JPS6284441A - Recording and reproducing method for optical disk - Google Patents

Abstract

PURPOSE:To record and reproduce data at a high transfer rate by giving plural optical heads irradiating a laser beam on an optical disk and simultaneously or individually driving laser diodes in the optical head. CONSTITUTION:Two optical heads A and B can be simultaneously or individually driven, and an external controller controls traces on the track of laser beams and jumping between tracks. For instance, the laser beam of the head A repeats jumping between tracks at every half rotation, whereby the head A traces the track toward the outer periphery from 1 4 5 8 9 12... in this order. The head B tracks the track in the same manner from 2 3 6 7 10 11... in this order. Accordingly, when the optical heads A and B are simultaneously driven at the time of recording, two laser beams simultaneously trace the track while the optical disk makes one turn at a constant rate, whereby this can obtain a recording rate twice a case where a laser beam is individually driven.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for recording and reproducing high transfer rate data, such as a digitized video signal, onto an optical disc.

Conventional techniques Conventional methods include, for example, the literature Optical Engineering (OPTIC!AL ENGINEERI).
NG) July, August 1983. vol1
22. It is shown in /Pa4 and is 2 base; FIG. 6 shows the high transfer rate recording and reproducing method of the above-mentioned document. Digital data is sequentially recorded on concentric tracks using a single laser beam on an optical disk that rotates at a constant rotational speed, and is reproduced at once using eight laser beams during playback. Therefore, it is possible to reproduce data at a transfer rate eight times that of recording.

Problems to be Solved by the Invention However, with the above method, it is possible to achieve a high transfer rate only for reproduction. In order to make recording possible, a group of laser diodes (hereinafter referred to as a laser array) that can drive multiple tracks simultaneously with different signals is required. This laser array has a high power required for each laser diode to record a signal on a material (for example, when a thin film of TeOx is used as the recording material, about 20 m
A device using a W laser diode has been put into practical use), and this is difficult to achieve. Furthermore, there are three pages of problems in that a plurality of laser beams must be narrowed down and irradiated onto each track from the same optical system, making the optical system complicated.

In view of this point, an object of the present invention is to provide a recording and reproducing method that enables high transfer rate recording and reproducing.

Means for Solving the Problems The present invention has a plurality of optical heads that irradiate laser beams onto an optical disk, and has a configuration in which the laser diodes in each optical head can be driven simultaneously or individually, so that recording signals can be This is a method of time-sharing recording and reproducing according to predetermined rules.

Effect The present invention uses the method described above to simultaneously drive a plurality of optical heads to achieve high-transfer recording and reproduction, and to drive them individually to reduce the transfer rate. By changing the combination of optical heads, the transfer rate can be changed stepwise.

Embodiment FIG. 1 shows the order in which a laser beam is traced on an optical disk in a recording/reproducing method according to a first embodiment of the present invention. In FIG. 1, a disk with spiral grooves cut therein was used to make it easier to understand the effects of the present invention.

B shows the case with two optical heads.

A, B, the two optical heads can be driven simultaneously or individually, and an external controller controls the track tracing and inter-track jumping of the laser beam. For example, the laser beam of head A traces the track a - b (approximately one revolution!A) shown by 1 in Fig. 1, jumps to C at b, and moves to the l rack shown by 4. . Next, after tracing 4, at point d, e is directly traced without jumping, and track 5 is traced. In this way, by repeating the inter-track jump every half rotation, head A moves from 1 to 4 to 5.
→8→9→12-...Trace the trunk toward the outer periphery.

Head B is 1, similarly 2 → 3 → 6 → 7 → 1o → 11...
Trace in the order of... Therefore, if optical heads A and B are driven simultaneously during recording, 5 be! The two laser beams simultaneously trace the aforementioned tracks while the optical disk rotates once at a constant speed, resulting in a recording rate twice that of the case where the laser beams are driven individually. Furthermore, if the data recorded in this manner is simultaneously reproduced, recording and reproduction can be performed at twice the transfer rate.

The configuration of an optical disc recording and reproducing apparatus using the present embodiment described above will be briefly described. 1 is an optical head A consisting of a semiconductor laser, a PIN diode, and other optical components; 2 is an optical head B; 3 is an optical disk medium; 4 is a formant generation circuit for dividing data into two and recording it on the optical disk, a laser drive circuit, etc. 5 is a reproducing circuit that restores the signals reproduced from the two heads to the original signals. During recording, the signal input to the recording circuit 4 undergoes processing such as format generation, which will be described later.
It is divided into two parts, hA and ahB. The data of ohA is sent through optical head 1, and the data of ahB is sent to optical head 2.
The data is recorded on the optical disc medium 3 via. During reproduction, the signal is reproduced by the optical head A and the optical head 6B, and is converted into the original signal by the reproduction circuit 6. Note that in FIG. 2, a drive unit that rotates the optical disk, a mechanism that moves the optical head, and a control unit are omitted.

Next, a method will be described in which by using either optical head A or H, reproduction at a low transfer rate is possible with a single laser beam. FIG. 3 shows an example of signal processing of a recording circuit that makes this possible. Further, FIG. 4 shows a waveform diagram showing the operation. 6 to 9 are buffer memories 1 to 4, and the clock frequency during writing is f. , the clock frequency at the time of reading is %fo. The operation of the recording signal generating section configured as shown in FIG. 3 will be explained.

S shown at 60 in FIG. , Sl, S2. S3...
・Signal block sequence (for example, S is one of the video signals)
data for one field) is input to memories 1 to 4, and the data is input when the input gate signals indicated by 51 to 54 are "H".
” and is shown as 55.56.

R/W is written to each memory when the gate signal is "L". That is, S is stored in memory, 827 pages 7 is stored in memory 2, B3 is stored in memory 3, and B4 is stored in memory 4. On the other hand, when the R/W gate signal is H'', the above signal is read out and data is output to the output terminal of the memory.The above operation causes chA.

An output signal indicated by 57.58 is obtained at the ahB terminal.

With the above configuration, each part of the track of the optical disc-F shown in FIG. 1 includes 1, S4, B4, .・・・・・・、
2, B2, 3, B3... data is recorded. For example, if the spiral groove is tracked and traced only by head A, the signal train will be s1. s2. s3. s4... are played in order, and the transfer rate is % when both A and B are used. That is, the transfer rate can be selected in two stages.

In the above description, two heads A and B were used, but FIG. 5 shows a second embodiment having four heads A, B, C, and D. This can also be implemented according to the present invention in the same manner as the first example. In this case, a four times higher transfer rate will be obtained. However, as in the first embodiment, it is also possible to generate continuous recording signals even when reproduced by one head alone. Furthermore, if two of the four heads are used, the transfer rate can be reduced to 1%, which is the same transfer rate as in the first embodiment. The present invention can be practiced even if the grooves of the optical disk shown in FIGS. 1 and 6 are not spiral but concentric. In this case, the only difference from the above example is the jump control of the head.

Detailed explanation of the invention: According to the present invention, a high transfer rate is possible, and the transfer rate can be changed by combining a plurality of heads. However, by setting the rules for recording signals, it is possible to reproduce continuous signals with a single beam, and this has great practical effects.

[Brief explanation of drawings]

FIG. 1 is a laser beam trace diagram using two heads of a first embodiment of the present invention, FIG. 2 is a configuration diagram of an apparatus implementing the present invention, and FIG. 3 is a diagram showing two navels 9. A block diagram of generating a recording signal to the
Figure 5 is a laser beam trace diagram showing the second embodiment using four heads; Figure 6 is a diagram showing a high transfer rate reproduction method using a conventional laser array. It is a diagram. 1...Optical head A, 2...Optical head B, 3...Original disk medium, 4...
Recording circuit, 5...Reproduction circuit, 6-9...
・Memory circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure O Figure 4 Nu δ7 δ0 . 3t δ45δ −,
2δ, 3

Claims (1)

[Claims] This is a method for digitally recording and reproducing signals on an optical disk, which has N optical heads (N = 2, 3, etc.), and the light emitting elements in each optical head are activated simultaneously or individually. An optical disc recording and reproducing method characterized in that the optical disc can be driven and that a laser beam is independently controlled every 1/N rotation to jump between tracks and trace the tracks.