METHOD AND APPARATUS FOR DETECTING OPTICAL DISK TYPE
A method to determine the diameter and shape of the loaded optical disk without any additional sensor. By accelerating a disk for a certain period of time and then monitoring the rotational speed before the spindle lock, the diameter and shape of the loaded optical disk is detected.
1 . A method for detecting a disk size of an optical disk mounted on a spindle, comprising:
accelerating the optical disk on the spindle for a predetermined period of time;
detecting a speed of a disk by using a data clock signal produced by reading data on the disk after said accelerating;
comparing the disk speed with a predetermined speed; and
detecting the disk size by a result of the comparison.
2 . The method according to claim 1 , wherein the accelerating is effected at a predetermined force.
3 . The method according to claim 1 , wherein the detecting is carried out such that, if the disk speed is greater than the predetermined speed, the disk is detected as an 8 cm disk, and if the disk speed is less than the predetermined speed, the disk is detected as a 12 cm disk.
4 . The method according to claim 1 , further comprising issuing a servo ON command after the accelerating and before the detecting.
5 . The method according to claim 1 , wherein the detecting is effected by counting the frequency of data clock signal.
6 . The method according to claim 5 , wherein the counting is carried out by an external system microcomputer using a counting signal produced from a digital signal processor.
7 . The method according to claim 5 , wherein the counting is carried out by a servo signal processing unit, and the counting result is sent to an external system microcomputer.
8 . The method according to claim 1 , wherein the detecting detects disk diameter.
9 . The method according to claim 1 , wherein the detecting detects disk shape.
10 . The method according to claim 1 , wherein the detecting is carried out by comparing the disk speed with a regular disk playing speed.
11 . The method according to claim 1 , wherein the detecting is carried out by finding one of a plurality of ranges in which the disk speed falls in.
12 . An apparatus for detecting a disk size of an optical disk mounted on a spindle, comprising:
an accelerating device operable to accelerate the optical disk on the spindle for a predetermined period of time;
a first detecting device operable to detect a speed of a disk by using a data clock signal produced by reading data on the disk after accelerating;
a comparing device operable to compare the disk speed with a predetermined speed; and
a second detecting device operable to detect the disk size by a result of the comparison.
13 . The apparatus according to claim 12 , wherein the accelerating device has a computer by which accelerating is effected at a predetermined force.
14 . The apparatus according to claim 12 , wherein the second detecting device carries out the detection such that, if the disk speed is greater than the predetermined speed, the disk is detected as an 8 cm disk, and if the disk speed is less than the predetermined speed, the disk is detected as a 12 cm disk.
15 . The apparatus according to claim 12 , further comprising an issuing device operable to issuing a servo ON command after the accelerating and before the detecting.
16 . The apparatus according to claim 12 , wherein the first detecting device has a computer operable to count the frequency of data clock signal.
17 . The apparatus according to claim 16 , wherein the computer is an external system microcomputer which counts a clock signal produced from a digital signal processor.
18 . The apparatus according to claim 16 , wherein the computer is a servo signal processing microcomputer which counts a clock signal, and the counted result being sent to an external system microcomputer,
19 . The apparatus according to claim 12 , wherein the second detecting device detects disk diameter.
20 . The apparatus according to claim 12 , wherein the second detecting device detects disk shape.
21 . The apparatus according to claim 12 , wherein the second detecting device is operable to comparing the disk speed with a regular disk playing speed.
22 . The apparatus according to claim 12 , wherein the first detecting device is operable to find one of a plurality of ranges in which the disk speed falls in.