JPS63168877A - Optical disk device - Google Patents

Abstract

PURPOSE:To perform a random access based on an actual linear speed of an optical disk by counting the pulses received from an encoder just for a fixed period of time and calculating the disk linear speed based on the number of said counted pulses. CONSTITUTION:A rotary encoder 14 is attached to the shaft of a spindle motor 1 and a counter 15 which counts the pulses received from the encoder 14 just for a second is provided. This counter 15 is connected to a system control circuit 7 which contains a program, i.e., a linear speed arithmetic means which calculates the linear speed of an optical disk from the data on the number of pulses counted by a counter 15 for a second. Thus this calculated linear speed of the disk is stored as a basic linear speed for a random access. In such a way, an accurate random access is attained at a high speed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a disk device, and specifically relates to a disk Q system for realizing high-speed and accurate random access.
This is related to change detection.

[Conventional Technique] Currently, compact discs (so-called CDs), compact discs, and read-out memories using compact discs (so-called CD-ROMs) operate at a constant linear velocity (so-called C L V) recording method is adopted. According to the standard, the linear velocity is 1.
It is said that a constant speed within the range of 2 to 1.4 Th (meter/th) is sufficient.

By the way, a CD or CD-ROM is subcoded with a certain notation tJ'<subtrack address, for example, the absolute time (minutes, minutes, number of frames) T from the starting point of the inner circumference of the disc. . Note that one frame in the absolute time T is a value obtained by dividing one sand into 1/75th. Therefore, once the linear velocity of the disk is determined, the absolute time T and the position of the track; °d (for example, the number of tracks from the starting point The relationship between

This absolute time T and the track r from the beginning of the disc
! ! , (position)
i? O: For vI devices, the four springs are generally 1 and 2.
Calculate the relationship as m/s (meter 7 seconds),
The relationship is stored in a table inside the CD device6. Then, at the time of random access, the table is indexed to find the current track position FL (number of tracks from the starting point) and the target track position (number of tracks from the starting point). The number of tracks to be moved, that is, the distance to be moved, was determined based on the difference between the two, and the motor for driving the pickup feed was controlled.

As mentioned above, a conventional CD device or CD-RO
M! In this case, without determining the linear velocity of the individual disks, the linear velocity of the individual disks is determined by #;I!, which is typically 1.2 m/s. Random access was performed at specified times.

[Problems to be Solved by the Invention] If random access is performed at a uniform linear speed of 1.2+o/s for all disks as in the conventional CD device described above, the linear speed of the disk will be just In the case of 1.2 m/s, the specified linear velocity of the CD device 1'lF matches the actual linear velocity of the disc, so high-speed and accurate access is possible.
In the case of a disk other than s, the calculated number of track jumps has a considerable error with respect to the actual number of tracks to be skipped, and this causes a problem that the access time becomes long.

An object of the present invention is to solve the above-mentioned deficiencies of the conventional technology and to obtain a flexible disk device that enables high-speed and accurate random access.

[Means for solving the problem 1] In this invention, in order to solve the above-mentioned interval M7α, an encoder that emits a pulse every time the shaft of the spindle motor rotates by a certain angle, and a pulse from this encoder (C) are transmitted for a certain period of time. The present invention is configured to include a counter that counts the number of pulses counted by the counter, and linear velocity calculation means that calculates the linear velocity of the disk based on the number of pulses counted by the counter.

[Effect 1: Since the actual linear velocity of the CD or CD-ROM to be used is determined, the actual linear velocity of the CD or CD-ROM to be used is determined by the number of tracks to be moved during random access. It can be used as the basis for one output (distance). Therefore, the calculated number of track jumps (
The distance to be moved) is accurate, and high-speed and accurate random access is possible regardless of differences in the linear speed of individual disks.

[Example 1 Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The figure is a block diagram of CDvcfl according to one embodiment of the present invention.
is a spindle motor, 2 is a disk, 3 is a pickup, 4 is a reproduction signal amplifier, 5 is a digital signal processing circuit, 6
7 is a servo signal processing circuit, and 7 is a system control circuit.

8 is an audio conversion processing circuit, a digital filter 9,
It is equipped with a differential/analog converter 10, an audio circuit 11, and the like.

Note that in the case of a CD-ROM device, instead of the audio conversion processing circuit 8, a CD-ROM device shown by a two-dot chain line is used.
M circuit 12 is connected. In addition, 13 is an address table, and this address table 13 has a linear velocity of 1.2 m.
The number T of tracks from the starting point of the disk, calculated as /s (this is 9 information representing the position of the track), is stored.

The system configuration in the range described above is almost common to a conventional CD device or CI-ROM device.

In the embodiment of the present invention, a rotary encoder 14 is attached to the shaft of the spindle motor 1, a counter 15 for counting pulses from the rotary encoder 14 for one second is provided, and this counter 15 is connected to the system control circuit 7. The system control circuit 7 incorporates a program that calculates the linear velocity of the disk from the pulse number data counted by the counter 15 for one second, that is, linear velocity calculation means.

Then, the disk linear velocity V detected by the above calculation is
It is stored as the linear velocity that is the basis for random access.

In the above configuration, when the CD device is started, the spindle motor 1 first rotates, and after performing various initializations, the pickup 3 moves to the lead-in area on the inner circumference of the disc, and the TOC (Table of Functions) there is moved. ). During this lead-in, the counter 151 counts pulses emitted from the rotary encoder 14 attached to the shaft of the spindle motor 1 for only one second.
This counted pulse number data is sent to the system control circuit 7.
Send to. The system control circuit 7 calculates the linear velocity \l of the disk based on this pulse number data. This calculation formula calculates the disc diameter at the lead-in time of the disc by D(
P1 counter 15 measures the number of pulses generated by the rotary encoder 14 during one rotation of the spindle motor 1.
If the number of pulses counted for 1 second is N, then the following formula, \I = πD N / P ・・・・・・・・・■
The upward linear velocity Vm/s is calculated.

Then, the system control circuit 7 performs random access based on this linear velocity ■. Since this linear velocity V is the actual #iI speed of the disk, the number of tracks to be skipped is calculated based on this m speed. is accurate. Therefore, high speed and accurate random access is realized.

S, in the above random access, the absolute time ′I
When indexing Table 13 of the relationship between '' and the number of trunks ,? The tiger that was directly indexed in between? Instead of using the number of tracks X as is, the number of tracks X′ obtained by multiplying the number of tracks X by a correction coefficient is used. The value of this correction coefficient is (detected linear velocity/designated linear velocity), which is V/1.2 in the example. This corrected exact beginning, 1,
By using the number of tracks (position) x from χ, it is possible to accurately calculate the number of tracks to be skipped.5 The actual disk linear velocity calculated as above is:
It can also be used to control the rotation speed of the spindle motor 1.

Note that the time counted by the counter 15 is the same as that in Example 1.
It is not limited to seconds, and if it is not 1 second IIn, the above equation 0 may be multiplied by a coefficient corresponding to the value of the fixed time.

Further, the present invention is not limited to current CD devices and CD-ROM devices, but similarly, the present invention can be used to attach an address table storing track addresses such as absolute time 1713 calculated at a specified IQ speed to a disk device. It is possible to apply it.

[Effects of the Invention] As explained above, according to the present invention, there is provided an encoder that transmits a pulse every time the shaft of a spindle motor rotates by a certain angle, a counter that counts pulses from the encoder for a certain period of time, and Since the speed calculating means #a which calculates the speed m of the disk based on the number of pulses counted by the speed calculation means is configured in a similar manner, it is possible to perform random access based on the actual speed m of the disk. It has become possible to perform high-speed and accurate random access regardless of differences in #am speed of individual disks.

[Brief explanation of the drawing]

The figure is a block diagram of a CD I device showing one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Spindle motor, 7...System control circuit, ]3...Address table, 14...Low reencoder, 15...Counter.

Claims (1)

[Claims] In an optical disk device that has an address table that stores track addresses calculated at a specified linear velocity, there is an encoder that emits a pulse every time the spindle motor shaft rotates by a certain angle, and a counter that counts the pulses from this encoder for a certain period of time. and linear velocity calculation means for calculating the linear velocity of the disc based on the number of pulses counted by the counter.