JPH07122964B2 - Information playback device - Google Patents

Description

The present invention relates to an information reproducing apparatus, and is particularly applied to reproducing information from a recording track formed by scanning a head so as to traverse the traveling direction of a recording medium. Is suitable.

B. Summary of the Invention The present invention is an information reproducing apparatus in which a large number of recording tracks are formed in a direction traversing the traveling direction of a recording medium, in a state where the scanning direction of the reproducing head means is deviated from the recording track. Also, by positioning a plurality of head elements so that all the recorded information on each recording track can be reproduced by the reproducing head means, the mounting accuracy of the reproducing head means for the recording track can be further eased.

C Conventional Technology As a conventional information recording / reproducing apparatus, as shown in FIG. 8, a recording light spot 2 made of, for example, a laser beam is formed on a tape-shaped optical recording medium 1 in a direction b crossing a running direction a thereof. It is considered that the recording track TR is formed by scanning.

Here, the diameter of the recording light spot 2 is, for example, 1 [μm].
Can be converged to a certain degree (for example, wavelength 780 [n
m) when using the laser light). Therefore, if a large number of recording tracks TR are formed so as to be connected to each other in a guard bandless manner as shown in FIG. 9 and the optical information can be reproduced from each recording track, the optical information can be more densely recorded. It is considered possible to record and reproduce.

D The problem to be solved by the invention D However, when the recording track TR is recorded at high density in this way, the scanning direction c of the laser light beam for forming the reproduction optical spot 3 on the optical recording medium 1 during reproduction is If deviated by the angle Δα, the reproduction light spot 3 may not be able to scan the center scanning locus TR _SCN of the recording track TR.

In order to solve this problem, it is necessary to strictly control the mounting accuracy of the reproducing head means so that the angular deviation Δα does not occur. It was difficult to obtain a playback device.

Incidentally, when the length of the recording track TR is set to about 1 [mm], the offset amount Δx from the recording track TR of the reproducing optical spot 3 is set within the range of Δx = + 0.1 [μm]. To achieve this, the mounting angle error Δα of the optical scanning system is Therefore, it is necessary to control the mounting angle with an extremely high accuracy of about ± 20.6 ″ so that it can be obtained by

In practice, it is difficult to obtain an angle servo mechanism that corrects the angle of the reproducing optical spot 3 under such conditions, and if a reproducing method that does not strictly require the accuracy of the mounting angle can be used. It is considered that the structure of the reproducing device can be further simplified.

The present invention has been made in consideration of the above points, and, for example, information for surely reproducing the information on the recording track even if the scanning locus of the reproducing optical spot deviates from the recording track by an angle. It is intended to propose a recording / reproducing device.

E Means for Solving the Problems In order to solve the problems, according to the present invention, an information reproducing apparatus for reproducing recorded information from a recording medium 1 in which a large number of recording tracks TR are sequentially arranged in a direction crossing the traveling direction. In the recording track TR, digital recording information to which address data is added for each predetermined data group is recorded, and by scanning the recording medium 1 by a plurality of reproducing head elements 3A and 3B, Head element for each reproduction
Digital recording information is picked up from a single recording track TR among the recording tracks TR by 3A and 3B and written in the memory means 15 based on the address data, and the scanning trace of the reproducing head elements 3A and 3B is recorded. When the angle is deviated from the TR, the reproducing head elements 3A and 3B scan different areas on each recording track TR, and the memory means
The reproduction signal is obtained by reading the digital recording information from 15 based on the address data.

F-action When there is an angular deviation in the scanning direction of the reproducing head means 11 with respect to the recording track TR on the recording medium 1, a plurality of head elements 3A and 3B constituting the reproducing head means 11 make each recording track TR oblique. Since it is possible to scan all the recording areas of one track while traversing the track, it is possible to carry out the pick-up reproduction without the recording information recorded in the recording track TR running out.

Thus, the reproducing head element 3A for the recording track TR,
It is possible to realize an information recording / reproducing device having a simple configuration that can reliably reproduce recorded information without managing the mounting accuracy of 3B to a very high value.

G Embodiment One embodiment of the present invention will be described in detail below with reference to the drawings.

(G1) Embodiment In FIG. 2 in which parts corresponding to those in FIG. 8 are assigned the same reference numerals, the recording optical spot 2 for scanning the optical recording medium 1 at the time of recording is arranged in the scanning direction of the optical recording medium 1. It is formed in an elliptical shape having a major axis in the direction of a.
[Μm], and the length of the minor axis in the scanning direction a is selected to be 1.0 [μm].

Thus, the track pitch is 1.6 μ on the optical recording medium 1.
m], a large number of recording tracks TR are formed so as to be connected in a guard bandless manner.

The information recorded on the recording track TR is composed of digital data in which logical signals are sequentially arranged in the scanning direction b, divided into data groups by a predetermined amount of information, and each data group is addressed. By adding and recording data and designating the address data, data processing can be performed with one data group as one unit.

The reproducing light spot 3 is generated by an optical system constituting the reproducing head means and has a plurality of, for example, two light spots 3A and 3B as shown in FIG. Each light spot
3A and 3B are formed in a circular shape having a diameter smaller than the track width x _W (= track pitch x _P ) of the recording track TR.

The two optical spots 3A and 3B are subjected to tracking control so that the recording tracks successively connected can be scanned one track at a time. In this tracking state, when one of the optical spots 3A enters the recording track TR, an off-track amount x _A is, for example, in the direction opposite to the traveling direction a of the optical recording medium 1 with respect to the center line CET of the recording track TR. The optical spot 3B is positioned so as to be in an off-track position, while the other optical spot 3B is in an off-track amount x _{B in} the traveling direction a of the optical recording medium 1 from the center line CET of the recording track TR. Is positioned as.

Thus, the optical spots 3A and 3B are 1 track pitch x
Scanning is performed in parallel with each other in the direction b crossing the traveling direction a while maintaining an interval corresponding to the sum of _P and the off-track amounts x _A and x _B.

As a result, when the mounting position of the reproducing head means is not angularly displaced with respect to the recording track TR (when Δα = 0), the optical spots 3A and 3B are along the extension direction of the recording track TR as shown in FIG. By scanning in the direction b,
Recording information can be picked up from the corresponding recording track TR.

On the other hand, when the reproducing head means is mounted at a mounting position where there is an angular deviation with respect to the recording track TR, as shown in FIG. 4, the pair of optical spots 3A and 3B move the recording track TR. Scanning is performed in the direction b which is diagonally traversed, and the recording information recorded on the recording track TR thus traversed is picked up by the optical spots 3A and 3B.

In the case of this embodiment, as shown in FIG. 5, the optical spots 3A and 3B are transmitted from the optical head elements 11A and 11B provided as head elements in the optical head 11 constituting the reproducing head means, for example, The reflected light is transmitted to the optical head elements 11A and 1A.
It is converted to electrical pick-up signals SA ₁ and SB ₁ by a photoelectric converter provided in 1B.

The pick-up signals SA ₁ and SB ₁ are sent to digital data detection circuits via buffer amplifier circuits 12A and 12B, respectively.
It is input to 13A and 13B and converted into digital data SA ₂ and SB ₂ .

The digital data SA ₂ and SB ₂ are stored in the error processing circuit 14A.
And 14B, the error judgment is performed and the error correction is executed in units of the data group picked up from the recording track TR. Thus, the error-processed reproduction data SA ₃ and SB ₃ from the error processing circuits 14A and 14B are input to the control memory 15 together with the error determination signals SA ₄ and SB ₄ .

The reproduction data SA ₃ and SB ₃ have address data for each unit data group, and the control memory 15 corresponds to the address data for which the error determination signals SA ₄ and SB ₄ have not determined that an error has occurred. Write the reproduction data SA ₃ and SB ₃ to the memory area to be used.

Thus, the control memory 15 does not accept the reproduction data having no error even if the reproduction data having the same address data arrives again when the reproduction data having no error is stored in one memory area.

The reproduction data written in the control memory 15 in this manner is read out as output data DATA in a predetermined order and at a predetermined timing.

In the above configuration, as described above with reference to FIG.
If the optical system of the optical head 11 does not have an angular deviation with respect to the recording track TR, the optical spot 3A is located at the position ... 3A _-2 , 3A _-1 ,
3A ₀ , 3A ₊₁ , 3A ₊₂ …… Sequential recording track TR (…… TR
_-2 , TR _-1 , TR ₀ , TR ₊₁ , TR ₊₂ ......), scans, and reproduces data SA obtained from the error processing circuit 14A from each recording track based on the pick-up signal SA _{1. 3} is written in the control memory 15 and goes.

At this time, the optical spot 3A scans the recording tracks TR without traversing the recording tracks TR, so that reproduced data having no error can be surely obtained.

At the same time, the other optical spot 3B trails the optical spot 3A by a distance corresponding to the track pitch x _P + the off-track amount x _A + the off-track amount x _B ... 3B _-3 , 3B _-2 ,
3B _-1 , 3B ₀ , 3B ₊₁ ... sequentially recording track TR (... TR
_-3 , TR _-2 , TR _-1 , TR ₀ , TR ₊₁ ...), and scans, and in the error processing circuit 14B also based on the pick-up signal SB ₁ obtained from the optical head element 11B. It is possible to obtain the reproduced data SB ₃ having no error. However, at this time, since the correct reproduction data SA ₃ is written in the control memory 15 by the pick-up signal SA ₁ already obtained based on the preceding optical spot 3A, the reproduction data SB ₃ obtained at a later time is stored. It is controlled so that it will not be accepted.

On the other hand, as described above with reference to FIG.
When the optical system 11 is attached at a position deviated from the recording track TR by an angle, the optical spots 3A and 3B are in a state of repeating scanning while crossing a plurality of recording tracks.

In the case of the embodiment shown in FIG. 4, the optical spots 3A are sequentially ... 3A _-2 ,
_{3A -1, 3A 0, 3A +1} , recording the position of the 3A ₊₂ ...... track TR
(…… TR _-2 , TR _-1 , TR ₀ , TR ₊₁ , TR ₊₂ ......} plunges into the track, but due to the angular misalignment, the next track TR
(... TR _-1 , TR ₀ , TR _{+ 1} , TR ₊₂ , TR ₊₃ ...} scan diagonally across.

At the same time, the other optical spot 3B does the same ... 3
_{B -3, 3B -2, 3B -1} , 3B 0, 3B +1 sequentially recorded from the position of entry of the ...... track _{TR (...... TR -3, TR -2} , TR -1, TR 0, TR +1 ...
...).

However, the plunging positions of the optical spots 3A and 3B are, as described above with reference to FIG. 1, offset by the off-track amounts x _A and x _{B in the} direction opposite to the traveling direction a of the optical recording medium 1 and in the same direction, respectively. Optical spots 3A and 3B
As a whole, the optical information recorded in one recording track can be picked up without running out.

For example, as shown in FIG. 6, and try to focus on the track TR _0, and the light Supotsuto 3A for this track TR ₀ which has entered sequentially rush position 3A _-1, light enters the rush position 3A ₀ and 3B ₀ Spots 3A and 3B, and an optical spot plunging into plunge position 3B ₊₁
3B sequentially scans the recording track TR ₀ diagonally.

However, the scanning position of each optical spot scans different areas on the track TR ₀ with a slight shift, and as a whole, all the optical information recorded on the recording track TR ₀ can be picked up while sequentially shifting the time. become.

Since the optical information picked up by the optical spots 3A and 3B forms significant information on a data group basis, the optical spots 3A or 3B are used as recording tracks TR _0.
When scanning upward, even if crosstalk occurs from a recording track adjacent to the recording track TR ₀ , for example, the crosstalk can maintain a bit error rate to the extent that no error is detected in the error processing circuit 14A or 14B. In this case, the pick-up signal obtained from either the optical spot 3A or 3B can be written in the control memory 15.

According to the above configuration, even in the reproducing apparatus in which the reproducing head means is attached at a position having an angular deviation with respect to the recording track TR of the optical recording medium 1, the optical recording medium 1
It is possible to surely reproduce the recorded information recorded in the above.

This means that when a recording medium recorded by a different information recording device is reproduced by another information reproducing device (when information is recorded and reproduced by a so-called compatible device), the information reproducing device This means that the recorded information can be reliably reproduced even if the position accuracy of the reproducing head means is even lower, and accordingly, the structure of the information reproducing apparatus can be simplified because the servo system for correcting the angle deviation is unnecessary.

(G2) Other Embodiments (1) In the above embodiment, the case where the number of the reproducing optical spots is selected is two. However, the present invention is not limited to this, and two or more may be selected as necessary. An optical spot may be used.

(2) In addition to the above-mentioned embodiment, for example, as shown in FIG. 7, recording tracks TR (... TR _-2 , TR _-1 , TR ₀ , TR ₊₁ , TR
₊₂ ......) for the tracking pilot signal PL for tracking
By superimposing recording _1, PL _2, if configured to tracking the recording track TR corresponding to the reproducing light Supotsuto easily by using the tracking signal, the reproducing light Supotsuto is greater too the recording track TR Since there is no danger of coming off, the recorded information can be reliably picked up.

(3) In the above-mentioned embodiments, the present invention is applied to the case where the recorded information on the optical recording medium is reproduced. However, the present invention is not limited to this. For example, the recorded information on the magnetic recording medium is reproduced. The present invention can be widely applied to the case of reproducing using a magnetic head as a recording head means. The point is that a large number of recording tracks are recorded on a recording medium by forming the recording tracks in a direction transverse to the traveling direction of the recording medium. It can be widely applied to an information reproducing device formed so as to be arranged along the traveling direction.

(4) In the above-mentioned embodiment, the embodiment in which the recording information is reproduced from the recording medium in which the recording track is formed in a guard bandless manner has been described. The same effect as can be obtained.

(5) In the above embodiment, the case where the number of reproduction light spots is two is described, but the number is not limited to this and may be three or more.

Incidentally, if the number of reproducing optical spots is increased, the diameter of each optical spot can be reduced, so that the crosstalk amount from the adjacent track can be reduced.

H Effect of the Invention As described above, according to the present invention, when a plurality of reproducing head elements are provided and the scanning loci of the plurality of reproducing head elements with respect to the recording track are deviated in angle, each reproducing head element is By arranging so that different areas of the recording track are scanned, a simple information reproduction that can reliably reproduce high-density recorded information even if the positional accuracy of the angular displacement of the reproducing head element with respect to the recording track is not so high The device can be easily realized.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the construction of a reproducing head means in an embodiment of an information reproducing apparatus according to the present invention, and FIG. 2 is a schematic diagram showing the construction of the recording head means, FIGS. FIG. 5 is a schematic diagram showing a scanning mode of the reproducing light beam, FIG. 5 is a block diagram showing a concrete structure of the reproducing system, and FIG. 6 is a schematic diagram showing a scanning mode of one recording track TR ₀ in detail. FIG. 7 is a schematic diagram showing another embodiment of the present invention, FIG. 8 is a schematic diagram for explaining the angular deviation of the reproducing head means, and FIG. 9 is a schematic diagram showing the structure of the recording track. Is. 1 ... Optical recording medium, 2 ... Recording optical spot, 3 ... Reproducing optical spot, 11 ... Optical head, 12A, 12B ... Input circuit, 13A, 13B ... Digital data detection circuit, 14A, 14B
…… Error processing circuit, 15 …… Control memory, TR
(TR _{-2 to} TR _{0 to} TR ₊₂ ) ... Recording track, 3A _{-2 to} 3A _{0 to} 3A
₊₂ , 3B _{-1 to} 3B _{0 to} 3B ₊₃ …… The entry position of the playback optical spot.

Claims (1)

[Claims] 1. An information reproducing apparatus for reproducing recorded information from a recording medium in which a large number of recording tracks are sequentially arranged in a direction traversing a traveling direction, wherein each recording track is provided with address data for each predetermined data group. The digital recording information is recorded, and the recording head is scanned by a plurality of reproducing head elements to scan the recording medium from a single recording track among the recording tracks. The recording information is picked up and written in the memory means on the basis of the address data, and when the scanning locus of the reproducing head element is angularly displaced with respect to the recording track, the reproducing head element is arranged on the recording track. The different areas are scanned, and the digital data is read from the memory means based on the address data. The information reproducing apparatus is characterized in that to obtain a reproduced signal by reading the recording information.