JPS6214333A - Optical information device - Google Patents

Abstract

PURPOSE:To prevent the generation of an address error by calculating the absolute position of a desired sector of a desired track of a recording medium and then the error between the absolute position of the track and the present position of an optical head and controlling a shift means based on said error. CONSTITUTION:A memory 43 stores addresses (a1-an) of all sectors S1-Sn of the most inner circumferential track (to) and the absolute position. On the most outer circumferential track (tm), both an optical head 26 and an encoder 41 have the same sequence as the track (to) to read the addresses a1-an of all sectors S1-Sn of the track (tm) and store them in the memory 43. Then the position liner coefficient eta of each sector is obtained based on the absolute positions and addresses of all sectors of both tracks (to) and (tm). A CPU 21 reads the present address where the head 26 exists and the absolute position by an address reproducing circuit 34 and the encoder 41 and then calculates an error against the desired address from the present address and the absolute position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an optical information device capable of optically recording or reproducing information.

In this specification, an apparatus having either or both of the functions of optically recording information on a medium and optically reproducing information from a medium on which information is recorded is referred to as an optical information device.

[Prior art]

2. Description of the Related Art Optical information devices have been known for their ability to handle high-density information. The optical information recording medium used in such an apparatus can have a track density that is two orders of magnitude higher than that of a magnetic recording medium. In other words, the track pitch is narrowed to about twice the aperture diameter of the laser beam, so it is 1.5
#L-~2.0 Can be set to the value of #Lpeng. In order to achieve such a narrow track pitch, optically detectable guide tracks are formed on the magneto-optical disk, and tracking servo is applied to the guide tracks to record or reproduce information. Depending on this guide track,
It is possible to construct an optical information device that can stably record and reproduce optical information even against disturbances such as eccentricity and shaking caused by replacing the optical information recording medium.

FIG. 1 shows an optical information recording medium, where the optical information recording medium IO has an optically detectable sector structure,
Sectors 5l-3n are the address parts a1 to a of the starting area.
n and data sections d1 to dn. Further, numeral 11 in the figure is a guide track.

FIG. 2 shows a conventional optical information device, and the head drive system in this device will be mainly explained.

In FIG. 2, the optical head 26 follows the guide track 11 of the optical information recording medium 10 by focus control and tracking control. This optical head 26 accesses a predetermined guide track 11 by means of a linear motor 27 . The central processing unit H (hereinafter referred to as CPU) 21 is
The current address where the optical head 26 is located (a++a2.
・・・・・・・・・・・・

an) is read by the address reproducing circuit 34, the difference from the target address is set in the linear motor driver 31, the linear motor 27 is moved, the 0 degree address is read, and [
Determine whether the address is 1 or 1. If there is a mismatch,
Seek the guide track for the target address by repeating this sequence.

By the way, as mentioned above, the pitch of the guide track 11 in the optical information recording medium is 1.5 #L1 to 2.0 #
Since it is narrowed to L■, there is a problem that the address deviation in the radial direction of the medium IO becomes large due to eccentric deviation due to thermal expansion or thermal contraction of the recording medium due to changes in the surrounding environment such as temperature changes. there were.

However, in the conventional device, no means for correcting address deviation in the radial direction due to environmental changes as described in 1-1 has not been taken. Therefore, optical head 2
6, the actual optical head 2 is accessed based on the set value for the target address by the CPU 21 and the set value.
There is a drawback that the difference from the address accessed by No. 6 becomes large.

[Purpose of the invention]

The present invention has been made to eliminate the above-mentioned drawbacks, and aims to provide an optical information device in which address errors do not occur due to changes in the surrounding environment such as temperature changes.

〔Example〕

The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 3 shows an embodiment of the present invention. Here, the characteristic part of the embodiment of the present invention is that a linear motor 27 as a moving means is attached with an encoder 41 as a detection means, a memory 43 is provided, and The CPU 2 performs the absolute position calculation operation of all sectors and the control of the moving means, which will be described later.
1. Note that the other parts are the same as those of the conventional example, so the explanation thereof will be omitted.

FIG. 4 shows the relationship between the optical head 26 and the optical information recording medium 10, in which 51 is an objective lens, 26 is an optical head, 27 is a linear motor, 54 is a drive unit, 55 and 56 are bearings, and 57 59 is a guide shaft, and 59 is a medium shaft.

FIG. 5 is a diagram showing the encoder 41 shown in FIG. 3, in which 61 is a carriage, 62 is an encoder plate, and 63
is a photo interrupter.

This encoder 41 is configured to read information 64 on an encoder plate 62 using a photointerlab 3.

-L The operation of the above configuration will be explained below with reference to the flowchart of FIG.

First, when the optical information recording medium IO is installed in this optical information device, the spindle motor 28 rotates, and the operation of the linear motor 27 causes the optical head 26 to move to the innermost track of the guide track 11 of the medium 10. to
is accessed (step 81).

When the optical head 26 accesses the innermost track to, the optical head 26 reads each sector address of the innermost track to, and at the same time reads the absolute position of the optical head 26 using the encoder 41 shown in FIG. . Here, reading is performed by moving the optical head 26 with a linear motor 27 while the actuator remains identified, and the optical head 26 for each sector address in the track to is read.
The absolute position is read (step 82), where the absolute position is the distance between the medium position and the sector with respect to a certain position M (for example, the center axis of the medium) of the medium-E. The address and absolute position of each sector read by the optical head 26 and encoder 41 are stored in the memory 43.

In this way, all sectors 31 to S of the innermost track to
The address (al-an) and absolute position of n are stored in memory 4.
3 (step 82-1), the optical head 26
is accessed to the outermost track t■.

Even when the outermost track is layered, the optical head 26 and encoder 41 are operated in the same sequence as the innermost track.
Addresses a1-a of all sectors S1 to Sn of track t■
n and the absolute position are read (step 83) and stored in the memory 43 (step 83-1).

Based on the addresses and absolute positions of all sectors of the innermost track to and the outermost track obtained by the operation described above, calculate the (Q position linear coefficient η) of each sector.Here, the position linear coefficient η is defined as follows: The innermost track to and the outermost track are defined as the pth sector (l
If the absolute positions of ≦intersection≦n) are respectively Xo, sentence, and Xs, sentence, then the position linear coefficient of one sentence is: ...It is given as (1). Here, m is a numerical value in the guide track 11 to which the outermost track tm belongs.

It is necessary to find the WFli line coefficients η1 to ηn for all sectors S1 to Sn. To do this, first set the parameter l=1, read the data obtained in steps 82 and 83 above from the memory 43, obtain the coefficient η1 based on the above equation (1) (step 84), and then store the data at a predetermined location in the memory 43. Accumulate (step 84-1) 0 Next, it is determined whether this parameter 9 has become n (: number of sectors) (step 85). If the determination is negative, the parameter party is incremented (step 86), Return to step 84. If an affirmative determination is made in step 85, it means that the position linear coefficients η1 to ηn have been determined for all sectors, and the cumulative value Σ+η of the coefficients η1 to ηn is stored in the memory 43.

Next, the average value of the position linear coefficients η1 to ηn is −Ση η=□ ・・・・・・・・・・・・・・・・・・
...Determine by (2) and store in the memory 43 (
Step 87), this sequence is performed by the CPU 21. At this stage, the CPU 21 has completed the initial settings for seeking the target sector address.

Next, the operation of seeking a target sector will be explained.

First, the CPU 21 transmits the current address and absolute position of the optical head 26 to the address reproduction circuit 34 and the encoder 4.
1 (step 88).

Calculate the difference between the read current address and absolute position to the destination address. If p is the track address to which the target sector belongs, then the average absolute position 1xp of track p is: Xp=ηIp+XO...・・・・・・・・・(3)
(It is given as the position of xo nidrak to. The difference between this average absolute position 1xp and the current position lx of the optical head 26 is L=xp −x
This difference is obtained as (4) (step 89), and the linear motor 27
and moves the optical head 26 accordingly (step 90).

Thereby, correction for eccentricity due to temperature difference is performed.

In addition, when the optical head 26 seeks the target sector, if the target sector is an alternating sector in the track p to which the target sector belongs, the absolute position of the target sector, xp, 41, is xp, JJ = η sentence ・p
(5) The optical head 26 accessed the sector position xp, JJ of the alternating box ■ of the track p' where the optical head 26 is currently located a while ago, and from XP' + 1 to L
'=xp, xp', intersection (6) is obtained, and this L' is sent to the linear motor 27. A method of accessing the optical head 26 in this manner may also be used.

In addition, in the above description, the innermost track to and the outermost track of the guide track 11 in the optical information recording medium 10 are set as the two innermost tracks, but any two tracks may be used. A configuration may also be adopted in which correction data is obtained based on the - track.

With this configuration, by providing the means 41 for detecting the absolute position of the sector in the optical information recording medium, access errors of the optical head due to environmental changes such as temperature differences can be eliminated.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to realize an optical information device that is free from access errors due to changes in the surrounding environment such as temperature changes.

[Brief explanation of the drawing]

FIG. 1 is a planar structural diagram for explaining an optical information recording medium having a sector structure, FIG. 2 is a block diagram showing the configuration of a conventional optical information device, and FIG. 3 is an optical information recording medium according to an embodiment of the present invention. 4 is a block diagram showing the configuration of the optical information device, FIG. 4 is an exfoliation diagram showing the relationship between the optical head and the optical information recording medium, and FIG. 5 is a block diagram for explaining the configuration of the encoder of the linear motor shown in FIG. 3. The schematic diagram, FIG. 6, is a flowchart for explaining the operation of the embodiment of the present invention shown in FIG. 81-sn... Sector a1-an... Address section d1-dn... Data section lO... Information recording medium 11
・・・・・・・・・・・・・・・Guidance track to...
・・・・・・・・・・・・Peng the innermost track...
.........Outermost track 21...
・・・・・・・・・CPtJ as control means and absolute position calculation means

Claims (1)

[Claims] A recording medium comprising a plurality of tracks divided into a plurality of optically detectable sectors, an optical head for recording and reproducing information on the recording medium, and moving the optical head in a radial direction of the track. an optical information device having a moving means for detecting the absolute positions of a plurality of sectors on a predetermined track of the recording medium, and a detection means for detecting the absolute positions of a plurality of sectors on a predetermined track of the recording medium; absolute position calculating means for calculating the absolute position of a desired sector on the track; calculating means for calculating the difference between the absolute position of the track and the current position of the optical head; and controlling the moving means based on the calculated difference. An optical information device comprising a control means.