JP2006134474A - Optical pickup and optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an optical pickup and optical disk drive of a thin structure corresponding to two or more wavelengths. <P>SOLUTION: The optical pickup 10 is provided with a 1st laser light source 21 for emitting 1st laser light, a 1st objective lens 62 which corresponds to a wavelength of the 1st laser light and emits the 1st laser light to an optical disk, a 2nd laser light source 41 for emitting 2nd laser light of a wavelength different from that of the 1st laser light, a 2nd objective lens 63 which corresponds to a wavelength of the 2nd laser light and emits the 2nd laser light to the optical disk, a 1st optical path 20 for guiding the 1st laser light to the 1st objective lens 62 from the 1st laser light source 21, a 2nd optical path 40 for guiding the 2nd laser light to the 2nd objective lens 63 from the 2nd laser light source 41, an optical path synthesis means 61 for synthesizing a part of the 1st and 2nd optical paths, and an optical path separating means 66 for separating synthesized optical path synthesized by the optical path synthesis means 61 at the preceding stage of the 1st and 2nd objective lenses 62 and 63. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical pickup and an optical disc drive, and is suitable for application to an optical disc drive adapted to use a plurality of types of optical discs.

  2. Description of the Related Art Conventionally, there are optical disk drives that can perform recording and reproduction on two types of optical disks, CD (Compact Disk) and DVD (Digital Versatile Disk).

The wavelength of the laser beam used for the CD is 780 [nm], whereas the wavelength of the laser beam used for the DVD is 650 [nm], and both wavelengths are relatively close to each other. For this reason, in an optical disk drive for both CD / DVD, the entire apparatus can be miniaturized by commonly using the optical path composed of an objective lens, a collimator lens, etc. for the laser beam for CD and the laser beam for DVD ( For example, see Patent Document 1).
JP 2002-298869 A

  In recent years, Blu-ray Disc (registered trademark) using blue-violet laser light having a wavelength of 405 [nm] has been put into practical use. The Blu-ray disc uses a laser beam with a much shorter wavelength than a conventional optical disc, and therefore has a recording capacity several times that of a DVD having the same disc diameter. A three-wavelength optical disc drive that can use this Blu-ray disc together with a CD or DVD has been put into practical use.

  However, as described above, the wavelength of the laser beam for Blu-ray Disc has a wavelength of 405 [nm], which differs greatly from the wavelength of the laser beam for CD or DVD. It is difficult. For this reason, in an optical disk drive compatible with three wavelengths, it is realistic to provide two objective lenses for a Blu-ray disc and a CD / DVD on the optical pickup.

  Here, if the optical path for the Blu-ray disc and the optical path for the CD / DVD are completely separated, the apparatus design becomes easy, but there is a problem that the size of the optical pickup becomes large. For this reason, in a three-wavelength optical pickup, two objective lenses for Blu-ray Disc and CD / DVD are mounted on a single biaxial actuator, and laser light is supplied from the respective optical paths for Blu-ray Disc and CD / DVD. Can be introduced into the corresponding objective lens.

  Even in this case, two raising mirrors for introducing the laser beam into the objective lens are required for Blu-ray disc and CD / DVD. However, in practice, the biaxial actuator has a complicated structure including a lens support mechanism, a driving coil, and the like, and therefore, the laser beam introduction range for the biaxial actuator is limited. In particular, a thin optical disk drive (so-called slim drive) mounted on a notebook computer limits the thickness of the entire device, further limiting the range of laser light introduction, which makes it difficult to reduce the thickness of the optical pickup itself. There was a problem of being.

  The present invention has been made in consideration of the above points, and intends to propose an optical pickup and an optical disk drive having a thin structure corresponding to a plurality of wavelengths.

  In order to solve such a problem, in the present invention, a first laser light source that emits a first laser beam, and a first laser beam that emits the first laser beam to an optical disc corresponding to the wavelength of the first laser beam. One objective lens, a second laser light source that emits a second laser beam having a wavelength different from that of the first laser beam, and the second laser beam corresponding to the wavelength of the second laser beam to the optical disc A second objective lens that emits light, a first optical path that guides the first laser light from the first laser light source to the first objective lens, and a second laser light from the second laser light source to the second A second optical path that leads to the objective lens, an optical path synthesis unit that synthesizes a part of the first and second optical paths, and a synthesized optical path synthesized by the optical path synthesis unit are arranged in front of the first and second objective lenses. The optical pickup is provided with optical path separating means for separating.

  The first objective lens and the second objective lens are provided in the same biaxial actuator, and the optical path synthesizing unit is configured so that the first and second laser beams are arranged on the optical path before the first and second laser beams are introduced into the biaxial actuator. The first and second optical paths are synthesized.

  Two axes with a thin structure in which the introduction range of laser light is limited by sharing the first and second optical paths in front of the biaxial actuator and separating them in front of the first and second objective lenses An optical pickup having a thin structure corresponding to a plurality of wavelengths can be formed using an actuator.

  According to the present invention, since the first and second optical paths are made common in front of the biaxial actuator and further separated in the front stage of the first and second objective lenses, the introduction range of the laser light is limited. An optical pickup corresponding to a plurality of wavelengths can be configured by using the thin-structured two-axis actuator, and thus a thin-structure optical pickup and an optical disk drive corresponding to a plurality of wavelengths can be realized.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Overall Configuration of Optical Disc Drive FIG. 1 shows an optical disc drive 1 to which the present invention is applied as a whole, and a disc tray portion 3 is attached to a box-shaped housing 2 so as to be housed and ejected. The disc tray 3 has a chuck 4 for mounting the optical disc 100, a spindle motor (not shown) that drives the optical disc 100 to rotate via the chuck 4, and irradiates the recording surface of the optical disc 100 with laser light and reflects it. An optical pickup 10 that receives light and a sled mechanism (not shown) that reciprocally moves the entire optical pickup 10 in the radial direction of the optical disc 100 are provided.

  The optical disk drive 1 is of a three-wavelength compatible type, and performs recording and reproduction on three types of optical disks: CD, DVD, and Blu-ray disk. The optical disk drive 1 is a thin disk drive called a so-called slim drive, and can be mounted on a notebook personal computer or the like with a limited thickness of the casing.

(2) Configuration of Optical Pickup FIG. 2A shows a three-wavelength compatible optical pickup 10 that is configured by mounting various optical elements on a base 11. The optical system in the optical pickup 10 is called a CD / DVD optical system 20 for performing recording / reproduction with respect to a CD and a DVD, and a BD optical system optical system for performing recording / reproduction with respect to a Blu-ray disc disc (hereinafter abbreviated as BD). 40) It is composed of a common optical system 60 used in common for the three parties of CD, DVD and BD.

(2-1) Configuration of CD / DVD Optical System In the CD / DVD optical system 20, the laser light emitted from the CD / DVD laser diode 21 as the first laser light source is used as the first laser light. The emitted light for CD / DVD enters the collimator lens 26 through the coupling lens 22, the mirror 23, the grating 24, and the beam splitter 25 in this order. The collimator lens 26 converts the emitted light for CD / DVD into parallel light and enters the common optical system 60.

  The beam splitter 61 for optical path synthesis of the common optical system 60 reflects a part of the emitted light for CD / DVD at a right angle and enters the front photodiode 27 for laser power detection. As will be described in detail later, the common optical system 60 irradiates the recording surface of the optical disc 100 with the remainder of the emitted light for CD / DVD through the objective lens 62 for CD / DVD and the reflected light for CD / DVD. The incident light is received by the CD / DVD objective lens 62 and is incident on the CD / DVD optical system 20.

  Then, the CD / DVD optical system 20 enters the incident light for CD / DVD into the beam splitter 25 via the collimator lens 26. The beam splitter 25 reflects incident light for CD / DVD at a right angle, and enters a detection PDIC (Photo Detector IC) 30 through a cylindrical lens 28 and a hologram 29. The PDIC 30 photoelectrically converts the incident light for CD / DVD and outputs various signals such as a reproduction signal, a tracking error signal, and a focus error signal.

(2-2) Configuration of BD Optical System On the other hand, in the BD optical system 40, the laser light emitted from the BD laser diode 41 as the second laser light source is used as the emitted light for BD as the second laser light. Then, the polarization plane is rotated by the polarization means 42 composed of a wave plate, a grating, or a composite element thereof, and then enters the beam splitter 43.

  The beam splitter 43 transmits a part of the emitted light for BD and enters the front photodiode 45 for laser power detection via the collimator lens 44. The beam splitter 43 reflects the remainder of the emitted light for BD and enters the collimator lens 48 through the beam splitter 46 and the mirror 47 in order. The collimator lens 48 converts the emitted light for BD into parallel light and enters the common optical system 60.

  The beam splitter 61 for synthesizing the optical path of the common optical system 60 reflects the emitted light for BD at a right angle, irradiates the recording surface of the optical disc 100 via the BD objective lens 63, and uses the reflected light as incident light for BD. Light is received by the BD objective lens 63 and is incident on the BD optical system 40.

  The BD optical system 40 makes incident light for BD enter the beam splitter 46 through the collimator lens 48 and the mirror 47 in order. The beam splitter 46 transmits the BD emission light and enters the detection PDIC 51 via the hologram 49 and the coupling lens 50. The PDIC 51 photoelectrically converts incident light for BD and outputs various signals such as a reproduction signal, a tracking error signal, and a focus error signal.

(2-3) Configuration of Common Optical System Next, the configuration of the common optical system 60 that is a feature of the present invention will be described in detail. In this common optical system 60, a CD / DVD objective lens 62 and a BD objective lens 63 are mounted on the same biaxial actuator 68, and below the CD / DVD objective lens 62 and the BD objective lens 63. 1 includes a rising mirror unit 65 including a BD rising mirror 66 and a CD / DVD rising mirror 67.

  That is, as shown in FIG. 2B, a CD / DVD rising mirror 66 is provided below the CD / DVD objective lens 62, and a BD rising edge is provided below the BD objective lens 63. A mirror 67 is provided, and the optical path combining beam splitter 61, the BD rising mirror 67, and the CD / DVD rising mirror 66 are arranged in a straight line.

  As described above, in the common optical system 60, both the emitted light for CD / DVD and the emitted light for BD are incident on an optical path combining beam splitter 61 as optical path combining means. The common optical system 60 uses a CD / DVD outgoing light and a BD outgoing light transmitted through the optical path combining beam splitter 61, via a spherical aberration correcting liquid crystal element 64, as a BD rising mirror as an optical path separating means. 67 is incident.

  The BD stand-up mirror 67 is a wavelength selective beam splitter and reflects 90 ° of only blue-violet laser light having a wavelength of 405 [nm] for a Blu-ray disc. For this reason, when the incident outgoing light is the BD outgoing light, the BD rising mirror 67 reflects the BD outgoing light and rises upward, and passes through the optical disc 100 (in this case) via the BD objective lens 63. The BD incident light received through the BD objective lens 63 is reflected and incident on the BD optical system 40 through the liquid crystal element 64 and the optical path combining beam splitter 61.

  On the other hand, when the incident outgoing light is CD / DVD outgoing light, the BD rising mirror 67 transmits the CD / DVD outgoing light and enters the CD / DVD rising mirror 66. The CD / DVD raising mirror 66 reflects the emitted light for CD / DVD and rises upward, irradiates the optical disk 100 (in this case, CD or DVD) via the CD / DVD objective lens 62, and The incident light for CD / DVD received through the DVD objective lens 62 is reflected, and is incident on the CD / DVD optical system 20 through the BD rising mirror 67, the liquid crystal element 64, and the optical path combining beam splitter 61.

(3) Operation and Effect In the above configuration, in the optical pickup 10, the CD / DVD objective lens 62 and the BD objective lens 63 are mounted on the same biaxial actuator 68 and emitted from the CD / DVD optical system 20. Both the emitted light for CD / DVD and the emitted light for BD emitted from the BD optical system 40 are incident on the rising mirror unit 65 via the beam splitter 61 for optical path synthesis of the common optical system 60.

  Then, the CD / DVD emission light and the BD emission light are separated by the BD rising mirror 67 formed of a wavelength selective beam splitter and emitted through the corresponding objective lens 62 or 63.

  In this way, the biaxial actuator that holds the objective lenses 62 and 63 by synthesizing the optical paths of the CD / DVD outgoing light and the BD outgoing light when entering the rising mirror section 65 by the optical path synthesizing beam splitter 61. The optical paths of the CD / DVD emission light and the BD emission light with respect to 67 are made common. Accordingly, the three-wavelength compatible optical pickup 10 can be configured using the thin biaxial actuator 67 having a limited laser light introduction range.

  According to the above configuration, a part of the optical path for CD / DVD and BD is shared by the beam splitter 61 for optical path synthesis, and the optical path for CD / DVD and BD is separated by the rising mirror unit 65. The thin and three-wavelength compatible optical pickup 10 is configured by using the thin biaxial actuator 67 with a limited introduction range of the laser light by being incident on the corresponding objective lenses 62 and 63. Thus, the optical disc drive 1 having a thin structure corresponding to a plurality of wavelengths can be realized.

(4) Other Embodiments In the above-described embodiments, a part of the two optical paths for CD / DVD and BD are shared by the beam splitter 61 for optical path synthesis. Not limited to this, optical paths for CD, DVD, and BD may be provided separately, and a part of these three optical paths may be shared by the optical path combining beam splitter and introduced into the rising mirror unit 65. . Further, the optical disk to be used by the optical disk drive 1 is not limited to CD, DVD and BD, and can be applied to various optical disks.

  The present invention can be applied to various optical disk drives.

It is a rough-line perspective view which shows the whole structure of an optical disk drive. It is a basic diagram which shows the structure of the optical pick-up corresponding to a thin drive by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical disc drive, 2 ... Housing, 3 ... Disc tray, 4 ... Chuck, 10 ... Optical pick-up, 11 ... Base, 20 ... CD / DVD optical system, 21 ... For CD / DVD Laser diode, 22 ... coupling lens, 23, 47 ... mirror, 24 ... grating, 25, 43, 46 ... beam splitter, 26, 44, 48 ... collimator lens, 27, 45 ... front photodiode 28 ...... Cylindrical lens, 29 ... Hologram, 30 ... PDIC, 40 ... BD optical system, 41 ... BD laser diode, 42 ... Polarization means, 60 ... Common optical system, 61 ... Optical path synthesis Beam splitter, 62 ... CD / DVD objective lens, 63 ... BD objective lens, 64 ... Liquid crystal element, 65 ... Launching mirror Part, raising mirror for 66 ...... CD / DVD, raising mirror for 67 ...... BD, 68 ...... 2-axis actuator.

Claims (4)

A first laser light source that emits a first laser beam;
A first objective lens that corresponds to the wavelength of the first laser beam and emits the first laser beam to the optical disc;
A second laser light source that emits a second laser beam having a wavelength different from that of the first laser beam;
A second objective lens that corresponds to the wavelength of the second laser beam and emits the second laser beam to the optical disc;
A first optical path for guiding the first laser light from the first laser light source to the first objective lens;
A second optical path for guiding the second laser light from the second laser light source to the second objective lens;
Optical path combining means for combining a part of the first and second optical paths;
An optical pickup comprising: an optical path separating means for separating the combined optical path synthesized by the optical path synthesizing means at a stage preceding the first and second objective lenses. The first and second objective lenses are provided in the same biaxial actuator, and the optical path synthesizing means is on the optical path before the first and second laser beams are introduced into the biaxial actuator. The optical pickup according to claim 1, wherein the first and second optical paths are combined. The optical path separation means has wavelength selectivity, and is synthesized by the optical path synthesis means by separating the first and second laser lights according to the wavelengths of the first and second laser lights. The optical pickup according to claim 1, wherein the optical path is separated. A first laser light source that emits a first laser beam;
A first objective lens that corresponds to the wavelength of the first laser beam and emits the first laser beam to the optical disc;
A second laser light source that emits a second laser beam having a wavelength different from that of the first laser beam;
A second objective lens that corresponds to the wavelength of the second laser beam and emits the second laser beam to the optical disc;
A first optical path for guiding the first laser light from the first laser light source to the first objective lens;
A second optical path for guiding the second laser light from the second laser light source to the second objective lens;
Optical path combining means for combining a part of the first and second optical paths;
An optical disk drive comprising: an optical path separating means for separating the combined optical path synthesized by the optical path synthesizing means at a stage preceding the first and second objective lenses.

Images