JPH01144220A - System for reading out record of optical disk device - Google Patents

Abstract

PURPOSE:To heighten recording density and to accelerate readout speed by providing recording tracks which form a pair with intervals smaller than bit width, and reading out a bit by projecting a reading optical beam spot with the interval larger than that of the track on the intermediate part of the pair of recording tracks. CONSTITUTION:In the recording area of an optical disk 1, the recording tracks T11, T12-Tn1, Tn2 which form the pairs are formed at the track interval l2 of the recording tracks which form the pair, respectively, and the track interval l1 of adjacent recording tracks which form the pair, and it is set as l1>l2. Also, the readout of a pit on the recording tracks T11 and T12 which form the pair is performed by a reading optical beam spot 5. The reading optical beam spot 5 is formed larger than the track interval l2, and projects the pits on the two recording tracks T11 and T12 which form the pair simultaneously by projecting the intermediate part of the recording tracks T11 and T12. In such a way, it is possible to heighten the recording density and to accelerate the readout speed.

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 recording pits with successive light beam spots along the track.

FIG. 6 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. 6, an optical disc 1. A recording guide is provided above so that recording tracks T are formed at regular intervals with a track interval e1.

[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. Further, since pit writing and reading are performed for each track with one beam, there is a drawback that the readout speed is slower than the multi-beam multi-track readout method.

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 disk device of the present invention is based on a recording medium in which two adjacent recording guides are paired at an interval equal to or less than the writing light beam spot width, and this pair is regarded as one track pair, and a recording pit is written and read. In an optical disk device equipped with an optical head that irradiates a light beam for recording, pits are formed by irradiating a writing light beam onto each of the two recording guides that form a pair during recording, and pits form a pair during reading. The recording device is configured to perform reading by irradiating one reading light beam between the two recording guides.

[Effect]

In the present invention, two recording kites 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 reading light beam spot between the two recording guides forming a track pair, it is possible to read data on two recording guides at once with one beam. It becomes possible to increase the speed. Furthermore, by irradiating the two writing light beam spots one by one onto the two recording guides forming a guide pair, data can be recorded on the two recording guides in one rotation. .

〔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 a pair of recording tracks 'r, 1. T, □～T ll+T
+2~T nt, T n2 (n is a positive integer, i is 1≦
i≦n integer) is the track interval between each pair of recording tracks! □, each pair of adjacent recording tracks is formed with a track interval e+.

Here, (!r>ez, the track spacing e2 is narrower than the recording pit width, and the track spacing !1 is the same as in the prior art described above.

Pit 2, 3.4 are recorded on the pair of recording tracks T + 1 + T 12, and pits 2 to 4 are recorded on the recording guide formed in advance at the time of disc manufacturing. It is recorded only for continuous printing at the time of manufacture, as in It is something.

Further, reading of the pits on the paired recording tracks T+t and T12 is performed using the successive light beam spot 5. The successive light beam spot 5 has a size larger than the track interval 22, and irradiates the middle of recording track T, T, 2 to form a pair of two recording tracks 'r'+t.
, Tt□ can be irradiated simultaneously.

A method in which a guide pair is formed in the recording guide arrangement corresponding to the recording tracks T, , T, 2, and the readout light beam spot 5 is irradiated to the middle of the two recording guides forming the guide pair during readout. It is.

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), when the pit 2 is on the recording track T11, the left half of the light receiving pattern 5a reflected from the optical disc 1 of the read 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 5c for reading are shown, respectively.

Further, FIG. 2(d) shows a light reception pattern 5d when a recording track without pits is irradiated.

In this way, by irradiating the successive light beam spot 5 between the paired recording tracks T11°T1□, the expected difference in pits is detected as a difference in the light reception pattern, and the pits are read out. .

In FIG. 2(a), since the right half of the successive light beam spot 5 is affected by the diffraction caused by the track groove, 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). It is the opposite of L. Furthermore, in FIG. 2(C), since the successive 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
), the successive light beam spot 5 is affected by the diffraction caused by the two track grooves, and the light receiving pattern 5. becomes brighter overall.

As a result, by detecting the difference in pits as a difference in the light receiving pattern, one successive light beam spot can be used for two
It becomes possible to read the pits on the recording track of a book.

Therefore, the track spacing e2 is set to 1/2 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 one time, the readout speed can be twice that of the conventional method.

Next, FIG. 3 is a plan view of a main part of the optical disc showing the positional relationship on a pair of recording tracks of the writing light beam spot and the successive light beam spot for recording the pits shown in FIG. 1.

As shown in FIG. 3, a writing light beam spot 6. which is larger than the recording track interval is placed on each of the paired recording tracks T, .
7 are irradiated so as to sandwich the successive light beam spot 5. Note that arrow A indicates the direction of movement of the optical disc surface.

Methods for generating three light beams include methods that have been reported so far, such as a method using a single light source and dividing it into multiple light beams using a diffraction grating, or a light source using an array laser, etc. A method of generating multiple beams using a method, and a method of combining this method with wavelength multiplexing technology are used.

FIG. 4 and FIG. 5 are schematic diagrams of an optical disc showing the positional relationship on the recording track of the pair of the writing light beam spot and the reading light beam spot used in the second and third embodiments of the present invention, respectively. FIG.

As shown in FIGS. 4 and 5, the reading light beam spot 5 is controlled to irradiate after the two writing light beam spots 6.7. Note that in FIGS. 4 and 5, arrow A indicates the direction of movement of the optical disk surface.

As a result, two recording tracks T, , T
, 2 can be written and read simultaneously, making it possible to configure a RAW disk.

〔Effect of the invention〕

As explained above, the present invention provides a method of 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 successive light beam spot larger than the interval. This has the effect of increasing recording density and reading speed compared to conventional methods6.
Furthermore, by irradiating two writing light beam spots onto two separate recording tracks forming a pair, writing is simultaneously performed on two recording tracks, so one beam can write one
This has the effect of increasing the writing speed compared to the conventional method of writing on each track of a book.

[Brief explanation of the drawing]

FIG. 1 shows the shape of pits recorded using the present invention (d), which shows the correlation between the pits, the reading light beam spot, and the light-receiving pattern when reading the pits shown in FIG. 1, respectively. 3 is a plan view of the main part of an optical disc showing the positional relationship on the recording track of the pair of the writing light beam spot and the successive light beam spot for recording the pits shown in FIG. 1, and FIG. FIG. 5 shows the second embodiment of the present invention, respectively.
6 is a plan view of a main part of an optical disc showing the positional relationship on a recording track of a pair of a writing light beam spot and a reading light beam spot used in the third embodiment. FIG. 6 is a recording diagram of a conventional optical disc device. FIG. 2 is a plan view of a main part of an optical disc used in an example of a reading method. 1.1a... optical disc, 2,3.4... pit,
5... Light beam spot for reading, 5a to 5d... Light receiving pattern, 6, 7... Light beam spot for writing, e
s, j' 2- track spacing, T, T11. T
, □~T 11. T I2~Tnl-+ Ta2...
'Recording track.

Claims (1)

[Claims] A recording medium in which two adjacent recording guides are paired with an interval equal to or less than the width of a writing light beam spot, and this pair is regarded as one track pair, and an optical head that irradiates a light beam for writing and reading recording pits. An optical disc device comprising:
During recording, pits are formed by irradiating each of the two paired recording guides with a writing light beam;
A recording/reading method for an optical disc device, characterized in that during reading, reading is performed by irradiating one reading light beam to the middle of the two recording guides forming a pair.