CN1819039A

CN1819039A - Media and device for optical information recording and display device

Info

Publication number: CN1819039A
Application number: CN 200610006007
Authority: CN
Inventors: 前川博史
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2002-09-04
Filing date: 2003-09-04
Publication date: 2006-08-16
Anticipated expiration: 2023-09-04
Also published as: CN100369126C; JP4138410B2; CN100423096C; CN1822131A; JP2004103048A

Abstract

A multilevel information recording apparatus is disclosed. A multilevel information recording apparatus, which includes a control unit that inputs signals to a strategy generating unit and a laser drive unit based on the multilevel information being recorded, a signal indicating the playback and recording state, and a clock signal indicating the cell frequency that is in synch with the multilevel information. The strategy generating unit generates a pulse signal in accordance with the timing of the laser beam emission of a write pulse, an off pulse, a bias pulse, and a space pulse based on the signal from the control unit and the clock signal. The laser drive unit determines the driving current of a laser light source based on a delayed playback signal/delayed recording signal that is obtained by delaying the playback signal/recording signal for a processing time of the strategy generating unit, a pulse signal from the strategy generating unit indicating the emission timing of the pulses, and an intensity signal predetermined for each pulse.

Description

Optical information recording medium, pen recorder and playing device

Present patent application is to be that September 4, application number in 2003 are 03127285.1, are entitled as the dividing an application of patented claim of " optic recording method, device and medium, laser control circuit, signal detecting method " applying date.

Technical field

The present invention relates to a kind of at optical information recording medium, for example the light information recording method of the multistage information of record (multilevel information) on the CD, carry out the device for optical information recording of this light information recording method, for example the laser control circuit of the radiation of optical disc apparatus, control laser beam, be used in the wobble signal detection method of multi-level recording wobble detection signal and the servosignal detection method that is used for detecting servosignal at multi-level recording.

Background technology

At present, CD driver and the conduct of DVD driver are used at optical information recording medium, and for example the device for optical information recording of CD or DVD identifying recording layer has obtained generally acknowledging.Simultaneously, it is increasing that the size of data of processed file is just becoming, and therefore, just requires to have higher performance to obtain bigger capacity on optical information recording medium in device for optical information recording.

A method that increases the capacity of optical information recording medium is to use multi-level recording technology (for example, Jap.P. discloses 2001-84592 number).According to this multi-level recording technology, the unit that has predetermined length on the circumferencial direction of CD track is defined as virtual record unit (cell), with laser beam irradiation on the described unit in case on each unit record mark.Here, the circumferencial direction length of described unit does not exceed the optical resolution of light beam spot usually.Information is included in the area that is recorded in the mark on each unit.By the area according to each mark is distinguished from a plurality of level of the signal of these unit reflections, can extract multistage information from described unit.

In the CD driver or DVD driver of traditional use twin-stage information recording method, information is embedded in the record mark that has greater than the length of optical resolution.Therefore, according to this method, the restriction that reduces beam spot diameter has been hindered the jumbo realization of CD.Especially, beam spot diameter is that the numerical aperture (NA) of wavelength and lens by laser beam is determined by physical principle.Therefore, attempt reduces the NA that beam spot diameter must depend on the wavelength of increase laser shortwave and increase lens.On the other hand, according to multistage information recording method, multistage information is recorded on the unit that has with the optical resolution equal lengths, and therefore, the capacity of CD can be reduced, and does not reduce beam spot and can not depend on.

Typically be used to use the laser emitting waveform of the multistage information record of phase change medium to comprise to have the highlight strength of the recording layer that is used to melt optical information recording medium write pulse, have and be used for cooling off fast recording layer with low (off) pulse of the low light intensity that forms mark be used for forming the spacing pulse of (perhaps being used under rewritable situation, wiping the mark that has existed) at interval on the recording layer.

In this example, the low-yield cycle has taken most of label information time, and the light emission is very weak in this cycle.That is, the light intensity in low-yield cycle is set to and is not more than the broadcast energy.Especially, the light intensity immediately following the low-yield cycle after writing energy cycle is preferably set to low as much as possible so that strengthen cooling effect (even may not having the light emission) at all.Yet, when laser beam is output as when low, owing to increased noise by the instability of the light emission state that causes from the influence of returning (reflection) light.In addition, reflected signal strength has also been weakened, thereby has caused from the weakness such as the influence of the such factor of circuit noise.

Usually, in playing process, play energy and must be set to relatively low to prevent that mark is aging.Therefore, for example, can use the high-frequency modulator (HFM) that can reduce the laser beam noise, perhaps can increase the magnification of first order testing circuit so that guarantee enough signal amplitudes and component of signal and not be subjected to the circuit noise jamming.

On the other hand, in recording process, in order in writing energy cycle or interval energy cycle, to prevent the saturated of stop signal, must reduce the magnification of first order testing circuit, light intensity is higher so that signal can accurately be detected in writing energy cycle and interval energy cycle.Further, high-frequency modulator is closed in recording process usually, thereby the component of signal that obtains during the low-yield cycle (low light level emission cycle) may be excited the interference of light beam noise and circuit noise, makes that most of component of signals can not be detected in this periodic process.In addition, because the write pulse cycle is very short, detect so in this periodic process, can not carry out stabilization signal.

Yet,, also need to detect such as servosignal and the such signal of swinging signal even during writing down.Servosignal refers to the positional information of track guiding beam spot that is used for along expection, and swinging signal refer to be included on the recording medium such as address information and the such information of rotation information.

Using conventional device for optical information recording to write down in the multistage information process, when laser emitting waveform corresponding to therein can be the time with the interval energy cycle of the light of stablize ratio acquisition q.s, input is possible; Yet in writing energy cycle and low-yield periodic process, because top illustrated, it is impossible that accurate signal detects.In addition, because mark and be with the generation of identical probability at interval, be about half of writing time so be used for cycle effective time of input.Therefore, this will cause the deterioration of the signal quality that detects.

Simultaneously, notice in multi-level recording that wave recording and the control of its time are different with waveform that uses and time control, therefore, can not use conventional laser control circuit (LSI: large scale integrated circuit) in the twin-stage record.In the twin-stage record, information is represented that by the length of mark therefore, the record transmission interval depends on information sequence and changes.For example in CD or DVD,, do not need the interval of the length 3T of waveform processing to be inserted between the mark that needs the complicated wave form processing when minimum mark/gap length is designated as 3T when (T represents the basic cycle).It is the setup time that is used for the transmitted waveform processing of next mark that laser control circuit is handled this gap periods.

On the other hand, in multi-level recording, each all is recorded in the center of a unit mark of different sizes (area), therefore, and the cycle that the recording light emission has rule.But, between the unit, do not provide at interval and waveform processing must be by continuous execution.

In a word, be used for the laser control circuit of twin-stage record and two main difference being used between the laser control circuit of multi-level recording are:

1) location of record mark (irregular/rule)

2) be used for the arrangement (between record mark, insert/not inserting interval) of the waveform processing of record mark as setup time

Therefore, the conventional laser control circuit that is used for the twin-stage record can not be used for multi-level recording, and the laser control circuit of the multi-level recording of must taking measures to be used for improvement.

In addition, there is such problem: in routine techniques, can not correctly detect swinging signal and the servosignal that is suitable for multi-level recording.

Summary of the invention

Therefore, the present invention considers one or more the problems referred to above of the prior art and conceives, and the objective of the invention is to improve the quality of signals that detects in the performance of holding the record in recording process.According to an aspect of the present invention, the conventional low-yield cycle (off power period) is divided into and is used for remaining on the offset energy cycle that mark forms the low-yield cycle of desired or required quick cooling effect and can realize input therein, describedly is set to have different energy by the cycle after cutting apart.

And another object of the present invention is to improve signal detection performance, and improves the control accuracy of the laser beam intensity degree in the multi-level recording.In addition, an object of the present invention is in the performance of holding the record, can export laser beam with the transmitted waveform that is applicable to multi-level recording.

In addition, another object of the present invention is can carry out optimum detection to swinging signal and servosignal in the multistage information process of record that uses write pulse, low pulse (off pulse), spacing pulse (space pulse) and bias pulse.

According to an aspect of the present invention, the invention provides a kind of optical information recording medium, comprising: be divided into the zone of approximately equalised a plurality of unit, on described zone, form and to be the mark of multiple size according to the information that will be recorded; Wherein the frequency of detected swinging signal is no more than 1/10 of unit frequency from the track swing of being carried out.

According to another aspect of the present invention, the invention provides a kind of device for optical information recording, comprise the unit that is suitable for the multistage information of record on optical information recording medium, described medium has the zone that is divided into approximately equalised a plurality of unit, record forms the mark that can be multiple size according to the information that will be recorded on described unit, and wherein the frequency of detected swinging signal is not higher than 1/10 of unit frequency from preformed track swing.

According to another aspect of the present invention, the invention provides a kind of optical information playing device, comprise the unit that is suitable for the multistage information of playback of recorded on optical information recording medium, described medium has the zone that is divided into approximately equalised a plurality of unit, the information that basis is recorded on described unit forms and can be the mark of multiple size, and wherein the frequency of detected swinging signal is not higher than 1/10 of unit frequency from preformed track swing.

According on the other hand, the invention provides a kind of light information recording method that is used for the multistage information of record on optical information recording medium, wherein the zone of optical information recording medium is divided into approximately equalised a plurality of unit, and carried out label record that the laser beam of modulation can form with multiple size by irradiates light intensity on described unit according to the multistage information that will be recorded, described method comprises step:

Thereby illuminating laser beam record mark thereon on described unit, wherein said laser beam comprise have the writing energy cycle, have the low-yield cycle of the light intensity lower of predetermined light intensity than the predetermined light intensity of writing energy cycle, the offset energy cycle that has the interval energy cycle of the light intensity lower but higher and have the light intensity lower but higher than the light intensity in low-yield cycle than the light intensity of interval energy cycle than the light intensity in low-yield cycle than the light intensity of writing energy cycle.

According to a further aspect in the invention, the invention provides a kind of device for optical information recording that is suitable for the multistage information of record on optical information recording medium, wherein the zone of optical information recording medium is divided into approximately equalised a plurality of unit, and carried out label record that the laser beam of modulation can form with multiple size by irradiates light intensity on described unit according to the multistage information that will be recorded, described device comprises:

The unit that be used for it being comprised and have the writing energy cycle, have the low-yield cycle of the light intensity lower of predetermined light intensity, offset energy cycle of having the interval energy cycle of the light intensity lower but higher than the light intensity in low-yield cycle than the light intensity of writing energy cycle and having a light intensity lower but higher than the light intensity in low-yield cycle than the light intensity of interval energy cycle is write down each mark than the predetermined light intensity of writing energy cycle by the setting laser bundle.

According to another aspect of the present invention, the invention provides a kind of device for optical information recording that is suitable for the multistage information of record on optical information recording medium, wherein the zone of optical information recording medium is divided into approximately equalised a plurality of unit, and carried out label record that the laser beam of modulation can form with multiple size by irradiates light intensity on described unit according to the multistage information that will be recorded, described device comprises:

Be used to import the clock signal of expression unit frequency and determine unit for the laser beam transmitted waveform of each unit corresponding to the multistage information of each unit and according to the clock signal of input and multistage information; With

By according to determined laser beam transmitted waveform emission of lasering beam, on each unit, write down multistage information.

According to a further aspect in the invention, the invention provides a kind of laser control circuit that is suitable for the light intensity of emitted laser bundle is modulated for the multistage information of record on optical information recording medium, wherein the zone of optical information recording medium is divided into approximately equalised a plurality of unit, and the label record that can form with multiple size according to the multistage information that will be recorded is on described unit, and described laser control circuit comprises:

Be used to import the clock signal of expression unit frequency and determine laser beam transmitted waveform for each unit corresponding to the multistage information of each unit and according to the clock signal of input and multistage information.

According to another aspect of the present invention, the invention provides a kind of in the wobble signal detection method that is used for multistage information is recorded the multi-level recording on the optical information recording medium, wherein the zone of optical information recording medium is divided into approximately equalised a plurality of unit, and by according to the multistage information illuminating laser beam that will be recorded and the label record that can form with multiple size on described unit, described laser beam comprises the write pulse with predetermined light intensity, low pulse with light intensity lower than the predetermined light intensity of write pulse, spacing pulse with light intensity lower but higher than the light intensity of low pulse than the light intensity of write pulse, with the bias pulse with light intensity lower but higher than the light intensity of low pulse than the light intensity of spacing pulse, described wobble signal detection method comprises step:

Detect push-pull signal from optical information recording medium; With

Eliminate the unit frequency component to extract the swinging signal that expression is formed on the track fluctuation on the optical information recording medium from detected push-pull signal.

According to another aspect of the present invention, the invention provides a kind of device for optical information recording, comprise the control module of controlling according to according to the wobble signal detection method in the multi-level recording of the present invention.

Enter an aspect according to of the present invention, the invention provides a kind of optical information recording medium, comprising:

A zone that is divided into approximately equalised a plurality of unit, mark can form multiple size according to the information that will be recorded on described unit; Wherein

The frequency of detected swinging signal is no more than 1/10 of unit frequency from preformed track swing.

According to another aspect of the present invention, the invention provides a kind of in the servosignal detection method that is used for the multi-level recording of the multistage information of record on optical information recording medium, wherein the zone of optical information recording medium is divided into approximately equalised a plurality of unit, and by according to the multistage information illuminating laser beam that will be recorded and the label record that can form with multiple size on described unit, described laser beam comprises the write pulse with predetermined light intensity, low pulse with light intensity lower than the predetermined light intensity of write pulse, spacing pulse with light intensity lower but higher than the light intensity of low pulse than the light intensity of write pulse, with the bias pulse with light intensity lower but higher than the light intensity of low pulse than the light intensity of spacing pulse, described servosignal detection method comprises step:

Detect the coarse servo signal from optical information recording medium; With

Eliminate corresponding at least a high fdrequency component swinging signal and the unit frequency to extract servosignal from detected coarse servo signal.

According to another aspect of the present invention, the invention provides a kind of optical information recording-playing device, comprise being used for writing down unit with playback information by the position of determining to be irradiated onto the laser beam on the optical information recording medium based on the servosignal that detects by servosignal detection method according to the present invention.

Description of drawings

Fig. 1 is the block scheme of the structure of expression optical disc apparatus according to an embodiment of the invention;

Fig. 2 is the block scheme of the circuit structure of the laser control circuit shown in the hoist pennants 1;

Fig. 3 A-3D is the synoptic diagram that the main points of the multi-level recording operation of carrying out in optical disc apparatus shown in Figure 1 are described;

Fig. 4 A-4D is used for synoptic diagram at the laser emitting waveform of the multi-level recording of optical disc apparatus shown in Figure 1 for expression;

Fig. 5 A-5C is used for producing in bias pulse at optical disc apparatus shown in Figure 1 the oscillogram of the processing of good adjusting for explanation;

Fig. 6 is the curve map of expression laser beam according to the electric current-light intensity characteristic of temperature variation;

Fig. 7 A-7E is for illustrating the synoptic diagram of operating the arrangement of time of high-frequency modulator (HFM) at offset energy in the cycle;

Fig. 8 is the block scheme of another circuit structure of the laser control circuit shown in the hoist pennants 1;

Fig. 9 is the chart of the typical format of strategy (strategy) table that is used for 5 grades of records;

Figure 10 is used for carrying out at multi-level recording the block scheme of the circuit structure of the first wobble signal detection process for expression;

Figure 11 A-11D is the synoptic diagram that the situation of the continuous recording mark that has identical size in multi-level recording is described;

Figure 12 is used for carrying out at multi-level recording the block scheme of the circuit structure of the second wobble signal detection process for expression;

Figure 13 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 3rd wobble signal detection process for expression;

Figure 14 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 4th wobble signal detection process for expression;

Figure 15 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 5th wobble signal detection process for expression;

Figure 16 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 7th wobble signal detection process for expression;

Figure 17 is the curve map of the characteristic of explanation CD according to an embodiment of the invention;

Figure 18 is the block scheme of the circuit structure of (quartered) optical receiver of four minutes of expression;

Figure 19 is used for carrying out at multi-level recording the block scheme of the circuit structure of the first servosignal testing process for expression;

Figure 20 is used for carrying out at multi-level recording the block scheme of the circuit structure of the second servosignal testing process for expression;

Figure 21 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 3rd servosignal testing process for expression;

Figure 22 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 4th servosignal testing process for expression;

Figure 23 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 5th servosignal testing process for expression;

Figure 24 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 7th servosignal testing process for expression;

Figure 25 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 8th servosignal testing process for expression;

Figure 26 A and 26B are the synoptic diagram of the eight servosignal testing process of explanation in multi-level recording.

Embodiment

Below, with preferred embodiments of the invention will now be described with reference to the accompanying drawings.

Fig. 1 is the block scheme of the structure of expression optical disc apparatus according to an embodiment of the invention.

This optical disc apparatus is a device for optical information recording, for example CD driver or DVD driver, and comprise an optical pick-up unit 1 that realizes optical system, drive that optical pick-up unit 1 moves and rotary CD 13 (just, information recording carrier, for example CD or DVD) motor 12, be used to control the motor drive circuit 6 of the rotation of motor 12 and other suitable electronic circuit.

Optical pick-up unit 1 comprise LASER Light Source 2, in known manner will be from the ray guidance of LASER Light Source 2 emitted laser bundles to different element (not shown) optical element, laser beam light is focused to the position of the object lens 3 of a luminous point and control lens so that beam spot is directed into the actuator 4 and the optical receiver (PD: photodiode) 5 of the position of expectation at CD 13.

The various circuit of optical disc apparatus comprise the laser control circuit 7 of basis from the Laser emission of the signal controlling LASER Light Source 2 of scrambler.

Make it comprise that one has writing low-yield cycle that energy cycle, has the light intensity lower than the predetermined light intensity of writing energy cycle, having lowlyer and than the interval energy cycle of the light intensity highland light intensity in low-yield cycle and the offset energy cycle with light intensity lower but higher than the light intensity in low-yield cycle than the light intensity of interval energy cycle than the light intensity of writing energy cycle of predetermined highlight strength by the configuration laser beam, laser control circuit 7 has management, and each is marked at the function of the record on the unit on the zone that is formed on optical recording media.

Fig. 2 is the block scheme of the typical internal circuit structure of expression laser control circuit 7.According to this figure, laser control circuit 7 comprises control module 20, strategy (strategy) generation unit 21 and laser drive unit 22.

The user data as record data that transmits from external source is converted into multistage information at the coding circuit (not shown) by the control of CPU (not shown).Be transmitted to the control module 20 of laser control circuit 7 then by the multistage information of coding circuit acquisition.Other signal for example represents that the clock signal of the unit frequency of the signal of record/broadcast state and expression and multistage information synchronization also has been transmitted to control module 20.

In the example of Fig. 2, signal is supplied with from coding circuit; Yet signal also can be supplied with by other different circuit.For example, play signal/tracer signal can transmit from CPU, and clock signal can transmit from clock generation circuit.

For example, control circuit 20 produces circuit 21 and Laser Drive unit 22 according to the signal Provisioning Policy that receives.

For example, output signal and clock signal according to control module 20, tactful generation unit 21 produces a pulse signal according to the time control of writing energy cycle, low-yield week, offset energy cycle and interval energy cycle, and laser beam is carried out radiation to write energy Pw, low-yield Pof, offset energy Pb and interval energy Ps respectively in described these energy cycle.

Laser Drive unit 22, for example according to postponing play signal/delays tracer signal (obtaining by processing time), writing the pulse signal of energy cycle, low-yield cycle, offset energy cycle and the time control of energy cycle at interval and for the strength signal of each pulse appointment is identified for the drive current of lasing light emitter 2, laser beam is launched to write energy Pw, low-yield Pof, offset energy Pb and interval energy Ps respectively in described these energy cycle from the expression of tactful generation unit 21 to play signal/tracer signal delay policy generation unit 21.

In other words, control module 20, tactful generation unit 21 and Laser Drive unit 22 have such function: the clock signal of input expression unit frequency and the multistage information corresponding with each unit and determine a laser beam transmitted waveform for each unit according to the clock signal and the multistage information of input.

In addition, because there is very big difference in the output characteristics of the current light of lasing light emitter 2 according to temperature, is used to detect output light intensity and makes the stable output control function of output so Laser Drive unit 22 has.Light intensity detects and can be carried out by the optical receiver of installing in the lasing light emitter 25, and is perhaps opposite, and the optical system that is used to detect light intensity can be provided with separately.In addition, Laser Drive unit 22 can have the high frequency overlaying function of the output noise that is used to reduce lasing light emitter 2.

Other circuit comprises I/V (current/voltage) circuit 8, is used for the reflected signal from CD 13 that optical receiver 5 places receive is carried out the conversion of electric current to voltage, and its result is transmitted to some different testing circuits through the signal of conversion.

I/V circuit 8 is corresponding to first order circuit, and here, be respectively play and recording setting suitable conversion efficiency than (gain).

RF testing circuit 9 extracts the multistage information component that is recorded on the CD 13, and detected component is sent to the decoding circuit (not shown).Then, demoder changes multistage information component into user data.

Wobble detection circuit 10 is extracted the swinging signal component that is included in the track that is formed on the CD from expression from the push-pull signal of the difference between the output of each parts of optical receiver 5, the each several part of optical receiver 5 is to be cut apart by the cut-off rule that extends along the track tangential direction on the CD 13, and wobble detection circuit 10 sends to address detection circuit (not shown) and clock detection circuit (not shown) with the component that is extracted, for example, make swinging signal can be used to manage the absolute fix of CD 13, produce and medium rotation clock signal synchronous, rotate with control medium.The time control signal that is suitable for wobble signal detection is mainly provided by laser control circuit 7.

Servo testing circuit 11 extracts the positional information of laser beam points and sends to motor drive circuit 6 and instructs, and motor drive circuit 6 is used for that beam spot exposed to the position of expectation and drives optical pick-up unit 1 and actuator 4 moves.

Fig. 3 A-3D is the synoptic diagram that the main points of the multi-level recording operation of carrying out in the optical disc apparatus of Fig. 1 are described.

As shown in Figure 3A, the imaginary unit with identical in fact (virtually uniform) length is defined within on the track that forms on the CD 13, and forms a record mark in the center of each imaginary unit.As an example, in the figure, the mark of level 3 (L3), level 4 (L4) and level 1 (L1) is recorded in respectively on three continuous imaginary units.In Fig. 3 B, show the typical shape of record mark.

Fig. 3 C represents to be used for the example of the laser emitting waveform of record mark.Laser emitting waveform comprise with write energy Pw radiation write energy cycle, with the low-yield cycle of low-yield Pof irradiation, with the offset energy cycle of offset energy Pb irradiation and the interval energy cycle of carrying out radiation with interval energy Ps.

Fig. 3 D is illustrated in during the broadcast example of the play signal that obtains from the reflected light of each unit.By judge the level of signal strength of play signal, can estimate the area that is recorded in the mark on each unit and according to the area of each unit can playback of recorded information.

For example, if having three different record marks of three different area (L1-L3) can be recorded on the imaginary unit and can reset, this means the information (that is, not having mark, label L 1, label L 2 and label L 3) that in each unit, to store four level or two bits.On the other hand, if can identify seven different record marks (L1-L7), in each unit, can store the information of eight level or three bits so.

Fixing relation between the area by setting up record mark in the zone that does not exceed optical resolution and the amplitude of play signal can realize multistage information record.

Along with element length shortens,, then more and more be difficult to differentiate the level that is recorded in the multistage information on the imaginary unit because the difference between each level becomes more and more littler.

On the contrary, when element length is increased to the degree that has exceeded optical resolution, signal amplitude will be saturated and therefore can not differentiate multistage information.Because top explanation need or be necessary to take some to limit the relation that is provided with between spot diameter and the element length (cell width).

In addition, notice that imaginary unit needn't the mode with absolute equal length define on whole medium.On the contrary, the variation of a little can take place in the length of imaginary unit, as long as the length that changes can make multistage information present in the scope of suitable difference.

Therefore, for example, cut apart diametrically forming some districts and to use in each district under the situation with the CAV form of mounting medium rotational angular velocity at the posting field of CD 13, element length moves towards the neighboring in each district along with the unit and elongated gradually.Yet by increasing the quantity in district, the difference between the element length of the element length of inner periphery side and the periphery avris in this district can be minimized and can accurately identify multistage information.

Fig. 4 A-4D is used for writing down at optical disc apparatus shown in Figure 1 the synoptic diagram of the laser emitting waveform of multistage information for expression.

In this example, the laser beam transmitted waveform that is used for record mark on imaginary unit can be with four level (L1-L4) recorded information.As shown in the figure, each laser emitting waveform that is used for record mark comprises to be set to the energy cycle of writing of writing energy Pw radiation of the highlight strength that can represent information, to be set at the low-yield cycle of the energy Pof irradiation lower than the light intensity of writing energy Pw, after the low-yield cycle output and with offset energy cycle of the offset energy Pb irradiation that is set at the light intensity lower but higher than low-yield Pof than interval energy Ps, with can separate information and to be set at the interval energy cycle of carrying out radiation than the interval energy Ps that writes the low but higher light intensity of energy Pw than low-yield Pof.Yet, note being used for not comprising the offset energy cycle at the laser emitting waveform of level L1 place record mark.

Be noted that simultaneously that in the accompanying drawings the ellipse figure of filling with hacures is the imaginary unit of the location of the relative unit of expression record mark; Therefore, these figures are not represented the true form of record mark.

When record mark, the launch time of writing energy cycle, low-yield cycle and offset energy cycle according to the level of mark by center skew, so that form mark in the center of imaginary unit from imaginary unit.

Below, will be presented in the processing of carrying out in the optical disc apparatus according to an embodiment of the invention.

With label record to the unit the time, laser control circuit 7 radiation have the laser beam of writing energy Pw, write energy Pw and are set to have predetermined high light intensity in writing energy cycle.For example, the light intensity illuminating laser beam that laser control circuit 7 can 14mW is so that the fusing of the recording layer of CD.Then, in the low-yield cycle, irradiation has the laser beam of low-yield Pof, and low-yield Pof is set to have than writing the low light intensity of energy Pw.In this cycle, light is launched very faint and is not almost launched any light.For example, can be with the light intensity laser beam radiation of 0-0.5mW, so that the recording layer of CD is cooled off fast.Thereby, formed the forward position of mark.

In the optical disc apparatus of routine, up to forming desired mark lengths, radiation has the laser beam corresponding to the interval energy cycle of the light intensity that can wipe mark then corresponding to the laser beam in low-yield cycle in radiation.For example, light intensity laser beam radiation that can 7mW in the energy cycle of interval is to form the back edge of record mark.

Yet, in the present embodiment, after the low-yield cycle, providing the offset energy cycle, the laser beam that has offset energy Pb in this cycle is set to and has the light intensity lower but higher than low-yield Pof than interval energy Ps (that is Ps＞Pb＞Pof).For example, can use the laser beam of light intensity with 1-2mW for the offset energy cycle.

Corresponding to the light intensity Pb of the laser beam in offset energy cycle preferably in such level range: component of signal can protectedly be avoided the interference at the noise of the first order circuit gain that is used for writing down (it is lower than the gain that is used to play) in this scope, the characteristic of can holding the record simultaneously.Therefore, be cooled during recording layer low-yield after writing energy cycle, forming mark, even and during the offset energy cycle radiation have a laser beam of the high light intensity of proportion exoergic Pr, mark also can not wear out (degraded).In addition, notice that the specific light intensity value that provides in the superincumbent explanation only is an example, and these values can change according to the layer characteristic of medium.

In the laser beam transmitted waveform of the optical disc apparatus of routine, when the short mark of continuous formation, signal can detect in the energy cycle process of interval, and can obtain the recording quality that meets the demands.Yet, when the long mark of continuous formation, the mark of locating at level 4 (L4) for example, can not carry out betwixt input write energy cycle and the low-yield cycle has taken the major part of bombardment with laser beams time, and the interval energy cycle that can carry out input betwixt is very short so that recording quality has descended.

Yet, according to present embodiment, can during the offset energy cycle, extract component of signal, even make that forming long mark continuously can not reduce recording quality yet.Simultaneously, according to top recording processing, the offset energy cycle was inserted in after the low-yield cycle; Yet the arrangement of time in offset energy cycle is not limited to such layout, but the offset energy cycle can be inserted into any moment of the bombardment with laser beams periodic process that is used for record mark.

By insert offset energy part in the laser beam transmitted waveform that is used for mark formation with the light intensity between the light intensity of low-yield part and interval energy part, can prevent the decline of recording quality, even between the long mark phase of continuous recording, also can detect different detection signals, and can make the output control stabilizationization of laser beam.

Below, will be presented in the further processing of carrying out in the optical disc apparatus of present embodiment.

In order on CD, accurately to form record mark, can be each record and be adjusted in the laser beam launch time of offset energy in the cycle with correct size.

Described " with correct accurate in size formation record mark " is not to mean that the physical area of record mark must be corresponding to multistage value (level of multistage information), but the record area can easily be identified the multistage information of record in play signal.

In multistage information record, owing to formed the mark littler than optical resolution, so it is normally fixing to be used for the initial information of the record mark needed time width of writing energy cycle, and irrelevant with multistage information.Therefore, be used for definite principal element of the marked region of multistage information of representing and be " time width in the time width in low-yield cycle+offset energy cycle ".

The time width that is used to cool off the needed low-yield cycle of recording layer of CD for every group of multistage information is to determine by the characteristic of recording layer, and therefore fixes, and irrelevant with multistage information.

In the present embodiment, by the time width that the offset energy cycle is set make its time portion that matches corresponding to level (multistage value) with the multistage information that is recorded and the time portion that is conditioned according to every group of multistage information and, laser control circuit 7 is regulated the time width in the offset energy cycle that is used for every group of multistage information.

The processing of regulating the time width in offset energy cycle according to every group of multistage information that is recorded depends on such fact: be formed with the mark of the distribution of the area with " multistage value-1 " on each unit, make the time width in offset energy cycle match with the level of the multistage information that is recorded is approximate.

Fig. 5 A-5C is the synoptic diagram of explanation processing of the time width in adjusting offset energy cycle in the optical disc apparatus of present embodiment.

Fig. 5 A illustrates the waveform (clock signal) of the unit clock of expression unit frequency; And Fig. 5 B illustrates the waveform of the n times of clock signal (n is an integer) in the cycle with n unit clock frequency doubly.Shown in Fig. 5 C, the level of bias pulse time according to the multistage information that is recorded is that unit changes pro rata with time width Tx.Promptly, the time width in offset energy cycle that is used for record mark L2 is than the long-time width Tx of the time width in the offset energy cycle that is used for record mark L1, and the time width in offset energy cycle that is used for record mark L3 is than the long 2Tx of time width (twice of time width Tx) in the offset energy cycle that is used for record mark L1.

Yet the recording layer of optical recording media needn't have linear characteristic, and is used to needed time of play signal level of obtaining to expect and changes according to the multistage value of aforesaid and afterwards unit.Therefore, in the time width Ty that the multistage information for every grade provides, preferably the time width in offset energy cycle is finely tuned, shown in Fig. 5 C.Laser control circuit 7 passes through according to calculating formula: Tb=(a-1) Tx+Ty (Tb: the time width in offset energy cycle; A: multistage value) finely tune to determine the time width in offset energy cycle.

Therefore, the time width that is used for the offset energy period T b of level 1 is Ty, the time width that is used for the offset energy period T b of level 2 is " Tx+Ty ", the time width of offset energy period T that is used for level 3 is for " 2Tx+Ty ", and the time width that is used for the offset energy period T b of level 4 is " 3Tx+Ty ".

Note, in regulating the time width in offset energy cycle, use under the situation of the time portion that the level with multistage information matches, be used for determining with regard to minimum optical resolution, must considering whole unit in management for the parameter of the time width in offset energy cycle of multistage information.On the other hand, under the situation that adds/deduct the time width unit that matches with multistage value, manage according to the multistage value of the information that is recorded and corresponding well-tuned part rather than whole unit parameter, thereby can significantly reduce the processing load of laser control circuit 7 time width that is used for determining the offset energy cycle.

According to this embodiment, because the time width in offset energy cycle partly is made up of the level (multistage value) according to multistage information proportional time portion that is coupled with/deducts and the well-tuned that is used for each record, so, can simplify the setting of pulse width and the time control of each energy part.

Below, introduce an alternative embodiment of the invention, wherein laser control circuit 7 output offset energy cycle when multistage information satisfies predetermined condition.

Shown in Fig. 4 A, when forming mark by radiation corresponding to the laser beam of writing energy cycle and low-yield cycle at the minimum required time cycle, that is, when forming label L 1, non-radiating is used for the laser beam in offset energy cycle.Simultaneously, when recorded information was the L0 in expression space (not having mark), laser emitting waveform was made up of the interval energy cycle, and did not therefore produce the laser beam that is used for the offset energy cycle.In addition, be very short (for example, label L 2) so that can not detect effectively under the situation of component of signal in the offset energy cycle, can preferably eliminate the laser beam emission that is used for the offset energy cycle.

Make the deterioration that such being provided with prevents the component of signal that the response speed owing to restriction in the optical receiver and circuit causes, and being used to eliminate the influence of not expecting from noise, described noise produces when during the short period component of signal being taken a sample.

Therefore, when multistage information satisfies certain conditions, be used for the laser beam in offset energy cycle, in the time can't guaranteeing the grace time width of accurate input, can prevent to be used for the laser beam emission in offset energy cycle by output.As a result, in the offset energy periodic process, can eliminate the error that in input, exists and can detect high-quality signal.

Below, introduce an alternative embodiment of the invention, wherein the laser control circuit 7 control light intensity (Pb) that is used for the laser beam in offset energy cycle makes it be higher than light intensity (Pr) in the laser beam of the multistage information process radiation of resetting.

Offset energy Pb preferably is set to the maximum level in level range, in described scope, can access enough recording qualities for input.Playback energy Pr is set to such level: even this moment, replay operations was carried out a long time, also can prevent the data aging that writes down.For example, can be set to 0.7mW by the playback energy.In other words, the playback energy be preferably set to be lower than recording layer can be by the level of heat ageing, but the comparable playback energy of offset energy Pb Pr height because the offset energy cycle in recording process, show as the short period.

In addition, be lower than playback energy Pr, and first order circuit gain may be difficult to the signal quality that obtains to expect than when playback time low when offset energy Pb is set to.

Therefore, preferably be set to the high light intensity of proportion exoergic Pr, so that can obtain expected effect from the offset energy cycle corresponding to the light intensity Pb of offset energy Pb.

Offset energy Pb by the offset energy cycle is set to be higher than the light intensity in playing process, and the optimal circuit gain that promptly is used in record is low, can prevent that also the signal that detects during the offset energy cycle is subjected to the interference of noise.

Below, will introduce further embodiment of the present invention, but in particular for the rewriting type medium, phase change medium for example, wherein laser control circuit 7 at interval the light intensity of energy cycle be set to wipe the level of mark.

But in the rewriting type medium, the low-yield cycle of low light intensity with laser beam transmitted waveform of the record mark of being used to form is extended, and simultaneously, but the reflectivity of rewriting type medium is low, makes and can not carry out input in the low-yield cycle.Yet,, can improve signal detection performance in the laser beam transmitted waveform by the offset energy cycle is set according to the present invention.

Therefore, according to present embodiment, but even make the detection of component of signal very use the rewriting type medium under the situation of difficult, the signal detection performance that during the offset energy cycle, also can be improved in the antiradar reflectivity and the low light intensity in low-yield cycle owing to medium.

Below, to introduce further embodiment of the present invention, wherein laser control circuit 7 detect be used for the offset energy cycle and at interval the laser beam of energy cycle light intensity and according to this detect the light intensity compensation be used to write the light intensity of energy cycle so that keep the precision of the output intensity of laser beam.

Fig. 6 is the curve map of expression laser beam according to the electric current-light intensity characteristic of temperature variation.

There is very big difference in the output characteristics of laser beam according to temperature.As shown in the figure, the light intensity remolding sensitivity that when temperature (T) is 50 ℃, changes low when temperature is 25 ℃ with current value (amount of electric current).

Therefore, for example, locate for 25 ℃ in temperature, when being set to, can export when being used for the current value I s of the light intensity of the interval energy Ps of energy cycle at interval drive current, it is about 2/3 that the output light intensity Ps that locates 50 ℃ of temperature is reduced to, as what represented by circlec method on T=50 ℃ dotted line among the figure.Therefore, make light intensity by constant remaining on the identical level, can obtain corresponding current value I s ', as represented by square on 50 ℃ dotted line for 50 ℃ by interval energy Ps and the Control current value that detects outgoing laser beam.

Yet control is unusual difficulty corresponding to the light intensity of writing energy Pw that is used to write energy cycle.This is because it is short writing the width of writing the energy part of energy Pw, therefore is difficult to accurately detect light intensity.

For example, as interval energy Ps and the difference between current (Iw-Is) when writing energy Pw 25 ℃ of temperature be added to current value I s ' (Is '+Iw-Is) time, the current value I w that the result obtains " locates can not export 50 ℃ of temperature and writes energy Pw; opposite output is lower writes energy Pw ", as being marked by triangle △ on 50 ℃ the dotted line, this effect is the result who there are differences in sensitivity.

Therefore, preferably, the light intensity of another energy part is detected in order to obtain light intensity sensitivity, and the current value that uses the Calculation of Sensitivity according to this acquisition to obtain.In optical disc apparatus according to the present invention, used the light intensity in offset energy cycle.

Specifically, laser control circuit 7 is carried out following calculation process.

At first, carrying out Current Control so that when energy Ps remains on a fixing level at interval, the offset energy Pb in detection offset energy cycle and the current value I b ' in the time of 50 ℃ correspondingly.Then, according to interval energy Ps and corresponding current value I s ', offset energy Pb and its corresponding current value I b ', meter sensitivity (Is '-Ib ')/(Ps-Pb), and be used as the drive current that power P w is write in output from the current value I w ' of equation Iw '=Is '+(Pw-Ps) * (Is '-Ib ')/(Ps-Pb) obtain.

In the optical disc apparatus of routine, except the energy cycle of interval, there is not suitable energy partly to can be used for detecting light intensity, though and to detect for light intensity be sufficiently long the low-yield cycle, the light intensity of this energy part is that low-down making can not guarantee accurate detection.

Therefore, write energy Pw if used low-yield Pof to calculate in above-mentioned computing, current value is minimized with respect to the difference that temperature variation exists so, as shown in the figure, makes can produce error at an easy rate in change of sensitivity detects.In other words, light intensity is high more, and easy more detected temperatures changes, and impossible more generation error.

Yet, according to present embodiment, because the offset energy cycle is provided for the multistage information of record, so can carry out laser beam control, at this moment, be used at interval by detection that energy cycle and the laser beam intensity degree in offset energy cycle can obtain sensitivity, and detect according to sensitivity and to be used to be unsuitable for the energy part that light intensity detects, that is, write the current value of energy cycle.

Under the situation of not using above-mentioned computing, record is periodically suspended leaving from posting field, and detects and compensate the electric current-light characteristic of each energy part.

Therefore, be used for the energy cycle and the laser beam intensity in offset energy cycle at interval by detection, and according to the light intensity of this detection energy cycle is write in compensation, when in the label record process because variation of temperature when the variation of laser characteristics has taken place, the information recording processing needn't be suspended to correct the Laser emission characteristic.Therefore, the light intensity of each energy part is maintained at optimum level, makes it possible to obtain high recording quality.

Below, will introduce further embodiment of the present invention, wherein in the cycle high-frequency modulator is operated at offset energy.

In by the multistage information process of laser beam emission record, owing to influence, in laser beam output, produced instability, and instability is especially obvious in low output from back light (reflected light).In order to resist this influence, used high-frequency modulator (FHM).In the process of playing with low output, use high-frequency modulator to export with stable, and this modulator can be unlocked/cut out with the high-frequency emission laser beam.

Usually, the laser beam in recording process is output as height, and therefore, can not use the high-frequency modulator that is used to eliminate from the influence of back light.

Yet, under the situation of multi-level recording, during writing down,, thereby produce the problem of the instability output of laser beam in the detected signal components in the cycle of the offset energy with low output.Therefore, had better be in the offset energy periodic process priority service high-frequency modulator so that the laser beam output stabilization.

According to present embodiment, laser control circuit 7 control high-frequency modulators are to operate in the offset energy periodic process.

Fig. 7 A-7E is for illustrating the synoptic diagram of operating the arrangement of time of high-frequency modulator (HFM) at offset energy in the cycle.

Fig. 7 A represents imaginary unit (the mark * among the figure represents digital 1-4); Fig. 7 B represents virtual record mark (with the mark that is recorded); Fig. 7 C is illustrated in the energy waveform in broadcast and the recording process; Laser beam transmitted waveform when Fig. 7 D is illustrated in the offset energy periodic process high-frequency modulator operated; And Fig. 7 E represents to be used to operate the waveform of the open/close time control signal of high-frequency modulator.

According to the time control signal shown in Fig. 7 E, laser control circuit 7 control high-frequency modulators are operated in the offset energy periodic process.

By in the offset energy periodic process, operating high-frequency modulator, in the light intensity level is low offset energy periodic process, can make the laser beam output stabilization, and can realize that high-quality signal detects.The attention high-frequency modulator also can be operated in the energy cycle of interval.

Below, further embodiment of the present invention will be described, represent that wherein the table of the predetermined relationship between multistage information and the laser beam transmitted waveform is performed.

Fig. 8 is the block scheme through the circuit structure of improved laser control circuit.

By replacing laser control circuit 7 shown in Figure 1 with this circuit structure, be transfused to control module 20 with the clock signal of the unit frequency of multistage information synchronization and the multistage information that will be recorded on each unit, and with reference to having stored the table 23 (strategy) of the predetermined relationship between multistage information and the laser beam transmitted waveform to be identified for the suitable strategy of each unit.The strategy that is used for each unit comprises the width and the arrangement of time of each energy part.

For each unit, the data of finding from table 23 are sent to tactful generation unit 21 and produce gating pulse corresponding to the laser emitting waveform of determining of this unit (write energy cycle, low-yield cycle, offset energy cycle and control signal launch time of the laser beam emission of energy cycle) at interval.Then gating pulse is sent to laser drive unit 22, it is managed the laser beam that is launched by each light intensity of writing energy Pw, low-yield Pof, offset energy Pb and interval energy Ps.

Here, it should be noted that and not use table 23 to realize the setting of the strategy of each unit, in this case, use the function (function) of multistage information to determine each energy width partly.And, if being transfused to control module 20 and high-frequency modulator function, play signal/tracer signal is implemented in the laser controlling unit 22, then in broadcast and offset energy periodic process, can realize the filtering operation of high-frequency modulator.

Therefore, by input expression unit frequency and the clock signal that will be recorded in the multistage information on each unit to be identified for the laser beam transmitted waveform of each unit, can accurately form record mark in the center of unit, this recording method is the characteristic of multi-level recording.

In addition, by be identified for the laser emitting waveform of each unit with reference to the table that comprises the predetermined relation between multistage information and the transmitted waveform, and according to the laser emitting waveform drive laser beam emission of determining, according to the distinctive multi-level recording method of the center formation record mark that can be implemented in the unit for the waveform width of every group record information adjustment and arrangement of time.

Simultaneously, described table seat number comprises and is used for the information of determining the laser beam transmitted waveform at least corresponding to the multistage information of three continuous unit according to one group.According to this embodiment, described table comprises such information: be used to use the multistage information of the multistage information of the current unit that writes down and a previous element and a back unit that the information of transmitted waveform is set as parameter.

Fig. 9 is the typical format of the table (Policy Table) in 5 grades of records.

In this table, multistage information for the current unit that will write down is represented as " active cell ", multistage information for the unit before the active cell is represented as " at front unit (precedingcell) " (this unit has had the information of record thereon), and is represented as " unit subsequently (subsequent cell) " (this unit will write down) immediately following the multistage information of the unit after the active cell after the record of active cell.The level of each unit is designed to a matrix, and stores time value of setting of each gating pulse.

(a, b c:0-4) represent time value of setting of each gating pulse to value Tabc shown in the table.Here, " a " is illustrated in the multistage information of front unit, the multistage information of " b " expression active cell, and the multistage information of " c " expression unit subsequently.Though in table shown in Figure 9, the time value of setting of respectively organizing multistage information and the above-mentioned value that are used to comprise the unit formerly of level 2 have been omitted, the table of Shi Yonging has been stored the transmitted waveform parameter that is used for all level in the present embodiment.

In addition, with reference to table shown in Figure 9, have only parameter (time width or the well-tuned part that for example, are used for a offset energy cycle) energy that is used for gating pulse designated; Yet, for example, also can be provided for specifying similar table such as other parameter of the time width of write pulse and/or low pulse.

By come width information and/or time control information storage time at least according to the combination of the multistage information that is used for three continuous unit in the table, and with reference to the definite laser beam transmitted waveform of this table, multistage information can be recorded the signal Recombinant Interferon that makes from the mark of adjacent cells in such a way and be limited in a known characteristic range, and when resetting the medium of this record, can be eliminated, thereby can improve broadcast performance and obtain higher density.

In addition, the high frequency clock cycle that produces according to the clock signal of unit frequency be preferably used for being provided with at tactful generation unit 21 places the minimum resolution of gating pulse width and time control.In other words, the frequency of the clock signal by will representing unit frequency cycle of multiply by the frequency that n (n is an integer) obtains is used as the step-length (step) that the laser beam transmitted waveform is set.

In circuit structure shown in Figure 8, the clock signal of unit frequency is transfused to PLL circuit 24, and herein, the frequency of this clock signal is multiplied by n (n is an integer) to produce n times of clock signal.N clock signal doubly is exported to tactful generation unit 21 then.

At tactful generation unit 21 places, the cycle of n times of clock signal is used to gate time and pulse width according to the value of setting that obtains from table 23, thereby produces gating pulse.

Use the cycle of n times of clock signal to come his-and-hers watches 23 to be provided with as step-length (step).

Therefore, clock signal by the arrangement unit frequency is so that its velocity variations with medium is consistent, then the width of the gating pulse that produces at tactful generation unit 21 places also can correspondingly be changed, and makes each record mark to be recorded with desired size, even the speed of medium changes.

In addition, it should be noted that and to use analog delay element to change pulse width and arrangement of time; Yet this is not an extraordinary result, changes because can be used as the result of temperature variation time delay.And, writing speed according to medium radial location continually varying CAV method in, when analog delay element is used to change pulse width and arrangement of time, increased the quantity of analog delay element, thereby increased circuit size; Yet in the cycle of the clock signal of the n frequency multiplication by using the expression unit frequency, circuit size can be reduced.

Therefore, (n: integer) cycle of the clock signal of frequency multiplication is provided with laser emitting waveform as step-length (step) by using the n that represents unit frequency, even when the medium rotational speed changes, also can keep the consistance of label size, thereby can guarantee the high level signal quality.And, not resembling analog delay element, present embodiment does not have the shortcoming that is tending towards temperature variation, even be can realize little circuit in the continually varying CAV method in writing speed therefore yet.

Even the optical disc apparatus according to present embodiment also can be with the different signal of high quality detection in recording process.And this device can accurately be controlled the light intensity of laser beam and can regulate wave recording to realize high recording quality according to recorded information.

In addition, (can rewrite: RW) medium is very favorable for the inversion of phases that wherein uses erasable energy as the interval energy in the energy cycle of interval in the present invention; Yet confers similar advantages can also realize in other optical information recording medium, for example uses therein with low light intensity (recordable: R) as the write-once type medium of the waveform of interval energy cycle (because erasable be unnecessary).And, though note in the above embodiment of the present invention, by arranging each to write energy cycle and the low-yield cycle forms record mark, but the present invention is not limited to such arrangement, and for example, to such an extent as to be set under the oversize situation that in input, has occurred worsening in the low-yield cycle and can produce adjusting.

In light information recording method according to the present invention and device for optical information recording, the low-yield cycle of laser beam emission is divided into the offset energy cycle that has the low-yield cycle that is used for the required quick cooling effect of label information and can carry out input, and by partly change the light intensity of laser beam according to each energy, the quality of signals that detects in recording process can be enhanced, and can keep the performance of multistage information record simultaneously.

And, by the problem of solution, in the light intensity of control laser beam, can realize bigger precision as the low signal detection performance of the exemplary shortcomings of the waveform that is used for multi-level recording.In addition, when keeping performance, can realize having the output of the laser beam of the transmitted waveform that is suitable for multi-level recording.

Below, introduce the typical wobble signal detection process in multi-level recording according to the preferred embodiment of the invention.

Figure 10 is used for realizing at multi-level recording according to an embodiment of the invention the block scheme of the circuit structure of the first wobble signal detection process for expression.

Figure 11 A-11D is the synoptic diagram of explanation in multistage information recording method according to the present invention situation of the consistent mark of continuous recording on each unit.

In order to realize the first wobble signal detection process, wobble detection circuit 10 shown in Figure 1 is arranged to and comprises wave filter 120 and gain control (GC) circuit 121, as shown in figure 10.

Here, the optical disc apparatus of Fig. 1 has such function: it comprised have the predetermined high-intensity low pulse of writing energy pulse, having the light intensity lower than the light intensity of write pulse, have light intensity than write pulse by the recording laser bundle is set low but than the high spacing pulse of the light intensity of low pulse with have the offset energy pulse lower but higher than the light intensity of low pulse than the light intensity of spacing pulse, can write down each mark on each unit that forms on the zone of optical recording media.And wave filter 120 has the function of eliminating the unit frequency component from the push-pull signal that detects from optical recording media.And GC circuit 121 has from by eliminate the function that signal extraction that the unit frequency component obtains is illustrated in the swinging signal of the track swing that optical information recording medium forms from push-pull signal.

Be similar to tracking signal, the swinging signal that is illustrated in the swing of the track that forms on the CD 13 can obtain from push-pull signal (difference signal of the difference between the output of the various piece of expression optical receiver 5, optical receiver 5 is divided into two parts by the cut-off rule that extends along the direction of track tangential direction).

Because the swinging signal frequency ratio is followed the tracks of the frequency range height of swing, so also can be detected even in the swinging operation process, also remain with swinging signal.

Yet in recording process, the intensity of laser output is modulated, so the detection of swinging signal is difficult.

Especially, by there not being the recording laser bundle emission of bias pulse, when the big mark of continuous recording one by one, can not guarantee sense cycle effectively.On the other hand, by the Laser emission that comprises bias pulse that is used to write down, in the bias pulse periodic process, effective detection of swinging signal is possible.

Because push-pull signal is difference signal, so desirable laser intensity modulation product has been removed, so the changes in amplitude of swinging signal component is accurately detected.

Yet, in fact, for example, can occur in the axle of lens and ray variation or because the inclination of medium and the Strength Changes that between the optical receiver part of cutting apart, exists, therefore, the intensity modulated component of laser can be by superposition on push-pull signal, thereby causes the deterioration of swinging signal.

Below, introduce top problem in detail with reference to Figure 11 A-11D.

On the imaginary unit shown in Figure 11 A, can form record mark with different size.Yet, below, will introduce as simplified embodiment and to form continuously the situation of record mark of size that has for half of the element length of the imaginary unit shown in Figure 11 B.Figure 11 C illustrates the laser emitting waveform that is used for record mark.

Use a plurality of smooth emissive porwers to come laser emitting waveform is modulated.Because " error (corruption) " appearred in the limitation that exists aspect the transport property of optical receiver and/or circuit in reflected signal in the recording process shown in Figure 11 D.In the waveform shown in Figure 11 D, moving more between spacing pulse and the bias pulse (transition) is tangible.

In this case, the frequency of this reflected signal is identical with the frequency of unit.When having occurred intensity difference owing to certain fluctuation in divided optical receiver, thereby the above-mentioned reflected signal that is used for writing down is retained in the noise that push-pull signal becomes the swinging signal component.

In other words, in multi-level recording, the unit frequency component tends to by strong superposition, and therefore, at the circuit structure that is used for carrying out the first wobble signal detection process, wave filter 120 is inserted into to eliminate the unit frequency component in multi-level recording.

And according to the form of CD (recording medium) 13, the swinging signal of the rotational speed that is used for control medium that obtains from the track of medium may be applied and become noise.In this case, these components also are removed.

In addition, in the system for the high-speed record assembling, also by write pulse and low pulse influence, the filtering characteristic that therefore can eliminate the frequency component higher than unit frequency is preferred to reflected light.Just, wave filter is preferably the low-pass filter that is used to remove the frequency component on unit frequency.And GC circuit 121 is implemented to carry out gain compensation according to the output of wave filter 120 and makes that the amplitude of swinging signal is suitably regulated.

By this way, the deterioration that the unit frequency component is eliminated the swinging signal that makes that the Laser emission of the strong unit frequency be used for multi-level recording causes is prevented from, and can detect high-quality swinging signal.

Then, with the second wobble signal detection process that is presented in the multi-level recording.

Figure 12 is used for carrying out at multi-level recording the block scheme of the circuit structure of the second wobble signal detection process for expression.

Be to detect the swinging signal of a certain signal quality level with simple circuit configuration in the circuit structure of the second wobble signal detection process of carrying out in the multi-level recording.

Usually, write and Laser emission intensity optimization can be made and can write down the multistage information of high-quality by before user data, testing.Here, preferably the optimum gain of swinging signal changes along with the variation of the light intensity of laser beam.

The circuit structure that is used to the second wobble signal detection process of carrying out shown in Figure 12 comprises wave filter 120 and as gain control (GC) circuit 121 of laser control circuit shown in Figure 17 and wobble detection circuit 10.

Specifically, GC circuit 121 comprises laser control circuit 7, CPU 130, D/A transducer 131 and VCA 132.

In other words, GC circuit 121 shown in Figure 12 has such function: use according to the light intensity of the light intensity of the bias pulse that is used for determining gain and spacing pulse calculate at least one value of setting extract swinging signal, described gain is applied to by eliminate the signal of unit frequency component acquisition from push-pull signal.

In GC circuit 121, manage the light intensity of Laser emission by CPU 130; Just, CPU130 is provided with the optimal light intensity level to laser control circuit 7.Selectively, can itself be provided with to read the setting of electric current light intensity laser control circuit 7.

According to the light intensity setting, CPU 130 calculates the average laser emission measure by the empty filtering acquisition of light intensity modulation component, and D/A transducer 131 is provided with suitable value to determine the gain of VCA 132.

The gain of VCA 132 changes according to the output voltage of D/A transducer 131.Can obtain the average laser emission measure according to generation rate by pulse width, light intensity and the multistage information of each pulse of CPU management.

Therefore, gain becomes optimum value so that just can guarantee recording quality by simple circuit structure corresponding to the continuous variation of recording light intensity, and realizes best wobble signal detection process.

Below, with the 3rd wobble signal detection process that is presented in the multi-level recording.

Figure 13 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 3rd wobble signal detection process for expression.

This circuit structure is used for realizing the stable oscillation testing process with the mean variation at recording process reflected signal (and signal).

Because the variation of the reflectivity of dielectric surface or medium track, perhaps the fluctuation of laser intensity and signal change (modulation product of each pulse of frequency ratio is low) at the low frequency place.In addition and signal change according to the continuity of multistage information.These fluctuations in broad frequency range can influence swinging signal as the factor of the gain that is used to change it.

Therefore, by in multi-level recording, carrying out the circuit that is used to carry out the 3rd wobble signal detection process, can prevent above-mentioned problem.

Circuit structure shown in Figure 13 comprises wave filter 120 and as gain control (GC) circuit 121 ' of wobble detection circuit shown in Figure 1 10.

GC circuit 121 ' comprises VCA 140, wave filter 141, VCA 142, amplitude detection circuit 143 and comparer 144.

In other words, GC circuit 121 ' shown in Figure 13 has the function of extracting swinging signal by amplification or attenuated signal, and described signal is by using with the gain that is used for equating by the gain that remains on a predetermined reference voltage from the signal level with the acquisition of signal elimination hunting frequency component, the unit frequency component being removed acquisition from push-pull signal.

In this circuit, the hunting frequency component, and is exaggerated or weakens at voltage gain control amplifier (VCA) 142 from the output signal of wave filter 141 by from removing with signal at wave filter 141 places.Then, detected at amplitude detection circuit 143 places from the amplitude of the output signal of VCA 142, and compare at comparer 144 places and predetermined reference voltage signal from the output signal of VCA 142.Then, be exported to VCA 142 so that change in gain corresponding to voltage by the difference that relatively obtains.

By this loop, the gain Be Controlled of VCA 142 makes the amplitude output signal of VCA 142 reach predetermined reference voltage.As for push-pull signal, the high fdrequency component at the frequency place on unit frequency is removed at wave filter 120 ', and filtering signal is exaggerated by VCA 140 or weakens afterwards.Here, the gain of in VCA140, using with VCA 142 is provided with the gain equate.

Therefore, fluctuation of reflectivity by the medium track of response in multi-level recording recording of information process or Laser emission strength fluctuation continuously change gain so that gain optimization can realize best wobble signal detection in the mode of loop cycle.

To be presented in the 4th wobble signal detection process in the multi-level recording below.

Figure 14 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 4th wobble signal detection process for expression.Note being presented identical numeric character with the corresponding part of part shown in Figure 13.

This circuit structure is closely similar with the circuit structure that is used to the 3rd wobble signal detection process of carrying out in multi-level recording; Yet, circuit structure among Figure 14 comprised also that before wave filter 141 sampling keeps (S/H) circuit 145, and the sampled signal that the sampling process by bias pulse cycle or spacing pulse cycle obtains is used as baseband signal, and does not use the mean value with signal.

Therefore, GC circuit 121 shown in Figure 14 " by amplifying or attenuated signal has the function of extracting swinging signal, described signal is by using and being used for and will remaining on gain that the gain of a predetermined reference voltage equates, the unit frequency component is removed acquisition from push-pull signal with level signal in that the Laser emission periodic process of Laser emission cycle of bias pulse or spacing pulse is that obtain.

Because it is basic identical with the circuit structure that is used to the 3rd wobble signal detection process of carrying out to be used for the circuit structure of the 4th wobble signal detection process of carrying out at multi-level recording, to introduce the different feature of the latter's structure so, that is, S/H circuit 145 and the signal that inputs to wave filter 141.

As previously described and signal comprise the successional fluctuation that relates to multistage information. for example, when the multistage information of ten continuous unit is: " 0,0,0,0,0,4,4,4,4,4 " then comprise the fluctuation of the frequency component with 1/10 unit frequency with signal.In general, in order to separate hunting frequency, modulating mode is controlled in the stage of multistage modulation, and fluctuation feasible and signal is prevented near the swinging signal frequency.After increasing quantity of information by the additional redundancy position, modulating mode control comprises the use of eliminating special pattern.

This means that conversely recording density has been reduced, and the advantage that therefore obtains higher density in the multi-level recording method has been lowered.In addition, do not resemble the twin-stage record, in multi-level recording, be difficult the separating fully of frequency of realizing by modulating mode control.

For example, when multistage information was " 0,1,0,1,0,7,6,7,6,7 ", though there is not continuity in multistage information, in the pattern with a plurality of " 0 " and a plurality of " 4 " formerly, the frequency component of 1/10 unit frequency was present in the signal really.In order to eliminate desired frequency fully, need add a large amount of redundant digits, and need to eliminate many patterns.

In fact, can not eliminate fully near hunting frequency with the swinging of signal component, and be desirably in the signal and keep some fluctuations.

When the fluctuation near hunting frequency be superimposed on signal on the time, the gain compensation of carrying out on swinging signal by VCA 140 is more than benefit according to the harm that the wave band (phase delay) that comprises the control loop of VCA 142 produces.

For example, if with signal and swinging signal in comprise the fluctuation of 1/10 unit frequency, if and the phase delay that comprises the control loop of VCA 142 is 1/5 unit frequency, the gain compensation of VCA 142 and VCA 140 will have anti-phase input, make described input, for example with the amplitude of signal or swinging signal when big, output is exaggerated, and when the amplitude of input hour, output is weakened.

In fact, high fdrequency component is removed at wave filter 141 places, and the adverse effect of gain compensation will be obvious not as above-mentioned example; Yet identical influence can occur in than on the low frequency of hunting frequency.

For fear of by because the continuity of multistage information is that cause misleads with fluctuation signal, S/H circuit 145 obtains and signal in bias pulse cycle or spacing pulse periodic process by sampling.In addition, in order to improve signal quality, the multistage recording of information that sampling can be limited in being scheduled to constantly.

For example, when recording level " 0 ", spacing pulse is longer, and when record mark " 7 ", bias pulse is longer.Therefore, when in each recurrence interval process, top signal level being taken a sample, can reduce because the sampling error that " error " of signal causes.

Then, the output signal of S/H circuit 145 is filtered at wave filter 141 places, makes the hunting frequency component by aforesaid elimination, and the sampling noise also is eliminated.

Therefore, for optimization, in response to the fluctuation of the reflectivity of medium track, gain is changed continuously, makes it possible to carry out best wobble signal detection.

Below, with the 5th wobble signal detection process of introducing in the multi-level recording.

Figure 15 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 5th wobble signal detection process for expression.

In this circuit structure, swinging signal is by in offset energy cycle and interval energy cycle process push-pull signal being taken a sample respectively and the signal Synchronization that obtains for each recurrence interval being obtained.

Circuit structure shown in Figure 15 comprises wave filter 120,

sample circuit

150 and 151, gain control (GC-a) circuit 152, gain control (GC-b) circuit 153 and be used for the totalizer 154 of wobble detection circuit shown in Figure 1 10.

Therefore, the circuit structure of Figure 15 has by with gain control signal with the unit frequency component is eliminated the signal that the unit frequency component obtains synthesize the function of extracting swinging signal the Laser emission periodic process of spacing pulse from the push-pull signal that detects, and wherein said signal by gain control is by the gain application of appointment is eliminated the signal that produces in the push-pull signal that the unit frequency component is detected from the Laser emission periodic process in bias pulse.

In this circuit structure, the unit frequency component is removed from push-pull signal at wave filter 120 places, and

sample circuit

150 and 151 receives the offset signal and the blank signal in expression spacing pulse cycle in expression bias pulse cycle respectively.The sampled signal of expression offset signal and blank signal can be bias pulse and spacing pulse itself, perhaps for example, in order to stablize push-pull signal, can handle described signal by fringe time arrangement, change width.

Then, be exaggerated at GC-a circuit 152 or GC-b circuit 153 places or weaken, and consequential signal is synthesized at totalizer 154 places and makes swinging signal to be extracted at sampled signal of their moment separately.

GC-a circuit 152 and GC-b circuit 153 are performed the purpose that is used for compensating the gain inequality between swinging signal component that the bias pulse periodic process obtains and the swinging signal component that obtains in the spacing pulse periodic process.Notice that GC-a circuit 152 changes so that signal difference is smooth in the present embodiment in gain, therefore can omit GC-b circuit 153.

In addition, the gain transformations method of GC-a circuit 152 can be carried out the D/A transducer 131 that uses in the second wobble signal detection process and the circuit structure of VCA circuit 132 is realized by being included in the multi-level recording.Selectively, the gain transformations method can realize by the selection of a plurality of resistances.

In addition, the totalizer of using in the present embodiment 154 can be replaced by a selector switch.In Figure 15,

sample circuit

150 and 151 is placed in after the wave filter 120; Yet the order of these circuit has nothing to do, and sample circuit can also be placed on before the wave filter.In this case, two wave filters are respectively placed on after two sample circuits.

In this embodiment, because light intensity is weak and the swinging signal component is the level that signal in the little bias pulse periodic process is enlarged into the signal level that equals the spacing pulse cycle therein, make can high-quality wobble detection signal so the component of signal of low output offset recurrence interval can be used effectively.

Below, introduce the 6th wobble signal detection process in the multi-level recording.

In the circuit structure of the 6th wobble signal detection process that is used for carrying out multi-level recording, each level that use is used for the sampling that will obtain at biasing cycle and spacing pulse periodic process and signal remains on each gain of a predetermined level, and the swinging signal component that detects in each recurrence interval process is exaggerated or weakens.

This circuit structure (not shown) is corresponding to circuit structure shown in Figure 15, but GC-a circuit 152 and GC-b circuit 153 have corresponding to GC circuit 121 shown in Figure 14 " inner structure.

Therefore, by synthetic first signal and secondary signal, described circuit structure has the function of extracting swinging signal, described first signal is by using and being used for and will remaining on the gain that the gain of a predetermined reference voltage equates with level signal in that the Laser emission periodic process of bias pulse is that detect, the signal that obtains eliminating in the push-pull signal that the unit frequency component is obtained from bias pulse Laser emission periodic process amplifies or weakens and obtains, and described secondary signal is by using and be used for and will remain on the gain that the gain of a predetermined reference voltage equates with level signal in that spacing pulse Laser emission periodic process is that detect, to elimination in the push-pull signal that the unit frequency component is obtained from spacing pulse Laser emission periodic process and the signal of acquisition amplifies or weakens and obtains.

In the circuit structure of the 6th wobble signal detection process that is used for carrying out multi-level recording, the bias pulse cycle is set to be used for the sample time of GC-a circuit 152, and the spacing pulse cycle is set to be used for the sample time of GC-b circuit 153.The sampled signal of representing sample time can be corresponding pulse itself or the impulse form of handling.And, notice that the reference voltage that is used for each signal is set as equal.

In this way, for optimization, variation corresponding to the reflectivity of the fluctuation of the Laser emission intensity in the multi-level recording recording of information process with periodic cycle or medium track, gain is by continuous change, and by with the bias pulse cycle (at this moment, light intensity is weak, and the swinging signal component is little) signal in the process is amplified to the level that equals the signal in the bias pulse periodic process, the component of signal of low output offset recurrence interval is used effectively, makes it possible to high-quality wobble detection signal best.

To introduce the 7th wobble signal detection process in the multi-level recording below.

Figure 16 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 7th wobble signal detection process for expression.Notice that those components identical parts shown in Figure 16 and Figure 15 provide with identical numeric character.

This circuit structure is most of consistent with structure shown in Figure 15, except the inner structure of GC-a circuit 152.The GC-a circuit 152 ' of Figure 16 uses in the gap periods process that obtain and level signal as reference voltage.

Therefore, by synthetic first signal and secondary signal, circuit shown in Figure 16 has the function of extracting swinging signal, described first signal is by using and being used for that and level signal detected at the Laser emission periodic process of bias pulse are remained on the gain that the gain of the level of detected and signal in the Laser emission periodic process of spacing pulse equates, the signal that obtains the unit frequency component is eliminated in the detected push-pull signal from bias pulse Laser emission periodic process amplifies or weakens and obtains, and described secondary signal is by the unit frequency component is eliminated the signal that obtains in the detected push-pull signal from spacing pulse Laser emission periodic process.

In this circuit structure, the wobble signal detection process in the bias pulse periodic process with in the circuit of Figure 15, carry out consistently; Yet the reference voltage that is used for GC-a circuit 152 ' obtains by following processes.

At first, S/H circuit 160 obtained and signal in the moment corresponding to the blank signal of representing the spacing pulse cycle.Then, at wave filter 162 places that the high fdrequency component that is higher than hunting frequency is removed to carrying out Filtering Processing and obtain reference voltage with signal.Reference voltage is transmitted to comparer 166 then.

And S/H circuit 161 obtains (sampling) and signal in the moment corresponding to the spacing pulse signal of representing the bias pulse cycle.Then, the high fdrequency component that is higher than hunting frequency at wave filter 163 places by from removing with signal and being exaggerated or weakening at voltage gain control amplifier (VCA) 165 from the signal of wave filter 163 outputs.Then, amplitude detection circuit 164 detections are from the amplitude of the output signal of VCA 165.And comparer 166 will be exported a voltage signal so that change the gain of VCA 167 from the output signal of VCA 165 and the Voltage Reference that reference voltage signal compares and basis passes through relatively to obtain.

In the present embodiment, fix owing to be used for the swinging signal gain in spacing pulse cycle, thus the GB-b circuit 153 that is used for determining this gain can be omitted, and can simplify circuit structure.

Therefore, according to present embodiment, for optimization, respective class seemingly has the such factor of variation of the reflectivity of the fluctuation of the Laser emission intensity in the multi-level recording recording of information process of periodic cycle or medium track, the variation that gain is repeated, and be amplified to by the signal level in the bias pulse cycle that will have low light intensity and little swinging signal component and equal the signal level of spacing pulse in the cycle, the component of signal of low output offset recurrence interval is effectively used, and makes the circuit that is used for the wobble detection signal to be simplified and can be with high-quality wobble detection signal accurately.

Below, be the CD 13 of optical information recording medium according to an embodiment of the invention with introducing.

For example, CD 13 stipulates that the swinging signal frequency that is suitable for multistage information record is not higher than 1/10 unit frequency.

In the twin-stage record, information is represented that by the length of the mark that is write down therefore, size occurs at random for the mark of 3T-11T (T is the basic cycle).In this case, the data wave band is wide and does not have the strong output of specific frequency components.

Yet in multi-level recording, therefore the cycle of each mark the strong output of unit frequency component will occur, and the strong output of the frequency component of 1/2nd unit frequencies occur in playing process corresponding to its unit during writing down.

The frequency component of the multistage information organized continuously can be controlled at a definite degree by limiting multistage modulation control as discussed previously.Especially, for example, when multistage value representation is " n ", and the unit periodic table of the multistage information that will be conditioned is when being shown " m ", m the power (n of n ^m) quantity of information managed and the combination of from every group of " m " individual unit, having eliminated to have big frequency component (continuous mode of multistage information).

It is taken into account in the multistage information modulation of restriction the broadband of the managerial demand management information of the frequency component more much lower than unit frequency.

On the other hand, frequency component is more near unit frequency, and information density is high more, thereby makes modulation efficiency descend, and recording capacity descends conversely.Therefore, provided specific value below as an example.

According to the value of CD, DVD, the amplitude of swinging signal be approximately play signal amplitude peak 1/20.

Figure 17 is the curve map of the characteristic of explanation CD 13 according to an embodiment of the invention.

In the figure, represent the signal intensity of hunting frequency components in the bold line 70 at hunting frequency place, and represent the play signal intensity in the bold line 71 at play signal frequency place.

When in LOG shows ratio 1 to 20 being set, though depend on the frequency of play signal corresponding to the superposition point of the play signal in the boundary line that is used to extract swinging signal, the superposition point is equal to or less than wobble signal amplitude.

In addition, in circuit, preferably use postifiler, and therefore, for example, can obtain to be used to weaken 1/20 or frequency still less of play signal, and for example the play signal frequency can be set to 5 times hunting frequency or higher.

Filtering characteristic by dot-and-dash line 72 expressions has the function of eliminating the frequency that is higher than hunting frequency, and as shown in FIG., attenuation characteristic is enhanced along with the increase of signal frequency component.Here, the play signal frequency preferably is set to have 1/20 or the frequency of attenuation rate still less.

Because the strongest play signal frequency is corresponding to 1/2 unit frequency (because one-period is corresponding to two unit), so unit frequency is bigger 10 times than hunting frequency; Just, hunting frequency is preferably lower than 1/10 of unit frequency.

In this way, swinging signal can be separated in the unit frequency component of strong superposition from various signals recording process, makes it possible to obtain outstanding signal quality.

And the optical disc apparatus of the application of the invention writes down multistage information on CD 13, can make register system stable.

In addition, by by means of the multistage information of optical disc apparatus playback of recorded of the present invention on CD 13, can make Play System stable.

Below, introduce the servosignal testing process in the multi-level recording according to a preferred embodiment of the invention.

Figure 18 is the block scheme of four minutes optical receiver; And Figure 19 is the block scheme that is used for realizing at multi-level recording according to an embodiment of the invention the circuit structure of the first servosignal testing process.

As the example of the circuit structure of the first servosignal testing process that is used for realizing multi-level recording, receive catoptrical optical receivers (PD) from CD 15 and can be split into as shown in figure 18 four parts.Here, divided receiver part 5A-5D sends to I/V circuit 8a-8d with their output respectively.I/V circuit 8a-8d carries out voltage transformation to produce signal VA-VD respectively on the basis of reflected signal.

Slightly (raw) focus error signal is corresponding to (VA+VD)-(VB+VC), and thick (raw) tracking error signal is corresponding to (VA+VC)-(VB+VD).Thick focus error signal and thick tracking error signal only just can not obtain by handling by calculating; Therefore, these signals are called the coarse servo signal.The coarse servo signal comprises high fdrequency component, and the zone of for example reading is that Unrecorded swinging signal component and described zone are the data-signal components (unit frequency component) that has write down.Therefore, as shown in figure 19, be used to eliminate the wave filter 216 and 217 of high fdrequency component to eliminate unnecessary noise.

Then, being set to gain control (GC) circuit 218 and 219 that is used to the signal amplitude that obtains to expect through the signal of filtering amplifies or reduces to produce servosignal, for example focus error signal and tracking error signal.Here, notice that the computing method that are used for thick focus error signal and thick tracking error signal can change according to optical receiver system, thereby described computing method are not limited to top example.And, though not shown, according to identical process, can detect the servosignal of other type, the track cross signal that obtains by (VA+VB+VC+VD) for example.

In other words, wave filter 216 and 217 has from the coarse servo signal that detects at optical information recording medium removes high fdrequency component, for example the function of swinging signal component.GC circuit 218 and 219 has from the function by extraction servosignal the signal of removing the high fdrequency component acquisition from the coarse servo signal.

Yet in recording process, the intensity of laser output is modulated, so the quality of servosignal has been lowered.

Especially, by there not being the recording laser emission of bias pulse, when writing down big record mark one by one, can not guarantee sense cycle effectively.On the other hand, use the recording laser emission that comprises bias pulse, in the bias pulse periodic process, can carry out input effectively.

Because servosignal is difference signal, so the laser intensity modulation product only influences the changes in amplitude of servosignal component ideally.

Yet, in fact, for example, may take place because the variation of the intensity between four parts of the variation of the axle of lens that the inclination of medium causes and ray or divided optical receiver part, therefore, the intensity modulated component of laser is superimposed on the servosignal, and the result has caused the deterioration of servosignal.

Below, be described in further detail top problem with referring again to Figure 11 A-11D, the situation of the record mark of record same size on continuous unit has been described in Figure 11 A-11D.

As previously explained, when because certain type fluctuation and when intensity difference having occurred on the optical receiver that four cut apart, the reflected signal in recording process is retained in the coarse servo signal, thereby becomes the noise of servosignal component.

In other words, in multi-level recording, be easy to the unit frequency component is carried out strong superposition, therefore, in the circuit structure of the first servosignal testing process that is used for carrying out multi-level recording, wave filter 216 and 217 is inserted into to eliminate the unit frequency component.

And according to the form of CD (recording medium) 13, the swinging signal of the velocity of rotation that is used for control medium that the track that forms from medium obtains may be become noise by superposition.In this case, these components also are eliminated simultaneously.

In addition, be used for the system of high-speed record, reflected signal also is subjected to the influence from write pulse and low pulse, and the filtering characteristic that therefore can eliminate the frequency component that is higher than unit frequency is preferred.Just, described wave filter is preferably the low-pass filter that is used to remove the frequency component that is higher than the minimum wobble signal frequency.And GC circuit 218 and 219 is arranged on the basis of the output of wave filter 216 and 217 and carries out gain compensation so that the amplitude of servosignal is suitably regulated.

In this way, high fdrequency component corresponding to the swinging signal of unit frequency component is eliminated, thereby the deterioration that has the servosignal in the short useful signal cycle that obtains by the Laser emission that is used for multistage information record can be prevented from, and can detect high-quality servosignal.

Next, with the second servosignal testing process of introducing in the multi-level recording.

Figure 20 is used for carrying out at multi-level recording the block scheme of the circuit structure of the second servosignal testing process for expression.

In multi-level recording, carry out in the circuit structure of the second servosignal testing process, can detect the servosignal of a certain signal quality level with simple circuit configuration.

In general, can make Laser emission intensity optimization, make and to write down high-quality multistage information by before user data, implementing to test to write.Here, preferably the optimum gain of swinging signal changes along with the variation of the light intensity of laser beam.

Being used to as shown in figure 20, the circuit structure of carrying out the second servosignal testing process comprised wave filter 220 and as gain control (GC) circuit 221 of laser control circuit shown in Figure 17 and servo testing circuit 11.

In addition, GC circuit 221 comprises laser control circuit 7, CPU 230, D/A transducer 231 and VCA 232.

Just, GC circuit 221 shown in Figure 20 has such function: use and to calculate at least one value of setting that obtains according to the light intensity of the light intensity of the bias pulse that is used for determining gain and spacing pulse and extract servosignal, described gain will be used to by from the high fdrequency component of coarse servo signal elimination swinging signal or the signal that the unit frequency component obtains.

In GC circuit 221, the light intensity of Laser emission manages by CPU 230, and just, CPU 230 is provided with the optimal light intensity level for laser control circuit.Selectively, laser control circuit 7 itself can be set to and be used to read current light intensity setting.

According to the light intensity setting, CPU 230 calculates the average laser emission measure by the empty filtering acquisition of light intensity modulation component, and is that D/A transducer 231 is provided with suitable value to determine the gain of VCA 232.

The gain of VCA 232 changes according to the output voltage of D/A transducer 231.The average laser emission measure can obtain according to the generation rate by pulse width, light intensity and the multistage information of each pulse of CPU management.

Therefore, in order to guarantee the purpose of recording quality by simple circuit structure, gain is changed to the continually varying optimum value corresponding to recording light intensity, and can carry out suitable servosignal testing process.

Below, with the 3rd servosignal testing process of introducing in the multi-level recording.

Figure 21 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 3rd servosignal testing process for expression.

The variation of mean value that this circuit structure is used for the reflected signal (and signal) of collaborative recording process realizes stablizing servo testing process.

Because the variation of the reflectivity of dielectric surface or track or the fluctuation and the signal of laser intensity (being lower than the frequency of the modulation product of each pulse) change at the low frequency place.In addition and signal change according to the continuity of multistage information.Fluctuation on these broadbands is as the factor affecting servosignal that is used to change gain.

Therefore, be used for carrying out the circuit of the 3rd servosignal testing process, can prevent above-mentioned problem at multi-level recording by employing.

This circuit structure shown in Figure 21 comprises wave filter 220 and as gain control (GC) circuit 221 ' of servo testing circuit 11 shown in Figure 1.

GC circuit 221 ' comprises VCA 240, wave filter 241, VCA 242, amplitude detection circuit 243 and comparer 244.

Just, by using the gain that equates with the gain that is used for to maintain a predetermined reference voltage by level from a signal the high fdrequency component elimination being obtained with signal, the signal that will obtain by the high fdrequency component of eliminating from the coarse servo signal corresponding to swinging signal or unit frequency amplifies or reduces, and GC circuit 221 ' shown in Figure 21 has the function of extracting servosignal.

In this circuit structure, high fdrequency component wave filter 241 places by from signal eliminate, and be exaggerated at voltage gain control amplifier (VCA) 242 places or reduce from the output signal of wave filter 241.Then, detected at amplitude detection circuit 243 places from the amplitude of the output signal of VCA 242, and compared with predetermined reference voltage at comparer 244 places from the output signal of VCA 242.Be output corresponding to voltage, make the gain of VCA 242 be changed by the difference that relatively obtains.

Because this loop, the gain Be Controlled of VCA 242 makes the amplitude output signal of VCA 242 reach predetermined reference voltage.As for the coarse servo signal, high fdrequency component, for example unit frequency component and swinging signal (hunting frequency component) are removed at wave filter 220 places, are exaggerated by VCA 240 or reduce through the signal of filtering afterwards.The gain of VCA 240 equals the gain of VCA 242.

Continuously change gain so that gain optimization can realize the optimum servo input by reflectivity fluctuation corresponding to Laser emission strength fluctuation that occurs in the process with periodic cycle record multi-level recording information or medium track.

Below, with the 4th servo testing process of introducing in the multi-level recording.

Figure 22 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 4th servosignal testing process for expression.Notice that the part identical with those parts shown in Figure 21 is given identical numeric character.

This circuit structure is closely similar with the circuit structure that is used in multi-level recording execution the 3rd servosignal testing process; Yet the circuit structure among Figure 22 further comprised sample-and-hold circuit 245 before wave filter 241, and the sampled signal that obtains during sampling process in the cycle with bias pulse cycle or spacing pulse is used as basic signal, rather than the mean value of use and signal.

Therefore, by using and being used for and maintaining the gain that the gain of a predetermined reference voltage equates with level signal in that the Laser emission periodic process of Laser emission cycle of bias pulse or spacing pulse is that obtain, the signal that will obtain by the high fdrequency component of eliminating similar swinging signal or unit frequency component from the coarse servo signal amplifies or reduces GC circuit 221 shown in Figure 22 " have a function of extracting servosignal.

Because the circuit structure that is used for carrying out the 4th servosignal testing processes at many records is identical with the circuit structure major part that is used to carry out the 3rd servosignal testing process, so will introduce the different characteristic of latter's structure, that is, S/H circuit 245 and the signal that inputs to wave filter 241.

As mentioned above and signal comprise the fluctuation that relates to multistage information continuity.For example, the multistage information when ten sequential cells is: when " 0,0,0,0,0,4,4,4,4,4 " and signal comprise the fluctuation of frequency component with 1/10 unit frequency.Ideally, for cross frequence, modulating mode is in multistage stage of modulating Be Controlled, make and the fluctuation of signal be prevented from appearing at servo signal frequency around.Modulating mode control is included in by adding that redundant digit has increased the use of eliminating special pattern after the quantity of information.

This means that conversely recording density has been reduced, thereby the advantage that obtains higher density in the multi-level recording method has been reduced.In addition, different with the twin-stage record, in multi-level recording, it may be difficult obtaining separating fully of frequency by modulating mode control.

For example, when multistage information is " 0,1,0,1; 0,7,6,7,6; 7 " the time, though in multistage information, there is not continuity, in signal, there is the frequency component of 1/10 unit frequency really, the same in pattern formerly with a plurality of " 0 " and a plurality of " 4 ".For desired frequency is eliminated fully, need add a considerable amount of redundant digits and need to eliminate many patterns.

In fact, can not eliminate fully in the servo wave band and signal fluctuation, and be desirably in the signal and keep some fluctuation.

When near the fluctuation of servo wave band by superposition with signal on the time, the gain compensation that carries out on servosignal by VCA 240 is more than benefit according to the harm that the wave band (phase delay) that comprises the control loop of VCA 242 produces.

For example, if with signal and servosignal in the fluctuation of 1/10 unit frequency is arranged, if and the phase delay that comprises the control loop of VCA 242 is 1/5 unit frequency, the gain compensation of VCA 242 and VCA 240 will have anti-phase input so, make when such as with the amplitude of the input of signal or servosignal greatly the time, output is exaggerated, and when the amplitude of described input hour, described output is reduced.

In fact, owing to high fdrequency component is eliminated at wave filter 241 places, so the retroaction of gain compensation is obvious unlike above-mentioned example; Yet identical effect can appear on the frequency that is lower than hunting frequency.

For fear of being reduced with fluctuation signal by the continuity by multistage information is that cause, S/H circuit 245 obtains and signal in bias pulse cycle and spacing pulse periodic process by sampling.In addition, in order to improve signal quality, the multistage recording of information that sampling can be limited in being scheduled to constantly.

For example, when recording level " 0 ", spacing pulse is longer, and when recording level " 1 ", bias pulse is longer.Therefore, when in each recurrence interval process, top signal level being taken a sample, can be reduced by " error " caused sampling error of signal.

Then, the output signal of S/H circuit 245 is filtered at wave filter 241 places, make high fdrequency component by as eliminate above-mentionedly, and the sampling noise also be eliminated.

Therefore, corresponding to the fluctuation of medium track reflectivity, gain is changed to optimization continuously, makes the optimum servo input to be performed.

Below, with the 5th servosignal testing process of introducing in the multi-level recording.

Figure 23 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 5th servosignal testing process for expression.

In this circuit structure, servosignal is by in bias pulse cycle and spacing pulse periodic process the coarse servo signal being taken a sample respectively and these signals that each recurrence interval obtains being synthesized acquisition.

Circuit structure shown in Figure 23 comprises wave filter 220,

sample circuit

250 and 251, gain control (GC-a) circuit, gain control GC-b circuit 253 and as the totalizer 254 of servo testing circuit 11 shown in Figure 1.

Therefore, the circuit structure of Figure 23 has the function of extracting servosignal by synthetic first signal and secondary signal, described first signal is to produce by the signal that the high fdrequency component of eliminating from detected coarse servo signal the Laser emission periodic process of bias pulse corresponding to swinging signal or unit frequency obtains by predetermined gain is applied to, and secondary signal is to obtain by eliminating from detected coarse servo signal the Laser emission periodic process of spacing pulse corresponding to the high fdrequency component of swinging signal or unit frequency.

In this circuit structure, the high fdrequency component of swinging signal or unit offset frequency rate component is removed from the coarse servo signal at wave filter 220 places, and each

sample circuit

250 and 251 receives the offset signal and the blank signal in spacing pulse cycle in bias pulse cycle respectively.The sampled signal of expression offset signal and blank signal can be bias pulse or spacing pulse itself, and perhaps described signal can be for example, by fringe time arrangement, change width and processed, so that the coarse servo signal stabilizationization.

Then, be exaggerated at GC-a circuit 252 and GC-b circuit 253 places or reduce, and the signal that the result obtains is synthesized at totalizer 254 places, make servosignal be extracted at their each signal of taking a sample constantly.

GC-a circuit 252 and GC-b circuit are implemented the gain inequality that is used for compensating between servosignal component that the bias pulse periodic process obtains and the servosignal component that obtains in the spacing pulse periodic process.Notice that it is poor with erasure signal that GC-a circuit 252 changes in gain in the present embodiment, therefore, the GC-b circuit can be omitted.

And the change in gain method of GC-a circuit 252 can realize by the circuit structure that comprises D/A transducer 231 and VCA circuit 232 shown in Figure 20.Selectively, the change in gain method can realize by the selection of a plurality of resistances.

In addition, the totalizer of using in the present embodiment 254 can be replaced by selector switch.In Figure 23,

sample circuit

250 and 251 is disposed in after the wave filter 220; Yet the order of these circuit is incoherent, and sample circuit can be placed on before the wave filter.In this case, two filter circuits are arranged in after two sample circuits.

In this embodiment, because light intensity is weak and the servosignal component is that signal in the little bias pulse periodic process is enlarged into the level that equates with the signal level in spacing pulse cycle therein, so the component of signal of low output offset recurrence interval can be used effectively, make it possible to detect and have high-quality servosignal.

Below, introduce the 6th servosignal testing process in the multi-level recording.

Be used in the circuit structure of multi-level recording execution the 6th servosignal testing process, remain on a certain level by what be used for the sampling process from each bias pulse cycle and spacing pulse cycle is obtained with signal level, the servosignal component is exaggerated simultaneously or reduces.

This circuit structure is corresponding to circuit structure shown in Figure 23, but the inner structure of GC-a circuit and GC-b circuit is corresponding to GC circuit 221 shown in Figure 22 " inner structure.

Therefore, the circuit structure of Figure 23 has the function of extracting servosignal by synthetic first signal and secondary signal, described first signal is by using and being used for and will maintaining the gain that the gain of a predetermined reference voltage equates with level signal in that the Laser emission periodic process of bias pulse is that detect, amplify or reduce and produce will from the coarse servo signal that the Laser emission periodic process of bias pulse, detects, eliminating the signal that obtains corresponding to the high fdrequency component of swinging signal or unit frequency component, and secondary signal is by using and be used for and will maintain the gain that the gain of a predetermined reference voltage equates with level signal in that the Laser emission periodic process of spacing pulse is that detect, to amplifying corresponding to the high fdrequency component picked up signal of swinging signal or unit frequency component by elimination in the thick signal that detects from the Laser emission periodic process of spacing pulse or reducing to obtain.

Be used in the circuit structure of multi-level recording execution the 6th servosignal testing process, the bias pulse cycle is set to be used for the sample time of GC-a circuit 252, and the spacing pulse cycle is set to be used for the sample time of GC-b circuit 253.The sampled signal of representing sample time can be the corresponding pulse itself or the treated form of pulse.And, notice that the reference voltage that is used for each signal is set to equate.

In this way, variation corresponding to the reflectivity of the fluctuation of the Laser emission intensity in the multi-level recording recording of information process with periodic cycle or medium track, gain is become optimization continuously, and by will be therein light intensity be weak and the swinging signal component is that signal in seldom the bias pulse periodic process is amplified to a level that equates with signal level at the spacing pulse periodic process, the component of signal of low output offset recurrence interval is used effectively, make have a high-quality servosignal can be by suitable detecting.

To introduce the 7th servosignal testing process in the multi-level recording below.

Figure 24 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 7th servosignal testing process for expression.Notice that shown in Figure 24 those partly are given identical numeric character with Figure 23 components identical.

This circuit structure is identical with circuit structure major part shown in Figure 23, except the inner structure of GC-a circuit 252.The GC-a circuit 252 ' use of Figure 24 level conduct that obtain and signal in the spacing pulse periodic process is used for the reference voltage of GC-a circuit 252 '.

Therefore, the circuit of Figure 24 has the function of extracting servosignal by synthetic first signal and secondary signal, described first signal is by using and being used for and will keeping the gain that gain that detect and level signal equates in the Laser emission periodic process that is spacing pulse with level signal in that the Laser emission periodic process of bias pulse is that detect, amplify or reduce and produce will from the coarse servo signal that the Laser emission periodic process of bias pulse, detects, eliminating the signal that obtains, and secondary signal is by eliminating acquisition the Laser emission periodic process of spacing pulse from the coarse servo signal that detects corresponding to the high fdrequency component of swinging signal or unit frequency corresponding to the high fdrequency component of swinging signal or unit frequency component.

In this circuit, the servosignal testing process in the bias pulse periodic process with in the circuit of Figure 23, carry out identical; Yet the reference voltage that is used for GC-a circuit 252 ' obtains according to following processes.

At first, S/H circuit 260 obtained and signal in the moment corresponding to the blank signal of representing the spacing pulse cycle.Then,, make high fdrequency component be eliminated and obtain reference voltage carrying out Filtering Processing at wave filter 262 places with signal.Reference voltage is sent to comparer 266 then.

And S/H circuit 261 obtains (sampling) and signal in the moment corresponding to the bias pulse signal of representing the bias pulse cycle.Then high fdrequency component wave filter 263 places by from signal remove, and the output signal of wave filter 263 is exaggerated at voltage gain control amplifier (VCA) 265 places or reduces.Then, amplitude detection circuit 264 detects the amplitude of the output signal of VCA 265.And comparer compares and exports corresponding to the voltage by the voltage difference that relatively obtains the output signal of VCA 265 and reference voltage signal so that change the gain of VCA 267.

In the present embodiment, fix owing to be used for the servosignal gain in spacing pulse cycle, thus be used for determining that the GC-b circuit 253 of this gain can be omitted, and circuit structure can be simplified.

Therefore, according to present embodiment, the circuit that is used to detect servosignal can be simplified, in this circuit, corresponding to similar in having the multi-level recording recording of information process of periodic cycle the Laser emission strength fluctuation or the such factor of variation of the reflectivity of medium track, optimization is changed in gain iteratively, and be amplified to by the signal level in the bias pulse cycle that will have low light intensity and little servosignal component and equal the signal level of spacing pulse in the cycle, the component of signal of low output offset recurrence interval is used effectively, makes it possible to accurately detect have high-quality servosignal.

Below, with the 8th servosignal testing process of introducing in the multi-level recording.

Figure 25 is used for carrying out at multi-level recording the block scheme of the circuit structure of the 8th servosignal testing process for expression.

Figure 26 A-26B is for illustrating the synoptic diagram of the 8th servosignal testing process of being carried out by circuit shown in Figure 25 in multi-level recording.

As shown in figure 25, in this circuit structure, phase compensating circuit 270 is disposed in after the servo testing circuit shown in Figure 1 11 with the phase properties that obtains according to the closed loop that is used for controlling the position of laser beam on medium the servosignal excute phase compensation according to any one acquisition of first to the 7th servosignal testing process.

Therefore, phase compensating circuit 270 has the function that the servosignal to any one acquisition in detecting according to first in the multi-level recording to the 7th servosignal carries out phase compensation.

In laser beam position control, because mechanical constraint can not be provided with very highly with crossover frequency (frequency when the closed loop gain characteristic is 0dB).

In Figure 26 A, line [a] expression crossover frequency is the simplest gain characteristic of ω 1.On the other hand, for the retentive control precision, laser beam position control goes for the low band fluctuation, and the gain characteristic of for example medium rotational component, so closed loop can be set to have high-gain on low band.Satisfying the simple gain characteristic of this condition is represented by the line among Figure 26 A [b].Yet, in this case, crossover frequency exceed mechanical constraint for the upper frequency place of ω 2.

Phase compensating circuit 270 can be used under this situation.Figure 26 B shows the autonomous behavior of phase compensating circuit 270.As shown in this Fig, gain changes in wave band Δ ω.When change in gain, phase delay around this wave band Δ ω, occurred, but postponed only to appear in this zone.

By making servosignal pass through phase compensating circuit 270, when crossover frequency is remained on ω 1, can on low band, guarantee high-gain.In the present embodiment, phase-delay network is given the example of making phase compensating circuit 270; Yet, can replace it to be used to guarantee leading (lead) circuit of phase place of crossover frequency guiding (lead) on every side.

According to present embodiment, for the laser beam position on the control medium, servosignal is carried out phase compensation, and therefore can obtain to satisfy the servosignal characteristic of mechanical condition and control accuracy requirement.

And, by the structure of above-mentioned therein optical devices, can realize stable recording played system in the multistage information of record on the CD 15 and the multistage information on the CD 15 that is recorded in of resetting.

By servosignal detection method in the multi-level recording according to the present invention and optical information recording playing device, being suitable for writing down the servosignal of multistage information by write pulse, low pulse, spacing pulse and bias pulse can be detected.

The application based on Japanese patent application 2002-346800 number that on November 29th, 2002-25917 number 1 proposed with the Japanese patent application that requires to propose on September 4th, 2002 and the Japanese patent application that proposed on November 29th, 2002 2002-346820 number formerly in please day right of priority, the whole content of these applications here by with reference to and merged.

Claims

1. optical information recording medium comprises:

The zone that is divided into approximately equalised a plurality of unit forms according to the information that will be recorded on described zone and can be the mark of multiple size; Wherein

The frequency of detected swinging signal is no more than 1/10 of unit frequency from the track swing of being carried out.

2. device for optical information recording, comprise the unit that is suitable for the multistage information of record on optical information recording medium, described medium has the zone that is divided into approximately equalised a plurality of unit, record forms the mark that can be multiple size according to the information that will be recorded on described unit, and wherein the frequency of detected swinging signal is not higher than 1/10 of unit frequency from preformed track swing.

3. optical information playing device, comprise the unit that is suitable for the multistage information of playback of recorded on optical information recording medium, described medium has the zone that is divided into approximately equalised a plurality of unit, the information that basis is recorded on described unit forms and can be the mark of multiple size, and wherein the frequency of detected swinging signal is not higher than 1/10 of unit frequency from preformed track swing.