JPH01125724A - Information recording carrier - Google Patents

Abstract

PURPOSE:To prevent the erroneous detection of an on-track signal on the outside of reference tracks by setting the spacing between the adjacent reference tracks longer than the spacing between the reference tracks and the information part within the same information tracks adjacent to the respective reference tracks. CONSTITUTION:Reference parts C2 consist of the reference tracks Kt disposed on the center lines (a) of the respective tracks Ct. The tracks Kt are formed longer in the spacing A from the adjacent information tracks than the spacing B from a synchronizing part C1 and the spacing B' from a start part C3. Regions N which are separated to the right and left are connected in the case of setting the boundary (m) of 1/2 the spacing B from the respective bit edges of the synchronizing part C1 and the start part C3. The quantity of light in this part is nearly the same and the valley parts generated at both ends of the signal region S2 of the output signal of a line sensor 6 decrease to a negligible level; therefore, the differential signal settles down between reference levels VH and VL. The digital signal of an L level, i.e., off-track detection signal is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information recording carrier for optically recording and reproducing information, and particularly to a sub-track within an information track.

[Prior Art] Conventionally, the forms of information recording carriers used for optically recording and reproducing information include disk-shaped, tape-shaped,
Various types such as card shapes are known. Among these, a record carrier formed in the form of a card (hereinafter referred to as an "optical card") is a record carrier that is easy to manufacture and has good portability (and good accessibility). Development is progressing together with the expression information lj generator.

In such a record carrier, information is recorded in the form of the presence or absence of bits, and in order to read this recorded information, a readout beam is irradiated onto the pit row, and light absorption, reflection, etc. This is done by using an optical sensor to detect changes in the amount of reflected light or transmitted light that change depending on the presence or absence of bits.

FIG. 3 is a schematic block diagram of an optical card ambiguity device, in which an optical head 1 is configured to read information recorded on an optical card C. The optical head l has a light source 2 made of an LED or the like, and focuses the light emitted from the light source 2 onto the information recording surface Cr of the optical card C through an illumination optical system 3. When an LED is used as the light source 2, the light emitting part of the LED usually has a size of about several hundred microns, so this light emitting part can be regarded as a substantially -like surface light source. Therefore, by arranging the light source 2 and the information recording surface Cf appropriately using the optical system 3, the information recording surface Cf of the optical card C can be
A certain area of f (an area containing a plurality of information or information tracks) can be irradiated.

The reflected light from the information recording surface Cf is reflected by a reflection mirror 5 via an imaging optical system 4, and is imaged onto a line sensor 6 made of a COD or the like. The line sensor 6 consists of light-receiving elements arranged parallel to the feeding direction into an electrical signal.

The optical card C moves in the Y direction while being curved in a direction perpendicular to the recording surface Cr by a drive roller 8 and a drive pinch roller 9 connected to a motor 7, and pressers 10 and 11. The line sensor 6 converts reflected light obtained by sequentially scanning (sub-scanning) optical information in the Y direction on the information recording surface Cf into an electrical signal.

FIG. 4 is a schematic plan view showing an example of the recording format of the optical card C, and FIGS. 5 and 6 are enlarged views of the main parts thereof.

In these figures, bands cb are formed in multiple rows in the X direction on the information recording surface Cr on the optical card C.
Each band cb is a large number of information tracks C arranged in the Y direction.
It consists of t. Each information track Ct is several tens to one
It has information on the order of tens of bits, and as shown in FIG. 5, it is composed of a synchronization section C1, a reference section C2, a start section C3, and a data section C4.

The reference section C2 is composed of a narrow reference track Kt arranged on the center line a of each track Ct in order to separate and identify each information track Ct arranged in the Y direction. Used to obtain on-track information for playback.

Next, how to determine on-track from the IM raw signal will be explained.

7 and 8 are waveform diagrams of reproduced signals when a light spot scans on line a (on-track) in FIG. 6 and on line b (off-track) in FIG. 6. In both figures, the waveforms of signal regions S1, S2 and S3 are:
They correspond to the synchronization section CI, reference section C2, and start section C3, respectively, and Figure (A) shows the line sensor 6.
The positive level corresponds to the bit part (the shaded part in FIG. 6), and the negative level corresponds to the part other than the bit part. Also, Figure (B) is a signal obtained by differentiating the output signal of Figure (A), and Figure (C) is a digital signal obtained by converting this differentiated signal into a binary value through a comparator with hysteresis, and the level V shown in Figure (B). and Vt, are the comparison levels of the comparators.

As is clear from both figures, when on-track, the digital signal corresponding to the reference section C2 remains "1" for a certain period of time.
1" level (Fig. 7C), and when off-track, it becomes "
L,'' level (Fig. 8C). Therefore, the state of this digital signal may be detected to determine whether or not it is on track, and the data portion C4 may be reproduced.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, the same digital signal as on-track may be output while moving from one information track to the next information track.

FIG. 9 is a waveform diagram showing such a state, in which valleys occur at both ends of the region S2 of the output signal (see figure), and therefore the differential signal exceeds the comparison levels vH and VL at both ends of the region S2. (Figure B), and the same digital signal as on-track is output (Figure C).

In such a state, no on-track detection signal is output even while moving from one track to the next, making it impossible to detect that the track has changed.

If this happens, a burst error will occur in which all the data for the information track is lost, resulting in a significant drop in the error rate.

The cause of this will be explained with reference to FIG. 1θ and FIG. 11.

Similar to FIG. 6, FIG. 10 is an enlarged view of the main parts centering on the reference part C2, and is shown with the X-Y axes rotated by 90 degrees with respect to FIG. Further, FIG. 11 shows the output h of the line sensor 6 when on-track.

If the bit size is sufficiently large and the optical characteristics of the imaging optical system 4 are ideally configured, the output signal of the line sensor becomes a rectangular wave as shown by the solid line. However, the bit size formed on the optical card C is actually from a few tens of microns to several tens of microns, and the bit functions similarly to a diffraction grating, and even if the optical card C moves up and down to some extent, Since the NA (lens numerical aperture) is made small in order to increase the depth of focus of the imaging optical system 4 so that the image can be read, the resolving power of the imaging optical system 4 itself also decreases. 1st
The dotted line in FIG. 1 shows the output signal from such an actual line sensor 6.

The signal waveform of each bit is blunted into a sinusoidal waveform, and the peak output itself is low in portions where the bit length is shorter than the reference portion C2, such as the synchronization portion C1 and the start portion C3.

Such a change in the signal waveform depends on the distance from the bit edge, and if the boundary m is set with a dimension of 1/2 of the distance between bits from each bit as shown in the single note diagram, the bit If we assume that the area (hatched area in the figure) has a low reflectance and the other areas have a high reflectance, the area N surrounded by the boundary m will have a larger amount of light than other areas on the line sensor 6, as shown in FIG. 9(A). As shown in the figure, a valley will be produced in the output signal.

Since the signal reproducing circuit obtains a digital signal from a signal obtained by differentiating the output signal of the line sensor 6 in order to eliminate the influence of shading of the light source 2, the DC level is not affected by the valley as shown in FIG. 9(A). Even if the line shifts downward, a digital signal similar to that when the reference line is detected when on-track is output as shown in FIG. 2(C).

The above explanation is based on the just-focus state, but this tendency is exacerbated when defocusing occurs even within the depth of focus.

[Means for Solving the Problems] The information recording carrier according to the present invention has been made to solve the above problems, and includes a plurality of information tracks arranged in the direction in which information is arranged on the information tracks and in the direction in which the information is arranged. arranged in substantially orthogonal directions, each information track having an identification area for separating and identifying the information track from other adjacent information tracks, and the width of the area in the substantially orthogonal direction An information recording carrier having a width narrower than the width of the information track in the substantially orthogonal direction, wherein an interval between patterns indicating +in identification areas adjacent in the substantially orthogonal direction is set between the pattern indicating the identification area and the pattern. It is characterized in that the distance between the pattern and other patterns adjacent to each other in the information arrangement direction is longer than that of the other pattern.

[Operation] According to the present invention, by making the interval between adjacent reference tracks longer than the interval between the reference track and the information recording part (synchronization part, start part) in the same information track adjacent to each reference track, , to prevent erroneous detection of on-track signals outside the reference track.

〔Example] Embodiments of the F1 invention will now be described with reference to the drawings.

FIG. 1 and FIG. 2 are an enlarged view of a main part showing an embodiment of an information recording carrier according to the present invention, and a waveform diagram showing an iQ raw signal thereof.

In FIG. 1, each information track Ct is composed of a synchronization section C11, a reference section C2, a start section C3, and a data section C4 arranged in the X direction on the track center line a, and these information tracks are arranged in multiple rows in the X direction. Arranged.

The reference section C2 is for separating and identifying any information track from adjacent information tracks, and is a reference track KL arranged on the center IQa of each track CL.
This track KL has an interval B with respect to the adjacent information track, an interval B with the synchronization part C1, and a start part C.
3 and interval B.

It is formed longer. Therefore, if a boundary m that is 1/2 of the interval B is set from each pit edge of the synchronization part CI and the start part C3, the area N that was separated left and right in FIG. 10 will be connected as shown in FIG. , this part has almost the same amount of light.

Therefore, as shown in FIG. 2(A), the valleys occurring at both ends of the signal region S2 of the output signal of the line sensor 6 are reduced to a negligible level, and therefore the differential signal is lowered to the comparison level v, l.
and VL (FIG. 2B), and it is possible to obtain a 1-level digital signal, that is, an off-track detection signal (FIG. 2C).

[Effects of the Invention] As described above in detail, according to the information recording carrier according to the present invention, the interval between a reference track in an arbitrary information track and a reference track in an adjacent information track is determined based on the information arrangement in the information track. By making the interval longer than the distance between adjacent information recording sections in the direction, it is effective to prevent Xi detection of an on-track signal outside the reference track and to stably detect track transition. This eliminates burst errors where all data for one track is lost,
It becomes possible to improve the error rate.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of essential parts of an embodiment of an information recording carrier according to the present invention. Fig. 2 is a waveform diagram showing the endogenous signal of the information track in Fig. 1, Fig. 3 is a schematic configuration diagram of an optical card reproducing device, and Fig. 4 is an example of the information recording format of the optical card. FIGS. 5 and 6 are enlarged views of main parts showing conventional information tracks of an optical card; FIGS. 7 to 9 are waveform diagrams showing reproduction signals of conventional information tracks; FIG. 10 is an enlarged view of the main part for explaining the problems of the conventional information track, and FIG. 11 is a waveform diagram showing the reproduced signal of FIG. C...Optical card Cf...Information recording carrier information CI...Synchronization section C2...Reference section C3...Start section C4...Data section Kt...Reference track

Claims (1)

[Claims] (1) A plurality of information tracks are arranged in the direction in which information is arranged on the information tracks and in a direction substantially perpendicular to the direction, and each information track separates and identifies the information track from other adjacent information tracks. an information recording carrier having an identification area for identifying information, the width of the area in the substantially orthogonal direction being narrower than the width of the information track in the substantially orthogonal direction, the information recording carrier being adjacent to the information track in the substantially orthogonal direction; An information recording carrier characterized in that an interval between patterns indicating the identification area is longer than an interval between the pattern indicating the identification area and another pattern adjacent to the pattern in the information arrangement direction.