JPH06314450A - Optical pickup device - Google Patents

Abstract

(57) [Summary] [Structure] Of the laser beams emitted from the laser diode 2, the laser beam on the right side of the optical axis is the optical rotation plate 5.
The right optical rotatory plate 5R rotates the laser beam on the left side by a predetermined angle, and the left optical rotatory plate 5L rotates the laser beam on the left side by a predetermined angle to irradiate the magneto-optical disk 1. The reflected light related to the laser beam passing through the right rotatory plate 5R is incident on the left rotatory plate 5L and further rotated rightward by a predetermined angle, and the reflected light related to the laser beam passing through the left rotatory plate 5L is The light is incident on the right optical rotation plate 5R and further rotated to the left by a predetermined angle. Since the reflected light has a traveling direction different from that of the laser beam, the optical path of the reflected light is bent by a predetermined amount by the lotion prism 4 and is applied to the photodetector 7. The photodetector 7 receives the reflected light and detects a focus error, a tracking error, a magneto-optical recording signal, and the like. [Effect] A high-quality magneto-optical recording signal can be taken out with a simple configuration.

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 suitable for use as an optical system such as a magneto-optical disk recording / reproducing apparatus for recording / reproducing desired recording information on / from a magneto-optical disk.

[0002]

2. Description of the Related Art Today, large storage capacity,
Magneto-optical discs have come to be widely used for recording / reproducing recorded data because of the good preservation of the recorded data and the fact that they can be easily rewritten.

An optical pickup device provided in a magneto-optical disk recording / reproducing apparatus for recording / reproducing recorded data on / from the magneto-optical disk includes, for example, a semiconductor laser and a collimator lens for collimating emitted light from the semiconductor laser. , Is provided between the semiconductor laser and the objective lens, which is provided between the objective lens that collects the emitted light that is collimated by the collimator lens and irradiates the recording surface of the magneto-optical disk, and is reflected by the recording surface of the magneto-optical disk. A first polarization beam splitter for separating a part of the reflected light thus reflected, an analyzer for detecting a part of the reflected light separated by the first polarization beam splitter, and a level of light transmitted through the analyzer It is composed of a photo detector or the like for detecting the.

The optical pickup device having such a structure condenses the laser beam emitted from the semiconductor laser, irradiates the recording surface of the magneto-optical disk with the reflected light, and reflects one of the reflected lights on the recording surface. The part is separated by the first polarization beam splitter, and the level of a component having a predetermined polarization plane, that is, a predetermined light oscillation plane, out of a part of the separated reflected light is detected by the photodetector. The recorded data recorded on the magneto-optical disk is reproduced.

As the above-mentioned analyzer, a "sheet analyzer" is generally used, but this sheet analyzer has a problem that the S / N ratio is low because the "extinction ratio" is low. For this reason, a half-wave plate is provided in place of the above-mentioned analyzer in the optical pickup device which is currently the mainstream.

In the optical pickup device provided with the half-wave plate, the reflected light separated by the first polarization beam splitter is further reflected by the half-wave plate and the second polarization beam splitter by P Separated into wave component and S wave component,
The levels of the P-wave component and the S-wave component are detected by two photodetectors, and the difference between these levels is detected by a differential amplifier, whereby the recorded data recorded on the magneto-optical disk is reproduced. ing.

[0007]

However, the optical pickup device provided with the above-mentioned half-wave plate must be provided with a total of two polarization beam splitters, that is, the first and second polarization beam splitters. There was a problem that the number of points increased and the production cost increased.

Further, since the reflected light separated by the first polarization beam splitter is further separated into two components by the second polarization beam splitter, it is necessary to establish an optical path for each component. However, there is a problem that the device itself becomes large in size in addition to the troublesome alignment.

The present invention has been made in view of the above-mentioned problems, and relates to an optical pickup device capable of reducing the number of parts to be manufactured in a small size and at a low cost and reducing troublesome alignment. .

[0010]

An optical pickup device according to the present invention comprises a laser beam emitting means for emitting a laser beam for irradiating a magneto-optical disk, and a laser beam from the laser beam emitting means as parallel light. A collimator lens that emits and converges and emits the reflected light generated by irradiating the magneto-optical disk with the laser beam, and the laser beam is transmitted without bending the optical path, and the reflected light is the laser beam. Since the traveling directions are different, the Rochon prism which bends the optical path by a predetermined amount and emits it, the first optical rotator which rotatively emits the laser beam and the reflected light by a predetermined angle, and the incident laser beam and the reflected light And a second optical rotator that rotatively emits light at a predetermined angle, contrary to the first optical rotator. And an objective for diverting the laser beam from the laser beam emitting means to irradiate the magneto-optical disc with the optical rotation means provided with the optical axis of the reflected light as a boundary and emitting the reflected light as parallel light. A lens and a photo-detecting means for detecting a tracking error, a focus error, and a magneto-optical recording signal by receiving the reflected light converged by the collimator lens by bending the optical path by a predetermined amount by the lotion prism. The above problems are solved.

[0011]

In the optical pickup device according to the present invention, the laser beam emitted from the laser beam emitting means is incident on the collimator lens. The collimator lens emits the laser beam as parallel light. The collimated laser beam is then incident on the Rochon prism.

The Rochon prism has a characteristic that the optical path of the incident light is bent by a predetermined amount depending on the traveling direction, and in the case of the traveling direction of the laser beam, it is emitted without bending the optical path. This laser beam is then incident on the optical rotation means.

The optical rotator is formed, for example, by a right optical rotator which is the first optical rotator on the right side and a left optical rotator which is the second optical rotator on the left, with the optical axis of the laser beam as a boundary. Among the laser beams from the prism, the laser beam on the right side of the optical axis as a boundary is rotatably emitted by the right optical rotator at a predetermined angle, and the laser beam on the left side of the optical axis as a boundary is emitted by the left optical rotator. In contrast to the right optical rotatory plate, the light is rotatably emitted at a predetermined angle.

As a result, although apparently one laser beam, laser beams having different optical rotation angles are formed on the right and left sides of the optical axis. This laser beam is converged by the objective lens and applied to the magneto-optical disk.

Next, by irradiating the magneto-optical disk with the laser beam through the objective lens, reflected light is generated. The reflected light is collimated by the objective lens and emitted. Of the reflected light made into the parallel light, the reflected light relating to the laser beam emitted through the right rotatory plate in the optical rotatory means is incident on the left rotatory plate in the optical rotatory means and left-rotated in the optical rotator. The reflected light relating to the laser beam emitted through the optical plate enters the right optical rotatory plate in the optical rotator.

The traveling direction of the reflected light incident on the optical rotation means is opposite to the traveling direction of the laser beam emitted from the laser beam emitting means. Therefore, the reflected light incident on the left optical rotator is further rotated by a predetermined angle and emitted, and the reflected light incident on the right optical rotator is opposite to the reflected light incident on the left optical rotator. Further, the light is rotated by a predetermined angle and emitted.

The reflected light that has passed through the optical rotation means is then incident on the Rochon prism.

As described above, the Rochon prism has a characteristic that its optical path is bent by a predetermined amount depending on the traveling direction of light and is emitted. Further, the reflected light has a traveling direction different from that of the laser beam. Therefore, the reflected light that has entered the lotion prism is emitted with its optical path bent by a predetermined amount. The reflected light emitted by bending the optical path by a predetermined amount is then incident on the collimator lens.

The collimator lens converges and emits the reflected light. The reflected light thus converged is applied to the light detecting means.

In the above-mentioned light detecting means, for example, the light receiving portion is divided into four, and a focus error is detected by the astigmatism method,
The tracking error is detected by the radial push-pull method, the magneto-optical recording signal is detected by the transient push-pull method (differential detection method), and the sum of the levels of the reflected light received by the four light-receiving sections is detected. RF signal is detected.

[0021]

Embodiments of the optical pickup device according to the present invention will be described below with reference to the drawings.

The optical pickup device according to the present invention can be applied as an optical system of a magneto-optical disc recording / reproducing device for recording and reproducing desired recording data on the magneto-optical disc 1 as shown in FIG. 1, for example.

In FIG. 1, the optical pickup device according to the present embodiment emits a laser beam having a strong recording level during recording and a laser beam having a weak reproducing level during reproduction (laser beam). (Emission means) 2, a collimator lens 3 that emits the laser beam as parallel light and converges and emits the reflected light that is generated by irradiating the magneto-optical disk 1 with the laser beam, depending on the traveling direction. It has a characteristic of bending the optical path. The laser beam is emitted without bending the optical path, and the reflected light generated by irradiating the magneto-optical disk 1 with the laser beam is emitted by bending the optical path by a predetermined amount. It has a lotion prism 4.

Further, in the above optical pickup device, the right optical rotator which circulates the laser beam and the reflected light on the right side by a predetermined angle to the right with the optical axes of the incident laser beam and the reflected light as boundaries, and emits them. 5R (first optical rotator) and an optical rotatory plate (optical rotator) having a left optical rotator 5L (second optical rotator) that turns the incident laser beam and reflected light leftward by a predetermined angle. 5 and the laser beam from the laser diode 2 incident through the optical rotation plate 5 is converged and applied to the magneto-optical disk 1.
The tracking lens signal, the focus error signal, the magneto-optical recording signal, and the RF signal are formed by receiving the objective lens 6 that emits the reflected light as parallel light and the reflected light whose optical path is bent by a predetermined amount by the lotion prism 4. It has a photodetector (light detecting means) 7.

The laser diode 2 and the photodetector 7 are provided adjacent to each other in a box-shaped laser unit 11. The laser unit 11 is provided with holes 11a so as not to block the laser beam emitted from the laser diode 2 and the reflected light emitted to the photodetector 7 through the lotion prism 4. It should be noted that, for example, the laser unit 11 is configured so as to shield all light except for the hole 11a.

Next, the operation of the optical pickup device according to this embodiment having such a configuration will be described.

First, at the time of recording or reproduction, the laser diode 2 emits a laser beam of, for example, an S-polarized component as shown in FIG. 2A. This S-polarized component laser beam is incident on the collimator lens 3. The collimator lens 3 emits the S-polarized component laser beam as parallel light. The laser beam made into the parallel light is incident on the lotion prism 4.

The lotion prism 4 has a characteristic that its optical path is bent by a predetermined amount according to the traveling direction of light.
In the case of the traveling direction of the laser beam, the optical path of the laser beam is emitted without bending. The laser beam that has passed through the lotion prism 4 is then incident on the optical rotation plate 5.

As described above, the optical rotation plate 5 is formed by the right optical rotation plate 5R on the right side and the left optical rotation plate 5L on the left side with the optical axis of the laser beam as a boundary. Therefore, the optical rotation plate 5 is
Of the laser beams incident through the lotion prism 4, the laser beam on the right side of the optical axis is separated by a predetermined amount (+) from the right optical rotatory plate 5R as shown in FIG. 2B.
[alpha]) The light is rotated rightward and emitted (+ [alpha] + [theta] k: [theta] k = Kerr rotation angle), and the laser beam on the left side of the optical axis as a boundary is moved by the left optical rotation plate 5L for a predetermined amount ((c)). -Α) Rotate to the left and emit (-α + θk:
θk = car rotation angle).

As a result, although apparently one laser beam, laser beams having different polarization directions on the right and left sides of the optical axis are formed. This laser beam is converged by the objective lens 6 and applied to the magneto-optical disk 1.

Next, by irradiating the magneto-optical disk 1 with the laser beam through the objective lens 6, reflected light is generated. The reflected light is collimated by the objective lens 6 and emitted. Of the reflected light from the objective lens 6, the reflected light (+ α + θk) related to the laser beam emitted through the right optical rotatory plate 5R in the optical rotatory plate 5.
Is the reflected light (-α + θk) related to the laser beam that is incident on the left optical rotatory plate 5L in the optical rotatory plate 5 and is emitted through the left optical rotatory plate 5L in the optical rotatory plate 5 is the right optical rotator in the optical rotatory plate 5. It is incident on the light plate 5R.

The traveling direction of the reflected light incident on the optical rotatory plate 5 is opposite to the traveling direction of the laser beam emitted from the laser diode 2. Therefore, the reflected light that has entered the left optical rotation plate 5L is further rotated by a predetermined amount (+ α) to the right as shown in FIG.
α + θk), the reflected light incident on the right optical rotation plate 5R is
As shown in (e) of the figure, the light is further rotated leftward by a predetermined amount (-α) and emitted (-2α + θk).

The reflected light that has passed through the optical rotation plate 5 is then incident on the lotion prism 4.

As described above, the lotion prism 4
Has a characteristic that its optical path is bent by a predetermined amount depending on the traveling direction of light, and in the case of the traveling direction of the reflected light, the optical path of the reflected light is bent by a certain amount and emitted. The reflected light whose optical path is bent by the lotion prism 4 is converged by the collimator lens 3 and is applied to the photodetector 7.

The reflected light is transmitted through the lotion prism 4 so that the reflected light (+ 2α + θk) passing through the left optical rotation plate 5L has a polarization angle of sin (+ 2α + θk) as shown in FIG. 2 (f). And the reflected light (-2α + θk) that has passed through the right rotatory plate 5R is a sin-polarized light component having a sin as shown in FIG.
The reflected light is a P-polarized component having a polarization angle of (−2α + θk), and is irradiated on the photodetectors 7.

The inside of the photodetector 7 is divided into four, for example, first to fourth light receiving portions 7a to 7c as shown in FIG. 3, and the light receiving portions 7a to 7c reflect the light from the collimator lens 3. Receive light. Then, based on the level of the reflected light received by each of the light receiving units 7a to 7c,
For example, the first differential amplifier circuit 1 is formed by the so-called astigmatism method.
The focus error is detected in 2 and the tracking error is detected by the radial push-pull method. Then, the focus error signal and the tracking error signal are supplied to, for example, a system controller (not shown) via the output terminal 14.

Based on the focus error signal, the system controller controls, for example, the objective lens 6 to be vertically driven so that the laser beam applied to the magneto-optical disk 1 is focused, and the tracking error. Based on a signal, the objective lens 6 is driven and controlled to the left and right so that the laser beam scanning the magneto-optical disk 1 is on-track.

As a result, recording / reproduction can be performed with accurate focusing and tracking.

In the photodetector 7, the second differential amplifier circuit 13 uses the transient push-pull method (differential detection method) based on the level of the reflected light received by each of the light receiving sections 7a to 7c. Then, the magneto-optical recording signal is detected, and the RF signal is detected by detecting the sum of the levels of the reflected light received by the four light receiving portions. Then, the magneto-optical recording signal and the RF signal are supplied to the magneto-optical recording signal processing circuit (not shown) through the output terminal 15.

As described above, the so-called differential detection method for detecting the difference in the level of the light receiving area is difficult to realize unless the optical system has a high extinction ratio that determines the performance of the common mode rejection ratio. However, since the optical pickup device according to the present embodiment detects the reflected light of the laser beam using the lotion prism 4, in-phase removal can be performed up to an extinction ratio determined by the characteristics of the lotion prism 4. Therefore, it is possible to achieve a high-quality magneto-optical system having a high common mode rejection ratio.

Further, the reflection film of the ordinary beam splitter needs to be mass-produced in consideration of the optical phase characteristic (retardation), but the cost is high, but the optical pickup device according to the present embodiment has the above lotion. Since the prism 4 is used, retardation does not occur. Therefore, it is possible to contribute to cost reduction because it is not necessary to mass-produce the retardation.

Further, only the light quantity of the reflected light is detected by using the lotion prism 4, and the light quantity of the outward path is 10
Since 0% is transmitted, the coupling efficiency can be improved.

Further, the rotation angles of the right rotatory plate 5R and the left rotatory plate 5L are arbitrarily set without affecting the outward coupling efficiency, and the light amount of the reflected light with which the photodetector 7 is irradiated is arbitrarily set. can do.

Specifically, by changing the angle of rotation of each of the right rotatory plate 5R and the left rotatory plate 5L to 0 to 45 degrees, the amount of reflected light radiated to the photodetectors 7 and 8 is 0% to 45%. It can be changed to 100%.

Therefore, it is possible to increase the degree of freedom in designing an amplifier circuit in the subsequent stage such as an amplifier circuit for the magneto-optical recording signal, the focus error signal and the tracking error signal. Therefore, the amplification factor of the amplification circuit in the latter stage can be set so that the amplification degree is appropriate according to the signal, and the S / N ratio can be improved.

Further, the lotion prism 4 can be used for forming the magneto-optical recording signal, and it is possible to handle even the focused light without degrading the quality of the magneto-optical recording signal. Therefore, a magneto-optical laser coupler can be realized.

Further, the optical rotation plate 5 only changes the rotation angle and does not change the phase difference unlike the wavelength plate. Therefore, it is not affected by the variation in the oscillation wavelength of the laser diode 2. Therefore, it is possible to handle laser beams having two or more wavelengths in the same optical system.

Further, in the optical rotation plate 5, even if the right optical rotation plate 5R and the left optical rotation plate 5L have different optical rotation angles,
As for the two reflected lights, the laser beam is the right optical rotation plate 5R.
And the left optical rotatory plate 5L are formed in order, and the laser beam is formed via the left optical rotatory plate 5L and the right optical rotatory plate 5R in order, so that the levels of the two reflected lights can be made equal. Therefore, it is possible to increase the degree of freedom in the specifications of each element used in the optical pickup device.

The lotion prism 4 can be manufactured at low cost. Moreover, in the optical pickup device according to the present embodiment, since only one Rochon prism 4 is used, the optical path can be greatly shortened.
Further, the optical rotation plate 5 can also be manufactured at a lower cost than the Wollaston prism.

Therefore, the optical pickup device itself can be downsized and the cost can be reduced, and the troublesome positioning work can be reduced.

In the above description of the embodiment, the optical rotation plate 5 in which the right optical rotation plate 5R and the left optical rotation plate 5L are combined is used as the optical rotation means, but this changes the optical axis of the 1/2 wavelength plate. You may make it use what combined two sheets.

[0052]

As is apparent from the above description, in the optical pickup device according to the present invention, the laser beam emitting means, the collimator lens, the lotion prism, the optical rotation means, and the objective lens are provided in order along the optical path of the laser beam, With a simple configuration in which the photodetection means is provided at a position where the reflected light whose optical path is bent by the Rochon prism is converged by the objective lens, 100% of the reflected light is utilized, the coupling efficiency is improved, and high quality is achieved. It is possible to form and output a magneto-optical recording signal, a focus error signal, a tracking error signal, and the like.

Moreover, since only one Rochon prism is used as a means for changing the optical path of light, the number of parts can be reduced and the optical path can be greatly shortened, and the optical pickup device can be made compact and compact. Low cost can be achieved. Moreover, since the optical path can be greatly shortened, it is possible to reduce the alignment of the photodetection means.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment in which an optical pickup device according to the present invention is applied to an optical system of a magneto-optical disk recording / reproducing device.

FIG. 2 is a schematic diagram for explaining an optical rotation angle of a laser beam and reflected light through each part of the optical pickup device according to the above-mentioned embodiment.

FIG. 3 is a schematic view of a photodetector provided in the optical pickup device according to the above embodiment.

[Explanation of symbols]

1 ... Magneto-optical disk 2 ... Laser diode 3 ... Collimator lens 4 ...・ Rotion prism 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Optical plate 5R ・ ・ ・ ・ ・ ・ ・ Right polar plate 5L ・ ・ ・ ・ ・ ・ ・ Left polar plate 6 ・ ・ ・..Objective lens 7 ... Photodetector 7a ..... First photodetector section of photodetector 7b .... Second photodetector section of photodetector 7c ... ・ ・ ・ Third light receiving portion of photodetector 7d ・ ・ ・ ・ ・ ・ Fourth light receiving portion of photodetector 11 ・ ・ ・ ・ ・ ・ ・ ・ Laser unit 11a ・ ・ ・・ ・ ・ ・ ・ Laser unit hole 12 ・ ・ ・ ・ ・ ・ ・ ・ First differential amplifier circuit 13 ・ ・ ・・ Second differential amplifier circuit ・ ・ ・ ・ ・ ・ ・ Output terminal for focus error signal etc. ・ ・ ・ ・ ・ ・ ・ ・ ・ Output terminal for magneto-optical recording signal etc.

[Procedure amendment]

[Submission date] March 15, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

An optical pickup device according to the present invention emits a laser beam for irradiating a magneto-optical disk, a laser beam emitting means, and a laser beam emitted from the laser beam emitting means as parallel light, and at the same time, the laser beam is emitted from the laser beam emitting means. A collimator lens that converges and emits reflected light generated by the beam irradiating the magneto-optical disk, and the laser beam is transmitted without bending the optical path, and the reflected light has a polarization direction different from that of the laser beam. The lotion prism that bends the optical path by a predetermined amount and emits the light, the first optical rotation unit that rotates and emits the laser beam and the reflected light at a predetermined angle, and the incident laser beam and the reflected light On the contrary to the optical rotator, the second optical rotator which rotatively emits light at a predetermined angle and emits the laser beam and the reflected light. Optical rotation means provided with the axis as a boundary, and a laser beam from the laser beam emitting means is converged and applied to the magneto-optical disk,
The optical path of the reflected light is emitted as parallel light and the optical path is bent by the lotion prism by a predetermined amount, and the reflected light converged by the collimator lens is received to detect tracking error, focus error, and magneto-optical recording signal. The above-mentioned problems are solved by having a light detection unit.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

The Rochon prism has a characteristic that the optical path of incident light is bent by a predetermined amount depending on the difference in polarization direction, and in the case of the polarization direction of the laser beam, the light is emitted without bending the optical path. This laser beam is then incident on the optical rotation means.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

As described above, the Rochon prism has a characteristic that the optical path thereof is bent by a predetermined amount depending on the polarization direction of light and then emitted. Further, the reflected light has a polarization direction different from that of the laser beam. Therefore, the reflected light incident on the Rochon prism is emitted after the optical paths of only the components having different polarization directions are bent by a predetermined amount. The reflected light emitted by bending the optical path by a predetermined amount is then incident on the collimator lens.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

In the above-mentioned light detecting means, for example, a light receiving portion is divided into four, a focus error is detected by an astigmatism method, a tracking error is detected by a radial push pull method, and a tangential push pull method (differential detection). Law)
Then, the magneto-optical recording signal is detected, and the RF signal is detected by detecting the sum of the levels of the reflected light received by the four light receiving portions.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

First, at the time of recording or reproducing, the laser diode 2 emits a laser beam of, for example, a P-polarized component as shown in FIG. 2A. The P-polarized component laser beam is incident on the collimator lens 3. The collimator lens 3 emits the P-polarized component laser beam as parallel light. The laser beam made into the parallel light is incident on the lotion prism 4.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

The lotion prism 4 has a characteristic that its optical path is bent by a predetermined amount according to the polarization direction of light, and in the case of the traveling direction of the laser beam, the optical path of the laser beam is emitted without bending. The laser beam that has passed through the lotion prism 4 is then incident on the optical rotation plate 5.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

As described above, the optical rotation plate 5 is formed by the right optical rotation plate 5R on the right side and the left optical rotation plate 5L on the left side with the optical axis of the laser beam as a boundary. Therefore, the optical rotation plate 5
Among the laser beams incident through the lotion prism 4, the right side laser beam with respect to the optical axis is directed to the right by a predetermined amount (+ α) as shown in FIG. The laser beam on the left side is rotated by a predetermined amount (-α) to the left by the left optical rotatory plate 5L and emitted from the optical axis as a boundary.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction content]

Next, by irradiating the magneto-optical disk 1 with the laser beam through the objective lens 6, reflected light is generated. The plane of polarization of the reflected light rotates by θk (= Kerr rotation angle) due to the phenomenon called the Kerr effect, which rotates in accordance with the direction of magnetization of the data recorded on the magneto-optical disk 1. Then, the reflected light whose polarization plane is rotated by θk is collimated by the objective lens 6 and emitted. Of the reflected light from the objective lens 6, the reflected light (+ α + θk) related to the laser beam emitted through the right optical rotatory plate 5R in the optical rotatory plate 5 is incident on the left optical rotatory plate 5L in the optical rotatory plate 5. The reflected light (−α + θ) related to the laser beam emitted through the left optical rotation plate 5L in the optical rotation plate 5 is generated.
k) is incident on the right optical rotation plate 5R in the optical rotation plate 5.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

As described above, the Rochon prism 4 has a characteristic that its optical path is bent by a predetermined amount depending on the polarization direction of light. In the case of the polarization direction of the reflected light, the optical path of the reflected light is divided by a predetermined amount. Bend and emit. The reflected light whose optical path is bent by the lotion prism 4 is converged by the collimator lens 3 and is applied to the photodetector 7.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

The magnitude of the reflected light whose optical path is bent by passing through the lotion prism 4 is the reflected light (+ 2α + θk) that has passed through the left optical rotation plate 5L.
Is reflected light of the S-polarized component having a polarization angle of sin (+ 2α + θk) as shown in FIG. 2 (f), and the reflected light (−2α + θk) through the right rotatory plate 5R is shown in FIG. The reflected light is the S-polarized light component having a polarization angle of sin (-2α + θk) as shown in FIG. Then, each of these reflected lights is applied to the photodetector 7.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

The photodetector 7 uses the tangential push-pull method (differential detection method) by the second differential amplifier circuit 13 based on the level of the reflected light received by each of the light receiving units 7a to 7c. An RF signal is detected by detecting the magneto-optical recording signal and detecting the sum of the levels of the reflected light received by the four light receiving portions. Then, the magneto-optical recording signal and the RF signal are supplied to the magneto-optical recording signal processing circuit (not shown) through the output terminal 15.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Delete

[Procedure Amendment 14]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (1)

[Claims] 1. A laser beam emitting means for emitting a laser beam for irradiating a magneto-optical disk, a laser beam emitted from the laser beam emitting means as parallel light, and the laser beam irradiating the magneto-optical disk. The reflected light generated by the reflected light is converged and emitted, and the laser beam is transmitted without bending the optical path. Since the reflected light has a different traveling direction from the laser beam, the optical path is bent by a predetermined amount. A lotion prism that emits light, a first optical rotator that rotatively emits the laser beam and reflected light at a predetermined angle, and an incident laser beam and reflected light that are opposite to those of the first optical rotator. And a second optical rotator that rotatively emits the light at an angle of 5 ° and is provided with the optical axis of the laser beam and the reflected light as a boundary. A step, a laser beam from the laser beam emitting means is converged and applied to the magneto-optical disk, and the reflected light is emitted as parallel light, and the optical path is bent by a predetermined amount by the lotion prism,
An optical pickup device comprising: a light detecting unit that receives the reflected light converged by the collimator lens and detects a tracking error, a focus error, and a magneto-optical recording signal.