CN1220454A - Dual focusing optical pickup device - Google Patents

Dual focusing optical pickup device Download PDF

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Publication number
CN1220454A
CN1220454A CN98125330A CN98125330A CN1220454A CN 1220454 A CN1220454 A CN 1220454A CN 98125330 A CN98125330 A CN 98125330A CN 98125330 A CN98125330 A CN 98125330A CN 1220454 A CN1220454 A CN 1220454A
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CN
China
Prior art keywords
wave plate
quarter
transmission
piece
type optics
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Pending
Application number
CN98125330A
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Chinese (zh)
Inventor
催良吾
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WiniaDaewoo Co Ltd
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Daewoo Electronics Co Ltd
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 Daewoo Electronics Co Ltd filed Critical Daewoo Electronics Co Ltd
Publication of CN1220454A publication Critical patent/CN1220454A/en
Pending legal-status Critical Current

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    • 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
    • G11B7/139—Numerical aperture control means
    • 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
    • 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
    • G11B7/12—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
    • G11B7/1365—Separate or integrated refractive elements, e.g. wave plates
    • 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

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Head (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

A dual focusing optical head device has a integrated optical component of square shape, whose diagonal plane forms a polarization beam splitting component. The P polarized light beam emited from the laser source transmits the polarization beam splitting component, passing through a transmission quarter-wave plate and selective optical transmission plate on the integrated optical component, and focused on the CD by the object lens. The beam totally transmits the inner round of the selective optical transmission plate, and semi-transmits the circumference part of the selective optical transmission plate. The beam transmits the circular optical transmission plate and the quarter-wave plate, and changed ino the S polarized light. The beam are reflected by the polarization beam splitting film and changed into the P polarized light by the quarter-wave plate, then reflected by the reflective film. The beam is tested by the optical receiver.

Description

Dual focusing optical pickup device
The present invention relates to a kind of optic probe device, dual focusing optical pickup device particularly, this device can be by the reset dish of two kinds of different densities of the twin-beam focus of different size, and wherein two kinds of different optical elements are all integrally made, so that make this equipment miniaturization and simplification.
Developed the information playback/register system of multiple employing CD or mini disk in recent years.This information playback/register system various information of resetting/write down.The reset digital video disk machine of image of the digital disc record machine and being used to of music of being used to reset is exactly the example of this respect.Present trend is that the density of recording medium of these optical information playback/register systems is higher so that make dish finer and close and small and exquisite, and the disc player of these optical information playback/register systems is compacter and more miniaturization.In addition, but developing a kind of compatible system, such as the record of high-definition television (HDTV) that can compatible optic disk.
At United States Patent (USP) NO.4, the structure and the operation of ordinary optical head unit are disclosed in 767,921 or 4,868,377.
Describe traditional ordinary optical head unit in detail below with reference to Fig. 1.
Fig. 1 is the synoptic diagram of traditional ordinary optical head unit.In Fig. 1, label 11 expressions produce the light source of laser beam, and promptly laser diode 11.Diffraction takes place in the laser beam of sending from laser diode 11 by diffraction grating 12 time.Diffracted beam directive beam splitter 13.
Herein, beam splitter 13 forms in the following manner: two right angle prisms are provided with relatively with the inclined-plane of separately 45, form coating 13a along the contact portion of two prisms, transmission part incident beam and reflect another part incident beam and make it when having the straight line transport property perpendicular to incident beam.
Diffracted beam reflects to CD 15 by beam splitter 13.Focus on the record plane 15a of CD 15 by the object lens 14 that are arranged on such as the recording medium front of CD 15 from beam splitter 13 beam reflected.The image of the light beam of receiving from optical receiver 16 can be checked the site error of optic probe device with respect to CD 15, and promptly therefore focusing error and tracking error focus on and follow the tracks of and can control.In addition, just can sense information according to the quantity of the definite folded light beam in the recessed road on the record plane 15a of CD 15.
Simultaneously, in above-mentioned traditional optical head unit,, be difficult to make and control this optic probe device owing to all be manufacturing separately and be positioned at respectively on the accurate separately position such as optical elements such as beam splitter, diffraction grating, laser diode and optical receivers.In addition, essential compactness of optic probe device and CD player and miniaturization could be satisfied the development trend of present CD player.
In addition, according to this traditional optic probe device, can not or write down two kinds of different dishes with an optic probe device playback.For example, if compare with digital disc record, the registering capacity of similar digital video disk is its four times, and then the width of Pan Zhongaodao will reduce 1/2.For this reason, be half of focal beam spot on the digital disc record at the focal beam spot on the digital video disk, thereby if adopt traditional optic probe device just to need different optic probe devices reset digital video disk and digital disc record.That is to say, in order to read the data that are recorded in respectively on digital video disk and the digital disc record exactly, need to adopt the optic probe device of the digital disc record of a kind of correspondence, its hot spot is of a size of 1.6 μ m when light beam focuses on the digital disc record, and corresponding digital video disk adopts another kind of optic probe device, and its hot spot is of a size of 0.8 μ m when light beam focuses on the digital video disk.
Therefore, the object of the present invention is to provide a kind of optic probe device, wherein different optical elements are all made integratedly, so that make this equipment miniaturization and simplification.
Another object of the present invention is to provide a kind of optic probe device, can be by the twin-beam focuses that form different sizes two kinds of the dishes of resetting with different densities.
For realizing above-mentioned purpose of the present invention, optic probe device comprises: lasing light emitter is used to produce laser beam with predetermined polarisation direction and the information of playback CD;
One-piece type optics, make laser beam towards the CD transmission and focus on the laser beam of returning by CD with predetermined polarisation direction, one-piece type optics has polarization beam splitting spare, the transmission quarter-wave plate, the reflection quarter-wave plate, light receiving piece, wherein, polarization beam splitting spare forms on the diagonal plane of one-piece type optics, be used for making laser beam also reflect the laser beam of returning from CD according to the polarization direction subsequently towards the CD transmission with predetermined polarisation direction according to the polarization direction, the transmission quarter-wave plate forms at the first surface in the face of CD of this one-piece type optics, be used for after light beam is by the beam splitting part, changing the polarization direction that turns back to the light beam of beam splitting part by dish, the reflection quarter-wave plate forms on the second surface of this one-piece type optics reception by beam splitting part beam reflected, be used to reflect by beam splitting part beam reflected and change the polarization direction of folded light beam, light receiving piece forms on the 3rd surface relative with the reflection quarter-wave plate, is used for detecting by reflection quarter-wave plate beam reflected;
The selective light transmissive piece, be arranged between one-piece type optics and the CD, be used for will be by beam splitter light beam towards the CD transmission, the selective light transmissive piece has inner circular part and divides and circumferential section, the inner circular part branch is used for the first transmissivity transmission laser bundle, and circumferential section is used for the second transmissivity transmission laser bundle; And
Object lens are arranged between one-piece type optics and the CD, are used to make laser beam to focus on CD by one-piece type optics.
The Fresnel lens are arranged on the reflection quarter-wave plate, are used to shorten the light path of laser beam.
Diffraction grating is arranged on the reflection quarter-wave plate, is used for the laser beam of diffraction tracking servo and focus servo.
The selective light transmissive piece has inner circular part divides and circumferential section, and the inner circular part branch is used for the first transmissivity transmission laser bundle, and circumferential section is used for the second transmissivity transmission laser bundle.First transmissivity is greater than second transmissivity.Preferably, inner circular part is divided into total transmissivity, its transmissivity is 1, and circumferential section is a half transmitting, and transmissivity is 1/2.
The selective light transmissive piece forms at the first surface that one-piece type optics forms the transmission quarter-wave plate.
Divide the exterior angle of the incident beam of transmission can adjust the difference that focuses on the spot size on the CD by suitably adjusting from the inner circular part of selective light transmissive piece.
According to dual focusing optical pickup device of the present invention as mentioned above, owing to make integratedly and in manufacture process, be fixed on the accurate separately position such as optical elements such as beam splitter, diffraction grating and optical receivers,, it is very simple that the manufacturing of this optic probe device and control become.
In addition, shorten light path by adopting such as the such optical element of Fresnel lens, optic probe device can very compact and miniaturization.
According to aforesaid dual focusing optical pickup device of the present invention, when laser beam is passed through the selective light transmissive piece, divide the laser beam of transmission on CD, to form less hot spot by inner circular part in the laser beam that the bigger hot spot of formation on the CD passes through the circumferential section transmission.Therefore, formed the twin-beam focus of different sizes by adopting an optic probe device, thus can be by the dish of two kinds of different densities of an optic probe device playback.
Therefore, for digital disc record and digital video disk, adopt optic probe device of the present invention all can reset with different registering capacities.
Describe the preferred embodiment of the present invention in detail by the reference accompanying drawing, above-mentioned purpose of the present invention and other advantage will become clearer, wherein:
Fig. 1 is the synoptic diagram of traditional optical head unit;
Fig. 2 is the synoptic diagram of dual focusing optical pickup device of the present invention;
Fig. 3 illustrates the light path of dividing the laser beam of transmission by the inner circular part of the selective light transmissive piece of dual focusing optical pickup device among Fig. 2;
Fig. 4 illustrates the light path by the laser beam of the excircle part transmission of the selective light transmissive piece of dual focusing optical pickup device among Fig. 2.
Describe optic probe device of the present invention below with reference to accompanying drawings in detail.
Fig. 2 is the synoptic diagram of dual focusing optical pickup device of the present invention.
As shown in Figure 2, in this embodiment, laser diode 100 sends the P polarized laser beam, in order to the be placed on it information of CD of portion of playback.
Cuboidal one-piece type optics 200 is parallel to the surface of CD and is arranged under the CD, has the laser beam of predetermined polarisation direction and focuses on the laser beam of returning from CD towards the CD transmission.
One-piece type optics 200 is a block prism.This prism has predetermined refractive index and the light path of the light beam of transmission is shortened.
One-piece type optics 200 is used for also focusing on the laser beam of returning from CD towards digital video disk 160 or digital disc record 170 transmissions far away slightly from the P light beam that laser diode 100 sends.
That is to say that polarizing beam splitting film 220 forms on the diagonal plane of 45 ° of the inclinations of square prism 200.Polarizing beam splitting film 220 is the 100 P polarized laser beam of sending towards the CD transmission from laser diode.
Transmission quarter-wave plate 225 forms at the first surface of one-piece type optics 200, and first surface is the upper surface of one-piece type optics 200 and faces CD, is used to change the polarization direction of light beam.After transmission quarter-wave plate 225 is crossed in the P light beam transmission of polarizing beam splitting film 220 transmissions, light beam returns the transmission quarter-wave plate.Through 225 transmissions of transmission quarter-wave plate the time, light beam becomes the S light beam.
Reflection quarter-wave plate 260 on second surface, i.e. the surface of the one-piece type optics 200 that meets at right angle with beam splitting coating 220 beam reflected.The reflection quarter-wave plate has the interior quarter-wave plate 265 and the external reflection film 263 that is used for by beam splitting coating 220 beam reflected that is used to change the light beam polarization direction.
The Fresnel lens are arranged on the reflection quarter-wave plate 260, are used to shorten the light path of laser beam.
Diffraction grating 230 is arranged on the reflection quarter-wave plate 260, and diffraction is used for the laser beam of tracking servo and focus servo.
Holographic apparatus can be set replace diffraction grating 230.
Optical receiver 240 is arranged on the 3rd surface relative with reflecting quarter-wave plate 260, is used for detecting by reflection quarter-wave plate 260 beam reflected.
Selective light transmissive piece 250 is formed on the upper surface of one-piece type optics 200.Selective light transmissive piece 250 is arranged on the top of one-piece type optics 200.
Selective light transmissive piece 250 has inner circular part and divides 251 and circumferential section 252, and inner circular part divides 251 to be used for the first transmissivity transmission laser bundle, and circumferential section 252 is used for the second transmissivity transmission laser bundle.First transmissivity is greater than second transmissivity.Preferably, inner circular part divides 251 for total transmissivity, its transmissivity is 1, and circumferential section 252 is a half transmitting, and transmissivity is 1/2.
Object lens 110 CD 160 or 170 and the selective light transmissive piece 250 that forms on the upper surface of one-piece type optics 200 or top between so that will focus on by the light beam of transmittance part 250 on the record plane 165 of CD 160.Object lens 110 are that non-spherical lens is to reduce spherical aberration.Object lens 110 are preferably the lens that are used for DVD, thereby make through the light beam of the circumferential section transmission of the selective light transmissive piece 250 thick digital video disk of 0.6mm (DVD) of can resetting.
The operation of previous embodiment will be described below.
The P polarized laser beam penetrates towards one-piece type optics 200 from laser diode 100.
The P polarized laser beam incides on the polarizing beam splitting film 220 of one-piece type optics 200 with 45.The light beam total transmissivity is directly upwards propagated by polarizing beam splitting film.
Quarter-wave plate 225 and selective light transmissive piece 250 that the P light beam forms by the upper surface at one-piece type optics 200.The light beam total transmissivity divides 251 by the inner circular part of selective light transmissive piece 250, and half transmitting is by the circumferential section 252 of selective light transmissive piece 250.
Transmitted light beam focuses on the record plane 165 of CD 160 by the DVD object lens 110 that are arranged between CD 160 and the one-piece type optics 200.
At this moment, the inner circular part of total transmissivity by circular light transmissive piece 250 divide 251 laser beam by object lens 110 with θ 1 angular focusing on CD 160.Simultaneously, the laser beam of the circumferential section 252 of half transmitting by circular light transmissive piece 250 by object lens 110 with θ 2 angular focusing on CD 160.
The recessed road of record that is coiled on 160 with the laser beam of θ 1, θ 2 angular focusing reflects.Folded light beam is returned one-piece type optics 200 by object lens 11O.The light beam transmission of returning is by transmittance part 250 and quarter-wave plate 225.
Light beam changes the S light beam into.Light beam after the transformation is reflected by the polarizing beam splitting film 220 with optical path direction inclination 45.
The light beam that has optical information is by polarizing beam splitting film 220 reflections, and changes the P polarized light into by interior quarter-wave plate 265 subsequently and by external reflection film 263 reflections of the polarization direction that is used to change light beam.
If on the reflection quarter-wave plate Fresnel lens are set, light beam can be focused on sharp.
The 3rd lip-deep optical receiver 240 that is arranged on the one-piece type optics 200 relative with reflecting quarter-wave plate is received folded light beam.
At this moment, the inner circular part by circular light transmissive piece 250 divides 251 to produce two kinds of different numerical apertures (N.A.) with circumferential section 252.By these two kinds of different numerical apertures, on CD 160, form the hot spot of two kinds of different sizes.Therefore, difference appears in light quantity.
That is to say NA.1=η sin θ 1 and N.A.2=η sin θ 2 (wherein η represents the refractive index of medium, and θ is the angle that forms between optical axis and the outermost incident beam).
At this moment, the diameter W of light beam 0Be expressed as:
W 0=K *λ/N.A. (wherein K is a constant)
D 0(depth of focus)=R *λ/(N.A.) 2(wherein R is a constant).
Therefore, along with the variation of numerical aperture, the size of light beam and the degree of depth of focus also change.
Therefore, be that the size and the depth of focus of the light beam that focuses on of θ 1 is little after the circumferential section by circular light transmissive piece 250 252 being the size of the light beam that focuses on of θ 2 and the depth of focus than dividing by inner circular part after 251 with outermost incident angle with outermost incident angle.This is because size and the N.A. of light beam is inversely proportional to, and the degree of depth of focus and (N.A.) 2Be inversely proportional to.
When CD 160 is the digital video disk of 0.6mm for thickness, by 250 transmissions of transmittance part after object lens focusing forms size at the light beam on the CD on CD 160 be the hot spot of 0.8 μ m.Because these object lens are the DVD lens, light beam can focus on the record plane of digital video disk exactly and can not produce spherical aberration.
Simultaneously, when CD 160 is the digital disc record of 1.2mm for thickness, since on optical axis and near optical axis the inner circular part of light beam total transmissivity by circular light transmissive piece 250 divide 251, at the light beam half transmitting at the optical axis edge circumferential section 252 by circular light transmissive piece 250, the numerical aperture N.A. that focuses on the light beam on the CD by object lens 110 diminishes and is N.A.1.Therefore, compare spherical aberration that the thickness difference of 0.6mm causes with digital video disk because the numerical aperture that reduces and obviously reducing.The digital disc record of recessed road broad so can reset.
That is to say, when resetting digital disc record, owing to the thickness difference of comparing 0.6mm with digital video disk produces spherical aberration.
At this moment, spherical aberration is
(Δd/8) *{(η 2-1)η 3} *(N.A.) 4
(wherein Δ d is the thickness difference of dish, and η is the refractive index of medium, and N.A. is a numerical aperture)
What therefore, have a less spherical aberration divides 251 on optical axis and near the light beam total transmissivity of the optical axis inner circular part by circular light transmissive piece 250.In addition, the light beam at scioptics edge has bigger spherical aberration and the half transmitting circumferential section 252 by circular light transmissive piece 250.Therefore, the numerical aperture that forms of light beam diminishes and is N.A.1=η sin θ 1.Therefore, with (N.A.) 4The spherical aberration that is directly proportional sharply reduces.In addition, because numerical aperture diminishes and be N.A.1=η sin θ 1, the spot size that is inversely proportional to (N.A.) that forms on dish is greatly to 1.6 μ m.Therefore, can the reset digital disc record of recessed road broad.
According to dual focusing optical pickup device of the present invention as mentioned above, because make integratedly and be fixed in manufacture process on the accurate separately position such as optical elements such as beam splitter, diffraction grating and optical receivers, it is very simple that the manufacturing of this optic probe device and control become.
In addition, shorten light path by adopting such as the such optical element of Fresnel lens, optic probe device can very compact and miniaturization.
According to aforesaid dual focusing optical pickup device of the present invention, when laser beam is passed through the selective light transmissive piece, divide the laser beam of transmission on CD, to form less hot spot by inner circular part in the laser beam that the bigger hot spot of formation on the CD passes through the circumferential section transmission.Therefore, formed the twin-beam focus of different sizes by adopting an optic probe device, thus can be by the dish of two kinds of different densities of an optic probe device playback.
Therefore, for digital disc record and digital video disk, adopt optic probe device of the present invention all can reset with different registering capacities.
Although the present invention is shown specifically and illustrates with the reference accompanying drawing, those skilled in the art should be understood that under the premise without departing from the spirit and scope of the present invention and can carry out distortion on various forms and the details to the present invention.

Claims (7)

1. a dual focusing optical pickup device is characterized in that, comprising:
Lasing light emitter is used to produce laser beam with predetermined polarisation direction and the information of playback CD;
One-piece type optics, make laser beam towards the CD transmission and focus on the laser beam of returning by CD with predetermined polarisation direction, one-piece type optics has polarization beam splitting spare, the transmission quarter-wave plate, the reflection quarter-wave plate, light receiving piece, wherein, polarization beam splitting spare forms on the diagonal plane of one-piece type optics, be used for making laser beam also reflect the laser beam of returning from CD according to the polarization direction subsequently towards the CD transmission with predetermined polarisation direction according to the polarization direction, the transmission quarter-wave plate forms at the first surface in the face of CD of this one-piece type optics, be used for after light beam is by the beam splitting part, changing the polarization direction that turns back to the light beam of beam splitting part by dish, the reflection quarter-wave plate forms on the second surface of this one-piece type optics reception by beam splitting part beam reflected, be used to reflect by beam splitting part beam reflected and change the polarization direction of folded light beam, light receiving piece forms on the 3rd surface relative with the reflection quarter-wave plate, is used for detecting by reflection quarter-wave plate beam reflected;
The selective light transmissive piece, be arranged between one-piece type optics and the CD, be used for the light beam of transmission by propagating towards CD after the beam splitter transmission, the selective light transmissive piece has inner circular part and divides and circumferential section, the inner circular part branch is used for the first transmissivity transmission laser bundle, and circumferential section is used for the second transmissivity transmission laser bundle; And
Object lens are arranged between one-piece type optics and the CD, are used to make laser beam to focus on CD by one-piece type optics.
2. dual focusing optical pickup device as claimed in claim 1 is characterized in that, the selective light transmissive piece is formed on the first surface of one-piece type optics, and the transmission quarter-wave plate forms on the selective light transmissive piece.
3. dual focusing optical pickup device as claimed in claim 1, wherein the reflection horizon of prism has formed the Fresnel lens, is used to shorten light path.
4. dual focusing optical pickup device as claimed in claim 1 is characterized in that, diffraction grating is arranged on the reflection quarter-wave plate, and diffracted laser beam is used for tracking servo and focus servo.
5. dual focusing optical pickup device as claimed in claim 1 is characterized in that, holographic apparatus is arranged on the reflection quarter-wave plate, and diffracted beam is used for tracking servo and focus servo.
6. dual focusing optical pickup device as claimed in claim 1 is characterized in that, it is 1 total transmissivity spare that inner circular part is divided into transmissivity, and circumferential section is that transmissivity is 1/2 half transmitting spare.
7. optic probe device as claimed in claim 1 is characterized in that, divides the outermost angle of incident beam of transmission that the difference in size that focuses on the hot spot on the dish can be regulated by suitably adjusting through selective light transmissive piece inner circular part.
CN98125330A 1997-12-16 1998-12-14 Dual focusing optical pickup device Pending CN1220454A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR69007/97 1997-12-16
KR1019970069007A KR19990049985A (en) 1997-12-16 1997-12-16 Optical element integrated dual focus optical pickup device

Publications (1)

Publication Number Publication Date
CN1220454A true CN1220454A (en) 1999-06-23

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Application Number Title Priority Date Filing Date
CN98125330A Pending CN1220454A (en) 1997-12-16 1998-12-14 Dual focusing optical pickup device

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CN (1) CN1220454A (en)

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KR19990049985A (en) 1999-07-05

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