Matsushita Electric Ind Co Ltd | 光ヘッド |
JP2004164810A (ja) * | 2002-09-19 | 2004-06-10 | Ricoh Co Ltd | 光ディスク装置及びチルト制御量の調整方法 |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2008203818B2 (en) * | 2007-11-27 | 2014-05-01 | Exelis Inc. | Screw actuated night vision goggle tilt mechanism |
Also Published As
Publication number | Publication date |
---|---|
TWI323889B (en) | 2010-04-21 |
JP2006031749A (ja) | 2006-02-02 |
US20070201327A1 (en) | 2007-08-30 |
US7701814B2 (en) | 2010-04-20 |
JP4093209B2 (ja) | 2008-06-04 |
TW200603131A (en) | 2006-01-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP2011096329A (ja) | 光ピックアップ装置 | |
EP1156483B1 (en) | Compatible optical disk player and data recording and reproducing method | |
US6115347A (en) | Optical pick-up device, optical recording/reproducing apparatus and objective lens | |
US8064320B2 (en) | Optical pickup and optical disc apparatus using the same | |
WO2006006296A1 (ja) | 光ピックアップ装置および光ディスク装置 | |
US7898910B2 (en) | Optical pickup apparatus | |
EP1908066A1 (en) | Optical pickup and optical recording and/or re¢ producing apparatus employing the same | |
US7345961B2 (en) | Information medium apparatus and information medium starting method | |
US20090092029A1 (en) | Optical pickup device and information recording/reproduction device | |
KR101041075B1 (ko) | 광픽업 장치 | |
KR100888599B1 (ko) | 광디스크 재생 방법 및 이를 이용한 광디스크 재생 장치 | |
JP3931493B2 (ja) | 光検出器の分割構造およびこの光検出器を用いた光ピックアップ | |
US20050195719A1 (en) | Optical recording medium tilt compensating device, tilt compensating method, and optical recording device and optical reproducing device utilizing the tilt compensating method | |
KR100215455B1 (ko) | 포커스에러를 검출하는 dvd/cd겸용 광픽업시스템 | |
KR100646433B1 (ko) | 광픽업장치 | |
JP5338855B2 (ja) | 光ディスク装置 | |
KR20000066585A (ko) | 광출력모듈 및 이를 채용한 호환형 광픽업장치 | |
KR20130062776A (ko) | 광디스크 장치 및 그 동작 방법 | |
JP2009015947A (ja) | 光ピックアップ装置及びこれを用いた光ディスク装置 | |
JPH1139693A (ja) | 集積光学素子及び光学ピックアップ装置並びに記録再生装置 | |
JP2017054576A (ja) | 光ピックアップ装置および光ディスク装置 | |
JP2004077615A (ja) | プリズム、光ヘッドおよび記録再生装置 | |
JP2009043315A (ja) | 光記録再生装置及び信号検出方法 | |
JP2003303437A (ja) | 光ヘッドおよび記録再生装置 | |
JP2006147014A (ja) | 光ピックアップ |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS KE KG KM KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NG NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SM SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): BW GH GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
DPEN | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed from 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 11571870 Country of ref document: US Ref document number: 2007201327 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: DE |
|
122 | Ep: pct application non-entry in european phase | ||
WWP | Wipo information: published in national office |
Ref document number: 11571870 Country of ref document: US |