JP2009170021A - Optical pickup device and optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device having an optical system supporting three wavelengths, which is compact and can be mounted to a slim drive. <P>SOLUTION: A light path from a collimating lens 217 is separated at a first beam splitter 213 into a light path to a two-wavelength semiconductor laser light source 202 and a light path to a blue-violet semiconductor laser light source 201 and a PDIC 222, and the light paths of the blue-violet semiconductor laser light source 201 and the PDIC 222 are separated at BS2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup apparatus and an optical disc apparatus, and more particularly to an optical pickup apparatus and an optical information recording / reproducing apparatus that perform recording at three wavelengths.

  In recent years, development of a high-density optical information recording medium using a blue-violet laser with a short wavelength and an optical disk apparatus for recording / reproducing the same has been actively conducted. These apparatuses are required to be able to cope with media having different wavelengths such as CD and DVD.

Therefore, laser light sources D1 to D3 that emit laser beams L1 to L3 having a wavelength of 405 nm, 660 nm, and 780 nm, and a light receiving element that receives the laser beams L1 to L3 reflected by the optical disk DK and detects optical information. And a polarization beam splitter CS that branches the optical path from each of the laser light sources D1 to D3 to the optical disk DK and the optical path from the optical disk DK to the light receiving element PD, and between the polarization beam splitter CS and the light receiving element PD. In addition, a pickup including an optical filter CF that adjusts the amount of transmitted light in a wavelength band of 405 nm, a wavelength of 660 nm, and a wavelength of 780 nm is considered (Patent Document 1).
Japanese Patent Laying-Open No. 2005-141884

  In the above-mentioned document, since there is little common part of the optical path from the collimating lens to the light source D1 and the optical path from the collimating lens to the light receiving element, which is the longest optical path, the projection area occupied by the optical system becomes large, and the slim drive with a small space is achieved. There is a problem that it is difficult to mount.

  An object of the present invention is to provide an optical pickup device and an optical disc device having a three-wavelength compatible optical system that can be compactly mounted on a slim drive and can be constructed from inexpensive and few optical components.

  An optical pickup device according to an example of the present invention includes a first laser light source having a wavelength of 405 nm, a second laser light source having a wavelength of 660 nm, a third laser light source having a wavelength of 780 nm, and the first laser light source. , An objective lens that forms an image of the laser beam from the second laser light source and the third laser light source on the optical disc, and the reflected laser beam reflected by the optical disc is received to detect optical information. An optical pickup device having a light receiving element that performs the second laser beam and the third laser that reflect the first laser beam emitted from the first laser light source and emit the second laser light source By transmitting a third laser beam emitted from a light source, the first laser beam, the second laser beam, and the third laser are transmitted. And reflecting or transmitting the first laser beam emitted from the first laser light source, thereby changing the optical path of the first laser beam to the first optical element. And a second optical element superimposed on an optical path of the reflected laser beam directed from the element toward the light receiving element.

  An optical disc device according to an example of the present invention includes the optical pickup device.

  According to the present invention, it is possible to provide an optical pickup device having a three-wavelength compatible optical system that is compact and can be mounted on a slim drive, and that can be constructed from inexpensive and few optical components, and an optical disk device having the optical pickup device. it can.

  Embodiments of the present invention will be described below with reference to the drawings.

  An optical pickup device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a configuration of an optical disc apparatus according to an embodiment of the present invention. This optical disk apparatus can drive an optical disk such as a CD using an infrared laser beam, a DVD using a red laser beam, and an optical disk using a blue-violet laser (for example, an HD DVD or a bull-ray disc).

  As shown in FIG. 1, the optical disc apparatus 12 includes an eject button 14. When the eject button 14 is pressed, the drawer unit 16 stored in the main body is ejected.

  As shown in FIG. 2, the drawer unit 16 includes a drive circuit board unit of a drive and a mechanical unit 18. Further, the optical pickup unit (PUH) 28 of the mechanical unit 18 is driven so as to take a movement path in the α direction, which is a radial direction around the disk rotation motor (spindle motor) 22.

  As shown in FIG. 3, the mechanical unit 18 holds a spindle motor 22, a pickup unit 28, a mechanism for driving the spindle motor 22, the pickup unit 28, and the pickup unit 28, and further covers these mechanical units. The cover member 20 is provided. The pickup unit 28 is equipped with an objective lens 24 for emitting a reading laser. The mechanical unit 18 is connected to a predetermined circuit board of the optical disk device 12 by a flexible cable (FPC) 30.

  Next, a perspective view in which the cover member 20 is removed from the mechanical unit 18 is shown in FIG. The mechanical unit 18 is further provided with a main shaft (guide) 23 to which a rack gear for transmitting a driving force is attached as a pickup driving mechanism by applying a driving force from the pickup feeding motor to the pickup unit 28 via a lead screw and a rack gear meshed with the lead screw. And a sub shaft (guide) 25 that is on the opposite side of the main shaft 23 and supports the pickup portion 28 without being involved in transmission of driving force.

  The configuration of the optical pickup unit 28 is shown in the plan view of FIG.

  This optical pickup unit 28 can record / reproduce optical information to / from any of a high-density medium compatible with a blue-violet laser, an optical information recording medium compatible with a red laser, and an optical information recording medium compatible with an infrared laser. This is a possible three-wavelength optical pickup device.

  As shown in FIG. 5, the optical pickup unit includes a blue-violet semiconductor laser light source (first laser light source) 201 that emits a blue-violet laser beam having a wavelength of 405 nm, a red laser beam having a wavelength of 660 nm, and a red laser having a wavelength of 780 nm. A two-wavelength semiconductor laser light source (second laser light source, third laser light source) 202 that emits an outer laser beam, a diffraction grating 211, a magnification conversion lens 212, a first beam splitter 213, a diffraction grating 214, a second A beam splitter 215, a collimating lens 217, a quarter wavelength plate 218, a first mirror 219, an objective lens 24, a sensor lens 221, a signal detecting PDIC (Photo Diode-IC) 222, a monitor PD (Photo Diode) 223, and the like. Have.

  The first beam splitter 213 makes the optical path of the blue-violet laser beam emitted from the blue-violet semiconductor laser light source 201 and the optical path of the red laser beam and infrared laser beam emitted from the two-wavelength semiconductor laser light source 202 common. Is provided. The first beam splitter 213 is provided to reflect any of the laser beams incident on and reflected from the optical disc and to guide it to the signal detection PDIC.

  The first beam splitter 213 is preferably a plane parallel plate, and is covered with a transparent plane parallel plate (not shown) as a substrate and a multilayer optical thin film (or a protective film) applied on one surface thereof. A polarizing separation film (not shown) composed of a multilayer optical thin film) and an antireflection film (not shown) composed of a multilayer optical thin film (or a multilayer optical thin film covered with a protective film) applied on the other surface. And fulfills the function of optical path branching.

  The spectral characteristics of the first beam splitter 213 are shown in FIG. As shown in FIG. 6, most of the S-polarized light of the laser beam having a wavelength of 660 nm band and a wavelength of 780 nm band is transmitted, and a part thereof is reflected. Also, most of the s-polarized light of the 405 nm band laser beam is reflected.

  The first beam splitter 213 preferably has a reflectance of S-polarized light in the 405 nm band higher than 70% and a transmittance of S-polarized light in the 660 nm band and 780 nm band higher than 70%. Considering the power of semiconductor lasers currently used and losses in other optical elements, numerical values necessary for irradiating a laser beam with the power required to read information from or write information to the optical disk It is. More preferably, the first beam splitter 213 preferably has a reflectance of S-polarized light in the 405 nm band higher than 80% and a transmittance of S-polarized light in the 660 nm band and 780 nm band higher than 80%.

  In the case of this embodiment, the reflectance of the 405 nm band S-polarized light of the first beam splitter 213 is 90%, and the transmittance of the 660 nm band and 780 nm band of S-polarized light is 78%.

  The second beam splitter 215 causes the laser beam reflected by the optical disk reflected by the first beam splitter 213 to be incident on the signal detection PDIC 222, and the optical path of the blue-violet laser beam emitted from the blue-violet semiconductor laser light source 201. Is provided in order to cause the blue-violet laser beam to enter the first beam splitter in a direction substantially parallel to the moving direction of the optical pickup head.

  For example, the second beam splitter 215 has a configuration in which two glass prisms are bonded together via a dichroic film (not shown) made of a multilayer optical thin film. FIG. 7 shows the spectral characteristics of the second beam splitter. As shown in FIG. 7, most of the S-polarized light of the laser beam of the wavelength 660 nm band and the wavelength of 780 nm band is transmitted, most of the S-polarized light of the laser beam of the wavelength 405 nm band is reflected, and the P-polarized light of the laser beam of the wavelength 405 nm band It has a selectivity that allows most of it to permeate.

  The second beam splitter 215 preferably has a transmittance of P-polarized light in the 405 nm band higher than 70% and a transmittance of S-polarized light in the 660 nm band and 780 nm band higher than 70%. Considering the power of semiconductor lasers currently used and losses in other optical elements, numerical values necessary for irradiating a laser beam with the power required to read information from or write information to the optical disk It is. More preferably, the second beam splitter 215 preferably has a transmittance of P-polarized light in the 405 nm band higher than 80% and a transmittance of S-polarized light in the 660 nm band and 780 nm band higher than 80%.

In the case of this embodiment, it is preferable that the transmittance of P-polarized light in the 405 nm band of the second beam splitter 215 is higher than 70%, and the transmittance of S-polarized light in the 660 nm band and 780 nm band is higher than 70%. The signal detection PDIC 222 includes, for example, multi-divided PIN photodiodes, and outputs a current output proportional to the intensity of the incident light beam or an IV converted voltage from each element. For example, an information signal, a focus error signal, and a track error signal are generated from the output through a detection circuit (not shown).

  The light quantity monitoring PD 223 is a light receiving element for monitoring that detects the light quantity corresponding to the wavelength of the laser output of each laser light source with the laser beam transmitted (reflected) through the first beam splitter 213. The light intensity monitoring PD 223 is preferably tilted with respect to the chief ray of the laser beam in order to prevent ghosting.

  In this embodiment, focus error detection can employ a so-called astigmatism method, and track error detection can employ a DPD method or a DPP method (differential push-pull method). Since astigmatism is added when the laser beam passes through the cylindrical lens, a focus error signal can be obtained with a simple configuration.

  The laser beam emitted from the blue-violet semiconductor laser light source 201 will be described separately for the forward path and the return path. Here, the forward path refers to the optical path from the laser beam emitted from the blue-violet semiconductor laser light source 201 to the light recording spot on the information recording surface of the optical disk to form a light spot. The return path refers to the information recording surface of the medium. An optical path until the reflected return light is collected on the light detection surface of the light receiving element.

  First, the outward path will be described. The laser beam emitted from the blue-violet semiconductor laser light source 201 is a linearly polarized (S-polarized) divergent light. The laser beam emitted from the blue-violet semiconductor laser light source 201 is incident on the diffraction grating. The laser beam incident on the diffraction grating includes a main beam (0th order light) for recording / reproducing data on the optical disc and two sub beams (± 1st order light) for detecting tracking errors by the DPP method or the 3-beam method. Then, it is spectrally separated.

  The blue-violet laser beam emitted from the diffraction grating enters the second beam splitter 215. The blue-violet laser beam is mostly reflected by the second beam splitter 215, bent by an optical path of 90 degrees, and the optical path of the blue-violet laser beam emitted from the second beam splitter 215 is parallel to the moving direction of the optical pickup become. Then, most of the blue-violet laser beam is reflected by the first beam splitter 213 and enters the collimating lens 217. The collimating lens 217 converts the blue-violet laser beam into a substantially parallel beam. The laser beam converted into a substantially parallel beam by the collimator lens 217 enters the quarter wavelength plate 218. The quarter wave plate 218 converts the incident blue-violet laser beam into circularly polarized light. The blue-violet laser beam emitted from the quarter-wave plate 218 is incident on the first mirror 219 and the optical path of the blue-violet laser beam is bent so that the optical path of the blue-violet laser beam is orthogonal to the optical disc. The blue-violet laser beam whose optical path is bent enters the objective lens 24 and forms an image as a light spot on the information recording surface of the optical disk. The objective lens 24 is of a wavelength compatible type, and is not limited to a single lens system but may be a twin lens system.

  Next, the return path will be described. The reflected return light from the optical disk passes through the objective lens 24, the first mirror 219, the quarter wavelength plate 218, the collimator lens 217, and the first beam splitter 213 in the same way as the forward path. When transmitting through the quarter-wave plate 218, the blue-violet laser beam that was S-polarized light is converted to P-polarized light. The blue-violet laser beam mostly reflected by the first beam splitter 213 enters the second beam splitter 215. Most of the P-polarized blue-violet laser beam passes through the second beam splitter 215. The blue-violet laser beam transmitted through the second beam splitter 215 passes through the astigmatism sensor lens 221 and enters the signal detection PDIC 222. The optical information included in the incident light is detected by the signal detection PDIC 222. It is desirable to set the optical magnification of the return path as high as possible in order to increase the focus detection sensitivity, and in particular to reduce interlayer interference in a multilayer disk.

  Next, the red laser beam or infrared laser beam emitted from the two-wavelength semiconductor laser light source 202 will be described separately for the forward path and the backward path. Here, the forward path refers to an optical path from when a red laser beam or an infrared laser beam is emitted from the two-wavelength semiconductor laser light source 202 to be focused on the information recording surface of the optical disk to form a light spot. The optical path until the reflected return light from the information recording surface is collected on the light detection surface of the light receiving element.

  First, the outward path will be described. The red laser beam or infrared laser beam emitted from the two-wavelength semiconductor laser light source 202 is a linearly polarized (S-polarized) divergent light. The red laser beam or infrared laser beam emitted from the two-wavelength semiconductor laser light source 202 is incident on the diffraction grating 211. A red laser beam or an infrared laser beam incident on the diffraction grating 211 is divided into two main beams (zero-order light) for recording / reproducing data on an optical disc and two for detecting a tracking error by the DPP method or the three-beam method. It is split into sub-beams (± primary light).

  Laser beams having a plurality of wavelengths are not simultaneously emitted from the two semiconductor laser light sources. For example, it is determined which laser light source to use in accordance with the difference in the thickness of the optical disk or information recorded on the optical disk. Based on the determination, one of the two laser light sources is turned on, a laser beam having a predetermined wavelength is emitted, and optical information is recorded on or reproduced from the information recording surface of the optical disc.

  The red laser beam or infrared laser beam emitted from the diffraction grating 211 enters the magnification conversion lens. The magnification conversion lens 212 is provided to increase the light efficiency. Since the recording density is low with respect to the spot size in the order of the infrared laser beam, red laser beam, and blue-violet laser beam, especially the infrared laser beam has a reduced rim intensity of the objective lens incident light and a larger spot size. Higher light efficiency and higher recording speed are more valuable. Therefore, by passing the magnification conversion lens 212, the light efficiency of the infrared laser beam is increased. With this magnification conversion lens, the optical magnification of the infrared laser beam and the red laser beam is lower than the optical magnification of the blue-violet laser beam. As a result, the distance from the collimating lens to the second light source and the third light source is reduced. Longer than the distance from the first light source.

  Most of the red laser beam or infrared laser beam emitted from the magnification conversion lens 212 is transmitted through the first beam splitter 213 and is common to the optical path of the blue-violet laser beam reflected by the first beam splitter 213.

  Then, the red laser beam or the infrared laser beam is incident on the collimating lens 217, and the collimating lens 217 converts the red laser beam or the infrared laser beam into a substantially parallel beam. The red laser beam or infrared laser beam converted into a substantially parallel beam by the collimator lens 217 is incident on the quarter wavelength plate 218. The quarter wavelength plate 218 converts the incident red laser beam or infrared laser beam into circularly polarized light. The red laser beam or infrared laser beam emitted from the quarter wavelength plate 218 is incident on the first mirror 219 so that the optical path of the red laser beam or infrared laser beam is orthogonal to the optical disc. become. The red laser beam or infrared laser beam whose optical path is bent is incident on the objective lens 24 and forms an image as a light spot on the information recording surface of the optical disk.

  Next, the return path will be described. The reflected light from the optical disk reflects the objective lens 24, the first mirror 219, the quarter wavelength plate 218, and the first beam splitter 213 in the opposite direction to the outward path. When the light passes through the quarter-wave plate 218, the red laser beam or infrared laser beam that has been S-polarized light is converted to P-polarized light. About 20% of the P-polarized light of the red laser beam or the infrared laser beam is reflected by the first beam splitter 213, and enters the second beam splitter 215. Most of the P-polarized red laser beam or infrared laser beam passes through the second beam splitter 215, passes through the astigmatism sensor lens 221, and enters the signal detection PDIC 222. The optical information included in the incident light is detected by the signal detection PDIC 222.

  In this way, the optical pickup unit of this apparatus uses a blue-violet semiconductor laser light source 201 that emits a blue-violet laser beam with a wavelength of 405 nm band and a signal detection PDIC 222 that receives the reflected laser beam of the optical disc and detects optical information. The optical path from the collimating lens 217, which is the longest optical path, to the blue-violet semiconductor laser light source 201 and the collimating lens are arranged close to each other via one second beam splitter 215 on the side far from the optical disc center in the moving direction of the pickup. The common part of the optical path from 217 to the signal detection PDIC 222 is increased. Further, a two-wavelength semiconductor laser light source 202 having a wavelength of 660 nm and a wavelength of 780 nm and a magnification conversion lens 212 for increasing the light efficiency of the laser beam having a wavelength of 780 nm are disposed in a direction substantially orthogonal to the moving direction of the optical pickup. The optical path from the collimating lens 217 to these optical elements includes a part of the optical path of the blue-violet laser beam from the blue-violet semiconductor laser light source 201.

  In this apparatus, as shown in FIG. 5, since the distance from the objective lens to the main shaft 23 or the sub shaft 25 is short, the two-wavelength semiconductor laser light source 202 that emits a two-wavelength semiconductor laser having a low optical magnification is used as the main shaft 23 ( Alternatively, it is arranged on the lucky shaft 25) side. Further, since the distance from the objective lens to the outer peripheral direction of the optical disk is also limited, after the blue-violet semiconductor laser light source 201 is emitted in a direction substantially orthogonal to the longitudinal direction of the main shaft 23 (or the full axis 25), the second Bend in the radial direction of the disk with a beam splitter. The positions of the blue-violet semiconductor laser light source 201 and the signal detection PDIC are interchangeable.

  As a result of the layout described above, the projection area of the optical pickup unit can be reduced, which is suitable for an optical disk device mounted on a notebook computer.

  The red laser beam and infrared laser beam emitted from the two-wavelength semiconductor laser light source 202 can be made to be P-polarized light by rotating the polarization plane using a λ / 2 plate. In this case, as shown in FIG. 8, the spectral characteristics of the first beam splitter 213 are set such that the transmittance of P-polarized light in the 660 nm band and the 780 nm band is as high as about 80%, and the transmittance of S-polarized light is 50%. The degree (reflectance about 50%). The red laser beam and the infrared laser beam reflected by the optical disk are incident on the first beam splitter as S-polarized light, and about 50% of the S-polarized light is reflected and incident on the second beam splitter 215. As shown in FIG. 9, the spectral characteristics of the second beam splitter 215 are such that the transmittance of S-polarized light and P-polarized light is about 50% in the 660 nm band and the 780 nm band.

  Further, although the two-wavelength semiconductor laser light source 202 is used as the light source of the red laser beam and the infrared laser beam, the light sources 231 and 241 may be used for each laser beam as shown in FIG.

  As shown in FIG. 10, the infrared laser beam emitted from the infrared semiconductor laser light source 231 passes through the diffraction grating 232 and the magnification conversion lens 233 and enters the prism 251. The infrared laser beam passes through the prism 251 and enters the first beam splitter 213. Further, the red laser beam emitted from the red semiconductor laser light source 241 passes through the diffraction grating 242 and the magnification conversion lens 243 and enters the prism 251. The red laser beam is reflected by the prism 251 and enters the first beam splitter 213. The optical path of the infrared laser beam passing through the prism 251 and the optical path of the red laser beam reflected by the prism are common. Since the optical paths of the red laser beam and the infrared laser beam incident on the first beam splitter 213 are the same as described above, the description is omitted. In this case, the focal length of the magnification conversion lens is set so that the optical magnification of the infrared laser beam is lower than the optical magnification of the red laser beam.

  In this way, the optical pickup unit of this apparatus uses a blue-violet semiconductor laser light source 201 that emits a blue-violet laser beam with a wavelength of 405 nm band and a signal detection PDIC 222 that receives the reflected laser beam of the optical disc and detects optical information. The optical path from the collimating lens 217, which is the longest optical path, to the blue-violet semiconductor laser light source 201 and the collimating lens are arranged close to each other via one second beam splitter 215 on the side far from the optical disc center in the moving direction of the pickup. The common part of the optical path from 217 to the signal detection PDIC 222 is increased. Further, the optical efficiency of the laser beam from the red semiconductor laser light source 241 with the wavelength of 660 nm, the infrared semiconductor laser light source 231 with the wavelength of 780 nm, and the infrared semiconductor laser light source 231 is set in a direction substantially orthogonal to the moving direction of the optical pickup. A magnification conversion lens 212 for increasing the height is arranged so that the optical path from the collimating lens 217 to these optical elements includes a part of the optical path of the blue-violet laser beam from the blue-violet semiconductor laser light source 201.

  In addition, each laser light source has an elliptical distribution of the beam cross section, and is arranged so that its major axis faces the track direction of the optical disc. The angle between the major axis direction and the track direction is 30. It is good also as 45 degree | times or 45 degree | times. In this case, a λ / 2 plate is disposed in front of each laser light source, and the optical axis of the λ / 2 plate is set so that the polarization direction is a predetermined direction with respect to the beam splitter.

  When the blue-violet laser beam emitted from the blue-violet semiconductor beam light source 201 is used for a read-only drive without recording on the recording disk, the spectral characteristics of the second beam splitter 215 are as shown in FIG. It may be.

  When recording on a recording disk, it is necessary to irradiate the disk with a high-power laser beam. However, in the case of a read-only drive, it is not necessary to irradiate the disk with a high-power blue-violet laser beam. Therefore, as shown in FIG. 11, a beam splitter having a low S-polarized light reflectance can be used.

  Note that the second beam splitter 215 preferably has a transmittance of P-polarized light in the 405 nm band, the 660 nm band, and the 780 nm band higher than 70%. Considering the power of semiconductor lasers currently used and losses in other optical elements, numerical values necessary for irradiating a laser beam with the power required to read information from or write information to the optical disk It is. More preferably, the second beam splitter 215 has a transmittance of P-polarized light in the 405 nm band, the 660 nm band, and the 780 nm band.

  In this case, as shown in FIG. 12, a plate-type beam splitter 215A can be used instead of a configuration in which the second beam splitter is bonded to two glass prisms. By using the plate-type beam splitter 215A, the cost is lower than a beam splitter having a configuration in which two glass prisms are bonded together.

  As shown in FIG. 13, not the wavelength-compatible type single lens system but the two-lens system of the blue-purple objective lens 24A and the CD / DVD compatible (red and infrared compatible) objective lens 24B, The effects described in this embodiment can be obtained. In FIG. 13, the beam splitter 301 has a characteristic that a red laser beam and an infrared laser beam are transmitted and a blue-violet laser beam is reflected. The third mirror 301 has a characteristic of reflecting the red laser beam and the infrared laser beam.

  Further, in the same optical path as in FIG. 5, the two objective lenses 24 </ b> A and 24 </ b> B cannot be disposed between the main shaft 23 and the sub shaft 25. Therefore, in the case of the two-lens method, the second mirror 216 reflects the laser beam whose optical path is overlapped by the first beam splitter 213 and the laser beam from the optical disc. A collimating lens 217 is disposed on the optical path between the first beam splitter 213 and the second mirror 216.

  Even in the case of the two-lens system, as shown in FIG. 14, a plate-type beam splitter 215B can be used instead of a configuration in which the second beam splitter is bonded to two glass prisms. By using the plate-type beam splitter 215A, the cost is lower than a beam splitter having a configuration in which two glass prisms are bonded together.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a perspective view showing a configuration of an optical disc apparatus according to an embodiment of the present invention. The perspective view which shows the drawer part of the optical disk apparatus shown in FIG. The perspective view which shows the mechanical unit of the drawer part shown in FIG. The perspective view which removed the cover member from the mechanical unit shown in FIG. The figure which shows the structure of the optical pick-up part concerning one Embodiment of this invention. FIG. 6 is a diagram illustrating spectral characteristics of a first beam splitter of the optical pickup unit illustrated in FIG. 5. FIG. 6 is a diagram illustrating spectral characteristics of a second beam splitter of the optical pickup unit illustrated in FIG. 5. The figure which shows the spectral characteristic of the 1st beam splitter of the modification of an optical pick-up part. The figure which shows the spectral characteristics of the 2nd beam splitter of the modification of an optical pick-up part. The figure which shows the modification of a structure of an optical pick-up part. FIG. 6 is a diagram illustrating spectral characteristics of a second beam splitter of the optical pickup unit illustrated in FIG. 5. The figure which shows the modification of a structure of an optical pick-up part. The figure which shows the modification of a structure of an optical pick-up part. The figure which shows the modification of a structure of an optical pick-up part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 12 ... Optical disk apparatus, 14 ... Eject button, 16 ... Drawer part, 18 ... Mechanical unit, 20 ... Cover member, 22 ... Spindle motor, 23 ... Main axis, 24 ... Objective lens, 25 ... Secondary axis, 28 ... Optical pick-up , 30 ... flexible cable, 201 ... blue-violet semiconductor laser light source, 202 ... dual wavelength semiconductor laser light source, 211 ... diffraction grating, 212 ... magnification conversion lens, 213 ... first beam splitter, 214 ... diffraction grating, 215 ... second 217 ... collimating lens, 218 ... 1/4 wavelength plate, 219 ... first mirror, 221 ... sensor lens, 222 ... signal detection PDIC, 223 ... light quantity monitoring PD.

Claims (10)

A first laser light source having a wavelength of 405 nm; a second laser light source having a wavelength of 660 nm; a third laser light source having a wavelength of 780 nm; the first laser light source; the second laser light source; An optical pickup device having an objective lens that forms an image of any one of the laser beams from the laser light source 3 on the optical disc, and a light receiving element that receives the reflected laser beam reflected by the optical disc and detects optical information. ,
The first laser beam emitted from the first laser light source is reflected, and the second laser beam emitted from the second laser light source and the third laser beam emitted from the third laser light source are transmitted. A first optical element that overlaps the optical paths of the first laser beam, the second laser beam, and the third laser beam,
By reflecting or transmitting the first laser beam emitted from the first laser light source, the optical path of the first laser beam is directed from the first optical element to the light receiving element. And a second optical element stacked on the optical pickup device.   The reflectance of S-polarized light in the 405 nm band of the first optical element is higher than 70%, and the transmittance of S-polarized light in the 660 nm band and 780 nm band of the first optical element is higher than 70%. The optical pickup device according to claim 1.   The transmittance of P-polarized light in the 405 nm band of the second optical element is higher than 70%, and the transmittance of S-polarized light in the 660 nm band and 780 nm band of the second optical element is higher than 70%. The optical pickup device according to claim 2.   2. The optical pickup device according to claim 1, wherein the first optical element has a reflectance of S-polarized light in a 405 nm band higher than 70% and a transmittance of P-polarized light in a 660 nm band and a 780 nm band higher than 70%. .   5. The optical pickup device according to claim 4, wherein the transmittance of P-polarized light in the 405 nm band, the 660 nm band, and the 780 nm band of the second optical element is higher than 70%. An optical disc device having an optical pickup device that translates along a guide,
The optical pickup device is:
A first laser light source having a wavelength of 405 nm;
A second laser light source having a wavelength of 660 nm, a third laser light source having a wavelength of 780 nm,
An objective lens that forms an image of any laser beam from the first laser light source, the second laser light source, and the third laser light source on an optical disc;
A light receiving element that receives a reflected laser beam reflected by the optical disc and detects optical information;
The first laser beam emitted from the first laser light source is reflected, and the second laser beam emitted from the second laser light source and the third laser beam emitted from the third laser light source are transmitted. A first optical element that overlaps the optical paths of the first laser beam, the second laser beam, and the third laser beam,
Reflecting or transmitting the first laser beam emitted from the first laser light source, the optical path of the first laser beam is directed from the first optical element to the light receiving element. And a second optical element superimposed on the optical disk apparatus.   The first optical element has a 405 nm band S-polarized light reflectance higher than 70%, and the first optical element has a 660 nm band and 780 nm band S-polarized light transmittance higher than 70%. The optical disc apparatus according to claim 6.   The transmittance of P-polarized light in the 405 nm band of the second optical element is higher than 70%, and the transmittance of S-polarized light in the 660 nm band and 780 nm band of the second optical element is higher than 70%. The optical disk device according to claim 7.   7. The optical disk device according to claim 6, wherein the first optical element has a reflectance of S-polarized light in the 405 nm band higher than 70% and a transmittance of P-polarized light in the 660 nm band and 780 nm band higher than 70%. .   10. The optical disk device according to claim 9, wherein the transmittance of P-polarized light in the 405 nm band, 660 nm band, and 780 nm band of the second optical element is higher than 70%.

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