CN1337678A

CN1337678A - Optical head track seeking method for CD drive

Info

Publication number: CN1337678A
Application number: CN 00121224
Authority: CN
Inventors: 蔡耀州
Original assignee: Lite On IT Corp
Current assignee: Lite On IT Corp
Priority date: 2000-08-07
Filing date: 2000-08-07
Publication date: 2002-02-27
Anticipated expiration: 2020-08-07
Also published as: CN1133990C

Abstract

The present invention relates to a track-searching method for optical head of optical drive, and is characterized by that in the operation of searching track of disk it utilizes the number, size and direction of track for fine adjustment searching track to regulate coarse adjustment for searching track to control voltage waveform to overcome the optical drive variation resulted from mechanism friction and motor torque and obtain the coarse adjustment track-searching accuracy identical to that of mounted speed inductor. In the course of production it can greatly reduce cost.

Description

The track seeking method of CD-ROM drive optical head

The track seeking method of the relevant a kind of CD-ROM drive optical head of the present invention, it is by a kind of learning-oriented track seeking method, overcomes this CD-ROM drive because the variation of mechanism's friction and motor torsional moment reaches coarse adjustment and seeks the rail degree of accuracy.

The trailer structure that follows of CD-ROM drive is that laser beam is passed through track on object lens (the Object ive lens) tracking disc and optical head and followed object lens and finish.In the time will searching arbitrary track of this disc, on the practice, be generally by two actions: (1), first flying optical head near goal track, (2), make laser beam arrive goal track via object lens fine settings again.First element (1) is referred to as coarse adjustment and seeks rail (roughseek); Second action (2) is referred to as fine setting and seeks rail (fine seek).Desiring to reach this coarse adjustment and seek the rail degree of accuracy, is that assembling one speed sensor and the FEEDBACK CONTROL of arranging in pairs or groups are finished, because this speed sensor is quite expensive, so do not meet cost consideration.

See also the mechanism of general CD-ROM drive 1 shown in Figure 1, motor 12 on it is to drive optical head 14 by gear set or guide screw stalk 13, when searching beginning, this microprocessor (not shown) can be sent a control waveform (as shown in Figure 2) and drive optical head 14, by the static constant speed district that accelerates to, be decelerated to static again.The deviser can formulate voluntarily optical head cross over several rails (quicken the rail number, accelerationtrack) after, switch to (max speed) the most at a high speed, with constant-speed driving.Generally speaking, this does not have any problem (as increasing search time) takes place, however residue rail number (deceleration rail number, what decelcration track) for time just reduce speed now, and can follow rail smoothly when control voltage finishes, and prepare to carry out fine setting and seek rail, be the thing of a difficulty.Because it is excessive that the motor that mechanism that friction force is little or moment of torsion are bigger can cause coarse adjustment to seek rail, and big mechanism or the less motor of moment of torsion of friction force can cause coarse adjustment to seek the rail deficiency.

Above-mentionedly either way can increase this fine setting and seek the required rail number of rail, just, increase whole search time (Access time).

The purpose of this invention is to provide a kind of CD-ROM drive optical head track seeking method, this method is a learning-oriented track seeking method, to overcome the variation of CD-ROM drive because of mechanism's friction and motor torsional moment, reaches the coarse adjustment same with installing speed sensor and seeks the rail degree of accuracy.It is in the action of the track of searching disc, and size counted by the rail that utilizes fine setting to seek rail and direction is adjusted the control waveform that rail is sought in coarse adjustment, if the direction that rail is sought in fine setting; Otherwise, opposite if rail is sought in the direction that rail is sought in fine setting and coarse adjustment, and the rail number that rail is sought in this fine setting surpasses the design tolerable error, and the rail number that then slows down can increase by one and learn spacing.

Another object of the present invention provides a learning-oriented optical head track seeking method, its design of mat, can quicken the rail number with the most at a high speed, also can list learning parameter in the hope of optimization.

Another purpose of the present invention provides a learning-oriented optical head track seeking method, because it need not install speed sensor in the following in the trailer structure of CD-ROM drive, so can significantly reduce cost on manufacture process.

The track seeking method of CD-ROM drive optical head of the present invention is achieved in that it is in the action of the track of searching video disc, and size counted by the rail that utilizes fine setting to seek rail and direction is adjusted the control waveform that rail is sought in coarse adjustment.

The learning parameter of control waveform includes and quickens rail number, the most at a high speed and deceleration rail number.

It is identical that rail is sought in the direction that rail is sought in fine setting and coarse adjustment, and the rail number that rail is sought in fine setting surpasses design tolerable error (fine seek tolerance), and the rail number that then slows down can reduce one and learn spacing (learninggap).

It is opposite that rail is sought in the direction that rail is sought in fine setting and coarse adjustment, and the rail number that rail is sought in fine setting surpasses the design tolerable error, and the rail number that then slows down can increase by one and learn spacing.

Describe feature of the present invention and technology contents in detail below in conjunction with accompanying drawing:

Fig. 1 is the mechanism map of general CD-ROM drive.

Fig. 2 is the oscillogram that rail control voltage is sought in coarse adjustment.

Fig. 3 is that rail that the present invention utilizes fine setting to seek rail is counted size and direction is adjusted the process flow diagram that rail is sought in coarse adjustment.

The present invention is a kind of track seeking method of CD-ROM drive optical head, and it is in the action of the track of searching disc, and size counted by the rail that utilizes the counting fine setting to seek rail and direction is adjusted the voltage waveform that rail is sought in coarse adjustment, as shown in Figure 3.

See also Fig. 3, at the beginning, move near this optical head (rail is sought in coarse adjustment) 31 goal track, it is several 32 that the rail of rail is sought in the counting fine setting, differentiate deceleration rail number and whether surpass the tolerable error (fine seek tolerance) that the rail design is sought in this fine setting? 33.If do not surpass then power cut-off; Do you if surpass, then differentiate fine setting and seek the rail direction and be same as coarse adjustment and seek rail? 34.If it is identical that rail is sought in the direction that rail is sought in fine setting and coarse adjustment, the rail number that then slows down can reduce one and learn spacing (learning gap) 35; If it is opposite that rail is sought in the direction that rail is sought in fine setting and coarse adjustment, the rail number that then slows down can increase by one and learn spacing 36.

Therefore, when searching disc track action generation, it is repetition learning so, the rail of seeking rail until fine setting scolds that study action side stops within the design tolerable error, if Yin Wendu changes, and the rail number that causes fine setting to seek rail surpasses the design tolerable error, and then the study action can restart in seek actions again.In fact quicken rail number (acceleration track) and also can list learning parameter in the hope of optimization with the most at a high speed (max speed).

In sum, by the learning-oriented optical head track seeking method of the present invention, have characteristics described as follows:

(1), can overcome this CD-ROM drive because of the variation of mechanism friction and motor torsional moment, reach and installing speed The rail accuracy is sought in the same coarse adjustment of inductor.

(2), since its not be used in CD-ROM drive follow rail mechanism installing speed sensor, thereby making Cheng Shangke significantly reduces cost.

Claims

1, a kind of track seeking method of CD-ROM drive optical head is characterized in that: be in the action of the track of searching video disc, size counted by the rail that utilizes fine setting to seek rail and direction is adjusted the control waveform that rail is sought in coarse adjustment.

2, the track seeking method of CD-ROM drive optical head as claimed in claim 1 is characterized in that: the learning parameter of control waveform includes and quickens rail number, the most at a high speed and deceleration rail number.

3, the track seeking method of CD-ROM drive optical head as claimed in claim 1 is characterized in that: it is identical that rail is sought in the direction that rail is sought in fine setting and coarse adjustment, and the rail number that rail is sought in fine setting surpasses the design tolerable error, and the rail number that then slows down can reduce one and learn spacing.

4, the track seeking method of CD-ROM drive optical head as claimed in claim 1 is characterized in that: it is opposite that rail is sought in the direction that rail is sought in fine setting and coarse adjustment, and the rail number that rail is sought in fine setting surpasses the design tolerable error, and the rail number that then slows down can increase by one and learn spacing.