JP2746687B2 - Tracking method and device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking method and apparatus at the time of recording / reproducing in an apparatus for recording / reproducing with a light, for example, a tape-shaped recording medium.

[Summary of the Invention] The present invention relates to an apparatus for recording / reproducing on a tape-shaped recording medium with light, when an optical head is installed in the drum and the drum is rotated to perform recording / reproduction, an extra light spot is formed. Is used to detect the accurate position of the optical head and to quickly and accurately track the light spot based on the detection result, thereby enabling high-speed, high-density recording on a tape-shaped recording medium. .

[Prior Art] Conventionally, there has been no appropriate means for accurately tracking a tape-shaped recording medium, for example.

[Problem to be Solved by the Invention] An optical head is installed in a drum, and the drum is rotated.
When performing recording / reproduction on a tape-shaped recording medium, the time required for the light spot emitted from the optical head to scan the recording medium is a part of the time required for one rotation of the drum. For this reason, when the light spot is located on the recording medium, even if the focus or tracking servo operation is performed, when the light spot is located on a place other than the recording medium, these servo operations cannot be performed. As described above, in an apparatus that performs recording and reproduction by rotating an optical head on a tape-shaped recording medium,
Servo operation cannot be performed continuously. In the case of optical recording,
The recording track width is as narrow as about 1 micron.

Now, when recording / reproducing a symbol by running a tape-shaped recording medium, the fluctuation of the recording / reproducing position reaches several microns. Therefore, even if the light spot starts scanning on the recording medium and the focus and tracking operations are performed, it is difficult to always operate the next track that the light spot scanned last time. For this reason, if optical recording is performed by such an apparatus, overlapping recording or unrecorded areas will appear.

An object of the present invention is to eliminate such a problem and to provide a tracking method and apparatus for accurately scanning a light spot on a next track each time the optical head rotates and starts scanning a recording medium. Is to do. By the way, if such an operation takes a long time, an area that cannot be used as a recording area on a recording medium increases. It is another object of the present invention to provide a quick tracking method and apparatus that minimize the time required for such an operation.

Means for Solving the Problems In order to achieve the above object, the present invention relates to a tape-like optical recording medium that is running and is provided with a plurality of optical heads in a rotating drum that are equally spaced from each other. When the tape-shaped optical recording medium is moved along the tracking guide groove on the tape-shaped optical recording medium, the number required for recording and reproduction and the tape-shaped optical recording between the tape-shaped optical recording medium and the light spot expected at the time of tracking Track identification recorded in a track identification signal recording area of the running tape-shaped optical recording medium using the number of optical heads corresponding to the relative maximum position variation in the running direction of the medium. Reproducing a signal based on a light spot emitted from at least one of the optical heads to the track identification signal recording area;
A relative position change between the tape-shaped optical recording medium and the light spot is detected based on the information of the reproduced track identification signal, and a target of the tape-shaped optical recording medium is set based on the detection result. The optical head closest to the recording track is selected, and recording or reproduction is performed on the target recording track by the selected optical head. A rotary head having a number of optical heads corresponding to the number of recording tracks corresponding to a relative maximum position variation in the running direction of the tape-shaped optical recording medium between the tape-shaped optical recording medium and the light spot. The light spots at equal intervals from the plurality of optical heads irradiated onto the running tape-shaped optical recording medium are used for tracking on the tape-shaped optical recording medium. A rotating head that rotates so as to move along a guide groove; and a track identification signal recorded in a track identification signal recording area of the running tape-shaped optical recording medium, the track identification signal being transmitted from at least one of the optical heads. Means for reproducing based on a light spot irradiated on a recording area, and means for detecting a relative positional change between the tape-shaped optical recording medium and the light spot based on information of the reproduced track identification signal. Means for selecting an optical head closest to a target recording track of the tape-shaped optical recording medium based on the detection result, and performing recording or reproduction on the target recording track by the selected optical head. And characterized in that:

[Operation] According to the present invention, quick and accurate tracking is performed by the above configuration.

Embodiment FIG. 1 shows a tape-shaped optical recording medium used in the present invention. The recording medium 1 is formed by forming an optical recording material on a flexible heat-resistant film by a sputtering method or the like, and tracking guide grooves 2 are formed at regular intervals. A track identification signal is formed in the track identification signal recording area 3 above the area. The signal is recorded in the recording area 4.

FIG. 2 shows a light spot emitted from the optical head onto a recording medium when recording and reproduction are performed simultaneously on six tracks.

The light spots 5 are arranged at the same intervals as the guide grooves 2 formed at regular intervals on the recording medium. The light spot 6 at the end of the recording medium in the traveling direction performs a tracking operation. In the figure, 3
The case where tracking is performed by the beam method is shown. Therefore, although there are three light spots for tracking, these are collectively referred to simply as tracking light spots in the following description.

Assuming that the relative maximum position variation 7 between the recording medium and the light spot during recording and reproduction is ± N track pitches, a light spot emitted from the optical head by adding 2N light spots corresponding to 2N track pitches Set the number. For example, the figure shows a case where the maximum position fluctuation amount 7 is within ± 1 track pitch, and two light spots corresponding to two track pitches are added. Therefore, the number of light spots is six for recording and reproducing signals and two for tracking, for a total of eight.

FIG. 3 shows how the tracking operation of the present invention is performed at the time of recording using the recording medium shown in FIG. 1 and the optical head which emits the light spot shown in FIG.

As shown in FIG. 3, a solid line on the recording medium 1 indicates a recorded area 8 on which recording has already been completed, and a broken line indicates an unrecorded area 9 on which recording has not yet been performed. The traveling of the recording medium 1 is controlled so that the tracking light spot 6 in the light emitted from the optical head is located at the last track position of the recorded area.

The tracking light spot 6 scans from above the recording medium 1. When the light spot is on the recording medium 1, a focusing operation and a tracking operation are performed to reproduce a tracking identification signal. At this time, for example, if the tracking light spot is located on the immediately preceding track due to the relative position change between the recording medium and the light spot, the solid line is determined based on the track identification signal recorded there. The required number of tracks is recorded from the third light spot from the track.

As described above, the present invention increases the number of light spots beyond the number required for recording, and uses the increased light spots for position detection, so that the relative position fluctuation between the recording medium and the light spots can be controlled on the optical head side. Absorption provides a quick and accurate tracking method.

Incidentally, in a rewritable recording system such as magneto-optical recording, the guide groove 2 as shown in FIG. 1 is not always necessary. Instead of the guide groove 2, a track having a magnetization direction opposite to that of the erased state is provided on a recording medium. Is recorded in advance. The track identification signal is recorded magnetically at the same time. In this case, the present invention can be realized without forming the recording guide groove 2 and the track identification signal on the recording medium in advance.

[Effects of the Invention] As described above, according to the present invention, when optical recording or reproduction is performed on a tape-shaped recording medium by rotating an optical head, quick and accurate tracking can be performed. Therefore, an optical recording apparatus using a tape-shaped recording medium is made possible for the first time by the present invention.

[Brief description of the drawings]

FIG. 1 is a diagram showing a tape-shaped optical recording medium used in the present invention, FIG. 2 is a diagram showing a light spot on a recording medium emitted from an optical head, and FIG. FIG. 5 is a diagram illustrating a tracking state according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Tape-shaped recording medium, 2 ... Guide groove for tracking, 3 ... Signal recording area for track identification, 4 ... Recording area, 5 ... Light spot for recording and reproduction, 6 ... Light spot for tracking, 7: maximum position fluctuation amount, 8: recorded area, 9: unrecorded area.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 1-311433 (JP, A) JP-A 63-184961 (JP, A) JP-A 3-41627 (JP, A) JP-A 3- 78117 (JP, A) JP-A-2-306435 (JP, A) JP-A-3-100921 (JP, A)

Claims (2)

(57) [Claims] 1. An optical system according to claim 1, wherein a light spot irradiated from a plurality of optical heads in a rotating drum on the running tape-shaped optical recording medium is moved along a tracking guide groove on the tape-shaped optical recording medium. At the time of recording, the number required for recording and reproduction and the relative maximum position fluctuation in the running direction of the tape-shaped optical recording medium between the tape-shaped optical recording medium and the light spot expected at the time of tracking are equivalent. Using the number of optical heads corresponding to the number of recording tracks to be recorded, the track identification signal recorded in the track identification signal recording area of the running tape-shaped optical recording medium is transmitted from at least one of the optical heads to the track identification signal. Reproducing is performed based on the light spot applied to the recording area, and the distance between the tape-shaped optical recording medium and the light spot is determined based on the information of the reproduced track identification signal. Pairwise position change, and based on the detection result, selects the optical head closest to the target recording track of the tape-shaped optical recording medium, and selects the target recording track by the selected optical head. A recording method for performing recording or reproduction. 2. The number required for recording and reproduction and the relative maximum position fluctuation in the running direction of the tape-shaped optical recording medium between the tape-shaped optical recording medium and the light spot expected at the time of tracking. A rotary head having a number of optical heads corresponding to the number of recording tracks, wherein light spots at equal intervals from a plurality of optical heads irradiated on a running tape-shaped optical recording medium are recorded on the tape-shaped optical recording medium. A rotary head that rotates so as to move along the tracking guide groove on the medium, and a track identification signal recorded in a track identification signal recording area of the running tape-shaped optical recording medium,
Means for reproducing based on a light spot irradiated on the track identification signal recording area from at least one of the optical heads; and a means for reproducing the tape-shaped optical recording medium and the light spot based on information of the reproduced track identification signal. Means for detecting relative positional fluctuation between the optical head and the optical head closest to a target recording track of the tape-shaped optical recording medium based on the detection result, and the optical head is used as the target by the selected optical head. Means for performing recording or reproduction on a recording track.