JPH04364226A - Optical information recording device - Google Patents

Abstract

PURPOSE:To provide an optical information recording device where a recording track is formed so that recording density becomes high at the time of recording plural information signals having correlation in an optical information recording medium with plural corresponding optical beams and the influence of noise owing to crosstalk at the time of reproduction becomes little. CONSTITUTION:A signal generating means which frequency-modulates and delays plural information signals having correlation, a light source 1 emitting plural optical beams, an optical modulation means 4 which modulates the optical beams by the information signals and an radiation means which polarizes the other optical beams against the optical beam becoming the inner reference of the modulated optical beams in the direction of the recording track and simultaneously irradiates the optical recording medium with the beams are included.

Description

[Detailed description of the invention]

0001

[Technical field] The present invention provides a method for transmitting a plurality of information signals to a plurality of optical beams.
The present invention relates to a recording device that records on an optical recording medium using a recording system.

0002

BACKGROUND OF THE INVENTION Recording devices that pulse-modulate each of a plurality of light beams using a plurality of information signals and record on an optical recording medium such as an optical disk have been developed in recent years and are being put into practical use. For example, a recording device is being put into practical use that divides a high-definition baseband signal into three channels, a luminance signal and two color difference signals, and records them on a set of three tracks on an optical disc.

In FIG. 8, a light beam P0 emitted from a laser light source 1 is reflected by a mirror 2 and formed into a half mirror.
3a. In the half mirror 3a, 1/3 of the amount of the incident light beam is transmitted and 2/3 is reflected. The transmitted light beam P1 is incident on the pulse modulator 4a. The reflected light beam is incident on the half mirror 3b, where half of it is transmitted and the other half is reflected. The reflected light beam P2 enters the pulse modulator 4b, and the transmitted light beam P3 is reflected by the mirror 3c and enters the pulse modulator 4.
It is incident on c. Therefore, the three light beams P1, P2,
The light amounts of P3 are equal to each other. The three pulse modulators 4 are so-called AOM (Acoustic Optical
This is an optical modulation means called a modulator, which modulates a light beam into a pulse signal using a supplied input signal.

On the other hand, as shown in FIG. 9, three video signals from a high-definition baseband signal source (not shown) include a luminance signal Y, a red difference signal R, and a blue difference signal B. The signal is a line sequential signal, and for example, each line signal Y1, Y2, Y3 of the luminance signal Y has a correlation with each other. These video signals are supplied to an FM modulator 5 as a signal generating means. FM modulators 5a, 5b,
Each of the modulated video signals from 5c is provided to a respective pulse modulator 4a, 4b, 4c. In the pulse modulator 4, each light beam S1, S2, S3 pulse-modulated by the video signals 1 to 3 is irradiated onto a recording medium by an irradiation means described below.

The light beam S1 is reflected by a mirror 6a and transmitted through beam splitters 6b and 6c. The pulse-modulated light beam S2 from the pulse modulator 4b is reflected by the beam splitter 6b and transmitted through the beam splitter 6c. Similarly, the light beam S3 from the pulse modulator 4c is reflected by the beam splitter 6c. These three light beams are reflected by a mirror 7, converged by an objective lens 8, and irradiated onto a glass master 9. The glass master disk 9 is rotationally driven by a spindle motor 10 at a constant linear velocity or angular velocity.

[0006] In the glass master disk 9, three light beams S
1, S2, and S3 form a set of three tracks, on which each video signal is recorded. During this recording, in order to increase the recording density, the irradiation positions of these light beams are arranged close to each other on the same line in the radial direction of the glass master disk 9. However, if the diameter of the light beam is not made sufficiently thin, the pit shape will be distorted due to the influence of adjacent light beams, and in severe cases, adjacent tracks will coalesce, as shown in Figure 10. There is a fear.

[0007]

OBJECTS OF THE INVENTION It is an object of the present invention to increase the recording density when recording a plurality of mutually correlated information signals on an optical information recording medium using a plurality of corresponding light beams, and to An object of the present invention is to provide an optical information recording device that forms recording tracks such that the influence of noise due to crosstalk is reduced in the case of.

[0008]

SUMMARY OF THE INVENTION An optical information recording apparatus according to the present invention includes: a signal generating means for generating a plurality of information signals that are correlated with each other; a light source that emits a plurality of light beams; a light modulation means for modulating each of a plurality of light beams; and a light modulation means for simultaneously irradiating the plurality of light beams obtained from the light modulation means onto an optical recording medium to send the information signal parallel to the recording medium. irradiation means for recording while forming a plurality of tracks, wherein the irradiation means is arranged to irradiate at least one irradiation position of the plurality of light beams on the recording medium with respect to another irradiation position of the plurality of light beams; The irradiation position of the light beam is shifted backward on the time axis of the track by a predetermined distance, and the signal generating means modulates each of the information signals modulating each of the other light beams. The structure includes a delay means for delaying the information signal modulating the light beam by a time corresponding to the time to record the predetermined distance.

[0009]

Effect of the Invention In the optical information recording device according to the present invention, the irradiation position of at least one of the plurality of light beams carrying a plurality of mutually correlated information signals is The irradiation positions of the light beams are each shifted backward on the time axis of the track by a predetermined distance, and each of the corresponding information signals is delayed and recorded by a time corresponding to the time to record the predetermined distance length.

0010

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 7. In FIG. 1, in addition to the FM modulator 5, a delay circuit 11 for delaying a video signal is provided as a signal generating means. This delay circuit 11 is composed of a delay element such as a CCD. In addition, the same reference numerals as those in FIG. 8 among the constituent elements in FIG. 1 represent the same constituent elements. Each of the video signals from the FM modulator 5 is delayed by a predetermined time in a delay circuit 11 according to a control signal from a controller 12, and then supplied to the pulse modulator 4.

As shown in FIG. 2, the delay time of each delayed video signal is different, and the delay time of video signal 2 is delayed by t1 with respect to the delay time of video signal 1. Also, the delay time of video signal 3 is the same as that of video signal 1.
It is delayed by t2 with respect to the delay time of . Therefore,
Each of the light beams that are pulse-modulated by the video signals in the pulse modulator 4 and irradiated onto the glass master disk 9 are also irradiated in accordance with the delay time. That is,
The light beam S2 is irradiated with a delay of t1 with respect to the light beam S1, and the light beam S3 is irradiated with a delay of t with respect to the light beam S1.
Irradiation is delayed by 2 seconds.

In FIG. 3, the irradiation position of the light beam S2 on the glass master disk 9 is shifted backward by d1 on the track time axis with respect to the irradiation position of the light beam S1. Similarly, the irradiation position of the light beam S3 is the irradiation position of the light beam S1.
d2 backward on the track time axis with respect to the irradiation position of
It is only biased. Furthermore, the rotating glass master 9
When the linear velocity at the irradiation position shown in the figure is v, the delay time of the delay circuit 11 is set by the control signal so as to satisfy the following relational expressions: d1 = v x t1 d2 = v x t2.

The linear velocity v is the so-called CLV (constant linear velocity)
In the case of a master disc, the linear velocity is always constant regardless of the irradiation position, but in the case of a so-called CAV (constant angular velocity) master disc, the linear velocity changes depending on the irradiation position in the radial direction. That is, if the angular velocity is ω and the radial position of the master is r, then the linear velocity v is v=ω
It is expressed as ×r. Therefore, in the case of a CLV master, the controller 12 issues a control signal that makes the delay time of the delay circuit 11 constant. On the other hand, in the case of a CAV master, the controller 12 detects the irradiation position in the radial direction and issues a control signal that changes the delay time of the delay circuit 11 in accordance with the detected position. Regarding the method of detecting the position in the radial direction, for example, Japanese Patent Application Laid-Open No. 2-2202
The method disclosed in Japanese Patent No. 77 is known.

Next, FIG. 2 shows the operation of the configuration shown in FIG.
This will be explained with reference to FIGS. When the video signal 1 shown in FIG. 2 is supplied from the delay circuit 11a to the pulse modulator 4a, as shown in FIG. Hereinafter, for convenience, this track will be abbreviated as Y1 track (the same applies to other line signals). continue
After a delay of t1, video signal 2 is supplied from delay circuit 11b to pulse modulator 4b, and Y
Formation of two tracks begins. The starting point of this Y2 track formation coincides with the starting point of the Y1 track in the track direction according to the relational expression d1 = v x t1. Subsequently, with a delay of t2 from the start of the Y1 track, the video signal 3 is supplied from the delay circuit 11c to the pulse modulator 4c, and the formation of the Y3 track is started by the light beam S3 as shown in FIG. The starting point of this Y3 track is also Y1 according to the relational expression d2 = v × t2.
The starting point of the track coincides with the position in the track direction. That is, the irradiation means according to the present invention positions the irradiation position of the light beam carrying the delayed signal behind the irradiation position of the light beam carrying the reference signal on the time axis of the track. The beam is irradiated at a distance corresponding to the product of the delay time and the recording linear velocity.

When each video signal delayed in this way is recorded simultaneously, Y1, Y2 and Y
The recording start points of the three tracks are formed on the same line in the radial direction of the glass master disk 9. Continued R
Similar results were obtained for tracks 1, R2, R3, B1, B2, B3, etc., and as shown in Figure 6, a set of three tracks with mutually correlated signals is formed in parallel. be done. The two outer tracks of the set of tracks are adjacent to the adjacent set of tracks, but the sets of tracks are also formed to have a correlation with each other. Alternatively, it is also possible to form tracks that have correlation only within the set of tracks by widening the track interval between the sets of tracks to such an extent that they are not affected by crosstalk.

When reproducing a video signal from an optical disk formed based on this glass master disk 9, three reading light beams are irradiated onto a set of three tracks on the optical disk. And those return light beams
Three read signals are obtained from the system. Although each return light beam is mixed with crosstalk from adjacent tracks, the influence on the reproduced signal can be reduced due to the correlation between the adjacent tracks.

In the above embodiment, the irradiation positions of the three light beams are diagonal, but in another embodiment, as shown in FIG. Similar results can be obtained with a delta-like position offset by d. In this case, the delay time of each delay circuit is determined by the deviation d and the linear velocity of rotation of the glass master.

Note that in the above embodiment, the delay circuit 11
is provided between the FM modulator 5 and the pulse modulator 4, but it may also be provided before the FM modulator 5. For example, in a high-definition baseband signal source (not shown),
It is also possible to utilize line memory such as FIFO. Furthermore, the information signals to be recorded are not limited to video signals.
Other information signals may be used as long as they are correlated signals.

[0019]

As explained above, in the optical information recording apparatus according to the present invention, at least one light beam serving as a reference among a plurality of light beams carrying a plurality of mutually correlated information signals is used. - The irradiation position of another light beam is shifted backward by a predetermined distance on the time axis of the track with respect to the irradiation position of the light beam, and the corresponding information signal is generated for a time corresponding to the time to record the predetermined distance. By delaying and recording each of these simultaneously, it is possible to increase the recording density and reduce the influence of noise due to crosstalk during reproduction.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of an optical information recording device according to the present invention.

FIG. 2 is a time chart of input signals supplied to the pulse modulator 4 in FIG. 1.

3 is a schematic diagram showing the irradiation position of the light beam on the glass master disk 9 in FIG. 1. FIG.

4 is a schematic diagram showing the irradiation position of the light beam on the glass master disk 9 in FIG. 1. FIG.

5 is a schematic diagram showing the irradiation position of the light beam on the glass master disk 9 in FIG. 1. FIG.

6 is a diagram of a set of tracks formed on the glass master disk 9 in FIG. 1. FIG.

FIG. 7 is a diagram of a set of tracks formed on a glass master disk 9 according to another embodiment.

FIG. 8 is a block diagram of a conventional optical information recording device.

9 is a time chart of input signals supplied to the pulse modulator 4 in FIG. 8. FIG.

FIG. 10 is a diagram of a set of tracks formed by a conventional optical information recording device.

[Explanation of symbols] 1...Laser light source 4...Pulse modulator 9...Glass master 11...Delay circuit

Claims (2)

[Claims] 1. Signal generating means for generating a plurality of information signals that are correlated with each other, a light source that emits a plurality of light beams, and each of the plurality of light beams being modulated by the plurality of information signals. and a plurality of light beams obtained from the light modulation means to simultaneously irradiate an optical recording medium to record the information signal while forming a plurality of parallel tracks on the recording medium. irradiation means, wherein the irradiation means sets an irradiation position of at least one of the plurality of light beams on the recording medium to an irradiation position of another light beam on the track. and the signal generating means is biased backward on the time axis by a predetermined distance, and the signal generating means
delay means for delaying each of the information signals modulating each of the other light beams by a time corresponding to the time for recording the predetermined distance length with respect to the information signal modulating the at least one light beam; An optical information recording device comprising: 2. The optical system according to claim 1, wherein the plurality of light beams are such that the irradiation positions of the light beams irradiated onto adjacent tracks have a predetermined interval in the direction of the track. Information recording device.