JPH01134728A - System for recording and reading for optical disk device - Google Patents

Abstract

PURPOSE:To increase a recording density and simultaneously, to improve reading speed by providing tracks for recording which have a pair at an interval narrower than a bit width, irradiating the middle of the tracks for recording by means of a light beam spot for reading larger than the interval, and reading the bit. CONSTITUTION:Two guides Tn1 and Tn2 for recording adjoining at the interval of the width of a light beam spot 5 for reading or below are provided to be made into a pair, bits 2, 3 and 4 are prepared on the recording guides Tn1 and Tn2 at the time of recording, and the light beam spot 5 for reading is projected to the middle of a pair of the recording guides Tn1 and Tn2 at the time of reading. The interval of two guides Tn1 and Tn2 for recording can be arranged at the degree of 1.6mum, and thus, a guide density for recording can be increased, and the recording density can be increased. By projecting the light beam spot 5 for reading to a point between the two guides Tn1 and Tn2 for recording made into a track pair, data on two tracks can be read by one beam at one time, and consequently, the reading speed can be increased.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a recording/reading method for an optical disc device.

[Conventional technology]

In the recording/reading method of conventional optical disk devices, recording pits are formed on recording tracks that are formed concentrically or spirally at extremely wide intervals, approximately 1.5 times the width of the recording pits, and at equal intervals. The idea was to record it by doing so.

Further, the reading method was to perform reading by irradiating a reading light beam spot onto the recording pit along the track.

FIG. 3 is a plan view of a main part of an optical disc used in an example of a recording/reading method of a conventional optical disc device.

As shown in FIG. 4, an optical disc 1. A recording guide is provided above so that recording tracks T are formed at regular intervals with a track interval of 1t.

[Problem that the invention seeks to solve]

In the recording/reading system of the conventional optical disk device described above, there is a restriction on the track spacing in order to reduce crosstalk between adjacent tracks, and therefore the recording density is also subject to this restriction. Furthermore, since the pits are read out for each track using one beam, there is a drawback that the readout speed is slower than in the multi-beam multi-track readout system.

An object of the present invention is to provide a recording/reading method for an optical disc device that has a high recording density and a fast reading speed.

[Means for solving problems]

The recording/reading method of the optical disc device of the present invention is an optical disc device in which two adjacent recording guides are provided as a pair with an interval equal to or less than the reading light beam spot width, and one pair of the recording guides is regarded as one track. The apparatus is configured to form pits on the recording guide during recording, and to irradiate the successive light beam spot to the middle of the pair of recording guides during reading.

[Effect]

In the present invention, two recording guides adjacent to each other with an interval equal to or less than the recording pit width are formed into a pair, and the interval between the two recording guides on the adjacent sides of the two adjacent pairs is set to 1.6 mm, which is the same as before.
They can be arranged on the order of μm, thereby increasing the recording guide density, and thus making it possible to increase the recording density. In addition, by irradiating the successive light beam spot between two recording guides forming a track pair, it is possible to read data on two tracks at a time with one beam, thus increasing the readout speed. It is possible to increase it.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a main part of an optical disc showing the state of pits recorded using an embodiment of the present invention.

As shown in FIG. 1, the recording area of the optical disc 1 includes pairs of recording tracks T1□, T1□ to TI.

TI2~'rn1. Tn2 (n is a positive integer, i is 1≦i
≦n integer) is formed by a track interval I22 between each pair of recording tracks, and a track interval 11 between each adjacent pair of recording tracks.

Here, when el>e2, the track spacing 22 is narrower than the recording pit width, and the track spacing e1 is the same as in the prior art described above.

On the paired recording tracks T+□ and T12, there is a pip)-
Pit 2, 3, and 4 are recorded, but pits 2 to 4 are recorded as read-only at the time of manufacture, such as on video discs and CDs, on a recording guide that is preformed at the time of disc manufacture. Alternatively, recording is performed by controlling the head position on the recording guide and irradiating the recording guide with light emitted from the head.

Also, a pair of recording tracks T+1. The pits on the TI□ are read out using the readout light beam spot 5. The readout light beam spot 5 has a size equal to the track interval I22.
The recording track T...7.2
two recording tracks T-th forming a pair by irradiating the middle of the
The pits on T and 2 can be irradiated at the same time.

In the recording guide arrangement corresponding to the recording track T, T, 2, a pair of guides is formed, and during reading, the reading light beam spot 5 is irradiated to the middle of the two guides forming the pair of guides.

FIGS. 2(a) to 2(d) are plan views of essential parts of an optical disc showing the correlation between pits, successive light beam spots, and light receiving patterns when reading out the pits shown in FIG. 1, respectively. Note that in FIG. 2, the shaded portions of the light receiving pattern of the reflected light that irradiates the light receiving portion indicate dark portions.

As shown in FIG. 2(a), pit 2 is located on recording track T1. When it is above, the left half of the light receiving pattern 5a reflected from the optical disk 1 of the successive light beam spot 5 becomes dark.

Similarly, when reading pit 3 on recording track T12 in FIG. 2(b), FIG. 2(c) reads pit 4 recorded across recording tracks T,... Light receiving patterns 5b and 5° in the case of reading are shown, respectively.

Further, FIG. 2(d) shows the light reception pattern 5. when irradiating onto a recording track without pits. shows.

In this way, the recording tracks T1□ form a pair.

By irradiating the successive beam spot 5 in the middle of TI2, the expected difference in pits is detected as a difference in the light receiving pattern, and the pits are read out.

In FIG. 2(a), the right half of the readout light beam spot 5 is affected by the diffraction caused by the track groove, so the right side of the light receiving section is significantly brighter than the left side. On the other hand, in FIG. 2(b), the position of the pit 3 is opposite to that in FIG. 2(a), so the light receiving pattern 5
The bright and dark areas in b are the light receiving pattern 5.b shown in FIG. 1(a). The opposite is true. Furthermore, in FIG. 2(C), since the reading light beam spot 5 is completely contained within the pit 4, the light receiving pattern 5° becomes a dark pattern as a whole. Figure 2(d)
In this case, the reading light beam spot 5 is affected by the diffraction caused by the two track grooves, and the entire light receiving pattern 5d becomes bright.

As a result, by detecting the difference in pits as a difference in the light receiving pattern, one reading light beam spot can detect two
It becomes possible to avoid reading pits on the recording track of a book.

Therefore, the track spacing e2 is 172 of the track spacing e1.
In this case, the track density can be increased by 4/3 compared to the conventional case shown in FIG. 3 described above. Furthermore, since two recording tracks are read at once, the successive output speed can be twice that of the conventional system.

〔Effect of the invention〕

As explained above, the present invention provides a method for reading out pits by providing a pair of recording tracks with an interval narrower than the pit width and illuminating the middle of the pair of recording tracks with a readout light beam spot larger than the interval. This has the effect of increasing the recording density and improving the read speed compared to the conventional method.

2(a) to (d) are plan views of main parts of the disk showing the state of the disk.
41 is a plan view of the main part of an optical disk showing the correlation between the pit, the readout light beam spot, and the light receiving pattern when reading the pits, and FIG. 3 is used for an example of the recording/reading method of a conventional optical disk device. FIG. 2 is a plan view of essential parts of an optical disc.

1.13... Optical disc, 2.3.4... Pit,
5... Light beam spot for continuous output, 5a to 5d... Light receiving pattern, el, e2... Track interval, T, '
r11°T12~T,,,T,2~T 111 + T
f12: Recording track.

Claims (1)

[Claims] An optical disc device in which two adjacent recording guides are provided as a pair with an interval equal to or less than the reading light beam spot width, and one pair of the recording guides is regarded as one track, and pits are formed on the recording guides during recording. A recording/reading method for an optical disc device, characterized in that, during reading, the reading light beam spot is irradiated between the pair of recording guides.