JP4120950B2 - Optical disk apparatus and recording method therefor - Google Patents

Description

  The present invention relates to an optical disk apparatus and a recording method thereof, and is applied to an optical disk apparatus that records desired information by heating the information recording surface by irradiating an information recording surface formed of an organic dye, for example. obtain.

Conventionally, some optical disk apparatuses of this type can record desired information by switching the amount of light beam between the read power and the write power.
That is, in an optical disk applied to this type of optical disk apparatus, an organic dye is attached to a polycarbonate disk-shaped substrate to form an information recording surface, and this information recording surface is protected by a protective layer.

  On the other hand, the optical disk device irradiates the information recording surface with a light beam to thermally change the organic dye, thereby forming a low reflectance region on the information recording surface. As a result, the optical disk apparatus records the desired information by sequentially forming the same pits as the compact disk on the information recording surface.

  In this information recording, this type of optical disk is preliminarily formed with a spiral pre-groove on the information recording surface so that a pitch can be reliably formed at a predetermined recording track forming position. In, tracking control is performed with reference to the pregroove by receiving the reflected light of the light beam.

  That is, as shown in FIG. 4, in this type of optical disc apparatus, the data to be recorded is EFM modulated to generate a modulation signal S1 (FIG. 4A), and the timing of this modulation signal S1 is set as necessary. The recording signal S2 is generated by correcting (FIG. 4B). The modulation signal S1 is formed such that the period of H level and L level continues in a range of 3T to 11T with a predetermined reference period T as a reference, and the recording signal S2 is formed of this modulation signal as indicated by a broken line. It is formed by correcting the falling timing of S1.

  Accordingly, the optical disk device switches the light amount of the light beam L1 between the read power R and the write power W in accordance with the signal level of the recording signal S2 (FIG. 4C), and the light beam L1 is changed to information on the optical disk. Condensed on the recording surface. As a result, when the temperature of the optical disk rises as the light beam L1 is switched to the light power W, the organic dye changes and the reflectance decreases. In the optical disk apparatus, the modulation signal is sequentially transferred to the scanning locus of the light beam L1. A pit P (FIG. 4D) corresponding to S1 can be formed.

Along with the change in reflectivity during the formation of the pit, the reflected light obtained from the optical disk increases substantially immediately after switching to the light power W, and the light intensity decreases as the reflectivity decreases when the pit P begins to be formed. Then, when switching to the lead power R, the irradiation position of the light beam is extremely lowered until it is located outside the pit P that has been formed so far, and then only the portion with high reflectivity is scanned. Then, it rises to a predetermined light intensity.
As a result, in the reproduction RF signal RF that is the result of receiving the reflected light amount, the signal level greatly changes following the change in the reflected light amount (FIG. 4E).

  For this reason, in this type of optical disk apparatus, as shown by the arrow, the output signal of the light receiving element is sampled and held immediately before the light amount is switched from the read power R to the write power W, and the tracking error is determined based on the sample hold result. A signal is formed. That is, in the lead power R, the light reception result similar to that at the time of information reproduction can be obtained if the output signal of the light receiving element is sampled and held at the timing when the signal level of the reproduction RF is stabilized by the light amount at the time of information reproduction. . As a result, the optical disc apparatus detects the deviation of the light beam irradiation position with respect to the pre-groove based on the sample hold result and performs tracking control.

However, in actuality, when the tracking error signal is generated by sample-holding the light reception result in this way, tracking control is performed for a period of up to 22 T with reference to the sample-hold result sampled and held immediately before switching to the write power W. It will be.
For this reason, the conventional optical disk apparatus has a problem that the accuracy of tracking control is lowered during recording.
In addition, when sample-holding at the timing immediately before switching to the write power W as described above, there is a problem that tracking accuracy is lowered due to the influence of noise or the like.

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose an optical disk device capable of tracking control with high accuracy.

In order to solve this problem, in the present invention, the light beam is switched between the write power and the read power, and the desired information is applied to the disk-shaped recording medium by irradiating the predetermined beam-shaped recording medium with the light beam. EFM modulated and recorded, or in the optical disc apparatus for reproducing the EFM modulated information, to a plurality of sample-and-hold means is generated by the first sample-and-hold means provided to generate a Fuoka Suera signal Focus control is performed based on the focus error signal, and the first sample hold means receives the reflected light of the light beam obtained from the disk-shaped recording medium on a plurality of light receiving surfaces and outputs the light from the plurality of light receiving surfaces. When the received light signal forms three or four periods with respect to the reference period of EFM modulation, No sampling is performed during this period, and the value when sampling is performed during the previous read power period with respect to the read power period is held in the write power period, and is output as a light reception signal, which is output from a plurality of light receiving surfaces. When the received light signal is longer than 3 cycles or 4 cycles with respect to the EFM modulation reference cycle, the value sampled in the read power period is held in the write power period, and is output as the received light signal to perform the focus control. By generating a focus error signal, the amount of reflected light is stabilized so that the received light signals output from the plurality of light receiving surfaces form three or four periods with respect to the reference period of the EFM modulation. Even in the case of extremely short lead power periods, the output of high frequency components and noise Reduce contamination of less error can be obtained a high Fuokasu signal effect is less accurate noise, thus further makes it possible to improve the accuracy of the focus control of the optical disc system, the further optical disc system Recording density can be improved.

As described above, according to the present invention, the focus control is performed on the plurality of sample and hold means based on the focus error signal generated by the first sample and hold means provided to generate the focus error signal. The first sample-and-hold means performs the read power period when the light-receiving signals output from the plurality of light-receiving surfaces of the optical disk device form three or four periods with respect to the EFM modulation reference period. without sampling, by which is adapted to generate a focus error signal using the output of the hold received signal values in the period of the write power when sampled at a period of Ridopawa immediately before for the duration of the Ridopawa, Fuo Since unnecessary high frequency components and noise can be reduced in the error signal, the error is reduced. Focus signal can be obtained with high accuracy even when the received light signal has a period as short as 3 or 4 with respect to the reference period of EFM modulation. It is possible to realize an optical disk device that can be used.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Configuration of Embodiment In FIG. 1, reference numeral 1 denotes an optical disk device as a whole, which records and reproduces desired information on an optical disk 2 having an information recording surface formed of an organic dye.
That is, in the optical disk device 1, a predetermined reference signal is generated by the spindle PLL circuit 3, and the driver 4 is driven by this reference signal, so that the optical disk 2 is rotationally driven by the spindle motor 5.

In this state, the optical disk device 1 inputs the EFM modulation signal S1 to the timing generation circuit 6 at the time of recording, generates a predetermined reference signal here, and also generates a recording signal S2, and this recording signal S2 is a laser driver. 7 is output.
Here, the laser driver 7 drives a laser diode that forms the optical pickup 8 based on the recording signal S2.

The optical pickup 8 condenses the emitted light L1 of the laser diode on the information recording surface of the optical disk 2 through a predetermined optical system, whereby the optical disk device 1 responds to the recording signal as shown in FIG. Then, the light quantity of the light beam L1 is switched, and this light beam L1 is applied to the optical disk 2 (FIG. 2A).
At this time, the optical pickup 8 moves the focus lens 9 and the tracking coil 10 with a predetermined drive signal to move the objective lens for condensing the light beam L1 on the information recording surface of the optical disk 2 vertically and horizontally. Thus, the optical disk device 1 can perform the focus control and tracking control by driving the focus coil 9 and the tracking coil 10 with reference to the focus error signal and the tracking error signal. Has been made.

Further, the optical pickup 8 receives the reflected light of the optical disk 2 through the objective lens and guides the reflected light to a predetermined light receiving element.
Here, as shown in FIG. 3, the light receiving element includes a first light receiving element 12 in which a rectangular light receiving surface is divided into four regions A to D in a square shape, and a rectangular light receiving surface is divided into two parts. The optical pickup 8 has a light receiving surface A to D of the first light receiving element 12 in the radial direction and the circumference of the optical disc 2, respectively. Further, the second light receiving elements are arranged at a position off-tracked by a predetermined distance in the circumferential direction of the optical disk 2 with respect to the first light receiving elements 12 so as to be aligned in the direction.

Thus, the optical pickup 8 forms an optical system so that the reflected light is condensed on the first and second light receiving elements 12 and 13.
Further, the optical pickup 8 has a head amplifier board 14 built therein, and the head amplifiers 15A to 15F mounted on the head amplifier board 14 amplify and output the output signals of the respective light receiving surfaces A to F. Of these, the first light receiving element The output signals of the head amplifiers 15A to 15D that amplify the 12 output signals are added and amplified by the head amplifier 15RF and output. As a result, the optical pickup 8 generates and outputs a reproduction RF signal RF.

On the other hand, the matrix board 16 has a plurality of amplifier circuits 17A to 17I, and inputs the output signals of the head amplifiers 15A and 15C and the head amplifiers 15B and 15D to the first and second amplifier circuits 17A and 17B, respectively. By adding and amplifying, added signals A + C and B + D of the output signals SA, SC and SB and SD are generated between the light receiving surfaces A and C and the light receiving surfaces B and D arranged in the diagonal direction of the light receiving element 12, respectively.
Further, the matrix board 16 inputs the output signals of the head amplifiers 15A and 15D and the head amplifiers 15B and 15C to the third and fourth amplifier circuits 17C and 17D, respectively, and amplifies the signals in the circumferential direction of the optical disk 2. The addition signals A + D and B + C of the output signals SA, SD and AB and SC are generated between the light receiving surfaces A and D and the light receiving surfaces B and C of the light receiving elements 12 arranged side by side.

Further, the matrix board 16 inputs the output signals of the head amplifiers 15E and 15F to the fifth and sixth amplifier circuits 17E and 17F, respectively, thereby outputting the output signals of the respective light receiving surfaces E and F of the second light receiving element 13. While amplifying and outputting, the input signals of the third and fourth amplifier circuits 17C and 17D are input to the seventh and eighth amplifier circuits 17G and 17H for amplification, and the head amplifier is applied to the ninth amplifier circuit 17I. A reproduction RF signal RF, which is an output signal of 15 RF, is input and amplified.
As a result, the optical disk device 1 can reproduce the information recorded on the optical disk 2 by processing the reproduction RF signal RF output from the amplifier circuit 17I by inputting it to a predetermined signal processing circuit during reproduction. Has been made.

Further, the matrix board 16 is provided with sample hold circuits 18A to 18H so as to correspond to the first to eighth amplifier circuits 17A to 17H, and the first to eighth amplifier circuits are provided to the sample hold circuits 18A to 18H. The output signals 17A to 17G are input.
Of these, the seventh and eighth sample-and-hold circuits 18G and 18H remove the DC component by inputting the output signals of the amplifier circuits 17G and 17H via the capacitors 20 and 21, respectively.

  The sample hold circuits 18A to 18H operate on the basis of the sample hold signal SP generated by the timing generation circuit 6, and input during the period when the signal level of the sample hold signal SP rises. While the signal is output as it is, when the signal level of the sample hold signal SP falls, the input signal is sampled at the fall timing, and is sampled for a period until the signal level of the sample hold signal SP rises. An input signal is output.

  For the sample hold circuits 18A to 18H, the timing generation circuit 6 switches the light amount to the read power R, and then the light amount of the reflected light is settled after a predetermined period t determined by the characteristics of the optical disk 2, the write power W, etc. In FIG. 2, it is represented by output signals SA to SF of the light receiving surfaces A to F (FIG. 2 (B)), and at the timing immediately before switching from the read power R to the write power W after raising the signal level of the sample hold signal SP. The signal level of the sample hold signal SP is lowered.

As a result, the sample hold circuits 18A to 18H output the output signals of the amplifier circuits 17A to 17G as they are when the amount of reflected light is set (represented by the symbol S (FIG. 2C)), but from the read power R to the write power W. This output signal is sampled and held at the timing immediately before switching to, and the sampled input signal is output during the period until switching to the subsequent read power R.
The amplification circuit 22 mounted on the matrix board 16 subtracts and outputs the output signals of the first and second sample and hold circuits 18A and 18B, thereby generating a focus error signal FE.

At this time, during the period in which the signal level of the sample hold signal SP rises, the light reception results are output as they are from the sample hold circuits 18A to 18H, so that the amplifier circuit 22 has more focus than the conventional one. The error information can be output to the subsequent servo circuit 30, whereby the focus error signal FE with less error and less influence of noise can be output.
On the other hand, the amplifier circuits 23 and 24 mounted on the matrix board 16 subtract the output signals of the third and fourth sample and hold circuits 18C and 18D and the fifth and sixth sample and hold circuits 18E and 18F, respectively. The amplifier circuit 25 subtracts the output signals of the amplifier circuits 23 and 24, thereby generating a tracking error signal TE.

At this time, during the period in which the signal level of the sample hold signal SP rises, the light reception results are output as they are from the sample hold circuits 18A to 18H, so that the amplifier circuit 25 has more tracking than the conventional one. The error information can be output to the subsequent servo circuit 30, whereby a tracking error signal with less error and less influence of noise can be output.
Therefore, in the optical disk device 1, the accuracy of tracking control and focus control can be improved as compared with the conventional case, and the recording density can be further improved.

On the other hand, the amplifier circuit 26 subtracts and outputs the output signals of the seventh and eighth sample hold circuits 18G and 18H, thereby generating a wobble signal ATIP whose signal level changes according to the wobble of the pregroove. To do.
The pre-groove wobble is formed by frequency modulation at a center frequency of 22.05 [kHz], so that the light reception results from the sample hold circuits 18A to 18H during the period when the signal level of the sample hold signal SP rises. Is output as it is to generate the wobble signal ATIP, it is possible to reliably detect position information having a higher frequency.
Therefore, in the spectroscopic disk device 1, the position information of the light beam scanning position can be detected with high accuracy, and the recording density can be further improved accordingly.

By the way, the focus error signal has a feature that the frequency is lower (consisting of several [kHz]) than the tracking error signal and the wobble signal ATIP.
On the other hand, when forming a 3T-pit with the shortest recording wavelength, there is a feature that the period until the reflected light amount is set after switching to the lead power R is extremely short. There is also a possibility that noise is mixed into the cascading error signal FE.

  For this reason, in this embodiment, the timing generation circuit 6 uses the signal of the sample hold signal SP when the first and second sample hold circuits 18A and 18B for generating the focus error signal form a 3T period. The level is held at the L level, whereby the light reception result sampled immediately before is output to the amplifier circuit 22 as it is. As a result, with respect to the focus error signal FE, output of unnecessary high frequency components can be reduced, and mixing of noise and the like can be reduced.

  Thus, in the optical disk device 1, the accuracy of tracking control and the detection accuracy of position information can be improved by forming a period for directly outputting the light reception results input to the sample hold circuits 18A to 18H. By switching the period to be changed according to the size of the pitch, it is possible to obtain a light reception result at an optimal timing according to each servo signal, thereby further improving the accuracy of tracking and the like.

  That is, the servo circuit 30 drives the focus coil 9 and the tracking coil 10 based on the focus error signal FE and the tracking error signal TE, thereby performing the focus control and tracking control, while the spindle PLL circuit. 3 rotates the spindle motor 5 so that the center frequency of the wobble signal ATIP is 22.05 [kHz].

(2) Effects of the embodiment According to the above configuration, the servo circuit 30 and the amplification circuits 22 to 25 continue the light reception result as long as the amount of light beam is switched to read power and the amount of reflected light is stable. , And by outputting the light reception results sampled during other periods, more tracking error information and the like can be output to the servo circuit 30 and the amplification circuits 22 to 25 than in the prior art. 30. Amplifying circuits 22 to 25 can generate a tracking error signal, a wobble signal, and a focus error signal to generate a highly accurate signal, thereby improving the accuracy of tracking control and the like.

(3) Other Embodiments In the above-described embodiments, the output signals SA to SD of the light receiving element 12 are temporarily added by the amplifier circuits 17A to 17D, 17G, and 17H, and then the amplifier circuits 22 to 25 following the sample hold circuit. However, the present invention is not limited to this, and a matrix circuit that generates a tracking error signal, a focus error signal, and the like is described. It may be arranged at any location before and after the sample and hold circuit.

  Further, in the above-described embodiment, when forming a pitch with a period of 3T, for the focus error signal, the signal level of the sample hold signal is held at the L level, and the light reception result sampled immediately before is output to the amplifier circuit 22 as it is. However, the present invention is not limited to this, and this control may be applied to a sample-and-hold circuit assigned to a tracking error signal. In addition to this, the operation of the sample and hold circuit may be switched also when a pit having a period of 4T or the like is formed.

  Further, in the above-described embodiments, the case where desired information is recorded / reproduced on / from an optical disk having an information recording surface formed of an organic dye has been described. The present invention can be widely applied to an optical disk device that switches and records desired information.

1 is a block diagram illustrating an optical disk device according to an embodiment of the present invention. It is a signal waveform diagram for explanation of the operation. It is a block diagram with which it uses for description of a process of a light reception result. It is a signal waveform diagram with which it uses for description of operation | movement of the conventional optical disc apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical disc apparatus, 2 ... Optical disc, 8 ... Optical pick-up, 12, 13 ... Light receiving element, 9 ... Focus coil, 10 ... Tracking coil, 15A-15F, 15RF ... Head amplifier, 17A-17I, 22-26... Amplifier circuit, 18A-18... Sample hold circuit 18A.

Claims (2)

By switching the amount of light beam between the write power and the read power and irradiating a predetermined disk-shaped recording medium with the light beam, desired information is recorded on the disk-shaped recording medium by EFM modulation, or the above-mentioned In an optical disk device for reproducing EFM modulated information,
A light receiving signal output means for receiving reflected light of the light beam obtained from the disk-shaped recording medium by a plurality of light receiving surfaces and outputting a light receiving signal from each of the plurality of light receiving surfaces;
Provided respectively for generating Fuo Kas error signal and wobble signal corresponding to each of the light receiving signals output from said plurality of light receiving surfaces, in the period of the Ridopawa of the light receiving signal, sampling the received signal In the write power period , a plurality of sample and hold means for holding and outputting the light reception signal sampled in the read power period, and
Control means for performing focus control on the plurality of sample hold means based on the focus error signal generated by the first sample hold means provided for generating the focus error signal; With
The first sample hold means includes:
When the light reception signals output from the plurality of light receiving surfaces form three or four periods with respect to the reference period of the EFM modulation, the sampling is not performed during the lead power period, and the lead power period is not performed. with respect to the reference period of the previous value when the sampling period of the Ridopawa hold period of the write power output as the light receiving signal, the light receiving signals output from the plurality of light-receiving surface the EFM modulation for the KoTsuta values the sampling period of the Ridopawa when longer than the third period or the 4 cycle held in the period of the write power Te, and outputs it as a received signal, the Fuo Kas errors for performing the Fuokasu control An optical disk device characterized by generating a signal. By switching the amount of light beam between the write power and the read power and irradiating a predetermined disk-shaped recording medium with the light beam, desired information is recorded on the disk-shaped recording medium by EFM modulation, or the above-mentioned In an optical disk recording method for reproducing EFM modulated information,
The reflected light of the light beam obtained from the disk-shaped recording medium is received by a plurality of light receiving surfaces, and a focus error signal and a wobble signal are generated corresponding to the light receiving signals output from the plurality of light receiving surfaces, respectively. A plurality of sample and hold steps for sampling the light reception signal during the read power period of the light reception signal and holding and outputting the light reception signal sampled during the read power period during the write power period;
For the plurality of sample and hold steps , based on the focus error signal generated in the first sample and hold step provided for generating the focus error signal, the focus control includes a control step, and
The first sample and hold step includes:
When the light reception signals output from the plurality of light receiving surfaces form three or four periods with respect to the reference period of the EFM modulation, the sampling is not performed during the lead power period, and the lead power period is not performed. with respect to the reference period of the previous value when the sampling period of the Ridopawa hold period of the write power output as the light receiving signal, the light receiving signals output from the plurality of light-receiving surface the EFM modulation for the KoTsuta values the sampling period of the Ridopawa when longer than the third period or the 4 cycle held in the period of the write power Te, and outputs it as a received signal, the Fuo Kas errors for performing the Fuokasu control An optical disk recording method, characterized in that it is generated as a signal.

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