JPS60121550A - Optical information recording carrier - Google Patents

Abstract

PURPOSE:To obtain an optical information recording carrier with which the track jump is not easily produced and also the reproduction signal fed from an uneven signal part can be satisfactorily detected, by increasing the width of a tracking track and decreasing the pit width of said uneven signal part. CONSTITUTION:Convex tracks 22 are provided on the surfasce of a base material 21 with prescribed pitches, and a recording material layer 23 is formed on the surface of the tracks 22. The area where the tracks 22 are provided comprises an area 3 of a tracking track part 24 and an area 4 of an uneven signal part. The groove width 29 of the part 24 is larger than the groove width 30 of a pit 26 of the uneven signal part. While the groove depth 25 of the part 24 is equal to the groove depth 27 of the pit 26. The track depth is set so that the length of an optical path is equal to about 1/8 wavelength of a light beam. In such a constitution, it is possible to obtain a tracking control system which has a reduced number of track jumps to the disturbances like vibrations, impacts, etc. Furthermore it is possible to detect satisfactorily the reproduction signal fed from the uneven signal part and recorded in an uneven pit like an address, sector, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical information record carrier (hereinafter simply referred to as record carrier) that records signals using a light source such as a semiconductor laser.

Conventional Structure and Problems Record carriers used in optical recording and reproducing devices are formed by forming tracks in the form of concave or convex stripes on the surface of a base material in advance, and then depositing a recording material layer on the surface of the base material. Those formed by means are used. The uneven track on the surface of the base material includes a tracking track section for tracking a light beam to record a signal on the recording material layer or for reproducing a signal recorded on the recording material layer, and a unit track or In order to identify a tracking track, a signal such as an address or a sector is combined with a concavo-convex signal section recorded as a concave-convex pit string. The track depth dO is set so that the refractive index of the base material is no and the wavelength of the light beam is λ0, so that the optical path length nodo is nodo - λ0/8, and the width of the tracking track part and the bit of the uneven signal part. The widths are the same. The trunk width is set to such a width that a positional deviation between the light beam and the track, that is, a tracking control signal, can be detected, and a signal from the uneven signal section can be detected. Regarding the relationship between the tracking control for controlling the light beam to scan over the track and the track width, the wider the track width, the stronger the control system can be constructed in which track skipping does not occur in response to disturbances such as vibrations or shocks. However, in conventional record carriers, as the track width increases, the S/N of the reproduced signal from the uneven signal section decreases, so the track width is set to a width that allows both the reproduced signal from the uneven signal section and the tracking control signal to be detected to some extent. It was set.

Therefore, when a conventional record carrier is loaded into an optical recording/reproducing device and recorded/reproduced, track skipping is likely to occur if vibration or reconnaissance is applied to the device from the outside, and the reproduced signal from the uneven signal section is also unstable. could not be detected.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a record carrier that eliminates the above-mentioned conventional drawbacks, allows a control system to be constructed that is strong against external vibrations or shocks, and that also allows good detection of reproduced signals from the uneven signal portion. The record carrier of the present invention has the following features: the tracking track portion has a wide width;
The bit width of the concave-convex signal portion is narrowed to prevent track skipping from occurring, and the reproduced signal from the concave-convex signal portion can also be detected satisfactorily.

Description of examples The present invention will be described in detail below with reference to the drawings.

It should be noted that the same reference numerals are used for the same parts in the description of the drawings.

FIG. 1 shows an embodiment of the recording medium of the present invention, in which a recording carrier 1 has a mounting hole 2 in the center. Record carrier 1
The trunk is concentrically shaped, and the region where the same circular trunk is provided is composed of a region 3 of a tracking track portion and a region 4 of a concavo-convex signal portion.

FIG. 2 shows an enlarged cross-sectional view of region 5 indicated by broken lines in FIG. 1.

Tracks 22 in the form of convex stripes are provided at a predetermined pitch on the surface of the base material 21, and a recording material layer 23 is formed on the surface of the base material 21.
is provided. The area where the tracks are provided is composed of the area 3 of the tracking track section and the area 4 of the uneven signal section, and the groove depth 26 of the tracking track section 24 shown by diagonal lines and the bit 26 of the uneven signal section are shown by diagonal lines. The groove depths 27 are equal, and if the refractive index of the base material is no, the groove depth is do, and the wavelength of the light beam is λ0, then the groove depth dO is do=λ'/'an.

The track direction of the concentric tracks 22 is the direction of the arrow 28, and the groove width 29 of the tracking track portion is
is made wider by the groove width of the pit 26 of the concavo-convex signal portion. As mentioned above, the signals are indicated by diagonal lines and are recorded on the tracking track section 24.An optical recording/reproducing apparatus using the record carrier of the present invention will be described with reference to FIG.

The record carrier 1 is rotated by a rotating shaft of a disk motor 41 at a predetermined number of rotations. A light beam 43 generated from a light source 42 such as a semi-interceptor laser is converted into parallel light by a coupling lens 44, and then sent to a polarizing beam splitter 46.
and A wavelength plate 46 , is reflected by a reflecting mirror 47 , and is focused onto the record carrier 1 by a converging lens 48 . The original beam 43 reflected from the record carrier 1 passes through the converging lens 48 again.
, is reflected by a reflecting mirror 47 , passes through an A wavelength plate 46 , is reflected by a polarizing beam splinter 46 , and is irradiated onto a photodetector 49 . The photodetector 49 has a two-part structure, and the direction of the dividing line is the track direction on the photodetector 49.

The two outputs of the photodetector 49 are respectively input to a differential amplifier 50, and the differential amplifier 6Q outputs the difference between the two human power signals. It is well known that the signal represents the positional deviation of the trunk, that is, the tracking control signal, and will not be described in detail.

The signal from the differential amplifier 60 is sent to a phase compensation circuit 51 for compensating the phase of the tracking control system, and a drive circuit 6 for power amplification.
2 to the tracking element 63. The converging lens 48 is attached to a tracking element 63, and the tracking element 63 connects the converging lens 48 to the record carrier 1.
It is configured to be able to move in a direction perpendicular to the upper track direction.

Therefore, the converging lens 4 moves according to the signal from the differential amplifier 50, and tracking control is performed so that the light beam 43 on the record carrier 1 always scans the track.

To explain the signal detection of the uneven signal section, the photodetector 4
The two outputs of 9 are respectively input to a combining circuit 64, and the combining circuit 64 outputs a signal obtained by combining both signals.Although not shown in the drawing, the signal of the combining circuit 54 is processed and the address is determined. has obtained information on sectors, etc.

When recording a signal, first, the track area in which the signal is to be recorded is confirmed from information such as an address or sector, and the intensity of the original beam 40 is changed in accordance with the signal to be recorded.

The relationship between the pit shape of the concavo-convex signal portion and the signal of the combining circuit 64 will be explained with reference to FIG. 4. 4(a) shows the light beam 43 and the narrow pit 26 on the record carrier 1, and FIG. 4(b) shows the composition circuit 64 when the original beam 43 scans over the bit 26 in FIG. 4(a). Shows the signal waveform.

(0) and (d) are explanatory diagrams when the width of the pit 26 is wide. (0) shows the light beam 43 and wide pits 63 and 64, and (d) shows the combining circuit 54 when the light beam 43 scans over the pits 63 and 64 in (Q).
The signal waveform is shown. Comparing (b) and (d), when the bit width is narrow, good signals can be obtained with long pits like 61 or short pits like 62, but when the bit width is wide, It can be seen that long pits such as 63 degrade signal quality and become difficult to detect.

The reproduction signal from the concavo-convex signal portion is obtained because the light beam is diffracted at the edge of the pit, and the narrower the width, the better the signal can be obtained.

The relationship between track width and tracking signal will be explained with reference to FIG. 6. FIG. 6 (!L) shows the relationship between the light beam 43 and the track 22, (0 indicates the direction perpendicular to the track direction in (e), that is, the arrow 7
1 shows a signal waveform of the differential amplifier 50 when it is moved in one direction. If the width of the track 22 is wide, there will be four waveforms as shown by the curve 72, and the waveform will be 7 as shown by the broken line in FIG. 6(a).
When the track width is narrow as in No. 3, the waveform becomes a curve 74 shown by a broken line in FIG. 5(b). The ranges of the points where the signal output reaches the maximum value and the minimum value on the curves 72 and 73 are indicated by 75 and 76, respectively, and the wider the track width, the wider the range. Therefore, if the loop gain of the tracking control system is constant, the wider the range, the stronger the resistance to disturbance.

In the record carrier of the present invention, it seems that track skipping is likely to occur because the bit width of the uneven signal area is narrow, but in reality, the time it takes for the original beam to scan over the uneven signal area is very short. It is about several tens of microseconds, and there is no problem even if the bit width is narrowed.

Effects of the Invention The present invention has been described in detail above. By using the optical information recording carrier of the present invention, it is possible to configure a tracking control system with less track skipping due to disturbances such as vibration or assault, and Alternatively, a reproduced signal from a concavo-convex signal portion recorded with concave-convex pits such as sectors can also be detected satisfactorily.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an actual example of the optical information recording carrier of the present invention, Fig. 2 is an enlarged perspective view of a portion of Fig. 1, and Fig. 3 is a use of the optical information recording carrier of the present invention. FIG. 4 is an explanatory diagram of the relationship between the optical beam on the optical information recording carrier and the bit width, and FIG. 5 is a block diagram showing the relationship between the optical beam on the optical information recording carrier and the bit width. 0 1...Record carrier, 3...Tracking track area, 4...Concave/convex signal area, 22...
... Trunk, 23 ... Recording material layer, 24
...Pursuit track section, 26...Depth of pursuit track section, 26...Focus, 27...
...Pit depth, 28...Track direction,
29... Width of tracking track section, 30...
- Pit width. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 70 Figure 5

Claims (2)

[Claims] (1) A track is formed by a concave or convex tracking track portion for tracking a light beam, and a concave and convex signal portion made of a concave and convex bit agent provided for identifying the tracking track, and at least An optical information recording carrier in which a signal is recorded on the tracking track section, wherein the width of the tracking trunk section is wider than the width of the pit of the uneven signal section. (2) The track depth and optical path length are approximately μ of the wavelength of the light beam.
Claim 1 characterized in that
The optical information recording carrier described in Section 3.