JPH07307029A - Optical recording / reproducing device - Google Patents

Abstract

(57) [Summary] [Configuration] The photodiode 107 for detecting the reflected light from the optical recording medium 101 via the objective lens 109 to obtain the servo signal, the semiconductor laser 103, and the objective lens 109 are movable in common. It is mounted on the frame 123 of the formula. A biaxial lens actuator 110 is provided which controls the focusing state of the irradiation light of the semiconductor laser 103 onto a predetermined track by moving the objective lens 109 by a servo signal. A linear motor 114 is provided to move the frame 123 across multiple tracks. [Effect] Since only the irradiation light side is controlled and the light receiving side is not controlled, by increasing the range for detecting transmitted light,
The means for servo control can be controlled separably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus for obtaining data information by a transmitted light beam from an optical recording medium.

[0002]

2. Description of the Related Art As a conventional optical recording / reproducing apparatus for obtaining data information by a light beam from an optical recording medium, there are a reflection type apparatus using the Kerr effect and a transmission type apparatus using the Faraday effect. The reflection type optical recording / reproducing apparatus using the Kerr effect reproduces data information recorded on the optical recording medium by the reflected light from the optical recording medium. In order to prevent linearly polarized light from changing to elliptical polarized light, many special optical elements with a small phase difference between P-polarized light and S-polarized light are required. B) The amount of light emitted from the objective lens is small. Therefore, there is a problem that a light beam generating means with a large output is required. In order to solve such a problem,
It is a transmission type optical recording / reproducing apparatus using the Faraday effect. FIG. 2 is a conceptual diagram of an optical recording / reproducing apparatus based on the Faraday effect. In the figure, the data information input to the input terminal 120 is supplied to the laser driver 117 and the magnet controller 116. Upon receiving an instruction from the magnet controller 116, a magnetic field is applied by the coil 111 in the desired recording direction on the optical recording medium 101. On the other hand, the light beam emitted from the semiconductor laser 103 instructed by the laser driver 117 is a collimator lens 104, a total reflection prism 108, an objective lens 109.
The light is irradiated onto the optical recording medium 101 via the light source, and the temperature rises like a spot. When the temperature approaches the Curie point, the magnetization of the optical recording medium 10 is reversed by the magnetic field generated by the coil 111, and the data is recorded.

Next, in the case of reproducing the data information, the linearly polarized beam emitted from the semiconductor laser 105 is transmitted through the medium 101 so that the plane of polarization is rotated by the direction of magnetization and the four-division stripe type sensor is passed through the polarizing plate 112. 201 is irradiated. The sensor 201 converts an optical signal into an electric signal, the electric signal is amplified by a head amplifier 204, and is separated into an information data signal and a servo signal in a signal separation circuit 205, and the information data signal is output from a terminal 119. .

The servo signal is also supplied to the focus actuator 202 and the tracker actuator 203.

Further, a track access signal is supplied to the terminal 122, and the retracking actuator 203 is driven by this signal. Here, the frame 123 is biaxial in the optical axis direction (the normal direction to the optical recording medium) and the direction perpendicular to the information recording track (in the plane of the optical recording medium) by the focus actuator 202 and the tracking actuator 203. Driven to. The frame 123 includes the semiconductor laser 103 and the collimator lens 10
4, the total reflection prism 108, the objective lens 109, the polarizing plate 112, and the sensor 201 are supported.

[0006]

However, the above-mentioned conventional optical recording / reproducing apparatus of the Faraday system has the following problems.

A) The entire frame 123 is driven in two axial directions by controlling focusing and tracking servo signals, and the weight of the entire frame 123 is large.
Access time becomes longer.

B) Tracking actuator 203
In order to coarsely move the frame 123 according to the track access signal and at the same time finely move the frame 123 by the servo signal, it is difficult to improve the tracking accuracy.
Even if it is forced, a large magnetic circuit and a large current are required. Therefore, the optical recording medium must be rotated at a low speed, resulting in a low transfer rate.

(C) The head amplifier 204 must amplify both the information data signal and the servo signal. However, both signals have different frequency bands. For example, since the information data is on the order of several MHz and the servo signal is on the order of several kHz, it is difficult to design an optimum head amplifier in each frequency band. Therefore, C / N is lowered.

The present invention overcomes the above-mentioned problems. In a Faraday type optical recording / reproducing apparatus, a means for obtaining a servo signal for tracking and focusing from a reflected light beam from an optical recording medium is provided. It is an object of the present invention to provide an optical recording / reproducing device which realizes a high transfer rate, a high C / N and a high speed access.

[0011]

An optical recording / reproducing apparatus of the present invention comprises a light generating means for generating a beam of irradiation light and the irradiation light on a predetermined track among a plurality of tracks on an optical recording medium. Optical means for converging light, and detecting means for detecting reflected light from the optical recording medium via at least a part of the optical means to obtain a servo signal. The light generating means and the optical means And an optical recording / reproducing apparatus in which the detecting means is mounted on a common movable frame, wherein at least a part of the optical means is moved by the servo signal to condense the irradiation light on the predetermined track. Drive means for controlling the optical system and moving means for moving the frame over the plurality of tracks.

Further, a light generating means for generating irradiation light on the beam, an optical means for condensing the irradiation light on a predetermined track among a plurality of tracks on the optical recording medium, and the optical recording medium are provided. Transmitted light detection means for detecting the transmitted light,
Reflected light detecting means for detecting reflected light from the optical recording medium via at least a part of the optical means to obtain a servo signal, the light generating means, the optical means, and the transmitted light detecting means. And an optical recording / reproducing apparatus in which the reflected light detecting means is mounted on a common frame, and moving means for moving the frame over a plurality of the tracks,
And an optical system driving unit for controlling at least a part of the optical unit by the servo signal to control a condensing state of the irradiation light on the predetermined track, and the transmitted light detecting unit has the driving unit. It is characterized in that it has a detection range that covers the moving range of the transmitted light that fluctuates according to the above.

[0013]

According to the above configuration of the present invention, the reflected light from the medium is photoelectrically converted by the sensor via the optical system for detecting the focus error and the tracking error,
It is amplified to low noise by a dedicated head amplifier that matches the servo signal band.

The high-quality error signal thus obtained drives the lens actuator 1 having a simple mechanism in which only the lens moves. As the tracking mechanism, a mechanism that changes the incident angle of light to the objective lens such as a galvanometer mirror may be used.

On the other hand, the transmitted light from the medium is photoelectrically converted by a sensor having a sufficient size, and is amplified while maintaining a high C / N by a head amplifier adapted to the signal band.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a conceptual diagram of an embodiment of the optical recording / reproducing apparatus of the present invention. The data information signal supplied to the data input terminal 120 is input to the magnet controller 116 and the laser driver 117. A magnetic field is applied to the medium 101 by the coil 111 according to an instruction from the magnet controller 116, and a medium 101 is generated by a light beam emitted from the semiconductor laser 103 according to an instruction from the laser driver 117.
The point that the magnetic moment inside is reversed and data information is recorded is the same as the conventional method.

Next, at the time of reproduction, the 780 nm light beam emitted from the semiconductor laser 103 which is the light beam generating means is collimated by the collimator lens 104 and is incident on the surface 121 having a beam shaping function. The light made circular by the surface 121 is made completely linearly polarized by the polarization beam splitter 105 having an S-polarized light reflectance of 100% and a P-polarized light transmittance of 50%, and is bent at a right angle by the total reflection prism 108 to be the objective lens 109. Incident. The objective lens 109 is an optical unit that focuses light on the optical recording medium. The optical recording medium 101 includes GdTbFe, TbFeco or D
A magnetic book film such as yFeco is formed. Objective lens 1
The light beam focused on the optical recording medium 101 to have a diameter of 1.6 μm by 09 is detected by the polarizing plate 112.
The detected light beam is photoelectrically converted by a data PIN photodiode 113 having a diameter of 4 mm. The photoelectrically converted electric signal is a head amplifier 115 dedicated to data information.
Amplified by and output from the terminal 119.

On the other hand, from the surface of the optical recording medium 101, a light beam of a constant light quantity is reflected and again collimated by the objective lens 109. The reflected light beam is applied to the polarized beam splitter 105 via the total reflection prism 108, and the polarized beam splitter reflects half the light amount of the light beam and is applied to the knife edge 124. The knife edge 124 has a semi-circular light beam spot, and the semi-circular light beam is condensed on a 4-division servo PIN photodiode 107 having a diameter of 1 mm via a condenser lens 106. In FIG. 1, the condenser lens 106 and the photodiode 107 are arranged parallel to the paper surface, but they may be arranged in the direction perpendicular to the paper surface.

The photoelectrically converted signal from the PIN photodiode 107 is amplified and calculated by the servo dedicated head amplifier 118 to obtain a focus error signal based on the knife edge method and a tracking error signal based on the push-pull method. To be

Servo signals, which are the focus error signal and the tracking error signal, are supplied to the biaxial lens actuator 110, and the biaxial lens actuator 1 is operated.
Focusing / tracking drive 10 is performed under the control of this servo signal.

On the other hand, the optical recording medium 101 of the frame 123
The linear motor 1
14 is performed. The linear motor 114 is driven under the control of the track access signal 122 and the tracking error signal.

The optical recording medium 101 has a disk shape and a diameter of 90 mm or 130 mm, and a group of ⅛ wavelength depth has a 1.6 μm pitch spiral or circular center on the optical recording medium. It is formed in a circular shape.

Further, the optical recording medium 101 is rotated by the spindle motor 102 at a constant angular velocity of 1800 RPM or at a constant linear velocity of at most 1800 RPM.

In this embodiment, the unformatted capacity is 200 MB, the average access time is 40 ms, and the transfer rate is 6.
Mbit / 8 was realized at a high C / N high enough to obtain an error rate of ^10-12 after error correction.

FIG. 3 is a conceptual diagram showing another embodiment of the tracking mechanism portion of the present invention.

As a tracking mechanism, a mechanism 301 for changing the incident angle of light incident on the objective lens is provided.

Reference numeral 301 denotes a galvanometer mirror, which is rotated by a tracking error signal and changes the incident angle to the objective lens 109 to perform tracking.

At this time, since the PIN photodiode for data 113 is sufficiently large, all the transmitted light can be received and the signal amplitude does not decrease.

The broken line in the figure conceptually shows this situation. The objective lens 109 is focused by a focusing actuator 302 that moves only in the optical axis direction.

Other parts not shown in FIG. 3 are the same as those of the embodiment of FIG. 1 and have the same specifications.

[0031]

According to the present invention, since only the irradiation light side is controlled and the light receiving side is not controlled, it is possible to separate the servo control means by increasing the range for detecting the transmitted light. Have.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an embodiment of an optical recording / reproducing apparatus of the present invention.

FIG. 2 is a conceptual diagram of an example of a conventional optical recording / reproducing apparatus.

FIG. 3 is a conceptual diagram of another embodiment of the tracking mechanism of the optical recording / reproducing apparatus of the present invention.

[Explanation of symbols]

 101 ... Optical recording medium 102 ... Sbindle motor 103 ... Semiconductor laser 104 ... Collimator lens 105 ... Polarizing prism 106 ... Condenser lens 107 ... Servo 4-division PIN photo Diode 108 ・ ・ ・ Total reflection prism 109 ・ ・ ・ Objective lens 110 ・ ・ ・ Biaxial lens actuator 111 ・ ・ ・ Coil 112 ・ ・ ・ Polarizing plate 113 ・ ・ ・ PIN photodiode for data 114 ・ ・ ・ Linear motor 115 ... Head amp for data signal 116 ... Magnet controller 117 ... Laser driver 11 ... Head amp for servo signal 119 ... Output data 120 ... Input data 121 ... Beam shaping surface 122 ... Track access signal 123 ... F Lame 124 ... Knife Edge 201 ... Quadrant Stripe Photodiode 202 ... Focusing Actuator 203 ... Tracking Actuator 204 ... Head Amp 205 ... Signal Separation Circuit 301 ... Galvano Mirror 302 ... Focusing Actuator

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[Procedure amendment]

[Submission date] April 24, 1995

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

Further, a light generating means for generating a beam of irradiation light, an optical means for condensing the irradiation light on a predetermined track among a plurality of tracks on the optical recording medium, and the optical recording medium are provided. Transmitted light detection means for detecting the transmitted light,
Reflected light detecting means for detecting reflected light from the optical recording medium via at least a part of the optical means to obtain a servo signal, the light generating means, the optical means, and the transmitted light detecting means. And an optical recording / reproducing apparatus in which the reflected light detecting means is mounted on a common frame, and moving means for moving the frame over a plurality of the tracks,
And an optical system driving unit for controlling at least a part of the optical unit by the servo signal to control a condensing state of the irradiation light on the predetermined track, and the transmitted light detecting unit has the driving unit. It is characterized in that it has a detection range that covers the moving range of the transmitted light that fluctuates according to the above.

Claims (2)

[Claims] 1. A light generating means for generating a beam of irradiation light, an optical means for condensing the irradiation light on a predetermined track among a plurality of tracks on an optical recording medium, and for obtaining a servo signal. A detection means for detecting reflected light from the optical recording medium via at least a part of the optical means, and the light generation means, the optical means and the detection means are mounted on a common movable frame. And a drive unit of an optical system that controls at least a part of the optical unit by the servo signal to control a condensed state of the irradiation light on the predetermined track, and the frame. An optical recording / reproducing apparatus comprising: a moving unit that moves over a plurality of the tracks. 2. A light generating means for generating irradiation light on a beam, an optical means for condensing the irradiation light on a predetermined track among a plurality of tracks on the optical recording medium, and the optical recording medium. The transmitted light detecting means for detecting transmitted light; and the reflected light detecting means for detecting reflected light from the optical recording medium to obtain a servo signal via at least a part of the optical means. An optical recording / reproducing apparatus in which the generating means, the optical means, the transmitted light detecting means, and the reflected light detecting means are mounted in a common frame, the moving means moving the frame over a plurality of the tracks, and the servo signal. Drive means of an optical system for moving at least a part of the optical means to control a condensed state of the irradiation light on the predetermined track, and the transmitted light detecting means drives the driving means. An optical recording / reproducing apparatus having a detection range that covers the moving range of the transmitted light that varies depending on the means.