JPS62293530A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To obtain a medium while the C/N is kept excellently without being subject to the effect of pre-group or information pit mutually by forming an information track of both sides of a medium in zigzag mutually so as not to be overlapped. CONSTITUTION:Pre-groups 12a/12b are formed at a prescribed interval concentrically in the radial direction of A/B sides of a disk base 10 or in zigzag and information pits 14a/14b are formed concentrically along the pre-groups 12a/12b on the face of dums 13a/13b of the A/B sides. Further, the pits 14a/14b are formed by focusing the laser luminous flux 18 of an optical disk head provided near the side A of the base 10 by an objective lens 16 onto the dums 13a, 13b and even when the luminous flux 18 is radiated onto the pit 14b, the light is reflected by the pit 14b and passes through the lens 16 again, and the reflected light is not interfered with the reflected light reflected by the pit 14a and the C/N is kept in an excellent way.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an optical information recording medium such as an optical disk, and in particular, information pits are formed on the back surface of the information recording medium to record information. The present invention relates to an improvement of an optical information recording medium for recording and reproducing information.

(Prior Art) Disc substrates for optical discs known as optical information recording media have conventionally included, in addition to flat substrates, substrates on which pre-groups (guide grooves) for recording information are formed in advance on the surface of the medium. This board has a pitch of 1.6 to 2.5μ
A groove having a width of 0.5 to 0.8 μm + a depth of about r/8 is formed, and information bits are formed along this groove.

FIGS. 4(a) and 4(b) show a conventional disk substrate in which the above-mentioned pre-groups are formed on both the front and back surfaces of the disk substrate.

As shown in the figure, a plurality of rows of pre-groups 12a (side A side) and pre-groups 12b (side B side) are formed on both the front and back surfaces of the disk substrate 10 so as to have grooves at opposing positions on both sides. There is. In such a disk substrate 10, an optical head (not shown) is usually provided on one side, and the A side and the B side are irradiated with a Rade beam 18 converged by an objective lens 16 provided on the optical head. The information is recorded and reproduced in this manner. That is, objective lens 1
6 is moved up and down with respect to the substrate 10, the laser spot 17 is irradiated onto the pre-group 12a surface or 12b surface, and the laser spot 17 is irradiated onto the pre-group 126 surface as shown in FIG. 4(a).
4(b) for the pre-group 12b surface.
).

(Problems to be Solved by the Invention) However, when recording and reproducing information to and from the information pits 14b formed on the far side surface of the objective lens 16, that is, the surface of the pregroup 12b, as shown in FIG. To,
On the way to the pre-group 12b on the B-plane, the laser beam 18 converged by the objective lens 16 passes through the pre-group 12m on the A-plane, is reflected by the pre-group 12b, and when passing through the pre-group 12a again, the reflected light There was a problem in that the light reflected by the grid group 121 interfered with each other, degrading the C/N ratio.

In particular, this deterioration of the C/N ratio is remarkable when reproducing information for which information peaks 14a have already been formed in the pre-group 12 &, and the C/N ratios are significantly different when reproducing side A side and reproducing side B side. There was a problem that they were different.

Further, this deterioration of the C/N ratio has caused deterioration in the accuracy of tracking control and focusing control of the objective lens 16.

In view of this, the present invention aims to prevent the C/N ratio from deteriorating due to the influence of pre-groups and information bits when recording information on a medium having tracks on both sides as described above or reproducing recorded information. The purpose of the present invention is to provide an optical information recording medium that is free of .

(Means for Solving the Problems) The problem with the prior art as described above is that in the optical recording medium of the present invention, which has tracks on both the front and back surfaces on which information has been previously recorded or where information will be recorded. What is claimed is: 1. An optical information recording medium characterized in that: is formed at a position where the back side and the front side of the medium do not overlap.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1(,) and (b) are cross-sectional perspective views showing one embodiment of the present invention, FIGS. 2(a) and (b) are cross-sectional perspective views showing another embodiment of the present invention, and FIG. 1 is a configuration diagram of an information recording/reproducing apparatus in this embodiment.

In addition, in these figures, FIG. 4 (a) showing the prior art is
) and (b), parts having the same functions are given the same reference numerals.

In the embodiments of the present invention, a transparent Y'' isk substrate on which information trunks are formed concentrically will be used as an optical information recording medium.

In FIGS. 1(&) and (b), reference numeral 10 denotes the disk substrate of this embodiment, and pregroups 12a and 12b are formed concentrically in the radial direction of the substrate 10 on the A side and B side of the disk substrate 10. Further, information pins (14) are placed on the bank portion 13a on the side A of the board 10 at regular intervals.
14b are pre-groups 12a and 12, respectively, on the bank portion 13b surface on the side of the substrate 100B.
It is formed concentrically along b.

Above information pin) 14m and 14b are disk board 1
An objective lens 16 of an optical disk head 15 (see FIG. 3) provided near the substrate 10 on one side of the substrate 10, for example, on the side A.
A beam of light 18 is focused and formed on the bank portions 13a and 13b on the side A and side B, respectively.

Also, the laser beam 18 is directed to the embankment 1 on the A side or the B side.
A focus servo for focusing on the 3m and 13b planes and a tracking servo for the information track formed as above? To do this, a control device configured as shown in FIG. 3 is used.

Reference numeral 10 denotes the disk substrate, and the substrate 10 is rotationally driven by a spindle motor 30 and rotated at a predetermined rotation speed by a spindle control circuit 32.
The device is configured to be able to both record and reproduce information on the device. 34 is a tracking servo circuit, which outputs a tracking control signal in accordance with the value of the tracking error signal a from the optical disk head 15 so as to obtain a correct tracking state. 36 is focus
The sensor is a circuit that outputs a focus signal d according to the value of the focus error signal C from the optical disk head 15. This control signal d is converted into 40 C by 38 adders.
It is added to the focus offset signal e from the PU,
The addition output f is input to the optical disk head 15 as a focus control signal.

Here, the focus offset signal e is the disk substrate 1.
This is a control signal for switching the recording/reproducing surface of 0 between the A and B sides of the board 10, and is controlled by the CPU K of 40. Further, the recorded data and the reproduced signal are transmitted to the outside through a signal processing circuit 42. Also, 1
is a control line with the CPU.

With the above configuration, information is recorded and reproduced on the A side and the B side of the disk substrate 10.

Therefore, the disk substrate 10 configured as described above
In this case, the information pins 14m and 14b formed on the A side and the B side of the substrate 10 are arranged on the A side and the B side, respectively.
Since they are formed at alternate positions on the B side, even when the beam 18 is irradiated onto the information pits 14b on the B side, the reflected light is reflected by the information pits 14b and passes through the objective lens 16 again. Unlike the conventional f-isk substrate, there is no interference from the reflected light reflected by the information pits 14m on the A side, and the C/N ratio is maintained at a good level.

Next, FIGS. 2(a) and 2(b) show another embodiment of the present invention.

The other embodiment shown in FIG. 2(,) is different from the above embodiment in that the embodiment is
Information pits 14m, 14b are formed on the bank portions 13m, 13b, which are generated when the pre-groups 12a, 12b are formed on the surface and the B surface, whereas in this embodiment, the information pits 11, 14b is the groove portion 15m of the groove 12m, 12b, 15b.
It is formed on a surface.

The formation state of the pre-groups 12a and 12b in this embodiment is the same as in the previous embodiment, when the pre-groups 12a and 12b are formed on the disk substrate 100.
They are formed alternately on the A-side and B-side of the substrate 10 at regular intervals in the radial direction, and on the groove surfaces 15a, 15b of the pre-groups 12a, 12b formed in this way. Information pit 14a.

Since the information pit 14b is formed, the information pit 14&.

The information pins 14b are formed alternately on both sides of the disk substrate 10, and similarly to the embodiment described above, the light reflected by the information pins 14b on the side B side is transmitted to the information pins 14 on the side A side.
There is no interference with the reflected light reflected by a (the C/N ratio is also kept good).

Further, FIG. 2(b) shows still another embodiment. In this embodiment, the disk substrate 10 is similar to the conventional example.
The pre-groups 12a and 12b are formed at opposing positions, but the information pin 14a.

14b are formed alternately in the radial direction of the disk substrate 10, so that the C/N
The ratio is also kept good.

'pP+5 whistle Q times (kl-7blAiI+A
rir+ mllnr7, 18i l, -1--)!
t) An example is shown in which information pits 14a and 14b are formed on the surface of the groove 158 of the regroove 14a, and on the surface of the bank 13b of the disk substrate 10 on the B side. , 14b on the A side is the bank part 13a, and the B side is the groove part 15.
It can also be formed on the b-plane.

Further, in the embodiment of the present invention, writing is possible as an optical information recording medium, and RAW (Direct read a) is possible.
fterwrite) type,
Not limited to this, Read on CD, LD, etc.
ly 00 (read-only optical disc) type or Wr
It is also applicable to a once OD (write once optical disc) type.

(Effects of the Invention) As is clear from the above description, the optical information recording medium of the present invention has information tracks alternately formed on both sides of the information recording medium, so that information tracks are formed alternately on both sides of the recording medium.
Even when recording and reproducing In information, there is no mutual influence of pre-groups or information pits, so the C/N ratio can be kept good, and tracking control and focusing control can also be performed well.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are cross-sectional perspective views of one embodiment of the present invention, FIGS. 2(a) and 2) are cross-sectional perspective views of another embodiment of the present invention, and FIG. FIG. 4 is a configuration diagram of the information recording/reproducing apparatus in the embodiment, and is a cross-sectional perspective view of the prior art. DESCRIPTION OF SYMBOLS 10... Disk board, 12m, 12b... Pre-group, 14a, 14b... Information pit, 1
6... Objective lens, 18... Rede luminous flux. Agent Patent Attorney Seki Yamashita Figure 1 (b) Figure 2 (a) (b) Figure 4 (G) (b)

Claims (3)

[Claims] (1) An optical recording medium having tracks on both the front and back surfaces on which information has been previously recorded or where information will be recorded, characterized in that the tracks are formed at positions where the back and front surfaces of the medium do not overlap. information recording medium. (2) The optical information recording medium according to claim 1, wherein the track is provided in either a groove portion or a bank portion of a guide groove formed in advance on the medium. (3) Guide grooves are formed in advance at opposing positions on both the front and back sides, and the track is provided in the groove of the guide groove on one of the front and back sides, and the track is provided on the bank of the guide groove on the other side. The optical information recording medium according to claim 1, wherein the optical information recording medium is provided with: