JP3252027B2 - Optical information recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus.

[0002]

2. Description of the Related Art Conventionally, in a recording method of an optical information recording medium (for example, an optical disk in this case), a tracking groove called a guide groove is formed, and a groove recording method of recording information in the guide groove is known. There is a land recording method for recording information between the guide grooves.
FIG. 8 shows a format in one sector to be recorded. The format includes a position information section (ID section) 1 in which an address signal and a synchronization signal are recorded, and a data section 2. FIG. 9 shows the surface shape of the ID portion 1 of the optical disc 3, in which land portions (L) 4 and groove portions (G) 5 are alternately arranged along the track direction. In this case, in the land recording type optical disk, position information is recorded by forming pre-pits 6 on the land portion 4. In an optical disk of the groove recording type, position information is recorded by forming a guide groove 7 in a groove portion 5 and a discontinuous portion (mirror portion) 8 therebetween.

[0003] Using an optical disk on which groove recording is performed,
Laser beam (not shown, about 1 μm diameter) on the disk surface
As shown in FIG. 10 (b), the level of the amount of reflected light increases at the position of the mirror surface portion 8 between the guide grooves 7, so that a position information signal (ID signal) of the groove portion 5 can be obtained. . On the other hand, when a laser beam is irradiated on the disk surface using an optical disk on which land recording has been performed, light is scattered at the position of the prepit 6 formed on the land portion 4, and as shown in FIG. The position of the reflected light amount is lowered at the position 6, whereby the land 4
Can be obtained.

In general, the guide groove 7 in the groove 5
Of the track error signal T as shown in FIG.
In order to obtain r sufficiently, it is desirable to form λ / 8n (where n is the refractive index of the transparent substrate and λ is the wavelength of the laser beam), and the depth of the prepit 6 is the contrast (the λ / 8n depth of the reflected light amount). Λ / 4n to increase the difference between
It is desirable to form it. In addition, since the depth of the mirror surface portion 8 between the guide grooves 7 corresponds to 0 in FIG. 11, the amount of reflected light is large, so that the track error signal Tr is not generated.

[0005]

In recent years, not only optical information recording media dedicated to land recording or groove recording as described above, but also PC (Phase) having low thermal conductivity in recent years.
Charge) Use a media or the like to easily reduce the recording capacity to 2
A land and groove recording method that can be doubled has been proposed. As this land & groove recording method, for example,
“High Track Density Magn” was added to Optical Data Strage'90.
eto-optical recording Using a CrosstalkCanceler ”
Are disclosed. Lands like this
In the groove recording method, the width of a land (or groove), which has conventionally served as a guide groove, is increased, and data is recorded not only in the land but also in the guide groove of the groove by using three beams or the like. By doing so, high-density recording is performed.

However, when such land & groove recording is performed, in the conventional optical information recording medium, for example, in the ID section 1 of the optical disk 3 as shown in FIG. On the other hand, the groove portion 5 is a shape formed by the guide groove 7 and the mirror surface portion 8 (interruption portion), and in order to produce such a shape, complicated and various processes must be performed. However, there is a problem that the production is difficult, and the output of the position information signal (ID signal) from the land portion 4 and the output of the ID signal from the groove portion 5 are different, so that the signal processing is difficult.
Further, in the conventional groove recording, since the guide grooves 7 in the groove portion 5 are formed intermittently, there is a problem that the track error signal Tr becomes unstable and tracking is easily shifted.

[0007]

[0008]

According to the present invention, a pre-pit recorded as position information is formed in a position information portion of a land portion, and the pre-pit is wobbled at a non-constant frequency in the position information portion of the groove portion. An optical information recording medium provided with a guide groove for recording information is provided, and information is recorded by irradiating the optical information recording medium with a laser beam, and a reflected beam from the optical information recording medium is divided into two parts. In an optical information recording / reproducing apparatus for reproducing information by detecting light on a light receiving surface, a reflected beam from a position information section of the groove section having a guide groove wobbled at a non-constant frequency of the optical information recording medium is used as the light beam. A groove section for generating a position information signal of the groove section by detecting the divided light receiving surface and obtaining a difference signal from the two divided light receiving faces. Provided location information signal generating means, the sum signal from the two divided light receiving surface is detected on the same 2-split light receiving surface and the light receiving surface thereof a reflected beam from the position information portion of the land portion of the optical information recording medium And a land portion position information signal generating means for generating a position information signal of the land portion by obtaining the following.

[0009]

[0010]

[0011]

[0012]

[0013]

In the present invention, the position information signal of the groove portion is obtained by using a difference signal from the two divided light receiving surfaces, that is, a track error signal, and the position information signal of the land portion is a sum signal from the same two divided light receiving surfaces. Thus, independent signals can be detected without error without changing the output level.

[0014]

[0015]

[0016]

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an optical information recording medium on which the present invention is based will be described with reference to FIGS. The description of the same parts as those in the related art (see FIG. 9) is omitted, and the same parts are denoted by the same reference numerals.

FIG. 1 shows a position information section (I) of an optical information recording medium (hereinafter referred to as a write-once optical disc) capable of recording and reproducing information in both areas of the land section 4 and the groove section 5.
3 shows the surface shape of D part 1). In the ID section 1 of the land section 4 of the optical disc, prepits 6 are recorded which are recorded as positional information similar to the conventional one. In this embodiment, in such an optical disc,
It is characterized in that a guide groove 7 wobbled at a non-constant frequency is formed in the ID section 1 of the groove section 5 and position information is recorded in the wobbled guide groove 7. FIG. 2 shows a perspective view of the ID section 1 of the optical disc. In this case, the track pitch is 1-2 μm
And the depth (λ / 8n) of the guide groove 7 is 60 to 80 nm.
And The guide groove 7 in the groove 5 has a wobble amount set to about 1/5 of the track pitch and a frequency higher than a frequency at which a lens (not shown) is driven. . When the position information is obtained by reproduction, the center of the wobbled groove portion 5 is scanned, and the frequency of the continuous track error signal Tr obtained thereby is obtained.
The position information recorded in the unit 1 can be obtained as an ID signal. In this case, the reflected light amount obtained by irradiating the laser beam to the land portion 4 having the prepit 6 and the groove portion 5 wobbled at a non-constant frequency has a waveform similar to that of FIG.

Since the guide groove 7 in the ID portion 1 is formed by wobbling at a non-constant frequency in this manner, there is no portion corresponding to a discontinuous portion as in the prior art, so that the track error signal Tr becomes unstable. It is possible to eliminate the phenomenon that the track is shifted, and to always perform stable tracking. In addition, the configuration of the control circuit can be simplified. Further, the optical disk having the guide groove 7 formed by wobbling without any discontinuity can be manufactured by simplifying the manufacturing process as compared with the conventional optical disk as shown in FIG. Manufacturing can be further facilitated.

In this embodiment, the ID of the groove 5
The guide groove 7 formed in the portion 1 may be wobbled with the same amplitude and phase in the right and left directions with respect to the track direction T. The above-described guide groove 7 in FIG. 1 shows a state in which the left and right wobble amounts (amplitude) and phases are formed to be the same with respect to the track direction T (1 in FIG. 1).
01 and 102 and 103 and 104). In the groove section 5 having the same wobble amount and phase on the left and right as described above, by performing tracking at the center, a stable wobble signal can be obtained, and accurate ID signal detection can be performed. . In addition, by manufacturing the optical disc 3 with the same wobble amount and phase on the left and right with respect to the track direction T, the optical disc 3 whose wobble amount and phase are not formed in the same direction due to some reason during the manufacturing process. In the inspection process, the recording medium can be easily and surely found, so that a highly reliable recording medium can be provided.

Further, in this embodiment, the ID portion 1 of the groove portion 5 wobbled at a non-constant frequency may be arranged adjacent to the ID portion 1 of the land portion 4 formed in the track direction T. FIG. 3B shows the optical disk 3 shown in FIG.
(G, L, G) of the track in the outer peripheral area of FIG. As shown in FIG. 3B, by making the ID portion 1 corresponding to the head position of one sector coincide with the groove portion 5 and the land portion 4, the detection of the ID portion 1 becomes easy, whereby the ID portion which is always stable can be obtained. The position of the unit 1 can be detected.

Next, another example of the optical information recording medium will be described with reference to FIG. The description of the same portions as those of the above-described optical information recording medium is omitted, and the same reference numerals are used for the same portions.

In this embodiment, the above-mentioned basic structure of the present invention is explained.
Optical disc 3 as described in the embodiment of the optical information recording medium
In addition, the following functions are added. That is, a pre-pit 6 to be recorded as position information is formed in the ID portion 1 of the land portion 4 and the pre-pit 6 of the groove portion 5 is formed.
In the optical disc 3 on which the guide groove 7 is recorded as position information by being wobbled in the D section 1 at a non-constant frequency, the guide groove 7 wobbled at the non-constant frequency is also formed in the data section 2 of the groove section 5. The formation of the wobbled guide groove 7 is characterized by recording position information in a sector located one after the sector in which the wobbled guide groove 7 is formed.

More specifically, as shown in FIG. 4, in the first sector 9, not only the guide groove 7 of the ID section 1 but also the guide groove 7 of the data section 2 are formed by wobbling at a non-constant frequency. Have been. Data part 2 in the first sector 9
The wobbled guide groove 7 records the position information in the second sector 10 following the subsequent stage. Thus, by forming the position information by wobbling in the data portion 2 of the sector (first sector 9) immediately before the sector to be recorded and reproduced (second sector 10), the data portion 2
, The data capacity can be increased, and a stable ID signal can be generated by increasing the wobble frequency. That is, in the data format of FIG.
The D section 1 uses 52B, which is 7% of 725 bytes (B) of one sector. The ID section 1 is formed by wobbling the data section 2 of the immediately preceding sector (first sector 9). One round 27
The capacity can be increased by about 7 to 8% such as 40 sectors per sector. Therefore, by forming the position information of the ID section 1 by wobbling the guide groove 7 of the data section 2 in the immediately preceding sector, the recording capacity of the groove section 5 can be increased. Note that the present invention is applicable to all write-once optical disks, phase-change optical disks, and magneto-optical disks as optical information recording media.

Next, an embodiment of the present invention will be described with reference to FIGS. The description of the same portions as those of the above-described optical information recording medium is omitted, and the same reference numerals are used for the same portions.

In this embodiment, prepits 6 to be recorded as position information are formed in the ID portion 1 of the land portion 4 and wobbled at a non-constant frequency in the ID portion 1 of the groove portion 5 to be recorded as position information. that the guide groove 7 is an optical information recording medium as described in the previous example mentioned formed (hereinafter referred to as the optical disk 3) with, the optical disk 3
The present invention relates to an optical information recording / reproducing apparatus which records information by irradiating a laser beam onto the optical disc 3 and reproduces information by detecting a reflected beam from the optical disc 3 on a two-divided light receiving surface.

Therefore, before describing the configuration of the main part of the present embodiment, an outline of the overall configuration of an optical pickup device used as an optical information recording / reproducing device will be described with reference to FIG. The laser beam emitted from the semiconductor laser 11 is collimated by a collimator lens 12, is condensed by an objective lens 14 via a beam splitter 13, and is irradiated onto the surface of the optical disc 3, thereby recording information. Etc. are performed. The reflected beam from the optical disk 3 is deflected by the beam splitter 13 via the objective lens 14 and guided to the light receiving element 15 having two divided light receiving surfaces A and B, thereby reproducing information.

Next, the configuration of the main part of this embodiment will be described. Here, the ID of the groove section 5 as described above is used.
In an optical pickup device for recording and reproducing information using the optical disk 3 having the guide groove 7 wobbled at a non-constant frequency in the section 1, as shown in FIG. The reflected beam from the ID portion 1 of the groove portion 5 having the guide groove 7 is detected by the two-divided light receiving surfaces A and B, and the difference signal from the two divided light receiving surfaces A and B is obtained, whereby the ID signal of the groove portion 5 is obtained. A groove portion position information signal generating means 16 for generating P;
The reflected beam from the ID portion 1 of the land portion 4 of the optical disk 3 is detected by the two-divided light receiving surfaces A and B, and the two divided light-receiving surfaces A
A land position information signal generating means 17 for generating an ID signal Q of the land 4 by obtaining a sum signal from B is provided.

The groove position information signal generating means 1 will now be described.
6 and the specific operation of the land portion position information signal generating means 17 will be described. The reflected beam from the optical disc 3 having the guide groove 7 wobbled at a non-constant frequency is detected on the light receiving surfaces A and B of the light receiving element 15. At this time, the position information from the pre-pit 6 recorded in the ID portion 3 of the land portion 4 is obtained by transmitting an output signal from the light receiving surfaces A and B to the land portion position information signal generating means 17 so that the sum signal (A +
B) is obtained from the ID signal Q. The method of obtaining the sum signal in this manner is the same as the conventional detection method in the land portion 4. On the other hand, the ID of the groove 5
The position information from the guide groove 7 wobbled and recorded at the non-constant frequency in the section 1 is output from the light receiving surfaces A and B to the groove section position information signal generating means 16 so that the difference signal (A-B) is obtained. )).
The method of obtaining from such a difference signal is the same as the known method of detecting a track error signal.

That is, in the detection of the track error signal (that is, the ID signal P in this case) in the groove portion 5, when the optical axis of the objective lens 14 and the center of the guide groove 7 coincide, FIG. As shown in FIG. 3A, a symmetrical light quantity distribution 18 is obtained.
−B) is 0, but if they do not match, FIG.
(B) As shown in FIG.
The value of the track error signal does not become 0, but the direction of the track shift is detected. Accordingly, the objective lens 14 is driven by an actuator (not shown) to reduce the track shift to 0.0.
Adjust to 1 μm or less. By detecting the track error signal in this manner, tracking is performed, and at the same time, the frequency of the continuously changing track error signal (because the ID signal due to wobble is a high frequency that the tracking servo of the objective lens 14 cannot follow, I
By detecting the D signal P, the wobble frequency can be detected faithfully), the ID signal P serving as the position information of the groove portion 5 can be detected. Accordingly, the ID signal P of the groove portion 5 is obtained from the difference signal as the track error signal from the two-divided light receiving surfaces A and B, and the ID signal P of the land portion 4 is obtained.
By obtaining the D signal Q based on the sum signal from the two divided light receiving surfaces A and B, independent signals can be detected without changing the output level, thereby eliminating erroneous detection and detecting an accurate ID signal. It can be carried out.

[Brief description of the drawings]

[1] shows one embodiment of the underlying optical information recording medium of the present invention, is a plan view showing the shape of the surface of the position information of the optical information recording medium.

FIG. 2 is a perspective view of a position information unit.

FIG. 3A is a plan view of an optical information recording medium, and FIG. 3B is a schematic diagram showing a partial shape of a track thereof.

FIG. 4 is a schematic view showing another example of the optical information recording medium and showing a partial shape of a track of the optical information recording medium.

FIG. 5 is a configuration diagram showing an entire optical system of an optical information recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 6 is a circuit diagram showing a means for generating a position information signal of a groove portion and a land portion.

FIG. 7A is a schematic diagram showing a light amount distribution when a track is not displaced, and FIG. 7B is a schematic diagram showing a light amount distribution when a track is displaced.

FIG. 8 is a schematic diagram showing a format configuration of a sector.

FIG. 9 is a perspective view showing a shape of a position information section of a conventional optical information recording medium.

10A is a waveform diagram showing the amount of reflected light at a land portion and a groove portion according to the present invention and the amount of reflected light at a conventional landmark, and FIG. 10B is a waveform diagram showing a conventional groove mark (mirror portion is convex); FIG. 9 is a waveform diagram showing the state of the amount of reflected light at (part).

FIG. 11 is a characteristic diagram showing a state of a reflected light amount and a track error signal with respect to a guide groove depth.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Position information part 3 Optical information recording medium 4 Land part 5 Groove part 6 Pre-pit 7 Guide groove 16 Groove part position information signal generation means 17 Land part position information signal generation means A, B 2 divided light receiving surfaces

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ikuo Aoki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-6-139582 (JP, A) JP-A-Hei 1-241043 (JP, A) JP-A-3-181023 (JP, A) JP-A-64-35727 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 7/00 -7/013 G11B 7/24

Claims (1)

(57) [Claims] A guide groove to be recorded as position information is formed by forming a pre-pit recorded as position information in a position information portion of a land portion and wobbling at a non-constant frequency in a position information portion of the groove portion. The optical information recording medium is provided with a laser beam, and the information is recorded by irradiating the optical information recording medium with a laser beam. In the optical information recording / reproducing apparatus for performing reproduction, a reflected beam from a position information portion of the groove portion having a guide groove wobbled at a non-constant frequency of the optical information recording medium is detected by the two-divided light receiving surface, and the two divided light-receiving surfaces are detected. A groove portion position information signal generating means for generating a position information signal of the groove portion by obtaining a difference signal from a light receiving surface; The reflected beam from the position information portion of the land portion of the information recording medium is converted into the same light beam as the two divided light receiving surfaces.
An optical information recording / reproducing apparatus comprising a land portion position information signal generating means for generating a position information signal of the land portion by detecting a divided light receiving surface and obtaining a sum signal from the two divided light receiving surfaces.