JPH09270148A - Optical head device in which recorded state can be confirmed at the time of recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical head which can confirm a recording state at the time of recording using a single beam laser. SOLUTION: In a phase variation light head, a recording state is confirmed based on a signal in which outgoing light from a laser 101 and reflected light from an optical disk 109 are differentially detected. Two optical sensors 112, 115 are arranged at the same position in a light path system to take matching between this differential amplifier 118 and two optical sensors 112, 115. Differential output between a signal detected from surface reflected light of a complex prism 107 in which a beam of outgoing light from the laser is formed and a signal detected from reflected light from the optical disk is obtained, a D type flip-flop is triggered by rise and fall of this signal, and a signal already recorded is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head device, and more particularly to an optical head device suitable for use in a digital data optical disk recorder or a digital video optical disk recorder and capable of confirming a recording state at the time of recording. Regarding

[0002]

2. Description of the Related Art Research on an external storage device having a high-speed accessibility of a magnetic disk of an information processing device such as a computer and a large-capacity memory of an optical disk is rapidly progressing.
All the next-generation disk devices are sure to be optical disk devices in terms of high transfer rate, high-speed random access, storability of large-capacity memory and medium, non-contact medium durability, and the like.

In this optical disk device (optical disk recorder), it is possible to immediately confirm the recorded state.
It is required for digital data optical disk recorders and video optical disk recorders. That is, if it is not recorded correctly, it is impossible to record the work or program intended by the author even if the work is rewritten, the camerawork is rewritten, or the data is edited.

Conventionally, in an optical disc apparatus, in order to confirm the recording state with a single optical head, it is necessary to write once and confirm the recorded portion after one rotation. A rotation waiting time was required, and continuous writing was impossible.

As a solution to this problem, there is a method in which a plurality of optical heads are arranged in the same optical disk device and the plurality of optical heads are operated synchronously based on the track address. The configuration that arranges the recording head and the reproducing head is
Although the rotation waiting time of the optical disk can be shortened, the optical head is expensive.

Therefore, if a single optical head can immediately confirm the recording state of the optical disk at the time of recording, high speed and continuous recording is possible.

FIG. 4 shows the structure of a conventional optical head that enables recording confirmation by the two-beam method for a phase change medium.

Referring to FIG. 4, the two beams emitted from the two-beam laser 401 are converted into two parallel beams by a collimator lens 402, and a beam shaping prism 403, a polarization beam splitter 404, a 45 degree mirror 405, and a quarter beam.
The light is transmitted through the compound prism 407 formed of the wave plate 406, and is focused on the objective lens 108 or the disc 409.

In the two-beam spots focused on the disk, the leading focused beam 410 is the recording beam and the trailing focused beam 411 is the recording state confirmation beam.

In this conventional two-beam system, a difference signal between an analog signal obtained by delaying a recording signal for a fixed time or a digital signal obtained by delaying a fixed time and a signal obtained from a subsequent beam or an exclusive logic signal. When the sum (exclusive OR) is "0", the recording state can be confirmed by confirming that they are the same signal.

Further, a servo error signal which is a tracking error signal and a focus error signal is obtained by either one of the two focused beams focused on the disk. In FIG. 4, the specific configuration of servo error signal detection and signal detection is omitted.

[0012]

However, the above-mentioned conventional optical head has the following problems.

The first problem is that in the two-beam type optical head, the two beams themselves are expensive.

A second problem is that a two-beam laser is used to construct an optical head having a two-beam structure,
In the case of using two lasers having different wavelengths to combine the two beams to form a recording beam and a reproducing beam, the configuration of the optical system becomes complicated.

The third problem is that it is difficult to adjust the optical axis for landing two beams on the same track.

Further, as a fourth problem, there is a problem that the optical axis shifts due to a temperature change after the bending angle of the arrangement of the two beams is adjusted.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide an optical head capable of surely confirming a recording state by using a single laser. is there.

[0018]

In order to achieve the above object, the present invention is an optical head device capable of confirming a recording state at the time of recording with a single laser. And two light sensors for differentially detecting the reflected light from the optical disc are arranged at substantially the same position on the optical path system, and the recording at the time of recording is performed based on the differential detection signal output from these optical sensors. An optical head device capable of confirming a recording state at the time of recording, which is characterized by detecting a completed signal.

The present invention is preferably characterized in that the latch means is triggered by the rising and falling edges of the differential detection signal to detect a recorded signal at the time of recording.

Further, according to the present invention, in the phase change type optical head, a signal detecting the reflected light from the surface of the compound prism for performing beam shaping of the light emitted from the laser and a signal detecting the reflected light from the optical disk. The recorded signal at the time of recording is detected from the difference signal between the both.

Further, according to the present invention, in the magneto-optical head, a signal obtained by detecting the surface reflected light of the compound prism for performing beam shaping of the emitted light from the laser and the magneto-optical detected from the reflected light from the optical disk. The recorded signal at the time of recording is detected from the difference signal between the signal and the signal.

Based on the above configuration, the present invention is based on the principle of detecting the difference between the light emitted from the laser and the signal reproduction signal at the time of recording, and detecting the time difference from the light → thermal reaction process at the time of recording at the time of recording. It is possible to confirm the recorded signal.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

In the first embodiment of the present invention, as to the phase change optical head, as shown in the optical configuration of FIG.
In order to detect differentially the optical signal of the laser emission light from the laser 101 at the time of recording reflected on the surface of the compound prism 107 for beam shaping and the reflected light from the optical disk 109. The recording state is confirmed from the differential output of the differential amplifier 118 of the outputs of the two optical sensors 115 and 112 for detecting these signals. In order to match the differential amplifier 118 and the two optical sensors 112 and 115, the optical path system is configured to have the two optical sensors 112 and 115 at the same position.

Then, the compound prism 10 for emitting laser light
The signal detected from the surface reflected light at 7 and the optical disc 109
By triggering a latch circuit such as a D-type flip-flop by a rising edge and a falling edge of both differential outputs of the signal detected from the reflected light from the signal, the recorded signal at the time of recording is detected. Composed.

Further, in the second embodiment of the present invention, as for the magneto-optical head, as shown in the optical configuration of FIG. 2, a composite prism for performing beam shaping of the light emitted from the laser 201. A signal detecting the surface reflected light of 207, a signal detecting the reflected light from the optical disc,
The differential amplifier 218 detects the recorded signal at the time of recording from the differential output. In order to detect the magneto-optical signal, the half-wave plate 220 and the quarter-wave plate 221 are transmitted, and the polarization beam splitters 223 and 45 are transmitted.
Of the beam output split into P and S waves by the angle mirror 225 from the differential output of the differential amplifier 226.
Signal).

[0027]

EXAMPLES Examples of the present invention will be described below in order to explain the above-described embodiments of the present invention in more detail. First, an embodiment of the phase change optical head shown in FIG. 1 will be described.
In this embodiment, the light emitted from the laser 101 and the optical disc 1 are used.
The reflected light from 09 is differentially detected to confirm the recording state.

More specifically, referring to FIG.
The light emitted from 01 is collimated by the collimator lens 102, passes through the beam shaping prism 103, the polarization beam splitter 104, the 45-degree mirror 105, and the compound prism 107 including the quarter-wave plate 106, and the objective lens 108.
At that time, it is focused on the disc 109.

The reflected light from the disk 109 returns to the quarter-wave plate 106, the 45-degree mirror 105, and the polarization beam splitter 104 in the reverse order, and is 9 with respect to the polarization direction of the emitted light.
It becomes an S wave rotated by 0 degrees. The polarized beam is deflected by 90 degrees by the polarizing beam splitter 104 and goes straight through the half mirror 110. This straight light travels to an optical system (not shown) that is provided for detecting the servo signals of the focus error signal and the tracking error signal.

The beam deflected by 90 degrees by the half mirror 110 passes through the focusing lens 111 and is received by the optical sensor 112 for signal detection to obtain a reproduction signal (electrical signal).

The surface-reflected beam from the first beam incident surface of the compound prism 107 is a collimated beam, is deflected by the mirror 113, is condensed through the focusing lens 114, and is emitted directly from the laser 101. Sensor 115
To detect. The detection output of the optical sensor 115 is branched through the variable gain amplifier 116, and the amplifier 117
Is supplied to the laser drive circuit 100 via the optical power control circuit 100 and controls the power during laser reproduction, overwrite, or recording to be constant.
control loop (APC).

On the other hand, a signal output 115 'in which the signal from the beam emitted from the laser 101 is adjusted in an adjustable state by an amplifier and a signal output 112' from the polarization beam splitter 104 are subtracted (differential amplifier) 118. Subtract with
A confirmation (confirmation) signal is output from the differential amplifier 118, and this confirmation signal confirms the recording signal at the time of recording by signal processing described later.

Further, this polarization beam splitter 10
From the signal output 112 ′ obtained by photoelectrically converting the optical signal from the optical sensor 112 by the optical sensor 112, a signal output (RF signal) at the time of reproduction is obtained via the amplifier 119.

An embodiment of the magneto-optical head according to the present invention will be described below with reference to FIG. In this embodiment, the state of magneto-optical recording is confirmed from the light emitted from the laser 201 and the light reflected from the optical disk 209.

To detect a magneto-optical signal, the optical disk 2
The reflected light from the light beam 09 is transmitted through the half-wave plate 220 and the quarter-wave plate 221, and the polarization beam splitters 223 and 45 are transmitted.
A signal obtained by photoelectrically converting a beam output, which is split into P wave and S wave by the degree mirror 225, by the optical sensors 227 and 228, is passed through the differential amplifier 226 and a magneto-optical reproduction signal (RF signal).
Is configured to ask for.

Regarding the signal detection of the magneto-optical head, in order to confirm the recording state at the time of recording, it is necessary to compare the recording signal of the laser with the reproduction signal from the disk at the time of recording.

The light emitted from the laser 201, collimated by the collimator lens 202, becomes parallel light, and the surface reflected light of the beam shaping portion 203 of the compound prism 207 is reflected by the mirror 213, and the signal detected by the optical sensor 215 by the focusing lens 214 is amplified. A signal obtained through an amplifier (variable gain amplifier) 216 whose rate is variable and a reproduction signal from a disc are differentially detected by a differential amplifier 218, and recording state confirmation information at the time of recording is performed by signal processing described later. To get

Then, the surface reflected light of the compound prism 207 emitted from the laser 201 is photoelectrically converted by the optical sensor 215 and is fed back to the laser drive circuit 200 as an automatic optical power control loop.

FIG. 3 is a timing waveform diagram for explaining the signal processing of the embodiment of the present invention having the above-mentioned configuration.

Referring to FIG. 3, for the phase change optical head, the waveform 30 of the current signal of the laser recording amplifier (WAM) is used.
On the basis of 1, the signal 302 obtained by detecting the surface reflected light of the composite prism that performs the beam shaping by the light emitted from the laser is basically the same.

A signal (reproduction signal) 30 obtained by detecting the reflected light from the optical disc at the time of recording based on the recording signal 302.
In No. 3, since the reflectance is reduced in the recorded mark, the waveform at the time of recording is the signal 303 modulated by this recorded mark.

Therefore, a signal 304, which is a differential output of both the WAM signal 302 (equivalent to the laser emission light signal 302) and the signal 303 modulated by the recording mark, is obtained.

The rising edge and the falling edge of the signal 304 trigger the D-type flip-flop to detect the signal 305 of the recording mark itself modulated by the recording mark at the time of recording.

By this signal processing, the recording status signal can be confirmed at the time of recording.

Regarding the magneto-optical head, the modulation signal of the recording mark of the phase change medium described above is obtained from the reproduction signal shown in FIG. 2, and similarly, the recording state signal can be confirmed at the time of recording.

[0046]

As described above, according to the present invention,
Recording confirmation can be performed with a simple optical configuration without using a two-beam configuration, and there are advantages that the price of the optical head device is reduced and the operability and convenience of, for example, an optical disc device are significantly improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a phase change optical head according to a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a magneto-optical head according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a signal waveform for confirming a recorded signal during recording in the example of the present invention.

FIG. 4 is a diagram showing an optical configuration of a conventional optical head.

[Explanation of symbols]

 100 Laser Driving Circuit 101 Laser 102 Collimator Lens 103 Beam Shaping Prism 104 Polarizing Beam Splitter 105 45-degree Mirror 106 ¼ Wave Plate 107 Composite Prism 108 Objective Lens 109 Disk 110 Half Mirror 111 Focusing Lens 112 Optical Sensor 113 Mirror 114 Focusing Lens 115 Detection output 116 Gain variable amplifier 117, 119 Amplifier 201 Laser 202 Collimator lens 203 Beam shaping part 207 Composite prism 213 Mirror 214 Converging lens 215 Optical sensor 216 Amplifier with variable amplification rate 218 Differential amplifier 220 1/2 wavelength plate 221 1 / 4 Wave plate 223 Polarization beam splitter 225 45 degree mirror 226 Differential amplifier 227, 228 Optical sensor 301 (WAM) waveform 3 2 Signal detected surface reflected light 303 Signal from disc 304 Signal obtained differential output 305 Signal of recording mark 401 401 Two beam laser 402 Collimator lens 403 Beam shaping prism 404 Polarizing beam splitter 405 45 degree mirror 406 1/4 Wave plate 407 Compound prism 408 Objective lens 409 Disk 410 Leading focused beam 411 Trailing focused beam

Claims (6)

[Claims] 1. An optical head device capable of confirming a recording state at the time of recording with a single laser, for differentially detecting a light emitted from a laser at the time of recording and a reflected light from an optical disk. The two optical sensors are arranged at substantially the same position on the optical path system, and the recorded signal at the time of recording is detected based on the differential detection signal of the output of these optical sensors. Optical head device that can be checked. 2. The recording state confirmation at the time of recording according to claim 1, wherein the latch means is triggered by rising and falling of the differential detection signal to detect a recorded signal at the time of recording. Possible optical head device. 3. A phase-change type optical head, wherein both of a signal detecting surface reflected light of a compound prism for performing beam shaping of light emitted from the laser and a signal detecting reflected light from the optical disk are used. The optical head device according to claim 1, wherein a recorded signal at the time of recording is detected from the difference signal. 4. In a magneto-optical head, the difference between a signal detected from the surface reflected light of a compound prism for beam-forming the emitted light from the laser and a magneto-optical signal detected from the reflected light from the optical disk. From the signal,
The optical head device according to claim 1 or 2, wherein a recorded signal at the time of recording is detected. 5. A collimator beam is incident on a beam shaping prism portion, surface reflected light is deflected by a mirror, and return light from the optical disk intersects with a detection beam to form an optical path system. An optical head device that allows you to check the recording status during recording. 6. Light emitted from a laser during recording and light reflected from a recording medium are detected by optical sensors arranged in parallel on an optical path system, and a rise of a difference signal between outputs of these optical sensors is detected. An optical head device, which is configured to detect a recorded signal at the time of recording by a fall.