Servo control method and apparatus for optical storage media, and data reading / writing apparatus

Abstract

This application discloses a servo control method and apparatus for optical storage media, as well as a data read / write apparatus, relating to the field of optical storage technology. In this method, the servo laser position error is compensated by removing the reproduced portion of the position error between the irradiation position of the servo laser on a reference plane and the read insector using a compensation value of the high-frequency reproduced error corresponding to the read / write position in the optical storage medium, in order to reduce the current position error. Based on the reduced position error, the objective lens shared by the servo laser and the read / write laser is controlled to remove the compensated position error and improve the control accuracy of the tracking servo control of the servo laser.

Description

[Technical Field]

[0001] child The application relates to the field of optical storage technology, and more particularly to servo control methods and apparatus for optical storage media, as well as data reading / writing devices. [Background technology]

[0002] Optical storage media are widely used for storing cold data because they have the ability to preserve data for long periods. Examples of optical storage media include Blu-ray discs (BDs) and compact discs (CDs).

[0003] When a write operation is performed on an optical storage medium, the write laser and the servo laser are focused on the recording layer and servo layer of the optical storage medium, respectively, by using the same objective lens. Tracking servo control is then performed on the objective lens based on the error between the laser spot position of the servo laser and the ideal track position in the servo layer (i.e., the position error of the servo laser), so that the subsequent write laser is irradiated onto the ideal track of the recording layer as much as possible, so that the data is written to the ideal track as much as possible, and so that the written data can be arranged on the recording layer in the form of tracks.

[0004] Currently, the control accuracy of tracking servo control for servo lasers (e.g., red lasers) is approximately 18 nanometers (nm). However, the control accuracy of tracking servo control required by high-density optical storage media is typically higher than 18 nm. High-density optical storage media are optical storage media in which the number of tracks in the recording layer exceeds a threshold number; that is, optical storage media with a large number of tracks in the recording layer.

[0005] Let's take high-density Blu-ray discs as an example. Blu-ray disc writing lasers require tracking servo control accuracy of 9nm. It is clear that the current control accuracy of servo laser tracking servo control is far from meeting the requirements of Blu-ray disc writing lasers. When data is written to a Blu-ray disc, the poor control accuracy of the servo laser tracking servo control causes interference (i.e., track squeezing) between the newly written data track and adjacent already written data tracks in the recording layer. As a result, the newly written data overwrites the already written data on the adjacent data track, and the already written data on the adjacent data track is lost. Therefore, there is an urgent need for a servo control method for optical storage media to improve the control accuracy of servo laser tracking servo control. [Overview of the Initiative]

[0006] Embodiments of this application provide a servo control method and apparatus for optical storage media, as well as a data read / write device, for improving the control accuracy of tracking servo control of a servo laser. The technical solution is as follows:

[0007] According to a first aspect, a servo control method for an optical storage medium is provided. The method includes at least the following steps: first, acquiring a compensation value corresponding to a read / write position in the optical storage medium; second, compensating for a position error of the servo laser of a data read / write device based on the acquired compensation value; and third, controlling the objective lens of the data read / write device based on the compensated position error to perform data read / write at the position in the optical storage medium.

[0008] In this method, the servo laser's position error is compensated by using a compensation value corresponding to the read / write position on the storage medium to reduce the current position error. Based on the reduced position error, the data read / write device is controlled using an objective lens to eliminate the compensated position error when reading / writing data. This improves the control accuracy of the servo laser's tracking servo control.

[0009] In one possible implementation, the read / write location is on a track close to the center of the optical storage medium.

[0010] Based on the aforementioned possible implementations, when data is read from or written to a track near the center of the optical storage medium, the servo laser position error is reduced by using a compensation value corresponding to the read / write position on the track near the center. As a result, under servo laser position guidance, data can be written to the read / write position on the track near the center as precisely as possible, reducing the track width of the data track written to the read / write position and avoiding writing to adjacent data tracks. Thus, data tracks written to the track near the center do not intersect.

[0011] In one possible implementation, the read / write location lies on a portion of the track within the optical storage medium.

[0012] Based on the aforementioned possible implementations, when data is read or written on tracks near the center of the optical storage medium, the servo laser position error is reduced by using a compensation value corresponding to the read / write positions on the aforementioned partial tracks. As a result, under servo laser position guidance, data can be written to the read / write positions on the aforementioned partial tracks as much as possible, reducing the track width of the data tracks written to the read / write positions and avoiding writing to adjacent data tracks. Thus, the data tracks written to the aforementioned partial tracks do not intersect.

[0013] In one possible implementation, before obtaining a compensation value corresponding to a read / write position on an optical storage medium, the method further includes the following step, that is, detecting a plurality of positions on the optical storage medium and obtaining compensation values for the plurality of positions.

[0014] Based on the aforementioned possible implementation, a plurality of positions on the optical storage medium are detected and compensation values for the plurality of positions are obtained. As a result, these obtained compensation values are applicable to the optical storage medium. When data is subsequently read from / to a read / write position corresponding to the plurality of positions on the optical storage medium, the position error of the corresponding position can be accurately compensated by using an appropriate compensation value, thereby reducing the position error of the corresponding position. This improves the control accuracy of the tracking servo control of the optical storage medium.

[0015] In one possible implementation, the process of detecting a plurality of positions on the optical storage medium and obtaining compensation values for the plurality of positions includes at least the following steps: first, detecting a plurality of positions on the optical storage medium and obtaining a plurality of position errors for each position of the plurality of positions; then, determining a reproduction error for each position based on the plurality of position errors of each position, where the reproduction error refers to the reproducible part of the position errors; and then, determining a compensation value for each position based on the reproduction error of each position.

[0016] Based on the aforementioned possible implementation, a high-frequency reproduction error can be extracted from the reproduction error of each position. By using the high-frequency reproduction error of each position as the compensation for each position, when the position error of the servo laser at each position is compensated based on the compensation value of each position, the high-frequency reproduction error within the position error of each position can be removed, and the vibration amplitude of the position error in the high-frequency domain can be reduced. Therefore, the control accuracy of the servo laser control can be improved, and the intersection of the data tracks to be written can be avoided.

[0017] In one possible implementation, the process of determining the compensation value at each position based on the reproduction error at each position includes the following steps: first, performing a frequency domain conversion on the reproduction error at each position to obtain a plurality of frequency domain reproduction errors at each position; and then, determining the compensation value at each position based on the high-frequency reproduction errors within the plurality of frequency domain reproduction errors at each position. The plurality of frequency domain reproduction errors correspond to different frequencies, and the high-frequency reproduction errors are the frequency domain reproduction errors corresponding to frequencies above a frequency threshold.

[0018] Based on the above-mentioned possible implementation, the high-frequency reproduction errors can be extracted from the reproduction errors at each position, and by using the high-frequency reproduction errors at each position as the compensation for each position, when the position error of the servo laser at each position is compensated based on the compensation value at each position, the high-frequency reproduction errors within the position error at each position can be removed, the vibration amplitude of the position error in the high-frequency domain can be reduced, and the control accuracy of the tracking servo control can be improved.

[0019] In one possible implementation, before detecting a plurality of positions on the optical storage medium and obtaining the compensation values for the plurality of positions, the method further includes the following steps: obtaining the transfer function of the tracking control circuit of the servo laser in the data read / write device; and obtaining the compensation values for the plurality of positions based on the transfer function and the detection results of detecting the plurality of positions on the optical storage medium.

[0020] Based on the above-mentioned possible implementation, the transfer function of the tracking control circuit of the servo laser in the data read / write device is obtained. As a result, the compensation value obtained based on the transfer function is more accurate. By compensating the position error of the tracking control circuit using the accurate compensation value, the compensation effect of the position error can be enhanced, and the control accuracy of the tracking servo control can be improved.

[0021] In one possible implementation, the method further includes the following step: if the written data is overwritten during the data read / write process, then multiple locations in the optical storage medium are detected again and the compensation values ​​for those locations are updated.

[0022] Based on the aforementioned possible implementations, multiple locations are re-detected, new compensation values ​​are obtained for each location, and data is rewritten to the read / write locations based on the compensation value corresponding to each location, thereby obtaining a new data track and avoiding the new data track intersecting with adjacent data tracks.

[0023] According to a second aspect, a servo control device for an optical storage medium is provided and is configured to perform the method described above for the servo control device for an optical storage medium. Specifically, the servo control device includes a functional module configured to perform the method provided in the first aspect or an optional configuration of the first aspect.

[0024] According to a third aspect, a data read / write device for an optical storage medium is provided. The data read / write device includes a processor, which is configured to execute program code, so that the data read / write device performs the method provided in the first aspect or an optional configuration of the first aspect.

[0025] According to a fourth aspect, a compensator for use in a data read / write device is provided. The data read / write device is configured to read / write data to / from an optical storage medium. The compensator includes a processor, which is configured to execute program code, so that the compensator performs the method provided in the first aspect or an optional scheme of the first aspect.

[0026] According to the fifth aspect, a computer-readable storage medium is provided. The storage medium stores at least one program code, and the at least one program code is read by the processor of a data read / write device so that the data read / write device performs a method provided in the first aspect or an optional method of the first aspect.

[0027] According to the sixth aspect, a computer program product is provided. The computer program product includes at least one program code, and when the at least one program code is executed by a processor in a data read / write device, the data read / write device is enabled to perform a method provided in the first aspect or an optional implementation of the first aspect.

[0028] Based on the implementations provided in the aforementioned embodiments, these implementations can be further combined to provide even more implementations in this application. [Brief explanation of the drawing]

[0029] [Figure 1] This is a cross-sectional view of an optical storage medium according to one embodiment of this application. [Figure 2] This is a diagram of a data read / write device for an optical storage medium according to one embodiment of this application. [Figure 3] This is a diagram of an OPU according to one embodiment of this application. [Figure 4] This is a flowchart of a method for obtaining a compensation value for the position error of a servo laser according to one embodiment of this application. [Figure 5] This is a diagram of a position error compensation control loop according to one embodiment of this application. [Figure 6] This figure shows the amplitude-frequency characteristic curve of the transfer function of a tracking control circuit according to one embodiment of this application. [Figure 7] This is a diagram of the irradiation track of a servo laser according to one embodiment of this application. [Figure 8] This figure shows the local position error of the same inner ring track according to one embodiment of this application. [Figure 9] This is a flowchart of a servo control method for an optical storage medium according to one embodiment of this application. [Figure 10] This is a diagram of the control logic for tracking servo control according to one embodiment of this application. [Figure 11] This is a diagram showing a data writing process for an optical storage medium according to one embodiment of this application. [Figure 12] This figure shows a comparison of positional errors between servo lasers according to one embodiment of this application. [Figure 13] This is a diagram of a servo control device for an optical storage medium according to one embodiment of this application. [Figure 14] This is a diagram showing the configuration of a compensator according to one embodiment of this application. [Modes for carrying out the invention]

[0030] To further clarify the purpose, technical solution, and advantages of this application, the implementation of this application will be described in detail below with reference to the attached drawings.

[0031] This application relates to a data read / write device. The data read / write device is configured to read data from and / or write data to (in other words, read / write data) an optical storage medium, into which the data read / write device is provided, and the optical storage medium is a recording medium that records and reads data through laser irradiation. The optical storage medium is, for example, a BD, CD, or digital versatile disc (DVD). The type of optical storage medium 100 is not limited to the embodiments of this application.

[0032] For example, Figure 1 is a cross-sectional view of an optical storage medium according to one embodiment of this application. The optical recording medium 100 includes, in order, a cover layer 11, a recording layer 12, a reflective layer 13, and a lead-in layer 14, where s is an integer of 1 or more. The value of s is not limited to this embodiment of this application. The cover layer 11 is configured to cover each recording layer 12.

[0033] If multiple recording layers 12 exist, in order to distinguish between them, the recording layers are numbered sequentially from L1 to Ls based on their distance from the lead-in layer 14, where L1 is the recording layer 12 closest to the lead-in layer 14, and Ls is the recording layer 12 furthest from the lead-in layer 14.

[0034] The recording layer 12 is configured to record data, and the method of recording data is as follows: When a laser is shone onto the recording layer 12, a physical or chemical change occurs in the medium constituting the surface of the recording layer 12, and the state of the medium changes. The recorded data is represented by the state of the medium. For example, the medium is a phase-change material. When a laser is shone onto the recording layer 12, the laser converts a portion of the phase-change material from an amorphous state to a crystalline state. The crystalline phase-change material can represent and record one type of data, for example, it can represent data "1". Zones in the recording layer 12 where the phase-change material is not distributed can represent other types of data, for example, it can represent data "0". Certainly, instead, the crystalline phase-change material may represent data "0", or zones in the recording layer 12 where the phase-change material is not distributed may represent data "1".

[0035] For example, recording layer 12 is lead-in ( lead-inThe optical storage medium includes a lead-in zone and a data zone. The lead-in zone is used to store metadata for the optical storage medium, and the metadata includes relevant parameters for the layers of the optical storage medium 100. The data zone is used to store data. The data zone contains r tracks, where r is an integer greater than 1, and the value of r may or may not be the same for different optical storage media. The value of r is not limited to this embodiment of this application.

[0036] r tracks are arranged in a spiral configuration in the recording layer 12. By irradiating the tracks with a laser, data is recorded (in other words, written) along the tracks to the recording layer, and as a result, the data is arranged in the recording layer 12 in the form of tracks. When data is written to the tracks, the laser irradiation position is not necessarily on the tracks. Consequently, the tracks formed by the written data are different from the tracks in the recording layer. For ease of explanation, the tracks formed by the written data are referred to as data tracks, and the tracks in the recording layer are referred to as recording tracks or virtual tracks. In some other embodiments, the recording layer 12 does not have recording tracks, and the control unit reads / writes data in the recording layer 12 based on the parameters of the recording tracks provided by the metadata of the optical storage medium 100. It should be understood that a larger r indicates a smaller inter-track distance (in other words, track spacing), a higher track density, and a larger capacity of the recording layer 12. Conversely, a smaller r indicates a larger track spacing, a lower track density, and a smaller capacity of the recording layer 12. To distinguish between tracks, the tracks are numbered sequentially from T1 to Tr based on their radial distance from the center of the optical recording medium 100, where T1 is the track closest to the center, in other words, the 1st track, and Tr is the track furthest from the center, in other words, the rth track.

[0037] Each track contains M sectors, where M is an integer greater than 1. Data is recorded on the tracks in units of sectors, and the distribution of sectors may or may not be the same across different optical storage media. The value of M is not limited to this embodiment of this application.

[0038] A lead-in track 141 is provided on the surface of the lead-in layer 14, and the lead-in track 141 is sometimes called a lead-in groove. The lead-in track 141 is a position configured for the lead-in device to record read / write positions. For example, the lead-in track 141 is a pit string formed of pits and lands. Read / write positions are recorded by using a combination of pits and lands of a certain length. Another example is that the lead-in track 141 is a wobble structure formed by grooves. Read / write positions are recorded by using a wobble structure with a certain wobble period.

[0039] The lead-in layer 14 contains r lead-in tracks 141, and the arrangement of the r lead-in tracks 141 is the same as the arrangement of tracks in the recording layer 12. To distinguish between the lead-in tracks 141, the lead-in tracks 141 are sequentially numbered T based on their radial distance from the center of the optical recording medium 100. (ref,1) From T (ref,r) Number them up to here, T (ref,1) This is the lead-in track 141 closest to the center, in other words, the first lead-in track 141, T (ref,r) This is the track furthest from the center, in other words, the r-th lead-in track 141.

[0040] Correspondingly, the lead-in track 141 contains M sectors. For ease of explanation, sectors in the lead-in track 141 are referred to as lead-in sectors, and sectors of tracks in the recording layer 12 are referred to as recording sectors. Each lead-in sector corresponds to each recording layer 12Corresponding to one recording sector in the recording layer, the position of each lead-in sector in the first layer of the lead-in layer is the recording layer 12 This is the location of the corresponding recording sector in the recording layer. The arrangement of lead-in track 141 is the recording layer 12 This is the same as the truck arrangement method in the diagram. 1 As shown, two laser beams are shone onto the storage medium using the same objective lens, with one laser beam shone onto the lead-in track 141 and the other laser beam shone onto the recording layer. 12 This guides the system to read / write data on the corresponding track.

[0041] To distinguish between the laser acting on the recording layer 12 and the laser acting on the lead-in layer 14, the laser acting on the recording layer 12 is called the read / write laser, and the read / write laser is used to read data on the tracks in the recording layer 12 or write data (in other words, to read / write data), while the laser acting on the lead-in layer 14 is called the servo laser. The read / write laser and the servo laser have different wavelengths. For example, the read / write laser is a blue laser, and the servo laser is a red laser. For ease of explanation, the wavelength of the read / write laser is called the first wavelength, and the wavelength of the servo laser is called the second wavelength.

[0042] A reflective layer 13 is placed between the lead-in layer 14 and the recording layer L1 to allow the servo laser to penetrate the recording layer 12 and irradiate the lead-in layer 14, while preventing the read / write laser from irradiating the lead-in layer 14. The reflective layer 13 has the function of reflecting the first wavelength laser and transmitting the second wavelength laser. Therefore, after the read / write laser is irradiated onto the reflective layer 13, the reflective layer 13 reflects the read / write laser, preventing it from irradiating the lead-in layer 14. After the servo laser is irradiated onto the reflective layer 13, the reflective layer 13 transmits the servo laser, and as a result, the servo laser is irradiated onto the lead-in track 141 of the lead-in layer 14, leading the read / write laser to read / write data in the recording layer 12. Based on this, the surface of the lead-in track 141 is referred to as the reference (Ref) surface or servo surface.

[0043] Next, referring to Figure 2, the principle of reading / writing data on an optical storage medium by a data reading / writing device will be explained in detail below.

[0044] Figure 2 shows a data read / write device for an optical storage medium according to one embodiment of this application. As shown in Figure 2, the data read / write device 200 includes a control unit 21, an optical processing unit (OPU) 22, a rotary table 23, and a compensator 24. The rotary table 23 is configured to hold the optical storage medium 100. The control unit 21 controls the rotary table 23 to rotate, so that the optical storage medium 100 rotates with the rotary table 23. The control unit 21, OPU 22, and compensator 24 are located within the laser drive circuit 203 in Figure 1.

[0045] During the rotation process of the optical storage medium 100, the control unit 21 reads / writes data to / from the optical storage medium 100. For example, the control unit 21 controls the OPU 22 to emit a read / write laser and a servo laser onto the optical recording medium 100, and under the guidance of the servo laser, irradiates the recording layer Lh of the optical recording medium 100 with the read / write laser, thereby reading / writing data to the recording layer Lh. The recording layer Lh is the h-th recording layer 12 of the optical recording medium 100, where h is greater than or equal to 1 and less than or equal to s.

[0046] For example, Figure 3 is a diagram of the configuration of an OPU according to one embodiment of this application. The process of reading data to and writing data to the optical recording medium 100 is described below.

[0047] As shown in Figure 3, a read / write optical path and a servo optical path are arranged within the OPU 22. The read / write optical path is configured to radiate a read / write laser onto the optical storage medium 100 and transmit the reflected read / write laser. The read / write laser is either a read laser or a write laser; the write laser is used to write data to the optical storage medium 100, and the read laser is used to read data from the optical storage medium 100. The reflected read / write laser is the read / write laser reflected on the optical storage medium 100. The reflected read laser is either a read laser or a write laser; the reflected read laser is the read laser reflected on the optical storage medium 100, and the reflected write laser is the write laser reflected on the optical storage medium 100.

[0048] Using an example in which a read / write laser is emitted onto an optical storage medium 100, the process of transmitting the read / write laser over a read / write optical path will be explained below.

[0049] The control unit 21 controls the first laser emitter a1 to emit a read / write laser to the first beam splitter a2, and the first beam splitter a2However, the read / write laser is transmitted to the compensating mirror group a3, and the compensating mirror group a3 performs focusing compensation on the transmitted read / write laser based on the focus servo control of the control unit 21. As a result, the read / write laser can be irradiated onto the recording layer Lh in the optical storage medium 100, and the refractive index mismatch problem of the read / write laser can be corrected. The corrected read / write laser is radiated to the dichroic mirror c1. The dichroic mirror c1 transmits the incident read / write laser to the objective lens c2. The objective lens c2 focuses the incident read / write laser and irradiates the read / write laser onto the recording layer Lh in the optical recording medium 100, forming a laser spot of the read / write laser on the recording layer Lh. The recording layer Lh reflects the read / write laser, and the reflected read / write laser is obtained. After being reflected by the objective lens c2, the reflected read / write laser is transmitted to the first beam splitter a2 by sequentially passing through the objective lens c2, the dichroic mirror c1, and the compensating mirror group a3. The first beam splitter a2 reflects the reflected read / write laser towards the first photodetector integrated circuit (PDIC) a4, and the first photodetector integrated circuit a4 detects the reflected read / write laser to obtain a photodetector signal of the read / write laser. This photodetector signal carries positional information of the laser spot of the read / write laser, indicating the irradiation position of the read / write laser in the recording layer Lh.

[0050] As shown in Figure 3, the servo optical path is configured to radiate a servo laser onto the optical storage medium 100 and to transmit the reflected servo laser from the optical storage medium 100 (i.e., the servo-reflected laser). Using an example in which the servo laser is radiated onto the optical storage medium 100, the process of transmitting the servo laser on the servo optical path will be described below.

[0051] The control unit 21 controls the second laser emitter b1 to emit a servo laser to the second beam splitter b2, the second beam splitter b2 emits the servo laser to the dichroic mirror c1, and the dichroic mirror c1 transmits the incident servo laser to the objective lens c2. The objective lens c2 focuses the incident servo laser and irradiates the servo laser onto the reference surface of the optical recording medium 100, forming a servo laser spot on the reference surface. The reference surface reflects the servo laser to obtain a servo-reflected laser, which is reflected back to the objective lens c2, and then transmitted through the objective lens c2 to the second beam splitter b2. A second beam splitter b2 reflects the servo-reflected laser toward a second photodetector integrated circuit b3, which is configured to detect the servo-reflected laser and obtain a photodetector signal of the servo laser. This photodetector signal carries positional information of the servo laser spot, indicating the irradiation position of the servo laser on a reference plane.

[0052] The first beam splitter a2 and the second beam splitter b2 can be polarization beam splitters (PBS) and are configured to transmit or reflect the incident laser based on the polarization direction of the incident laser. Both the first laser emitter a1 and the second laser emitter b1 can be laser diodes (LDs). The read / write laser emitted by the first laser emitter a1 may be a blue laser. The servo laser emitted by the second laser emitter b1 may be a red laser. Figure 3 is illustrated by using an example in which the read / write optical path includes one first laser emitter a1 and the first laser emitter a1 emits either a write laser or a read laser. In some other embodiments, the read / write optical path includes two first laser emitters a1, each configured to emit a write laser and a read laser, respectively. The number of first laser emitters a1 on the read / write optical path is not limited to this embodiment of this application. In some other embodiments, the first laser emitters a1 may also be replaced by a laser emitter array that emits a write laser array or a read laser array, so that multiple data can be stored in or read from the optical storage medium 200 at once, thereby improving the data read / write efficiency of the data read / write device 200. The write laser array includes multiple write lasers, and the read laser array includes multiple read lasers.

[0053] Figure 3 shows an example where the read / write optical path and the servo optical path share some photoelectric elements (e.g., a dichroic mirror c1 and an objective lens c2). In this case, the read / write laser and the servo laser are coaxial. In some other embodiments, the read / write optical path and the servo optical path are separate optical paths and do not share photoelectric elements.

[0054] In the data reading / writing process, the control unit 21 acquires the photodetector signal of the servo laser from the second photodetector integrated circuit b3, extracts position information of the servo laser from the photodetector signal, and generates a focus position error and a tracking position error of the servo laser based on this position information. The focus position error refers to the distance between the laser spot position of the servo laser and the reference plane. The tracking position error is the radial distance between the laser spot position of the servo laser and the target position, where the target position is the position on the reference plane corresponding to the reading / writing position of the recording layer Lh.

[0055] The control unit 21 generates a focus servo signal based on the focus position error and a focus control algorithm (e.g., an offline invariant time control algorithm), and based on the focus servo signal, performs focus servo control on the objective lens c2 shared by the read / write laser and the servo laser, expecting that the servo laser can be irradiated onto a reference plane. The focus servo signal is used to eliminate the focus position error, and the process of performing focus servo control on the objective lens c2 can be as follows: The control unit 21 is connected to the objective lens c2 using a torquer, and the control unit 21 controls the torquer based on the focus servo signal to drive the objective lens c2 to move in the focus direction of the optical storage medium 100 so that the servo laser can be irradiated onto the reference plane.

[0056] The control unit 21 generates a tracking servo signal based on the tracking position error and the tracking control algorithm, tracking Based on the servo signal, the servo laser is expected to be directed at the target position on the reference plane, and the objective lens c2 shared by the read / write laser and the servo laser is used. trackingServo control is performed. The tracking servo signal is used to eliminate tracking position errors, and the process of performing tracking servo control on the objective lens c2 can be as follows: The control unit 21 controls the torquer based on the tracking servo signal to drive the objective lens c2 to move radially across the optical storage medium 100 so that the servo laser can be irradiated onto a target position on the reference plane.

[0057] However, the control accuracy of the tracking control algorithms used in related technologies cannot meet the control accuracy requirements for the Blu-ray disc read / write laser for tracking servo control. When data is written to a Blu-ray disc, it is easy for newly written data tracks to intersect with adjacent data tracks by the recording layer. We will use a position control method based on an adjacent track servo system (ATS) in related technologies as an example. In ATS technology, both the laser used for adjacent track servoing (referred to as the ATS laser) and the write laser are irradiated onto the recording layer to be written, and the tracking position error of the ATS laser is compensated for the tracking position error of the servo laser to generate a tracking servo signal. Based on this tracking servo signal, tracking servo control is performed on the objective lens so that the laser spot of the laser used for adjacent track servoing (referred to as the ATS laser) follows the laser spot of the write laser on the recording track to be written in the preceding recording track of the recording track to be written.

[0058] The tracking position error of the ATS laser is the radial distance between the laser spot of the ATS laser and the laser spot of the writing laser on the recording layer being written to. The method for compensating the tracking position error of the ATS laser for the tracking position error of the servo laser is as follows: The tracking position error of the ATS laser is integrated using an integrator, and the integrated result is added to the tracking position error of the servo laser to compensate for the servo laser's tracking position error. The compensated tracking position error is provided to the tracking control circuit of the servo laser, and the integrated result is filtered using a filter to obtain the filtered result. This filter is used as a feedforward controller for the tracking control circuit of the servo laser. Based on the filtered result, feedforward control is performed on the output result of the tracking control circuit to obtain the tracking servo signal.

[0059] However, in the aforementioned compensation method, the integrator has characteristics such as long computation time and poor flexibility, so high-speed positioning at arbitrary positions is not performed in the tracking servo control process. The integrator easily causes a continuous divergence phenomenon in the response of the tracking control circuit, resulting in low control accuracy of the tracking servo control and easily causing the data tracks to cross when the data is written to the optical storage medium. In addition, the filter is used as a feedforward controller, and the filter reduces the phase margin of the tracking control circuit. When the data is written to the optical storage medium, the low phase margin of the tracking control circuit also causes the data tracks to cross when the data is written.

[0060] In view of this, this application proposes a novel position error compensation scheme for compensating for tracking position errors of a servo laser in a read / write process. The compensation scheme is performed by a compensator within the data read / write device (e.g., compensator 24 in Figure 2). The compensator is integrated into the control unit of the data read / write device, or is located within the data read / write device independently of the control unit.

[0061] The compensator first detects multiple positions on the optical storage medium on the data read / write device and obtains compensation values ​​for these positions in order to later compensate for positional errors of the servo laser at positions on a reference plane. These multiple positions are multiple lead insectors, i.e., multiple lead-in positions, on the reference plane of the optical storage medium. The distribution of lead insectors in different optical storage mediums may or may not be different. Based on this, when any optical storage medium is taken into the data read / write device, or when the data read / write device starts the optical storage medium, the compensator performs the step of detecting multiple positions on the optical storage medium and obtaining compensation values ​​for these positions so that these compensation values ​​are applicable to the optical storage medium. Certainly, this step does not have to be performed when the optical storage medium is taken into the data read / write device or when the data read / write device starts the optical storage medium, but may be performed before or at the time the optical storage medium reads / writes data. The opportunities to perform this step are not limited to the embodiments of this application. In some other embodiments, the compensator may not perform this step if it has pre-stored compensation values ​​for multiple positions in at least one optical storage medium. When any one of the at least one optical storage mediums reads or writes data, the compensator uses the stored compensation values ​​for multiple positions in any one of the optical storage mediums to compensate for positional errors of the servo laser in the data read / write process.

[0062] The process for detecting multiple locations on the optical storage medium on the data read / write device and obtaining compensation values ​​for those locations is similar for different optical storage media. The process is described in detail below using an arbitrary optical storage medium as an example. For the process of obtaining compensation values ​​for multiple locations on other optical storage media, please refer to the following description.

[0063] For example, Figure 4 is a flowchart of a method for obtaining a compensation value for the position error of a servo laser according to one embodiment of this application. The method is performed by a compensator in a data read / write device.

[0064] 401: The compensator obtains the transfer function of the tracking control circuit of the servo laser in the data read / write device.

[0065] The data read / write device is any of the data read / write devices described above. The tracking control circuit is a loop used for tracking servo control of the servo laser within the data read / write device. The transfer function of the tracking servo control shows the response of the output parameters of the tracking control circuit to the input parameters.

[0066] Figure 5 shows a position error compensation control loop according to one embodiment of this application. The control loop shown in Figure 5 using solid lines is as follows: In the tracking control circuit, an addition / subtraction unit G is configured to perform subtraction operations on input parameters and output parameters; a tracking servo controller C is a module within the control unit of the data read / write device configured to perform tracking servo control on the servo laser; and a torquer P is a torquer configured to control the movement of the objective lens. The input and output parameters of the tracking control circuit are the target position and the measured position, respectively. The target position is the read insector corresponding to the position to be read / written in the optical storage medium, in other words, the target irradiation position of the servo laser. The measured position is the detected laser spot position of the servo laser. The transfer function of the tracking control circuit is:

number

[0067] The mechanical properties of the control elements (e.g., C and P) of different tracking control circuits may be the same or different. When the mechanical properties differ, the amplitude of the transfer function of the different tracking control circuits will differ. For example, Figure 6 shows the amplitude-frequency characteristic curve of the transfer function of a tracking control circuit according to one embodiment of this application. The amplitude-frequency curve 601 shows the amplitude change of the transfer function at different frequencies, and the phase-frequency curve 602 shows the phase change of the transfer function at different frequencies. When the control elements are different, the amplitude of the transfer function of the tracking control circuit may differ by as much as 1 dB to 2 dB.

[0068] Based on this, when the compensator provided in this application is used in a data read / write device, the compensator uses a transfer function in the subsequent calculation of the compensation value in the data read / write device. tracking The transfer function of the servo loop is obtained. The compensator obtains the transfer function using either Method 1 or Method 2 below.

[0069] Method 1: The compensator tests the transfer function of the tracking control circuit to obtain the transfer function.

[0070] For example, the compensator tests the transfer function of each control element of the tracking control circuit and generates the transfer function of the tracking control circuit based on the tested transfer data of each control element according to the above equation for the transfer function of the tracking control circuit. The method of testing the transfer function is not limited to this embodiment of this application.

[0071] By testing the transfer function of the tracking control circuit, its accurate transfer function can be obtained. Compensation values ​​calculated using this accurate transfer function are more precise. Compensating for the position error of the tracking control circuit using these accurate compensation values ​​improves the effectiveness of position error compensation, thereby enhancing the control accuracy of the tracking servo control.

[0072] Method 2: If the description file of the data read / write device contains the transfer function of the tracking control circuit, the compensator obtains the transfer function from the description file. If the description file of the data read / write device does not contain the transfer function of the tracking control circuit, the function is obtained using Method 1.

[0073] Description files are used to describe data read / write devices, for example, to describe the operating principles of each control module within the data read / write device.

[0074] It should be understood that the transfer function of the tracking control circuit is used to calculate the compensation value, and the compensator may acquire the transfer function before calculating the compensation value (e.g., step 404), for example, before the data read / write device leaves the factory. Alternatively, the transfer function may be acquired when the compensation value is calculated. The opportunity to acquire the transfer function is not limited here to this embodiment of this application. Certainly, if the compensator has the transfer function, it does not need to acquire it by performing step 401. For example, if the compensator has pre-stored the transfer function of the tracking control circuit of at least one type of data read / write device, the compensator does not need to perform step 401 and only needs to use the transfer function of the tracking control circuit of the target type of data read / write device when calculating the compensation value. The target type is the type of data read / write device in which the compensator is located. Thus, step 401 is an optional step and is represented correspondingly by a dashed box in Figure 4.

[0075] 402: The compensator detects multiple positions on the optical storage medium on the data read / write device and obtains multiple positional errors for each of those positions.

[0076] The optical storage medium is any optical storage medium that is loaded into a data read / write device, such as a Blu-ray disc. The multiple positions are multiple read insectors detected on the reference plane of the optical storage medium, in other words, the ideal irradiation positions of the servo laser in the detection process. The multiple positional errors of the arbitrary position are multiple tracking positional errors of the servo laser irradiated to the arbitrary position, and the tracking positional error is the radial distance between the laser spot position of the servo laser and the arbitrary position.

[0077] Multiple locations are located on at least one lead-in track detected on the reference plane, which may be all of the lead-in tracks on the reference plane or a portion of the lead-in tracks on the reference plane. Since the process for detecting locations on each lead-in track is the same, step 402 will be described here using the detection of locations on a portion of the lead-in tracks as an example. For detecting locations on all lead-in tracks, please refer to the process for detecting locations on a portion of the lead-in tracks.

[0078] For example, multiple positions are located on a portion of the lead-in tracks on the reference plane. For any layer of the reference plane and recording layer, the compensator divides r tracks in the arbitrary layer into p inner ring tracks and q outer ring tracks, where p + q = r. The inner ring tracks are tracks closer to the center of the arbitrary layer, and the outer ring tracks are tracks further from the center of the arbitrary layer. For example, the compensator uses tracks whose radial distance from the center of the arbitrary layer is less than or equal to a first distance as inner ring tracks, and tracks whose radial distance from the center of the arbitrary layer is greater than the first distance as outer ring tracks. Optionally, the first distance is the eccentricity distance of the optical storage medium in the rotation process. For example, the value of the first distance is in the range of 0.3 nm to 1 nm. When the track width is 160 nm and the value of the first distance is 0.3 nm, the first to 500th tracks in any layer are all inner ring tracks, and when the value of the first distance is 1 nm, the first to 2000th tracks in any layer are all inner ring tracks. In some other embodiments, the first distance is not an eccentricity distance, but a distance determined based on the eccentricity distance or other factors, or the first distance is independent of the eccentricity distance. Herein, the range and method of taking the value of the first distance are not limited to this embodiment of the application, in other words, the number of inner ring tracks is not limited.

[0079] After determining p inner ring tracks, the compensator uses the p inner ring tracks on the reference plane as lead-in tracks to be detected, detects multiple positions on the p inner ring tracks, and obtains multiple positional errors for each of those positions.

[0080] Since the method for detecting each position error at each position is the same, for the sake of simplicity, the process for detecting one position error at each position on the p inner ring tracks will be described below, and for detecting other position errors at each position, please refer to that process.

[0081] In one possible implementation, multiple positions on p inner ring tracks on a reference plane are detected by performing the following steps 421 to 424 to obtain a position error of one of the multiple positions.

[0082] Step 421: The compensator controls the rotary table of the data read / write device, which in turn drives the rotary table to rotate the optical storage medium.

[0083] Step 422: The compensator controls the second laser emitter in the data read / write device to emit a servo laser onto the optical storage medium.

[0084] During the rotation process of the optical storage medium, a compensator controls a second laser emitter to continuously emit a servo laser so that the servo laser illuminates a reference surface of the optical storage medium through a servo optical path in the data read / write device, and the compensator controls the objective lens to emit the servo laser onto a lead-in track to be detected on the reference surface. As the optical storage medium rotates, it completes one revolution, and the servo laser completes scanning the lead-in track. During this time, a servo-reflected laser generated based on the servo laser on the reference surface is transmitted along the servo optical path to a second cylindrical lens in the servo optical path, and a second photodetector integrated circuit in the data read / write device detects multiple positions of the servo laser on the lead-in track based on the servo-reflected laser on the second cylindrical lens to obtain a photodetector signal of the servo laser, which carries information about the laser spot position of the servo laser as the lead-in track was scanned.

[0085] Step 423: During the rotation process of the optical storage medium, the compensator controls the objective lens in the data read / write device so that the servo laser moves radially across the optical storage medium.

[0086] An example of a plurality of positions on p inner ring tracks is used. In the order from the inner side to the outer side or in the order from the outer side to the inner side, the optical storage medium makes one full rotation, the servo laser completes scanning of the first lead-in track, and the compensator controls the objective lens in the data read / write device based on the track pitch so that the irradiation position of the servo laser jumps from the first lead-in track to the second lead-in track until the servo laser completes scanning of the p inner ring tracks. The first lead-in track is any one of the p inner ring tracks currently irradiated by the servo laser, and the second lead-in track is the inner ring track adjacent to the first lead-in track among the p inner ring tracks. When the objective lens is adjusted in the order from the inner side to the outer side, if the first lead-in track is T within the lead-in track of the p inner ring tracks (ref,z) then the second lead-in track is T within the lead-in track of the p inner ring tracks (ref,z+1) When the objective lens is adjusted in the order from the outer side to the inner side, if the first lead-in track is T within the lead-in track of the p inner ring tracks (ref,z) then the second lead-in track is T within the lead-in track of the p inner ring tracks (ref,z-1) where T (ref,z) refers to the z-th lead-in track of the reference Ref plane, and z is 1 or more and p or less.

[0087] Step 424: The compensator acquires the photodetector signal of the servo laser from the second photodetector integrated circuit in the data read / write device, and based on the photodetector signal of the servo laser, acquires a position error of one of the plurality of positions on the p inner ring tracks.

[0088] Each time the optical storage medium rotates once, the resulting photodetector signal carries information about the laser spot position of the servo laser when a certain lead-in track has been scanned. In step 423, the objective lens controls the servo laser to jump between lead-in tracks. Correspondingly, after the optical storage medium has rotated p times, the photodetector signal carries information about the laser spot position of the servo laser when p inner ring tracks have been scanned.

[0089] Assuming each inner ring track has M lead insectors, the compensator samples the photodetector signal obtained through p rotations to acquire p × M position information of the servo laser, each position information corresponding to one lead insector, and each position information indicates the laser spot position of the servo laser illuminating the corresponding lead insector. The position error of each lead insector is obtained based on the position indicated by each position information of the servo laser and the corresponding lead insector, and the position error of any lead insector is the radial distance between the position indicated by the corresponding position information of the servo laser and the arbitrary lead insector, in other words, one tracking position error of the servo laser.

[0090] Therefore, through the process shown in steps 421 to 424, using the lead insector as the position to be detected on the inner ring track, the compensator can obtain one position error for each of the p positions on the inner ring track each time the optical storage medium rotates p times. Assuming that it is necessary to obtain N position errors for each position, the compensator controls the optical storage medium to rotate N × p times. Each time the optical storage medium rotates p times, the compensator performs steps 422-424, and after the optical storage medium has rotated N × p times, the N position errors for each of the multiple positions are obtained. Alternatively, the compensator controls the optical storage medium to rotate N × p times. In the rotation process, step 422 is performed sequentially, step 423 is performed once each time an inner ring track is scanned, and after the optical storage medium has rotated N × p times, step 424 is performed to obtain the N position errors for each of the multiple positions at once.

[0091] It should be understood that, during the detection process, each time the optical storage medium rotates p times, the servo laser scans p inner ring tracks. In this scanning process, the laser spot of the servo laser on the reference plane forms the beam track of the servo laser. Each time the optical storage medium rotates N × p times, the laser spot of the servo laser on the reference plane can form a beam track of the servo laser on the p inner ring tracks, and the helical p inner ring tracks are the ideal track when the servo laser scans the p inner ring tracks. For any beam track of the servo laser, the radial distance between the position of any lead insector on the ideal track and the beam track is the position error of the servo laser at that lead insector.

[0092] To further reflect the positional error between the servo laser's irradiation track and the ideal track, Figure 7 shows a diagram of the servo laser's irradiation track according to one embodiment of this application. Figure 7 shows multiple irradiation tracks of the servo laser. These multiple irradiation tracks are different, and the multiple positional errors obtained by the servo laser scanning the same lead insector multiple times are different.

[0093] In another example, Figure 8 shows the local position error of the same inner ring track according to one embodiment of this application. Figure 8 shows multiple position error curves (e.g., the black curves in Figure 8). Each position error curve shows the position error of the servo laser at the 750th to 1100th lead insectors of the same inner ring track. From Figure 8, it can be seen that the multiple position errors obtained by the servo laser scanning the same lead insector multiple times are different. It can be seen that the position error of the servo laser at each lead insector has vibration characteristics. Therefore, the compensator may extract a reproducible portion from the position error of the same lead insector and obtain a compensation value for that lead insector based on the reproducible portion (as shown in steps 403 and 404 below) so that when data is later read / written in the recording sector corresponding to that lead insector, the reproducible portion is compensated for in the tracking servo control of the servo laser, removing the reproducible portion in the position error and reducing the vibration amplitude of the position error. This can reduce the radial deviation between the beam track of the servo laser and the ideal track and improve the control accuracy of the tracking servo control.

[0094] 403: The compensator determines the repeatable runout (RRO) for each position based on multiple positional errors at each position, and the repeatable runout is the repeatable portion of the positional errors.

[0095] In addition to reproduction error, arbitrary position The error The difference further includes non-repeatable runout (NRRO), which is the non-repeatable portion of the position error. There exists one repeatable error at any given position, and there can be multiple non-repeatable errors at any given position.

[0096] The reproduction error for any given position is the average value of multiple position errors for that position, and the multiple non-reproduction errors for any given position are the difference between the multiple position errors and the reproduction error for that position.

[0097] Let us use an arbitrary inner ring lead-in track as an example. Assuming that there are M positions (in other words, lead in sectors) on the inner ring lead-in track, and that the reproduction error of position j among the M positions is denoted as RRO(j), then the compensator is the N position errors of position j and the following RRO(j) formula:

number

[0098] M is the total number of positions (in other words, lead in sectors) on a specific inner ring lead-in track, N is the total number of position errors at position j on the inner ring lead-in track, k is the sampling number of the position errors, j is the number of a specific position on the inner ring lead-in track, and PES(k,j) is the k-th sampled position error at position j on the inner ring lead-in track, in other words, the k-th position error among the N position errors at position j.

[0099] Assuming there are N non-reproducible errors at position j, and that the j non-reproducible error among the N non-reproducible errors is denoted as NRRO(k,j), the compensator is given by the reproducible error RRO(j), the position error PES(k,j), and the following NRRO(k,j) equation:

number

[0100] According to the method described above, the compensator can obtain the reproducibility error and non-reproducibility error for each position on the p inner ring lead-in tracks. To further reflect the difference between the reproducibility error and position error at the same position, please refer to the reproducibility error curve shown by the white line in Figure 8. This reproducibility error curve shows the reproducibility error of the servo laser from the 750th lead insector to the 1100th lead insector on the inner ring track. Clearly, the reproducibility error at the same position is smaller than the position error at the same position.

[0101] 404: The compensator determines the compensation value for each position based on the reproducibility error and transfer function of each position.

[0102] The compensator uses the reproducibility error of each position as the compensation value for each position. Alternatively, the high-frequency portion within the reproducibility error of each position is used as the compensation value for each position.

[0103] For example, the high-frequency portion within the reproduction error of each position is obtained using steps 441 and 442 below.

[0104] Step 441: The compensator performs a frequency domain transformation on the reproducibility error at each position to obtain multiple frequency domain reproducibility errors at each position, the multiple frequency domain reproducibility errors corresponding to different frequencies.

[0105] The frequency-domain reproduction error is the amplitude of the reproduction error at the corresponding frequency.

[0106] In one possible implementation, for any given position, the compensator performs a Fourier transform on the reproducibility error of that position to convert the reproducibility error at that position from the time domain to the frequency domain, thereby obtaining multiple reproducibility errors for that position in the frequency domain range (in other words, frequency domain reproducibility errors).

[0107] Using position j on the inner ring lead-in track as an example, the frequency domain reproduction error of position j is RRO f When denoted as (j), the compensator is expressed by the following Fourier transform:

number

[0108] i = 1, 2, ..., N / 2, and a i This is the sine function:

number

number

number

[0109] Using j=1 as an example, the frequency domain reproduction error RRO of the first position on the inner ring track f (1) is as follows:

number

[0110] Using j=2 as another example, the frequency domain reproduction error RRO of the second position on the inner ring track f (2) is as follows:

number

[0111] The frequency domain range can include multiple frequencies, and the compensator is the frequency domain reproduction error RROf According to equation (j), the frequency domain reproduction error RRO of position j on the inner ring track at any frequency f is given by f (j) can be calculated.

[0112] Step 442: The compensator determines the compensation value for each position based on the high-frequency reproducibility error and transfer function within the multiple frequency-domain reproducibility errors for each position, where the high-frequency reproducibility error is the frequency-domain reproducibility error whose corresponding frequency is greater than or equal to the frequency threshold.

[0113] The frequency threshold may be set based on a specific implementation scenario. For example, the frequency threshold may be 1500 Hz or higher. The range of values ​​for the frequency threshold is not limited to this embodiment of this application.

[0114] For any given position, the compensator uses the frequency domain reproduction error of that position at the frequency threshold as the high-frequency reproduction error of that position, or uses the frequency domain reproduction error of that position at a frequency higher than the frequency threshold as the high-frequency reproduction error of that position.

[0115] Since positional error is a time-domain parameter, to facilitate subsequent compensation of positional error, the compensator adjusts the high-frequency reproducibility error of any given position. frequency From the domain time The system is converted to a domain, the time domain reproducibility error for that location is obtained, and this time domain reproducibility error is determined as the compensation value for that location.

[0116] In one possible implementation, the compensator uses the product of the high-frequency reproduction error at the location and the target frequency as the frequency-domain reproduction error compensation value, where the target frequency is greater than or equal to a frequency threshold. The compensator performs an inverse Fourier transform on the frequency-domain reproduction error compensation value at the location to convert it from the frequency domain to the time domain, obtains the time-domain reproduction error compensation value at the location at the target frequency, and uses this time-domain reproduction error compensation value as the compensation value at the location.

[0117] The inner ring lead in track is used as an example, and the compensator is the frequency domain reproducibility error compensation value RRO of position j at frequency f. f For (j), the following inverse Fourier transform is given:

number

[0118] f0 is the reference frequency of the rotational speed of the optical storage medium, i is a multiple of the reference frequency, and A i is the inverse Fourier real amplitude, and B i This is the frequency domain reproduction error compensation value (RRO). f (j) is the real amplitude of the transfer function of the tracking control loop used to calculate θ, where θ is the real amplitude of the transfer function of the tracking control loop used to calculate (j). i Φ is the phase of the transfer function of the tracking control loop at frequency. i This is the frequency domain reproduction error compensation value RRO at frequency f. f This is the phase of (j).

[0119] When the compensation value for position j is determined, the target frequency is denoted as f, and the time-domain reproducibility error compensation value a for position j at the target frequency f is determined according to the inverse Fourier transform formula described above. if The time domain reproducibility error compensation value a is calculated and calculated. if This is used as the compensation value for position j.

[0120] High-frequency domain reproducibility errors are primarily caused by disturbances. Excessively high high-frequency domain reproducibility errors can cause crossing of data tracks being written. Therefore, high-frequency domain reproducibility errors are a critical factor affecting the control accuracy of the tracking servo control of a servo laser. Based on steps 441 and 442, the high-frequency reproducibility error can be extracted from the reproducibility error of each position, and the high-frequency reproducibility error of each position is used as compensation for each position. When the position error of the servo laser at each position is compensated based on the compensation value for each position, the high-frequency reproducibility error of the position error at each position can be eliminated, and the oscillation amplitude of the position error in the high-frequency range can be reduced. This improves the control accuracy of the tracking servo control of the servo laser and avoids crossing of data tracks being written.

[0121] It should be understood that the process shown in steps 402-404 is a process of obtaining compensation values ​​for multiple positions based on the transfer function and the detection results of detecting multiple positions in the optical storage medium.

[0122] 405: The compensator stores compensation values ​​for multiple positions.

[0123] For example, the compensator establishes a mapping relationship between the identifier of each of the multiple locations and the compensation value of each location. For example, the compensator establishes a mapping relationship between the multiple locations and compensation values ​​shown in Table 1, based on the identifier of each of the multiple locations and the compensation of each location. As shown in Table 1, the identifier of each location includes the lead-in track number (in other words, the track number) of that location and the number of that location on the lead-in track. For example, the location is a lead-in sector, and the number of the location on the lead-in track is the sector number. Table 1 shows an example where M locations of each lead-in track in p lead-in tracks are recorded, and T (ref,p)is the number of the p-th lead-in track from the center of the lead-in layer, and the values ​​of p and M are not limited to this embodiment of this application. As shown in Table 1, the compensation of the positional error at each position using a compensation value is reflected in the compensation of the track width at each position. Therefore, the compensation value at each position is a percentage of the track width. Lead-in track T (ref,1) Let sector 1 of the recording layer be used as an example. When data is read / written at the position corresponding to sector 1 of the recording layer, the track width is compensated by (-0.45%) for sector 1. As shown in Table 1, the track width of the first lead-in track is represented by W(1), and similarly, the track width of the p-th lead-in track is represented by W(p). [Table 1]

[0124] As shown in Table 1, Table 1 further records the positions of the data tracks generated when data is written after the positional error of each position has been compensated based on the compensation value for each position. In some other embodiments, the positions of the data tracks generated when data is written are not recorded in Table 1.

[0125] After a mapping relationship is established between multiple locations and compensation values, the compensator stores the mapping relationship for later queries. For example, the compensator stores the mapping relationship when retrieving data. / Write The data is stored in the device's memory or in the memory of the electronic device where the data read / write device is located. The storage location of the mapping relationship is not limited to this embodiment of this application.

[0126] Memory configured to store mapping relationships may be non-volatile random-access memory and / or volatile memory. Non-volatile memory may be read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically EPROM (EEPROM), or flash memory. Volatile memory may be random-access memory (RAM). As examples rather than limitations, many forms of RAM may be used, such as static RAM (SRAM), dynamic random-access memory (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0127] In some other embodiments, after compensation-based tracking servo control is enabled for the servo laser, the compensation values ​​for multiple positions are acquired through detection and do not need to be acquired in advance. In this case, it is not necessary to store the compensation values ​​for multiple positions. Therefore, step 405 is an optional step, and in Figure 4, a dashed box is used to indicate that step 405 is an optional step.

[0128] According to the method provided in this embodiment of this application, multiple locations in an optical storage medium are detected and compensation values ​​for these locations are obtained, and these obtained compensation values ​​are applicable to the optical storage medium. When data is subsequently read from / written to / from these locations in the optical storage medium, the positional error of the corresponding location can be accurately compensated using appropriate compensation values, thereby reducing the positional error of the corresponding location. This improves the control accuracy of the tracking servo control of the optical storage medium.

[0129] The following describes in detail the process of performing tracking servo control based on compensation values ​​for multiple positions in an arbitrary optical storage medium.

[0130] Figure 9 is a flowchart of a servo control method for an optical storage medium according to one embodiment of this application. The method is performed by a compensator in a data read / write device.

[0131] 901: The compensator obtains a compensation value corresponding to the read / write position on the optical storage medium.

[0132] The optical storage medium is any optical storage medium taken into a data read / write device where the compensator is located. The read / write location is any recording sector on any recording layer within the optical storage medium, and the compensation value corresponding to the read / write location is the compensation value of the lead in sector corresponding to that location in the optical storage medium. For ease of explanation, the read / write location is referred to as the target recording sector, the recording layer on which the target recording sector is located is referred to as the target recording layer, the lead in sector corresponding to the target recording sector is referred to as the target lead in sector, and the lead in track on which the target lead in sector is located is referred to as the target lead in track.

[0133] When a target recording sector reads or writes data, or before a target recording sector reads or writes data, the controller uses the target lead-in sector on the reference plane as the target position for the servo laser. For example, if the target recording sector is the first sector of the first recording track of the first recording layer of the optical storage medium, the target position is the first sector of the first lead-in track on the reference plane. In another example, if the target recording sector is the first sector of the first recording track of the second recording layer of the optical storage medium, the target position is the first sector of the first lead-in track on the reference plane. It should be understood that the same recording sector in different recording layers corresponds to the same lead-in sector on the reference plane.

[0134] The control unit transmits the target position identifier to the compensator, instructing the compensator to illuminate the target position with the servo laser, and the compensator compensates for the positional error between the servo laser's illumination position and the target position. After obtaining the target position identifier, the compensator calculates the position between multiple positions and compensation values ​​in the optical storage medium. Opposite The compensation value for the target location is queried based on the relationship (shown in Table 1). The compensation value for the target location is the compensation value corresponding to the read / write location.

[0135] In some embodiments, if a compensation value for the target position cannot be found, a compensation value for at least one position is obtained by detecting that at least one position on the reference plane of the optical storage medium, and that at least one position includes the target position. In this case, a compensation value for the target position can be obtained. For the process of detecting that at least one position on the reference plane of the optical storage medium and obtaining a compensation value for that at least one position, please refer to the process shown in steps 402 to 404, and the details will not be described again here.

[0136] 902: The compensator compensates for the position error of the servo laser of the data read / write device based on the compensation value.

[0137] For example, the compensator subtracts the servo laser detection position from the target position to obtain the servo laser position error, and adds the compensation value obtained in step 901 to the position error to obtain the compensated position error.

[0138] 903: The compensator controls the objective lens of the data read / write device based on the compensated position error to perform data read / write at that position in the optical storage medium.

[0139] The objective lens is shared by the read / write laser and the servo laser.

[0140] For example, the compensator generates a tracking servo signal based on the compensated position error, and this tracking servo signal is used to remove the compensated position error. The compensator transmits the tracking servo signal to a torquer on the objective lens, which drives the objective lens to move radially across the optical storage medium based on the tracking servo signal, so that the servo laser illuminates the compensated target position and the read / write laser illuminates the compensated read / write position to read / write data from / to the compensated read / write position. The radial difference between the target position and the compensated target position is less than or equal to the compensated value of the target position, and the radial difference between the compensated read / write position and the read / write position is less than or equal to the compensated value of the target position.

[0141] The above describes an example in which the compensator controls the objective lens based on a compensation value for the target position. In some other embodiments, the compensator controls a tracking servo controller C in a tracking servo control circuit for controlling the objective lens based on a compensation value for the target position. Figure 5 is used as an example. An addition / subtraction unit G in the tracking control circuit subtracts the detected servo laser position from the target position to obtain the servo laser position error. The compensator transmits the compensation value for the target position to the addition / subtraction unit G. The addition / subtraction unit G adds the compensation value and the position error to obtain the compensated position error and transmits the compensated position error to the tracking servo controller C. The tracking servo controller C generates a tracking servo signal based on the compensated position error and transmits the tracking servo signal to the Torca P. The Torca P controls the objective lens based on the tracking servo signal.

[0142] The above description uses an example where the read / write laser and the servo laser share a single objective lens. In some other embodiments, the read / write laser and the servo laser do not share a single objective lens, but use different objective lenses. In this case, the compensator controls the objective lens of the read / write laser and the objective lens of the servo laser separately based on the compensated position error using the objective lens control method described above.

[0143] In some embodiments, during the data reading and writing process, the compensator further determines whether previously written data has been overwritten on the target recording layer currently being read or written. If the previously written data has been overwritten, it re-detects multiple locations on the optical storage medium and updates the compensation values ​​for those locations. For example, each time a first-numbered recording track is written to the target recording layer, a first-numbered data track is acquired, a detector detects the intersection state of the first-numbered data track, and if any of the data tracks within the first-numbered data track intersect with an adjacent data track, the data of that data track extends over the data of the adjacent data track at the intersection. In this case, multiple locations on the optical storage medium are re-detected, and new compensation values ​​for those locations are acquired. The existing compensation values ​​for the multiple locations are changed to new compensation values, and in order to acquire a new data track, the data is rewritten to the recording track based on the compensation value corresponding to the location on the recording track corresponding to any of the above data tracks, thereby avoiding the new data track intersecting with an adjacent data track. The first number is 1 or greater and is less than the total number of recording tracks on the recording layer. The first number described above is not limited to this embodiment of this application.

[0144] The compensator's detection of the crossover state of a first-numbered data track includes detecting the bit error rate of the first-numbered data track. If the bit error rate of any data track is greater than or equal to the bit error rate threshold, that data track crosses with an adjacent data track; if the bit error rate of that data track is less than the bit error rate threshold, that data track does not cross with an adjacent data track. The bit error rate refers to the original bit error rate obtained by analyzing the data when the data read / write device reads the data from the optical storage medium. The bit error rate threshold can be set based on a specific implementation scenario, and the bit error rate threshold is not limited herein.

[0145] In some other embodiments, if any data track within a first number of data tracks intersects with an adjacent data track, detection is not performed for all of the multiple locations in the optical storage medium, but only the location corresponding to that data track is detected, the compensation value for the location corresponding to that data track is updated, the number of detected location results is reduced, and the compensation value is updated rapidly.

[0146] By updating the compensation value for that position, the accuracy of the compensation value is improved, and as a result, the position error of the servo laser can be accurately compensated in the process of performing tracking servo control on the servo laser, further improving the control accuracy of the tracking servo control.

[0147] According to the method provided in this embodiment of this application, since the read / write position in the optical storage medium corresponds to a lead insector on the reference plane of the optical storage medium, the current position error of the servo laser is compensated with a compensation value corresponding to the read / write position to reduce the current position error between the irradiation position of the servo laser on the reference plane and the lead insector. The objective lens shared by the servo laser and the read / write laser is controlled based on the reduced position error, thereby eliminating the compensated position error and improving the control accuracy of the servo laser control. As the position error of the servo laser is reduced, the position error between the irradiation position of the read / write laser and the read / write position is also reduced accordingly under the position guidance of the servo laser, and as a result the read / write laser acts on the read / write position as much as possible. When data is written to the read / write position, the width of the track where the read / write position is located can be reduced, and it can be avoided that it intersects with adjacent tracks. When data is read from a read / write location, it is possible to read as much of the data recorded at that location as possible, ensuring the accuracy of the read data.

[0148] The embodiment shown in Figure 9 illustrates an example in which tracking servo control is performed on a servo laser based on a compensation value corresponding to a position when data is read or written at any position on any track of any recording layer of an optical storage medium. Therefore, when data is read or written at any position on each recording layer of the optical storage medium, the compensator can perform tracking servo control on the servo laser based on the process shown in Figure 9. In other words, when data is read or written to all tracks of the recording layers of the optical storage medium, tracking servo control can be performed on the servo laser using the process shown in Figure 9.

[0149] In some other embodiments, the compensator can perform tracking servo control on the servo laser using the process shown in Figure 9 only when reading or writing data at certain track locations on the recording layer, and does not perform tracking servo control using the process shown in Figure 9 when reading or writing data at other track locations on the recording layer. In other words, tracking servo control is performed based on the compensation value corresponding to the location only when the read / write location is on a certain specific track on the optical recording medium.

[0150] For example, some of the tracks mentioned above are tracks close to the center of the optical storage medium (in other words, inner ring tracks). Figure 10 is a diagram of the control logic of tracking servo control according to one embodiment of this application. As shown in Figure 10, when step 901 is performed, after the target position of the read / write location on the reference plane is obtained, the compensator determines whether the target position is located on the inner ring track of the reference plane. If the target position is located on the inner ring track, the compensator continues to perform steps 901 to 903, for example, the compensator compensates for the position error of the target position, and the servo control circuit performs tracking servo control based on the compensated position error to read or write data at that position on the inner ring track as far as possible. According to this method, when data is read / written on the inner ring track, the positional error of the servo laser is reduced, and the positional error between the irradiation position of the read / write laser on the inner ring track of the recording layer and the read / write position is also reduced under the guidance of the servo laser. As a result, the read / write laser acts on the read / write position as much as possible, and when data is written to the read / write position, the track width of the read / write position on the data track can be reduced to avoid writing to adjacent data tracks. When data is read at the read / write position, as much of the data recorded at that position as possible can be read, and the accuracy of the read data can be ensured.

[0151] As shown in Figure 10, if the target position is not located on the inner ring track of the reference plane but on the outer track of the reference plane, the compensator does not perform steps 901 to 903. In other words, the compensator does not compensate for the position error of the target position. Therefore, the control process of the tracking control circuit is not interfered with, and the tracking control circuit performs tracking servo control based on the position error of the target position before compensation. As described above, the position error of the inner ring track of the servo laser is compensated so that the data tracks of the recording layer do not intersect. When the tracking control circuit uses the inner ring track of the recording layer when performing tracking servo control for a servo laser irradiated onto the outer ring track, the servo control accuracy of the outer ring track can be improved if the data tracks of the inner ring of the recording layer do not intersect. For example, when a tracking control circuit using an ATS-based position control method reads and writes data to / from the outer ring track of the recording layer, the inner ring track written by the recording layer may be used.

[0152] Based on the aforementioned servo control method for optical storage media, the process by which a data read / write device writes data to multiple recording layers of an optical storage medium is described as follows:

[0153] For example, Figure 11 is a diagram of a data writing process for an optical storage medium according to one embodiment of this application. As shown in Figure 11, in the process of starting the system, after it is detected that the optical storage medium has been placed on the rotary table of the data read / write device, the control unit of the data read / write device controls the rotary table to rotate the optical storage medium, initializes the control parameters of each servo control circuit (such as the tracking servo control circuit and the focus servo control circuit) within the data read / write device, and controls the torque of the objective lens to move the objective lens to a position corresponding to the lead-in zone of the servo surface.

[0154] The control unit initiates tracking servo control as follows: it controls the first laser emitter to emit a read laser onto the optical storage medium, controls the second laser emitter to emit a servo laser onto the optical storage medium, controls the torque of the objective lens to irradiate the read laser onto the lead-in zone of the recording layer of the optical storage medium, and moves the servo laser to irradiate the lead-in zone on the reference plane to a position corresponding to the lead-in zone; it acquires the photodetector signal of the servo laser from the first photodetector integrated circuit, extracts the laser spot position of the read / write laser from the photodetector signal, and determines the focusing error of the read / write laser based on that position. The system acquires the reflected read laser by starting focus servo control of the read laser based on the focusing error so that the read / write laser is irradiated onto the lead-in zone of the recording layer; starts tracking servo control of the servo laser using a compensator, calculates the servo laser's reproducibility error, generates a compensation value for the inner ring track of the servo laser based on the servo laser's reproducibility error, and starts compensating for the servo laser's position error; then decodes the metadata of the lead-in zone from the photodetector signal of the reflected read laser and writes the data to the recording layer of the optical storage medium based on the metadata.

[0155] Next, the control unit initiates the writing process as follows: Assuming that the inner ring track is the reference plane and tracks 1 through 500 of the recording layer, after the write command for recording layer L1 is read, the laser intensity of the read / write laser is adjusted so that the read / write laser changes from a read laser to a write laser; tracking servo control of the servo laser is enabled; data is written sequentially to each track of recording layer L1 in the sequence from the inner to the outer tracks; in the process of writing data to tracks 1 through 500 of recording layer L1, The bolster position error compensation is enabled; after data is written to the 500th track, data continues to be written to all tracks except the first 500 until data is written to all tracks of recording layer L1; when a write command for recording layer L2 is read, the first group of compensation mirrors is controlled to cause the irradiation position of the write laser to jump from recording layer L1 to recording layer L2; data is written to recording layer L2 in the same manner as data was written to recording layer L1 until data is written to the entire recording layer L2; and so on, until data is written to all recording layers of the optical storage medium. To be continued .

[0156] In the embodiment shown in Figure 11, the data read / write device is described using an example in which data is written sequentially to each recording layer of the optical storage medium based on the order of the recording layers. In some other embodiments, the data read / write device does not have to write data to the recording layers based on the order of the recording layers, but can write data to the recording layer specified by the write command according to the write command. In the embodiment shown in Figure 12, when data is written to each recording layer, the data read / write device writes data sequentially to the tracks of the recording layers in a sequence from the inside to the outside of the tracks. In some other embodiments, instead of writing data to the tracks of the recording layers in a sequence from the inside to the outside of the tracks, the data read / write device writes data to the track or location of the track specified by the write command according to the write command.

[0157] When a compensation value for position error is obtained based on high-frequency reproduction error, please refer to the comparison figure of servo laser position errors shown in Figure 12 according to one embodiment of this application to further reflect the beneficial effects brought about by performing tracking servo control on the servo laser based on the compensated position error in this application. The amplitude-frequency curve formed by "*" is used to reflect the change in the amplitude of the servo laser position error in the frequency domain after tracking servo control is performed based on the compensated position error (in other words, the result of using the control solution of this application). The amplitude-frequency curve of the black line is used to reflect the change in the amplitude of the servo laser position error in the frequency domain after tracking servo control is performed based on the uncompensated position error (in other words, the control result of the tracking control circuit without interference with the tracking control circuit). As can be seen from these two amplitude-frequency curves, after the control solution of this application is used, the servo laser position error is clearly reduced in the high-frequency range, the servo laser position error can be reduced by 30% to 50%, the width of the written track can be reduced by 6 nm to 9 nm, and the overhang between tracks can be reduced by 5% to 10%.

[0158] In one embodiment, a servo control device for an optical storage medium is further provided. This servo control device can be configured as a compensator in the above-described embodiment and is configured to perform the method performed by the compensator. For example, Figure 13 is a diagram of a servo control device for an optical storage medium according to one embodiment of this application. The servo control device 1300 shown in Figure 13 is An acquisition module 1301 configured to acquire a compensation value corresponding to the read / write position in an optical storage medium, A compensation module 1302 configured to compensate for the position error of the servo laser of the data read / write device based on a compensation value, The system includes a control module 1303 configured to control the objective lens of a data read / write device based on a compensated position error to perform data read / write operations at that position in the optical storage medium.

[0159] In one possible implementation, the read / write location is located on a track close to the center of the optical storage medium.

[0160] In one possible implementation, the read / write locations mentioned above are located on a specific track within the optical storage medium.

[0161] In one possible implementation, the servo control device 1300 further includes: Includes a detection module configured to detect multiple locations in an optical storage medium and obtain compensation values ​​for said multiple locations.

[0162] In one possible implementation, the detection module is: A detection submodule configured to detect multiple positions in an optical storage medium and acquire multiple positional errors for each of those positions, A first determination submodule configured to determine the reproduction error for each position based on multiple position errors for each position, wherein the reproduction error refers to the reproduced portion of the position error, and the first determination submodule, It includes a second determination submodule configured to determine a compensation value for each position based on the reproduction error of each position.

[0163] In one possible implementation, the second decision submodule is: A frequency domain transformation is performed on the reproduction error of each position to obtain multiple frequency domain reproduction errors for each position, and these multiple frequency domain reproduction errors correspond to different frequencies. The compensation value for each position is determined based on the high-frequency reproduction error within the above-mentioned multiple frequency domain reproduction errors for each position, and the high-frequency reproduction error is configured to be a frequency domain reproduction error in which the corresponding frequency is greater than or equal to the frequency threshold.

[0164] In one possible implementation, the servo control device 1300 further includes: Includes an acquisition module 1301 configured to acquire the transfer function of the tracking control circuit of a servo laser in a data read / write device, The detection module is further configured to acquire compensation values ​​for multiple locations based on the transfer function and the detection results of detections performed for multiple locations in the optical storage medium.

[0165] In one possible implementation, the detection module further: De During the data read / write process, if the written data is overwritten, multiple locations on the optical storage medium are detected again and the compensation values ​​for those locations are updated. ru, It is configured in this way.

[0166] Based on the aforementioned implementations, these implementations can be further combined to provide even more implementations.

[0167] It should be understood that the servo control device 1300 corresponds to the compensator in the method embodiment described above. The modules within the servo control device 1300, as well as the other operations and / or functions described above, are used to implement the steps and methods performed by the compensator in the method embodiment, respectively. For specific details, please refer to the method embodiment described above. For brevity, the details will not be described again here.

[0168] It should be understood that when the servo control device 1300 compensates for the position error of the servo laser, the division of the functional modules described above is used merely as an illustrative example. In actual applications, the functions described above may be assigned to different functional modules for implementation according to requirements; that is, the internal configuration of the servo control device 1300 is divided into different functional modules to implement all or some of the functions described above. In addition, the servo control device 1300 provided in the above embodiments and the method embodiments described above relate to the same concept. For specific implementation processes, please refer to the method embodiments described above. Details will not be described again here.

[0169] In one embodiment, the compensator or servo control device 1300 may be implemented using a processor. The processor is configured to execute program code, and as a result, a data read / write device on which the processor is located executes the program code to implement the servo control method for an optical storage medium provided in an embodiment of this application. For example, the processor may include one or more processing cores, and may be, for example, a 4-core processor or an 8-core processor. The processor may be implemented in at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), or programmable logic array (PLA).

[0170] Embodiments of this application further provide a compensator for use in a data read / write device. The data read / write device is configured to read / write data to and from an optical storage medium. The data read / write device is any of the data read / write devices described above. The compensator includes a processor, the processor is configured to execute program code, and as a result, the compensator performs the servo control method for the optical storage medium in the embodiments described above. For example, Figure 14 is a diagram of the configuration of a compensator according to one embodiment of this application. The compensator 1400 includes one or more processors 1401 and one or more memories 1402. One or more memories 1402 are coupled to one or more processors 1401. One or more memories 1402 are configured to store at least one program code. When one or more processors execute the at least one program code, the compensator 1400 performs the associated method steps described above to implement the servo control method for the optical storage medium in the embodiments described above. The compensator 1400 may be a chip, component, or module.

[0171] In one embodiment, a computer-readable storage medium is further provided, such as a memory containing at least one program code. The at least one program code is executed by a processor in a data read / write device to complete the servo control method for the optical storage medium in the above-described embodiment. For example, the processor may be configured as the compensator described above. For example, the computer-readable storage medium is a non-temporary computer-readable storage medium such as a read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), magnetic tape, floppy disk (registered trademark), or optical data storage device.

[0172] Embodiments of this application further provide a computer program product or computer program, which comprises at least one program code, which is stored in a computer-readable storage medium. A processor of a data read / write device reads and executes the at least one program code from the computer-readable storage medium, thereby causing the data read / write device to perform the servo control method for the optical storage medium in the embodiments described above. For example, the processor may be configured as the compensator described above.

[0173] The apparatus, devices, computer-readable storage media, computer program products, and chips provided in the embodiments are all configured to perform the corresponding methods provided above. Therefore, for the beneficial effects that can be achieved, please refer to the beneficial effects of the corresponding methods provided above. Further details will not be described again here.

[0174] In some embodiments provided in this application, it should be understood that the disclosed devices and methods may be implemented in other ways. For example, the described device embodiments are merely examples. For example, the division into modules or units is merely a logical functional division, and other divisions may be used in actual implementations. For example, multiple units or components may be combined or integrated into another device, or some mechanisms may be ignored or not performed. In addition, the shown or described mutual coupling, direct coupling, or communication connection may be implemented by using some interface. Indirect coupling or communication connection between devices or units may be implemented electronically, mechanically, or in other forms.

[0175] Units described as separate parts may or may not be physically separate, and parts shown as units may be one or more physical units, located in one place, or distributed in different locations. Some or all of the units may be selected based on the actual requirements to achieve the objectives of the solution of the embodiment.

[0176] In addition, the functional units in the embodiments of this application may be integrated into a single processing unit, or each unit may exist physically independently, or two or more units may be integrated into a single unit. The integrated unit may be implemented in hardware form or in the form of a software functional unit.

[0177] When an integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, the integrated unit may be stored in a readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the portion that contributes to the prior art, or all or part of the technical solution, may be implemented in the form of a software product. The software product is stored in a storage medium and includes several instructions for instructing a device (which may be a single-chip microcomputer or chip, etc.) or processor to perform all or part of the steps of the method described in embodiments of this application. The aforementioned storage medium includes any medium capable of storing program code, such as a USB flash drive, removable hard disk drive, ROM, RAM, magnetic disk, or optical disk.

[0178] In this application description, unless otherwise specified, “ / ” means “or.” For example, A / B can mean A or B. In this specification, the term “and / or” describes only the relationship between the related objects and indicates that three relationships may exist. For example, A and / or B can represent three cases: only A exists, both A and B exist, and only B exists. Also, “at least one” means one or more, and “multiple” means two or more. For example, terms such as “first” and “second” do not limit the number or order of execution, and terms such as “first” and “second” do not indicate a clear distinction.

[0179] In this application, the terms “example,” “for example,” or similar terms are used to indicate that an example, illustration, or explanation is being given. No embodiment or design scheme described as “example” or “for example” in this application is described as being preferable or having more advantages than other embodiments or design schemes. More precisely, the use of terms such as “example” or “for example” is intended to present relative concepts in a specific manner.

[0180] The foregoing description is merely an optional embodiment of this application and is not intended to limit it. Any modification, equivalent substitution, or improvement made without departing from the spirit and principles of this application will fall within the scope of protection of this application.

Claims

1. A servo control method for optical storage media, The compensation value for the high-frequency reproduction error corresponding to the read / write position in the optical storage medium is obtained, and the reproduction error is the reproduced portion of the position error of the servo laser of the data read / write device. The position error is compensated based on the aforementioned compensation value. Based on the compensated position error, the objective lens of the data read / write device is controlled to perform data read / write at the position in the optical storage medium. A method having the following characteristics.

2. Obtaining the compensation value for the high-frequency reproduction error corresponding to the read / write position in the optical storage medium is, The compensation value for the high-frequency reproducibility error is determined based on the measured value and transfer function of the reproducibility error. The method according to claim 1, wherein the method is as follows:

3. Obtaining the compensation value for the high-frequency reproduction error corresponding to the read / write position in the optical storage medium is, A frequency domain transformation is performed on the read / write position reproduction error to obtain multiple frequency domain reproduction errors, and these multiple frequency domain reproduction errors correspond to different frequencies. The compensation value for the read / write position is determined based on the high-frequency reproduction error within the plurality of frequency domain reproduction errors, and the high-frequency reproduction error is a frequency domain reproduction error corresponding to a frequency above the frequency threshold. The method according to claim 1 or 2, wherein the method is as follows:

4. The method according to any one of claims 1 to 3, wherein the read / write position is located on a track close to the center of the optical storage medium.

5. The method according to any one of claims 1 to 3, wherein the read / write position is located on a portion of a track in the optical storage medium.

6. Before obtaining the compensation value corresponding to the read / write position in the optical storage medium, the method further: Multiple positions in the optical storage medium are detected and compensation values ​​for these multiple positions are obtained. The method according to any one of claims 1 to 4, wherein the method is as follows:

7. Detecting multiple positions in the optical storage medium and obtaining compensation values ​​for those multiple positions is, The plurality of positions in the optical storage medium are detected and the plurality of positional errors of each of the plurality of positions are obtained. Based on the multiple positional errors of each position, the reproduction error of each position is determined, and this reproduction error is the reproduced portion of the positional error. Based on the reproduction error for each position, a compensation value is determined for each position. The method according to claim 6, wherein the above is achieved.

8. Before detecting multiple positions in the optical storage medium and obtaining compensation values ​​for those multiple positions, the method further: The transfer function of the tracking control circuit of the servo laser in the data read / write device is obtained, Based on the transfer function and the detection results obtained by detecting the plurality of positions in the optical storage medium, the compensation values ​​for the plurality of positions are obtained. The method according to claim 6 or 7, wherein the above is achieved.

9. This method further, In the data read / write process, if the written data is overwritten, the plurality of positions in the optical storage medium are detected again and the compensation values ​​for the plurality of positions are updated. The method according to any one of claims 6 to 8, wherein the method is characterized by the fact that

10. A servo control device for optical storage media, An acquisition module configured to acquire a compensation value for the high-frequency reproducibility error corresponding to the read / write position in an optical storage medium, wherein the reproducibility error is the reproducible portion of the position error of the servo laser of the data read / write device, and the acquisition module and A compensation module configured to compensate for the position error based on the compensation value, A control module configured to control the objective lens of the data read / write device based on the compensated position error to perform data read / write at the position in the optical storage medium, A device having.

11. To obtain the compensation value of the high-frequency reproduction error corresponding to the read / write position in the optical storage medium, The compensation value for the high-frequency reproducibility error is determined based on the measured value and transfer function of the reproducibility error. The apparatus according to claim 10, having the following characteristics.

12. To obtain the compensation value of the high-frequency reproduction error corresponding to the read / write position in the optical storage medium, A frequency domain transformation is performed on the read / write position reproduction error to obtain multiple frequency domain reproduction errors, and these multiple frequency domain reproduction errors correspond to different frequencies. The compensation value for the read / write position is determined based on the high-frequency reproduction error within the plurality of frequency domain reproduction errors, and the high-frequency reproduction error is a frequency domain reproduction error corresponding to a frequency above the frequency threshold. The apparatus according to claim 10 or 11, having the following characteristics.

13. The apparatus according to any one of claims 10 to 12, wherein the read / write position is located on a track close to the center of the optical storage medium.

14. The apparatus according to any one of claims 10 to 12, wherein the read / write position is located on a portion of a track in the optical storage medium.

15. The device further, A detection module configured to detect multiple positions in the optical storage medium and acquire compensation values ​​for those multiple positions, The apparatus according to any one of claims 10 to 14, having the following features.

16. The detection module is A detection submodule configured to detect the plurality of positions in the optical storage medium and to acquire a plurality of positional errors for each of the plurality of positions, A first determination submodule configured to determine the reproduction error of each position based on the plurality of position errors of each position, wherein the reproduction error is the reproduced portion of the position error, and the first determination submodule, A second determination submodule configured to determine the compensation value for each position based on the reproduction error for each position, The apparatus according to claim 15, having the following features.

17. The acquisition module is further configured to acquire the transfer function of the tracking control circuit of the servo laser in the data read / write device. The detection module is further configured to acquire the compensation values ​​for the plurality of locations based on the transfer function and the detection results of the detection performed on the plurality of locations in the optical storage medium. The apparatus according to claim 15 or 16.

18. The aforementioned detection module further, In the data read / write process, if the written data is overwritten, the plurality of positions in the optical storage medium are detected again and the compensation values ​​for the plurality of positions are updated. The apparatus according to any one of claims 15 to 17, configured as follows.

19. A data read / write device for an optical storage medium, wherein the data read / write device has a processor, the processor is configured to execute program code to enable the data read / write device to perform the method described in any one of claims 1 to 9.

20. A compensator used in a data read / write device, wherein the data read / write device is configured to read data from and write data to an optical storage medium, and the compensator has a processor, the processor is configured to execute program code to enable the compensator to perform the method according to any one of claims 1 to 9.

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