JP2004152355A - Optical pickup device and optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device, by which the information regarding a light emitting power of a light source can be outputted with satisfied responsiveness without increases in the size and the cost of the device. <P>SOLUTION: A part of luminous flux outgoing from the light source 51a is diffracted by a polarizing hologram 58 and received by an outgoing light quantity detector 57. Then, by setting the diffraction efficiency of the polarizing hologram to be high for the outgoing luminous flux and low for the return luminous flux, the information regarding the light emitting power of the light source can be outputted with the satisfied responsiveness without reducing the light quantity of the return luminous flux which is received by a return light detector 51b, even though the polarizing hologram is arranged on a common optical path for back and forth. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical pickup device and an optical disk device, and more particularly, to an optical pickup device that irradiates a recording surface of an information recording medium with light and receives light reflected from the recording surface, and an optical disk including the optical pickup device. Equipment related.
[0002]
[Prior art]
2. Description of the Related Art In recent years, personal computers have been able to handle AV (Audio-Visual) information such as music and video as their functions have improved. Since the information amount of these AV information is very large, optical discs such as CD (compact disc) and DVD (digital versatile disc) have been attracting attention as information recording media. Optical disk devices have become widespread as one of peripheral devices for personal computers. In an optical disk device, recording or erasing of information is performed by irradiating a minute spot of a laser beam (laser beam) on a recording surface of an optical disk on which a spiral or concentric track is formed, and based on reflected light from the recording surface. To reproduce information. Therefore, an optical pickup device is mounted on an optical disc device as a device for irradiating a recording surface of an information recording medium with laser light and receiving reflected light from the recording surface.
[0003]
This optical pickup device generally includes a light source that emits laser light at a predetermined emission power (output), guides the laser light emitted from the light source to the recording surface of the optical disk, and reflects the laser light reflected by the recording surface. And a detection system including a light receiving element disposed at the light receiving position. The detection system outputs not only reproduction information of data recorded on the recording surface but also a signal including information necessary for controlling the position of the optical pickup device itself and the objective lens.
[0004]
In an optical disk, information is recorded by the length of each of a mark (pit) area and a space area having different reflectances and a combination thereof. Therefore, when information is recorded on the optical disk, the light emission power of the light source is controlled so that a mark area and a space area having a predetermined length are formed at predetermined positions.
[0005]
For example, in a write-once optical disc (hereinafter, referred to as a “dye-type disc” for convenience) such as a CD-R (CD-recordable), a DVD-R (DVD-recordable), and a DVD + R (DVD + recordable) including an organic dye in a recording layer. When forming the mark area, the light emission power is increased to heat and dissolve the dye, and the substrate portion in contact therewith is altered and deformed. On the other hand, when the space region is formed, the light emission power is set to be as low as during reproduction so that the substrate does not deteriorate or deform. As a result, the reflectance in the mark area is lower than that in the space area.
[0006]
In addition, rewritable optical disks such as a CD-RW (CD-rewritable), a DVD-RW (DVD-rewritable), and a DVD + RW (DVD + rewritable) including a special alloy in a recording layer (hereinafter also referred to as a “phase-change disk” for convenience) In (2), when forming the mark area, the special alloy is heated to a first temperature by a laser beam, the emission power is reduced to rapidly cool the special alloy, and the special alloy is in an amorphous state. . When forming the space region, the special alloy is heated to a second temperature (<first temperature) by a laser beam, and then the special alloy is gradually cooled to bring the special alloy into a crystalline state. Thereby, the reflectance is lower in the mark area than in the space area.
[0007]
Usually, a light source such as a semiconductor laser is a current drive type, and its light emission power is controlled by a current (drive current) supplied from a driver. However, even when the driving current supplied to the light source is kept constant, the light emission power may fluctuate due to temperature fluctuation or humidity fluctuation in the light source and in the vicinity of the light source, which may lead to deterioration of recording quality. Therefore, the present applicant has previously proposed an optical pickup device that monitors the light amount of a light beam emitted from a light source and performs feedback control of the emission power based on the monitor information (see Patent Documents 1 and 2). This makes it possible to stably perform recording with excellent recording quality.
[0008]
[Patent Document 1]
JP-A-9-63101
[Patent Document 2]
JP 2001-256666 A
[0009]
[Problems to be solved by the invention]
However, thereafter, the recording speed has been increased, and the optical pickup devices disclosed in Patent Document 1 and Patent Document 2 have been insufficient in responsiveness at high speed. Also, in terms of cost, it has become difficult to respond to the recent demand for lower prices.
[0010]
The present invention has been made under such circumstances, and a first object of the present invention is to provide an optical pickup device capable of outputting information regarding the light emission power of a light source with good responsiveness without increasing the size and cost. Is to provide.
[0011]
It is a second object of the present invention to provide an optical disk device capable of accurately and stably accessing an information recording medium at a high speed.
[0012]
[Means for Solving the Problems]
The invention according to claim 1 is an optical pickup device that irradiates a recording surface of an information recording medium with light and receives reflected light from the recording surface, the light source comprising: a light source; An objective lens for condensing light on a recording surface, and a polarization hologram disposed on an optical path of a light beam emitted from the light source toward the objective lens and diffracting a part of the light beam in a predetermined direction, reflected on the recording surface An optical pickup device comprising: an optical system for guiding the returned return light beam to a predetermined light receiving position; a return light detector disposed at the light receiving position; and an emission light amount detector for receiving the light beam diffracted by the polarization hologram. It is.
[0013]
The polarization hologram in the present specification is not only a member having predetermined irregularities formed so that the diffraction efficiency is different depending on the polarization state of the incident light beam, but also includes a member such as a glass substrate for holding the member. Also included are elements and components that are part of the structure, and those in which irregularities of a predetermined depth are formed on part of the surface of glass or the like. The shape of the polarization hologram is not limited as long as it can diffract a part of the light beam emitted from the light source in a predetermined direction.
[0014]
According to this, a light beam emitted from the light source (hereinafter simply referred to as “emitted light beam”) is condensed on the recording surface of the information recording medium via the objective lens, and the return light beam reflected on the recording surface is returned. The light is received by the photodetector. Further, a part of the emitted light beam is diffracted by the polarization hologram, and is received by the emitted light amount detector. Here, since the polarization hologram has a different diffraction efficiency depending on the polarization state of the incident light, for example, the diffraction efficiency is high in the polarization direction of the output light beam, and the diffraction efficiency is high in the polarization direction of the return light beam. By setting to be lower, even if the polarization hologram is arranged on the common optical path of the forward path and the return path, the light amount of the return light beam received by the return light detector does not decrease. That is, the signal level and the S / N ratio of the output signal of the return light detector are not reduced. Furthermore, since a small-sized and inexpensive general-purpose product can be used as the polarization hologram and the emitted light amount detector, it is possible to output information regarding the light emission power of the light source with good responsiveness without increasing the size and cost. It becomes possible.
[0015]
In this case, as in the optical pickup device according to claim 2, the polarization hologram has an incident angle of the light beam with respect to the polarization hologram, and an incident angle when the intensity of the diffracted light of a specific order is selectively increased. It can be assumed that they are set to substantially match. In such a case, most of the diffracted light diffracted by the polarization hologram can be received by the output light amount detector, so that the amount of light condensed on the recording surface does not decrease and the output light amount detector The amount of received light can be increased.
[0016]
In this case, as in the optical pickup device according to the third aspect, the specific order can be one of the +1 order and the −1 order.
[0017]
In each of the optical pickup devices according to the first to third aspects, as in the optical pickup device according to the fourth aspect, the polarization hologram can have a light collecting action. In such a case, the light receiving area of the emitted light amount detector can be reduced, and high-speed response can be improved.
[0018]
The invention according to claim 5 is an optical pickup device that irradiates light to recording surfaces of a plurality of types of information recording media and receives light reflected from the recording surfaces, wherein the plurality of types of information recording media are individually provided. A plurality of light sources which are provided correspondingly and selectively emit light beams having different wavelengths; an objective lens which collects the respective light beams on a recording surface of a corresponding information recording medium; and an objective lens which is emitted from the plurality of light sources. An optical system disposed on an optical path of a light beam toward the objective lens, the optical system including at least one polarization hologram for diffracting a part of each light beam, and guiding a return light beam reflected by the recording surface to a predetermined light receiving position; An optical pickup device comprising: a return light detector disposed at a light receiving position; and at least one output light amount detector that receives diffracted light of each wavelength from the at least one polarization hologram. .
[0019]
According to this, luminous fluxes (emitted luminous fluxes) emitted from the plurality of light sources are condensed on the recording surface of the corresponding information recording medium via the objective lens, and the return luminous flux reflected by the recording surface is returned to the return light detector. Is received at. Further, a part of the emitted light beam is diffracted by at least one polarization hologram, and is received by at least one emitted light amount detector. Here, since the polarization hologram has a different diffraction efficiency depending on the polarization state of the incident light, for example, the diffraction efficiency is high in the polarization direction of the output light beam, and the diffraction efficiency is high in the polarization direction of the return light beam. By setting to be low, even if the polarization hologram is arranged on the common optical path of the forward path and the return path, the light amount of the return light beam received by the return light detector is reduced regardless of the wavelength of the output light beam. There is no. That is, in any of the corresponding information recording media, the signal level and the S / N ratio of the output signal of the return light detector are not reduced. Furthermore, since a small-sized and inexpensive general-purpose product can be used as the polarization hologram and the emitted light amount detector, all information regarding the emission power of each light source can be output with good response without increasing the size and cost. It is possible to do.
[0020]
In this case, as in the optical pickup device described in claim 6, the polarization hologram can include a plurality of polarization holograms individually corresponding to the plurality of light sources.
[0021]
In this case, as in the optical pickup device according to claim 7, at least one of the plurality of polarization holograms has an incident angle of a light beam from a light source corresponding to the polarization hologram having a specific order of diffraction. The arrangement may be such that the incident angle when the light intensity is selectively increased substantially coincides with the incident angle. In such a case, most of the diffracted light diffracted by the polarization hologram can be received by the output light amount detector, so that the amount of light condensed on the recording surface does not decrease and the output light amount detector The amount of received light can be increased.
[0022]
In this case, as in the optical pickup device according to the eighth aspect, the specific order can be one of the +1 order and the −1 order.
[0023]
In each of the optical pickup devices according to the sixth to eighth aspects, as in the optical pickup device according to the ninth aspect, at least one of the plurality of polarization holograms has wavelength selectivity. Can be. In such a case, the light use efficiency can be improved.
[0024]
In each of the optical pickup devices according to the sixth to ninth aspects, as in the optical pickup device according to the tenth aspect, at least one of the plurality of polarization holograms has a condensing function. Can be. In such a case, the light receiving area of the output light amount detector that receives the diffracted light from the polarization hologram can be reduced, and the high-speed response can be improved.
[0025]
In each of the optical pickup devices according to claims 6 to 10, as in the optical pickup device according to claim 11, at least two of the plurality of polarization holograms are integrated. it can. In such a case, the number of parts in the assembling process is reduced, so that the assembling operation can be simplified and the operation cost can be reduced. In addition, by adjusting the position of each polarization hologram and integrating them, the assembling accuracy is improved, the adjustment operation can be simplified, and the operation cost can be reduced. Further, miniaturization of the optical pickup device can be promoted.
[0026]
In each of the optical pickup devices according to claims 6 to 11, as in the optical pickup device according to claim 12, diffracted lights from at least two polarization holograms among the plurality of polarization holograms each have the same output light amount. The light may be received by a detector. In such a case, the number of parts is reduced, and the cost of parts can be reduced. Further, it is possible to promote downsizing of the optical pickup device.
[0027]
In the optical pickup device according to the fifth aspect, as in the optical pickup device according to the thirteenth aspect, the polarization hologram may include a plurality of polarization holograms individually provided corresponding to at least two light sources of the plurality of light sources. It can include a polarization hologram having a diffraction region. In such a case, the number of polarization holograms is reduced, and the miniaturization of the optical pickup device can be promoted.
[0028]
According to a fourteenth aspect of the present invention, there is provided an optical disc apparatus which irradiates light onto a recording surface of an information recording medium and performs at least reproduction among information recording, reproduction, and erasure. An optical disc device comprising: the optical pickup device according to claim 1; and a processing device that performs at least reproduction among information recording, reproduction, and erasure using an output signal from the optical pickup device.
[0029]
According to this, it is possible to suppress the fluctuation of the light emission power of the light source based on the output signal of the optical pickup device according to any one of the first to thirteenth aspects. Therefore, as a result, it is possible to perform an access including at least reproduction among information recording, reproduction, and erasure on the information recording medium at a high speed and with high accuracy.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
<< 1st Embodiment >>
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of an optical disk device according to a first embodiment of the present invention.
[0031]
The optical disk device 20 shown in FIG. 1 includes a spindle motor 22 for rotating and driving the optical disk 15, an optical pickup device 23, a laser control circuit 24, an encoder 25, a motor driver 27, a reproduction signal processing circuit 28, a servo controller 33, A buffer RAM 34, a buffer manager 37, an interface 38, a ROM 39, a CPU 40, a RAM 41, an APC circuit 42, and the like are provided. Note that the arrows in FIG. 1 indicate typical flows of signals and information, and do not indicate all of the connection relationships of the respective blocks. In the first embodiment, an information recording medium conforming to the DVD standard is used as the optical disc 15 as an example.
[0032]
The optical pickup device 23 is a device for irradiating the recording surface on which the spiral or concentric tracks of the optical disk 15 are formed with laser light and receiving the reflected light from the recording surface. The configuration and the like of the optical pickup device 23 will be described later in detail.
[0033]
The reproduction signal processing circuit 28 detects a wobble signal, an RF signal, a servo signal (a focus error signal, a track error signal) and the like based on an output signal from the optical pickup device 23. Then, the reproduction signal processing circuit 28 extracts ADIP (Address In Pregroove) information, a synchronization signal, and the like from the wobble signal. The extracted ADIP information is output to the CPU 40, and the synchronization signal is output to the encoder 25. Further, the reproduction signal processing circuit 28 performs demodulation processing, error correction processing, and the like on the RF signal, and stores the RF signal in the buffer RAM 34 via the buffer manager 37. The servo signal is output from the reproduction signal processing circuit 28 to the servo controller 33.
[0034]
The servo controller 33 generates various control signals for controlling the optical pickup device 23 based on the servo signals, and outputs the control signals to the motor driver 27.
[0035]
The motor driver 27 controls the optical pickup device 23 and the spindle motor 22 based on a control signal from the servo controller 33 and an instruction from the CPU 40.
[0036]
The APC circuit 42 generates a control signal for suppressing a change in light emission power based on a light amount monitor signal from the optical pickup device 23 described later, and outputs the control signal to the laser control circuit 24.
[0037]
The encoder 25 fetches the data stored in the buffer RAM 34 via the buffer manager 37 based on an instruction from the CPU 40, performs 8-16 modulation and addition of an error correction code, and converts a write signal to the optical disk 15 into a signal. At the same time, the write signal is output to the laser control circuit 24 in synchronization with the synchronizing signal from the reproduction signal processing circuit 28.
[0038]
The laser control circuit 24 controls the emission power of the laser light emitted from the optical pickup device 23 based on a write signal from the encoder 25 and an instruction from the CPU 40. Further, the laser control circuit 24 performs feedback control of the emission power of the laser light based on a control signal from the APC circuit 42.
[0039]
The buffer manager 37 manages the input and output of data to and from the buffer RAM 34, and notifies the CPU 40 when the accumulated data amount reaches a predetermined value.
[0040]
The interface 38 is a two-way communication interface with a host (for example, a personal computer), and conforms to a standard interface such as ATAPI (AT Attachment Packet Interface) and SCSI (Small Computer System Interface).
[0041]
The ROM 39 stores a program described in a code decodable by the CPU 40. Then, the CPU 40 controls the operation of each unit according to the program stored in the ROM 39, and temporarily stores data and the like necessary for the control in the RAM 41.
[0042]
Next, the configuration and the like of the optical pickup device 23 will be described with reference to FIGS. 2 (A) and 2 (B). As shown in FIG. 2A, the optical pickup device 23 includes a light receiving / emitting module 51, a signal hologram 56, a collimator lens 52, a λ / 4 plate 55, an objective lens 60, a monitor hologram 58, and a monitor light receiving element. 57, a drive system (a focusing actuator, a tracking actuator, and a seek motor (all not shown)) and the like.
[0043]
Here, the light receiving / emitting module 51 includes a semiconductor laser 51a as a light source that emits a light beam having a wavelength of 660 nm, and a light receiver 51b as a photodetector that receives the light beam reflected by the optical disc 15 as a return light beam. It is configured. In the first embodiment, the maximum intensity emission direction of the light beam emitted from the semiconductor laser 51a is defined as the + X direction. Further, as an example, it is assumed that a light beam of polarized light (P-polarized light) parallel to the incident surface of the signal hologram 56 is emitted from the semiconductor laser 51a. The light receiver 51b is arranged at a predetermined position separated from the semiconductor laser 51a by a predetermined distance in the -Z direction.
[0044]
As the light receiver 51b, a four-divided light receiving element is used as in the ordinary optical disk device, and outputs a signal including wobble signal information, reproduction data information, focus error information, track error information, and the like to the reproduction signal processing circuit 28. I do.
[0045]
The signal hologram 56 is arranged on the + X side of the light receiving / emitting module 51, and branches the return light beam reflected by the optical disk 15 from the common optical path of the forward path and the return path toward the light receiving surface of the light receiver 51b. The signal hologram 56 has a polarization property whose diffraction efficiency varies depending on the polarization direction of the incident light beam. Here, as described above, the P-polarized light beam is emitted from the semiconductor laser 51a, and the return light beam becomes the S-polarized light beam. Therefore, the signal hologram 56 has a low diffraction efficiency with respect to the P-polarized light beam. , S-polarized light is set to have high diffraction efficiency. The signal hologram 56 and the light emitting / receiving module 51 are integrated.
[0046]
The collimating lens 52 is arranged on the + X side of the signal hologram 56, and converts a light beam transmitted through the signal hologram 56 into substantially parallel light.
[0047]
The monitor hologram 58 is disposed on the + X side of the collimator lens 52, and a part of the light beam transmitted through the collimator lens 52 is received by the monitor light receiver disposed at a predetermined position away from the common optical path of the forward path and the return path. The light is diffracted in the direction of the light receiving surface of the element 57 and is focused on the light receiving surface of the monitoring light receiving element 57. The monitor hologram 58 has a polarization property whose diffraction efficiency varies depending on the polarization direction of the incident light beam. Here, since the P-polarized light beam is emitted from the semiconductor laser 51a and the return light beam is an S-polarized light beam, the monitor hologram 58 has a high diffraction efficiency with respect to the P-polarized light beam, It is set so as to have a low diffraction efficiency for a light beam. The monitor hologram 58 has grooves formed in a predetermined pattern for adding a light condensing function, as shown in FIG. 2B as an example. In addition, the diffraction efficiency of the monitor hologram 58 greatly changes depending on the incident angle of light, and the diffraction efficiency is maximized at a specific incident angle (the incident angle when the Bragg condition is satisfied), similarly to a normal volume hologram. It becomes. In the monitor hologram 58, as shown in FIG. 3A as an example, when the incident angle is θ1 (here, about 30 degrees), the + 1st-order diffracted light L ₊₁ Is almost maximum. Therefore, in the first embodiment, as shown in FIG. 3B, the monitor hologram 58 is arranged such that the incident angle of the light beam transmitted through the collimator lens 52 substantially matches θ1. Note that L in FIGS. 3A and 3B ₀ Denotes the zero-order light, and light L _-1 Indicates -1st-order diffracted light.
[0048]
A normal light receiving element is used as the monitoring light receiving element 57. The monitoring light receiving element 57 is provided for monitoring the light emission power of the semiconductor laser 51a, and outputs a signal including information on the light amount of the light beam emitted from the semiconductor laser 51a to the APC circuit 42 as a light amount monitor signal. .
[0049]
Returning to FIG. 2, the λ / 4 plate 55 is arranged on the + X side of the monitor hologram 58 and gives an optical phase difference to a light beam transmitted through the monitor hologram 58. On the + X side of the λ / 4 plate 55, the objective lens 60 is arranged. The objective lens 60 condenses the light flux transmitted through the λ / 4 plate 55 to form a light spot on the recording surface of the optical disk 15.
[0050]
The operation of the optical pickup device 23 configured as described above will be briefly described. The P-polarized light beam emitted from the semiconductor laser 51a enters the signal hologram 56. Since the signal hologram 56 has a low diffraction efficiency with respect to the P-polarized light beam, most of the light beam emitted from the semiconductor laser 51a passes through the signal hologram 56. The light beam transmitted through the signal hologram 56 is converted into substantially parallel light by the collimator lens 52, and then enters the monitor hologram 58. Since the light beam incident on the monitor hologram 58 is a P-polarized light beam, a part of the light beam is diffracted by the monitor hologram 58, and the + 1st-order diffracted light is condensed on the light receiving surface of the monitor light receiving element 57. From the monitoring light receiving element 57, a signal corresponding to the amount of received light is output to the APC circuit 42. On the other hand, the light beam transmitted through the monitor hologram 58 is circularly polarized by the λ / 4 plate 55, and then condensed as a minute spot on the recording surface of the optical disk 15 via the objective lens 60.
[0051]
The reflected light reflected on the recording surface of the optical disk 15 becomes a circularly polarized light flux that is opposite to the outward path, and is converted into substantially parallel light again by the objective lens 60 as a return light flux. The returned light beam is converted into linearly polarized light (here, S-polarized light) orthogonal to the outward path by the λ / 4 plate 55, and then enters the monitor hologram 58. Since the light beam incident on the monitor hologram 58 is an S-polarized light beam, most of the light beam passes through the monitor hologram 58 and enters the signal hologram 56 via the collimator lens 52. In the signal hologram 56, since the diffraction efficiency with respect to the S-polarized light beam is large, a part of the return light beam is diffracted by the signal hologram 56 and received by the light receiver 51b. Each light receiving element constituting the light receiver 51b outputs a signal corresponding to the amount of received light to the reproduction signal processing circuit 28.
[0052]
Here, a recording process in the optical disc device 20 will be described.
[0053]
Upon receiving the recording request command from the host, the CPU 40 outputs a control signal for controlling the rotation of the spindle motor 22 to the motor driver 27 based on the specified recording speed, and receives the recording request command from the host. This is notified to the reproduction signal processing circuit 28. Further, the CPU 40 instructs the buffer manager 37 to store the user data received from the host in the buffer RAM 34.
[0054]
When the rotation of the optical disk 15 reaches a predetermined linear velocity, the reproduction signal processing circuit 28 detects a focus error signal and a track error signal based on the output signal of the light receiver 51b, and outputs the signals to the servo controller 33. The servo controller 33 drives the focusing actuator and the tracking actuator of the optical pickup device 23 via the motor driver 27 based on the focus error signal and the track error signal from the reproduction signal processing circuit 28 to correct the focus shift and the track shift. I do. That is, focus control and tracking control are performed. Note that the focus control and the tracking control are performed as needed until the recording process ends. Further, the reproduction signal processing circuit 28 acquires ADIP information based on the output signal of the light receiver 51b and notifies the CPU 40 of the information. Note that the reproduction signal processing circuit 28 acquires ADIP information at predetermined timings until the recording processing ends, and notifies the CPU 40 of the ADIP information.
[0055]
The CPU 40 outputs a signal for controlling the seek motor of the optical pickup device 23 to the motor driver 27 based on the ADIP information so that the optical pickup device 23 is located at the writing start point. Further, upon receiving from the buffer manager 37 a notification that the amount of user data stored in the buffer RAM 34 has exceeded a predetermined value, the CPU 40 instructs the encoder 25 to generate a write signal. Further, when the CPU 40 determines that the position of the optical pickup device 23 is the writing start point based on the ADIP information, the CPU 40 notifies the encoder 25. Thus, the user data is recorded on the optical disk 15 via the encoder 25, the laser control circuit 24, and the optical pickup device 23.
[0056]
Next, a reproduction process in the optical disk device 20 will be described.
[0057]
When receiving the command of the reproduction request from the host, the CPU 40 outputs a control signal for controlling the rotation of the spindle motor 22 to the motor driver 27 based on the reproduction speed, and performs the reproduction signal processing to the effect that the reproduction request command is received. The circuit 28 is notified. The reproduction signal processing circuit 28 corrects the focus shift and the track shift as in the case of the recording processing, and notifies the CPU 40 of the ADIP information.
[0058]
The CPU 40 outputs a signal for controlling the seek motor of the optical pickup device 23 to the motor driver 27 based on the ADIP information so that the optical pickup device 23 is located at the reading start point. When the CPU 40 determines that the position of the optical pickup device 23 is the reading start point based on the ADIP information, it notifies the reproduction signal processing circuit 28.
[0059]
The reproduction signal processing circuit 28 detects the RF signal based on the output signal from the light receiver 51b, performs demodulation processing, error correction processing, and the like, and then stores the signal in the buffer RAM 34. The buffer manager 37 transfers the reproduced data stored in the buffer RAM 34 to the host via the interface 38 when the data is prepared as sector data.
[0060]
Further, the APC circuit 42 outputs a control signal for suppressing the fluctuation of the light emission power to the laser control circuit 24 as needed based on the light amount monitor signal from the monitoring light receiving element 57 until the recording processing and the reproduction processing are completed.
[0061]
As is apparent from the above description, in the optical disc device 20 according to the first embodiment, a processing device is realized by the reproduction signal processing circuit 28, the CPU 40, and the program executed by the CPU 40. In the first embodiment, at least a part of the processing device realized by the processing according to the program by the CPU 40 may be configured by hardware, or all of the processing device may be configured by hardware. good.
[0062]
As described above, according to the optical pickup device according to the first embodiment, the light beam (emitted light beam) emitted from the light source is condensed on the recording surface of the optical disk via the objective lens, and reflected on the recording surface. The returned light beam is received by the light receiver. Further, a part of the emitted light beam is diffracted by the monitor hologram and received by the monitor light receiving element. Since the monitor hologram is arranged so that the outgoing light flux is incident at an angle at which the amount of the + 1st-order diffracted light is substantially maximum, most of the diffracted light can be received by the monitor light receiving element. Therefore, it is possible to increase the amount of light received by the monitoring light receiving element without causing a decrease in the amount of light focused on the recording surface. Further, since the monitoring hologram has a different diffraction efficiency depending on the polarization state of the incident light, even if it is arranged in the common optical path of the forward path and the return path, it does not reduce the light amount of the return light beam received by the light receiver. . That is, the signal level and the S / N ratio of the output signal of the light receiving device are not reduced. Furthermore, as the monitor hologram and the monitor light receiving element, general-purpose products that are small and inexpensive can be used. That is, it is possible to output information on the light emission power of the light source with good responsiveness without increasing the size and cost.
[0063]
Further, according to the first embodiment, since the monitoring hologram is provided with a condensing function, the area of the monitoring light receiving element can be reduced, and the high-speed response can be improved.
[0064]
Further, according to the optical disc device of the first embodiment, since the light emission power of the light source can be detected with high responsiveness and high sensitivity, it is possible to perform highly accurate APC control. Further, the detection of the light emission power of the light source does not involve a decrease in the amount of the return light beam received by the light receiver, so that the servo control can be performed with high accuracy. Therefore, as a result, it is possible to accurately and stably access the optical disc at a high speed. Further, the miniaturization and weight reduction of the optical pickup device can promote the miniaturization of the optical disc device itself and the reduction of power consumption. For example, when the optical pickup device is used for portable use, it is easy to carry and has a long time. Can be used.
[0065]
In the first embodiment, a polarization beam splitter may be used instead of the monitor hologram 58. However, in this case, a condensing lens for condensing a light beam between the polarization beam splitter and the monitoring light receiving element 57 is required.
[0066]
In the first embodiment, the + 1st-order diffracted light L ₊₁ Has been described in which the incident angle of the light flux transmitted through the collimator lens 52 to the monitor hologram 58 is set so that the light amount of the light is substantially maximum. _-1 The incident angle of the light beam transmitted through the collimating lens 52 to the monitor hologram 58 may be set so that the light amount of the light beam becomes substantially maximum. However, in this case, it is necessary to change the arrangement of the monitoring light receiving element 57 correspondingly.
[0067]
<< 2nd Embodiment >>
Next, a second embodiment of the present invention will be described with reference to FIGS.
[0068]
In the second embodiment, as shown in FIG. 4A, an optical pickup device 43 including two semiconductor lasers that emit light beams having different wavelengths is used instead of the above-described pickup device 23. It has features. The optical disk device according to the second embodiment includes an information recording medium (hereinafter abbreviated as “CD system”) compliant with a CD standard and an information recording medium (hereinafter “DVD system”) compliant with a DVD system. ) Is used as the optical disc 15. In the following, the same reference numerals are used for components that are substantially the same as or equivalent to those of the above-described first embodiment, and description thereof will be simplified or omitted.
[0069]
The optical pickup device 43 includes, as shown in FIG. 4A, a light receiving / emitting module 61, a first signal hologram 66a, a second signal hologram 66b, a collimating lens 62, a λ / 4 plate 65, an objective lens. 70, a monitor hologram 58, a first monitor light receiving element 67a, a second monitor light receiving element 67b, a drive system (a focusing actuator, a tracking actuator, and a seek motor (all not shown)), and the like.
[0070]
The light receiving / emitting module 61 was reflected by the optical disk 15 as a first semiconductor laser 61a as a light source for emitting a light beam having a wavelength of 660 nm, a second semiconductor laser 61b as a light source for emitting a light beam having a wavelength of 785 nm. And a light receiver 61c as a photodetector for receiving the light beam as a return light beam. The semiconductor lasers are arranged close to each other. In the second embodiment, the maximum intensity emission direction of the light beam emitted from each semiconductor laser is defined as the + X direction. As an example, it is assumed that each semiconductor laser emits a light beam of polarized light (P-polarized light) parallel to the incident surface of each signal hologram. The light receiver 61c is arranged at a predetermined position separated from the second semiconductor laser 61b by a predetermined distance in the -Z direction. The first semiconductor laser 61a is selected when the optical disk 15 is a DVD system, and the second semiconductor laser 61b is selected when the optical disk 15 is a CD system.
[0071]
The first signal hologram 66a is disposed on the + X side of the light receiving / emitting module 61, and transmits the return light beam having a wavelength of 660 nm reflected by the optical disk 15 from the common optical path of the forward path and the return path to the light receiving surface of the light receiver 61c. Branch to The second signal hologram 66b is disposed on the + X side of the first signal hologram 66a, and transmits the return light beam having a wavelength of 785 nm reflected by the optical disk 15 from the common optical path of the forward path and the return path to the light receiver 61c. Branches in the direction of the light receiving surface. Each signal hologram has a polarization property whose diffraction efficiency varies depending on the polarization direction of the incident light beam. Here, as described above, the P-polarized light beam is emitted from each semiconductor laser, and the return light beam is an S-polarized light beam. Therefore, each signal hologram has a low diffraction efficiency with respect to the P-polarized light beam. , S-polarized light is set to have high diffraction efficiency. The first signal hologram 66a is optimized for a light beam having a wavelength of 660 nm, and the second signal hologram 66b is optimized for a light beam having a wavelength of 785 nm. Further, the first signal hologram 66a, the second signal hologram 66b, and the light emitting / receiving module 61 are integrated.
[0072]
The collimating lens 62 is arranged on the + X side of the second signal hologram 66b, and converts the light beam transmitted through the second signal hologram 66b into substantially parallel light.
[0073]
The monitor hologram 68 is disposed on the + X side of the collimator lens 62, and a part of the light beam having a wavelength of 660 nm transmitted through the collimator lens 62 is disposed at a predetermined position away from the common optical path of the forward path and the return path. While diffracting and condensing light in the direction of the light receiving surface of the first monitoring light receiving element 67a, a part of the light flux having a wavelength of 785 nm transmitted through the collimating lens 62 is located at a predetermined position away from the common optical path of the forward path and the return path. The light is diffracted and condensed in the direction of the light receiving surface of the second monitor light receiving element 67b. The monitor hologram 68 has a polarization property whose diffraction efficiency varies depending on the polarization direction of the incident light beam. Here, a P-polarized light beam is emitted from each semiconductor laser, and the returned light beam is an S-polarized light beam. Therefore, the monitoring hologram 68 has a high diffraction efficiency with respect to the P-polarized light beam, It is set so as to have a low diffraction efficiency for a light beam. As an example, as shown in FIG. 5, the monitor hologram 68 has a + 1st-order diffracted light Ld of a light beam having a wavelength of 660 nm when the incident angle is θ2 (about 14 degrees here). ₊₁ Is almost maximum, and the + 1st-order diffracted light Lc of a light beam having a wavelength of 785 nm when the incident angle is θ3 (about 16 degrees here) ₊₁ Is almost maximum. Therefore, in the second embodiment, the monitor hologram 68 is arranged so that the incident angle of the light beam transmitted through the collimator lens 62 is between θ2 and θ3 (for example, 15 degrees). Note that Ld in FIG. _-1 Indicates a -1st-order diffracted light beam having a wavelength of 660 nm, and Lc _-1 Indicates a -1st-order diffracted light beam having a wavelength of 785 nm.
[0074]
Normal light receiving elements are used for the first monitoring light receiving element 67a and the second monitoring light receiving element 67b, respectively. The first monitoring light receiving element 67a is provided for monitoring the light emission power of the first semiconductor laser 61a, and monitors a signal including information on the light amount of the light beam emitted from the first semiconductor laser 61a by a light amount monitor. The signal is output to the APC circuit 42 as a signal. The second monitoring light receiving element 67b is provided to monitor the light emission power of the second semiconductor laser 61b, and monitors a signal including information on the light amount of the light beam emitted from the second semiconductor laser 61b. The signal is output to the APC circuit 42 as a signal.
[0075]
Returning to FIG. 4A, the λ / 4 plate 65 is arranged on the + X side of the monitor hologram 68, and gives an optical phase difference to a light beam transmitted through the monitor hologram 68. On the + X side of the λ / 4 plate 65, the objective lens 70 is arranged. The objective lens 70 condenses the light flux transmitted through the λ / 4 plate 65, and forms a light spot on the recording surface of the optical disk 15.
[0076]
The operation of the optical pickup device 43 configured as described above will be briefly described. First, the case where the optical disk 15 is a DVD system will be described with reference to FIG.
[0077]
The P-polarized light beam emitted from the first semiconductor laser 61a enters the first signal hologram 66a. In the first signal hologram 66a, since the diffraction efficiency with respect to the P-polarized light beam is small, most of the light beam emitted from the first semiconductor laser 61a passes through the first signal hologram 66a. The light beam transmitted through the first signal hologram 66a enters the second signal hologram 66b. In the second signal hologram 66b, since the diffraction efficiency with respect to the P-polarized light beam is small, most of the light beam transmitted through the first signal hologram 66a is transmitted through the second signal hologram 66b. The light beam transmitted through the second signal hologram 66b is converted into substantially parallel light by the collimator lens 62, and then enters the monitor hologram 68. Since the light beam incident on the monitor hologram 68 is a P-polarized light beam, a part of the light beam is diffracted by the monitor hologram 68, and the + 1st-order diffracted light is condensed on the light receiving surface of the first monitor light receiving element 67a. You. From the first monitoring light receiving element 67a, a signal corresponding to the amount of received light is output to the APC circuit 42. On the other hand, the light beam transmitted through the monitor hologram 68 is converted into circularly polarized light by the λ / 4 plate 65 and then collected as a minute spot on the recording surface of the optical disk 15 via the objective lens 70.
[0078]
The reflected light reflected on the recording surface of the optical disk 15 becomes a circularly-polarized light beam in the opposite direction to the outward path, and is again converted into substantially parallel light by the objective lens 70 as a return light beam. The return light beam is converted into linearly polarized light (here, S-polarized light) orthogonal to the outward path by the λ / 4 plate 65 and then enters the monitor hologram 68. Since the light beam incident on the monitor hologram 68 is an S-polarized light beam, most of the light beam passes through the monitor hologram 68 and is incident on the second signal hologram 66b via the collimator lens 62. Since the second signal hologram 66b is optimized for a light beam having a wavelength of 785 nm, most of the return light beam passes through the second signal hologram 66b and enters the first signal hologram 66a. I do. The first signal hologram 66a is optimized for a light beam having a wavelength of 660 nm, and has a high diffraction efficiency with respect to the s-polarized light beam. Therefore, a part of the return light beam is diffracted by the first signal hologram 66a. The light is received by the light receiver 61c. Each light receiving element constituting the light receiver 61c outputs a signal corresponding to the amount of received light to the reproduction signal processing circuit 28.
[0079]
Next, the case where the optical disk 15 is a CD system will be described with reference to FIG.
[0080]
The P-polarized light beam emitted from the second semiconductor laser 61b enters the first signal hologram 66a. In the first signal hologram 66a, since the diffraction efficiency with respect to the P-polarized light beam is small, most of the light beam emitted from the second semiconductor laser 61b passes through the first signal hologram 66a. The light beam transmitted through the first signal hologram 66a enters the second signal hologram 66b. In the second signal hologram 66b, since the diffraction efficiency with respect to the P-polarized light beam is small, most of the light beam transmitted through the first signal hologram 66a is transmitted through the second signal hologram 66b. The light beam transmitted through the second signal hologram 66b is converted into substantially parallel light by the collimator lens 62, and then enters the monitor hologram 68. Since the light beam incident on the monitor hologram 68 is a P-polarized light beam, a part of the light beam is diffracted by the monitor hologram 68, and the + 1st-order diffracted light is condensed on the light receiving surface of the second monitor light receiving element 67b. You. From the second monitoring light receiving element 67b, a signal corresponding to the amount of received light is output to the APC circuit 42. On the other hand, the light beam transmitted through the monitor hologram 68 is converted into circularly polarized light by the λ / 4 plate 65 and then collected as a minute spot on the recording surface of the optical disk 15 via the objective lens 70.
[0081]
The reflected light reflected on the recording surface of the optical disk 15 becomes a circularly-polarized light beam in the opposite direction to the outward path, and is again converted into substantially parallel light by the objective lens 70 as a return light beam. The return light beam is converted into linearly polarized light (here, S-polarized light) orthogonal to the outward path by the λ / 4 plate 65 and then enters the monitor hologram 68. Since the light beam incident on the monitor hologram 68 is an S-polarized light beam, most of the light beam passes through the monitor hologram 68 and is incident on the second signal hologram 66b via the collimator lens 62. Since the second signal hologram 66b is optimized for a light beam having a wavelength of 785 nm and has a high diffraction efficiency with respect to the S-polarized light beam, a part of the return light beam is diffracted by the second signal hologram 66b. The light is incident on the first signal hologram 66a. Since the first signal hologram 66a is optimized for a light beam having a wavelength of 660 nm, most of the diffracted light from the second signal hologram 66b is transmitted through the first signal hologram 66a and received. The light is received by the device 61c. Each light receiving element constituting the light receiver 61c outputs a signal corresponding to the amount of received light to the reproduction signal processing circuit 28.
[0082]
Whether the optical disk 15 is of the CD type or the DVD type can be determined from the intensity of light reflected from the recording surface. Usually, this determination is made by the CPU 40 when the optical disk 15 is loaded at a predetermined position of the optical disk device 20. In addition, the type of the optical disc 15 can be determined based on TOC (Table Of Contents) information, PMA (Program Memory Area) information, a wobble signal, and the like, which are recorded in the optical disc 15 in advance. Then, the determination result is notified from the CPU 40 to the laser control circuit 24, and the laser control circuit 24 selects one of the first semiconductor laser 61a and the second semiconductor laser 61b. The determination result is also notified to other circuits or the like that perform processing according to the type of the optical disk.
[0083]
In the optical disk device according to the second embodiment, when the optical disk 15 is a DVD system, recording of data on the optical disk 15 and reproduction of data recorded on the optical disk 15 are performed in the same manner as in the first embodiment. Is performed. When the optical disk 15 is of the CD type, recording and reproduction are performed in substantially the same procedure as that of the DVD type, although there are some slightly different processes from those of the DVD type.
[0084]
As is clear from the above description, in the optical disc device according to the second embodiment, a processing device is realized by the reproduction signal processing circuit 28, the CPU 40, and the program executed by the CPU 40. In the second embodiment, at least a part of the processing device realized by the processing according to the program by the CPU 40 may be configured by hardware, or the entire processing device may be configured by hardware. good.
[0085]
As described above, according to the optical pickup device according to the second embodiment, the luminous flux (emitted luminous flux) emitted from each light source is focused on the recording surface of the corresponding optical disc via the objective lens, respectively. The return light beam reflected by the recording surface is received by the light receiver. Further, a part of the emitted light beam is diffracted by the monitor hologram and received by the corresponding monitor light receiving element. Since the monitor hologram is arranged so that the outgoing light beam enters at an angle at which the light amount of the + 1st-order diffracted light is substantially maximum, the first embodiment can be performed regardless of whether the optical disk is a CD system or a DVD system. The same effects as those of the optical pickup device according to the embodiment can be obtained.
[0086]
Further, according to the second embodiment, since the hologram for monitoring is provided with a condensing function, the area of the light receiving element for monitoring can be reduced, and the high-speed response can be improved.
[0087]
Further, according to the optical disk device according to the second embodiment, the light emission power of the light source can be detected with high sensitivity. The same effect as that of the optical disk device can be obtained.
[0088]
In the second embodiment, a polarization beam splitter may be used instead of the monitor hologram 68. However, in this case, a condensing lens for condensing a light beam is required between the polarizing beam splitter and each monitoring light receiving element.
[0089]
Further, in the second embodiment, as shown in FIGS. 6A and 6B, instead of the monitor hologram 68, the monitor hologram 68a corresponding to a light beam having a wavelength of 660 nm and the monitor hologram 68a have the same wavelength. The monitor hologram 68b corresponding to the 785 nm light beam may be used. In this case, by installing the monitor hologram 68a having a small diffraction angle on the light source side and the monitor hologram 68b having a large diffraction angle on the optical disk side, the first monitor light receiving element 67a and the second monitor hologram 68a are provided. Instead of the light receiving element 67b, one monitor light receiving element 67 can receive the light flux of each wavelength. That is, it is possible to share the monitoring light receiving element. Thereby, miniaturization of the optical pickup device can be promoted. Further, each monitor hologram may be integrated. As a result, the assembling work can be simplified, and the reduction of the working cost can be promoted. In this case, each monitor hologram may have wavelength selectivity. Thereby, light use efficiency can be improved. Alternatively, the incident angle of the light beam having a wavelength of 660 nm incident on the monitor hologram 68a and the incident angle of the light beam having a wavelength of 785 nm incident on the monitor hologram 68b may be individually set.
[0090]
In this case, as shown in FIGS. 7A and 7B as an example, a monitor hologram corresponding to a light beam having a wavelength of 660 nm and a monitor hologram corresponding to a light beam having a wavelength of 785 nm are used. They may be integrated. In the monitor hologram shown in FIG. 7A, unevenness corresponding to a light beam having a wavelength of 660 nm is formed on one surface of the organic stretched film YM having optical anisotropy, and the wavelength is formed on the other surface. Irregularities corresponding to the 785 nm light flux are formed, and the respective surfaces on which the irregularities are formed are bonded to the glass substrate GP via an adhesive AD having a predetermined refractive index. The monitor hologram shown in FIG. 7B has an optically anisotropic organic stretched film YM1 in which irregularities corresponding to a light beam having a wavelength of 660 nm are formed, and an unevenness corresponding to a light beam having a wavelength of 785 nm. Is bonded to the organic stretched film YM2 having optical anisotropy via an adhesive AD having a predetermined refractive index. Thereby, the manufacturing process of the monitor hologram can be simplified, and the size of the optical pickup device can be promoted.
[0091]
Further, in this case, as shown in FIGS. 8A and 8B as an example, a diffraction region Rdvd corresponding to a light beam having a wavelength of 660 nm and a diffraction region Rcd corresponding to a light beam having a wavelength of 785 nm are used. A monitor hologram may be used. Thereby, miniaturization of the optical pickup device can be promoted.
[0092]
In the second embodiment, the case has been described where the incident angle of the light flux transmitted through the collimator lens 62 to the signal hologram 68 is set such that the light amount of each + 1st-order diffracted light is substantially maximum. However, the angle of incidence of the light beam transmitted through the collimator lens 62 on the signal hologram 68 may be set so that the light amount of each of the −1st-order diffracted light is substantially maximized. However, in this case, it is necessary to change the arrangement of the monitoring light receiving elements 67a and 67b accordingly.
[0093]
In the second embodiment, the case where the wavelength of the light beam emitted from the light source is 660 nm and 785 nm has been described, but the present invention is not limited to this. Instead of any one of the light sources, for example, a light source that emits a light beam having a wavelength of 405 nm may be used.
[0094]
Furthermore, in the above-described second embodiment, the case has been described in which the light beam emitted from the light source has two types of wavelengths. However, the present invention is not limited to this, and three or more types may be used.
[0095]
Further, in each of the above embodiments, the optical disk device capable of recording and reproducing information has been described. However, the present invention is not limited to this, and any optical disk device capable of at least reproducing among information recording, reproduction, and erasing may be used.
[0096]
【The invention's effect】
As described above, according to the optical pickup device of the present invention, there is an effect that information on the light emission power of the light source can be output with good responsiveness without increasing the size and cost.
[0097]
Further, according to the optical disc device of the present invention, there is an effect that high-speed access to the information recording medium can be performed accurately and stably.
[0098]
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of an optical disk device according to a first embodiment of the present invention.
FIG. 2A is a diagram illustrating a schematic configuration of an optical system in an optical pickup device according to a first embodiment of the present invention, and FIG. 2B is a diagram illustrating a monitor in FIG. 2A; It is a figure for explaining a hologram for use.
FIG. 3A is a diagram for explaining the relationship between the incident angle of a light beam and the amount of diffracted light in the monitor hologram of FIG. 2B, and FIG. It is a figure for explaining the arrangement state of the hologram for use.
FIGS. 4A and 4B are diagrams each showing a schematic configuration of an optical system in an optical pickup device according to a second embodiment of the present invention.
5A and 5B are diagrams for explaining the relationship between the incident angle of a light beam and the amount of diffracted light in the monitoring hologram of FIGS. 4A and 4B, respectively.
FIGS. 6A and 6B are diagrams illustrating a modification of the optical pickup device according to the second embodiment of the present invention.
FIGS. 7A and 7B are diagrams illustrating a first modified example of the monitor hologram in the optical pickup device according to the second embodiment of the present invention.
FIG. 8
FIGS. 8A and 8B are diagrams illustrating a second modified example of the monitor hologram in the optical pickup device according to the second embodiment of the present invention.
[Explanation of symbols]
15 optical disk (information recording medium), 20 optical disk device, 23 optical pickup device, 28 reproduction signal processing circuit (part of processing device), 40 CPU (part of processing device), 43 optical pickup device 51a: semiconductor laser (light source), 51b: light receiver (return light detector), 57: monitor light receiving element (output light amount detector), 58: monitor hologram (polarization hologram), 60: objective lens, 61a ... First semiconductor laser (light source), 61b: second semiconductor laser (light source), 61c: light receiver (return light detector), 67a, 67b: light receiving element for monitor (emission light amount detector), 68: monitor Hologram (polarization hologram), 70 ... objective lens.

Claims (14)

An optical pickup device that irradiates light to a recording surface of an information recording medium and receives reflected light from the recording surface,
A light source;
An objective lens for condensing a light beam emitted from the light source on the recording surface; and a polarized light disposed on an optical path of the light beam emitted from the light source and traveling toward the objective lens, and diffracting a part of the light beam in a predetermined direction. An optical system that includes a hologram and guides a return light beam reflected by the recording surface to a predetermined light receiving position;
A return light detector arranged at the light receiving position;
An output light amount detector that receives a light beam diffracted by the polarization hologram. The polarization hologram, wherein an incident angle of the light beam with respect to the polarization hologram is set so as to substantially coincide with an incident angle when the intensity of diffracted light of a specific order is selectively increased. 2. The optical pickup device according to 1. The optical pickup device according to claim 2, wherein the specific order is one of +1 order and −1 order. The optical pickup device according to any one of claims 1 to 3, wherein the polarization hologram has a condensing function. An optical pickup device that irradiates light onto a recording surface of a plurality of types of information recording media and receives light reflected from the recording surface,
A plurality of light sources provided individually corresponding to the plurality of information recording media and selectively emitting light beams having different wavelengths;
An objective lens for condensing each light beam on a recording surface of a corresponding information recording medium, and at least diffracting a part of each light beam that is arranged on an optical path of a light beam emitted from the plurality of light sources and directed toward the objective lens. An optical system including one polarization hologram and guiding a return light beam reflected by the recording surface to a predetermined light receiving position;
A return light detector arranged at the light receiving position;
At least one outgoing light amount detector for respectively receiving diffracted light of each wavelength from the at least one polarization hologram. The optical pickup device according to claim 5, wherein the polarization hologram includes a plurality of polarization holograms individually corresponding to the plurality of light sources. At least one polarization hologram of the plurality of polarization holograms has an incident angle of a light beam from a light source corresponding to the polarization hologram substantially coincides with an incident angle when the intensity of the diffracted light of a specific order is selectively increased. The optical pickup device according to claim 6, wherein the optical pickup device is arranged as follows. The optical pickup device according to claim 7, wherein the specific order is one of +1 order and -1 order. The optical pickup device according to any one of claims 6 to 8, wherein at least one of the plurality of polarization holograms has wavelength selectivity. The optical pickup device according to claim 6, wherein at least one of the plurality of polarization holograms has a condensing function. The optical pickup device according to claim 6, wherein at least two polarization holograms among the plurality of polarization holograms are integrated. The optical pickup device according to any one of claims 6 to 11, wherein diffracted lights from at least two polarization holograms of the plurality of polarization holograms are received by the same output light amount detector. . 6. The optical pickup device according to claim 5, wherein the polarization hologram includes a polarization hologram having a plurality of diffraction regions provided individually corresponding to at least two of the plurality of light sources. An optical disc device that irradiates light onto a recording surface of an information recording medium and performs at least reproduction of information recording, reproduction, and erasing,
An optical pickup device according to any one of claims 1 to 13, and
An optical disk device comprising: a processing device that performs at least reproduction of information recording, reproduction, and erasure using an output signal from the optical pickup device.

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