JPH05234100A - Recording information reproducing device - Google Patents

Abstract

PURPOSE:To provide the recording information reproducing device whose cost is low and whose retrieval accuracy is high, that is, whose retrieval time is short without much increasing the memory capacity, in the recording information reproducing device such as a compact disk player, etc. CONSTITUTION:The device is provided with an intermediate peripheral position storage means for setting and storing in advance a distance extending from the center of a disk 1 to the intermediate peripheral position of the disk at the time of retrieving information by a control microcomputer 9 and a memory 10 annexed thereto. In such a way, when for instance, the Newton-Raphson method is used for extracting a square root, a starting value of an iteration formula can be set to the intermediate peripheral position of the disk, and a moving amount can be calculated comparatively easily, and also, with stable accuracy extending from the inside peripheral to the outside periphery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recorded information reproducing apparatus such as a compact disc player.

[0002]

2. Description of the Related Art Conventionally, in the information retrieval in a recording information reproducing apparatus of this kind with a constant linear velocity, in order to find the difference between the target position and the current position, a complicated calculation including the square root square root is originally required. For this reason, normally, a comparison storage means is provided which stores the time information in the disc and the distance from the center of the disc in association with each other in advance. Generally, the comparison storage means is provided as a table in the memory of the control microcomputer that controls the mechanism of the stored information reproducing apparatus. At the time of information retrieval, the corresponding distance was obtained from the table based on the time information.

[0003]

However, in the conventional method, the table area must be secured in the memory, and the memory capacity inevitably increases. In order to further improve the accuracy, it is necessary to increase the number of data in the table and further increase the memory capacity. Moreover, since a table is used, there is a limit in accuracy. An increase in the memory capacity leads to an increase in the cost of the control microcomputer system and also an increase in the cost of the entire apparatus. Moreover, if the accuracy is low, the information retrieval time is deteriorated.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a recorded information reproducing apparatus which has a low cost and a good search accuracy, that is, a short search time without greatly increasing the memory capacity.

[0005]

In order to achieve the above object, the present invention provides a current time information reading means for reading time information arranged on a disc at the time of information retrieval, and a distance from the center of the disc to a middle circumferential position of the disc. Is set and stored in advance, and the distance from the center of the disc to the position where the optical pickup is present (currently) by using the distance of the intermediate position and the current time information read by the current time information reading unit. A current position calculation means for obtaining a position), a target position storage means for storing time information (target time) to be searched for given from the outside, and a disk using the stored distance between the target time and the middle circumferential position. Target position calculating means for obtaining a distance (target position) from the center to a position on the disk where the target time is, and a distance difference between the current position and the target position. A distance difference calculation means for obtaining, in which a structure having an access means for moving the optical pickup by a distance corresponding to the distance difference by a stepping motor.

Further, means for reading time information arranged on the disc at the time of information retrieval, and the inner circumference to the outer circumference of the disc are divided into appropriate areas, and the center position in each area and the distance from the center of the disc are divided. Area storage means for setting and storing each area in advance, current area selecting means for selecting the area from each area using the current time read by the means for reading the time information, the current time and the area Current position calculating means for obtaining the distance (current position) from the center of the disc to the position where the optical pickup currently exists, and the target time for storing time information to be searched (target time) given from the outside. Storage means, target area selection means for selecting the area from each area using the stored target time, and the target time Target position calculating means for obtaining a distance (target position) from the center of the disc to a position on the disc having a target time using the center position of the area, and a distance difference for obtaining a distance difference between the current position and the target position. The calculation means and the access means for moving the optical pickup by a stepping motor by a distance corresponding to the distance difference are provided.

Further, at the time of information search, there are a lens shift detecting means for detecting a shift from the center of the objective lens and the optical pickup just before the start of the information search, a lens shift storing means for storing the lens shift amount, and a current optical pickup. Distance difference calculating means for obtaining the distance difference between the position and the position on the disc having the time information to be searched for which is externally provided, and the obtained distance difference from the stored objective lens and the center of the optical pickup. The configuration includes a correction unit that corrects according to the amount, and an access unit that moves the optical pickup by a stepping motor by a distance corresponding to the corrected distance difference.

[0008]

With this configuration, it becomes possible to calculate the position, and by providing the intermediate position storing means for presetting and storing the distance from the center of the disk to the intermediate position of the disk, for example, the Newton-Raphson method can be used for square root square rooting. When used, the starting value of the iterative formula can be set at the center position of the disk, and the movement amount can be calculated relatively easily and with stable accuracy from the inner circumference to the outer circumference. Therefore, the table in the memory can be eliminated.

Further, by providing area storage means for dividing the inner circumference to the outer circumference of the disk into appropriate areas and setting and storing the center position in each area and the distance from the center of the disk in advance for each area. , It is possible to change the starting value of the iterative formula according to the target position and a simple table is required, but the accuracy is improved even if the number of iterations is reduced, so that the calculation time can be shortened.

Further, at the time of information search, by providing a lens shift detecting means for detecting a shift from the objective lens and the center of the optical pickup immediately before the start of the information search and a lens shift storing means for storing the lens shift amount, the information search starts. It is possible to detect and store the deviation of the objective lens from the center of the optical pickup immediately before, and increase or decrease the deviation amount from the calculation result at the time of position calculation. Since the positional error with the lens can be corrected, the movement accuracy is improved and the search time can be shortened.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a disk having a spiral information track, 2 is a spindle motor for rotating the disk 1, 3 is an optical pickup, 4 is an objective lens in the optical pickup 3, 5 is a focus servo circuit, and 6 Is a tracking servo circuit, 7 is a stepping motor that moves the optical pickup 3, 8 is a stepping motor drive circuit that drives the stepping motor 7, 9 is a control microcomputer that controls the servo system by external commands and executes various calculations, Reference numeral 10 is a memory of the control microcomputer 9.

The control microcomputer 9 and the accompanying memory 10 preset the current time information reading means for reading the time information arranged on the disk 1 at the time of information retrieval and the distance from the center of the disk 1 to the disk middle position. The distance from the center of the disk 1 to the position where the optical pickup 3 is present (current position) using the intermediate position storage means for storing, the distance of the intermediate position and the current time information read by the current time information reading means. ), A current position calculation means for calculating the present position, a target position storage means for storing time information (target time) to be searched for given from the outside, and a disk 1 using the distance between the stored target time and the middle circumferential position. Position calculating means for obtaining the distance (target position) from the center of the position to the position on the disk 1 with the target time, the current position and the target position A distance difference calculation means for obtaining a distance difference between, and has a means for delivering a step pulse to the stepping motor drive circuit 8.

The operation will be described below. When the target time and the information retrieval command are given to the control microcomputer 9 from the outside,
The control microcomputer 9 reads the time information arranged on the disk 1 as the current time via the optical pickup 3 and stores it in the memory 10. Next, the control microcomputer 9 converts the present time into a distance from the center of the disc 1. At this time, since it is necessary to open the square root, Newton-Pap
Calculate using the hson method. As the initial value of the iterative formula, the value of the middle position of the disk 1 previously stored in the memory 10 is used. It is around 41 on CD. Iterate the formula two or three times to find the distance. Similarly, the control microcomputer 9 then finds the distance from the center of the disk 1 at the target time. Next, the control microcomputer 9 finds the difference between the target and the distance from the center of the disk 1 at the current time, converts the difference into a step number, and sends a step pulse corresponding to the step number to the stepping motor drive circuit 8 for stepping. The motor drive circuit 8 drives the stepping motor 7 to move the optical pickup 3 to the target position.

A second embodiment of the present invention will be described. In the second embodiment, the control microcomputer 9 and the memory 10 shown in FIG.
Means for reading time information arranged on the disc 1 at the time of information retrieval, and dividing the inner circumference to the outer circumference of the disc into appropriate areas, and dividing the center position in each area from the center of the disc 1 Area storage means for setting and storing each area in advance, current area selecting means for selecting the area from each area using the current time read by the means for reading the time information, the current time and the area Using the center position of the disk 1
A current position calculating means for obtaining a distance (current position) from the center of the optical pickup 3 to the position where the optical pickup 3 is present, and a target time storing means for storing time information (target time) to be searched given from outside. Target area selecting means for selecting the area from each area using the stored target time, and the disk 1 having a target time from the center of the disk 1 using the target time and the center position of the area Target position calculation means for obtaining a distance to the upper position (target position), distance difference calculation means for obtaining a distance difference between the current position and the target position, and means for sending a step pulse to the stepping motor drive circuit 8 are provided. Have

The operation will be described below. When the target time and the information retrieval command are given to the control microcomputer 9 from the outside,
The control microcomputer 9 reads the time information arranged on the disk 1 as the current time via the optical pickup 3 and stores it in the memory 10. Next, the control microcomputer 9 converts the present time into a distance from the center of the disc 1. At this time, since it is necessary to perform square root square root, Newton-Ra
Calculate using the phson method. When the optical pickup 3 is on one area of the divided area of the disc 1,
The control microcomputer 9 selects a center position of the area preset in the memory 10 from the memory 10, and calculates the center position of the area as an initial value of an iterative formula in the Newton-Raphson method. The number of repetitions may be less than in the first invention. When the number of iterations is the same as that of the first invention, the calculation accuracy is higher than that of the first invention. Similarly, the control microcomputer 9 then finds the distance from the center of the disk 1 at the target time. Next, the control microcomputer 9 obtains the difference between the target and the distance from the center of the disk 1 at the current time and converts the difference into the number of steps,
Step pulses corresponding to the number of steps are sent to the stepping motor drive circuit 8, and the stepping motor drive circuit 8 drives the stepping motor 7 to move the optical pickup 3 to the target position.

A third embodiment of the present invention will be described.
2, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 2, reference numeral 11 denotes a lens shift detecting means for detecting a shift from the center of the objective lens 4 and the optical pickup 3 just before the information search is started at the time of information search. The lens shift amount is controlled by the control microcomputer 9 and the memory 10. And a distance difference calculation means for calculating a distance difference between a position where the optical pickup 3 is present and a position on the disk 1 where there is time information to be searched externally given, and Correction means for correcting the obtained distance difference according to the stored deviation amounts of the objective lens 4 and the optical pickup 3 from each other, and a stepping motor drive circuit by the number of steps corresponding to the corrected distance difference. 8 has means for sending a step pulse.

The operation will be described below. When the target time and the information retrieval command are given to the control microcomputer 9 from the outside,
The control microcomputer 9 reads the time information arranged on the disk 1 as the current time via the optical pickup 3 and stores it in the memory 10. At the same time, the lens shift detecting means 11 detects the shift from the center of the objective lens 4 and the optical pickup 3 and stores the shift amount in the memory 10. Next, the control microcomputer 9 calculates the distance difference between the position where the optical pickup 3 is present and the position on the disk 1 where the time information to be searched for, which is externally given, is found. It is carried out in the same manner as the second embodiment of the invention. Next, the control microcomputer 9 increases or decreases the obtained distance difference according to the deviation amount and corrects the distance difference. Next, the control microcomputer 9 converts the corrected distance difference into the number of steps,
Step pulses corresponding to the number of steps are sent to the stepping motor drive circuit 8, and the stepping motor drive circuit 8 drives the stepping motor 7 to move the optical pickup 3 to the target position.

[0019]

As is apparent from the above description, according to the present invention, it is possible to calculate the position, and by providing the intermediate position storage means for presetting and storing the distance from the center of the disk to the intermediate position of the disk, For square root Kaihei, for example, Ne
When the wton-Raphson method is used, the starting value of the iterative formula can be set to the middle position of the disk, and the movement amount can be calculated relatively easily and with stable accuracy from the inner circumference to the outer circumference. Becomes Therefore, the table in the memory can be eliminated, and it is possible to provide a recording information reproducing apparatus which has a low cost and a high search accuracy, that is, a short search time without greatly increasing the memory capacity.

In the second embodiment of the present invention, the inner circumference to the outer circumference of the disk are divided into appropriate areas, and the center position in each area and the distance from the center of the disk are set in advance for each area. By providing the area storage means for storing, it becomes possible to change the starting value of the iterative formula in accordance with the target position, and a simple table is required, but the accuracy improves even if the number of iterations is reduced, so the accuracy is improved. It is possible to provide a recorded information reproducing apparatus in which the calculation time can be shortened without any loss and the search time can be further shortened.

In the third embodiment of the present invention, a lens shift detecting means for detecting a shift between the objective lens and the center of the optical pickup immediately before the information search is started at the time of information search, and a lens shift storage for storing the lens shift amount. By providing the means, it is possible to detect and store the deviation of the objective lens from the center of the optical pickup immediately before the start of information search, and increase or decrease the deviation amount from the calculation result at the time of position calculation. Since it is possible to correct the amount of movement and the position error between the objective lens and the objective lens where information is actually read, it is possible to further improve the movement accuracy and provide a recorded information reproducing apparatus with a short search time.

[Brief description of drawings]

FIG. 1 is a block diagram of a recorded information reproducing apparatus according to a first embodiment and a second embodiment of the present invention.

FIG. 2 is a block diagram of a recorded information reproducing apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

 1 disk 2 spindle motor 3 optical pickup 4 objective lens 5 focus servo circuit 6 tracking servo circuit 7 stepping motor 8 stepping motor drive circuit 9 control microcomputer 10 memory 11 lens deviation detection means

Claims (3)

[Claims] 1. A disk having spirally recorded information, a spindle servo means for rotating the disk at a constant linear velocity, an optical pickup for reading the information recorded on the disk, and an objective in the optical pickup. A tracking servo means for controlling the lens so as to follow the information track of the disc, a focus servo means for controlling focus adjustment when reading information recorded on the disc by the optical pickup, and a tracking direction for the optical pickup. Traverse servo means having a stepping motor for moving to, current time information reading means for reading time information arranged on the disc at the time of information retrieval, and presetting and storing a distance from the center of the disc to the disc middle circumferential position. The peripheral position storage means and the intermediate position Current position calculation means for obtaining the distance (current position) from the center of the disk to the position where the current optical pickup is present using the distance and the current time information read by the current time information reading means, and a search provided from the outside should be performed. A target position storage means for storing time information (target time), and a distance (target position) from the center of the disk to a position on the disk where the target time is, using the stored distance between the target time and the intermediate position. Recording information reproducing apparatus having target position calculating means for obtaining, distance difference calculating means for obtaining distance difference between the current position and the target position, and access means for moving the optical pickup by a stepping motor by a distance corresponding to the distance difference. .. 2. A disk on which information is spirally recorded, spindle servo means for rotating the disk at a constant linear velocity, an optical pickup for reading the information recorded on the disk, and an objective in the optical pickup. A tracking servo means for controlling the lens so as to follow the information track of the disc, a focus servo means for controlling focus adjustment when reading information recorded on the disc by the optical pickup, and a tracking direction for the optical pickup. Traverse servo means having a stepping motor to move to, a means for reading the time information arranged on the disk at the time of information retrieval, and the center position in each area by dividing the disk from the inner circumference to the outer circumference into appropriate areas Set the distance from the center of the disc for each area in advance Area storage means for storing, current area selecting means for selecting the area from each area using the current time read by the time information reading means, and disk using the current time and the center position of the area Current position calculation means for obtaining a distance (current position) from the center to a position where the optical pickup is currently present, and target time storage means for storing time information (target time) to be searched, which is given from the outside, and is stored. Target area selecting means for selecting the area from each area using the target time, and the distance from the disk center to the position on the disk having the target time using the target time and the center position of the area (target Position), a distance difference calculating means for calculating a distance difference between the current position and the target position, and the distance. Recorded information reproducing apparatus having an access means for moving the optical pickup by a distance corresponding to the difference by a stepping motor. 3. A disk on which information is recorded in a spiral shape, a spindle servo means for rotating the disk at a constant linear velocity, an optical pickup for reading the information recorded on the disk, and an objective in the optical pickup. A tracking servo means for controlling the lens so as to follow the information track of the disc, a focus servo means for controlling focus adjustment when reading information recorded on the disc by the optical pickup, and a tracking direction for the optical pickup. Traverse servo means having a stepping motor for moving the lens, lens shift detecting means for detecting a shift from the objective lens and the center of the optical pickup just before starting the information search, and lens shift storing means for storing the lens shift amount. , Currently there is an optical pickup Distance difference calculating means for calculating the distance difference between the position on the disc having the time information to be searched, which is externally given, and the calculated distance difference from the stored objective lens and optical pickup center. A recorded information reproducing apparatus having a correction means for correcting according to the amount of deviation and an access means for moving the optical pickup by a stepping motor by a distance corresponding to the corrected distance difference.