JP2008257780A - Optical pickup device, optical recording/reproducing device and recording/playing method for optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device which is mounted with three laser diodes for emitting beams of three wavelengths and has a common objective lens, the optical pickup device being configured to supply a sufficient laser output to each recording medium. <P>SOLUTION: The optical pickup device 1 includes a first laser diode 31 for emitting a laser beam of a wavelength of 399 to 413 nm, a second laser diode 41 for emitting a laser beam of a wavelength of 630 to 660 nm, a third laser diode 42 for emitting a laser beam of a wavelength of 770 to 790 nm, an objective lens 14 disposed on an common optical path, and a control section 2 for controlling the operation of each laser diode. The ratio of a laser beam output after passage through the objective lens 14 to an emission output is the smallest in the third laser diode 42. Recording in a CD is carried out by a laser beam emitted from the first or second laser diode 31 or 41, and playing of the CD is carried out by a laser beam emitted from the third laser diode 42. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup device, an optical recording / reproducing device, and an optical recording medium recording / reproducing method, and more particularly to a configuration of an optical pickup device using laser beams having wavelengths of 399 to 413 nm, 630 to 660 nm, and 770 nm to 790 nm.

  Conventionally, an optical pickup device that performs recording / reproduction on a CD (Compact Disc) using a laser beam having a wavelength of around 780 nm, and an optical pickup device that performs recording / reproduction on a DVD (Digital Versatile Disc) using a laser beam near a wavelength of 650 nm It has been known. When a plurality of wavelengths of laser light are handled by a single optical pickup device, a configuration in which an optical path is shared without providing an optical system corresponding to each wavelength is common. By sharing the optical path, optical components such as an objective lens and a beam splitter can be shared. In this case, it is common to perform recording / reproduction of a CD using a laser beam having a wavelength of about 780 nm and recording / reproduction of a DVD using a laser beam having a wavelength of about 650 nm, but using a laser beam having a wavelength of about 650 nm. It is possible to record and reproduce both CD and DVD. Since the laser beam having a wavelength of about 650 nm can be recorded and reproduced with less energy, the latter method is advantageous in terms of power consumption. However, CD-R (CD-Recordable) has a reflectance peak in the vicinity of a wavelength of about 780 nm, and thus is not suitable for reproduction with a laser beam of a wavelength of about 650 nm. Therefore, CD-R is disclosed with a technique of recording with a laser beam having a wavelength of about 650 nm and reproducing with a laser beam having a wavelength of about 780 nm (Patent Documents 1 and 2). Also disclosed is a technique in which a laser beam having a wavelength of about 650 nm and a laser beam having a wavelength of about 780 nm are simultaneously irradiated during recording, and only a laser beam having a wavelength of about 780 nm is irradiated during reproduction (Patent Document 3).

When providing a common optical path, only one objective lens adjacent to the recording medium is provided. The objective lens has a role of converging the laser beam to a predetermined position and depth of the recording medium, but the optical characteristics such as spherical aberration differ depending on the wavelength incident on the objective lens, and is optimized for, for example, a DVD. The objective lens cannot be used as it is for a CD. For this reason, an objective lens having two focal points corresponding to the wavelength may be used. As an example of such an objective lens, a lens in which a step (diffraction grating) that causes diffraction is provided concentrically on the lens surface is known. For example, when using a DVD, transmitted light (0th order light) that is not diffracted converges at a predetermined position on the recording medium. Since the diffracted light converges at a position away from it, adverse effects as stray light can be suppressed. When the CD is used, the first-order diffracted light converges at a predetermined position on the recording medium. In this way, it is possible to record and reproduce CDs, CD-Rs, and DVDs with a single objective lens.
Japanese Patent Laid-Open No. 10-320818 Japanese Patent Laid-Open No. 10-21550 JP 2000-113488 A

  In recent years, an optical pickup device has been developed that performs recording and reproduction with higher density using blue laser light having a wavelength of about 405 nm. In this specification, a recording medium used for recording and reproduction using blue laser light having a wavelength of around 405 nm is referred to as a high-density optical disk. In order to deal with CDs, DVDs, and high-density optical discs including CD-Rs with a single pickup, it is necessary to mount laser light sources with wavelengths near 405 nm, 650 nm, and 780 nm in one pickup device. is there. In order to reduce the cost and size of the pickup device, it is preferable to make the optical path as common as possible and to make the main optical components such as the objective lens as common as possible.

  When the optical system of the pickup apparatus is shared and only one objective lens having a diffraction grating is provided, the objective lens has three focal points corresponding to each wavelength. However, the laser beams of the respective wavelengths cannot be completely converged at the corresponding focal positions. In this specification, the ratio of the laser light output that converges to the corresponding focal position to the laser light output incident on the objective lens is referred to as diffraction efficiency. Although the diffraction efficiency has a different value for each wavelength, it is impossible to obtain 100% diffraction efficiency for all three types of wavelengths. Therefore, in practice, there is a problem with what diffraction efficiency each of the laser beams of three types of wavelengths is converged to the corresponding focal positions. High-density optical discs require higher precision than other recording media such as CDs and DVDs, and require more advanced optimization, so that laser light with a wavelength of around 405 nm is effectively used. In addition, it is desirable to optimize the laser beam having a wavelength of about 405 nm by assigning a high diffraction efficiency. However, using an objective lens that prioritizes the diffraction efficiency of laser light in the vicinity of a wavelength of 405 nm, the diffraction efficiency in the vicinity of wavelengths of 650 nm and 780 nm, particularly the diffraction efficiency in the vicinity of 780 nm apart from the wavelength, is kept equal to other wavelengths. It ’s difficult. In other words, the diffraction efficiency of laser light near a wavelength of 780 nm tends to be lower than that of an optical pickup device that only supports conventional CDs and DVDs (wavelengths near 650 nm and 780 nm).

  When the diffraction efficiency decreases, the output of the laser light reaching the recording medium also decreases. In particular, when recording on a recording medium, an output larger by one digit or more than that at the time of reproduction is required, which may cause a decrease in recording performance. The required laser beam output increases as the rotational speed of the recording medium increases. Therefore, when the laser beam output near 780 nm decreases, recording on a CD at a high speed such as 24 × or 48 × speed is possible. Even using an output laser diode may not be possible.

  The present invention has been made in view of such circumstances, and an optical pickup including three laser diodes that emit laser beams having wavelengths of about 405 nm, about 650 nm, and about 780 nm and having a common objective lens. An object of the present invention is to provide an optical pickup device capable of supplying a sufficient recording / reproducing laser output to each recording medium. The present invention also provides an optical recording medium recording / reproducing method and an optical recording / reproducing apparatus capable of supplying a sufficient recording / reproducing laser output to each recording medium using such an optical pickup device. With the goal.

  An optical pickup device according to an embodiment of the present invention includes a first laser diode that emits laser light with a wavelength of 399 to 413 nm, a second laser diode that emits laser light with a wavelength of 630 to 660 nm, and a wavelength of 770 nm to A third laser diode that emits a 790-nm laser beam, an objective lens that is provided on a common optical path of the laser beams emitted from the first to third laser diodes, and a control that controls the operation of each laser diode And the ratio of the laser light output after passing through the objective lens to the output power of the third laser diode is smaller than that of the first and second laser diodes. The control unit performs recording or reproduction of the first recording medium by condensing the laser light emitted from the first laser diode onto the first recording medium via the objective lens, and performs the first recording Recording or reproduction of the second recording medium having a recording density lower than that of the medium is performed by condensing the laser light emitted from the second laser diode onto the second recording medium via the objective lens, Recording on a third recording medium having a recording density lower than that of the first and second recording media, laser light emitted from the first or second laser diode is applied to the third recording medium via the objective lens The third recording medium is reproduced by condensing the laser beam emitted from the third laser diode onto the third recording medium via the objective lens. It has been in Migihitsuji.

  The laser light emitted from the third laser diode has the smallest ratio of the laser light output after passing through the objective lens to the emitted output. For this reason, when recording is performed on the third recording medium using this, a sufficient laser output cannot be given to the third recording medium that rotates particularly at high speed. However, in this embodiment, since the recording on the third recording medium is performed using the first or second laser diode, a larger laser output can be given to the third recording medium. This is because the magnitude of the laser output is more important than the wavelength for recording on the recording medium. On the other hand, in the reproduction of the recording medium, the wavelength of the laser beam may be more important than the laser output. Thus, by using laser beams having different wavelengths for recording and reproduction, recording and reproduction on the third recording medium can be performed in the same manner as in the past.

  The objective lens may include a diffraction grating, and diffraction efficiency at wavelengths of 770 nm to 790 nm may be smaller than diffraction efficiency at wavelengths of 399 to 413 nm and 630 to 660 nm.

  An optical recording medium recording / reproducing method according to an embodiment of the present invention includes: a first laser diode that emits laser light having a wavelength of 399 to 413 nm; and a second laser diode that emits laser light having a wavelength of 630 to 660 nm; A third laser diode that emits laser light having a wavelength of 770 nm to 790 nm, and an objective lens that is provided on a common optical path of the laser light emitted from the first to third laser diodes. Recording / reproduction of an optical recording medium using an optical pickup device configured such that the ratio of the laser light output after passing through the light output to the output of the third laser diode is smaller than that of the first and second laser diodes Is the method. The present recording / reproducing method includes a step of arranging such an optical pickup device facing a recording medium that is one of the first to third recording media in descending order of recording density, and the recording medium is a first recording medium. When the medium is a medium, the first recording medium is recorded or reproduced by condensing the laser light emitted from the first laser diode onto the first recording medium via the objective lens. Is a second recording medium, the laser beam emitted from the second laser diode is condensed on the second recording medium via the objective lens, thereby recording or reproducing the second recording medium. When the recording medium is a third recording medium, the laser light emitted from the first or second laser diode is condensed on the third recording medium via the objective lens. The third recording medium is recorded, or the laser beam emitted from the third laser diode is condensed on the third recording medium via the objective lens to reproduce the third recording medium. Performing steps.

  The objective lens may include a diffraction grating, and diffraction efficiency at wavelengths of 770 nm to 790 nm may be smaller than diffraction efficiency at wavelengths of 399 to 413 nm and 630 to 660 nm.

  The third recording medium has an organic dye, and the reflectance at wavelengths of 770 nm to 790 nm may be larger than the reflectances at wavelengths of 399 to 413 nm and 630 to 660 nm.

  An optical recording / reproducing apparatus according to an embodiment of the present invention includes the above-described optical pickup device.

  As described above, according to the present invention, it is possible to provide an optical pickup device that can supply a sufficient laser output to each recording medium. Further, according to the present invention, it is possible to provide an optical recording medium recording / reproducing method and an optical recording / reproducing apparatus capable of supplying a sufficient laser output to each recording medium.

  Hereinafter, an embodiment of an optical pickup device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an optical configuration of an optical pickup device according to an embodiment of the present invention.

  The optical pickup device 1 has a first laser oscillator 3 and a second laser oscillator 4. The first laser oscillator 3 includes a first laser diode 31 that emits laser light (blue laser light) having a wavelength of 405 nm. Here, the wavelength 405 nm is an example, and the first laser oscillator 3 may emit laser light having an arbitrary wavelength in the range of 399 to 413 nm. This laser beam is used for recording and reproduction of a high density optical disk. The second laser oscillator 4 is a two-wavelength laser diode that switches and emits a laser beam for CD and a laser beam for DVD. The second laser oscillator 4 includes a second laser diode 41 that emits laser light having a wavelength of 650 nm, and a third laser diode 42 that emits laser light having a wavelength of 780 nm. The wavelength 650 nm is an example, and the second laser oscillator 4 may emit laser light having an arbitrary wavelength in the range of 630 to 660 nm. Similarly, the wavelength 780 nm is an example, and the third laser oscillator 42 may emit laser light having an arbitrary wavelength in the range of 770 to 790 nm. The configuration of the laser oscillator is not limited to this, and various combinations are possible according to the purpose of the optical pickup device. The optical pickup device 1 according to the present embodiment only needs to include three laser diodes 31, 41, and 42 each emitting laser beams having wavelengths of 399 to 413 nm, 630 to 660 nm, and 770 to 790 nm.

  The laser diodes 31, 41, and 42 are connected to a control unit (not shown). The optical pickup device 1 has identification means (not shown) for identifying whether the target recording medium is a CD, a DVD, or a high-density optical disk, and the control unit performs identification by the identification means. Based on the result, it is determined which laser diode to activate, and the selected laser diode is activated.

  On the optical path of the laser light emitted from the first laser diode 31, a first diffraction grating / half-wave plate 5 is provided. The diffraction grating is used for on-track control of laser light. The half-wave plate controls the polarization direction of the laser light, and controls reflection and transmission in the polarization beam splitter 9 described later. These are integrally provided, but they may be provided separately. Similarly, a second diffraction grating and half-wave plate 6 is provided on the optical path of the laser light emitted from the second laser oscillator 4.

  A dichroic prism 8 is provided near the intersection of the optical path of the laser light from the first diffraction grating / half-wave plate 5 and the optical path of the laser light from the second diffraction grating / half-wave plate 6. . Laser light from the first diffraction grating / half-wave plate 5 passes through the dichroic prism 8, and laser light from the second diffraction grating / half-wave plate 6 passes through the dichroic prism 8 at an angle of 90 °. reflect. As a result, the laser light emitted from any of the laser oscillators 3 and 4 travels on the same optical path after passing through the dichroic prism 8. A polarizing beam splitter 9 is provided on the optical path exiting the dichroic prism 8. The laser light emitted from the polarization beam splitter 9 is refracted by the reflection mirror 10, enters the objective lens 14 through the collimator lens 11, the liquid crystal element 12, and the quarter wavelength plate 13. As described above, the objective lens 14 is provided on the common optical path of the laser beams emitted from the first to third laser diodes 31, 41 and 42.

  The laser beam is condensed at a predetermined depth of the recording medium 19 and recording / reproduction is performed. Therefore, in order to correct the focal position in the optical path direction according to the recording medium 19 and the wavelength of the laser light, the objective lens 14 is configured to be movable in the optical path direction by an actuator (not shown). The recording medium 19 is a high-density optical disc (first recording medium), DVD (second recording medium), or CD (third recording medium), and a CD-RW (ReWritable) is included in a CD in addition to a CD-R. ) Is also included. DVD includes DVD-R, DVD-RW, and the like. CD-R has an organic dye and is optimized so as to show a sharp peak in reflectance around a wavelength of 780 nm, and the reflectance at wavelengths of 405 nm and 650 nm is very small. Laser light hardly reflects at wavelengths of 405 nm and 650 nm. The recording density of DVD is smaller than that of a high-density optical disk, and the recording density of CD is smaller than that of a high-density optical disk and DVD. At the time of recording, the laser beam is irradiated to the recording medium 19, and phase change or removal of the organic dye film is performed. During reproduction, the laser beam travels in the reverse direction from the objective lens 14 to the polarization beam splitter 9 as a reflected wave corresponding to the recording content of the recording medium 19. The reflected wave passes through the polarization beam splitter 9, enters the photodetector (light receiving element) 16 through the sensor lens 15, and the received light intensity is measured. A measurement circuit (not shown) provided outside the optical pickup device 1 identifies the recorded contents of the recording medium 19 according to the received light intensity.

The objective lens 14 includes the above-described diffraction grating. The objective lens 14 is formed so as to optimize the diffraction efficiency with respect to the laser beam having a wavelength of 405 nm emitted from the blue diode (first laser diode 31) as much as possible. In the case of a DVD, it is desirable that recording / reproduction at high speed is possible. Therefore, the objective lens 14 is formed so as to ensure as much as possible the diffraction efficiency with respect to the laser beam having a wavelength of 650 nm emitted from the second laser diode 41. As described above, as a result of giving priority to the diffraction efficiency with respect to laser beams with wavelengths of 405 nm and 650 nm, the diffraction efficiency with respect to laser beams with a wavelength of 780 nm is smaller than these. This is due to the influence of the diffraction grating and the transmissive film, but it is difficult to make the diffraction efficiency for laser light with a wavelength of 780 nm equal to the diffraction efficiency for laser light with a wavelength of 405 nm and 650 nm. It becomes smaller than the diffraction efficiency for. As a result, the ratio of the laser light output after passing through the objective lens 14 to the output power (output attenuation rate η _t shown below) of the third laser diode 42 is higher than that of the first and second laser diodes 31 and 41. Is smaller.

Table 1 is an example showing how much the laser light of each wavelength is attenuated before exiting the objective lens 14. In the table, the coupling efficiency η ₁ indicates the proportion of laser light emitted from the laser diode that enters the optical system. The transmittance η ₂ indicates the light transmittance of the entire optical system (until the objective lens 14 is emitted). The reflectance of the polarizing beam splitter 9 is 55%. In this example, the objective lens 14 is selected so as to reduce the output loss of the first and second laser diodes 31 and 41 as much as possible. As a result, the output attenuation rate η _t is the same for the first and second laser diodes 31 and 41 and is about half of that for the third laser diode 42.

  Recording / reproduction of a recording medium using such an optical pickup device 1 is performed as follows (see Table 2). The recording / reproduction shown below is controlled by the control unit 2 as described above. First, the optical pickup device 1 is arranged to face the recording medium 19. Recording or reproduction of the high-density optical disc is performed by condensing the laser beam having a wavelength of 405 nm emitted from the first laser diode 31 of the first laser oscillator 3 onto the high-density optical disc through the objective lens 14. Recording or reproduction of the DVD is performed by condensing a laser beam having a wavelength of 650 nm emitted from the second laser diode 41 of the second laser oscillator 4 onto the DVD through the objective lens 14. Recording on the CD is performed by condensing the laser light emitted from the first or second laser diode 31 or 41 onto the CD via the objective lens 14. The reproduction of the CD is performed by condensing the laser light emitted from the third laser diode 42 of the second laser oscillator 4 onto the CD via the objective lens 14.

The reason why the first or second laser diodes 31 and 41 are used for recording on the CD as described above is that the first or second laser diodes 31 and 41 are used by the third laser diode 42 as shown in Table 1. This is because also has a large output power W ₂ . Table 3 shows an example of the output of the laser beam required for recording on each recording medium 19. Table 4 shows an example of the output of the laser beam required for reproduction on each recording medium 19. In both tables, the unit is mW.

In the case of recording, the output of the laser beam is important regardless of the phase change or dye film type recording medium, and the wavelength has no significant meaning. Therefore, by using the first or second laser diode 31 or 41 having a large emission output W ₂ , the phase change of the recording medium 19 or the removal of the dye film can be more reliably performed. For example, when recording is performed on a CD using the third laser diode 42, only an output of 13 mW can be obtained, so that it is difficult to record at 4 × speed or higher from Table 3. However, if recording is performed using the second laser diode 41, an output of 27 mW can be obtained, so that recording at 8 × speed is possible. Since the first laser diode 31 can also output 15 mW, recording at 4 × speed is possible. However, if sufficient laser output can be obtained even with the third laser diode 42 due to the configuration of the optical system and the rotation speed of the recording medium 19, it is possible to record on the CD using the third laser diode 42. It is.

  On the other hand, in the case of reproduction, it can be seen from Table 4 that a large laser beam output is not required as in recording. Rather, there are cases where sufficient reflectivity cannot be obtained unless the laser light has a wavelength of around 780 nm as in the case of CD-R, and the wavelength is an important factor. Further, when laser light having a wavelength of 405 nm or 650 nm is irradiated during reproduction, the recording medium 19 has a low reflectance in these wavelength bands, that is, a high absorptance, so that excessive energy is concentrated on the recording medium 19 and recorded. Data may be destroyed. Therefore, it is appropriate to use the third laser diode 42 for CD reproduction.

  Next, an optical recording / reproducing apparatus using the optical pickup apparatus 1 of the present embodiment will be described. FIG. 2 is a block diagram schematically showing the configuration of an optical recording / reproducing apparatus using the optical pickup device of this embodiment.

  The optical recording / reproducing apparatus 101 includes the above-described optical pickup apparatus 1, a spindle motor 112 for rotating the recording medium 19, a controller 113 for controlling the operation of the spindle motor 112 and the optical pickup apparatus 1, and the optical pickup apparatus 1. A laser drive circuit 114 that supplies a laser drive signal and a lens drive circuit 115 that supplies a lens drive signal to the optical pickup device 1 are provided.

  The controller 113 includes a focus servo tracking circuit 116, a tracking servo tracking circuit 117, and a laser control circuit 118. When the focus servo tracking circuit 116 is activated, the information recording surface of the rotating recording medium 19 is focused, and when the tracking servo tracking circuit 117 is activated, the eccentricity signal track of the recording medium 19 is detected. Thus, the spot of the laser beam is in an automatic tracking state. The focus servo tracking circuit 116 and the tracking servo tracking circuit 117 are respectively provided with an auto gain control function for automatically adjusting the focus gain and an auto gain control function for automatically adjusting the tracking gain. The laser control circuit 118 is a circuit that generates a laser drive signal supplied from the laser drive circuit 114, and generates an appropriate laser drive signal based on the recording condition setting information recorded on the recording medium 19. Do. Note that the focus servo tracking circuit 116, the tracking servo tracking circuit 117, and the laser control circuit 118 do not need to be circuits incorporated in the controller 113, and may be separate components from the controller 113. Furthermore, these need not be physical circuits, and may be software executed in the controller 113.

  As described above, according to the optical pickup device of the present embodiment, three laser diodes that emit laser beams having wavelengths of 405 nm, 650 nm, and 780 nm can be provided with the main optical components as common as possible. For this reason, the cost and size of the pickup device can be suppressed. In addition, high-speed recording / reproduction of CDs and DVDs can be performed in the same manner as in the past while supporting recording / reproduction of high-density optical disks.

It is a conceptual diagram which shows the optical system of the optical pick-up apparatus which concerns on one Embodiment of this invention. 1 is a block diagram schematically showing a configuration of an optical recording / reproducing apparatus using an optical pickup device of an embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 2 Control part 3 1st laser oscillator 31 1st laser diode 4 2nd laser oscillator 41 2nd laser diode 42 3rd laser diode 5 1st diffraction grating and 1/2 wavelength plate 6 Second diffraction grating / half wavelength plate 8 Dichroic prism 9 Polarizing beam splitter 10 Reflecting mirror 11 Collimator lens 12 Liquid crystal element 13 1/4 wavelength plate 14 Objective lens 15 Sensor lens 16 Photo detector (light receiving element)
DESCRIPTION OF SYMBOLS 19 Recording medium 101 Optical recording / reproducing apparatus 112 Spindle motor 113 Controller 114 Laser drive circuit 115 Lens drive circuit 116 Focus servo tracking circuit 117 Tracking servo tracking circuit 118 Laser control circuit

Claims (6)

A first laser diode that emits laser light having a wavelength of 399 to 413 nm;
A second laser diode that emits laser light having a wavelength of 630 to 660 nm;
A third laser diode that emits laser light having a wavelength of 770 nm to 790 nm;
An objective lens provided on a common optical path of laser beams emitted from the first to third laser diodes;
A control unit for controlling the operation of each laser diode;
With
The ratio of the laser light output after passing through the objective lens to the output power is configured such that the third laser diode is smaller than the first and second laser diodes,
The controller performs recording or reproduction of the first recording medium by condensing the laser light emitted from the first laser diode onto the first recording medium via the objective lens, Recording or reproduction of a second recording medium having a recording density lower than that of the first recording medium is performed by collecting laser light emitted from the second laser diode onto the second recording medium via the objective lens. Recording on a third recording medium having a recording density lower than that of the first and second recording media is performed, and laser light emitted from the first or second laser diode is used as the objective. The third recording medium is condensed by condensing the third recording medium through a lens, and the laser beam emitted from the third laser diode is used as the objective lens. It is adapted performed by condensing the third recording medium via the optical pickup device.   The optical pickup device according to claim 1, wherein the objective lens includes a diffraction grating, and diffraction efficiency at wavelengths of 770 nm to 790 nm is smaller than diffraction efficiency at wavelengths of 399 to 413 nm and 630 to 660 nm. A first laser diode that emits laser light having a wavelength of 399 to 413 nm, a second laser diode that emits laser light having a wavelength of 630 to 660 nm, and a third laser diode that emits laser light having a wavelength of 770 nm to 790 nm; An objective lens provided on a common optical path of the laser beams emitted from the first to third laser diodes, and the ratio of the laser beam output after passing through the objective lens to the emission output is An optical pickup device configured such that the third laser diode is smaller than the first and second laser diodes, and the recording medium is one of the first to third recording media in descending order of recording density. A step of disposing them facing each other,
When the recording medium is the first recording medium, the first recording medium is configured to focus the laser light emitted from the first laser diode on the first recording medium via the objective lens. When the recording medium is recorded or reproduced, and the recording medium is a second recording medium, a laser beam emitted from the second laser diode is transmitted through the objective lens to the second recording medium. When the recording medium is a third recording medium, the laser light emitted from the first or second laser diode is emitted when the second recording medium is recorded or reproduced. The third recording medium is recorded by being condensed on the third recording medium through the objective lens, or the laser beam emitted from the third laser diode is used as the objective lens. And performing playback of the third recording medium by converging the third recording medium through a lens,
An optical recording medium recording / reproducing method comprising:   4. The optical recording medium according to claim 3, wherein the third recording medium has an organic dye, and the reflectance at wavelengths of 770 nm to 790 nm is larger than the reflectances at wavelengths of 399 to 413 nm and 630 to 660 nm. Recording and playback method.   The optical recording medium according to claim 3 or 4, wherein the objective lens includes a diffraction grating, and diffraction efficiency at wavelengths of 770 nm to 790 nm is smaller than diffraction efficiency at wavelengths of 399 to 413 nm and 630 to 660 nm. Method.   An optical recording / reproducing apparatus comprising the optical pickup device according to claim 1.

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