CN100552783C

CN100552783C - The servo balance calibrating installation and the calibration steps thereof of CD-ROM drive

Info

Publication number: CN100552783C
Application number: CNB2007101280141A
Authority: CN
Inventors: 赵志谋; 黄英峰
Original assignee: MediaTek Inc
Current assignee: MediaTek Inc
Priority date: 2006-06-23
Filing date: 2007-06-21
Publication date: 2009-10-21
Anticipated expiration: 2027-06-21
Also published as: CN101093684A

Abstract

The present invention discloses a kind of servo balance calibrating installation and calibration steps thereof of CD-ROM drive, is used to adjust the servo balance gain of CD-ROM drive, and the optical read unit of CD-ROM drive is sent light beam to CD and detecting folded light beam, to produce one group of detection signal.The servo balance calibrating installation comprises amplifying unit, servosignal generator, control module and balance alignment unit.Amplifying unit amplifies this group detection signal according to gain amplifier and forms first group of amplifying signal.The servosignal generator has this servo balance gain, produces first servosignal according to first group of amplifying signal.One of control module control optical read unit and amplifying unit are to produce second group of amplifying signal.The balance alignment unit calculates to first servosignal and from second servosignal of second group of amplifying signal, to adjust the servo balance gain of first servosignal and second servosignal.

Description

The servo balance calibrating installation and the calibration steps thereof of CD-ROM drive

[technical field]

The invention relates to a kind of servo balance calibrating installation and calibration steps thereof of CD-ROM drive, and particularly install and calibration steps relevant for a kind of rail balance calibration (tracking balance calibration) that follows of CD-ROM drive.

[background technology]

When CD-ROM drive from reading of data on the CD or write data to the CD during, the optical read unit of CD-ROM drive (optical pick-up unit, OPU) should detect reflected signal from CD constantly as servocontrol (servo control), so that optical read unit data on the access CD correctly.Optical read unit comprises the photodiode (photodiode) of detecting folded light beam, the light beam focal zone of folded light beam can't balance focus on photodiode, that is to say that the light beam focal zone is not the center at photodiode, or the light beam focal zone that detects is when can't balance focusing on, and the servocontrol of optical read unit just can't correct execution.Servo balance calibration is generally used for calculating the servo balance gain, revising above-mentioned uneven situation about focusing on, thereby makes the servocontrol can correct execution.Traditional follows rail balance calibration (tracking balance calibration) in being usually used in above-mentioned servo balance calibration steps, yet suitable complexity of traditional mode and efficient are not good.

[summary of the invention]

Fundamental purpose of the present invention is to provide a kind of servo balance calibrating installation and calibration steps thereof of CD-ROM drive, simply and expeditiously to carry out the servo balance calibration.

For realizing above-mentioned or other purpose, the present invention adopts following technical scheme: CD-ROM drive is provided with optical read unit sending light beam to a discs, and detecting is from the folded light beam of discs, to produce one group of detection signal.Servo balance calibrating installation of the present invention mainly comprises amplifying unit, servosignal generator, control module and balance alignment unit.Amplifying unit receives this group detection signal, and amplifies this group detection signal and form first group of amplifying signal according to a gain amplifier.The servosignal generator has the gain of this servo balance, in order to receiving first group of amplifying signal, and produces first servosignal according to this first group of amplifying signal.Control module is coupled to optical read unit and amplifying unit, in order to one of control optical read unit and amplifying unit, to produce second group of amplifying signal.The balance alignment unit is coupled to the servosignal generator, in order to calculate to first servosignal and from second servosignal of this second group of amplifying signal, to adjust the servo balance gain of first servosignal and second servosignal, to carry out the servo balance calibration.

Servo balance calibration steps of the present invention comprises the following step: amplify this group detection signal according to a gain amplifier, to form first group of amplifying signal.Then according to this servo balance gain, to produce first servosignal from first group of amplifying signal.Produce second group of amplifying signal subsequently.Calculate to first servosignal and from one second servosignal of this second group of amplifying signal at last, to adjust the servo balance gain of first servosignal and second servosignal, to carry out the servo balance calibration.

For above and other objects of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly, and cooperate appended graphicly, be described in detail below.

[description of drawings]

Fig. 1 is the synoptic diagram according to the servo balance calibration parameter of the adjustment CD-ROM drive in a preferred embodiment of the present invention.

Fig. 2 is the photodiode among the embodiment of Fig. 1 of the present invention and the synoptic diagram of amplifying unit.

Fig. 3 A is first servosignal among the embodiment of Fig. 1 of the present invention and the oscillogram of second servosignal, and wherein first servosignal and second servosignal form the accurate position of different direct currents according to the reference power level of optical read unit (OPU) or the gain amplifier of amplifying unit.

Fig. 3 B is the oscillogram of aiming at first servosignal and second servosignal among the embodiment of Fig. 3 A of the present invention, so that this first servosignal is identical with the accurate position of the direct current of second servosignal.

Fig. 3 C be among the embodiment of Fig. 3 A of the present invention this first servosignal and second servosignal in alignment with an oscillogram with reference to accurate position.

Fig. 4 is a process flow diagram of adjusting the servo balance calibration parameter among Fig. 1 first embodiment of the present invention according to the reference power level of optical read unit.

Fig. 5 is a process flow diagram of adjusting the servo balance calibration parameter among Fig. 1 second embodiment of the present invention according to the gain amplifier of amplifying unit.

[embodiment]

Please refer to Fig. 1, is the synoptic diagram that a preferred embodiment of the present invention is adjusted the servo balance calibration parameter of CD-ROM drive.Servo balance calibrating installation 100 of the present invention is used for CD-ROM drive, carries out the servo balance calibration in simple and efficient mode.The optical read unit of CD-ROM drive (OPU) 102 is sent light beam S _eTo CD 104 and detect folded light beam S from CD 104 _r, to produce one group of detection signal S _dIn a preferred embodiment of the present invention, the program of carrying out the servo balance calibration with servo balance calibrating installation 100 for example is to carry out to follow rail balance calibration (tracking balance calibration), to carry out the servocontrol of CD-ROM drive.

Servo balance calibrating installation 100 mainly comprises amplifying unit 106, servosignal generator 108, control module 110 and balance alignment unit 112.Amplifying unit 106 receives one group of detection signal S _d, and amplify this group detection signal S _d, to form first group of amplifying signal S _1aServosignal generator 108 has servo balance gain (servo balance gain), in order to receive first group of amplifying signal S _1a, and according to first group of amplifying signal S _1aProduce the first servosignal S _1sControl module 110 is coupled to optical read unit 102 and amplifying unit 106, and control module 110 is in order to control optical read unit 102 and amplifying unit 106 both one of them, to produce second group of amplifying signal S _2a Balance alignment unit 112 is coupled to servosignal generator 108, in order to the first servosignal S _1sAnd from second group of amplifying signal S _2aThe second servosignal S _2sProofread and correct, to adjust the first servosignal S of servosignal generator 108 _1sWith the second servosignal S _2sServo balance gain, to finish the program of servo balance calibration.

With reference to figure 1 and Fig. 2, Fig. 2 is the photodiode 114 among the embodiment of Fig. 1 of the present invention and the synoptic diagram of amplifying unit 106.The photodiode 114 of optical read unit 102 mainly is made up of 4 sections (segment), comprises section A, section B, section C and section D, and these sections A, B, C, D receive the folded light beam S from CD 104 _r, with detecting folded light beam S _rThereby, forming light beam focal zone (laser spot) 116 at section A, section B, section C and section D, the section A of photodiode 114, section B, section C and section D export detection signal S respectively _Da, S _Db, S _Dc, S _DdAmplifying unit 106 is in order to amplify detection signal S _Da, S _Db, S _Dc, S _Dd, in a preferred embodiment, control module 110 control amplifying units 106 make amplifying unit 106 amplify this group detection signal S according to its gain amplifier _Da, S _Db, S _Dc, S _Dd, to form first group of amplifying signal S _1aAnd second group of amplifying signal S _2aWith first group of amplifying signal S _1aAnd second group of amplifying signal S _2aBe sent to servosignal generator 108, to produce the first servosignal S respectively _1sAnd the second servosignal S _2sBe calibrated to example to follow the rail balance, will be from the detection signal S of photodiode 114 _Da, S _Db, S _Dc, S _DdBe divided into two groups of summations, wherein one group is detection signal S _DaWith detection signal S _DdSummation (S _Da+ S _Dd), another group is detection signal S _DbWith detection signal S _DcSummation (S _Db+ S _Dc), servosignal generator 108 calculates the difference of aforementioned two groups of detection signal summations, that is calculates (S _Da+ S _Dd) and (S _Db+ S _Dc) two groups and difference.

With reference to figure 1, Fig. 2 and Fig. 3 A, Fig. 3 A is the oscillogram according to first servosignal among the embodiment of Fig. 1 of the present invention and second servosignal, and wherein first servosignal and second servosignal are according to the reference power level of optical read unit 102 or the gain amplifier of amplifying unit is to form the accurate position of different direct currents.In 3A figure, transverse axis express time, Z-axis are represented the amplitude size of signal.

In the first embodiment of the present invention, control module 110 control optical read unit 102 so that optical read unit 102 is sent the light beam with first power, make amplifying unit 106 form first group of amplifying signal S _1aHas servo balance gain k then _bServosignal generator 108 receive first group of amplifying signal S _1a, and generation stems from first group of amplifying signal S _1aThe first servosignal S _1sControl module 110 is control optical read unit 102 further, so that optical read unit 102 is sent the light beam with second power, makes amplifying unit 106 form second group of amplifying signal S _2aThen has servo balance gain k _bServosignal generator 108 receive second group of amplifying signal S _2a, and produce the second servosignal S _2sCompared to a reference accurate position RL, the first servosignal S _1sHave first skew (offset) accurate position OL1, the second servosignal S2s has second skew accurate position OL2.In the preferred embodiment, be defined as following square formula: RL=OL1-(OL2-OL1) with reference to accurate position RL, know those skilled in the art and it should be noted, the first skew accurate position OL1 and second skew accurate position OL2 ratio between the two can be arbitrary values.According to above-described content, control module 110 step control optical read unit 102, so that optical read unit 102 is sent the light beam of different capacity, the amplifying signal that amplifying unit 106 is formed have the different accurate positions of skew (for example OL1, OL2) (S for example _1s, S _2s).

In the present invention, the first servosignal S _1sAnd the second servosignal S _2sWith following formulate:

(S _1sOr S _2s)=k _b* (S _Da+ S _Dd)-(S _Db+ S _Dc) ... ... ... (1)

K wherein _bBe the servo balance gain of servosignal generator 108, and S _Da=PR*a, S _Db=PR*b, S _Dc=PR*c, S _Dd=PR*d.

Therefore in first embodiment, formula (1) is expressed as follows:

(S _1sOr S _2s)=PR[k _b(a+d)-(b+c)] ... ... ... (2)

Wherein PR is the laser power of optical read unit 102, for example is the readout power (reading power) of optical read unit 102, and the PR value is adjustable value, a, and b, c, d are and detection signal S _Da, S _Db, S _Dc, S _DdThe electronic signal that is associated.

In the second embodiment of the present invention, amplifying unit 106 is according to gain amplifier k _PdDetection signal from optical read unit 102 is amplified, to produce first group of amplifying signal S _1a, gain amplifier k wherein _PdIt for example is lower yield value.Has servo balance gain k _bServosignal generator 108 receive first group of amplifying signal S _1a, and generation stems from first group of amplifying signal S _1aThe first servosignal S _1sAmplifying unit 106 is further according to gain amplifier k _PdDetection signal from optical read unit 102 is amplified, to produce second group of amplifying signal S _2a, gain amplifier k wherein _PdIt for example is higher yield value.Has servo balance gain k _bServosignal generator 108 produce and stem from second group of amplifying signal S _2aThe second servosignal S _2sCompared to the accurate position of reference RL, the first servosignal S _1sHas first skew accurate position OL1, the second servosignal S _2sHas second skew accurate position OL2.According to above-mentioned explanation, control module 108 is adjusted the gain amplifier k of amplifying unit 106 _Pd, with first group of amplifying signal S _1aBe adjusted to second group of amplifying signal S _2a, the amplifying signal that makes servosignal generator 108 produce to have the accurate positions of different direct current offsets (for example OL1, OL2) (S for example _1s, S _2s).

Similarly, in a second embodiment, formula (1) can be expressed as follows:

(S _1sOr S _2s)=k _Pd[k _b(a+d)-(b+c)] ... ... ... (3)

S wherein _Da=k _Pd* a, S _Db=k _Pd* b, S _Dc=k _Pd* c, S _Dd=k _Pd* d, and gain amplifier k _PdCan adjust, a, b, c, d are and detection signal S _Da, S _Db, S _Dc, S _DdThe electronic signal that is associated.

With reference to figure 1, Fig. 3 A and Fig. 3 B, Fig. 3 B is according to the oscillogram of aiming at first servosignal and second servosignal among the embodiment of Fig. 3 A of the present invention, so that this first servosignal is identical with the accurate position of the direct current of second servosignal.In Fig. 3 B, transverse axis express time, Z-axis are represented the amplitude size of signal.

Control module 110 control optical read unit 102 so that optical read unit (102 send the light beam with first power, make servosignal generator 108 form the first servosignal S _1sControl module 110 is control optical read unit 102 further, so that optical read unit 102 is sent the light beam with second power, makes servosignal generator 108 form the second servosignal S _2sIn addition, control module 110 control amplifying units 106 make amplifying unit 106 according to gain amplifier k _PdAmplify detection signal, to produce first group of amplifying signal S _1a, gain amplifier k wherein _PdFor example be than the low gain value, servosignal generator 108 is according to first group of amplifying signal S _1aForm the first servosignal S _1sControl module 110 control amplifying units 106 make amplifying unit 106 according to gain amplifier k _PdAmplify detection signal, to produce second group of amplifying signal S _2a, gain amplifier k wherein _PdFor example be higher gain value, servosignal generator 108 is according to second group of amplifying signal S _2aForm the second servosignal S _2s

Balance alignment unit 112 is the first skew accurate position OL1 and second skew accurate position OL2 relatively, to judge whether first skew accurate position OL1 is identical with second skew accurate position OL2, when first skew accurate position OL1 inequality with the accurate OL2 of second skew, or when difference was greater than a predetermined offset value (predetermined offset threshold) between first skew accurate position OL1 and the second skew accurate position OL2, balance alignment unit 112 was by the aligning first servosignal S _1sWith the second servosignal S _2s, to continue to adjust the servo balance gain k of servosignal generator 108 _b, identical until first skew accurate position OL1 with second skew accurate position OL2, or difference is less than a predetermined offset value between the first skew accurate position OL1 and the second skew accurate position OL2.In other words, the first servosignal S _1sWith the second servosignal S _2sHave identical or accurate position, the center that is close.

With reference to figure 1, Fig. 3 A and Fig. 3 C, Fig. 3 C is in alignment with an oscillogram with reference to accurate position according to this first servosignal and second servosignal among the embodiment of Fig. 3 A of the present invention.Be similar to Fig. 3 B, servosignal generator 108 forms the first servosignal S respectively according to the light beam with first power and second power _1sAnd the second servosignal S _2sAmong another embodiment, servosignal generator 108 produces the first servosignal S according to lower yield value _1s, and higher yield value produces the second servosignal S _2s

Balance alignment unit 112 is the first skew accurate position OL1 and second skew accurate position OL2 relatively, to judge whether first skew accurate position OL1 is identical with second skew accurate position OL2, when first skew accurate position OL1 inequality with the accurate OL2 of second skew, or the accurate OL1 of first skew and second is offset when difference is greater than a predetermined offset value (predetermined offset threshold) between the accurate position OL2, and balance alignment unit 112 is by the aligning first servosignal S _1sWith the second servosignal S _2s, to continue to adjust the servo balance gain k of servosignal generator 108 _b, identical until first skew accurate position OL1 with second skew accurate position OL2, or difference is less than a predetermined offset value between the first skew accurate position OL1 and the second skew accurate position OL2.In the preferred embodiment, the proportionality between first skew accurate position OL1 and the accurate OL2 of second skew in this way 1/2, and this ratio can be by laser power or gain amplifier value k _PdDecision.Be defined as following square formula: RL=OL1-(OL2-OL1) with reference to accurate position RL, those skilled in the art it should be noted that first skew accurate position OL1 of the present invention and second skew accurate position OL2 ratio between the two can be arbitrary value.

With reference to figure 1 and Fig. 4, Fig. 4 is according to the process flow diagram of adjusting the servo balance calibration parameter among Fig. 1 first embodiment of the present invention according to the reference power level of optical read unit 102.The present invention carries out the step of servo balance calibration steps, and is as described below:

In step S400, control module 110 is set at first power with the laser power reference position value of optical read unit 102.In step S402, optical read unit 102 is sent the light beam with first power.In step S404, has servo balance gain k _bServosignal generator 108 produce the first servosignal S corresponding to first power _1sIn step S406, control module 110 control servosignal generators 108 are to measure the first servosignal S _1sFirst skew accurate position OL1.

In step S408, control module 110 is set at second power with the laser power reference position value of optical read unit 102.In step S410, optical read unit 102 is sent the light beam with second power.In step S412, has servo balance gain k _bServosignal generator 108 produce the second servosignal S corresponding to second power _2sIn step S414, control module 110 control servosignal generators 108 are to measure the second servosignal S _2sSecond skew accurate position OL2.

In step S416, balance alignment unit 112 is the first skew accurate position OL1 and second skew accurate position OL2 relatively, to judge whether first skew accurate position OL1 is identical with second skew accurate position OL2, when judged result is " be ", then finish the step of servo balance calibration, produce needed servo balance yield value.When judged result is " deny ", then balance alignment unit 112 is adjusted the servo balance gain of servosignal generator 108, and be back to step S400, to continue to adjust the servo balance gain, identical until first skew accurate position OL1 with second skew accurate position OL2, or difference is less than a predetermined offset value, to finish the step of servo balance calibration between accurate OL1 of first skew and the second skew accurate position OL2.

With reference to figure 1 and Fig. 5, Fig. 5 is according to the process flow diagram of adjusting the servo balance calibration parameter among Fig. 1 second embodiment of the present invention according to the gain amplifier of amplifying unit.The present invention carries out the step of servo balance calibration steps, and is as described below:

In step S500, control module 110 is set at a predetermined power with the laser power reference position value of optical read unit 102.In step S502, optical read unit 102 produces one group of detection signal according to this predetermined power.

In step S504, amplifying unit 106 amplifies the detection signal from optical read unit 102 according to gain amplifier, to produce first group of amplifying signal S _1a, gain amplifier k wherein _PdFor example be than the low gain value.In step S506, has servo balance gain k _bServosignal generator 108 receive first group of amplifying signal S _1a, and generation stems from first group of amplifying signal S _1aThe first servosignal S _1sIn step S508, control module 110 control servosignal generators 108 are to measure the first servosignal S _1sFirst skew accurate position OL1.

In step S510, amplifying unit 106 is according to gain amplifier k _PdDetection signal from optical read unit 102 is amplified, to produce second group of amplifying signal S _2a, gain amplifier k wherein _PdIt for example is higher yield value.In step S512, has servo balance gain k _bServosignal generator 108 produce and stem from second group of amplifying signal S _2aThe second servosignal S _2sIn step S514, control module 110 control servosignal generators 108 are to measure the second servosignal S _2sSecond skew accurate position OL2.

In step S516, balance alignment unit 112 is the first skew accurate position OL1 and second skew accurate position OL2 relatively, to judge whether first skew accurate position OL1 is identical with second skew accurate position OL2, when judged result is " be ", finish the step of servo balance calibration, produce needed servo balance yield value.When judged result is " deny ", balance alignment unit 112 is adjusted the servo balance gain of servosignal generator 108, and be back to step S504, to continue to adjust the servo balance gain, identical until first skew accurate position OL1 with second skew accurate position OL2, or difference is less than a predetermined offset value, to finish the step of servo balance calibration between accurate OL1 of first skew and the second skew accurate position OL2.

Main feature of the present invention comprises: (a) carry out simply the servo balance calibration of CD-ROM drive; And (b) By adjusting laser power and the gain amplifier value corresponding to servosignal, servo flat to carry out efficiently The weighing apparatus calibration.

Claims

1. the servo balance calibrating installation of a CD-ROM drive, in order to adjust the servo balance gain of CD-ROM drive, described CD-ROM drive is provided with optical read unit in order to send light beam to a CD, and detecting is from the folded light beam of this CD, to produce one group of detection signal, the servo balance calibrating installation of this CD-ROM drive comprises at least: an amplifying unit, one servosignal generator, one control module and a balance alignment unit, wherein amplifying unit is in order to receive aforementioned group of detection signal, and amplify aforementioned group of detection signal and form one first group of amplifying signal, the servosignal generator has this servo balance gain, in order to receive this first group of amplifying signal, and produce one first servosignal according to this first group of amplifying signal, it is characterized in that: this control module is coupled to this optical read unit and this amplifying unit, in order to control one of this optical read unit and this amplifying unit, to produce one second group of amplifying signal, this balance alignment unit is coupled to this servosignal generator, in order to this first servosignal and stem from this second group of amplifying signal and one second servosignal that produces calculates, to adjust the servo balance gain of this first servosignal and this second servosignal, to carry out the servo balance calibration.

2. the servo balance calibrating installation of CD-ROM drive as claimed in claim 1, it is characterized in that: this control module is adjusted the gain amplifier of this amplifying unit, forms this second group of amplifying signal to adjust this first group of amplifying signal.

3. the servo balance calibrating installation of CD-ROM drive as claimed in claim 1, it is characterized in that: this control module is controlled this optical read unit, so that this optical read unit is sent the light beam with first power, make this amplifying unit form this first group of amplifying signal, and this control module is controlled this optical read unit, so that this optical read unit is sent the light beam with second power, make this amplifying unit form this second group of amplifying signal.

4. the servo balance calibrating installation of CD-ROM drive as claimed in claim 1, it is characterized in that: this balance alignment unit is adjusted the servo balance gain of this servosignal generator, to aim at this first servosignal and this second servosignal, make this first servosignal and this second servosignal have the accurate position of identical direct current.

5. the servo balance calibrating installation of CD-ROM drive as claimed in claim 1 is characterized in that: this servo balance calibration is to follow the calibration of rail balance.

6. the servo balance calibration steps of a CD-ROM drive, in order to adjust the servo balance gain of CD-ROM drive, this CD-ROM drive is provided with optical read unit to send light beam to a CD, and detecting is from the folded light beam of this CD, to produce one group of detection signal, the servo balance calibration steps of this CD-ROM drive comprises the following step at least:

Amplify this group detection signal according to a gain amplifier, to form one first group of amplifying signal;

According to this servo balance gain, stem from one first servosignal of this first group of amplifying signal with generation;

Produce one second group of amplifying signal; And

This first servosignal and one second servosignal that stems from this second group of amplifying signal are calculated, to adjust the servo balance gain of this first servosignal and this second servosignal, to carry out the servo balance calibration.

7. the servo balance calibration steps of CD-ROM drive as claimed in claim 6 is characterized in that: producing in the step of this second group of amplifying signal is by adjusting this gain amplifier, forming this second group of amplifying signal to adjust this first group of amplifying signal.

8. the servo balance calibration steps of CD-ROM drive as claimed in claim 6, it is characterized in that: this optical read unit send have first power light beam to form this first group of amplifying signal, and the step that produces this second group of amplifying signal is by controlling this optical read unit, so that this optical read unit is sent the light beam with second power, to form this second group of amplifying signal.

9. the servo balance calibration steps of CD-ROM drive as claimed in claim 6, it is characterized in that: adjust this servo balance gain, in order to aim at this first servosignal and this second servosignal, make this first servosignal and this second servosignal have the accurate position of identical direct current.

10. the servo balance calibration steps of CD-ROM drive as claimed in claim 6 is characterized in that: this servo balance calibration is to follow the calibration of rail balance.