JP2003162830A - Optical pickup and optical disc drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup that can correct a displaced optical axis in real time at a low cost without making it large even when operating. <P>SOLUTION: The light flux emitted from the light source 51 is optically divided by an optical divider 60 and received by the second photo acceptance element 61 which is divided into at least two. This second photo acceptance element 61 outputs signals matching the displaced amount in the direction of the emitted light flux from the light source unit 51. The displaced optical axis corrector 73 corrects the displaced optical axis caused by the displaced direction of the emitted light based on the signal matching the displaced amount in the direction of the emitted light flux. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device and an optical disc device, and more particularly, it is used for at least reproduction of recording, reproducing, and erasing of information on an optical recording medium, and recording of an optical recording medium. The present invention relates to an optical pickup device arranged such that its emission end faces a surface, and an optical disc device including the optical pickup device.

[0002]

2. Description of the Related Art In an optical disk device, information is recorded on an optical recording medium such as a CD-R by irradiating a minute spot of laser light on its recording surface, and based on the reflected light from the recording surface. Information is played back. The optical disc device is generally equipped with an optical pickup device for irradiating the recording surface of the optical recording medium with laser light and receiving the reflected light from the recording surface.

Generally, an optical pickup device guides a light source, an optical system for guiding a light beam emitted from the light source to a recording surface of an optical recording medium, and a returning light beam reflected by the recording surface to a predetermined light receiving position, and a light receiving device. It is provided with a light receiving element or the like arranged at a position. They are assembled in the housing of the optical pickup device.

In recent years, the capacity of optical recording media has dramatically increased, and the recording speed has been increased. Accordingly, the optical pickup device can be more quickly and
Moreover, there is an increasing demand for accurately irradiating a minute spot to a predetermined position on the recording surface of an optical recording medium.

For example, the optical axis of a light beam emitted from a light source (hereinafter referred to as "emission optical axis") is the designed optical axis (hereinafter referred to as "optical axis").
If it does not match the "ideal optical axis"), the intensity distribution of the light emitted from the light source differs from the designed intensity distribution in the optical system, so the light intensity distribution becomes asymmetric on the recording surface of the optical recording medium. Therefore, there arises a disadvantage that accurate recording and reproduction cannot be performed. In some cases, wavefront aberration occurs, the spot cannot be fully stopped, and the amount of irradiation light (so-called power) on the recording surface decreases. This is inconvenient especially in the case of a DVD that is recorded at a high density and when performing high-speed writing that requires a large power.

In order to improve this inconvenience, various technological developments have been carried out for assembling the light source and the optical system into the housing of the optical pickup device so as to reduce the difference between the output optical axis and the ideal optical axis, that is, the optical axis shift. I was broken.

For example, in Japanese Unexamined Patent Publication No. 9-219033, a holder used when a semiconductor laser unit as a light source is attached to a housing of an optical pickup device,
A laser holder device capable of adjusting the rotation of the semiconductor laser unit in addition to the two-dimensional position adjustment of the semiconductor laser unit by combining a member having a convex portion and a member having a concave portion is disclosed. As a result, when the semiconductor laser unit is assembled, the position and orientation of the semiconductor laser unit that causes the deviation of the emission optical axis are corrected.

[0008]

However, in Japanese Unexamined Patent Publication No. 9-219033, the structure of the holder itself becomes complicated, and there is a disadvantage that the optical pickup device including the holder becomes large in size and high in cost. It was

In order to improve this inconvenience, Japanese Patent Laid-Open No. 2001-2001
According to Japanese Patent No. 134951, a holder (adapter) having a mounting surface for mounting a semiconductor laser unit and a mounting surface mounted on a housing of an optical pickup device, and capable of adjusting an angle formed between the mounting surface and the mounting surface. An optical pickup device using is disclosed. According to this, the structure of the holder is simplified, and by rotating the holder, the deviation of the emission direction of the laser light from the semiconductor laser unit can be corrected.

However, even if the deviation of the emission direction of the laser beam is accurately corrected during assembly, the emission direction may be gradually shifted due to temperature changes and vibrations during operation. In such a case, readjustment must be performed in a factory or the like, and during that time, the user cannot use the optical disk device, which is a disadvantage. In particular, with respect to an optical recording medium on which high density recording has been performed, a slight deviation in the emission direction has a great influence on the recording and reproducing accuracy, so that stability with time is important.

The present invention has been made under the above circumstances, and a first object thereof is to automatically correct an optical axis deviation in real time at a low cost even during operation without causing an increase in size. An object of the present invention is to provide an optical pickup device that can be used.

A second object of the present invention is to provide an optical disk device capable of reproducing information with high accuracy on an optical recording medium recorded at high density.

[0013]

According to a first aspect of the present invention, the invention is used for at least reproduction of recording, reproducing and erasing of information on an optical recording medium, and the information is recorded on the recording surface of the optical recording medium. An optical pickup device arranged such that emission ends thereof face each other; a light source unit; a light flux emitted from the light source unit, guided to a recording surface of the optical recording medium, and a return light flux reflected by the recording surface. An optical system that guides the light to a predetermined light receiving position; a first light receiving element that is arranged at the light receiving position; a branching optical that is arranged on an optical path of a light beam emitted from the light source unit and optically branches the light beam. A light receiving surface for receiving a light beam branched from the optical path toward the recording surface by the branching optical means and outputting a signal according to the deviation of the emission direction of the light beam emitted from the light source unit. A second light receiving element divided into at least two; and an optical axis deviation correcting means for correcting the optical axis deviation of the light flux due to the deviation of the emission direction based on the signal output from the second light receiving element. Is an optical pickup device.

According to this, the light flux emitted from the light source unit is optically branched by the branch optical means and received by the second light receiving element. Then, the second light receiving element outputs a signal corresponding to the amount of received light for each of the divided areas. Here, since the emission direction of the light beam emitted from the light source unit and the light receiving position of the light beam on the light receiving surface of the second light receiving element have a correlation, the output signal from the second light receiving element includes the light source. The information about the emission direction of the emitted light beam from the unit is included. That is, the second light receiving element outputs a signal according to the deviation of the emission direction of the emitted light beam from the light source unit.

Then, the optical axis shift correcting means corrects the optical axis shift caused by the deviation of the emission direction based on the signal corresponding to the deviation of the emission direction of the emitted light beam from the light source unit. For example, in the case where the second light receiving element is composed of two-divided light receiving elements, the difference between the signals of the respective regions output from the second light receiving element when the emission direction deviation is small enough to be ignored in advance (hereinafter referred to as “ If the difference signal is used as a reference value, the difference signal is calculated based on the output signal from the second light receiving element at the time of measurement, and the difference signal is compared with the reference value to emit the light flux emitted from the light source unit. A direction shift can be detected. Then, the optical axis shift can be corrected by driving the optical element that constitutes the optical system so that the difference signal becomes substantially equal to the reference value. That is, it is possible to correct the optical axis deviation at low cost without requiring a complicated holder as in the conventional case. Further, since the optical axis shift can be automatically corrected, the output direction shift can be constantly monitored during operation, and the optical axis shift can be corrected each time in real time. Therefore, it becomes possible to improve stability and reliability over time. Furthermore, since the deviation of the emission direction is detected by the branch optical means and the second light receiving element, the size of the device does not increase.

In this case, as in the optical pickup device according to the second aspect of the invention, there is provided a light condensing means which is arranged in the vicinity of the light receiving surface of the second light receiving element and which condenses the light beam incident on the light receiving surface. Further provision may be made. Here, the vicinity of the light receiving surface means within a predetermined distance range from the light receiving surface, and includes the case where it is in contact with the light receiving surface. In this case, the size of the light spot on the light receiving surface can be reduced, so that the S / N ratio is increased and the detection accuracy of the deviation in the emission direction can be improved. Further, since the light receiving area of the second light receiving element can be reduced, it is possible to promote the reduction in size and weight of the optical pickup device.

In each of the optical pickup devices described in claims 1 and 2, as in the optical pickup device described in claim 3, the branching optical means deflects at least a part of the peripheral portion of the light beam to form the light beam. It may be a deflecting element that leads to the light receiving surface of the second light receiving element. Here, at least a part of the peripheral portion is a concept including the entire area of the peripheral portion and the entire surface of the light flux. In such a case, since a deflecting element that deflects at least a part of the peripheral part of the light beam is used as the branching optical means, a part of the light beam emitted from the light source unit is not affected by the arrangement of the optical system. Can be guided to the light receiving surface of the second light receiving element. Therefore, it is possible to detect the deviation of the emission direction at low cost, and it is possible to promote miniaturization of the optical pickup device.

In this case, as in the optical pickup device according to the fourth aspect, the deflection element may be integrated with another optical element forming the optical system. In this case, since the deflecting element is integrated with other optical elements constituting the optical system, it is possible to detect the deviation of the emission direction at a lower cost and to reduce the size and weight of the optical pickup device. Can be promoted.

In each of the optical pickup devices described in claims 1 to 4, as in the optical pickup device described in claim 5, the signal output from the second light receiving element is output from the light emitted from the light source unit. It is possible to further include conversion means for converting the signal into a signal according to the intensity. In such a case, the conversion unit can add a signal for each area output from the second light receiving element to obtain a signal corresponding to the intensity of the light emitted from the light source unit. It is not necessary to separately provide a light receiving element for monitoring the intensity of the emitted light of the. Therefore, it is possible to promote cost reduction and size and weight reduction of the optical pickup device.

In each of the optical pickup devices described in claims 1 to 5, as in the optical pickup device described in claim 6, at least the second light receiving element of the first and second light receiving elements is It may be housed in the same housing as the light source unit and packaged.
In such a case, of the first and second light receiving elements, at least the second light receiving element is housed and packaged in the same housing as the light source unit, which further reduces the size of the optical pickup device. Can be promoted.

The invention according to claim 7 is an optical disk device for recording, reproducing, and erasing at least information on an optical disk, and the optical pickup device according to claim 1; An optical disc device comprising: a processing device for performing at least reproduction of recording, reproduction and erasing of the information by using an output signal of the first light receiving element which constitutes the optical pickup device.

According to this, since the optical pickup device according to any one of claims 1 to 5 is provided, the deviation of the emission direction of the emitted light beam from the light source unit is constantly monitored, and the light beam caused by the deviation of the emission direction is real-time. The optical axis shift of can be corrected. Therefore, even for an optical disc on which information is recorded at a high density such as a DVD, it is possible to always irradiate a fine spot at a predetermined position on the recording surface of the optical disc with accuracy. That is, it is possible to accurately reproduce information even on an optical recording medium on which high density recording is performed.

According to an eighth aspect of the present invention, there is provided an optical disk device for performing at least reproduction of information recording, reproduction, and erasing on the optical disk, wherein the first and second light receiving elements are the light source. The optical pickup device according to claim 6, which is housed and packaged in the same housing as the unit; and is obtained from the output of the first light receiving element based on the signal output from the second light receiving element. Correcting means for correcting the track error signal that is recorded; recording and reproducing of the information by using the output signal of the first light receiving element;
And an erasing processing unit for performing at least reproduction.

According to this, in the optical pickup device,
The first and second light receiving elements are housed and packaged in the same housing as the light source unit. In this case, in order to correct the deviation in the emission direction of the light flux emitted from the light source unit, for example, when an optical element forming the optical system of the optical pickup device is driven, a track error obtained from the output signal of the first light receiving element An offset due to the correction of the deviation in the emission direction is added to the signal. That is, erroneous tracking servo may be performed. Therefore, when the correlation between the deviation of the emitting direction and the offset is obtained in advance and the deviation of the emitting direction is corrected, the correcting means responds to the deviation of the emitting direction based on the output signal from the second light receiving element. The offset is obtained from the correlation, and the output signal of the first light receiving element is corrected by the obtained offset. Therefore, tracking servo can be performed with high accuracy, and as a result, information can be reproduced with high accuracy even on an optical recording medium on which high density recording is performed.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION << First Embodiment >> A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a schematic structure of an optical disk device 20 according to the first embodiment.

The optical disk device 20 shown in FIG.
Is a spindle motor 22 for rotating the optical disk 15, an optical pickup 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 R.
An AM 34, a buffer manager 37, an interface 38, a ROM 39, a CPU 40, a RAM 41 and the like are provided. It should be noted that the arrows in FIG. 1 show typical flows of signals and information, and do not show all the connection relations of each block.

As shown in FIG. 2A, the optical pickup 23 includes a semiconductor laser unit 51 as a light source unit, a collimator lens 52, and a reflection mirror 5.
3, first polarization beam splitter 54, λ / 4 plate 55,
An optical system such as a deflection prism 56, an objective lens 57, a first condenser lens 58, a first light receiver 59, a half mirror 60 as a branch optical unit, a second light receiver 61, and a beam shaping prism (not shown). And an optical axis control circuit 73 as an optical axis deviation correcting means, and a drive system (reflection mirror drive system, deflection prism drive system, focusing actuator, tracking actuator, seek motor, etc.) (all not shown). Has been done. Note that FIG.
LR in (A) indicates the ideal optical axis of the light flux emitted from the semiconductor laser unit 51.

The first light receiver 59 receives the reflected light from the recording surface of the optical disc and includes wobble signal information, reproduction data information, focus error information, track error information, etc., as in the conventional optical pickup. Output a signal.

The second light receiver 61 is, for example, as shown in FIG.
As shown in (B), the light-receiving surface is divided into two parts in the X-axis direction and the Y-axis direction, respectively, into four-divided light-receiving elements (first divided light-receiving element 61a, second divided light-receiving element 61b, and third divided light-receiving element 61b. It is configured to include a divided light receiving element 61c and a fourth divided light receiving element 61d). And from each divided light receiving element,
A current (current signal) corresponding to the amount of received light is output to the optical axis control circuit 73, respectively. The second
The light receiver 61 is arranged at a position corresponding to the ideal optical axis. That is, when the optical axis shift is small, the light receiving amounts of the respective divided light receiving elements are substantially equal.

As shown in FIG. 3, the semiconductor laser unit 51 includes a semiconductor laser chip 51a that emits laser light, a stem 51b that holds the semiconductor laser chip 51a, and laser light emitted from the semiconductor laser chip 51a to the outside. Opening part (hereinafter referred to as "exit window")
Cover 51 for protecting the semiconductor laser chip 51a
It is configured including c and the like.

The reflection mirror drive system is composed of an optical axis control circuit 7
3 based on the reflection mirror drive signal from the reflection mirror 53.
Is configured to include a motor, a piezoelectric element, and the like (not shown) for shifting in the X-axis direction.

The deflecting prism driving system includes a motor (not shown) and a piezoelectric element (not shown) for shifting the deflecting prism 56 in the Y-axis direction based on the deflecting prism driving signal from the optical axis control circuit 73. .

Returning to FIG. 2A, the light beam of linearly polarized light (polarized light (P-polarized light) parallel to the incident surface of the first polarization beam splitter described later) emitted from the semiconductor laser unit 51 is collimated by the collimator lens 52. The light beam is made into substantially parallel light, its optical axis is bent in the -X direction by the reflection mirror 53, is branched in two directions by the half mirror 60, and one light beam transmitted through the half mirror 60 is the first polarization beam splitter 54.
Is incident on. The light flux transmitted through the first polarization beam splitter 54 is circularly polarized by the λ / 4 plate 55, its optical axis is bent in the + Y direction by the deflection prism 56, and the optical disc 15 is recorded through the objective lens 57. It is focused on the surface as a minute spot.

The reflected light reflected by the recording surface of the optical disk 15 becomes circularly polarized light in the opposite direction to the outward path, and the objective lens 5
In 7 again, the light is made into substantially parallel light, is deflected in the + X direction by the deflecting prism 56, and is converted into linearly polarized light (S polarized light) orthogonal to the outward path by the λ / 4 plate 55. Then, the reflected light is deflected in the −Z direction by the first polarization beam splitter 54,
The light is received by the first light receiver 59 via the condensing lens 58. A current (current signal) corresponding to the amount of received light is output from the first light receiver 59 to the reproduction signal processing circuit 28.

The other light flux reflected by the half mirror 60 and branched in the -Z direction is received by the second light receiver 61. Then, the divided light receiving elements 61a to 61d output current signals corresponding to the respective light receiving amounts to the optical axis control circuit 73.

Returning to FIG. 1, in the reproduction signal processing circuit 28,
A current signal which is an output signal of the optical pickup 23 is converted into a voltage signal, and a wobble signal, an RF signal including reproduction information and a servo signal (focus error signal, track error signal, etc.) are detected based on the voltage signal. And
In the reproduction signal processing circuit 28, the ATIP is changed from the wobble signal.
(Absolute Time In Pre-groove) Information and sync signals are extracted. The ATIP information extracted here is the CPU 4
0, and the sync signal is output to the encoder 25. Further, the reproduction signal processing circuit 28 performs error correction processing and the like on the RF signal, and then stores it in the buffer RAM 34 via the buffer manager 37. The focus error signal and the track error signal are output from the reproduction signal processing circuit 28 to the servo controller 33.

The servo controller 33 generates a control signal for controlling the focusing actuator of the optical pickup 23 based on the focus error signal,
A control signal for controlling the tracking actuator of the optical pickup 23 is generated based on the track error signal. Both control signals are output from the servo controller 33 to the motor driver 27.

The buffer manager 37 manages the accumulation of data in the buffer RAM 34 and notifies the CPU 40 when the accumulated data amount reaches a predetermined value.

The motor driver 27 drives the focusing actuator and the tracking actuator of the optical pickup 23 based on the control signal from the servo controller 33. Also, the motor driver 2
7, the optical disk 15 is operated based on the instruction of the CPU 40.
The spindle motor 22 is controlled so that the linear velocity is constant. Further, in the motor driver 27, the CPU 40
Based on the instruction, the seek motor of the optical pickup 23 is driven to control the position of the optical pickup 23 in the sledge direction (radial direction of the optical disc 15).

In the encoder 25, based on an instruction from the CPU 40, the data stored in the buffer RAM 34 is taken out via the buffer manager 37, an error correction code is added, etc., and write data to the optical disk 15 is created. . Then, the encoder 25 outputs the write data to the laser control circuit 24 in synchronization with the synchronization signal from the reproduction signal processing circuit 28 based on the instruction from the CPU 40.

The laser control circuit 24 controls the output of the semiconductor laser chip 51a of the optical pickup 23 based on the write data from the encoder 25.

The interface 38 is a bidirectional communication interface with a host (for example, a personal computer), and is an ATAPI (AT Attachment Pack).
et Interface) and SCSI (Small Computer System)
Interface) and other standard interfaces.

The ROM 39 stores a program written in a code readable by the CPU 40.

The CPU 40 controls the operation of each of the above parts according to the program stored in the ROM 39, and temporarily stores the data and the like required for the control in the RAM 41.

Next, the detection of deviation of the luminous flux emitted from the semiconductor laser unit 51 in the emission direction will be described.

When the difference between the emission direction of the emitted light beam from the semiconductor laser unit 51 (hereinafter referred to as "emission direction") and the designed emission direction (hereinafter referred to as "emission direction shift") is small, As shown in FIG. 4A, the optical axis of the light beam emitted from the semiconductor laser unit 51 (hereinafter, abbreviated as “emission optical axis”) substantially coincides with the ideal optical axis, and the half mirror 60 The reflected light flux (referred to as LB) is shown in FIG.
As shown in (B), the light is incident on the central portion of the second light receiver 61. In this case, the output signal from the first divided light receiving element 61a (denoted by signal Sa), the output signal from the second divided light receiving element 61b (denoted by signal Sb), and the output signal from the third divided light receiving element 61c. Output signal (Signal Sc)
And an output signal from the fourth divided light receiving element 61d (signal S
d) are almost equal to each other.

On the other hand, as shown in FIG. 4C, when the emission direction is shifted in the -X direction, the emission optical axis does not coincide with the ideal optical axis LR and is reflected by the half mirror 60. As shown in FIG. 4D, the light beam LB is shifted in the + X direction and is incident on the second light receiver 61 as compared with the case where the emission direction is not displaced. In this case, (signal Sb + signal Sd) becomes smaller than (signal Sa + signal Sc).

Further, as shown in FIG. 5A, when the emitting direction is deviated to the + X direction, the emitting optical axis does not coincide with the ideal optical axis LR and is reflected by the half mirror 60. As shown in FIG. 5B, the light flux LB is shifted in the −X direction and is incident on the second light receiver 61 as compared with the case where the outgoing optical axis is not displaced. In this case, (signal Sb + signal Sd) becomes larger than (signal Sa + signal Sc).
Note that only a part of the optical pickup 23 is illustrated in FIGS. 4A, 4B, and 5A.

That is, the deviation of the emission direction with respect to the X direction can be detected by the difference between the (signal Sb + signal Sd) and the (signal Sa + signal Sc) (hereinafter referred to as “first difference signal”). Further, as shown in FIG. 6A as an example, if the correlation between the first difference signal and the deviation amount (angle) in the emission direction with respect to the X direction is obtained in advance, measurement is performed based on the correlation. The emission direction deviation can be quantitatively obtained from the first difference signal at the time.

Therefore, the optical axis control circuit 73 calculates the first difference signal ΔSx based on the following equation (1).

ΔSx = (Sb + Sd)-(Sa + Sc) (1)

Then, the optical axis control circuit 73 refers to the correlation between ΔSx that has been experimentally obtained in advance and the deviation of the emission direction with respect to the X direction, and the X corresponding to the calculated ΔSx.
The emission direction shift with respect to the direction is obtained.

Similarly to the above, the deviation of the emission direction with respect to the Y direction is (signal Sa + signal Sb) and (signal Sc + signal S).
It can be detected from the difference from d) (hereinafter referred to as “second difference signal”).

Therefore, the optical axis control circuit 73 uses the following (2)
The second difference signal ΔSy is calculated based on the equation.

ΔSy = (Sa + Sb)-(Sc + Sd) (2)

Then, the optical axis control circuit 73, as shown in FIG. 6B as an example, has a predetermined ΔS.
By referring to the correlation between y and the emission direction deviation in the Y direction, the emission direction deviation in the Y direction corresponding to the calculated ΔSy is obtained.

Further, the optical axis control circuit 73 generates a reflection mirror drive signal for correcting the deviation of the emission direction in the X direction obtained as described above, based on the deviation. Then, it outputs to the reflection mirror drive system.

For example, as shown in FIG. 7A, when the emission direction is shifted in the -X direction, the reflection mirror 53
Is shifted in the -X direction, and the optical axis of the light flux bent by the reflection mirror 53 is made substantially coincident with the ideal optical axis. On the other hand, for example, as shown in FIG. 7B, when the outgoing optical axis is deviated in the + X direction, the reflection mirror 53 is shifted in the + X direction and the optical axis of the light flux bent by the reflection mirror 53 is changed. Match the ideal optical axis.

Further, the optical axis control circuit 73 generates a deflection prism drive signal for correcting the deviation of the emission direction in the Y direction obtained as described above, based on the deviation. Then, it outputs to the deflection prism drive system.

For example, as shown in FIG. 7C, when the emission direction is shifted in the + Y direction, the deflection prism 5
6 is shifted in the + Y direction so that the optical axis of the light beam bent by the deflecting prism 56 substantially coincides with the ideal optical axis. on the other hand,
For example, as shown in FIG. 7D, when the outgoing optical axis is deviated in the −Y direction, the deflection prism 56 is shifted in the −Y direction, and the optical axis of the light beam bent by the deflection prism 56 is changed. Match the ideal optical axis.

Further, the optical axis control circuit 73 adds the output signals of the respective light receiving elements and outputs a signal according to the intensity of the light emitted from the semiconductor laser unit 51 to the CPU 40. This signal is used to control the laser control circuit 24.

The optical axis control circuit 73 always monitors the deviation of the emission direction, and upon detecting the deviation, immediately corrects the deviation via the reflection mirror drive system and the deflection prism drive system as described above. .

Next, the processing operation when data is recorded on the optical disk 15 using the optical disk device 20 configured as described above will be briefly described.

When the CPU 40 receives the recording request from the host, it instructs the reproduction signal processing circuit 28 to acquire ATIP information and also instructs the motor driver 27 to rotate the spindle motor 22 at a predetermined linear velocity. When the rotation of the optical disk 15 reaches a predetermined linear velocity, the optical axis control circuit 73 of the optical pickup 23 detects the emission direction as described above, and if there is a deviation in the emission direction, it is passed through the reflection mirror drive system and the deflection prism drive system. Correct the deviation.
Then, in the optical pickup 23, the reflected light from the recording surface of the optical disk 15 is received by the first light receiver 59 and is output to the reproduction signal processing circuit 28. The reproduction signal processing circuit 28 is
The ATIP information is extracted from the output signal of the first light receiver 59 and notified to the CPU 40.

When the CPU 40 receives the data from the host, the CPU 40 passes the buffer RAM through the buffer manager 37.
34. When the amount of data accumulated in the buffer RAM 34 exceeds a predetermined value, the buffer manager 37
Notifies the CPU 40.

Upon receiving the notification from the buffer manager 37, the CPU 40 instructs the encoder 25 to create write data. Then, the CPU 40 uses ATIP
Based on the information, a signal for instructing the seek operation of the optical pickup 23 so that the optical pickup 23 is located at a predetermined writing start point is output to the motor driver 27.

The CPU 40, based on the ATIP information,
When it is determined that the position of the optical pickup 23 is the writing start point, the encoder 25 is notified. Then, the encoder 25 records the write data on the optical disk 15 via the laser control circuit 24 and the optical pickup 23.

Next, the processing operation when the data recorded on the optical disk 15 is reproduced by using the above-mentioned optical disk device 20 will be briefly described.

Upon receiving the reproduction request from the host, the CPU 40 instructs the reproduction signal processing circuit 28 to acquire ATIP information and also instructs the motor driver 27 to rotate the spindle motor 22 at a predetermined linear velocity. When the rotation of the optical disk 15 reaches a predetermined linear velocity, the optical axis control circuit 73 of the optical pickup 23 detects the emission direction as described above, and if there is a deviation in the emission direction, it is passed through the reflection mirror drive system and the deflection prism drive system. Correct the deviation.
Then, in the optical pickup 23, the reflected light from the recording surface of the optical disk 15 is received by the first light receiver 59 and is output to the reproduction signal processing circuit 28. The reproduction signal processing circuit 28 is
The ATIP information is extracted from the output signal of the first light receiver 59 and notified to the CPU 40.

Then, the CPU 40 sets the optical pickup 23 at a predetermined reading start point based on the ATIP information.
A signal for instructing the seek operation of the optical pickup 23 to output the position is output to the motor driver 27.

The CPU 40, based on the ATIP information,
Check whether it is the reading start point. When it is determined that the position of the optical pickup 23 is the reading start point, the reproduction signal processing circuit 28 is notified.

In the reproduction signal processing circuit 28, the RF signal is detected based on the output signal of the first photodetector 59, subjected to error correction processing and the like, and then stored in the buffer RAM 34.

The buffer manager 37 uses the buffer RA
When the data accumulated in M34 is prepared as sector data, it is transferred to the host via the interface 38.

As is apparent from the above description, in the optical pickup device according to the first embodiment, the optical axis control circuit 73 constitutes the conversion means.

Further, in the optical disk device according to the first embodiment, the CPU 40 constitutes a processing device.

As described above, in the optical pickup device according to the first embodiment, the semiconductor laser unit 5 is used.
The light flux emitted from the first mirror 2 is transmitted through the half mirror 60 to the second mirror.
The divided light receiving elements of the light receiver 61 receive light, and the optical axis control circuit 73 detects the deviation of the emitting direction based on the output signal from each divided light receiving element. Then, based on the detected deviation of the emission direction, the reflection mirror 53 and the deflection prism 56.
To correct the optical axis shift due to the deviation of the emission direction. Therefore, the structure of the holder used when the semiconductor laser unit 51 is attached to the housing can be simplified as compared with the conventional one, and the optical axis deviation can be automatically corrected. That is, it is possible to automatically correct the optical axis deviation in real time at a lower cost than before.

Further, in the first embodiment, the deviation of the emission direction is constantly monitored even during operation, and if the deviation of the emission direction is detected, the deviation of the optical axis can be corrected in real time. It is possible to improve reliability and reliability.

Further, in the optical disc apparatus according to the first embodiment, since the optical axis shift of the light beam emitted from the optical pickup 23 to the optical disc 15 is automatically corrected in real time, the optical recording medium recorded with high density is recorded. Against
It is possible to reproduce information with high accuracy.

In the first embodiment described above, a four-divided photodetector is used as the second photodetector 61. However, when detecting only the deviation of the emission direction in the X direction, the second photodetector 61 is used. Instead of this, a two-divided light receiving element that is divided into two in the X-axis direction may be used. Similarly, when only the emission direction deviation in the Y direction is obtained, a two-divided light receiving element that is divided into two in the Y axis direction may be used instead of the second light receiver 61.

In addition, in the first embodiment, the half mirror 60 is arranged at the rear stage of the reflection mirror 53.
However, the present invention is not limited to this, and may be arranged, for example, before the reflection mirror 53. In this case, of course, the arrangement position of the second light receiver 61 is also changed accordingly.

In the first embodiment, as shown in FIG. 8A as an example, the second light receiver 61 is used.
A second condenser lens 62 as a condenser may be added on the light receiving surface of the. As shown in FIG. 8B, the second condenser lens 62 reflects the light flux reflected by the half mirror 60 at a point F behind the second light receiver 61 (−Z direction).
It is set so as to collect light on P. As a result, as shown in FIG. 8C, the size of the light spot formed on the second light receiver 61 is smaller than that in the case without the second condenser lens 62 (SP1). When the second condenser lens 62 is present (SP2), the size is smaller, and the light receiving area of the second light receiver 61 can be smaller. In this case, the S / N ratio becomes large, and the detection accuracy of the deviation in the emission direction can be improved. Here, the second condenser lens 62 does not necessarily have to be in contact with the light receiving surface of the second light receiver 61. In short, it suffices that the light beam reflected by the half mirror 60 can be condensed on the light receiving surface of the second light receiver 61 as a light spot of a predetermined size.

In the first embodiment, the half mirror 60 is used to deflect a part of the luminous flux emitted from the semiconductor laser unit 51. However, the function of the half mirror 60 is added to other optical elements. You may let me.

For example, as shown in FIG. 9A as an example, instead of the first polarization beam splitter 54, a part of the light beam reflected by the reflection mirror 53 is branched in a predetermined direction. The designed second polarization beam splitter 67 may be used. Here, the light flux reflected by the reflection mirror 53 is partially deflected in the + Z direction by the second polarization beam splitter 67. Of course, the second light receiver 61 is arranged at a position where it can receive the light deflected by the second polarization beam splitter 67.

As an example, as shown in FIG. 9B, a beam shaping prism 69 in which a half mirror 60 and a beam shaping prism are integrated may be used. Here, the beam shaping prism 69 is arranged in the latter stage of the reflection mirror 53, and deflects a part of the light beam bent by the reflection mirror 53. Of course, the second light receiver 61 is arranged at a position where the light deflected by the beam shaping prism 69 can be received.

That is, like the above-mentioned second polarization beam splitter 67 and beam shaping prism 69, an optical element that makes the light beam emitted from the semiconductor laser unit 51 into the incident light beam is part of the incident light beam in a predetermined direction. By adding the deflecting function of deflecting, it is possible to reduce the size and cost of the optical pickup 23.

<< Second Embodiment >> A second embodiment of the present invention will be described below with reference to FIGS.

In the second embodiment, only a part of the optical pickup 23 in the first embodiment is changed, and other parts are the same as those in the first embodiment. Therefore, the same reference numerals will be used for the same or similar components as in the first embodiment described above, and the differences from the first embodiment will be mainly described.

In the second embodiment, as shown in FIG. 10A, the optical pickup 2 of the first embodiment described above is used.
A transmissive optical diffraction element 63 is arranged instead of the half mirror 60 in FIG. Therefore, the second light receiver 6
1 is arranged at a position different from that of the first embodiment.

In this embodiment, the light diffractive element 63 has a Y-axis direction and a Z-axis as shown in FIG. 10B as an example.
Each is divided into two in the axial direction, that is, as a whole divided into four (first diffraction element 63a, second diffraction element 63b, third diffraction element 63b,
Diffractive element 63c and fourth diffractive element 63d).

Now, the detection of the deviation of the luminous flux emitted from the semiconductor laser unit 51 in the emission direction will be described.

The light beam emitted from the semiconductor laser unit 51 is made into substantially parallel light by the collimator lens 52 and is incident on the light diffraction element 63. This optical diffraction element 63
A part of the light beam incident on is a diffracted light, which is received by the light receiving surface of the second light receiver 61. Here, the diffracted light from the first diffractive element 63a is the first split light receiving element 61a, the diffracted light from the second diffractive element 63b is the second split light receiving element 61b, and the third diffractive element 63c. The diffracted light of is received by the third divided light receiving element 61c, and the diffracted light from the fourth diffracted element 63d is received by the fourth divided light receiving element 61d.

When the deviation of the emission direction is small, the result shown in FIG.
As shown in FIG. 11A, the emission optical axis is substantially coincident with the ideal optical axis LR, and the light flux (LM) reflected by the reflection mirror 53 is as shown in FIG. ,
The light is incident on the central portion of the light diffraction element 63. Then, the diffracted light (denoted by LK) diffracted by the light diffraction element 63 is incident on the central portion of the second light receiver 61 as shown in FIG. 11C as an example. In this case, the output signals from the respective divided light receiving elements are almost equal to each other.

On the other hand, as shown in FIG. 12A as an example, when the emission direction is deviated to the −X direction, the emission optical axis does not coincide with the ideal optical axis LR, and the reflection mirror 53 causes The reflected light flux LM is + Z as compared with the case where the emission direction is not displaced, as shown in FIG. 12B as an example.
The light is shifted in the direction and is incident on the optical diffraction element 63. The diffracted light LK diffracted by the light diffraction element 63 is shifted in the + Z direction as compared with the case where the emission direction is not shifted, as shown in FIG. It is incident on 61. In this case, (signal Sb + signal S
d) becomes larger than (signal Sa + signal Sc). Note that FIG. 11A and FIG. 12A show only a part of the optical pickup 23.

When the emission direction is displaced in the + X direction, the emission optical axis does not coincide with the ideal optical axis LR, and the light beam LM reflected by the reflection mirror 53 is not displaced in the emission direction. The optical diffraction element 63 shifts in the -Z direction compared to
Is incident on. Then, the diffracted light LK diffracted by the light diffractive element 63 is −
The light is shifted in the Z direction and is incident on the second light receiver 61. In this case, (signal Sb + signal Sd) is (signal Sa + signal S
It is smaller than in c).

That is, similarly to the first embodiment, in the optical axis control circuit 73, the deviation of the emission direction in the X direction is based on the first difference signal Sx, and the emission direction in the Y direction is based on the second difference signal Sy. Each deviation can be detected.

Then, the optical axis control circuit 73 drives the reflection mirror 53 and the deflection prism 56 in the same manner as in the first embodiment, and corrects the optical axis shift caused by the deviation of the emission direction.

The processing for recording data on the optical disk 15 and the processing for reproducing the data recorded on the optical disk 15 are performed in the same manner as in the first embodiment.

As described above, in the optical pickup device according to the second embodiment, the semiconductor laser unit 5 is used.
The light beam emitted from the first light is diffracted by the light diffraction element 63, and the diffracted light is received by the second light receiver 61, and the second light receiver 6
The deviation of the emission direction is detected by the optical axis control circuit 73 based on the output signal from 1. Then, based on the detected deviation of the emission direction, the reflection mirror 53 and the deflection prism 56.
To correct the optical axis shift due to the deviation of the emission direction. Therefore, the structure of the holder used when the semiconductor laser unit 51 is attached to the housing can be made simpler than before, and the optical axis deviation can be automatically corrected. That is, it is possible to automatically correct the optical axis deviation in real time at a lower cost than in the past.

Further, in the second embodiment, the spot of the diffracted light on the light receiving surface of the second light receiver 61 can be narrowed down by the light diffraction element 63. The second without the condenser lens 62
It is possible to reduce the light receiving area of the light receiver 61 of
By improving the N ratio, it is possible to improve the detection accuracy of the deviation in the emission direction.

Further, in the optical disk device according to the second embodiment, the optical axis shift of the light beam emitted from the optical pickup 23 to the optical disk 15 is automatically corrected in real time, as in the first embodiment. In addition, it is possible to accurately reproduce information even on an optical recording medium on which high density recording is performed.

Although the transmission type light diffractive element 63 is used in the second embodiment, a reflection type light diffractive element may be used. In this case, of course, the arrangement position of the second light receiver 61 is also changed accordingly.

In the second embodiment, the four-division diffractive element is used as the light diffractive element 63. However, when only the emission direction deviation in the X direction is obtained, the Z-axis is used instead of the light diffractive element 63. A two-divided diffraction element that is divided in two in the direction may be used instead of the second light-receiving device 61, and a two-divided light-receiving element that is divided in two in the Z-axis direction may be used. Similarly, Y
In the case of obtaining only the deviation of the emission direction with respect to the direction, a two-divided diffraction element which is divided in two in the Y-axis direction is used instead of the light diffraction element 63, and two-divided in the Y-axis direction instead of the second light receiver 61. Two-divided light receiving elements may be used respectively.

Further, in the second embodiment described above, the light diffraction element 63 is arranged at the rear stage of the reflection mirror 53,
The present invention is not limited to this, and may be arranged, for example, before the reflection mirror 53. In this case, of course, the arrangement position of the second light receiver 61 is also changed accordingly.

Further, in the second embodiment, the light diffraction element 63 generates diffracted light based on all the light fluxes bent by the reflection mirror 53, but the invention is not limited to this. For example, the diffracted light may be generated based on a part of the light flux in the peripheral portion of the light flux bent by the reflection mirror 53.

Therefore, instead of the optical diffractive element 63, as shown in FIG.
As shown in FIG. 3A, the case where the transmission type partial light diffraction element 65 in which the diffraction grating pattern is formed only on the outer peripheral portion is used will be briefly described.

When the deviation in the emission direction is small, the result shown in FIG.
As shown in (B), the emission optical axis substantially matches the ideal optical axis LR, and the light flux LM reflected by the reflection mirror 53 is
As an example, as shown in FIG. 13C, the light is incident on the central portion of the partial light diffraction element 65. Then, the diffracted light LK ′ diffracted at the outer peripheral portion of the partial light diffraction element 65 is
The light is received by the light receiver 61. As an example, as shown in FIG. 13D, the shape of the diffracted light LK ′ on the light receiving surface of the second light receiver 61 is different from that of the light diffractive element 63.
Similar to the case of the light diffraction element 63, the amount of light received by each divided light receiving element of the second light receiver 61 becomes equal. That is, the output signals from the respective divided light receiving elements are almost equal to each other.

On the other hand, as shown in FIG. 14A as an example, when the emission direction is deviated to the −X direction, the emission optical axis does not coincide with the ideal optical axis LR, and the reflection mirror 53 causes The reflected light flux LM is + Z as compared with the case where the emission direction is not displaced, as shown in FIG. 14B as an example.
The light is shifted to the side and enters the partial light diffraction element 65. Then, the diffracted light LK ′ diffracted by the outer peripheral portion of the partial light diffraction element 65 is received by the second light receiver 61. As an example, as shown in FIG. 14C, the shape of the diffracted light LK ′ on the light receiving surface of the second light receiver 61 is different from that of the light diffraction element 63, but like the case of the light diffraction element 63, (Signal Sb + Signal Sd) becomes larger than (Signal Sa + Signal Sc). Note that FIG. 13B and FIG.
Only part of the optical pickup 23 is shown.

When the emission direction is displaced in the + X direction, the emission optical axis does not coincide with the ideal optical axis LR, and the light flux LM reflected by the reflection mirror 53 is not displaced in the emission direction. Compared with, the partial light diffraction element 6 is shifted to the −Z side.
It is incident on 5. Then, the diffracted light LK ′ diffracted by the outer peripheral portion of the partial light diffraction element 65 is received by the second light receiver 61. Diffracted light L on the light receiving surface of the second light receiver 61
Although the shape of K ′ is different from that of the optical diffraction element 63, (signal Sb + signal Sd) is smaller than (signal Sa + signal Sc) as in the case of the optical diffraction element 63.

As described above, even when the partial light diffraction element 65 is used, it is possible to detect the deviation in the emission direction from the output signal of the second photodetector 61, as in the case of the light diffraction element 63. is there. In this case, a reduction in the amount of transmitted light can be suppressed more than in the case of the light diffraction element 63. Also in this case, a reflection type partial light diffraction element may be used, and the arrangement position is not limited to the latter stage of the reflection mirror 53.

In each of the above embodiments, the reflecting mirror 5
Although the driving direction of 3 is the X-axis direction, it may be driven in the Z-axis direction. Further, although the deflection prism 56 is driven in the Y-axis direction, the driving direction is not limited to this, and the deflection prism 56 may be driven in the X-axis direction.

Further, as shown in FIG. 15A as an example, a branching optical element 76 for deflecting the outgoing light flux (corresponding to the half mirror 60 in the first embodiment, and a light diffraction element in the second embodiment). (Corresponding to 63) is arranged at a position in close contact with the emission window of the housing of the semiconductor laser unit 51, and
The light receiver 61 may be housed in the housing of the semiconductor laser unit 51 and packaged. Thereby, the miniaturization of the optical pickup 23 can be promoted. If the second light receiving element 61 can receive a part of the emitted light beam, the branching optical element 76 does not have to be in close contact with the emission window.

Further, as shown in FIG. 15B as an example, the first photodetector 59 together with the second photodetector 61.
May be housed in the housing of the semiconductor laser unit 51 and packaged. In this case, instead of the first polarization beam splitter 54, a transmissive reflected light diffraction element 75 is used.
However, as shown in FIG. 15B as an example, it is arranged at a position in close contact with the branch optical element 76. This allows
The miniaturization of the optical pickup 23 can be further promoted.

As described above, in the optical disk device using the optical pickup 23 having the semiconductor laser unit 51 in which the first light receiver 59 and the second light receiver 61 are housed in the same housing, as described above. Then, the optical axis control circuit 73 detects the deviation of the emitting direction, drives the reflecting mirror 53 or the deflection prism 56, and corrects the optical axis deviation caused by the deviation of the emitting direction. This makes it possible to correct the deviation of the optical axis of the light beam applied to the recording surface of the optical disc 15. However, the reflected light from the recording surface of the optical disk 15 is applied to the first light receiver 59 via the same optical path as the outward path. Therefore, for example, even when the light spot is applied to the correct position on the recording surface, the reflected light is
The central portion of the light receiver 59 of the above is not irradiated. That is, the first
A deviation occurs in the light receiving position of the light receiver 59. The reproduction signal processing circuit 28 (correction means) detects the track error signal based on the output signal of the first light receiver 59.
Due to the deviation of the light receiving position of the first light receiver 59, an erroneous track error signal is detected, and as a result, erroneous tracking servo is performed. The deviation of the light receiving position in the first light receiver 59 has a correlation with the deviation in the emission direction, and the output signal of the first light receiver 59 is a signal to which an offset due to the deviation in the emission direction is added. Therefore, when the correlation between the deviation of the emission direction and the offset is obtained in advance and the deviation of the emission optical axis is corrected, the reproduction signal processing circuit 28
Then, the emission direction deviation is obtained based on the output signal from the second light receiving element 61, the offset corresponding to the emission direction deviation is obtained from the correlation, and the output of the first light receiving element 59 is obtained by the obtained offset. The signal is corrected to detect the track error signal. Then, the corrected track error signal is output to the servo controller 33. This makes it possible to perform tracking servo with high accuracy. If the first light receiving element 59 can receive the reflected light, the reflected light diffraction element 75 does not have to be in close contact with the branch optical element 76. Further, in FIG. 15B, the branched optical element 76 is in close contact with the exit window, and the reflected light diffractive element 75 is arranged on the branched optical element 76. On the contrary, the reflected light diffractive element 75 is arranged. May be brought into close contact with the exit window, and the branch optical element 76 may be disposed thereon.

As is clear from the above description, in the above-mentioned optical pickup device, the reproduction signal processing circuit 28 constitutes the correction means.

Further, the branch optical element 76 and the reflected light diffraction element 75 may be integrated. For example, as shown in FIG. 15C, a branch optical element 76 ′ having the same function as the branch optical element 76 is formed on one surface of the transparent substrate 81, and reflected light diffraction is performed on the other surface. A reflected light diffraction element 75 ′ having the same function as that of the element 75 may be formed, and as shown in FIG. 15D, a branching optical element 76 ′ and a branching optical element 76 ′ are formed on one surface of the transparent substrate 81. Reflected light diffraction element 7
It may be formed by overlapping with 5 '. Furthermore, the branch optical element 7
When 6 is a diffraction grating that diffracts a part of the outgoing light flux,
As shown in FIGS. 15E and 15F, the branching optical element 76 'and the reflected light diffraction element 75' may not be overlapped with each other.

In each of the above-described embodiments, the case where the deviation of the emitting direction is obtained from the first difference signal and the second difference signal and the reflecting mirror 53 and the deflecting prism 56 are driven based on the deviation of the emitting direction is described. However, the relationship between the first difference signal and the drive signal of the reflection mirror 53 and the relationship between the second difference signal and the drive signal of the deflection prism 56 are obtained in advance, and based on the first difference signal and the second difference signal. , Direct reflection mirror 5
3 and the deflection prism 56 may be driven.

In each of the above embodiments, the reflecting mirror 5
Although the description has been given of the case where the optical axis shift is corrected by driving 3 and the deflection prism 56, the optical axis shift may be corrected by using a parallel plate. In this case, a parallel plate is arranged on the optical path, and the optical axis is shifted by adjusting the inclination of the parallel plate with respect to the optical axis.

[0119]

As described above, according to the optical pickup device of the present invention, it is possible to automatically correct the optical axis deviation in real time at a low cost even during operation without causing an increase in size. The effect is that you can do it.

Further, according to the optical disk device of the present invention, there is an effect that information can be reproduced with high precision on an optical recording medium recorded at high density.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an optical disc device according to a first embodiment of the present invention.

FIG. 2A is a diagram showing a schematic configuration of the optical pickup device of the first embodiment, and FIG.
It is a figure for demonstrating the 2nd light receiver in (A).

FIG. 3 is a diagram for explaining the semiconductor laser unit in FIG. 2 (A).

FIG. 4A to FIG. 4D are diagrams for explaining deviation detection in the emission direction.

FIG. 5A and FIG. 5B are diagrams for explaining the detection of the deviation in the emission direction.

FIG. 6A and FIG. 6B are diagrams for explaining the relationship between the output signal of each light receiving element and the deviation of the emission direction.

FIG. 7A and FIG. 7B are diagrams for explaining deviation correction in the emission direction.

FIG. 8A to FIG. 8C are diagrams for explaining the second condenser lens, respectively.

9 (A) and 9 (B) are diagrams for explaining an example in which a deflection element and an optical element are integrated.

10A is a diagram showing a schematic configuration of the optical pickup device of the second embodiment, and FIG.
FIG. 11 is a diagram for explaining the light diffraction element in FIG.

FIG. 11A to FIG. 11C are views for explaining the detection of the deviation in the emission direction.

12 (A) to 12 (C) are diagrams for explaining displacement detection in the emission direction.

13 (A) to 13 (D) are diagrams for explaining the detection of the deviation in the emission direction when the partial light diffraction element is used.

14 (A) to 14 (C) are diagrams for explaining deviation detection in an emission direction when a partial light diffraction element is used.

FIG. 15 (A) is a diagram for explaining an example in which the second light receiver is housed in the same housing as the semiconductor laser unit and packaged, and FIG. 15 (B) is the first. FIG. 15C is a diagram for explaining an example in which the light receiver and the second light receiver are housed in the same housing as the semiconductor laser unit and packaged, and FIGS. 15C to 15F are respectively diagrams. It is a figure for demonstrating an example which integrated the reflected light diffraction element for 1 light receivers, and the branch optical element for 2nd light receivers.

[Explanation of symbols]

15 ... Optical disc, 20 ... Optical disc device, 23 ... Optical pickup (optical pickup device), 28 ... Reproduction signal processing circuit (correction means), 40 ... CPU (processing device), 51
... semiconductor laser unit (light source unit), 60 ... half mirror (branching optical means, deflecting element), 61 ... second light receiver, 62 ... second condenser lens (condensing means), 63 ... optical diffraction element ( Branching optical means, deflection element), 67 ... Second polarization beam splitter, 69 ... Beam shaping prism, 73
... Optical axis control circuit (optical axis deviation correction means, conversion means).

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5D118 AA01 AA18 AA20 BA01 CA13                       CC04 CC13 CD03 CD11 CF03                       CF05 DA19 DA20 DC06 DC07                 5D119 AA01 AA29 AA32 AA36 BA01                       EA02 EC15 JA24                 5D789 AA01 AA29 AA32 AA36 BA01                       EA02 EC15 JA24

Claims (8)

[Claims] 1. Recording and reproduction of information on an optical recording medium,
An optical pickup device which is used to perform at least reproduction among erasing and erasing, and which is arranged with its emitting end facing the recording surface of the optical recording medium; a light source unit; An optical system for guiding the light flux to the recording surface of the optical recording medium and for guiding the return light flux reflected on the recording surface to a predetermined light receiving position; a first light receiving element arranged at the light receiving position; and the light source unit. Is arranged on the optical path of the light flux emitted from
A branching optical means for optically branching the light flux; receiving a light flux branched from the optical path toward the recording surface by the branching optical means, and outputting a signal according to the deviation of the emission direction of the light flux emitted from the light source unit. A second light receiving element having a light receiving surface divided into at least two; light for correcting the optical axis shift of the light flux due to the emission direction shift based on the signal output from the second light receiving element An optical pickup device comprising: an axis deviation correcting means; 2. The light according to claim 1, further comprising a condensing unit which is arranged in the vicinity of the light receiving surface of the second light receiving element and condenses a light beam incident on the light receiving surface. Pickup device. 3. The branching optical means is a deflecting element which deflects at least a part of a peripheral portion of the light flux and guides it to a light receiving surface of the second light receiving element. The optical pickup device described. 4. The optical pickup device according to claim 3, wherein the deflecting element is integrated with another optical element that constitutes the optical system. 5. The conversion means for converting the signal output from the second light receiving element into a signal according to the intensity of the light emitted from the light source unit, further comprising: The optical pickup device according to any one of claims. 6. The first and second light receiving elements, at least a second light receiving element is housed and packaged in the same housing as the light source unit. 6. The optical pickup device according to any one of items 5 to 5. 7. An optical disc device for recording, reproducing, and erasing information on and from an optical disc, the optical pickup device according to claim 1, and the optical pickup device. An optical disc device comprising: a processing device for performing at least reproduction of the information recording, reproduction, and erasing using the output signal of the first light receiving element. 8. An optical disk apparatus for performing at least reproduction of information from, recording, and erasing on an optical disk, wherein the first and second light receiving elements are in the same housing as the light source unit. Claim 6 stored and packaged
An optical pickup device according to claim 1; a correction means for correcting a track error signal obtained from the output of the first light receiving element based on the signal output from the second light receiving element; the first light receiving element An optical disc device comprising: a processor for performing at least reproduction of the information recorded, reproduced, and erased by using the output signal of.