JP2517898B2 - Optical recording method and apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical recording method and an apparatus used for optically recording information on a recording medium such as a magneto-optical disk.

[Conventional technology]

When a signal is recorded on a magneto-optical disk using a laser diode, the data transmission rate is limited due to the eccentricity of the disk and the like. In recent years, the amount of data to be recorded has increased dramatically, and if a large amount of data is to be recorded on one track, the disc must be rotated at a speed of several thousand revolutions / min or more.

As a countermeasure against this, a method has been proposed in which a recording head is composed of a plurality of laser diodes and recording is performed on a plurality of tracks of a disk by using a plurality of beams to achieve a high transmission rate. A pulse train recording method is used to record signals on multiple tracks. The pulse train recording is a recording method in which, for example, one writing pulse having a narrow width is provided for each "1" data within a period between the reference pulses, whereby heat generation of the laser diode can be suppressed. Since a plurality of laser diodes are used when recording on a multi-track, it is necessary to drive these laser diodes with a pulse having a narrow width to suppress the heat generation as much as possible.

[Problems to be solved by the invention]

As mentioned above, with multiple beams on the multi-track,
When pulse train recording is performed, for example, when the signals of all tracks are “1”, beams are simultaneously generated from all the laser diodes, so that even if a narrow pulse is used, the generation is considerably large. Therefore, the package housing the laser diode is heated, and in the worst case, the laser diode can be destroyed.

[Means for solving problems]

A plurality of light sources for emitting a plurality of beams, a timing control means for controlling the plurality of light sources so that they can be sequentially turned on within a period between predetermined reference pulses, and an output signal and information from the timing control means. And driving means for pulse-driving each of the plurality of light sources, and recording means for recording the information on a plurality of tracks on a recording medium based on the beams emitted from the plurality of light sources. Since the plurality of laser diodes do not emit light at the same time, heat generation of the recording head can be reduced and crosstalk between tracks can be reduced.

〔Example〕

Shows an embodiment in principle of Fig. 1 according to the present invention, four tracks TR _1, TR _2, TR _3, "1" to the TR _4, the data D ₁ of the "0", D _2, D ₃ , D ₄ is recorded.

t ₀ , t ₁ , t ₂ ... indicate time slots, and data is optically recorded in synchronization with each time slot. In this embodiment, the timings of the write pulses P ₁ , P ₂ , P ₃ , P ₄ for pulse train recording the data on the tracks TR _{1 to} TR ₄ are shifted so as not to overlap each other.

In the case shown, in order to shift the pulses P _{1 to} P ₄ from each other,
P ₂ , P ₃ , and P ₄ are sequentially delayed with respect to P ₁ by τ ₁ , 2τ ₁ , 3τ ₁ . The pulse P ₁ is synchronized with the reference pulse REF synchronized with the time slot. Also, all the pulses P _{1 to} P ₄ are staggered with respect to each other in one time slot.

 FIG. 2 shows an embodiment of the recording circuit.

In FIG. 2, the serial data D ₀ shown in FIG. 3 is input to the 4-bit shift register 5 in synchronization with the clock pulse CK. This data D ₀ is latched by the latch pulse P _L , and 4-bit parallel data D ₁ , D ₂ , D ₃ , D ₄
Becomes These data D _{1 to} D ₄ are data recorded on the tracks TR _{1 to} TR ₄ in FIG. ₁ , respectively. These data D ₁ to D ₄ is applied to the AND gates 1, 2, 3, 4. The reference pulse REF output from the shift register 5 is added to the AND gate 1, and the pulse REF is supplied to the AND gate 2.
Pulse delayed by the delay circuit 6 is added. A pulse obtained by delaying the pulse REF by delay circuits 7 and 8 is applied to the AND gate 3. A pulse obtained by delaying the pulse REF by the delay circuits 9, 10 and 11 is added to the AND gate 4. The delay circuits 6 to 11 each have a delay time τ ₁ .

According to the above configuration, the write pulses P _{1 to} P _{4 of} FIG. 1 used for pulse train recording from the AND gates 1 to _4.
Are obtained respectively. These pulses P _{1 to} P ₄ are applied to the four laser diodes 18, 19, 20, 21 of the recording head 16 via the laser diode drive circuits 12, 13, 14, 15 to selectively select these laser diodes. Light up. The beams output from the laser diodes 18 to 21 are objective lenses.
Signals are optically recorded on four tracks of a magneto-optical disk 24 driven by a motor 23 via 22, respectively.

According to the above, in the tracks TR ₁ to TR ₄ , the pulses are not applied to the two or more tracks in an overlapping manner, so that the two or more laser diodes do not emit light at the same time. Heat generation can be further suppressed by train recording. At the same time, since the pit at the same time the four tracks TR ₁ to Tr ₄ on the disc is not formed, becomes clear identification of the signal between tracks during reproduction, it is possible to reduce crosstalk between tracks .

〔The invention's effect〕

When the signal is optically recorded on the multi-track by pulse train recording, heat generation of the recording head can be further suppressed as compared with the conventional pulse train recording. Further, it is possible to reduce crosstalk.

[Brief description of drawings]

FIG. 1 is a timing chart showing an embodiment of the present invention in principle, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG.
The figure is the timing chart of FIG. Reference numerals used in the drawings are 1 to 4 ... AND gate 5 ... Shift register 6-11 ... Delay circuit 20 ... Recording head 24 ... Magneto-optical disk.

Claims (2)

(57) [Claims] 1. A plurality of light sources for emitting a plurality of beams, a timing control means for controlling the plurality of light sources so that they can be sequentially turned on within a period between predetermined reference pulses, and an output from the timing control means. Drive means for pulse-driving each of the plurality of light sources according to signals and information, and recording means for recording the information on a plurality of tracks on a recording medium based on beams emitted from the plurality of light sources are provided. Recording device. 2. A recording method for optically recording information by pulse-driving beams from a light source onto a plurality of tracks on a recording medium, wherein a plurality of beams arranged according to the plurality of tracks have a predetermined reference pulse. A recording method characterized by controlling so as not to turn on at the same time within a period of time.