JPH0690796B2 - Optical information recording device and track interval measuring device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording apparatus, and in particular, two recording signal tracks are formed by simultaneously recording different signals on a recording medium using two recording beams. The present invention relates to a recording device and a measuring device for measuring the distance between two types of recording signal tracks formed by recording.

BACKGROUND ART As an example of forming two kinds of recording signal tracks by simultaneously recording different signals using two recording beams, preformat information of a guide groove recording type optical disk called a so-called land recording method is recorded. A case will be described as an example.

Conventionally, as a recording device in a mastering process of a guide groove recording type optical disc using two recording beams,
The one shown in FIG. 6 is known. In the figure, a laser beam emitted from a recording laser light source 1 is divided into two by a beam splitter 2, one of the divided beams is directly incident on a light modulator 3, and the other beam is reflected by a mirror 4. It is incident on the optical modulator 5. The optical modulators 3 and 5 perform optical modulation on the incident beams according to input signals. The beam optically modulated by the optical modulator 3 is reflected by the movable mirror 6 and is combined with the beam optically modulated by the optical modulator 5 by the movable half mirror 7 into one beam, and then the mirror 8 is formed.
And, as two beam spots with a minute interval, they are guided to a recording lens 10 by a mirror 9 via beam shaping lenses 18 and 19, and are recorded on a recording surface of a recording medium 11 such as a glass master disk coated with a photoresist or the like by the recording lens 10. It is collected at the same time.

In such a configuration, for example, the optical modulator 3 performs optical modulation according to the pre-pit signal, and the optical modulator 5 performs optical modulation according to the guide groove signal.
The focus position of two recording beams, that is, each beam of two recording beams, is adjusted by mechanically adjusting one or both tilts of 6, 7 so that the pre-pit is positioned between the guide grooves. By setting the spot interval, a preformat pattern as shown in FIG. 2 can be obtained.

FIG. 7 shows another conventional device. This device also has substantially the same configuration as the device shown in FIG. 6, except that fixed mirrors are used as the mirror 6 and the half mirror 7, and these mirrors 6, 7 and the optical modulators 3, 5 are The point is that the beam shaping lenses 12 and 13 and the fixed (or semi-fixed) beam shaping lenses 14 and 15 that are movable in a plane perpendicular to the optical axis of the beam are inserted between. In this conventional apparatus, the beam shaping lenses 12 and 13 are mechanically moved parallel to each other in a plane perpendicular to the optical axis of the beam so that two prepits are located between the guide grooves. The focus position of the recording beam is set.

As described above, all of the conventional apparatuses have a configuration in which the focusing positions of the two recording beams are mechanically adjusted, and thus the positioning accuracy and reproducibility are not so good.

The actual relative positional relationship between the recorded pre-pits and the guide groove is inspected and measured using an optical microscope, electron microscope, etc., and if it deviates from the target value, the mechanical adjustment described above is performed. Although the desired positional relationship was repeatedly obtained, it is difficult to measure the relative positional relationship with the required accuracy and resolution even with an optical microscope or an electron microscope. Further, when an electron microscope is used, destructive inspection is required. Therefore, there is a drawback that the recording medium becomes unusable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical information recording apparatus capable of setting the condensing positions of two recording beams with high accuracy and good reproducibility.

A further object of the present invention is to provide a track interval measuring device capable of highly accurately measuring the interval between two types of recording signal tracks that have been recorded and formed in a usable recording medium.

The optical information recording apparatus according to the present invention is an apparatus for recording and forming two kinds of recording signal tracks on a recording medium by two recording beams so as to be arranged in parallel and alternately in a track orthogonal direction. An optical deflecting means is provided in at least one optical path of the two recording beams, and the optical deflecting means adjusts the relative position of each beam spot on the recording medium in the track orthogonal direction by the two recording beams. There is.

Further, the track spacing measuring apparatus according to the present invention is one of two recording signal tracks of two types which are recorded and formed on the recording medium by two recording beams so as to be arranged in parallel to each other and alternately in the track orthogonal direction. Irradiating the recording surface of the recording medium with a measuring beam spot having a spot diameter that spans over the tracks, and based on the beam passing through the recording surface of the recording medium based on the measuring beam spot, the measuring beam spot with respect to the center line between two tracks is measured. The configuration is such that an error signal having a polarity and level according to the direction of deviation and the amount of deviation is generated, and the polarity and level of the DC component of this error signal are derived as the spacing information of the two types of recording signal tracks.

Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an optical information recording apparatus according to the present invention. In the figure, a laser beam emitted from a recording laser light source 1 is divided into two by a beam splitter 2, and one of the divided beams is a direct optical modulator 3
Incident on the light is modulated according to the pre-pit signal,
The other beam enters the optical modulator 5 after being reflected by the mirror 4 and is optically modulated by, for example, a guide groove signal. Light modulator
The beams optically modulated by 3 and 5 enter the optical deflectors 16 and 17, respectively.

The optical deflectors 16 and 17 have the function of changing the traveling direction of the incident beam.The optical deflectors 16 and 17 form a periodic change in the refractive index due to the ultrasonic waves in the substance and change the frequency of the ultrasonic waves. The one that uses the acousto-optic (A / O) effect that changes the diffraction angle of the beam, or the one that uses the electro-optic (E / O) effect that uses the change in the refractive index of the substance due to the applied electric field is used.

The beam deflected by the optical deflector 16 is reflected by the mirror 6,
In the half mirror 7, the beam deflected by the optical deflector 17 and one beam are combined, and then the beam is guided to the recording lens 10 by the mirror 9 via the mirror 8 and the beam shaping lenses 18 and 19, and is recorded by the recording lens 10. Two beam spots with minute intervals are simultaneously focused on the recording surface of a recording medium 11 such as a glass master coated with a photoresist or the like.

In such a configuration, in order to arbitrarily set the relative positional relationship between the two beam spots on the recording surface of the recording medium 11, that is, the interval, a slight change in the deflection angle of the beam by the optical deflectors 16 and 17 is used. The beam shaping lenses 18 and 19 are for adjusting the size of the cross section of the beam incident on the recording lens 10. According to this configuration, by electrically controlling one or both of the optical deflectors 16 and 17 (frequency, voltage, etc.), the distance between the two beam spots on the recording surface of the recording medium 11 can be accurately adjusted. You can set it with good reproducibility. With these two beam spots, a preformat pattern as shown in FIG. 2 can be obtained. In FIG. 2, 21 is a pre-pit recorded by using one recording beam, 22 is a guide groove recorded by using the other recording beam, and 23 is a land portion.

Next, the measurement of the relative positional relationship between the recorded pre-pits 21 and the guide grooves 22, that is, the interval will be described. This measurement is performed by the measuring device shown in FIG. 3, and a generally well-known reproducing device can be used as this measuring device.

In FIG. 3, a laser beam emitted from a laser light source 31 passes through a beam splitter 33 through an expansion optical system 32, and an objective lens 34 records a recording master (or a copy thereof) 35 produced by the recording apparatus of FIG. As shown in FIG. 4, it is focused on the recording surface as a beam spot S having a spot diameter extending over the two guide grooves 22, 22. It is assumed that the recording master (or a copy thereof) 35 is subjected to a treatment such as a metal reflection film attachment, if necessary. The reflected beam from the irradiation beam spot S is reflected by the beam splitter 33, part of which passes through the beam splitter 36, enters the photodetector 38 through the optical system 37, and the rest is reflected by the beam splitter 36 and passes through the optical system 39. It is incident on the photodetector 40.

The optical system 37 and the photodetector 38 are for focus control and reproduction signal detection, and the optical system 39 and the photodetector 40 are for tracking control using, for example, the push-pull method as an error generation method. In the push-pull method, as shown in FIG.
As the photodetector 40, a two-divided detector arranged so that the division lines coincide with the track tangential direction is used.
The push-pull signal, which is the difference in the amount of light received by both detectors obtained by the differential amplifier 51, can be derived as a tracking error signal.

In the track spacing measuring apparatus using the reproducing apparatus having such a configuration, if the push-pull signal is observed with the focus servo applied and the tracking servo closed, the relative positional relationship (interval) between the pre-pit 21 and the guide groove 22.
Can know. FIG. 4 shows an example of measurement. FIG. 4 (a) shows the waveform of the push-pull (PP) signal when the pre-pit 21 is located offset from the center between the guide grooves 22,22. In this case, in the section where the prepit 21 exists, a DC voltage having a polarity and a level corresponding to the deviation direction and the deviation amount with respect to the center between the guide grooves 22, 22 of the prepit 21 is generated as an offset. FIG. 4B shows the waveform of the bush pull signal when the pre-pit 21 is located in the center between the guide grooves 22 and 22, and in this case, no offset is observed.

Here, if the relative relationship (interval) between the prepit 21 and the guide groove 22 and the polarity and level of the offset, which is the DC component of the push-pull (PP) signal, are quantitatively investigated beforehand, The relative positional relationship (interval) between the prepit 21 and the guide groove 22 can be obtained from the DC component of the push-pull signal.

In this way, the relative positional relationship (interval) between the prepit 21 and the guide groove 22 is obtained from the DC component of the push-pull signal,
In order to eliminate the occurrence of offset in the push-pull signal, the optical deflectors 16 and 17 are used in the recording apparatus of FIG.
By adjusting the condensing position of the two recording beams (the interval between the two beam spots), it is possible to realize highly reliable adjustment of the converging position. As shown in FIG. It can be located in the middle of 22.

As described above, in the optical recording apparatus according to the present invention, the optical deflector is provided in the optical path of at least one of the two recording beams, and the recording medium by the two recording beams is provided by the optical deflector. Since the relative positions of the above beam spots in the direction orthogonal to the track are adjusted, the focus positions of the two recording beams can be set with high accuracy and reproducibility as compared with the conventional mechanical adjustment. it can.

Further, in the track spacing measuring device according to the present invention,
A recording beam of a recording medium is irradiated with a measurement beam spot having a spot diameter across one of two recording signal tracks, and measurement is performed based on the beam that has passed through the recording surface of the recording medium based on the measurement beam spot. Beam spot 2
A configuration is provided in which an error signal having a polarity and a level corresponding to a deviation direction and an amount of deviation with respect to a center line between tracks of a book is generated, and a polarity and a level of a DC component of the error signal are derived as distance information of two kinds of recording signal tracks. Therefore, the distance between the two types of recording signal tracks formed by recording can be measured with high accuracy without damaging the recording medium.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an optical information recording apparatus according to the present invention, FIG. 2 is a diagram showing a relative positional relationship between recorded pre-pits and guide grooves, and FIG. 3 is a track according to the present invention. Block diagram showing an embodiment of the interval measuring device,
FIG. 4 is a diagram showing the correspondence between the relative positional relationship between the prepits and the guide grooves and the push-pull signal waveform, and FIG. 5 is a configuration diagram showing the concept of error generation by the push-pull method, FIGS. 6 and 7. FIG. 7 is a block diagram showing a conventional example of an information recording device. Explanation of symbols of main parts 1 ... laser light source for recording 2 ... beam splitter 3, 5 ... optical modulator, 7 ... half mirror 11 ... recording medium, 16, 17 ... optical deflector 18, 19 ... … Beam shaping lens 21 …… Pre-pit, 22 …… Guide groove 23 …… Land

Claims (3)

[Claims] 1. A recording medium is formed by two recording beams.
What is claimed is: 1. An optical information recording device for recording and forming recording signal tracks of a kind so as to be arranged in parallel and alternately in a track orthogonal direction, wherein an optical deflecting means is provided in an optical path of at least one of the two recording beams. An optical information recording apparatus characterized in that the relative position of each beam spot on the recording medium by the two recording beams in the direction orthogonal to the track is adjusted by the light deflecting means. 2. The optical information recording apparatus according to claim 1, wherein the optical deflector is an optical deflector utilizing an acousto-optic effect or an electro-optic effect. 3. A measuring device for measuring an interval between two kinds of recording signal tracks formed by recording by two recording beams so as to be arranged in parallel to each other on a recording medium and alternately in a track orthogonal direction. An irradiation system for irradiating the recording surface of the recording medium with a measurement beam spot having a spot diameter extending over two tracks of one of the two kinds of recording signal tracks, and a recording surface of the recording medium based on the measurement beam spot. A light receiving system for receiving the beam that has passed through, and the measurement beam spot of
An error signal generating means for generating an error signal having a polarity and a level corresponding to the deviation direction and the amount of deviation with respect to the center line between the tracks of the book, and the polarity and level of the DC component of the error signal are the two kinds of recording signal tracks. A track-spacing measuring device, wherein the track-spacing information is derived as space information.