JPS5885936A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform accurate tracking and to obtain a stable reproduced output signal, by setting the width of the groove and the space between the grooves larger than the width of a laser light beam for an optical recording disk having guide grooves. CONSTITUTION:The light of a laser light source 13 is detected 14 by a signal 15, and a disk 11 having guide grooves via a lens 16, polarizing beam splitter 17, lens 18, 1/4 wavelength plate 19, rotary mirror 20 and lens 21. Thus the information is recorded. In a reproduction mode, the disk 11 is irradiated by the laser light 13 passed through the same route as that used in the reproducing mode and with an output reduced less than that used in the recording mode. The reflected light given from the disk 11 is detected by a 2-split optical detector 22 via the lens 21, the mirror 20, the plate 19, the lens 18 and the splitter 17. The mirror 20 is driven 25 with the difference between the outputs 1a and 1b via a differential device 23 so as to set the difference at 0. The outputs 1a and 1b are added together 26 to obtain the output signal 27. The width of the guide groove and the space between the guide grooves is set larger than the beam width. As a result, the accurate tracking is possible and the stable output signal is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an optical information recording and reproducing apparatus that records and reproduces information using Raded light.

Technical background of the invention and its problems Recently, optical disk devices have been attracting attention as highly confidential and large-capacity information recording and reproducing devices. This woodcutter's device focuses, for example, Leede light to a diameter of about 1#11 and irradiates the recording medium with a diameter of 1.5 to 2 iIm.

It is used to reproduce the original. Therefore in this case 0.1
A very high tracking level of approximately 0.2μ is required. Therefore, a method has been proposed to simplify tracking by forming guide grooves on the substrate of the recording medium in advance, without relying solely on mechanical tracking control.
For example, ItEE spgc'raw AUGU8T 1
979, P26-P33).

Figure 1 shows an example of a multiplication recording medium equipped with such a guide groove. It has a structure in which a recording layer 3 and a trowel layer 4 are formed on a substrate 1 on which a guide #2 is formed in advance using Stanno 9-technique or the like. According to the above document, the width of the guide groove 2 is approximately 0.
．． 6μ steel, the optical phase difference inside and outside the groove 20 is approximately mλ/(8
・n) (λ is the Raded wavelength used, m is an odd number, n is the refractive index of the Raded light incident side material (in Figure 3, the refractive index of the substrate 31))
, the pitch is approximately 1.67 μm.

FIG. 2 is a schematic diagram of a multiplication table disk device using a disk-shaped recording medium having such a guide groove. In the figure, reference numeral 11 denotes a recording medium (optical disk) having the structure shown in FIG. 1, and a motor 12? It rotates due to C. When the bell is struck, the Raded light from the Raded oscillator 13 is transmitted to the optical f#I4 device 1.
4. Information to be recorded such as m-signal, data signal etc. No. 46 1
5, a lens 16, a polarizing beam sinter 11, a lens 18, a 1/4 wavelength plate 19, a rotating mirror 20
The light is irradiated onto the recording medium 11 via the condenser lens 21t''. As a result, information is recorded in the recording layer of the recording medium 11 as a pit string.

Here, the reproduced information signal and the tracking and king signals can be obtained from the two-split photodetector 22 that is arranged substantially in the tracking direction (tangential direction of the tracking and tracking directions). That is, when the beam center of the good radar light irradiated onto the optical disk 11 coincides with the center of the guide groove, the outputs 1@+Ib of each of the two-part detectors 22 are equal, but if this positional relationship deviates If so, one part @is is detected corresponding to the direction of the deviation, and this is applied as a tracking and king signal 24 to the drive unit 25 of the rotating mirror 20 to perform tracking so that Id*f becomes zero. Please put the information on the guide groove,)
Can be recorded in O shape.

By adding the sum Iadd (=Ia+Ib) in the adder 26, the reproduced information signal 21 is obtained.In this case, the shape of the guide groove formed on the substrate of the recording medium 11 is such that a large tracking signal is stable. It is desired to have a shape that can be obtained and has a small effect on the reproduced information signal.

Substrates with guide grooves are generally manufactured in a process similar to that used for manufacturing video discs. That is, first, a photoresist is spread on a glass substrate using a spinner or the like, and a laser beam is irradiated onto the photoresist using a master disk manufacturing device having a configuration similar to that of the optical disk device shown in FIG. By exposing the turn and etching it, a master disc with guide grooves of a predetermined shape is created.Next, from this master disc, silver plating, nickel plating, etc. are used to sequentially manufacture master discs, made discs, stunless discs, etc. Then, a large number of copies of the substrate with guide grooves are made using Stan/IF board casting or the innoexy method.

However, when this method is implemented, strict precision is required for rotational irregularities of the motor and radial feed shimmels during the production of master discs, since the guide groove has a small deviation of about 1.6771 inertia. In other words, rotational unevenness or feed unevenness causes pitch unevenness in the guide groove, and adjacent tracks and adjacent trucks,
Not only will the pits on the top of the rack be detected as crosstalk and noise, but in the worst case, there is a risk that the M*) rack will come into contact with the rack. In addition, the narrow groove width of 0.6 .mu.m restricts the flow of the f2 stick, which is the substrate material, into the groove of the stamp/glue, which causes poor transferability.

As described above, in the past, there was a problem that it was difficult to produce a recording medium using a substrate with guide grooves at a low cost.

OBJECTS OF THE INVENTION An object of the present invention is to reduce the influence of guide #IO pitch unevenness, to be able to manufacture recording media at low cost and with high yield, to have little influence on reproduced image signals, and to obtain stable tracking signals. The purpose of the invention is to provide an optical information recording and reproducing device that records the zero width of the guide groove and the width between the guide grooves.・It is characterized by making the diameter larger than the diameter at the position where 2) and transmitting information to at least one of the edge of the guide groove of the recording layer and the flat parts within the guide groove and between the guide grooves. .

Embodiment of the Invention FIG. 3 shows the relationship between a recording medium having a guide groove according to the present invention and the beam diameter of Radhe light on the recording layer.

The recording medium includes a recording layer 33 made of, for example, tellurium or a compound thereof, and a protective layer 34 on a substrate 31 made of transparent glass or the like, on which guide grooves 32 are formed by the method described above.
were formed sequentially. The Radhe light 35 enters this single medium from the substrate 31@, and is focused onto the recording layer 33 by the condenser lens 5g6c. At this time, the Rede light O enhancement distribution has a Gaussian distribution as shown in -[KvB31, so
The beam diameter is the diameter W at the point where the intensity is 17.
is given by Here, the width of the guide groove 32 is set to A1 pitch t-
When expressed as P, W<A, W<(PA) are selected.

(PA) corresponds to the width between the guide grooves 32.

FIG. 4 shows v-1,0 in the recording medium shown in FIG.
4111@A = 2.0 sm * P = 4.
Otswi, and the two-split photodetector shown in FIG. 2 is placed almost at the imaging position of the recording medium, and the positional relationship between the beam center position of the Radhe beam 35 in the tracking direction and the guide groove 32 at nine o'clock is determined. This figure shows the result of calculating the changes in the King signal (Jsiir) output using numerical integration.

In this way, when the photodetector is located approximately at the imaging position of the recording medium, the beam center position of the radar light 35 is located within the grooves, grooves 41, 42 and I guide Hsx of the guide groove 32, and within the guide #I32.
When the flat s43°440 between them is located approximately on the center,
The tracking signal Id*f becomes zero. Therefore, according to the tiger and king method explained in Fig. 2, the led light 35 is 41
Track to the position of ゜42 or 43.44,
Information can be recorded and played back.

In this case, the width and pitch P of the guide groove 32 are approximately twice as large as those of the conventional guide, but in contrast to the conventional method where information is recorded as one pit row per guide #11, this In this embodiment, two bit strings are recorded per guide groove, so that the recording density is hardly impaired.

- 10,000, Radical beam direct @ v -1,0 μ course, Radius of guide groove 31 = 3.0 all, Pitch P = g
6. 41, 42 and 4 in Fig. 4 when the photodetector is placed almost at the imaging position of the recording medium
3.44C) Information can be recorded in both positions without overlapping pits of adjacent tracks. in this case,
Although the values of A and P are even larger, since information is recorded in 221 columns of 4 columns per guide groove, there is no problem in terms of recording density inside.

FIG. 5 shows v=1. Os 禦* A=2. Opus a
Px4. Otm, the photodetector is placed in the 7 Raunhofer region of the reflected light from the recording medium, and the changes in the tracking signal output with respect to the positional relationship between the beam center position of the Rede light and the guide groove 32 at 9 o'clock are shown. It is something that

In this way, when there are many photodetectors in the Fraunhofer region, when the beam center position of the Radhe light is located approximately at the center of the flat portion 51° 52 within the guide $12 and between the guides #I32, the tracking signal Id *Since f becomes zero, record by tracking the radar light to these 61.11,
Can be played.

Effects of the Invention According to the present invention, the number of guide grooves and pips can be more than doubled compared to the conventional method.This makes it easier to control rotational unevenness during master production and the O feed shims in the radial direction. Katsuge.

Chimura's influence is reduced. Furthermore, since the width of the guide groove is wide, the transferability from a stunner or a single disc is also good. Therefore, recording media can be manufactured at low cost and with high yield.

Since the width of the housing, the guide groove, and the width between the guide grooves can be made sufficiently large relative to the beam diameter of the laser beam on the recording layer, stable tracking is achieved without being affected by these μ changes. It becomes possible to obtain a signal and a reproduction information signal.

In addition, 1li of the guide groove shown in Figs. 3, 4, and 5
Although the IT surface shape is rectangular in all cases, as shown in FIG. 6, during the process of manufacturing a substrate with guide grooves, a tenor arm 61 may occur at the edge of the guide groove. However, it has been experimentally confirmed that the same results as in the previous embodiment can be obtained if the Theno angle θ is within 45°.

Furthermore, similar results can be obtained even if the laser beam is incident on the recording medium from the protective layer side.

Further, the photodetector may detect light transmitted through the recording medium.

Furthermore, it goes without saying that the optical system is not limited to that shown in FIG.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a recording medium equipped with a guide groove, FIG. 2 is a schematic configuration diagram of an optical disk device, FIG. 3 is a configuration diagram of essential parts of an embodiment of the present invention, and FIG. 4 is a photodetector. Figure 5 shows the change in the tracking signal with respect to the center position of the laser beam when the photodetector is in the Fraunhofer region. , FIG. 6 is a diagram showing the main part of another embodiment of the present invention. 1.31... Board, 2.32... Guide groove, 3°33
...Recording layer, 4.34...Protective layer, II...Arrangement medium (optical disc), 12...Mo! 13... Rade oscillator, 14... Optical modulator, 15... Information signal to be recorded, 1g... Lens, II... Polarized light beam sliver, 18... Lens, 19...l/4 wavelength plate, 20...rotating mirror 9-1:II...condensing lens, 22...needle-photodetector, 23...differentiator, J4 (Id *f
)...Tracking signal, 25...Rotating mirror drive unit, 26...Adder, z r (Iada)...
Reproduction information signal, 35゛... Raded light, 3g... Condensing lens, 41゜42... Guide groove work horn, 41.51
- Flat portion within the guide groove, 44.112... Flat portion between the guide grooves. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (4)

[Claims] (1) A recording medium in which a recording layer is formed on a substrate having a guide groove is irradiated with radar light, and the light reflected or transmitted through the recording medium is measured with a photodetector to perform tracking and king while optically transmitting information. In a device that records on and reproduces information from a recording layer, the width of the guide groove and the width between the guide grooves are made larger than the beam diameter of the Radhe light on the recording layer, and the information is transferred onto the edge of the guide groove of the recording layer and the width between the guide grooves. An optical information recording/reproducing device characterized in that recording is performed on at least one of the flat portions within the guide grooves and between the guide grooves. (2) A patent characterized in that the photodetector is comprised of two split photodetectors arranged substantially in parallel in the tracking direction, and tracking is performed so that the difference in output between these two detectors is zero. An optical information recording/reproducing device according to claim 1. (3) The optical information recording and reproducing apparatus according to claim 1 or 2, characterized in that a photodetector is disposed at an imaging position of the recording medium. (4) A photodetector is disposed in the Fraunhofer region of the Rede light reflected or transmitted through the recording medium, and information is recorded in at least one of the flat portions within the guide groove and between the guide grooves. An optical information recording/reproducing apparatus according to claim 1 or 2.