CN1062674C - Laser beam modulation apparatus - Google Patents
Laser beam modulation apparatus Download PDFInfo
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- CN1062674C CN1062674C CN95116447A CN95116447A CN1062674C CN 1062674 C CN1062674 C CN 1062674C CN 95116447 A CN95116447 A CN 95116447A CN 95116447 A CN95116447 A CN 95116447A CN 1062674 C CN1062674 C CN 1062674C
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- signal
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- laser beam
- modulation
- pulsed modulation
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Abstract
To obtain a recording area without teardrop-like area by controlling a laser beam by a PM-EFM signal, heating the recording area of a sufficient time phase change for phase change, and then intermittently emitting the beam. The laser beam modulator comprises an EFM signal input unit 10 for receiving the 8-14 modulated signal, and a clock pulse generator 20 for generating a reference sampling clock pulse having a predetermined period of 4.32MHz. The EFM signal represents digital data to be written on a rewritable optical disk by using a laser beam, and has ON and OFF times of repetition of a series of high and low level signals. The beam is controlled by the length of the ON and OFF times of the signal.
Description
The present invention relates to a kind of optical disc recording apparatus that is used on CD-RW, writing arbitrary data; Be particularly related to a kind of laser beam modulation apparatus that uses the phase-change recording method on CD-RW, to write down numerical data.
Usually, compare with traditional tape or disk, optical record medium has many advantages, and it has and is expansion phase of service time ability with high record density and good reliability stores binary data.The example of such optical recording media includes magnetic one CD, the phase change disk that is designed to the data/information of storing under the optical readable condition, and Write once and read is storer and compact-disc repeatedly.Wherein, the characteristic of magnetic one CD and phase change disk also is the attendant advantages of data erasability and rewriting property, and this makes them compare more attractive with the optical recording media of other form.
As everyone knows, numerical data is that radiation by laser beam is written on the recording layer of these CD-RW.Magnetic one CD is with the heat of laser beam generation and the magnetization characteristic record data of last magnetic recording layer thereof.On the other hand, phase change disk is by using phase-change recording technical notes data, in this technology, laser beam by intensity modulated so that the recording layer of its crystallization through the phase transformation between mutually of crystalline state and amorphous state.Such modulation generally is to be finished by the modulating system that is commonly called FFM (eight to 14 modulation) system.The EFM system modulates will represent that by modulated laser beam for example the modulated data-signal of the numerical data of EFM signal is recorded on the CD laser beam.
But, in the phase-change recording technology, as shown in Figure 3, because the thermal diffusion of laser beam, on the posting field 72 of the crystallization of phase change disk 70, may produce teardrop 76 and cause the rising of recording error rate.
In order to overcome above-mentioned defective, oneself makes efforts and has found to reduce the requirement of Laser Power Devices to prevent the method for the thermal diffusion on the posting field.Yet, in this case,, have the shortest bit length owing to can not offer the laser of the desired level of this posting field, for example the posting field of 3T may become unstable, and T represents a time clock cycle here.
Therefore, one object of the present invention is to provide a kind of at the laser beam modulation apparatus of may command laser beam during the recording operation with the thermal diffusion on the recording areas of minimizing in CD-RW.
Another object of the present invention is to be provided for controlling the laser beam modulation apparatus that has simple circuit structure of laser beam.
According to the present invention, provide a laser beam modulation apparatus that is used to control laser beam, wherein laser beam was controlled at interval by turn-on time that is recorded in the modulated data-signal on the CD-RW and trip time, and this device comprises:
Be used to generate the first window pulse width with a fixed time period, forbid the device of window signal with the synchronous pulsed modulation of each forward conversion of modulated data-signal, wherein this pulsed modulation forbids that window signal forbids the pulsed modulation of the signal of modulated data during first window width of fixed time period;
Be used to use xor operation to forbid that in the paired pulses modulation of interim turn-on time window signal and modulated data carry out logical combination to produce a device with pulsed modulation permission window signal of the second window pulse width, wherein this pulsed modulation permits window signal to allow the modulation of modulated data-signal during the second window pulse width;
Be used to generate the device of time clock with a predetermined period;
Be used on time clock and pulsed modulation permission window signal, carrying out a logical multiplication to produce the device of a modulated pulse signal; And
Be used to carry out modulated pulse signal and pulsed modulation and forbid that the logical addition of window signal is to produce the device of a laser beam control signal.
By to the description below in conjunction with the preferred embodiment of accompanying drawing, above-mentioned and other purpose of the present invention and feature will become obviously, in the accompanying drawing:
Fig. 1 shows the block scheme according to laser beam modulation apparatus of the present invention;
Fig. 2 A to 2G represents the waveform that each several part generated of laser beam modulation apparatus shown in Figure 1 respectively;
Fig. 3 is the enlarged drawing of explanation generation of teardrop on the recording areas of CD-RW.
With reference to Fig. 1, the block scheme of the laser beam modulation apparatus of with good grounds may command intensity of laser beam of the present invention is shown.Shown this laser beam modulation apparatus comprises that an input block 10 is to receive eight-14 modulated (" EFM ") pulse signals and to be used to generate the time clock maker 20 that has just like the predetermined period one benchmark sampling clock pulse of the 432MHz frequency shown in Fig. 2 A.This EFM signal indication is recorded on the CD-RW of phase change disk for example high the and numerical data of forming at interval low level turn-on time and trip time by a sequential logic by using laser beam.This laser beam is by controlling at interval the turn-on time and the trip time of this EFM signal.Shown in Fig. 2 B, may have the length from 3T to 11T the turn-on time in this EFM signal at interval, and in this period, laser beam is radiated on the phase change disk synchronously to write down numerical data with time clock, in Fig. 2 B, this EFM signal is specified interval turn-on time that has 3T and 7T.
This EFM pulse signal is provided for the first input end that window signal maker 30 and pulsed modulation permission window signal maker 40 are forbidden in a pulsed modulation.This pulsed modulation forbids that window signal maker 30 includes the time constant circuit that a monostable circuit or an one shot multivibrator 32 and have capacitor 34 and variohm 36.This pulsed modulation forbids that each forward conversion of window signal maker 30 and EFM signal synchronously generates a pulsed modulation with window pulse width of a fixed time period " tp " and forbids window signal " PMPW ", shown in Fig. 2 C.This fixed time period tp is determined by time constant circuit usually.During fixed time period tp, the modulation of EFM signal be under an embargo so that bombardment with laser beams on the recording areas of the crystallization of phase change disk.According to the present invention, this fixed time period preferentially is arranged on to be sure of can heat fusing point level that reaches desired and the 1.5T that forms an amorphous state phase fully to recording areas by laser beam.This pulsed modulation forbids that window signal PMPW is provided for the first input end that pulsed modulation is permitted second input end of window pulse maker 40 and offered modulated pulse signal maker 60 by a delay circuit 42 then.
Forbid that by-pulsed modulation that exclusive-OR gate constituted permission window signal maker 40 paired pulses modulation thereby window signal PMPW and EFM signal carry out the exclusive OR operation and generate the window with the logic high shown in Fig. 2 D window pulse PMW is permitted in (3T-tp) and a pulsed modulation (3T-tp) at interval.This pulsed modulation permission window signal PMW allows the modulation of the EFM signal in each window interval.This pulsed modulation permission window signal is provided for the first input end of pulse-modulated signal maker 50.Wherein time clock is provided for 50 second input end by delay circuit 22.
Include one and carry out logical combination to generate with multiplication paired pulses modulation permission window signal PMW and time clock CK just like the modulated pulse signal shown in Fig. 2 E with pulse-modulated signal maker 50 utilization of circuit.Fed then second input end of the modulated pulse EFM signal generator 60 that constitutes by an OR circuit of this modulated pulse signal.
At modulated pulse EFM signal generator 60, utilization or operation forbid that to modulated pulse signal PM and pulsed modulation window signal PMPW carries out logical combination to obtain just like the modulated pulse EFM signal " PM-EFM " shown in Fig. 2 F.Subsequently, the turn-on time of 3T in the EFM signal or 7T length every during.This modulated pulse EFM signal has one to be kept for pulsed modulation and to forbid the first of EFM signal of window width tp and the second portion of afterpulsing modulation permission window time clock at interval.This first segment pulse is used for being used to make laser beam to produce fluctuation to prevent the overheated of recording areas the recording areas and second segment pulse that laser beam imposes on the CD.Therefore, when modulated pulse EFM signal PM-EFM is provided for a laser power driver as a laser power control signal, laser beam is controlled by this way by modulated pulse EFM signal PM-EFM, make recording areas by abundant heating with the 1.5T that stands to be used for the EFM signal at interval phase transformation and in each interim turn-on time of EFM signal, heat is provided to convert recording areas to decrystallized state, thereby prevents the heating that the laser beam by diffusion overwriting district causes.Like this, may obtain not have the desired recording areas of teardrop problem, shown in Fig. 2 G, thereby improve the recording error rate.
Though show with respect to certain embodiments and described the present invention, for person skilled in the art person, obviously can make many changes and correction not breaking away under defined invention spirit of appending claims and the scope.
Claims (3)
1, a kind of laser beam modulation apparatus that is used to control laser beam, wherein laser beam was controlled at interval by turn-on time that is recorded in the modulated data-signal on the CD-RW and trip time, and this device comprises:
Be used to generate the first window pulse width with a fixed time period, forbid the device of window signal with the synchronous pulsed modulation of each forward conversion of modulated data-signal, wherein this pulsed modulation forbids that window signal forbids the pulsed modulation of the signal of modulated data during first window width of fixed time period;
Be used to use xor operation to forbid that in the paired pulses modulation of interim turn-on time window signal and modulated data carry out logical combination to produce a device with pulsed modulation permission window signal of the second window pulse width, wherein this pulsed modulation permits window signal to allow the modulation of modulated data-signal during the second window pulse width;
Be used to generate the device of time clock with a predetermined period;
Be used on time clock and pulsed modulation permission window signal, carrying out a logical multiplication to produce the device of a modulated pulse signal; And
Be used to carry out modulated pulse signal and pulsed modulation and forbid that the logical addition of window signal is to produce the device of a laser beam control signal.
2, according to the device of claim 1, wherein pulsed modulation forbids that the window signal generating apparatus includes an one shot multivibrator and a time constant circuit to determine first window width of fixed time period.
3, according to the device of claim 2, wherein fixed time period duration of being set an abundance heats so that recording areas changed into amorphous state from crystalline state the recording areas of a crystallization on the CD-RW by laser beam.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR22215/1994 | 1994-09-05 | ||
| KR22215/94 | 1994-09-05 | ||
| KR94022215A KR0134293B1 (en) | 1994-09-05 | 1994-09-05 | Laser power modulation apparatus using phase change for an |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1148239A CN1148239A (en) | 1997-04-23 |
| CN1062674C true CN1062674C (en) | 2001-02-28 |
Family
ID=19391989
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN95116447A Expired - Fee Related CN1062674C (en) | 1994-09-05 | 1995-09-05 | Laser beam modulation apparatus |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP2969065B2 (en) |
| KR (1) | KR0134293B1 (en) |
| CN (1) | CN1062674C (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0185557A2 (en) * | 1984-12-21 | 1986-06-25 | Sony Corporation | Optical modulation systems |
-
1994
- 1994-09-05 KR KR94022215A patent/KR0134293B1/en not_active IP Right Cessation
-
1995
- 1995-09-05 CN CN95116447A patent/CN1062674C/en not_active Expired - Fee Related
- 1995-09-05 JP JP7251793A patent/JP2969065B2/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0185557A2 (en) * | 1984-12-21 | 1986-06-25 | Sony Corporation | Optical modulation systems |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2969065B2 (en) | 1999-11-02 |
| KR0134293B1 (en) | 1998-04-22 |
| JPH08212553A (en) | 1996-08-20 |
| CN1148239A (en) | 1997-04-23 |
| KR960011869A (en) | 1996-04-20 |
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Effective date of registration: 20030523 Patentee after: Daewoo Electronics Co., Ltd. Patentee before: Daewoo Electronics Co., Ltd. |
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| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |