JPS58212660A - Reproducing device of high density recording disc - Google Patents

Abstract

PURPOSE:To carry an information reader close to an objective position quickly and precisely at the time of retrieval, by compensating an output of a position detector by an error stroed in a storing part to retrieve the information of an optical of a high density recording disc. CONSTITUTION:Before random accessing, the absolute position information of a time code is previously read out at an optional position of a disc 1, an error between the read information and an output (b) from a converter is calculated by an operation controlling part 8 and the obtained error signal is stored in a storing part 9. If the increasing ratio of the absolute position information is equal to that of the output (b) of the converter, said error is uniform in the whole range of the disc. If the error is previously stored in the storing part 9 and the output (b) of the converter is compensated by the error signal stored in the storing part 9 when a pickup 3 is carried close to the objective position by the output (b) of the converter at the time of random accessing, the pickup 3 can be carried close to the objective position more precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-density recording disk reproducing device, and particularly to its random access.

When attempting to play back a desired position on a high-density recording disk (hereinafter referred to as a disk), an information reading device (hereinafter referred to as a pickup) retrieves the search position information recorded on the disk.
If you do this while reading, it will take time for the pickup to reach the target position.

In order to reduce the time required for this access, conventional methods include a position detection device that detects the position of the pickup relative to the disk, and the output of the position detection device is converted into a signal in the same format as the search position information recorded on the disk. The output of this converter allows the pickup to be moved to the vicinity of the target position without reading the search position information recorded on the disk, and then the pickup is moved to the target position while reading the search position information from the disk. The pickup was being moved to.

However, with this conventional method, when moving the pink amplifier to the vicinity of the target position using the converter output due to an error with the position information for converter output table search, it is not possible to move the pink amplifier sufficiently close to the target position, and the error occurs. Since the pickup must be moved for several minutes while reading the search location information, sufficient time reduction cannot be expected.

Furthermore, in order to reduce the error between the converter output and the search position information, the initial setting of the position detecting device must be performed with high precision, which makes the initial setting device expensive.

The present invention provides a high-density recording disk reproducing apparatus that improves these unreasonableness.

To prevent this, the present invention provides an arithmetic section for calculating the error between the search position information and the converter output, and a storage section for storing the output of this arithmetic section. Calculate the error and store it in the storage unit. At the time of random access, when the pickup is moved to the vicinity of the target position using the converter output, the converter output can be corrected with the error signal stored in the storage unit to search. Regardless of the error between the position information and the output of the converter, the pickup is brought sufficiently close to the target position.

Next, an optical digital audio player will be described as an embodiment of the present invention.

Time codes as shown in Table 1 are recorded on optical digital audio discs as search position information.

Table 1: In other words, it spans all the locations on the disc where music information is recorded, and shows which track, minute, and second the location is, and also indicates the starting location of the music information. Relative position information consisting of a lead-in signal and a lead-out signal indicating the end of the music information, and the relative position information that changes continuously across all locations on the disc where music information is recorded, and that location indicates the end of the music information. There are three types of information: absolute position information indicating how many minutes and seconds from the initial position of the screen, and index information indicating how many minutes and seconds the starting position of each side is in absolute position information. recorded as a time code.

When performing random access to such a disc, the target position in minutes and seconds of the music information is converted into absolute position information in minutes and seconds from the first position of the music information using index information, and that information is Hire a pick-up and move based on it.

FIG. 1 shows a block diagram of an embodiment of the present invention. In the figure, 1 is an optical digital audio disc, 2 is a disc rotation device, 3 is an optical pickup, 4 is a signal processing unit that extracts a time code from the pickup output, and 5
1 is a pickup driving device for driving the optical pickup 3 in the radial direction of the disk 1, 6 is a position detection device for the pickup 3, γ is a converter, 8 is a calculation and control section, and 9 is a storage section.

a is a pickup drive signal, b is a converter output, and C is a time code.

In this device, the converter output is in the same format as the absolute position information of time code C. That is, the converter 7 functions to convert the output of the pickup position detection device 6 into a signal having the same format as the absolute position information of the time code.

Since the converter output signal is generated even when the pickup 3 is not reproducing disc information, a heavy pickup drive signal a is supplied to the pickup drive device 6 from the calculation and control unit 8 based on this signal, and the pickup 3 is Move it to the desired position.

At this time, if there is an error between the converter output and the absolute position information, even if you try to bring the heavy pickup 3 near the target position closer to the converter output, it will move closer to the position farther away from the target position by that error. Put it away.

Of course, after bringing the pickup 3 closer to the target position using the converter output, it is possible to move the beam of the pickup 3 closer to the target position by performing track jumps etc. while playing back the time code of disc 1. The work of moving the pickup 3 closer together by track jumping, etc. has the disadvantage of being slower than the work of moving pickup 3 using the converter output, since the time code of disk 1 must be reproduced. If access is to be performed, it is advantageous to move the pickup 3 as close as possible to the target position using the transducer output, and to minimize the area in which the beam approaches the target position by track jumping or the like.

When attempting to move the big amplifier 3 as close as possible to the target position using the converter output, the error between the converter output and the absolute position information described above affects its accuracy.

FIG. 2 is a diagrammatic representation of the error between the converter output and the absolute position information.

In an optical digital audio disc, music information is recorded from the inner circumference to the outer circumference of the disk. The starting point of the music information recording portion is determined at the 25H position. Therefore, the absolute position information assumes that the position is 00 minutes and Oo seconds, and increases with the playing time as it moves toward the outer circumference in the radial direction.

The converter output is pickup 3 at radius 25 of disk 1.
It is mechanically detected that it is at the R position, and is reset to OO by OO, and increases from that position toward the outer circumference in the radial direction.

Since the converter output is mechanically reset 7), it is difficult to match the reset position with the starting point of the absolute position information of the disk. This is because optical digital audio discs have a narrow track pitch of 1.6 μm.
This is because a highly accurate reset switch is required.

Furthermore, if the eccentricity of the disk is taken into account, it becomes even more difficult to match the reset of the converter 7 with the starting point of the absolute position information.

Therefore, in this embodiment, before performing random access, the absolute position information of the time code is read in advance at an arbitrary position on the disk 1, and the error when outputting from the converter at that position is calculated and divided by the control unit 8. , the obtained error signal is stored in the storage unit 9
VC - Store - When the converter outputs, if the rate of increase in absolute position information is the same, this error will be the same in the entire area of the disk.Therefore, once this error is determined and stored in the storage unit 9,
Thereafter, during random access, when the pickup 3 is sent to the vicinity of the target position by the converter output, if the converter output is corrected using the error signal stored in the storage unit 9, the pickup 3 can be moved to the vicinity of the target position more accurately. I can send it.

Although the present invention has been described above using an optical digital audio player as an example, the present invention can be applied to other similar high-density recording disc playback devices.As described above, the present invention can be applied to an information reading device. An error between the output of the position detection device that detects the position and the search position information recorded on the high-density recording disk is stored in a storage section, and the output of the position detection device is compensated by the error stored in the storage section. (1) Since information is searched for at any arbitrary position on the high-density recording disk, the information reading device can be quickly and accurately sent to the vicinity of the target position during the search.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of its operation. 1... Disc (high density' recording disk), 2...
... Disc rotation device, 3 ... Pickup (information reading device), 4 ... Signal processing unit,
5...Pickup drive device, 6...
Position detection device, 7...Converter, 8...
Calculation, control section, 9... storage section.

Claims (1)

[Claims] A position detection device detects the position of the information reading device with respect to the high-density recording disk and converts it into an electrical signal. a converter that converts the signal into an electrical signal;
A calculation unit that calculates an error between the search position information and the converter output, and a storage unit that stores the output of the calculation unit, and the output of the converter is converted into an error signal stored in the storage unit. A high-density recording disk reproducing apparatus, characterized in that information at an arbitrary position on the high-density recording disk is retrieved by correcting the information.