JP2005267839A - Optical-disk drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep stable light emitting quantity of a light emitting element when recording or reproduction is performed at a plurality of numerical apertures. <P>SOLUTION: An optical-disk drive device includes light emitting elements 1a, 12a, a beam splitter 3 branching out-going luminous flux of these light emitting elements 1a, 12a to first luminous flux and second luminous flux, a photodetector 4 detecting front light branched by the bean splitter 3, an aperture restriction member 5, and a controller 50 controlling out-going light quantity of the light emitting elements 1a, 12a using a signal obtained from the photodetector 4. The photodetector 4 has has a circular first detection area receiving inner luminous flux of the first luminous flux and a ring-shaped second detection area receiving outer luminous flux of the first luminous flux. The controller 50 performs light quantity control on the basis of received light quantity of the first detection area and the second detection area at the time of large numerical aperture and performs light quantity control on the basis of received light quantity of the first detection area at the time of small numerical aperture. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical disk drive apparatus that records or / and reproduces information by irradiating an optical disk with light.

  2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Document 1, an optical disk drive device has been proposed in which information can be recorded / reproduced with two numerical apertures (NA).

  FIG. 15 shows a conventional optical disk drive described in Patent Document 1. As shown in FIG. 15, the optical disc driving apparatus includes a plurality of light emitting / receiving units 131 and 132, a polarization beam splitter 135 that is an optical path matching unit, a collimator lens 139, a half mirror 143 that is a beam splitting unit, The optical detector 144 and the objective lens 140 are provided. The light receiving / emitting unit 131 includes a light emitting element 133 and a first light receiving element 161, and the light receiving / emitting unit 132 includes a light emitting element 134 and a first light receiving element 162. The photodetector 144 includes a second light receiving element 151. The light emitting element 133 and the light emitting element 134 are not driven simultaneously, and only one of them is driven to emit light.

  When the optical disk (recording medium) 141 is driven, the light emitting element 133 is driven. At this time, the light beam 136 emitted from the light emitting element 133 passes through the polarization beam splitter 135 and is converted into substantially parallel light by the collimator lens 139. The light beam 136 converted into substantially parallel light is condensed on the optical disk 141 by the objective lens 140. The reflected light from the optical disk 141 returns to the light emitting / receiving unit 131 by following the original optical path. In the light receiving / emitting unit 131, the reflected light is guided to the first light receiving element 161 by the hologram element (not shown) and received.

  When the optical disk (recording medium) 142 is driven, the light emitting element 134 is driven. At this time, the light beam 137 emitted from the light emitting element 134 is reflected by the polarization beam splitter 135 and bent at a right angle, and passes through the same optical path as the light beam 136. The reflected light beam 137 is converted into substantially parallel light by the collimator lens 139 and condensed on the optical disk 142 by the objective lens 140. The reflected light from the optical disk 142 follows the original optical path and returns to the light emitting / receiving unit 132. In the light receiving / emitting unit 132, the reflected light is guided to the first light receiving element 162 and received.

  The half mirror 143 reflects a part of the parallel light from the collimating lens 139 and transmits the other part. Both the reflected light of the light beam 136 and the reflected light of the light beam 137 by the half mirror 143 are received as front light by the single second light receiving element 151 in the detector 144. The signal output from the detector 144 is fed back to the drive circuit of the light emitting element to keep the output of the light emitting element 133 or the light emitting element 134 constant.

In this way, a signal is recorded on the optical disc 141 or the optical disc 142, or a signal recorded on the optical disc 141 or the optical disc 142 is reproduced.
Japanese Patent Laid-Open No. 10-222864 (FIG. 8)

  However, in the conventional configuration, as shown in FIG. 16, the light beam detected by the second light receiving element 151 is only the central part of the light beams 136 and 137. When the light emission pattern of 133, 134 is changed, the proportional relationship between the light emission amount of the light emitting elements 133, 134 and the light reception amount of the second light receiving element 151 is lost, so that there is a problem that accurate light amount control cannot be performed. It was.

  Further, when recording / reproducing with a plurality of numerical apertures in one optical disk drive device, even if the second light receiving element 151 is set to detect the total light amount of a light beam with a certain numerical aperture, other numerical apertures are used. Since a part of the light beam or an unnecessary light beam is detected, there is a problem that accurate light amount control cannot be performed.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and enables an optical disc drive apparatus capable of dealing with a plurality of numerical apertures to maintain a stable light emission amount of a light emitting element with respect to light amount control at each numerical aperture. With the goal.

  In order to achieve the above-mentioned object, the present invention is based on the assumption that an optical disk driving device capable of operating at a numerical aperture corresponding to each of a plurality of optical disks, and a light beam emitted from the light source as a first light beam and a second light beam. A branching element that branches into the first detector, a first detector that receives the first light beam branched by the branching element, and a controller that controls the amount of light emitted from the light source in accordance with the amount of light received by the first detector. A second detector that receives the second light flux after being reflected by the optical disc, the first detector receiving a first detection area that receives an inner light flux of the first light flux, and an outer side of the first light flux. At least one second detection region that receives a light beam, and the controller controls a light emission amount of the light source based on a light reception amount of the first detection region; Receiving one detection area and the second detection area Based on the amount is configured to be switched to the second control state for controlling the extraction intensity of the light source.

  In this configuration, when the numerical aperture is set to a small value, the controller controls the amount of light emitted from the light source based on the amount of light received by the first detection region that receives only the inner light beam of the first light beam. The controller determines the emission amount of the light source based on both the received light amount of the first detection region that receives the inner light beam of the first light beam and the received light amount of the second detection region that receives the outer light beam of the first light beam. Control. In this way, by changing the detection area according to the numerical aperture, it becomes possible to detect the total light amount of the first light flux according to the numerical aperture at any numerical aperture, and thus the optical disk drive that can handle a plurality of numerical apertures. In the apparatus, accurate light quantity control can be performed for each numerical aperture.

  An aperture limiting member that allows the second light beam branched by the branch element to pass is disposed between the branch element and the optical disc, and the aperture limiting member includes at least a first aperture state and the first aperture state. It is good also as a structure which has so that it can switch to the 2nd opening state which allows the said 2nd light beam of larger diameter to pass through.

  In this configuration, the numerical aperture corresponding to the second light beam incident on the optical disc can be set in a plurality of stages by the aperture limiting member.

  A collimating lens is provided between the light source and the branch element to convert a light beam traveling from the light source to the branch element into a parallel light beam, and the first detection region passes through the aperture limiting member in the first opening state. The second light beam that is formed in a circular shape having substantially the same diameter as the second light beam, the second detection region is provided around the first detection region, and passes through the aperture limiting member in the second opening state. It may be formed in an annular shape having an outer diameter that is substantially the same as the outer diameter.

  In this configuration, since a parallel light beam is incident on the branch element, the first light beam and the second light beam that are emitted from the branch element and the first light beam that is incident on the first detector have the same diameter. Become. As a result, the opening diameter of the opening limiting member in the first opening state and the first detection area may be substantially the same diameter, and the opening diameter of the opening limiting member in the second opening state and the outer diameter of the second detection area Should be approximately the same diameter. Therefore, reliable total light quantity detection can be easily performed for each numerical aperture.

  The aperture limiting member is configured to perform an aperture limiting operation to adjust a beam diameter of the second light beam, and the controller is coupled to the aperture limiting operation of the aperture limiting member in the first control state. And the second control state may be switched.

  In this configuration, the control state of the controller can be reliably matched according to each numerical aperture, and the emitted light amount control by the light source can be ensured.

  A plurality of light sources that emit light having different wavelengths are provided as the light source, and an aperture limiting member that allows the second light flux branched by the branch element to pass between the branch element and the optical disc is disposed. The aperture limiting member is configured by a filter that adjusts the diameter of the second light flux that passes through the filter based on the wavelength of the second light flux, and the controller determines whether one of the light sources emits light. The control state may be switched.

  With this configuration, it is possible to reliably control the amount of emitted light by the light source while simplifying the configuration of the aperture limiting member.

  As the light source, a plurality of light sources that emit light having different wavelengths may be provided, and the controller may be configured to switch a control state depending on which of the light sources emits.

  In this configuration, since the detection region is selected according to the wavelength of the light beam received by the first detector, when a light beam having a different wavelength is used for each numerical aperture, the light amount detection corresponding to each numerical aperture is performed. Can be performed with high accuracy.

  As the light source, a first light source and a second light source that emits light having a wavelength shorter than that of the first light source are provided, and the first detection region is emitted from the first light source and branched by the branch element. The second detection region may be configured to receive the first light beam emitted from the second light source and branched by the branch element. Good.

  In this configuration, in a configuration in which two light sources having different wavelengths are used, the first detector can detect the total light amount of the light beam even if the light beam diameter of the short wavelength light beam emitted from the second light source is increased. Even when a plurality of numerical apertures are set, it is possible to perform light amount control with high accuracy.

  The numerical aperture may be set to any two of about 0.45, about 0.6, and about 0.85.

  With this configuration, as one optical disk drive device, a numerical aperture 0.45 system represented by a CD (Compact Disc), a numerical aperture 0.6 system represented by a DVD (Digital Versatile Disc), and a BD ( When any two of the systems having a numerical aperture of 0.85 typified by Blu-ray Disc) are combined, a signal for controlling the amount of light corresponding to each numerical aperture can be obtained. it can.

  The light source includes a first light source, a second light source that emits light having a shorter wavelength than the first light source, and a third light source that emits light having a shorter wavelength than the second light source, The first detector receives a first detection region that receives an inner light beam of the first light beam, a second detection region that receives an outer light beam of the first light beam, and a first detection region that receives an outermost light beam of the first light beam. A first control state in which the controller controls an emission amount of the first light source based on a light reception amount of the first detection region, and the first detection region and the second detection region. A second control state in which the amount of light emitted from the second light source is controlled based on the amount of light received in the region; and the third light source based on the total amount of light received in the first detection region, the second detection region, and the third detection region. It may be configured to be switchable to a third control state for controlling the amount of light emitted.

  In this configuration, in a configuration in which three light sources having different wavelengths are used, even if the diameter of the light beam is increased as the wavelength of the light beam emitted from the light source is shortened, the total amount of light of the light beam is detected by the first detector. Thus, even when a plurality of numerical apertures are set, highly accurate light amount control can be performed.

  The numerical aperture may be set to about 0.45, about 0.6, and about 0.85.

  According to this configuration, when one optical disk drive device is configured with a numerical aperture 0.45 system, a numerical aperture 0.6 system, and a numerical aperture 0.85 system, the numerical aperture depends on each numerical aperture. A signal for controlling the amount of light can be obtained.

  If the plurality of light sources are provided in separate packages, general-purpose light sources can be used.

  The first detection area and the second detection area may be formed concentrically.

  In this configuration, a signal for controlling the amount of light corresponding to the numerical aperture can be obtained simply by configuring the first detector with a detection area pattern corresponding to the inner diameter of the first luminous flux and the outer diameter of the first luminous flux. Therefore, the apparatus configuration can be simplified.

  A diffractive element is disposed between the branch element and the first detector. The diffractive element diffracts the inner light flux toward the first detection region, and the outer light flux And a second diffractive portion that diffracts toward the two detection regions.

  In this configuration, since the inner light beam and the outer light beam of the first light beam branched by the branch element can be separately diffracted and divided, the degree of freedom of the detection area pattern of the first detector can be increased. . In addition, the position of the first detector can be easily adjusted.

  A condensing element may be disposed between the diffractive element and the first detector.

  In this configuration, the light beam divided by the diffractive element according to the numerical aperture can be condensed on the first detector by the condensing element to obtain a signal for controlling the amount of light.

  An aperture limiting member that allows the first light beam branched by the branch element to pass is disposed between the branch element and the first detector, and the aperture limiting member is at least in a first opening state. The second light beam having a diameter larger than that of the one opening state and the second opening state that allows a light beam having substantially the same diameter to pass through may be switchable.

  In this configuration, the beam diameter of the first light beam branched by the branch element is adjusted by the aperture limiting member, so that it can be adjusted so that the entire light amount of the first light beam can be received in each detection region.

  The branch element may be constituted by a hologram element. With this configuration, components can be integrated.

  According to the optical disk drive device of the present invention, it is possible to cope with a plurality of numerical apertures and to maintain a stable light emission amount of the light emitting element with respect to each numerical aperture.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing an optical disc driving apparatus according to Embodiment 1 of the present invention. FIG. 2 is a diagram showing the shape of the photodetector and the arithmetic circuit. As shown in FIG. 1, the optical disk drive device is configured so that two numerical apertures (a high numerical aperture and a low numerical aperture) can be set, and a light emitting element 1a that is a light source, a collimating lens 2, The main components are a beam splitter 3, which is a branch element, a photodetector 4, which is a first detector, an aperture limiting member 5, an objective lens 6, a photodetector 9, which is a second detector, and a controller 50. As an element. In this optical disk drive, a high numerical aperture is set when an optical disk 7a as a recording medium is loaded, and a low numerical aperture is set when an optical disk 7b is loaded.

  The light emitting element 1a is mounted on the package 1 and constitutes a light emitting unit that emits a light beam. The collimating lens 2 is disposed between the light emitting element 1a and the beam splitter 3, and converts the light beam 10 emitted from the light emitting element 1a and directed to the beam splitter 3 into substantially parallel light. The beam splitter 3 branches the light beam 10 converted into substantially parallel light, and has a reflecting surface 3a. On the reflection surface 3a of the beam splitter 3, the light beam 10 is branched into a first light beam guided to the photodetector 4 and a second light beam guided to the objective lens 6 (optical disks 7a and 7b as recording media).

  The photodetector 4 detects a first light beam reflected by the reflecting surface 3 a of the beam splitter 3 among the parallel light beams 10.

  The aperture limiting member 5 is disposed between the beam splitter 3 and the objective lens 6. The aperture limiting member 5 adjusts so as to limit the diameter (diameter) of the second light beam that passes through the reflecting surface 3a of the beam splitter 3 and enters the objective lens 6 among the parallel light beam 10. The first opening state and the second opening state can be switched to two opening states. The first aperture state is an aperture state when a low numerical aperture is set, and the outer diameter light flux of the second light flux is shielded to allow the diameter of the second light flux 10b to pass as the diameter φB. In FIG. 1, the second light beam 10b is indicated by a solid line. On the other hand, the second opening state is an opening state when a high numerical aperture is set, and allows the diameter of the second light beam 10a to pass as the diameter φA. In FIG. 1, the second light beam 10a is indicated by a broken line.

  The opening limiting member 5 is configured to switch the opening state by controlling the voltage applied to the liquid crystal element. The switching of the opening state of the opening limiting member 5 is performed by the controller 50 as described later. The aperture limiting member 5 has a configuration in which a light shielding member having openings with an inner diameter φA and an inner diameter φB is inserted into and removed from the optical path of the second light beam, or a light shielding with an opening whose inner diameter is variable between φA and φB. It is good also as a structure which switches with an opening restriction | limiting by comprising with a member. In this case, the controller 50 controls the driving of the aperture limiting member.

  The objective lens 6 is for condensing a light beam on the optical disks 7a and 7b. The optical disk 7a is a recording medium on which recording / reproduction is performed when the second light beam 10a having a diameter φA is condensed when the aperture limiting member 5 is in the second aperture state (high numerical aperture). The optical disc 7b is a recording medium on which recording / reproduction is performed with the second light beam 10b having a diameter φB condensed when the aperture limiting member 5 is in the first aperture state (low numerical aperture).

  A detection lens 8 is disposed between the branch element 3 and the photodetector 9. The detection lens 8 condenses the light beam reflected by the optical discs 7 a and 7 b on the photodetector 9. The photodetector 9 is for detecting servo signals and RF signals.

  As shown in FIG. 2, the photodetector 4 has a first detection region 4b and a second detection region 4a. Both the detection areas 4a and 4b constitute a light detection unit which is configured to be substantially concentric with the light detector 4. The first detection region 4b is configured by a circular region having an outer diameter substantially the same as the diameter φB of the second light flux at the time of a low numerical aperture. As a result, the first light flux at the low numerical aperture or the inner light flux of the first light flux at the high numerical aperture is incident on the first detection region 4b. On the other hand, the second detection region 4a is formed on the outer periphery side of the first detection region so as to surround the first detection region, and has an inner diameter substantially the same as the diameter φB of the second light flux at the time of the low numerical aperture. And an annular region having an outer diameter substantially the same as the diameter φA of the second light flux at the high numerical aperture. As a result, the outer light flux of the first light flux is incident on the second detection region 4a.

  The controller 50 includes a light emitting element driving circuit 51, a driving control circuit 52, and an opening switching circuit 53.

  The drive control circuit 52 outputs a control signal to the light emitting element drive circuit 51 while receiving the detection signal from the photodetector 4. The drive control circuit 52 includes two current-voltage conversion amplifiers 54a and 54b and an addition amplifier 55a, and is configured to be switchable between a first control state and a second control state. In the first control state, a control signal corresponding to the amount of received light of the first light beam received by the first detection region 4b is output. In the second control state, a control signal according to the amount of received light of the first light beam received by both detection regions 4b and 4a is output.

  The light emitting element driving circuit 51 is configured to output a feedback signal to the light emitting element 1a in accordance with the output voltage from the drive control circuit 52 and to control the amount of light emitted from the light emitting element 1a.

  The aperture switching circuit 53 controls switching of aperture limitation of the aperture limiting member 5 according to the base material thickness of the optical discs 7a and 7b to be loaded (distance from the surface of the optical disc on the objective lens 6 side to the recording layer). It is configured. This switching control is performed, for example, by controlling the voltage applied to the liquid crystal element.

  The operation of the optical disk drive configured as described above will be described below. When the optical disk 7a is loaded in the optical disk drive device, the controller 50 switches the aperture limiting member 5 to the second opening state where the numerical aperture is high, and switches the drive control circuit 52 to the second control state. .

  The light beam 10 emitted from the light emitting element 1 a is converted into substantially parallel light by the collimator lens 2 and is incident on the beam splitter 3. In the light beam 10 incident on the beam splitter 3, the second light beam, which is a part of the light beam 10, passes through the reflection surface 3 a of the beam splitter 3, while the remaining first light beam is reflected by the reflection surface 3 a of the beam splitter 3. The

  When passing through the aperture limiting member 5, the second light beam transmitted through the reflecting surface 3a becomes a light beam 10a whose aperture is limited to a light beam diameter φA. This light beam 10a passes through the objective lens 6 and is focused on the optical disk 7a. tie. The light beam 10 a reflected by the optical disk 7 a passes through the objective lens 6 and the aperture limiting member 5 and enters the beam splitter 3. This light beam 10a is reflected by the reflecting surface 3a, and a spot is formed on the photodetector 9 by the detection lens 8, whereby a servo signal and an RF signal are detected.

  On the other hand, the first light beam reflected by the reflecting surface 3 a of the beam splitter 3 enters the photodetector 4. This first light beam is branched from the light beam 10 at a high numerical aperture, and is incident on the entire surface of the first detection region 4b and the second detection region 4a. Therefore, the light detector 4 detects the light amount of the first light beam corresponding to the second light beam 10a having the diameter φA. The currents obtained in both detection regions 4b and 4a are converted into voltages by current-voltage conversion amplifiers 54a and 54b, respectively. Then, in the controller 50, the single signal C from the current-voltage conversion amplifier 54a connected to the first detection region 4b and the signals from both the current-voltage conversion amplifiers 54a and 54b are added by the addition amplifier 55a. The added signal D is obtained. When the numerical aperture is high, the addition signal D is output to the light emitting element driving circuit 51, and control for holding the output of the light emitting element 1a constant by the feedback signal from the light emitting element driving circuit 51 is performed. That is, when the numerical aperture is high, the amount of light from the light beam having the light beam diameter φA is received and control is performed accordingly.

  On the other hand, when the optical disk 7b is loaded in the optical disk drive device, the aperture limiting member 5 is switched to the first opening state where the numerical aperture is low, and the drive control circuit 52 is switched to the first control state. .

  The second light beam passing through the reflecting surface 3a of the beam splitter 3 and passing through the aperture limiting member 5 becomes a light beam 10b whose aperture is limited to the beam diameter φB, and is transmitted through the objective lens 6 and focused on the optical disc 7b in the same manner as described above. Tie. The light beam 10 b is incident on the objective lens 6, the aperture limiting member 5, and the beam splitter 3, is reflected by the reflecting surface 3 a, and forms a spot on the photodetector 9.

  On the other hand, the first light beam reflected by the reflecting surface 3 a of the beam splitter 3 is incident on the first detection region 4 b and the second detection region 4 a of the photodetector 4. Then, the controller 50 outputs the single signal C from the current-voltage conversion amplifier 54a connected to the first detection region 4b to the light emitting element driving circuit 51. That is, when the numerical aperture is low, the light amount of the first light beam 10b corresponding to the second light beam 10b having the light beam diameter φB is detected. Then, control for keeping the output of the light emitting element 1a constant is performed.

  According to such a configuration, it is possible to obtain a front light detection signal optimal for each numerical aperture (or an optical disc to be recorded or reproduced), and to obtain a numerical aperture (or an optical disc to be recorded or reproduced). In addition, the light emitting element 1a can be driven accurately.

  In the first embodiment, the first light beam and the second light beam that are branched by the beam splitter 3 and the first light beam that is incident on the photodetector 4 have the same diameter. The opening diameter of the opening restriction member 5 in the first opening state and the first detection area 4b are substantially the same diameter, and the opening diameter of the opening restriction member 5 in the second opening state and the outer diameter of the second detection area 4a. Are approximately the same diameter, and reliable total light quantity detection can be easily performed for each numerical aperture.

  In the first embodiment, since the switching between the first control state and the second control state is performed in conjunction with the opening restriction operation of the opening restriction member 5, the control of the controller 50 according to each numerical aperture. The state can be reliably matched, and the emitted light amount control by the light emitting element can be ensured.

  In the first embodiment, since the first detection region 4b and the second detection region 4a are formed concentrically, a detection region pattern corresponding to the inner light beam and the outer light beam of the first light beam is detected by the photodetector. A signal for controlling the amount of light corresponding to the numerical aperture can be obtained simply by configuring the number 4, and the apparatus configuration can be simplified.

(Embodiment 2)
FIG. 3 shows an optical disk drive apparatus according to Embodiment 2 of the present invention. As shown in FIG. 3, in the second embodiment, a light emitting element 1a used at a high numerical aperture and a light emitting element 1b used at a low numerical aperture are provided. In FIG. 3, the light beam 10 emitted from the light emitting element 1a is indicated by a broken line, and the light beam 11 emitted from the light emitting element 1b is indicated by a solid line.

  The light emitting element 1a and the light emitting element 1b emit light having different wavelengths. For example, the light emitting element 1a emits light having a wavelength of 405 nm, and the light emitting element 1b emits light having a wavelength of 650 nm. Exit. In the second embodiment, both the light emitting elements 1 a and 1 b are arranged in one package 1. Note that the light-emitting element 1a and the light-emitting element 1b are not limited to this, and the wavelength of light emitted from the light-emitting element 1a out of the wavelengths of 405 nm, 650 nm, and 790 nm is greater than the wavelength of light emitted from the light-emitting element 1b. Any combination that shortens the length is acceptable.

  The aperture limiting member 5 shields the outer peripheral portion of the second light beam 10 emitted from the light emitting element 1a and passes the light beam 10a having a diameter φA and guides it to the objective lens 6, while the second light beam emitted from the light emitting element 1b. The outer peripheral portion of the light beam 11 is shielded to pass the light beam 11a having a diameter φB and guided to the objective lens 6.

  When recording / reproducing the optical disk 7a at a high density, the controller 50 causes the light emitting element 1a to emit light, and restricts the light beam 10 emitted from the light emitting element 1a to be the aperture diameter φA by the aperture limiting member 5. It is configured. Further, when performing recording / reproduction of the optical disc 7b at a low density, the controller 50 causes the light emitting element 1b to emit light and restricts the aperture of the emitted light beam 11 from the light emitting element 1b to the light beam diameter φB by the aperture limiting member 5. It is configured to be applied. The light emitting element 1a and the light emitting element 1b are not driven at the same time, and only one of them is driven to emit light according to the optical discs 7a and 7b to be recorded or reproduced. Since other operations are the same as those in the first embodiment, detailed description thereof is omitted here.

  According to such a configuration, since the detection regions 4b and 4a are selected according to the wavelength of the first light beam received by the photodetector 4, light beams having different wavelengths are used for each numerical aperture. In this case, the light quantity detection according to each numerical aperture can be performed with high accuracy.

  The aperture limiting member 5 can also be configured by a wavelength selective filter that can adjust the diameter of the light beam based on the wavelength of the light beam that passes through it. In this case, the opening switching circuit 53 can be omitted.

  Other configurations are the same as those of the first embodiment.

(Embodiment 3)
FIG. 4 shows an optical disk drive apparatus according to Embodiment 3 of the present invention. As shown in FIG. 4, in the third embodiment, unlike the second embodiment, a plurality of light emitting elements are arranged in separate packages.

  In the third embodiment, the light emitting element 1 a is mounted on the package 1, while the light emitting element 12 a is mounted on the package 12. In FIG. 4, of the light beam 15 emitted from the light emitting element 1a, the light beam 15a whose outer peripheral portion is shielded by the aperture limiting member 5 to have a diameter φA is indicated by a broken line. Further, in the drawing, among the light flux 16 emitted from the light emitting element 12a, the light flux 16a whose outer peripheral portion is shielded by the aperture limiting member 5 to have a diameter φB is indicated by a solid line.

  The light emitting element 1a and the light emitting element 12a emit light having different wavelengths. For example, the light emitting element 1a emits light having a wavelength of 405 nm, and the light emitting element 12a emits light having a wavelength of 650 nm. . The light emitting element 1a is driven when the numerical aperture is high, and the light emitting element 12a is driven when the numerical aperture is low. The light emitting element 1a and the light emitting element 12a are not driven at the same time, and only one of them is driven according to the optical disk to be recorded or reproduced. Note that the light emitting element 1a and the light emitting element 12a are not limited to this, and the wavelength of the emitted light from the light emitting element 1a out of the wavelengths of 405 nm, 650 nm, and 790 nm is larger than the wavelength of the emitted light from the light emitting element 12a. Any combination that shortens the length is acceptable.

  A collimating lens 13 is also disposed between the light emitting element 12 a and the beam splitter 3. The collimating lens 2 converts the light beam 15 emitted from the light emitting element 1a and directed to the beam splitter 3 into a parallel light beam. On the other hand, the collimating lens 13 converts the light beam 16 emitted from the light emitting element 12a and directed to the beam splitter 3 into a parallel light beam.

  The light beam 15 from the light emitting element 1a and the light beam 16 from the light emitting element 12a are incident on the beam splitter 3 from directions orthogonal to each other. The reflecting surface 3a of the beam splitter 3 splits the light beam emitted from the light emitting element 1a into a first light beam and a second light beam. The first light flux is reflected by the reflecting surface 3a and bent 90 degrees to be guided to the photodetector 4. The second light beam is transmitted through the reflecting surface 3 a and guided to the objective lens 6. The reflecting surface 3a of the beam splitter 3 branches the light beam emitted from the light emitting element 12a into a first light beam and a second light beam. The first light flux is transmitted through the reflecting surface 3 a and guided to the photodetector 4. The second light flux is reflected by the reflecting surface 3a and bent 90 degrees to be guided to the objective lens 6.

  A beam splitter 14 is disposed between the beam splitter 3 and the aperture limiting member 5. The beam splitter 14 is for branching the light beam and has a reflecting surface 14a. The reflection surface 14 a is configured to transmit the light beam from the beam splitter 3 and guide it to the objective lens 6, while reflecting the light beam transmitted through the objective lens 6 and guide it to the photodetector 9.

  The aperture limiting member 5 is disposed between the beam splitter 14 and the objective lens 6.

  At a high numerical aperture for recording / reproducing the optical disk 7a at a high density, the light emitting element 1a emits light, and the aperture limiting member 5 applies aperture limitation so that the emitted light beam 15 from the light emitting element 1a is a light beam diameter φA. On the other hand, at a low numerical aperture for recording / reproducing the optical disc 7b at a low density, the light emitting element 12a emits light, and an aperture restriction is applied such that the outgoing light beam 16 from the light emitting element 12a has a light beam diameter φB.

  A light beam 15 emitted from the light emitting element 1a at a high numerical aperture is converted into substantially parallel light by the collimator lens 2, is incident on the beam splitter 3, and is branched into a first light beam and a second light beam. The second light beam passes through the reflecting surface 3a and enters the beam splitter 14, passes through the reflecting surface 14a, and is restricted by the opening restricting member 5 to the diameter φA. This light beam 15a enters the objective lens 6 and focuses on the optical disk 7a. Then, the light beam 15a reflected by the optical disc 7a is incident on the beam splitter 14 through the objective lens 6 and the aperture limiting member 5, reflected by the reflecting surface 14a, and condensed on the photodetector 9 by the detection lens 8. Is done. Thus, the servo signal and the RF signal are detected.

  On the other hand, the light beam 16 emitted from the light emitting element 12a at the time of the low numerical aperture is converted into substantially parallel light by the collimating lens 13, enters the beam splitter 3, and is branched into the first light beam and the second light beam. The second light beam is reflected by the reflecting surface 3a, is incident on the beam splitter 14, passes through the reflecting surface, and is aperture-limited by the aperture limiting member 5 to the diameter φB. This light beam 16a enters the objective lens 6 and focuses on the optical disk 7b. The light beam 16a reflected by the optical disk 7b passes through the objective lens 6 and the aperture limiting member 5 again, enters the beam splitter 14, is reflected by the reflecting surface 14a, and is collected on the photodetector 9 by the detection lens 8. The Thus, the servo signal and the RF signal are detected.

  The first light beam branched by the reflecting surface 3 a of the beam splitter 3 is incident on the photodetector 4 at both high numerical aperture and low numerical aperture. At this time, the emitted light beam from the light emitting element 1a is detected in the first detection region 4b and the second detection region 4a. The detection signals from the detection regions 4b and 4a are converted into voltages by the current-voltage conversion amplifiers 54a and 54b, respectively, and the single signal C and the addition signal D by the addition amplifier 55a are obtained.

  When the numerical aperture is high, the addition signal D is used as a feedback signal from the controller 50 to perform control to keep the output of the light emitting element 1a constant. That is, when the numerical aperture is high, light amount control is performed based on the total received light amount of the received light amount of the outer light beam and the received light amount of the inner light beam. On the other hand, when the numerical aperture is low, the single signal C is used as a feedback signal from the controller 50 to perform control to keep the output of the light emitting element 12a constant. That is, when the numerical aperture is low, light amount control based on the amount of light received by the inner luminous flux is performed.

  According to such a configuration, even if the light beam diameter of a light beam having a short wavelength emitted from the light emitting element 1a is increased, the total light amount of the light beam can be detected by the photodetector 4, and a plurality of numerical apertures can be obtained. Even if it is set, high-precision light amount control can be performed.

  The aperture limiting member 5 can also be configured by a wavelength selection type filter that can adjust the diameter of the light beam based on the wavelength of the light beam that passes therethrough. In this way, the configuration of the opening limiting member 5 can be simplified. In this case, the opening switching circuit 53 can be omitted.

  Other configurations are the same as those of the second embodiment.

(Embodiment 4)
FIG. 5 shows an optical disk drive apparatus according to Embodiment 4 of the present invention, and FIG. 6 shows a photodetector and a drive control circuit 52 provided in the optical disk drive apparatus.

  As shown in FIG. 5, a hologram element 17 is arranged between the beam splitter 3 and the photodetector (first detector) 18. This hologram element 17 separates the front light according to the numerical aperture. The photodetector 18 detects the front light separated by the hologram element 17.

  As shown in FIG. 7, the hologram element 17 includes a first diffractive part 17b and a second diffractive part 17a. Both diffractive portions 17b and 17a are formed substantially concentrically, and the first diffractive portion 17b is constituted by a circular diffractive region having a diameter of approximately φB, while the second diffractive portion 17a is the first diffractive portion 17a. It is constituted by an annular diffraction region having an outer diameter of approximately φA formed around the diffraction part 17b. The outer diameter of the first diffractive portion 17b is substantially the same as the beam diameter φB of the second light beam when the aperture is restricted by the aperture restricting member 5 when the numerical aperture is low. The outer diameter of the second diffractive portion 17a is substantially the same as the beam diameter φA of the second light beam emitted from the light emitting element 1a when the aperture is limited by the aperture limiting member 5 when the numerical aperture is high.

  As shown in FIG. 6, the photodetector 18 is provided with a first detection region 18b and a second detection region 18a. The front light diffracted by the first diffraction unit 17b is incident on the first detection region 18b, and the light spot 18d is formed in the first detection region 18b. On the other hand, the front light diffracted by the second diffraction unit 17a is incident on the second detection region 18a, and the light spot 18c is formed in the second detection region 18a.

  The first detection area 18b is formed in a larger area than the light spot 18d. That is, since the oscillation wavelengths of the light emitted from the light emitting elements 1a and 12a are different, the diffraction directions diffracted by the diffraction region 17b are different, but the first detection region 18b can receive both of these light beams. It has a size.

  In the fourth embodiment, the first light flux (reflected by the reflecting surface 3a) out of the light flux 15 emitted from the light emitting element 1a, converted into a parallel light flux by the collimator lens 2 and incident on the beam splitter 3 at a high numerical aperture. Pre-light) enters the hologram element 17. At this high numerical aperture, the inner light beam is diffracted by the first diffractive portion 17b of the hologram element 17, and the outer light beam is diffracted by the second diffractive portion 17a. At this time, the inner luminous flux and the outer luminous flux are diffracted in different directions, and the inner luminous flux is collected in the first detection area 18b of the photodetector 18, and the outer luminous flux is collected in the second detection area 18a as light spots 18d and 18c, respectively. To be lighted.

  On the other hand, when the numerical aperture is low, out of the light beam 16 emitted from the light emitting element 12a, converted into a parallel light beam by the collimator lens 13 and incident on the beam splitter 3, the first light beam (front light) transmitted through the reflecting surface 3a is a hologram element. 17 is incident. The inner light flux of the light flux 16 is diffracted by the first diffraction portion 17 b of the hologram element 17 and detected by the first detection region 18 b of the photodetector 18. The outer light flux of the light flux 16 is diffracted by the second diffracting portion 17a and detected by the second detection region 18a.

  The currents generated in the detection regions 18b and 18a are converted into voltages by the current-voltage conversion amplifiers 54a and 54b, respectively, and the single signal E and the addition signal F passing through the addition amplifier 55a are obtained. When the numerical aperture is high, the addition signal F is used as a feedback signal, and the light amount control of the light emitting element 1a is executed. On the other hand, when the numerical aperture is low, the single signal E is used as a feedback signal, and the light amount control of the light emitting element 12a is executed. The servo signal and RF signal detection operations are the same as those in the third embodiment.

  According to the fourth embodiment, the inner light beam and the outer light beam of the first light beam branched by the beam splitter 3 are separately diffracted by the diffraction units 17b and 17a of the hologram element 17 to divide both light beams. Therefore, the degree of freedom of the detection area pattern of the photodetector 18 can be increased.

  In the fourth embodiment, the patterns of the diffracting portions 17a and 17b are formed so that the light beams diffracted by the diffracting portions 17a and 17b are condensed on the detection regions 18a and 18b. The detector 18 can be made smaller.

  The aperture limiting member 5 can also be configured by a wavelength selective filter that can adjust the diameter of the light beam based on the wavelength of the light beam that passes through it. In this case, the opening switching circuit 53 can be omitted.

  Other configurations are the same as those of the third embodiment.

(Embodiment 5)
FIG. 8 shows an optical disk drive apparatus according to Embodiment 5 of the present invention. As shown in FIG. 8, in the fifth embodiment, a condenser lens 19 is disposed between the hologram element 17 and the photodetector 18. The condenser lens 19 condenses the light beam emitted from the beam splitter 3 on the photodetector 18.

  In the fifth embodiment, the first light beam (front light) reflected by the reflecting surface 3a out of the light beam 15 emitted from the light emitting element 1a and incident on the beam splitter 3 through the collimating lens 2 at a high numerical aperture. Is incident on the hologram element 17. The first light beam diffracted by the diffraction region 17a and the diffraction region 17b of the hologram element 17 is condensed by the condenser lens 19 on the detection regions 18a and 18b of the photodetector 18 as light spots 18c and 18d, respectively.

  On the other hand, when the numerical aperture is low, out of the light beam 16 emitted from the light emitting element 12a and incident on the beam splitter 3 through the collimator lens 13, the first light beam transmitted through the reflecting surface 3a is incident on the hologram element 17. At this low numerical aperture, the light is diffracted by the hologram element 17 and condensed on the detection areas 18a and 18b of the photodetector 18 through the condenser lens 9.

  The currents generated in the detection regions 18b and 18a are converted into voltages by the current-voltage conversion amplifiers 54a and 54b, respectively, and the single signal E and the addition signal F passing through the addition amplifier 55a are obtained. The addition signal F is used as a feedback signal when the numerical aperture is high, and the single signal E is used as a feedback signal when the numerical aperture is low, and output control of the light emitting elements 1a and 12a is performed. The servo signal and RF signal detection operations are the same as those in the fourth embodiment.

  According to the fifth embodiment, it is possible to obtain a signal for controlling the amount of light by condensing the first light flux on the photodetector 18 by the condenser lens 19.

  The aperture limiting member 5 can also be configured by a wavelength selective filter that can adjust the diameter of the light beam based on the wavelength of the light beam that passes through it. In this case, the opening switching circuit 53 can be omitted.

  Other configurations are the same as those of the fourth embodiment.

(Embodiment 6)
FIG. 9 shows an optical disk drive apparatus according to Embodiment 6 of the present invention, and FIG. 10 shows a diffraction region provided in the hologram element 21.

  As shown in FIG. 9, the light emitting element 20 a is disposed in the integrated unit 20. The sixth embodiment has one light emitting element 20a as in the first embodiment. In the integrated unit 20, a photodetector 20b is disposed. The photodetector 20b is a photodetector for detecting front light, RF signal, and servo signal.

  A hologram element 21 is attached to the integrated unit 20. The hologram element 21 is disposed between the light emitting element 20a and the collimating lens 2. A diffraction region 21b for servo signal detection and RF signal detection is formed on the upper surface of the hologram element 21, and a reflective diffraction region for detecting front light is formed on the lower surface (incident surface of incident light from the light emitting element 20a). 21a is formed. The outer diameter φA ′ of the diffraction region 21a corresponds to the light beam diameter φA when the aperture is restricted when the numerical aperture is high, and the outer diameter φB ′ of the diffraction region 21b is that when the aperture is restricted when the numerical aperture is low. This corresponds to the beam diameter φB.

  In the sixth embodiment, a part of the light beam 10 emitted from the light emitting element 20a is diffracted and reflected by the diffraction region 21a and the diffraction region 21b, and the first detection region and the second detection region (see FIG. (Not shown). The currents output from both detection areas are converted into voltages by the current-voltage conversion amplifiers 54a and 54b, respectively, and a signal is obtained by the addition amplifier 55a. Further, these signals are selected depending on whether the numerical aperture is high or low, and the drive control of the light emitting element 20a is performed to control the output of the light emitting element 20a to be constant.

  On the other hand, the 0th-order light transmitted through the hologram element 21 is converted into substantially parallel light by the collimator lens 2 and is restricted by the aperture restricting member 5 to the light beam diameter φA when the numerical aperture is high. The opening is limited. This light beam is incident on the objective lens 6 and focuses on the optical disc 7a when the numerical aperture is high, and on the optical disc 7b when the numerical aperture is low. The light beam reflected by the optical discs 7 a and 7 b passes through the objective lens 6 and the aperture limiting member 5 again, enters the collimator lens 2, is condensed, and enters the hologram element 21. This light beam is diffracted by the diffraction region 21b on the surface of the hologram element 21, and is focused on the light detection unit on the light detector 20b to obtain a servo signal and an RF signal.

  Other configurations are the same as those in the first embodiment.

(Embodiment 7)
FIG. 11 shows an optical disk drive apparatus according to Embodiment 7 of the present invention. As shown in FIG. 11, in the seventh embodiment, the light emitting element 22a housed in the package 22 is configured to emit light having two different wavelengths. The light emitting element 22a has a configuration in which two chips that emit light of different wavelengths are provided. However, since these chips are arranged close to each other, they are drawn from the same position in FIG. 11 for convenience. ing.

  The light emitting element 1a emits a light beam 15 having a wavelength of 405 nm, and the light emitting element 22a is configured to emit a light beam 24 having a wavelength of 790 nm and a light beam 23 having a wavelength of 650 nm. Note that the light emitting element 1a and the light emitting element 22a are not driven simultaneously, and only one of them is driven to emit light. The light emitting element 22a does not emit the light beam 24 having a wavelength of 790 nm and the light beam 23 having a wavelength of 650 nm at the same time, and emits either one of them.

  The aperture limiting member 26 limits the aperture of the light beam that passes therethrough. The aperture limiting member 26 is configured so that the aperture can be limited to three types of diameters φA, φB, and φC. The opening limiting member 26 is configured to switch the opening state by applying a voltage to the liquid crystal element, for example.

  The light beams 23 and 24 emitted from the light emitting element 22a are transmitted through the reflection surface 3a of the beam splitter 3 and are incident on a photodetector 25 as a first detector. As shown in FIG. 12, the photodetector 25 is formed with three detection regions arranged concentrically with each other. A second detection region 25b is formed around the first detection region 25c, and a third detection region 25a is formed around the second detection region 25b. The first detection region 25c is configured by a circular region having substantially the same diameter as φC, which is a small diameter light beam diameter. The second detection region 25b is configured by an annular region having an inner diameter of φC and an outer diameter of φB, which is a medium beam diameter. The third detection region 25a is configured by an annular region having an inner diameter of φB and an outer diameter of φA that is a large luminous flux diameter. The first detection area 25c receives the inner luminous flux, the third detection area 25a receives the outermost luminous flux, and the second detection area 25b receives the outer luminous flux between the inner luminous flux and the outermost luminous flux.

  The aperture switching circuit 53 of the controller 50 identifies the optical disc by causing the light emitting elements 1a and 22a to emit light at each wavelength and detecting the reflectivity, signal type, amplitude, frequency, etc. of the optical disc loaded at that time. Based on this, the opening restriction member 26 switches the opening restriction, and the light emitting elements 1a and 22a to be used are selected.

  The drive control circuit 52 includes three current-voltage conversion amplifiers 54a, 54b, and 54c and two addition amplifiers 55a and 55b, and is configured to be switchable between a first control state, a second control state, and a third control state. ing. In the first control state, a control signal corresponding to the amount of light received by the first detection region 25c is output. In the second control state, a control signal corresponding to the added light reception amount between the light reception amount of the first detection region 25c and the light reception amount of the second detection region 25b is output. In the third control state, a control signal corresponding to the total received light amount obtained by adding the received light amount of the first detection region 25c, the received light amount of the second detection region 25b, and the received light amount of the third detection region 25a is output.

  In the seventh embodiment, when the aperture is limited to φA, that is, when the numerical aperture is high, the drive control circuit 52 of the controller 50 is in the third control state. At this high numerical aperture, light is emitted from the light emitting element 1a. The light emitted from the light emitting element 1a and reflected by the reflection surface 3a of the beam splitter 3 is detected by the photodetector 25, and the light transmitted through the reflection surface 3a is detected by the photodetector 9 as in the third embodiment. Detected.

  In the photodetector 25, the light emitted from the light emitting element 1a is received in all of the first detection region 25c, the second detection region 25b, and the third detection region 25a. The output signals from the detection regions 25c, 25b, and 25a are input to the addition amplifiers 55a and 55b through the current-voltage conversion amplifiers 54a, 54b, and 54c, respectively, and the addition signal E of all the detection regions 25c, 25b, and 25a. In response to the addition signal E, the output of the light emitting element 1a is controlled to be kept constant.

  On the other hand, when the aperture is limited to φB, that is, when the numerical aperture is medium, the drive control circuit 52 of the controller 50 is in the second control state. At the middle numerical aperture, light is emitted from the light emitting element 22a. This light is the light having the second shortest wavelength among the three types of wavelengths, and is the light having the shorter wavelength emitted from the light emitting element 22a. The light emitted from the light emitting element 22a and transmitted through the reflecting surface 3a of the beam splitter 3 is detected by the photodetector 25, and the light reflected by the reflecting surface 3a is detected by the photodetector 9 as in the third embodiment. The

  In the photodetector 25, the output signals from the detection regions 25c and 25b are input to the addition amplifier 55a via the current-voltage conversion amplifiers 54a and 54b and output as the addition signal D. Then, in accordance with the addition signal D, control for keeping the output of the light emitting element 22a constant is performed.

  When the aperture of the light beam is limited to φC, that is, when the numerical aperture is low, the drive control circuit 52 of the controller 50 is in the first control state. At this low numerical aperture, light is emitted from the light emitting element 22a. This light is light having a longer wavelength emitted from the light emitting element 22a. The light emitted from the light emitting element 22a and transmitted through the reflecting surface 3a of the beam splitter 3 is detected by the photodetector 25, and the light reflected by the reflecting surface 3a is detected by the photodetector 9 as in the third embodiment. The

  In the photodetector 25, the output signal from the first detection region 25c is output as a single signal C through the current-voltage conversion amplifier 54a. Then, in accordance with the single signal C, control is performed to keep the output of the light emitting element 22a constant.

  Other configurations are the same as those in the third embodiment.

(Embodiment 8)
FIG. 13 shows an optical disk drive apparatus according to the eighth embodiment of the present invention. As shown in FIG. 13, in the eighth embodiment, three light emitting elements 1a, 22a, and 28a are provided in separate packages 1, 22, and 28, respectively. The wavelength of the light beam 15 emitted from the light emitting element 1a is 405 nm, the wavelength of the light beam 23 emitted from the light emitting element 22a is 790 nm, and the wavelength of the light beam 27 emitted from the light emitting element 28a is 650 nm. These light emitting elements 1a, 22a, and 28a are not driven simultaneously, and any one is selected and driven.

  A beam splitter 30 is disposed between the collimating lens 2 and the beam splitter 3. A collimating lens 32 is disposed between the beam splitter 30 and the light emitting element 28a. The collimating lens 32 converts the light beam 27 emitted from the light emitting element 28a and directed to the beam splitter 30 into a parallel light beam.

  The beam splitter 30 includes a reflecting surface 30a that transmits the emitted light beam 15 from the light emitting element 1a and reflects the emitted light beam 27 from the light emitting element 28a at a reflection angle of 45 degrees.

  In the eighth embodiment, the light beam 15 is emitted from the light emitting element 1a at a high numerical aperture. The light beam 15 passes through the collimating lens 2 and the reflection surface 30 a of the beam splitter 30, and then is branched by the reflection surface 3 a of the beam splitter 3.

  At the middle numerical aperture, the light beam 27 is emitted from the light emitting element 28a. The light beam 27 passes through the collimator lens 32, is reflected by the reflecting surface 30 a of the beam splitter 3, and enters the beam splitter 3. And this light beam 27 is branched by the reflecting surface 3a.

  When the numerical aperture is low, the light beam 23 is emitted from the light emitting element 22a. This light beam 23 passes through the collimating lens 13 and enters the beam splitter 3. And this light beam 23 is branched by the reflective surface 3a.

  The path of the light beams 15, 27, and 23 branched by the beam splitter 3 is the same as in the seventh embodiment at any time when the numerical aperture is high, when the numerical aperture is low, and when the numerical aperture is low. Other configurations are the same as those of the seventh embodiment.

(Embodiment 9)
FIG. 14 shows an optical disk drive apparatus according to Embodiment 9 of the present invention. As shown in FIG. 14, in the ninth embodiment, an aperture limiting member 34 is disposed between the beam splitter 3 and the photodetector 4.

  The aperture limiting member 34 is used to limit the aperture of the first light beam branched by the beam splitter 3. The aperture limiting member 34 is a wavelength selection unit that can adjust the beam diameter based on the wavelength of the passing light beam. It is composed of mold filters. That is, when the outgoing light beam 10 from the light emitting element 1a passes, the aperture limiting member 34 shields the outer peripheral portion and allows the light beam having a diameter φA to pass (second opening state), while the outgoing light beam from the light emitting element 1b. When 11 passes, it is configured to shield the outer peripheral portion thereof and allow the light flux having a diameter φB to pass (first opening state).

  Note that the aperture limiting member 34 is not limited to the one configured by the wavelength selection type filter. For example, the aperture limiting member 34 may be configured to switch the first aperture state and the second aperture state by controlling the voltage applied to the liquid crystal element. Can be switched between the first opening state and the second opening state, such as a configuration in which the opening state is switched by a light shielding member having an opening with a variable inner diameter, or a configuration in which a light shielding member having a plurality of openings having different inner diameters is taken in and out. It is good also as a simple structure. Other configurations are the same as those of the second embodiment.

It is the schematic which shows the structure of the optical disk drive device based on Embodiment 1 of this invention. It is a figure which shows the photodetector and drive control circuit which were provided in the said optical disk drive device. It is the schematic which shows the structure of the optical disk drive device based on Embodiment 2 of this invention. It is the schematic which shows the structure of the optical disk drive device based on Embodiment 3 of this invention. It is the schematic which shows the structure of the optical disk drive device based on Embodiment 4 of this invention. It is a figure which shows the photodetector and drive control circuit which were provided in the said optical disk drive device. It is the schematic which shows the structure of the hologram element provided in the said optical disk drive device. It is the schematic which shows the structure of the optical disk drive device based on Embodiment 5 of this invention. It is the schematic which shows the structure of the optical disk drive device based on Embodiment 6 of this invention. It is the schematic which shows the diffraction area on the hologram element provided in the said optical disk drive device. It is the schematic which shows the structure of the optical disk drive device based on Embodiment 7 of this invention. It is a figure which shows the photodetector and drive control circuit which were provided in the said optical disk drive device. It is the schematic which shows the structure of the optical disk drive device based on Embodiment 8 of this invention. It is the schematic which shows the structure of the optical disk drive device based on Embodiment 9 of this invention. It is the schematic which shows the structure of the conventional optical disk drive device. It is a conceptual diagram which shows roughly the detector in the conventional optical disk drive device, and the waveform of the light beam which injects into this.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Package 1a Light emitting element 2 Collimating lens 3 Beam splitter 4 Optical detector 5 Aperture limiting member 6 Objective lens 7a, 7b Optical disk 9 Optical detector 10 Light beam 11 Light beam 12 Package 12a Light emitting element 13 Collimating lens 14 Beam splitter 15 Light beam 16 Light beam 17 Light beam 17 Hologram element 18 Photo detector 19 Condensing lens 21 Hologram element 22 Package 22a Light emitting element 28 Package 28a Light emitting element 34 Aperture limiting member 50 Controller 51 Light emitting element drive circuit 52 Drive control circuit 53 Aperture switching circuit

Claims (16)

An optical disk drive capable of operating at a numerical aperture corresponding to each of a plurality of optical disks,
A light source, a branch element that branches the light beam emitted from the light source into a first light beam and a second light beam, a first detector that receives the first light beam branched by the branch element, and the first detection A controller that controls the amount of light emitted from the light source in accordance with the amount of light received by the light source; and a second detector that receives light after the second light flux is reflected by an optical disk,
The first detector includes a first detection region that receives an inner light beam of the first light beam, and at least one second detection region that receives an outer light beam of the first light beam,
The controller is configured to control a light emission amount of the light source based on a light reception amount of the first detection region, and a light source amount of the light source based on the light reception amounts of the first detection region and the second detection region. An optical disc driving apparatus configured to be switchable to a second control state for controlling an emission amount. Between the branch element and the optical disc, an aperture limiting member that allows the second light beam branched by the branch element to pass is disposed,
The opening limiting member is switchable between at least a first opening state and a second opening state that allows the second light flux having a diameter larger than that of the first opening state to pass therethrough. 2. An optical disk drive device according to 1. Between the light source and the branch element is provided a collimating lens that converts a light beam from the light source toward the branch element into a parallel light beam,
The first detection region is formed in a circular shape having substantially the same diameter as the second light flux passing through the aperture limiting member in the first opening state,
The second detection region is formed in an annular shape that is provided around the first detection region and has an outer diameter substantially the same as the second light flux that passes through the aperture limiting member in the second opening state. The optical disk drive device according to claim 2, wherein The aperture limiting member is configured to perform an aperture limiting operation to adjust a beam diameter of the second light beam;
4. The controller according to claim 3, wherein the controller is configured to switch between the first control state and the second control state in conjunction with an opening restriction operation of the opening restriction member. Optical disk drive device. As the light source, a plurality of light sources that emit light having different wavelengths are provided,
Between the branch element and the optical disc, an aperture limiting member that allows the second light beam branched by the branch element to pass is disposed,
The aperture limiting member is configured by a filter that adjusts the diameter of the second light flux passing therethrough based on the wavelength of the second light flux,
2. The optical disk drive device according to claim 1, wherein the controller is configured to switch a control state depending on which of the light sources emits light. As the light source, a plurality of light sources that emit light having different wavelengths are provided,
The optical disk drive device according to claim 1, wherein the controller is configured to switch a control state depending on which of the light sources emits light. As the light source, a first light source and a second light source that emits light having a wavelength shorter than that of the first light source are provided,
The first detection region is configured to receive the first light flux emitted from the first light source and branched by the branch element;
The optical disc driving apparatus according to claim 6, wherein the second detection region is configured to receive the first light flux emitted from the second light source and branched by the branch element. 8. The optical disk drive according to claim 7, wherein the numerical aperture is set to any two of about 0.45, about 0.6, and about 0.85. As the light source, a first light source, a second light source that emits light having a shorter wavelength than the first light source, and a third light source that emits light having a shorter wavelength than the second light source are provided.
The first detector receives a first detection region that receives an inner light beam of the first light beam, a second detection region that receives an outer light beam of the first light beam, and an outermost light beam of the first light beam. A third detection region,
The controller is configured to control a light emission amount of the first light source based on a light reception amount of the first detection region, and based on the light reception amounts of the first detection region and the second detection region. A third control state that controls the amount of light emitted from the third light source based on a second control state that controls the amount of light emitted from the second light source and the total amount of light received in the first detection region, the second detection region, and the third detection region. The optical disk drive device according to claim 6, wherein the optical disk drive device is configured to be switchable to a control state. 10. The optical disk drive device according to claim 9, wherein the numerical aperture is set to about 0.45, about 0.6, and about 0.85. The optical disc driving apparatus according to claim 6, wherein the plurality of light sources are provided in separate packages. The optical disk drive device according to any one of claims 1 to 11, wherein the first detection area and the second detection area are formed concentrically. A diffractive element is disposed between the branch element and the first detector;
The diffraction element includes a first diffractive portion that diffracts the inner light beam toward a first detection region, and a second diffractive portion that diffracts the outer light beam toward a second detection region. The optical disk drive apparatus according to claim 1, wherein 14. The optical disk drive device according to claim 13, wherein a condensing element is disposed between the diffraction element and the first detector. Between the branch element and the first detector, an aperture limiting member that allows the first light beam branched by the branch element to pass is disposed,
The aperture limiting member is switchable between at least a first aperture state and a second aperture state that allows a second beam having a diameter larger than that of the first aperture state to pass a beam having substantially the same diameter. The optical disk drive device according to any one of claims 1, 2, 6 to 12. 16. The optical disk drive device according to claim 1, wherein the branch element is configured by a hologram element.

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