Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
2001-08-30
2003-05-06
Neyzari, Ali (Department: 2655)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
C369S030150, C369S032010, C369S044280
Reexamination Certificate
active
06560170
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a track search control apparatus, track search control method, data recording apparatus, data reproduction apparatus and data recording medium, and more particularly to a track search control apparatus and track search control method of jumping over a plurality of tracks in searching for a target track; a data recording apparatus and data reproduction apparatus that contains the track search control apparatus; and a data recording medium, on which a track search control program for controlling the track search operation is recorded and which is readable by a computer.
2. Description of the Related Art
Generally, in the case of reproducing data from a recording medium such as an optical disk on which data are recorded on tracks, when reproduction of that data is temporarily paused to start reproduction of other data specified by the user, it is necessary to move, within a short period of time, the optical spot from the position of the track where the currently detected data are recorded to the position on the recording medium of the target track, or the track where the other data to be detected are recorded. Moving this optical spot to the target track will hereafter be called a track jump.
Conventionally, when controlling the track jump, the number of tracks (hereafter called the first number of tracks) between the track where the currently detected data are recorded (hereafter called the first track) and the end of the lead-in area on the optical disk, is found based on identification data (for example the address of data corresponding to the first track), which indicates the first track. Then, the number of tracks (hereafter called the second number of tracks) between the track where the other data are recorded (hereafter called the second track) and the end of the lead-in area on the optical disk, is found based on identification data (for example the address of data corresponding to the second track), which indicates the second track. Further, the number of tracks to be jumped was calculated from the difference between the first number of tracks and second number of tracks. Finally, control for jumping tracks to the target track is executed while detecting the number of tracks already jumped according to the change in the light beam for data reproduction that is reflected from each track.
When finding the first number of tracks and second number of tracks, the identification data is used as an aid in searching for the track in question from a table in which the relationship between each track and the number of tracks between each track and the end of the lead-in area are stored beforehand, and based on this, the first number of tracks or second number of tracks, is found.
Conventionally, this table was created by taking the average value of the number of tracks (this is the number of tracks between each track and the end of the lead-in area, and the value may vary due to the position on the optical disk due to unevenness) that was obtained by considering the unevenness of the track pitch, which is the spacing between pairs of adjacent track on the optical disk, or actual track movement due to rotation of the disk, so even though the total number of tracks already jumped during track jumping is accurately calculated, the original number of tracks (number of tracks stored in memory as the table) used for calculating the target number of tracks to jump during that track jump may differ from the actual number. Therefore, it is possible that the optical spot will not accurately reach the second track position. When the second track is near the end on the outer side of the optical disk, there is a possibility that the second track will also be jumped over during the track jump and that the optical spot will move to an area on the outer side of the disk where no data are recorded, and then it becomes impossible to control the optical spot after that.
Moreover, even if the optical spot does not reach the area on the outer side of the optical disk where no data are recorded, there is also the possibility that in the case of an optical disk on which data are recorded in order starting from the inside, the optical spot may reach the area on the inside where no data are recorded, and this will also result in position control being lost.
Conventionally, it was thought that detecting the movement speed of the track (line speed) could be reflected on the total of tracks already jumped, however, since detection of the line speed itself takes a certain amount of time, it was rarely used as an actual method of correction.
On the other hand, for example, in the case of a high-density optical disk, such as a DVD which is currently used as a reproduction-only disk, the lead-out area and lead-in area are rather large, so even when the position reached by the optical spot is a little off, the optical spot does not jump all the way to the unrecorded area, so position control of the optical spot is not lost.
However, in the case of a DVD-RW (DVD-Re-Recordable, a DVD which can be written over several times), which is recently becoming standard, before executing the ending process (finalization process), a temporary lead-our area and lead-in area are formed and recorded. Since these areas are very narrow, in the case of a DVD-RW disk, there is the problem that the danger of losing position control due to the optical spot jumping to the aforementioned unrecorded area increases.
In addition, the aforementioned track jump control method is executed the same for each optical disk, so when designing a player for a DVD-RW disk, there exists a problem of decreased design freedom.
SUMMARY OF THE INVENTION
In consideration of the above problems, it is the objective of the present invention to provide a track search control apparatus and track search control method that are suitable for all kinds of optical disks and that are capable of preventing the loss of position control as well as are capable of accurately finding the target track of the track jump, and reproducing or recording data; and to provide a data recording apparatus and data reproduction apparatus, which includes the track search control apparatus, and a data recording medium, on which a track search control program for controlling the track search operation is recorded and which is readable by a computer.
The above object of the present invention can be achieved by a track-search control apparatus that controls the search for a target track on a recording medium having tracks on which data are recorded. The apparatus is provided with: a judgment device for determining whether said recoding medium is a specific type of recording medium having a recorded area including said tracks on which data are already recorded, and an adjacent non-recorded area including said tracks on which data have not yet been recorded; a calculation device for calculating the number of said tracks on said recording medium from the currently detected track position to the position of said target track; a correction device for calculating the number of correction tracks for correcting the number of said tracks when said recording medium is said specific type of recording medium according to the result of said determining; and an execution device for executing the search of said target track based on the number of calculated said correction tracks.
According to the present invention, when the recording medium is a specific type of medium that contains both an unrecorded area and a recorded area, the target track is searched for using a corrected number of tracks that was corrected from the number of tracks corresponding to the target track, so it is possible to prevent the loss of position control due to trouble in servo control caused when the search position reaches inside the unrecorded area, and at the same time, it is possible to execute track search control that corresponds to the type of recording medium.
In one aspect of the present invention, said judgment device comprises a wobble d
Ladas & Parry
Neyzari Ali
Pioneer Corporation
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