KR20090038121A - Apparatus and method for controlling achromatic compensation of optical pickup - Google Patents

Apparatus and method for controlling achromatic compensation of optical pickup Download PDF

Info

Publication number
KR20090038121A
KR20090038121A KR1020070103449A KR20070103449A KR20090038121A KR 20090038121 A KR20090038121 A KR 20090038121A KR 1020070103449 A KR1020070103449 A KR 1020070103449A KR 20070103449 A KR20070103449 A KR 20070103449A KR 20090038121 A KR20090038121 A KR 20090038121A
Authority
KR
South Korea
Prior art keywords
chromatic aberration
mode
recording mode
optical pickup
driving voltage
Prior art date
Application number
KR1020070103449A
Other languages
Korean (ko)
Inventor
이제종
Original Assignee
엘지전자 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 엘지전자 주식회사 filed Critical 엘지전자 주식회사
Priority to KR1020070103449A priority Critical patent/KR20090038121A/en
Publication of KR20090038121A publication Critical patent/KR20090038121A/en

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
    • G02B27/4205—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
    • G02B27/4211—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant correcting chromatic aberrations
    • 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
    • G11B7/1353—Diffractive elements, e.g. holograms or gratings
    • 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
    • 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
    • G11B7/1376—Collimator lenses
    • 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
    • G11B7/1392—Means for controlling the beam wavefront, e.g. for correction of aberration

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Head (AREA)

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for controlling chromatic aberration of optical pickup, for example, in an optical pickup for a Blu-ray disc equipped with an achromatic correction element, from reproduction mode to recording mode. When switching is performed, the chromatic aberration correction operation is performed to prevent the wavelength of the blue laser beam from being shifted, and to automatically change the driving voltage applied to the chromatic aberration correction element when switching from the recording mode to the reproduction mode. By blocking, the diffraction noise component is prevented from entering the Servo signal such as the sub-push pull signal, so that the chromatic aberration component can be corrected in the recording mode. In this case, the servo error due to the inflow of diffraction noise can be prevented in advance.

Description

Apparatus and method for controlling achromatic compensation of optical pickup}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for controlling chromatic aberration of optical pickup. For example, in an optical pickup for a Blu-ray disc equipped with an achromatic correction element, a chromatic aberration correction operation may be selectively performed. The present invention relates to a chromatic aberration correction control apparatus and method for optical pickup.

Due to the high density trend of optical recording technology, optical pickups are using laser diodes with shorter wavelengths and objective lenses with larger numerical apertures (NA), for example for Blu-ray discs. For optical pickup, a blue laser diode with a wavelength of 405 nm and an objective lens with 0.85 numerical aperture (NA) are used.

Meanwhile, FIG. 1 illustrates an exemplary optical pickup for a Blu-ray Disc. For example, the Blu-ray Disc optical pickup includes, for example, a laser diode 10, a beam splitter 11, and a collimator lens 12. ), A chromatic aberration correcting element 13, an objective lens 14, a photo detector 15 and the like.

In addition, the laser diode 10 emits a blue laser beam having a wavelength of 405 nm, and the blue laser beam passes through the beam splitter 11 to form a collimator lens 12. After being incident on the light source, the collimator lens 12 converts the diffused light into parallel light.

The blue laser beam converted into the parallel light passes through the chromatic aberration correcting element 13 and the objective lens 14, and is focused on a recording layer of an optical disc such as a Blu-ray disc 20 to emit a beam spot. Since the chromatic aberration correcting element 13 corrects chromatic aberration by using a diffraction pattern (Pattern), the change in the wavelength of the blue laser beam when switching from the data reproduction mode to the recording mode This will prevent defocus.

2 illustrates an embodiment in which the laser wavelength is shifted by a general chromatic aberration correcting element. The read power (Pr) of the laser diode 10 for data reproduction is used as 0.4 mW, and When using the write power (Pw: Write Power) of the laser diode 10 for data recording at 5 mW, assuming that the optical efficiency to the objective lens 14 is 10%, Between the wavelength of the blue laser beam (e.g., 404 nm) and the wavelength of the blue laser beam (e.g., 404.5 nm) at the time of the light power, a shift occurs by about 0.5 nm, resulting in a defocus state.

When the Blu-ray disc 20 is a dual layer disc having two recording layers, the lead power Pr of the laser diode 10 for data reproduction is 0.8 mW. Since the light power Pw of the laser diode 10 for data recording is used at 10 mW, between the wavelength of the blue laser beam at the read power and the wavelength of the blue laser beam at the light power, A shift occurs by 1.0 nm, resulting in a defocus state.

3 illustrates an embodiment in which the laser wavelength is shifted in the recording mode when the general chromatic aberration correction element is not used, and FIG. 4 illustrates an embodiment in which the laser wavelength is not shifted in the recording mode when the general chromatic aberration correction element is used.

For example, as shown in Fig. 3, when the chromatic aberration correcting element 13 is not used, the defocus is about 0.09 um at 0.04 ms, which is a timing for switching from the playback mode to the recording mode. This is caused by the laser wavelength shift. Typically, the focus actuator has a limited bandwidth of 5 kHz, which makes it relatively impossible to prevent defocus.

That is, as shown in Fig. 5, when switching from the reproduction mode to the recording mode, the change in defocus causes a decrease in the RF modulation signal, and therefore, the jitter / error rate The chromatic aberration correcting element must be provided essentially.

However, such a chromatic aberration correcting element corrects chromatic aberration by using a diffraction pattern, and thus affects a servo signal due to a noise component due to diffraction.

For example, as shown in FIG. 6, when a chromatic aberration correction element is used, a main push pull (MPP) signal, a sub push pull (SPP) signal, and a differential push pull (SPP) signal are used. DPP: Differential Push Pull (DPP) signal has a problem that diffraction noise component affects, especially the sub push-pull (SPP) signal that uses a small amount of light, which causes a problem in servo control operation. .

In the optical pickup for a Blu-ray disc equipped with an achromatic correction element, the present invention performs a chromatic aberration correction operation when switching from a reproduction mode to a recording mode, whereby the wavelength of the blue laser beam is increased. In addition to preventing shifting, a servo signal such as a sub-push-pull (SPP) signal is automatically cut off by automatically blocking a driving voltage applied to the chromatic aberration correction element when switching from recording mode to reproduction mode. SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and method for correcting chromatic aberration of optical pickup for preventing the introduction of diffraction noise components into the optical pickup.

In order to achieve the above object, an apparatus for correcting chromatic aberration of an optical pickup according to the present invention includes a collimator lens for converting a diffuse light laser beam into a parallel light laser beam; A chromatic aberration correcting element for correcting chromatic aberration of the parallel light laser beam; An objective lens for focusing the chromatic aberration-corrected parallel light laser beam on the recording layer of the optical disk as a beam spot; And control means for blocking the driving voltage applied to the chromatic aberration correcting element when switching from the recording mode to the reproduction mode,

The control means is a servo controller which operates and controls an actuator driver to cut off a driving voltage applied to the chromatic aberration correcting element from a recording mode to a reproducing mode, wherein the servo controller records in the reproducing mode. In operation mode, the actuator driver is controlled to apply a driving voltage to the chromatic aberration correction element.

In addition, the chromatic aberration correcting element removes the chromatic aberration component by using a diffraction pattern, the optical disk is a Blu-ray disc, and the chromatic aberration correcting element is provided at the front end of the objective lens, or It is characterized in that it is installed on the front end of the collimator lens,

In addition, the chromatic aberration correction control method of the optical pickup according to the present invention, the first step of determining whether the operation mode of the optical pickup including the chromatic aberration correction element is switched from the recording mode to the reproduction mode; And a step of interrupting a driving voltage applied to the chromatic aberration correcting element when switching from the recording mode to the reproduction mode as a result of the determination,

Further, as a result of the determination, if it is not switched from the recording mode to the reproduction mode, the step of maintaining the driving voltage applied to the chromatic aberration correction element, and after the step 2, the operation mode of the optical pickup is recorded in the reproduction mode When switching to the mode, characterized in that it further comprises the step of applying a driving voltage to the chromatic aberration correction element,

In the second step, when the switching result is changed from the recording mode to the reproduction mode, the servo controller operates to control the actuator driver to cut off the driving voltage applied to the chromatic aberration correcting element. The chromatic aberration component is removed using a diffraction pattern, and is provided at the front end of the objective lens or at the front end of the collimator lens.

According to the present invention, in the optical pickup for a Blu-ray disc equipped with an achromatic correction element, the chromatic aberration correction operation is performed when switching from the reproduction mode to the recording mode, so that the wavelength of the blue laser beam is increased. It is possible to prevent the shift and also to automatically cut off the driving voltage applied to the chromatic aberration correcting element when switching from the recording mode to the reproduction mode, such as a servo such as a sub push-pull (SPP) signal. By preventing the diffraction noise component from being introduced into the signal, it is possible to effectively prevent the servo error due to the inflow of the diffraction noise.

Hereinafter, a preferred embodiment of an apparatus and method for correcting chromatic aberration of an optical pickup according to the present invention will be described with reference to the accompanying drawings.

The apparatus and method for controlling chromatic aberration correction according to the present invention can be applied to various types of optical pickups such as optical pickups for Blu-ray discs equipped with chromatic aberration correction elements for removing achromatic components by using a diffraction pattern. Can be applied.

Meanwhile, FIG. 7 illustrates an embodiment of an optical pickup to which the apparatus and method for correcting chromatic aberration according to the present invention is applied. For example, a blue laser beam having a wavelength of 405 nm and an objective lens having a 0.85 NA numerical aperture are used. The optical pickup for the Blu-ray Disc includes a laser diode 10, a beam splitter 11, a collimator lens 12, a chromatic aberration correcting element 13, an objective lens 14, a photo detector 15, and a servo controller 16. ) And an actuator driver 17 are included.

The laser diode 10 emits, for example, a blue laser beam having a wavelength of 405 nm. The blue laser beam is incident to the collimator lens 12 through the beam splitter 11.

In the collimator lens 12, when the blue laser beam of diffused light incident through the beam splitter 11 is converted into a blue laser beam of parallel light, the blue laser beam of the parallel light is the chromatic aberration correcting element ( 13) and the objective lens 14, beam spots are formed in the recording layer of the optical disk, such as a Blu-ray disk 20. FIG.

In addition, the chromatic aberration correcting element 13 removes the chromatic aberration component of the blue laser beam incident through the collimator lens 12 using a diffraction pattern, thereby referring to FIGS. 2 to 5. As described above, when switching from the reproduction mode to the recording mode, the wavelength of the blue laser beam is shifted to prevent defocus from being generated. For example, as shown in FIG. The chromatic aberration correcting element 13 may be provided at the front end of the objective lens 14 or at the front end of the collimator lens 13.

Meanwhile, the chromatic aberration correcting element 13 may use various types of optical elements, such as LCDs, which are turned on and off by a driving voltage applied from the actuator driver 17. The actuator driver 17 is operation controlled by the servo controller 16 which separately controls the servo operation in the recording mode and the servo operation in the regeneration mode.

In the servo controller 16, for example, when switching from a data reproducing mode to a recording mode according to a user's request, the servo controller 16 interworks with a write control signal output from a microcomputer (not shown). By operating the actuator driver 17, the actuator driver 17 applies a driving voltage to the chromatic aberration correcting element 13 by a control signal of the servo controller 16.

On the other hand, in the servo controller 16, for example, when switching from a data recording mode to a read mode according to a user's request, a read control signal output from a microcomputer (not shown) is applied. In operation, the actuator driver 17 is controlled to operate. The actuator driver 17 cuts off a driving voltage applied to the chromatic aberration correcting element 13 by a control signal of the servo controller 16. Done.

As a result, the chromatic aberration correcting element 13 stops the chromatic aberration correcting operation of removing the chromatic aberration component using a diffraction pattern, so that the chromatic aberration correcting element 13 changes the recording mode to the reproduction mode. Diffraction Noise can be prevented from occurring.

Therefore, when the recording operation is performed in the optical pickup for the Blu-ray disc to which the present invention is applied, for example, as described above with reference to FIG. 2, when switching to the recording mode using 5 mW of light power Pw. By performing chromatic aberration correction operation, the wavelength of the laser beam is prevented from being shifted, thereby preventing defocus error.

When the reproduction operation is performed in the optical pickup for the Blu-ray disc, for example, when switching to the reproduction mode using the 0.4 mW read power Pr, the chromatic aberration correction operation is stopped to thereby use the sub-light. By preventing diffraction noise from flowing into a servo signal such as a push pull (SPP) signal, a stable servo control operation can be performed.

The above-described preferred embodiment of the present invention has been disclosed for the purpose of illustration, and the optical pickup for the Blu-ray disc equipped with the chromatic aberration correction element, in addition to the optical element shown in FIG. Devices may be included, and also those skilled in the art will be able to improve, change, substitute, or add other various embodiments within the spirit and scope of the present invention.

1 shows an embodiment of an optical pickup for a general Blu-ray disc,

2 illustrates an embodiment in which the laser wavelength is shifted by a general chromatic aberration correction element,

3 illustrates an embodiment in which a laser wavelength is shifted in a recording mode when a general chromatic aberration correcting element is not used.

4 illustrates an embodiment in which the laser wavelength is not shifted in the recording mode when a general chromatic aberration correction element is used.

FIG. 5 illustrates an embodiment in which an RF modulated signal is reduced when a general chromatic aberration correcting element is not used.

FIG. 6 illustrates an embodiment in which a sub push-pull signal is unstable in a reproduction mode when a general chromatic aberration correction element is used.

7 illustrates an embodiment of an optical pickup for a Blu-ray disc to which the present invention is applied.

8 illustrates an embodiment in which the sub-push-pull signal is stably output by turning off the chromatic aberration correction operation in the reproduction mode according to the present invention.

※ Explanation of code for main part of drawing

10 laser diode 11: beam splitter

12 collimator lens 13 chromatic aberration correction element

14: objective 15: photo detector

16: Servo Controller 17: Actuator Driver

20: Blu-ray Disc

Claims (10)

A collimator lens for converting the diffuse light laser beam into a parallel light laser beam; A chromatic aberration correcting element for correcting chromatic aberration of the parallel light laser beam; An objective lens for focusing the chromatic aberration-corrected parallel light laser beam on the recording layer of the optical disk as a beam spot; And And a control means for cutting off the driving voltage applied to the chromatic aberration correcting element from the recording mode to the reproducing mode. The method of claim 1, The control means is a chromatic aberration correction control device for optical pickup, characterized in that for controlling the operation of the actuator driver to cut off the driving voltage applied to the chromatic aberration correction element from the recording mode to the reproduction mode. The method of claim 2, And the servo controller controls the actuator driver to apply a driving voltage to the chromatic aberration correcting element when switching from a reproducing mode to a recording mode. The method of claim 1, And the chromatic aberration correction element removes the chromatic aberration component by using a diffraction pattern, and the optical disc is a Blu-ray disc. The method of claim 1, The chromatic aberration correcting control device of the optical pickup, wherein the chromatic aberration correcting element is provided at the front end of the objective lens or at the front end of the collimator lens. A first step of determining whether the operation mode of the optical pickup including the chromatic aberration correction element is switched from the recording mode to the reproduction mode; And And a step (2) of shutting off the driving voltage applied to the chromatic aberration correcting element when switching from the recording mode to the reproduction mode as a result of the determination. The method of claim 6, And maintaining the driving voltage applied to the chromatic aberration correcting element when it is not switched from the recording mode to the reproducing mode as a result of the determination. The method of claim 6, And after the step 2, when the operation mode of the optical pickup is switched from the reproduction mode to the recording mode, applying a driving voltage to the chromatic aberration correction element. . The method of claim 6, In the second step, when the switching from the recording mode to the reproduction mode results in the determination, the servo controller operates the actuator driver to cut off the driving voltage applied to the chromatic aberration correcting element. Calibration control method. The method of claim 6, The chromatic aberration correcting element removes the chromatic aberration component by using a diffraction pattern, and is provided at the front end of the objective lens or at the front end of the collimator lens. Chromatic aberration correction control method.
KR1020070103449A 2007-10-15 2007-10-15 Apparatus and method for controlling achromatic compensation of optical pickup KR20090038121A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020070103449A KR20090038121A (en) 2007-10-15 2007-10-15 Apparatus and method for controlling achromatic compensation of optical pickup

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020070103449A KR20090038121A (en) 2007-10-15 2007-10-15 Apparatus and method for controlling achromatic compensation of optical pickup

Publications (1)

Publication Number Publication Date
KR20090038121A true KR20090038121A (en) 2009-04-20

Family

ID=40762415

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020070103449A KR20090038121A (en) 2007-10-15 2007-10-15 Apparatus and method for controlling achromatic compensation of optical pickup

Country Status (1)

Country Link
KR (1) KR20090038121A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190006456A (en) * 2017-07-10 2019-01-18 칼 짜이스 에스엠티 게엠베하 Inspection device for masks for semiconductor lithography and method
US10848835B2 (en) 2017-11-23 2020-11-24 Plain Bagel, Inc. Video summary information playback device and method and video summary information providing server and method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190006456A (en) * 2017-07-10 2019-01-18 칼 짜이스 에스엠티 게엠베하 Inspection device for masks for semiconductor lithography and method
US10928332B2 (en) 2017-07-10 2021-02-23 Carl Zeiss Smt Gmbh Inspection device for masks for semiconductor lithography and method
KR20210087911A (en) * 2017-07-10 2021-07-13 칼 짜이스 에스엠티 게엠베하 Impact of scanner-axial-chromatic aberation on aerial image
US11867642B2 (en) 2017-07-10 2024-01-09 Carl Zeiss Smt Gmbh Inspection device for masks for semiconductor lithography and method
US10848835B2 (en) 2017-11-23 2020-11-24 Plain Bagel, Inc. Video summary information playback device and method and video summary information providing server and method

Similar Documents

Publication Publication Date Title
JPH1064097A (en) Optical pickup device
US20060187786A1 (en) Optical information recording and reproducing apparatus
US7542397B2 (en) Aberration correction apparatus, and control apparatus, control method and control program of optical pickup
US20110080817A1 (en) Compatible optical pickup and optical information storage medium system employing the same
JP2007157288A (en) Optical pickup
KR20090038121A (en) Apparatus and method for controlling achromatic compensation of optical pickup
JP3619371B2 (en) Optical pickup device and tilt detection method thereof
KR100783452B1 (en) Optical disc recording/reproducing apparatus
US20090003182A1 (en) Optical disc apparatus with optical head unit
JP2009223946A (en) Optical pickup apparatus
JP4499688B2 (en) Optical information processing equipment
JP2008090923A (en) Laser diode driver and optical pickup for dealing with n wavelengths equipped therewith
JP4345572B2 (en) Optical pickup and recording / reproducing apparatus using the same
JP5380331B2 (en) Optical disc, optical disc apparatus and reproducing method
US6388966B2 (en) Optical information recording and reproducing apparatus
JPH1173677A (en) Optical disk device
KR20080082387A (en) Method for reproducing optical disc and optical reproducing apparatus using the same
US20080205212A1 (en) Optical head apparatus, information recording/reproducing apparatus including the optical head apparatus, and information recording/reproducing method
JP2006286079A (en) Optical head and optical disk device
JP2008071445A (en) Optical recording/reproducing device and optical pickup
JP4340689B2 (en) Optical pickup and information recording / reproducing apparatus
JP2014032720A (en) Optical disk device
JP2007226848A (en) Optical pickup device, and information recording and/or reproducing device
JP2005293658A (en) Optical pickup and optical disk apparatus
US20110044142A1 (en) Optical disc apparatus and optical disc reproducing method

Legal Events

Date Code Title Description
WITN Withdrawal due to no request for examination