JP4176070B2 - Optical disc pickup control apparatus and optical disc pickup control method - Google Patents

Description

  The present invention relates to an optical disk pickup control device and an optical disk pickup control method, and in particular, a single CD-type disk, a DVD-type disk, a BD (Blu-ray Disc) -type disk, and an HD-DVD (High-Density DVD). The present invention relates to an optical disk pickup control apparatus and a control method thereof for recording or reproducing a plurality of types of optical disks such as high-density DVD) disks.

  Conventionally, in an optical disk drive device, that is, an optical disk pickup control device, a spindle motor that controls the rotation of the optical disk, the focused light is focused on the recording / reproducing layer of the optical disk, and can be moved to any track (address) It is made up of an optical pickup. In addition, the optical pickup includes an actuator unit that moves the objective lens up and down, left and right, and always controls the movement of the light spot to a desired position on the optical disk. Also, the optical system unit for creating the light spot and the actuator unit are housed in one housing and are called an optical pickup. FIG. 3 shows a schematic configuration of a conventional optical disk drive control device.

  As shown in FIG. 3, in the conventional optical disk drive control device, the optical disk 33 is rotationally controlled by a spindle motor 32 and controlled by an optical pickup horizontal drive motor 36 via a guide rail 35 that moves in the horizontal direction. The pickup 31 is moved horizontally to an arbitrary track (address) position on the optical disk 33, and the optical system unit for generating a light spot is moved up and down in the vertical direction by the actuator unit 34 housed in the housing of the optical pickup 31 to The focal point of the beam 37 is formed on the recording / reproducing layer of the optical disc 33.

  In recent years, the recording density of optical discs has increased rapidly. For this purpose, the light spot connected to the recording / reproducing layer needs to be extremely small. The size of the light spot is proportional to (λ / NA) and sin (θ). Here, λ is the wavelength of the laser light, NA is the aperture of the objective lens (Numerical Aperture), and θ is the angle between the effective diameter of the objective lens and the focal point. In general, in order to reduce the light spot so as to enable high-density recording on an optical disc, the aperture NA has to be increased if the wavelength λ of the laser light becomes a short wavelength to the limit.

Recently, in order to realize high-density recording, a BD (Blu-ray Disc) system having a laser wavelength of 405 nm and an aperture NA of 0.85 has appeared as a laser beam used for an optical disc. The recording / reproducing layer of this BD disc is formed about 0.1 mm inside the optical disc surface. In this case, the distance between the optical disc and the objective lens top (referred to as a working distance WD) is extremely close to 1 mm from a comma number of millimeters (0.times.mm x: integer).
Furthermore, in an HD-DVD (High Density DVD) standard optical disk such as HD-DVD-ROM that has appeared as another method for high-density recording optical disks, the laser wavelength is the same as that of the BD method described above. Although it is 405 nm, the aperture NA is about 0.6, and the recording / reproducing layer of the HD-DVD disc is 0.6 mm inside from the surface of the optical disc as in the case of the conventional DVD disc.

  On the other hand, the conventional DVD disc has a laser beam wavelength of 650 nm, an aperture NA of 0.6, and the recording / reproducing layer of the DVD disc is 0.6 mm inside the optical disc surface. In the conventional CD disc, the wavelength of the laser beam is 780 nm, the aperture NA is 0.4 to 0.5, and the recording / reproducing layer of the CD disc is 1.2 mm on the inner side of the optical disc surface.

  In a conventional optical disk drive control device, information recording or reproduction corresponding to both a DVD disk and a CD disk can be performed by a single pickup, commonly called a two-wavelength pickup using a wavelength selection filter or the like. In addition, the distance between the top of the objective lens and the optical disk can be adjusted to an appropriate working distance WD of about 1 mm, and a DVD / CD drive device capable of driving both disks can be configured.

  However, as BD discs compatible with short-wave blue-violet lasers and HD-DVD compatible optical discs using the same wavelength appear on the market as in recent years, conventional DVD discs and CD discs Furthermore, there is a very difficult problem to record or reproduce four types of optical discs with one pickup by adding recording and reproduction of a BD disc or HD-DVD disc. For example, for a BD pickup, it is necessary to sharply narrow the light beam with an aperture NA of 0.85, and to focus on the recording / reproducing layer only 0.1 mm inside from the optical disk surface, and the light spot size. In order to decrease the working distance, the working distance WD needs to be a very small value.

  In order to perform recording / reproduction on the HD-DVD disc by mounting an HD-DVD disc of a system different from the BD disc in the optical disc drive control device with the working distance WD as a small value as a BD pickup. In addition, if the objective lens is brought closer to the optical disc side in order to focus on the inner recording / reproducing layer of 0.6 mm from the surface of the optical disc, the objective lens comes into contact with the optical disc. Etc. will be damaged.

  On the contrary, when set as an HD-DVD pickup, the aperture NA of the objective lens is 0.6, and the recording / reproducing layer of the HD-DVD disc is the same as that of the conventional DVD disc. The laser wavelength is 405 nm which is the same as that for BD. Therefore, the working distance WD can also take a value close to 1 mm as the objective lens. However, for HD-DVD discs, with a working distance WD set to a value close to 1 mm, a BD disc of a different system from the HD-DVD disc is mounted on the optical disc drive controller and recorded on the BD disc. When performing reproduction, if the objective lens is moved away from the optical disk side in order to focus on the recording / reproducing layer 0.1 mm inside from the surface of the optical disk, the movable area on the lower side of the actuator section (side away from the optical disk) is usually Insufficient working distance WD cannot be expanded.

  Also, since the aperture NA differs for HD-DVD discs and BD discs, such as 0.6 and 0.85, it is desirable to change the distance between the optical disc and the objective lens. It is impossible to focus on the position of the recording / reproducing layer. Therefore, a means for changing the aperture NA for HD-DVD discs and BD discs is newly required. That is, for example, when an HD-DVD drive for recording / playback of an HD-DVD disc is installed and a BD disc is mounted, the aperture NA is different as described above, so that for an HD-DVD disc If the aperture NA of the objective lens remains unchanged, there is a problem that the recording / reproducing layer of the BD disc cannot be focused correctly.

  Further, from the viewpoint of the aberration of the light beam spot, the spherical aberration increases in proportion to {(the third power of NA) / λ}, while the coma aberration increases to {(the fourth power of NA) / λ}. Increase proportionally. Here, λ is the laser wavelength. Therefore, as the aperture NA becomes larger and the wavelength λ becomes shorter, it is necessary to surely perform aberration correction so as to correctly form a minute light spot only on the recording / reproducing layer of the optical disc. Also, since both BD discs and HD-DVD discs use laser light of the same wavelength of 405 nm, simply using a wavelength selection filter or dichroic beam splitter, BD discs and HD-DVD discs It is difficult to separate the optical system to be used due to the difference.

  Due to the above-described problems, it is very difficult to construct each optical disc of BD, HD-DVD, conventional DVD, and CD with a single pickup. From the viewpoints of cost reduction, miniaturization, thinning, high reliability, and ease of use of the control device, it is very important to configure it with one pickup and one or two objective lenses.

  Japanese Patent Application Laid-Open No. 2004-158118 “Optical Head Device and Optical Information Recording / Reproducing Device” disclosed in Patent Document 1 uses a plurality of objective lenses, a conventional DVD standard, CD standard optical disc, and blue An optical pickup capable of recording and reproducing a next-generation optical disk (the above-mentioned BD disk) using violet laser light is described. That is, a first optical system that emits irradiation light having a wavelength of 405 nm and a second optical system that emits irradiation light having a wavelength of 650 nm or 780 nm are provided, and the irradiation light having a wavelength of 405 nm is applied to the thickness of the protective layer by the first objective lens. The irradiated light having a wavelength of 650 nm or 780 nm is focused on the next-generation standard optical disc having a thickness of 0.1 mm, and the protective layer has a thickness of 0.6 mm or a CD standard of 1.2 mm by the second objective lens. It is configured to be focused on an optical disk.

Further, in Japanese Patent Laid-Open No. 2003-296959 “Wavelength Selective Aperture Limiting Element, Wavelength Selective Beam Splitter, and Optical Pickup Device Having the Same” disclosed in Japanese Patent Laid-Open No. 2003-296959, CD-type, DVD-type and BD-type optical disks A technique is disclosed in which three types of optical discs having different information recording densities and protective layer thicknesses are recorded / reproduced with laser beams having different wavelengths using one objective lens. That is, as a wavelength-selective aperture limiting filter that changes the aperture NA of the objective lens by three types of wavelengths of 405 nm, 650 nm, and 780 nm, the first filter and the second filter are arranged in the vicinity of the objective lens, The first filter includes an annular wavelength selection filter having an aperture NA of 0.85 that transmits only laser light having a wavelength of 405 nm, and a transmitted wavefront phase matching film that transmits all three types of laser light. The filter of FIG. 5 includes an annular wavelength selection filter having an aperture NA of 0.6, which transmits laser light with wavelengths of 405 nm and 650 nm, and a transmitted wavefront phase matching film that transmits all three types of laser light. Optical disk pickup control apparatus for recording / reproducing CD-type, DVD-type, and BD-type optical disks with only one objective lens whose aperture NA is controlled by It is configured.
JP 2004-158118 A JP 2003-296959 A

  However, in Patent Document 1 and Patent Document 2, only the technology relating to the configuration of the optical system of the optical pickup and the method for controlling the aperture NA is used, and only when recording / reproduction is performed using laser beams having different wavelengths. It is limited to. In other words, there is no description of any driving method for controlling the distance between the optical disk and the objective lens, which is indispensable for an optical disk pickup control apparatus that records and reproduces a plurality of optical disks, and 1 in one optical disk pickup control apparatus. Using only one optical pickup, it is possible to read and write information on a plurality of types of optical discs such as BD discs, HD-DVD discs, DVD discs, and CD discs using laser light having a plurality of wavelengths including the same wavelength. For this reason, there is no mention at all about the determination of the type of the mounted optical disk that needs to be carried out, the selection of a pickup optical system, a specific driving method, or the setting of the movable range of the objective lens.

  The present invention has been made in view of such circumstances, and devised a method for discriminating the type of an optical disk loaded, a method for selecting / switching a pickup optical system, or a method for setting a movable range of an objective lens. An optical system using one or two objective lenses is configured by only one optical pickup in one optical disk pickup control device, and a BD disk, an HD-DVD disk, a DVD disk, a CD disk Information recording and reproduction on a plurality of types of optical discs are not possible.

The first technical means is for Blu-ray standard discs (hereinafter abbreviated as BD discs), HD-DVD standard discs (hereinafter abbreviated as HD-DVD discs), and plural types of optical discs such as DVD discs and CD discs. In an optical disk pickup control apparatus capable of recording or reproducing information, it corresponds to the type of light source that emits each laser beam having a wavelength of 405 nm, 650 nm, and 780 nm in one optical pickup and the type of optical disk to be mounted. And a filter unit for narrowing the light flux of the transmitted laser beam, a first objective lens corresponding to the BD disc, and a second objective lens corresponding to the other HD-DVD disc, DVD disc and CD disc. Switch control between two objective lenses, the first objective lens and the second objective lens Utotomoni, as a default state and an actuator unit for performing control to move the first objective lens or the second objective lens, showing the standard state so as to change the distance between the optical disc, the 405nm as the laser wavelength Using a light source, the laser beam from the first objective lens having a thickened luminous flux and an aperture NA of 0.85 in the filter unit is connected as a small light spot to the recording / reproducing layer 0.1 mm inward from the optical disk surface. When a focus servo error signal output from the optical pickup is checked when an optical disc is loaded and an S-curve focus servo error signal is observed. The optical disc loaded is discriminated as a BD disc, and the optical system of the optical pickup is set as the default. When an information recording or reproducing operation is performed using an optical system for recording and reproducing a BD disc that is left in the state, on the other hand, when an S-curve focus error signal is not observed, the loaded optical disc is HD. -An optical disc pickup control device that discriminates between a DVD disc, a DVD disc, and a CD disc.

According to a second technical means, in the optical disk pickup control apparatus according to the first technical means, when an S-curve focus error signal is not observed in the BD disc recording / reproducing optical system, a laser wavelength is set. While using the light source of 405 nm, the actuator unit changes to an optical system using the second objective lens, and moves the second objective lens to the position near 0.6 mm outside the optical disk surface, A focus servo error output from the optical pickup by rotating the optical disk at a predetermined constant speed with the aperture narrowed until the aperture NA of the second objective lens becomes 0.6 by the filter unit. And the track cross signal are checked, and the focus servo error signal of the S curve is observed, On the other hand, if it is observed that the cycle of the track cross signal is shorter than a predetermined threshold, the mounted optical disc is discriminated as an HD-DVD disc, and the second objective lens having an aperture NA of 0.6. Is controlled by a focus servo error signal and a track cross signal by using an optical system for recording / reproducing HD-DVD discs, in which the laser beam from the optical disc is connected to the recording / reproducing layer 0.6 mm inside from the surface of the optical disc as a minute light spot. Turned on to perform information recording or reproducing operation. On the other hand, if it is not observed that the period of the track cross signal is shorter than the threshold value or if the focus error signal of the S curve is not observed, it is attached. The disc is discriminated as a DVD disc or a CD disc.

According to a third technical means, in the optical disk pickup control apparatus according to the second technical means, the cycle of the track cross signal is shorter than the predetermined threshold in the optical system for recording and reproducing the HD-DVD disc. Is not observed, or when the focus error signal of the S curve is not observed, and when it is observed that the period of the track cross signal is longer than the threshold, the mounted optical disk is a DVD system. The disc is discriminated and switched from a light source having a laser wavelength of 405 nm to 650 nm, and the laser beam from the second objective lens having an aperture NA of 0.6 is connected as a light spot from the optical disc surface to the recording / reproducing layer 0.6 mm inside. Using a DVD-based disc recording / playback optical system, focus servo error signal and track cross signal When the information recording / reproducing operation is performed with the control according to (3) turned on, and the focus servo error signal of the S curve is not observed, the mounted optical disc is discriminated as a CD disc and the laser wavelength is set. CD-based disc recording that switches from a light source of 405 nm to a light source of 780 nm, and combines the laser beam from the second objective lens with an aperture NA reduced to 0.45 as a light spot from the surface of the optical disc to the recording / reproducing layer 1.2 mm inside. The information recording or reproducing operation is performed by turning on the control based on the focus servo error signal and the track cross signal using the reproducing optical system.

A fourth technical means is the optical disk pickup control device according to any one of the first to third technical means, wherein the filter unit includes the light source having a wavelength of 405 nm and the first objective lens or the second objective lens. Between the first objective lens and the second objective lens, and an aperture mechanism capable of switching the aperture NA of the first objective lens or the second objective lens to a desired value, and each of wavelengths 405 nm, 650 nm, and 780 nm. A wavelength selection filter that is disposed between the light source and the first objective lens or the second objective lens and that selects a laser beam that is transmitted according to a wavelength, and corrects the aberration of the laser beam that irradiates the optical disc. An aberration correction mechanism is provided.

According to a fifth technical means, in the optical disk pickup control device according to the fourth technical means, the aperture mechanism sets the aperture NA of the first objective lens or the second objective lens to 0.6, 0.85. The wavelength selection filter switches the aperture NA of the first objective lens or the second objective lens to either 0.45, 0.6, or 0.85. It can be set.

The sixth technical means is for Blu-ray standard disc (hereinafter abbreviated as BD disc), HD-DVD standard disc (hereinafter abbreviated as HD-DVD disc), and plural types of optical discs such as DVD disc and CD disc. The first objective lens for condensing a laser beam having a wavelength of 405 nm for a BD disc and the lasers having wavelengths of 405 nm, 650 nm and 780 nm for other HD-DVD discs, DVD discs and CD discs, respectively. In an optical disc pickup control method capable of recording or reproducing information using two objective lenses, a second objective lens that collects light , the aperture NA is set to 0.85 as a default state indicating a standard state. A laser beam having a wavelength of 405 nm from the first objective lens is The optical system for recording / reproducing BD discs connected to the recording / reproducing layer of 0.1 mm on the side as a minute light spot is set, and the focus servo error signal output when the optical disc is mounted is checked. When the focus servo error signal of the curve is observed, the mounted optical disc is discriminated as a BD disc, and the optical system for recording and reproducing the BD disc in which the optical system of the optical pickup is left in the default state. On the other hand, when the S-curve focus error signal is not observed, the mounted optical disc is either an HD-DVD disc, a DVD disc or a CD disc. It is characterized by an optical disk pickup control method for determining whether or not.

A seventh technical means is the optical disc pickup control method according to the sixth technical means, wherein when the focus error signal of the S curve is not observed in the BD disc recording / reproducing optical system, the laser wavelength is The optical system using the second objective lens is changed to an optical system using the second objective lens, and the second objective lens is moved outside the optical disk surface to a position near 0.6 mm, and the aperture NA of the second objective lens is changed. The aperture is squeezed until the value reaches 0.6, the optical disk is rotated at a predetermined constant speed, the output focus servo error signal and the track cross signal are checked, and the S curve focus servo is checked. When an error signal is observed and the period of the track cross signal is observed to be shorter than a predetermined threshold The mounted optical disc is discriminated as an HD-DVD disc, and the laser beam from the second objective lens having an aperture NA of 0.6 is connected as a small light spot to the recording / reproducing layer 0.6 mm inside from the optical disc surface. Using the optical system for recording / reproducing HD-DVD discs, the control by the focus servo error signal and the track cross signal is turned on to perform the information recording or reproducing operation, while the cycle of the track cross signal is the threshold value In the case where it is not observed to be shorter than this, or when the focus error signal of the S curve is not observed, the mounted optical disc is discriminated as a DVD disc or a CD disc.

According to an eighth technical means, in the optical disk pickup control method according to the seventh technical means, the cycle of the track cross signal is shorter than the predetermined threshold in the optical system for recording and reproducing the HD-DVD disc. Is not observed, or when the focus error signal of the S curve is not observed, and when it is observed that the period of the track cross signal is longer than the threshold, the mounted optical disk is a DVD system. The disc is discriminated as a disc, the laser wavelength is switched from 405 nm to 650 nm, and the laser beam from the second objective lens having an aperture NA of 0.6 is connected as a light spot from the optical disc surface to the inner 0.6 mm recording / reproducing layer. By using a focus servo error signal and track cross signal When the information is recorded or reproduced with the control turned on, and the focus servo error signal of the S curve is not observed, the mounted optical disc is discriminated as a CD disc and the laser wavelength is 405 nm. For CD-type disc recording / reproduction in which the laser beam from the second objective lens whose aperture NA is reduced to 0.45 is coupled as a light spot from the surface of the optical disc to the inner recording / reproduction layer of 1.2 mm. Using an optical system, control by a focus servo error signal and a track cross signal is turned on, and an information recording or reproducing operation is performed.

  According to the present invention constituted by any one of the technical means as described above, only one pickup in one optical disc pickup control apparatus is used, and two objective lenses are recorded and reproduced according to the type of optical disc. Configure a flexible optical system that can be used for switching, or configure an optical system that uses only one objective lens, and each of the BD disc, HD-DVD disc, DVD disc, and CD disc Recording or reproduction can be performed on the optical disk, and a multipurpose optical disk pickup control apparatus can be configured. As a result, the optical disk pickup control device can be reduced in size, thickness, and reliability, can be made simple and easy to use, and can be provided as a more inexpensive device.

Embodiments of an optical disk pickup control device according to the present invention will be described below with reference to the drawings.
As shown in FIG. 3, the conventional optical disk pickup control apparatus generally includes an optical pickup drive mechanism comprising an optical pickup horizontal drive motor 36 and a guide rail 35, a pickup 31, a spindle motor 32 that controls the rotation of the optical disk 33, and The circuit board is not shown. In the case of a conventional optical disk such as a CD disk (Compact Disk) or a DVD disk (Digital Versatile Disk), the working is the distance between the optical disk 33 and the objective lens top in the optical pickup 31. Usually, the distance WD (Working Distance) is set to about (1 to 1.5) mm, and even if an optical disk with a slight surface shake is mounted on the optical disk pickup control device, the optical disk 33 and the optical disk The optical components of the pickup control device did not come into contact with each other and were not damaged. However, in recent years, it is necessary to make the light spot minute for high-density recording, and as described above in the background art, the working distance WD is allowed only a very close distance from a few millimeters (mm) to 1 mm. The number of optical disk pickup control devices is increasing.

FIG. 1 shows an embodiment of an optical disk pickup control apparatus according to the present invention made in view of such a situation. FIG. 1 is a block diagram showing an example of an embodiment relating to the configuration of the optical disk pickup control device according to the present invention.
An optical disc A 3A in FIG. 1 is a BD disc having a recording / reproducing layer 3A ₁ at 0.1 mm from the surface of the optical disc A 3A, and the optical disc B 3B is 0.6 mm from the surface of the optical disc B 3B. Either an HD-DVD disc or a DVD disc having a recording / reproducing layer 3B ₁ or a CD disc (not shown) having a recording / reproducing layer 1.2 mm from the surface of the optical disc B 3B. Show. Both the optical disc A 3A and the optical disc B 3B have a disc thickness of 1.2 mm. FIG. 1 is shown based on an optical system in the case of recording / reproduction of the optical disc A 3A, that is, a BD disc.

  In FIG. 1, reference numeral 1A denotes a blue-violet laser hologram unit, which is a light source that emits laser light having a wavelength of 405 nm for BD discs and HD-DVD discs. A light receiving element OPIC (Optical IC) that generates a phase difference hologram, a servo signal, an RF signal, a wobble signal, and the like is provided. Reference numeral 1B denotes a red laser hologram unit, which is a light source that emits laser light having a wavelength of 650 nm for a DVD-based disk, and has a configuration substantially the same as the above-described 405 nm hologram laser. Reference numeral 1C denotes an infrared 780 nm laser hologram unit, which is a light source that emits a laser beam having a wavelength of 780 nm for a CD-based disc, and has a configuration substantially the same as that of the 405 nm hologram laser described above.

  Reference numerals 4A, 4B, and 4C denote collimating lenses disposed in the vicinity of the laser hologram units of the blue-violet laser hologram unit 1A, the red laser hologram unit 1B, and the infrared 780 nm laser hologram unit 1C, respectively. Reference numerals 5A and 5B denote a dichroic beam splitter that transmits blue-violet laser light and reflects red laser light, and a dichroic beam splitter that transmits blue-violet laser light and red laser and reflects infrared 780 nm laser light. Reference numerals 2A and 2B denote an objective lens A for a BD optical disc A 3A and an objective lens B for an HD-DVD system, DVD system, or CD optical disk B 3B, respectively.

  That is, in the configuration diagram shown in FIG. 1, one of the two types of objective lens A 2A and objective lens B 2B is used as an appropriate objective lens depending on the type of optical disk to be mounted. Selected. That is, the objective lens A 2A is selected as an objective lens for BD, and the objective lens B 2B is selected as any objective lens for HD-DVD, DVD, or CD. The two types of objective lens A 2A and objective lens B 2B are configured to be rotationally supported by the actuator unit as shown by the thick arrow in FIG. 1, and the selected objective lens is supplied from the laser light source. The laser beam is supported on the optical axis.

  In addition, the actuator unit 9 determines the interval between the objective lens A 2A for BD and the optical disc, and the interval between any objective lens B 2B for HD-DVD, DVD, and CD and the optical disc, respectively. According to the type of the optical disc, in the case of a BD disc, the light beam incident from the objective lens A 2A having an aperture NA of 0.85 is inward from the surface of the BD disc. In order to form a light spot on the recording / reproducing layer located at 0.1 mm, and in the case of an HD-DVD system or DVD system disk, the light beam incident from the objective lens B 2B having an aperture NA of 0.6 is An objective lens having an aperture NA of 0.45 so that a light spot is formed on the recording / reproducing layer located 0.6 mm inside from the surface, or in the case of a CD-based disc. The position of each objective lens is moved and controlled so that the light beam incident from B 2B forms a light spot on the recording / reproducing layer located 1.2 mm inward from the surface of the CD disc. .

  Next, the operation of the optical system of the optical disk pickup control apparatus will be described in the case where the optical disk loaded in the optical disk pickup control apparatus is the optical disk B 3B and is a CD disk. Here, when a CD-type disc is loaded, the objective lens B 2B for the optical disc B 3B is rotated as shown by the thick arrow and is supported on the optical axis. 9, the light beam having a wavelength of 780 nm incident from the objective lens B 2B having an aperture NA of 0.45 is driven and controlled so as to form a light spot on the recording / reproducing layer 1.2 mm inside from the surface of the CD disk.

  The laser beam for the CD disk emitted from the hologram unit 1C for infrared 780 nm laser is reflected by the dichroic beam splitter 5B via the collimating lens 4C, and a direction conversion mirror (not shown) and the wavelength selection filter 8 are reflected. Then, the light is focused by the objective lens B 2B that is rotatably supported on the optical axis, and a light spot is formed at the position of the recording / reproducing layer disposed 1.2 mm inside from the surface of the CD system disc.

  The reflected light reflected by the reflective layer of the CD disc passes through the reverse optical path, is reflected by the dichroic beam splitter 5B, and enters the infrared 780 nm laser hologram unit 1C via the collimator lens 4C. The light is diffracted by the hologram element of the hologram unit 1C for infrared 780 nm laser, is incident on the light receiving element portion, and a plurality of light receiving elements OPIC generate signals necessary for recording and reproduction such as servo signals and RF signals.

  Next, the operation of the optical system of the optical disk pickup control apparatus will be described when the optical disk loaded in the optical disk pickup control apparatus is the optical disk B 3B and is a DVD-type disk. For DVD-based discs, as in the case of CD-based discs, the objective lens B 2B for the optical disc B 3B is rotated as indicated by the thick arrow and is supported on the optical axis. The actuator unit 9 drives and controls the light beam having a wavelength of 650 nm incident from the objective lens B 2B having an aperture NA of 0.6 so as to form a light spot on the recording / reproducing layer 0.6 mm inside from the surface of the DVD disk. Yes.

  The laser beam for the DVD disk emitted from the red laser hologram unit 1B is reflected by the dichroic beam splitter 5A via the collimator lens 4B, and the aberration correction mechanism 7 for correcting the aberration of the light beam spot, the dichroic beam splitter. 5B, passing through a direction conversion mirror (not shown) and a wavelength selection filter 8 and condensed by an objective lens B 2B which is rotatably supported on the optical axis, and is 0.6 mm inside from the surface of the DVD disk. A light spot is formed at the position of the recording / reproducing layer disposed at the position.

  The reflected light reflected by the reflective layer of the DVD disk passes through the reverse optical path, is reflected by the dichroic beam splitter 5A, is incident on the red laser hologram unit 1B via the collimator lens 4B, and is then received by the red laser. The light is diffracted by the hologram element of the hologram unit 1B, is incident on the light receiving element portion, and a plurality of light receiving elements OPIC generate signals necessary for recording and reproduction such as servo signals, wobble signals, and RF signals.

  Of the two dichroic beam splitters 5A and 5B shown in FIG. 1, the dichroic beam splitter 5A has a property of transmitting laser light having a wavelength shorter than 650 nm and reflecting laser light having a wavelength longer than 650 nm, On the other hand, the dichroic beam splitter 5B has a property of transmitting laser light having a wavelength shorter than 780 nm and reflecting laser light having a wavelength longer than 780 nm.

  Next, the operation of the optical system of the optical disk pickup control apparatus will be described in the case where the optical disk loaded in the optical disk pickup control apparatus is the optical disk A 3A and is a BD disk. For the BD disc, unlike the CD disc, the objective lens A 2A for the optical disc A 3A is supported on the optical axis as shown in FIG. Drive control is performed so that a light beam having a wavelength of 405 nm incident from the objective lens A 2A having an aperture NA of 0.85 forms a light spot on the recording / reproducing layer 0.1 mm inside from the surface of the BD disc. Further, the blue-violet laser aperture 6 disposed between the collimating lens 4A and the dichroic beam splitter 5A is used to transmit laser light that is transmitted depending on whether the mounted optical disc is a BD disc or an HD-DVD disc. An aperture mechanism that narrows the luminous flux. In the case of a BD disc, the aperture stop is opened so that the aperture NA of the objective lens A2A is 0.85.

  The laser light emitted from the blue-violet laser hologram unit 1A for the BD disc or the HD-DVD disc passes through the collimating lens 4A through the blue-violet laser aperture 6 with the aperture stop opened. The optical beam passes through the dichroic beam splitter 5A, the aberration correction mechanism 7, the dichroic beam splitter 5B, the direction conversion mirror (not shown), and the wavelength selection filter 8 while maintaining a thick beam diameter. Is focused by the objective lens A 2A supported by the optical disc, and a minute light spot is formed at the position of the recording / reproducing layer disposed at a position of 0.1 mm inside from the surface of the BD disc.

  The reflected light reflected by the reflective layer of the BD disc passes through the optical path opposite to that described above, passes through the dichroic beam splitter 5A, and enters the blue-violet laser hologram laser unit 1A via the collimator lens 4A. Signals necessary for recording / reproducing servo signals, wobble signals, RF signals, etc. are generated by a plurality of light receiving elements OPIC by being diffracted by the hologram element of the blue-violet laser hologram laser unit 1A and incident on the light receiving element unit. The

  Next, the operation of the optical system of the optical disk pickup control apparatus will be described in the case where the optical disk loaded in the optical disk pickup control apparatus is the optical disk B 3B and is an HD-DVD disk. For the HD-DVD disc, as in the case of the CD disc, the objective lens B 2B for the optical disc B 3B is rotated as indicated by the thick arrow and is supported on the optical axis. Thus, the actuator unit 9 causes the light beam having a wavelength of 405 nm incident from the objective lens A 2A having an aperture NA of 0.6 to form a light spot on the recording / reproducing layer 0.6 mm inside from the surface of the HD-DVD disc. Drive controlled. Further, the blue-violet laser aperture 6 disposed between the collimating lens 4A and the dichroic beam splitter 5A has an aperture stop of an objective lens B2B having an aperture NA of 0, contrary to the case of a BD disc. It is made into the state narrowed down to 6.

  The laser beam for the BD disc or the HD-DVD disc emitted from the blue-violet laser hologram unit 1A passes through the collimating lens 4A through the blue-violet laser aperture 6 in which the aperture stop is narrowed. The light is passed through after being narrowed down to a narrow beam diameter, via a dichroic beam splitter 5A, an aberration correction mechanism 7, a dichroic beam splitter 5B, a direction changing mirror (not shown), and a wavelength selection filter 8. The light beam is focused by the objective lens B 2B which is supported on the axis and formed into a minute light spot at the position of the recording / reproducing layer disposed at a position 0.6 mm inside from the surface of the HD-DVD disc.

  The reflected light reflected by the reflective layer of the HD-DVD disc passes through the reverse optical path, passes through the dichroic beam splitter 5A, and enters the hologram laser unit 1A for blue-violet laser through the collimator lens 4A. Then, the light is diffracted by the hologram element of the blue-violet laser hologram laser unit 1A, is incident on the light receiving element portion, and a plurality of light receiving elements OPIC generates signals necessary for recording / reproducing servo signals, wobble signals, RF signals, and the like. Generated.

  The wavelength selection filter 8 is a filter that selects and changes the size of the transmitted light beam according to the wavelength of the incident laser light, and in the order of blue-violet laser light, red laser light, and infrared 780 nm laser light, It is designed so that the transmitted light flux is appropriately increased. The optical disk pickup control apparatus shown in FIG. 1 has a configuration in which one of two objective lenses A 2A and B 2B can be rotatably supported on the optical axis by an actuator unit, and an aperture 6 for blue-violet laser and aberrations BD discs, HD-DVD discs, DVD discs, and CD discs can be recorded or reproduced by a single optical disc pickup control device by appropriately arranging the correction mechanism 7 and the wavelength selection filter 8. The example which implement | achieves the multi-purpose recording device or reproducing | regenerating apparatus to be shown.

  Further, in the optical disk pickup control apparatus shown in FIG. 1, in order to determine the type of the mounted optical disk, each of the blue-violet laser hologram unit 1A, the red laser hologram unit 1B, and the infrared 780 nm laser hologram unit 1C. Servo signals (focus servo error signal, track cross signal) generated by the light receiving element OPIC are used.

  That is, as a default state indicating the standard state of the optical disk pickup control device, a laser beam having a wavelength of 405 nm emitted from the blue-violet laser hologram unit 1A is set in a BD optical system for recording / reproducing a BD disk. Is used to open the aperture of the blue-violet laser aperture 6 and focus the light on the inner surface 0.1 mm above the surface of the optical disc by the objective lens A 2A having an aperture NA of 0.85. Set in the system. In the default state, when it is observed that the focus servo error signal generated by the light receiving element OPIC of the blue-violet laser hologram laser unit 1A draws a clear S curve, the mounted optical disk is Discriminated as a BD disc, using the laser wavelength of 405 nm in the default state, and using an optical system for recording / reproducing a BD disc using an objective lens A 2A with an aperture NA of 0.85, Records or reproduces information.

  On the other hand, when the focus servo error signal generated by the light receiving element OPIC of the blue-violet laser hologram laser unit 1A is not observed to draw a clear S curve in the default state, it is mounted. It is determined that the optical disc was not a BD disc.

  Thus, next, in order to determine whether or not the HD-DVD disc is loaded, the laser beam with a wavelength of 405 nm from the blue-violet laser hologram unit 1A is used as it is, and the blue-violet laser aperture 6 is used. The aperture NA is reduced to 0.6, the actuator unit switches to an optical system using the objective lens B 2B, and the actuator unit 9 moves and controls the objective lens B 2B so that it is outside the optical disk surface. The focus servo error signal and the track generated by the light receiving element OPIC of the blue-violet laser hologram unit 1A are obtained by rotating the optical disk at a predetermined constant speed in a state where the optical disk is moved to a position near 0.6 mm. Check for cross signal.

  When it is observed that the focus servo error signal generated by the light receiving element OPIC of the blue-violet laser hologram unit 1A has a clear S-curve and the cycle of the track cross signal is shorter than a predetermined threshold value In this case, it is determined that the mounted optical disc is an HD-DVD disc, and the focus servo error signal and the track are set in the above-described optical system for recording / playback of the HD-DVD disc. The control by the cross signal, that is, the tracking servo signal is turned on, and the information recording or reproducing operation is performed.

  On the other hand, when it is observed that the period of the track cross signal generated by the light receiving element OPIC of the blue-violet laser hologram unit 1A is longer than a predetermined threshold, the mounted optical disk is a DVD disk. The light source is switched from the blue-violet laser hologram unit 1A having a laser wavelength of 405 nm to the red laser hologram unit 1B having a wavelength of 650 nm for a DVD disk, and is used for recording / reproducing a DVD disk as described above. With the optical system set, the control by the focus servo error signal and the track cross signal is turned on to perform information recording or reproducing operation. When laser light having a wavelength of 650 nm is used, the aperture NA of the objective lens B 2B is set to 0.6 by the wavelength selection filter 8.

  If it is not observed that the focus servo error signal generated by the light receiving element OPIC of the blue-violet laser hologram unit 1A has a clear S curve, the mounted optical disk is a CD disk. The light source is switched from the blue-violet laser hologram unit 1A with the laser wavelength of 405 nm to the infrared 780 nm laser hologram unit 1C with the wavelength of 780 nm for the CD disk, and the recording of the CD disk as described above is performed. With the reproduction optical system set, the control by the focus servo error signal and the track cross signal is turned on, and information recording or reproduction operation is performed. When laser light having a wavelength of 780 nm is used, the aperture NA of the objective lens B 2B is set to 0.45 by the wavelength selection filter 8.

  Next, an embodiment different from the embodiment shown in FIG. 1 of the optical disk pickup control apparatus according to the present invention will be described with reference to FIG. FIG. 2 is a block diagram showing an example different from FIG. 1 as an embodiment relating to the configuration of the optical disk pickup control device according to the present invention. In the embodiment shown in FIG. 2, unlike the case of FIG. 1, only one objective lens is configured, and the actuator for controlling the movement of the objective lens is also intended for only one objective lens. As in the case of FIG. 1, all of the above-described BD discs, HD-DVD discs, DVD discs, and CD discs can be handled. Each of the optical system elements shown in FIG. 2 has substantially the same function as the optical system element shown in FIG. 1 except for the objective lens C 2C and the actuator unit 9 ′ that controls the movement of the objective lens C 2C. The same reference numerals as those in FIG.

  The operation of the optical system for recording or reproduction of each optical disk such as a BD disc, HD-DVD disc, DVD disc, and CD disc in FIG. 2 is substantially the same as in FIG. 1, and detailed description thereof is omitted. However, unlike the case of FIG. 1, the objective lens C 2C consisting of only one is always configured to be supported on the optical axis of the laser light emitted from the laser light source, and the actuator unit. When the position of the objective lens C 2C is driven and controlled by 9 ', the objective lens C 2C arranged very close to the optical disc does not contact the optical disc, and the objective lens C 2C and optical system parts are not damaged. As described above, the movable distance of the objective lens C2C is limited.

  In the optical disk pickup control apparatus shown in FIG. 2, the objective lens C2C needs to be disposed closest to the optical disk surface among the above-mentioned four types of optical disks as a standard state immediately after power-on or when an optical disk is mounted. The case of an HD-DVD disc is applied, and a laser beam having a wavelength of 405 nm incident from an objective lens C2C having an aperture NA of 0.6 is recorded 0.6 mm inside from the surface of the HD-DVD disc. When forming a fine light spot correctly at the position of the reproduction layer, the objective lens C 2C that can secure about 1 mm as the working distance WD indicating the distance between the optical disk surface and the top of the objective lens C 2C is used. It is said.

  When the mounted optical disc is the optical disc B 3B and is an HD-DVD disc, as described with reference to FIG. 1, the BD disc emitted from the blue-violet laser hologram unit 1A or HD- The laser beam for the DVD disc passes through the collimating lens 4A and the blue-violet laser aperture 6 in which the aperture is narrowed so that the aperture NA of the objective lens C2C is 0.6. The light is condensed by the objective lens C2C via the dichroic beam splitter 5A, the aberration correction mechanism 7, the dichroic beam splitter 5B, the direction changing mirror (not shown) and the wavelength selection filter 8, and the surface of the HD-DVD disc. A minute light spot is formed at the position of the recording / reproducing layer disposed at a position 0.6 mm inside from the center. The position of the objective lens C2C is determined by the actuator unit 9 'so that a light beam having a wavelength of 405 nm emitted from the objective lens C2C having an aperture NA of 0.6 is very small on the recording / reproducing layer 0.6 mm from the surface of the HD-DVD disc. The drive is controlled so as to form a light spot.

  In this case, the position of the objective lens C2C driven and controlled by the actuator unit 9 'is set so that the working distance WD is about 1 mm as described above. That is, in the case of an HD-DVD disc, the actuator unit 9 'takes into consideration ± 0.3 mm of the surface deflection of the optical disc so that the working distance WD falls within the range of 0.7 to 1.3 mm. In addition, it is sufficient if the top position of the objective lens C2C from the surface of the HD-DVD disc can be driven and controlled with a range of 0.7 to 1.3 mm as a movable distance for position adjustment.

  As described above, in the standard state set for the HD-DVD disc, a laser beam having an aperture NA of 0.85 is slightly inward from the optical disc surface while using the same wavelength 405 nm as that for the HD-DVD disc. When a BD disc that needs to be focused on the position of the recording / reproducing layer of 0.1 mm is mounted, the actuator unit 9 'sets the position of the objective lens C2C to at least 0 from the standard state for HD-DVD. It is necessary to control the drive so that the reference point is moved to a position retracted from the .5 mm optical disk. Further, taking into account ± 0.3 mm of the surface deflection of the optical disk and errors, the actuator unit 9 ′ is driven so that a movable range of about ± 0.7 mm can be secured around the moved reference point. It is desirable to control.

  That is, in the case of a BD disc, the actuator unit 9 'can reliably focus on the position of the recording / reproducing layer 0.1 mm inside from the surface of the optical disc, and the working distance WD is 0.8 to 2. The top position of the objective lens C2C from the surface of the BD disc is 0.7 to 2.2 mm in consideration of switching of the optical system from the HD-DVD disc to the BD disc so that the range of 2 mm can be covered. It is sufficient to drive and control this range as a movable distance for position adjustment.

  In a standard state set for an HD-DVD disc, the laser beam having an aperture NA of 0.6 is focused on the position of the recording / reproducing layer having an inner diameter of 0.6 mm from the surface of the optical disc using a wavelength of 650 nm as a light source. The objective lens C 2C from the surface of the DVD disc is mounted so that the working distance WD can cover the range of 0.8 to 2.2 mm when the DVD disc that needs to be mounted is mounted, as in the case of the BD disc. As in the case of the BD disc, it is sufficient if the top position of the drive can be controlled to be within the range of 0.7 to 2.2 mm as the movable distance for position adjustment.

  In a standard state set for an HD-DVD disc, a laser beam having an aperture NA of 0.45 is focused on the position of the recording / reproducing layer 1.2 mm inside from the optical disc surface with a wavelength of 780 nm as a light source. When the CD disc that needs to be mounted is mounted, the top position of the objective lens C2C from the surface of the CD disc is 0.7 or more so that the working distance WD can cover the range of 1.0 to 2.4 mm. It is sufficient if the range of 2.4 mm can be driven and controlled as a movable distance for position adjustment.

  That is, in the case of the configuration shown in FIG. 2, in the case of a standard HD-DVD disc, the actuator unit 9 'moves the top position of the objective lens C2C from the optical disc surface to a movable range of 0.7 to 1.3 mm. In the case of a BD disc and a DVD disc, the top position of the objective lens C2C from the surface of the optical disc is within a movable range of 0.7 to 2.2 mm. In the case of a CD disc, the surface of the optical disc The top position of the objective lens C2C is limited so that the drive control is possible only within a movable range of 0.7 to 2.4 mm.

  By setting the movable range of the actuator unit 9 'as described above, even when not only HD-DVD discs but also other types of optical discs are mounted, the light spot is correctly positioned at the position of the recording / reproducing layer of the desired optical disc. In addition to being able to form an optical disk, no matter what kind of optical disk is mounted, the optical disk abuts on the optical system components of the optical disk pickup control device, causing problems in the optical system, It can be prevented from being destroyed.

  The numerical value of the movable range of the objective lens C2C by the actuator unit 9 'described above is an example, and is not limited to such a movable range. The important point here is that in the case of a BD disc, as well as in the case of a DVD disc or CD disc, rather than in the case of an HD-DVD disc that needs to be arranged closest to the objective lens C2C. The objective lens C 2C is controlled to move so that the top position of the objective lens C 2C moves away from the surface of the optical disc. Further, in the case of a BD disc, the DVD disc or the CD disc is of course HD-DVD. It is important to make the aperture NA of the objective lens C2C larger than in the case of the system disk, and to appropriately perform aberration correction corresponding to the large aperture NA and a short wavelength.

It is a block diagram which shows an example of embodiment regarding the structure of the optical disk pick-up control apparatus which concerns on this invention. It is a block diagram which shows the example from which the embodiment regarding the structure of the optical disk pick-up control apparatus which concerns on this invention differs. It is a block diagram which shows the outline | summary of the conventional optical disk drive control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A ... Holographic unit for blue-violet laser, 1B ... Hologram unit for red laser, 1C ... Hologram unit for infrared 780 nm laser, 2A ... Objective lens A, 2B ... Objective lens B, 2C ... Objective lens C, 3A ... Optical disc A, 3B: Optical disk B, 3A ₁ , 3B ₁ ... Recording / reproducing layer, 4A, 4B, 4C ... Collimating lens, 5A, 5B ... Dichroic beam splitter, 6 ... Blue-violet laser aperture, 7 ... Aberration correction mechanism, 8 ... Wavelength selection Filters 9, 9 '... Actuator part, 31 ... Optical pickup, 32 ... Spindle motor, 33 ... Optical disk, 34 ... Actuator part, 35 ... Guide rail, 36 ... Horizontal drive motor for optical pickup, 37 ... Light beam.

Claims (8)

Recording and playback of information on multiple types of optical discs such as Blu-ray discs (hereinafter abbreviated as BD discs), HD-DVD discs (hereinafter abbreviated as HD-DVD discs), DVD discs, and CD discs In an optical disk pickup control device that can be performed,
A light source that emits laser beams having wavelengths of 405 nm, 650 nm, and 780 nm, respectively, in one optical pickup;
A filter unit that narrows the luminous flux of the laser beam that passes through in accordance with the type of optical disk to be mounted;
Two objective lenses, a first objective lens corresponding to a BD disc and a second objective lens corresponding to other HD-DVD disc, DVD disc and CD disc;
An actuator unit that performs switching control between the first objective lens and the second objective lens and performs control to move the first objective lens or the second objective lens so as to change a distance between the first objective lens and the second objective lens; With
As a default state indicating a standard state, a light source having a laser wavelength of 405 nm is used, and the laser beam from the first objective lens with an aperture NA of 0.85 is set to be 0 inward from the optical disk surface. Set to a BD disc recording / reproducing optical system that is connected to a 1 mm recording / reproducing layer as a minute light spot,
When an optical disc is mounted, the focus servo error signal output from the optical pickup is checked. If an S-curve focus servo error signal is observed, the mounted optical disc is determined as a BD disc, Information recording or reproduction was performed using an optical system for recording / reproducing BD discs with the optical system of the optical pickup remaining in the default state, while no focus error signal of the S curve was observed. In this case, the optical disk pickup control apparatus discriminates whether the mounted optical disk is an HD-DVD disk, a DVD disk or a CD disk. In the optical disk pickup control device according to claim 1, when an S-curve focus error signal is not observed in the optical system for recording and reproducing the BD disk, the light source having a laser wavelength of 405 nm is used as it is. The actuator unit is changed to an optical system using the second objective lens, and the second objective lens is moved outside the optical disk surface to a position near 0.6 mm, and the second objective lens is moved by the filter unit. With the aperture squeezed until the aperture NA reaches 0.6, the optical disk is rotated at a predetermined constant speed, and the focus servo error signal and the track cross signal output from the optical pickup are checked. The focus servo error signal of the S curve is observed and the track cross signal Is observed to be shorter than a predetermined threshold value, the mounted optical disc is discriminated as an HD-DVD disc, and the laser beam from the second objective lens having an aperture NA of 0.6 is used as the optical disc surface. Information recording using a focus servo error signal and track cross signal control, using an optical system for recording / reproducing HD-DVD discs that is connected to a recording / reproducing layer 0.6 mm inward as a minute light spot. Alternatively, when a reproduction operation is performed, on the other hand, when it is not observed that the cycle of the track cross signal is shorter than the threshold value or when the focus error signal of the S curve is not observed, the mounted optical disc is a DVD-type disc or An optical disk pickup control device characterized by being discriminated as a CD-type disk . 3. The optical disk pickup control device according to claim 2, wherein it is not observed that the cycle of the track cross signal is shorter than the predetermined threshold in the optical system for recording and reproducing the HD-DVD disc, or the S curve. When the focus error signal is not observed, and it is observed that the period of the track cross signal is longer than the threshold, the mounted optical disc is discriminated as a DVD disc and the laser wavelength is 405 nm. To a 650 nm light source, and a laser beam from the second objective lens having an aperture NA of 0.6 is connected as a light spot from the optical disk surface to an inner 0.6 mm recording / reproducing layer. To turn on the control based on the focus servo error signal and the track cross signal, and It performs the recording or reproducing operation, also, the S curve
If no focus servo error signal is observed, the mounted optical disk is discriminated as a CD disk, the laser wavelength is switched from 405 nm to 780 nm, and the aperture NA is reduced to 0.45. 2. Control by focus servo error signal and track cross signal using CD optical disc recording / playback optical system that connects laser light from the objective lens to the 1.2mm inner recording / playback layer from the optical disc surface. An optical disk pickup control device for recording or reproducing information . 4. The optical disk pickup control device according to claim 1 , wherein the filter unit is arranged between the light source having a wavelength of 405 nm and the first objective lens or the second objective lens and transmits the laser light. A diaphragm mechanism capable of switching the aperture NA of the first objective lens or the second objective lens to a desired value, the light sources having wavelengths of 405 nm, 650 nm, and 780 nm, and the first objective lens or the A wavelength selection filter that is arranged between the second objective lens and that selects a laser beam that is transmitted according to the wavelength; and an aberration correction mechanism that corrects the aberration of the laser beam applied to the optical disc. An optical disk pickup control device. 5. The optical disk pickup control device according to claim 4 , wherein the aperture mechanism can set the aperture NA of the first objective lens or the second objective lens by switching between 0.6 and 0.85, An optical disc pickup control , wherein the wavelength selection filter can switch and set the aperture NA of the first objective lens or the second objective lens to either 0.45, 0.6, or 0.85 apparatus. For BD discs for Blu-ray discs (hereinafter abbreviated as BD discs), HD-DVD discs (hereinafter abbreviated as HD-DVD discs), and DVD and CD discs. A first objective lens that condenses laser light having a wavelength of 405 nm and a second objective that condenses laser light having wavelengths of 405 nm, 650 nm, and 780 nm as other HD-DVD discs, DVD discs, and CD discs, respectively. In an optical disk pickup control method capable of recording or reproducing information using two objective lenses, ie, an objective lens,
  As a default state indicating a standard state, a BD system in which a laser beam having a wavelength of 405 nm from the first objective lens having an aperture NA of 0.85 is connected as a minute light spot from the optical disk surface to a recording / reproducing layer 0.1 mm inward. It is set in the optical system for recording / reproducing the disc, the focus servo error signal output when the optical disc is loaded is checked, and when the focus servo error signal of the S curve is observed, the loaded optical disc Discriminates the disc as a BD disc, and uses the BD disc recording / reproducing optical system in which the optical system of the optical pickup remains in the default state to perform information recording or reproducing operation, while the S curve If no focus error signal is observed, the mounted optical disc is an HD-DVD disc or DVD disc. Or optical disk pickup control method characterized by determining that any of the CD system disc. 7. The optical disc pickup control method according to claim 6, wherein when an S-curve focus error signal is not observed in the BD disc recording / reproducing optical system, the laser wavelength remains at 405 nm, and the second objective lens is used. The second objective lens is moved to the outside of the optical disk surface to a position near 0.6 mm, and the aperture is reduced until the aperture NA of the second objective lens becomes 0.6. In this state, the optical disk is rotated at a predetermined constant speed, the output focus servo error signal and the track cross signal are checked, the focus servo error signal of the S curve is observed, and the track cross If it is observed that the signal period is shorter than a predetermined threshold, the loaded optical disk is HD. Disc discriminating from DVD discs, HD-DVD disc recording in which the laser beam from the second objective lens having an aperture NA of 0.6 is connected as a small light spot from the optical disc surface to the recording / reproducing layer 0.6 mm inside. Using the optical system for reproduction, the control by the focus servo error signal and the track cross signal is turned on to perform information recording or reproduction operation, while it is observed that the cycle of the track cross signal is shorter than the threshold value. If the focus error signal or if the S-curve did was not observed, the loaded optical disk is an optical disk pickup control method characterized by determining the DVD system disk or CD-based disc. 8. The optical disk pickup control method according to claim 7, wherein it is not observed that the cycle of the track cross signal is shorter than the predetermined threshold in the optical system for recording / reproducing the HD-DVD disk or the S curve. When the focus error signal is not observed, and it is observed that the period of the track cross signal is longer than the threshold, the mounted optical disc is discriminated as a DVD disc and the laser wavelength is 405 nm. The optical system for recording / reproducing a DVD disc is used to switch the laser beam from the second objective lens having an aperture NA of 0.6 to a recording / reproducing layer 0.6 mm inside from the surface of the optical disc as a light spot. Turn on the control by the focus servo error signal and track cross signal to record information. Alternatively, when a reproduction operation is performed and no S-curve focus servo error signal is observed, the mounted optical disc is determined to be a CD-type disc, the laser wavelength is switched from 405 nm to 780 nm, and the aperture NA is changed. Focus servo error by using an optical system for recording / reproducing a CD-based disk, in which the laser beam from the second objective lens, which has been reduced to 0.45, is connected as a light spot from the surface of the optical disk to the recording / reproducing layer 1.2 mm inside. An optical disk pickup control method , wherein information is recorded or reproduced by turning on control by a signal and a track cross signal .

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