JPS6018832A - Optical informaton disk and its recording and reproducing device - Google Patents

Abstract

PURPOSE:To ensure the recording/reproduction of information signals by means an optical picup by giving displacement to the pickup while applying the tracking control so that the pickup is set as opposed to the top and bottom areas of an information disk. CONSTITUTION:The guide grooves are formed spirally or concentrically with certain spaces. The light delivered from a laser light source 10 is divided into two parts by a half mirror 12. One of these two divided beams is irradiated an information signal recording part on the surface of a disk 6 via a recording/reproduction lens 8 in the form of the laser light for recording/reproduction. Thus the recording/reproduction is carried out. The lens 8 has a number of apertures so that a focused spot diameter is equal to the track width. While the other beam is irradiated to the guide groove on the surface of the disk 6 via a lens control lens 9 for tracking control, and a tacking control signal is obtained from the reflected signal supplied from the disk surface. The lens 9 has a smaller number of apertures than the lens 8 and is fixed at a position on a line connecting the lens 8 and the revolving center of the disk 6 and close as much as possible to the lens 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information disc and a recording/reproducing device thereof;
To provide an information disk with high recording density and low crosstalk by recording information signals on both the mountain portions and the row portions of an information disk having a trapezoidal cross section, and to record information signals on the mountain portions and the row portions. It is an object of the present invention to provide a recording and reproducing device that can reliably record and reproduce data.

For example, a magnetic recording film disk that has been previously magnetized in the same direction is irradiated with laser light modulated by an information signal in a magnetic field, the magnetization of that portion is reversed, and an information signal sequence is recorded. A photothermal magnetic disk for reproducing information signal sequences from this disk has been developed.

Therefore, it is necessary to control the tracking of the optical system that records the information signal and reproduces it so that it correctly traces the information signal track.There is a type of disk in which a tracking guide groove or protrusion is provided in advance on the disk. .

The former type of disk, for example, as shown in FIG. 1(A), forms information signals 2+ + 22, . Row portion 31.32. '... is used as a tracking reference groove, and as shown in FIG. A tracking control signal is obtained by the reflected diffraction light. On the other hand, contrary to the structures shown in FIGS. 1A and 1B, there is also a structure shown in FIG. 2A. Second
As shown in FIG.
2. ... are used as tracking reference protrusions, and as shown in the figure ([3)], when the laser beam is reproducing the signal 52 of the row section 32, the peaks 11 and 12 on the left and right are A tracking control signal is obtained by the reflected diffraction light.

However, in these conventional systems, the information signal is
The one shown in (B) is formed only on the mountain portions 11, 12, etc., and the one shown in Fig. 2 (A>, (B) is formed only on the row portions 3+, 32, ... i.e.,
Although these devices have two parts, a mountain part and a row part, the information signal is only formed in one of these parts, so they have a drawback of low recording density.

Therefore, in order to record information signals with high density, if you try to record signals on both the mountain portions and the row portions, as shown in FIG. 3, the width of the information signals 21 and 51 and the width of the signal track will be approximately Since they are the same, it is practically unavoidable that the information signals on each signal track come into contact with each other and that a cross occurs between adjacent tracks on both sides. This means that the spot diameter of the laser beam, which is the signal detection means, and the width of the signal track must be completely the same, and it is almost impossible to ensure that the diameter of the laser beam slot I is within the signal track during recording and reproduction. This is because it is almost impossible.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described with reference to FIG. 4 and subsequent figures.

FIG. 4 shows a schematic diagram of an embodiment of an optical information disc recording/reproducing apparatus according to the present invention. In the same figure, 6 is an information disk (disc), as shown in FIG. 3, it has a guide groove similar to that shown in FIGS. are formed spirally or concentrically with regular intervals.

A recording medium made of a suitable material is coated with a uniform thickness on the surface of the disk 6, and information signals are transmitted by using, for example, changes in geometric shape, changes in optical properties, magneto-optic effects, etc. recorded.

Reference numeral 10 denotes a laser light source, and the light emitted from this source is divided into two by a 6-7 mirror 12. One of them is irradiated as a recording/reproducing see light through a recording/reproducing lens 8 to an information signal recording portion on the surface of the disk 6, and recording/reproducing is performed. The lens 8 is an I-nons having a frontage such that the focused diameter of the aperture is equal to 1-rack width. Reference numeral 11 denotes a light detector which detects signals and focus control signals.

Next, the other half of the light divided into two by the half mirror 12 is
The light is irradiated onto the guide groove on the surface of the disk 6 through the tracking control lens 9, and a tracking control signal is obtained from the signal reflected from the surface. The lens 9 has a smaller numerical aperture than the lens 8, and is mounted as close to the lens 8 as possible on a line connecting the lens 8 and the center of rotation of the disk 6. When this relationship exists, the influence of eccentricity on the l-racking control signal is equal for lenses 8 and 9.

Further, the influence on the surface runout of the disk 6 is also equalized.

Slot 1 of the recording and reproducing beam obtained through the lens 8
~The diameter is smaller than that of the tracking control beam obtained through the lens 9. The relative positional relationship between lens 9 and lens 8 is that the spot focused by each lens needs to be located exactly at the center of an arbitrary range of 1 to 400 degrees, so it is difficult to maintain the relative positional relationship between lens 9 and lens 8 when tracking control is applied. The lens 8 is finely adjusted by appropriate means so that the output of the optical detector 11 is maximized.

The light focused by the tracking control lens 9 is set to be lower than a threshold value that causes a change in the recording medium of the disk 6.

FIGS. 5(A) and 5(B) are diagrams showing differences in the intensity distribution of each optical spot when recording or reproducing signals in the conventional recording/reproducing apparatus and the recording/reproducing apparatus of the present invention. Figure 5 (A)
1 is a diagram showing the state of the spots 1 to 1 by the tracking control lens 9 in the conventional device and the device of the present invention, and FIG. It is a diagram.

In FIG. 5 (A>), the spot spreads from both ends of the guide groove to adjacent areas, so that a tracking control signal can be obtained, but in the conventional device, this is only a cause of information signal cross.

On the other hand, in FIG. 13 (13), the spot produced by the recording lens 8 does not spread to adjacent tracks, so that the information signal does not generate one stalk.

Information signal 2+, 22,...5+ + 52 +・
When forming or reproducing these, the laser beam from the optical system is applied to the peaks 111, 121 and the valleys 31, 32, respectively.
, . . . , and as a result, FIG. 1(B).

As explained with reference to FIG. 2(B), the tracking control signal is extracted by the reflected and diffracted light from the peaks and valleys. The tracking control signal is fed back to the recording/reproducing lens 8 as a drive signal in the direction of eliminating the dragging error according to its magnitude, and the peak portion 1+,
12. . . , are displaced so as to correctly trace the valley portions 311321 .

As described above, the optical information disk of the present invention records information signals on both the peaks and valleys of the trapezoidal cross section, so it is possible to record information signals only on the peaks or valleys. The recording density can be doubled compared to the conventional information disk, and crosstalk from adjacent signal tracks on both sides is reduced, so a high S/N ratio can be obtained. The information disc recording/reproducing apparatus includes means for displacing an optical pickup while applying racking control so as to face the peaks and valleys of a rotating information disc; Since the device is configured with means for recording information signals on the respective peaks and reproducing the information signals, it has the advantage of being able to reliably record and reproduce the information signals on the peaks and valleys, respectively.

[Brief explanation of drawings]

Figures 1 (A) and (B) and Figures 2 (A) and (B) are perspective views of the main parts on each side of a conventional information disk, and the state in which the laser beam is irradiated onto the peaks and valleys. Diagram for explanation, 3rd
The figure is a perspective view of a main part of an embodiment of the information disk of the present invention, FIG. 4 is a schematic diagram of an embodiment of the device of the present invention, and FIGS.
) is a conventional device and 10- and optical abutments using the device of the present invention! . is a diagram showing the state of the intensity distribution. 1+, 12...111 part, 2+, 22.5+,
52... Information signal, 3+, 32... Row portion, 4.
... Laser light, 6... Information disk, 8... Recording/reproduction lens, 9... Tracking control lens, 10...
・Laser light source, 11... Optical detector, 12.13...
・Half mirror-011-

Claims (1)

[Claims] (1) A guide groove having a trapezoidal cross section consisting of a bottom surface and sloped portions on both sides is formed spirally or concentrically as repeating mountain portions and row portions at regular intervals. 1. An optical information disc characterized in that information signals are recorded on both the mountain portion and the row portion. (2) An optical information disk in which a guide groove with a trapezoidal cross section consisting of a bottom surface and sloped portions on both sides is formed spirally or concentrically as repeating mountain portions and row portions at regular intervals. In an optical information disk recording device that records information signals with an optical pickup, the optical pickup is displaced while applying tracking control so as to face the mountain portion and the row portion of the rotating information disk. 1. An optical information disc recording device comprising: a means for recording an information signal on the mountain portion and the row portion using the optical pickup. ■ An optical information disk in which a guide groove with a trapezoidal cross section consisting of a bottom surface and sloped portions on both sides is formed spirally or concentrically as repeating mountain portions and row portions at regular intervals. In an optical information disc recording and reproducing apparatus that records an information signal with an optical pickup and reproduces the information signal from the information disc with the optical pickup, the information disc that rotates the optical pickup is means for displacing the mountain part and the row part while applying tracking control so as to face the mountain part and the row part, and recording an information signal on the mountain part and the row part, respectively, with the optical pickup, and reproducing the information signal. An optical information disk recording and reproducing device comprising: means. (4) An optical information disk in which a guide groove with a trapezoidal cross section consisting of a bottom surface and sloped portions on both sides is formed spirally or concentrically as repeating mountain portions and row portions at regular intervals. In an optical information disk recording and reproducing apparatus that records an information signal with an optical pickup and reproduces the information signal from the information disk with the optical pickup, the 111 portion is recorded with a recording and reproducing lens having a predetermined numerical aperture. and means for recording information signals in the row portions and reproducing the same;
irradiating the 111 portion and the row portion with a 1-racking control light using a tracking control lens having a smaller numerical aperture than the lens for recording book A1, detecting the reflected light of A to obtain a tracking control signal; An optical information disk recording and reproducing apparatus comprising means for applying tracking control to the recording and reproducing lens using the tracking control signal.