Servo control method and apparatus for optical storage medium, and data read / write apparatus

Abstract

The present application belongs to the technical field of optical storage. Disclosed are a servo control method and apparatus for an optical storage medium, and a data read / write apparatus. In the present method, with regard to a position error, of servo light, between an irradiation position on a reference surface and a boot sector, the position error of the servo light is compensated for by using a compensation value of a high-frequency repeatable error corresponding to a position to be subjected to reading and writing in an optical storage medium, so as to eliminate a repeatable portion from the position error, such that the current position error can be reduced; and an objective lens shared by the servo light and read / write light is controlled on the basis of the reduced position error, so as to eliminate the compensated position error, such that the control accuracy of tracking servo control of the servo light is improved.

Description

Servo control method, device and data reading and writing device for optical storage medium

[0001] This application claims priority to Chinese patent application No. 202310704017.4 filed on June 13, 2023, entitled “Servo control method, device and data reading and writing device for optical storage medium”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of optical storage technology, and in particular to a servo control method and device and a data reading and writing device for an optical storage medium. Background Art

[0003] Optical storage media are widely used to store cold data due to their ability to preserve data for a long time. Optical storage media include, for example, Blu-ray Discs (BDs) and Compact Discs (CDs).

[0004] When writing to an optical storage medium, the writing light and the servo light are focused onto the recording layer and the servo layer of the optical storage medium respectively through the same objective lens. Based on the error between the spot position of the servo light in the servo layer and the ideal track position (i.e., the position error of the servo light), the objective lens is controlled by tracking servo so that the subsequent writing light is irradiated onto the ideal track of the recording layer as much as possible, so that data can be written on the ideal track as much as possible, so that the written data can be arranged in the form of tracks on the recording layer.

[0005] At present, the control accuracy of the tracking servo control of servo light (such as red light) is about 18 nanometers (nm). However, the control accuracy of the tracking servo control required by high-density optical storage media is generally higher than 18 nm. Among them, high-density optical storage media refers to optical storage media in which the number of tracks in the recording layer exceeds the number threshold, that is, optical storage media in which the number of tracks in the recording layer is relatively large.

[0006] Taking high-density Blu-ray discs as an example, the tracking servo control accuracy required for writing light on Blu-ray discs is 9nm. Therefore, the current tracking servo control accuracy of the servo light falls far short of the required tracking servo control accuracy. When writing data to a Blu-ray disc, this insufficient tracking servo control accuracy can cause newly written data tracks on the recording layer to intersect with already written adjacent data tracks (i.e., track squeezing). This causes the newly written data to overwrite the already written data on the adjacent data track, resulting in the loss of the already written data on the adjacent data track. Therefore, a servo control method for optical storage media is urgently needed to improve the tracking servo control accuracy of the servo light.

[0007] Summary of the Invention

[0008] The present invention provides a servo control method, device, and data reading / writing device for optical storage media, which can improve the control accuracy of tracking servo control of servo light. The technical solution is as follows:

[0009] In a first aspect, a servo control method for an optical storage medium is provided, which method includes at least the following steps: first, obtaining a compensation value corresponding to a position to be read or written in the optical storage medium; then, based on the obtained compensation value, compensating for a position error of a servo light of a data reading and writing device; and then, based on the compensated position error, controlling an objective lens of the data reading and writing device to read or write data at the position of the optical storage medium.

[0010] This method compensates for the position error of the servo light through the compensation value corresponding to the position to be read or written in the storage medium to reduce the current position error. Based on the reduced position error, the objective lens used by the data reading and writing device when reading and writing data is controlled to eliminate the compensated position error, thereby improving the control accuracy of the tracking servo control of the servo light.

[0011] In a possible implementation, the location to be read or written is located on a track near the center of the optical storage medium.

[0012] Based on the above possible implementation methods, when reading and writing data on a track near the center of an optical storage medium, the position error of the servo light is reduced by using the compensation value corresponding to the position to be read and written on the track near the center. Therefore, under the guidance of the position of the servo light, data can be written as much as possible at the position to be read and written on the track near the center, and the track width of the written data track at the position to be read and written can be reduced to avoid writing to adjacent data tracks, so that the data tracks written on the track near the center do not intersect.

[0013] In a possible implementation, the location to be read or written is located on a partial track in the optical storage medium.

[0014] Based on the above possible implementation methods, when reading and writing data on a track near the center of an optical storage medium, the position error of the servo light is reduced by using the compensation value corresponding to the position to be read and written on a portion of the track. Therefore, under the guidance of the position of the servo light, data can be written as close to the position to be read and written as possible on this portion of the track, and the track width of the written data track at the position to be read and written can be reduced to avoid writing to adjacent data tracks, so that the data tracks written on this portion of the track do not intersect.

[0015] In a possible implementation, before obtaining the compensation value corresponding to the position to be read or written in the optical storage medium, the method further includes the following step: detecting multiple positions of the optical storage medium to obtain compensation values ​​for the multiple positions.

[0016] Based on the above possible implementation methods, multiple positions of the optical storage medium are detected to obtain compensation values ​​for these multiple positions, so that the obtained compensation values ​​can be applicable to the optical storage medium. Subsequently, when reading and writing data at the read and write positions corresponding to these multiple positions of the optical storage medium, the position errors of the corresponding positions can be accurately compensated by appropriate compensation values ​​to reduce the position errors of the corresponding positions, thereby improving the control accuracy of the tracking servo control of the optical storage medium.

[0017] In one possible implementation, the above-mentioned process of detecting multiple positions of the optical storage medium to obtain compensation values ​​for the multiple positions includes at least the following steps: first, detecting multiple positions of the optical storage medium to obtain multiple position errors for each of the multiple positions; then, based on the multiple position errors of each position, determining the repeatable error of each position, where the repeatable error refers to the repeatable part of the position error; and then, based on the repeatable error of each position, determining the compensation value for each position.

[0018] Based on the above possible implementation methods, high-frequency repeatable errors can be extracted from the repeatable errors of each position, and the high-frequency repeatable errors of each position can be used as compensation for each position, so that when the position error of the servo light at each position is compensated based on the compensation value of each position, the high-frequency repeatable errors in the position error of each position can be eliminated, and the oscillation amplitude of the position error in the high-frequency range can be reduced, thereby improving the control accuracy of the tracking servo control of the servo light and avoiding the intersection of the written data tracks.

[0019] In one possible implementation, the process of determining the compensation value for each position based on the repeatable error at each position includes the following steps: first, performing a frequency domain transform on the repeatable error at each position to obtain multiple frequency domain repeatable errors at each position; then, determining the compensation value for each position based on a high-frequency repeatable error among the multiple frequency domain repeatable errors at each position, wherein the multiple frequency domain repeatable errors correspond to different frequencies, and the high-frequency repeatable error refers to a frequency domain repeatable error whose corresponding frequency is greater than or equal to a frequency threshold.

[0020] Based on the above possible implementation methods, high-frequency repeatable errors can be extracted from the repeatable errors of each position, and the high-frequency repeatable errors of each position can be used as compensation for each position, so that when the position error of the servo light at each position is compensated based on the compensation value of each position, the high-frequency repeatable errors in the position error of each position can be eliminated, the oscillation amplitude of the position error in the high-frequency range can be reduced, and the control accuracy of the tracking servo control can be improved.

[0021] In one possible implementation, before detecting multiple positions of the optical storage medium to obtain compensation values ​​for the multiple positions, the method further includes the following steps: obtaining a transfer function of a tracking control circuit of a servo light in a data reading and writing device; and obtaining compensation values ​​for the multiple positions based on the transfer function and the detection results of the multiple positions of the optical storage medium.

[0022] Based on the above possible implementation methods, by obtaining the transfer function of the tracking control circuit of the servo light in the data reading and writing device, the compensation value obtained based on the transfer function is made more accurate. Using the accurate compensation value to compensate for the position error on the tracking control circuit can increase the compensation effect of the position error, thereby improving the control accuracy of the tracking servo control.

[0023] In a possible implementation, the method further includes the following steps: during the data reading and writing process, if the written data is overwritten, detecting multiple positions in the optical storage medium again to update the compensation values ​​of the multiple positions.

[0024] Based on the above possible implementation methods, these multiple positions are re-detected to obtain new compensation values ​​for the multiple positions, so that data can be re-written to the positions to be read and written according to the compensation values ​​corresponding to each position to obtain new data tracks, so as to avoid the new data tracks from intersecting with adjacent data tracks.

[0025] In a second aspect, a servo control device for optical storage media is provided, configured to execute the above-mentioned servo control method for optical storage media. Specifically, the servo control device includes a functional module configured to execute the method provided in the first aspect or any optional embodiment of the first aspect.

[0026] In a third aspect, a data reading and writing device for an optical storage medium is provided, the data reading and writing device including a processor, the processor being used to execute program code so that the data reading and writing device executes to implement the method provided in the first aspect or any optional embodiment of the first aspect.

[0027] In a fourth aspect, a compensator is provided for use in a data reading and writing device, which is used to read and write data on an optical storage medium. The compensator includes a processor, which is used to execute program code so that the compensator executes to implement the method provided in the first aspect or any optional method of the first aspect.

[0028] In a fifth aspect, a computer-readable storage medium is provided, in which at least one program code is stored. The at least one program code is read by a processor of a data reading and writing device to enable the data reading and writing device to execute the method provided in the first aspect or any optional method of the first aspect.

[0029] In the sixth aspect, a computer program product is provided, which includes at least one program code. When the at least one program code is executed by a processor in a data reading and writing device, the data reading and writing device executes the method provided in the above-mentioned first aspect or various optional implementations of the first aspect.

[0030] Based on the implementation methods provided in the above aspects, this application can also be further combined to provide more implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a cross-sectional view of an optical storage medium provided in an embodiment of the present application;

[0032] FIG2 is a schematic diagram of a data reading and writing device for an optical storage medium provided in an embodiment of the present application;

[0033] FIG3 is a schematic diagram of an OPU provided in an embodiment of the present application;

[0034] FIG4 is a flow chart of a method for obtaining a compensation value of a position error of a servo light provided in an embodiment of the present application;

[0035] FIG5 is a schematic diagram of a position error compensation control loop provided in an embodiment of the present application;

[0036] FIG6 is a graph showing the amplitude-frequency characteristic of a transfer function of a tracking control circuit provided in an embodiment of the present application;

[0037] FIG7 is a schematic diagram of an illumination trajectory of a servo light provided in an embodiment of the present application;

[0038] FIG8 is a schematic diagram of a local position error of the same inner ring track provided by an embodiment of the present application;

[0039] FIG9 is a flow chart of a servo control method for an optical storage medium provided in an embodiment of the present application;

[0040] FIG10 is a control logic diagram of a tracking servo control provided by an embodiment of the present application;

[0041] FIG11 is a schematic diagram of a data writing process of an optical storage medium provided in an embodiment of the present application;

[0042] FIG12 is a comparison diagram of position errors of a servo light provided in an embodiment of the present application;

[0043] FIG13 is a schematic diagram of a servo control device for an optical storage medium provided in an embodiment of the present application;

[0044] FIG14 is a schematic structural diagram of a compensator provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0046] The present application relates to a data reading and writing device, which is used to read and / or write data (i.e., read and write data) on an optical storage medium. The optical storage medium is mounted on the data reading and writing device. The optical storage medium refers to a recording medium that records and reads data through laser irradiation. The optical storage medium may be a BD, CD, or digital versatile disc (DVD). The embodiments of the present application do not limit the type of optical storage medium 100.

[0047] For example, referring to FIG1 , which shows a cross-sectional view of an optical storage medium provided in an embodiment of the present application, optical storage medium 100 includes a protective layer 11, s recording layers 12, a reflective layer 13, and a guide layer 14 stacked in sequence. Where s is an integer greater than or equal to 1, and the present embodiment does not limit the value of s. Protective layer 11 is used to protect each recording layer 12.

[0048] When there are multiple recording layers 12, in order to distinguish each recording layer 12, each recording layer is numbered L1 to Ls in sequence according to the distance from the guide layer 14, where L1 is the recording layer 12 closest to the guide layer 14, and Ls is the recording layer 12 farthest from the guide layer 14.

[0049] The recording layer 12 is used to record data, and the way it records data is as follows: when the laser is irradiated onto the recording layer 12, the medium constituting the surface of the recording layer 12 undergoes physical or chemical changes, thereby changing the state of the medium. The recorded data is represented by the state of the medium. Taking the medium as a phase change material as an example, when the laser is irradiated onto the recording layer 12, the laser causes the state of part of the phase change material to change from an amorphous state to a crystalline state. The phase change material in the crystalline state can represent one type of recorded data, such as representing the data "1". The area in the recording layer 12 where the phase change material is not distributed can represent another type of data, such as representing the data "0". Of course, the phase change material in the crystalline state can also represent the data "0", and the area in the recording layer 12 where the phase change material is not distributed can represent the data "1".

[0050] Exemplarily, the recording layer 12 includes a land-in area and a data area. The land-in area is used to store metadata of the optical storage medium, including parameters related to each layer of the optical storage medium 100. The data area is used to record data and includes r tracks, where r is an integer greater than 1. The value of r may be the same or different for different optical storage media. The embodiment of the present application does not limit the value of r.

[0051] R tracks are arranged in a spiral form on the recording layer 12. By irradiating the tracks with laser light, data is recorded (i.e., written) along the tracks in the recording layer, so that the data is arranged in the form of tracks on the recording layer 12. When writing data to the tracks, the laser irradiation position is not necessarily located on the tracks, resulting in the tracks formed by the written data being different from the tracks on the recording layer. For ease of description, the tracks formed by the written data are referred to as data tracks, and the tracks on the recording layer are referred to as recording tracks or virtual tracks. In other embodiments, the recording layer 12 does not have recording tracks recorded, and the control unit reads and writes data on the recording layer 12 according to the parameters of the recording tracks provided by the metadata of the optical storage medium 100. It should be understood that the larger r is, the smaller the distance between the tracks (i.e., the track pitch), the greater the track density, and the greater the capacity of the recording layer 12. Conversely, the smaller r is, the larger the track pitch, the smaller the track density, and the smaller the capacity of the recording layer 12. To distinguish the tracks, the tracks are numbered T1 to T2 in order according to their radial distance from the center of the optical storage medium 100. r , where T1 is the track closest to the center, i.e. the first track, and T r is the orbit farthest from the center, i.e. the rth orbit.

[0052] Each track includes M sectors, where M is an integer greater than 1. Data is recorded on the track in sectors. The distribution of sectors in different optical storage media may be the same or different. The embodiment of the present application does not limit the value of M.

[0053] The surface of the guide layer 14 is provided with a guide track 141, also known as a guide groove. The guide track 141 is a position guide for recording the read and write positions. For example, if the guide track 141 is a pit string formed by pits and lands, the read and write positions are recorded by the combination of the pit and land lengths. For another example, if the guide track 141 is a wobble structure formed by grooves, the read and write positions are recorded by the wobble period of the wobble structure.

[0054] The guide layer 14 includes r guide tracks 141. The arrangement of the r guide tracks 141 is the same as that of the tracks in the recording layer 12. In order to distinguish the guide tracks 141, the guide tracks 141 are numbered T and T in sequence according to their radial distance from the center of the optical storage medium 100. (ref，1) ~T (ref，r) , where T (ref，1) The guide rail 141 closest to the center, that is, the first guide rail 141, T (ref，r) It is the track farthest from the center, ie, the rth guide track 141 .

[0055] Accordingly, the guide track 141 includes M sectors. For ease of description, the sectors in the guide track 141 are referred to as guide sectors, and the sectors of the tracks in the recording layer 12 are referred to as recording sectors. Each guide sector corresponds to a recording sector in each recording layer 11, and the position of each guide sector in the guide layer 1 is also the position of the corresponding recording sector in the recording layer 11. Since the arrangement of the guide track 141 is the same as the arrangement of the tracks in the recording layer 11, as shown in Figure 2, two laser beams are irradiated onto the storage medium through the same objective lens, wherein one laser beam irradiates the guide track 141 to guide the other laser beam to read and write data on the corresponding track in a certain recording layer 11.

[0056] To distinguish the laser light acting on the recording layer 12 from the laser light acting on the guide layer 14, the laser light acting on the recording layer 12 is referred to as read / write light. This light is used to read data from (i.e., write and read data to) the track on the recording layer 12. The laser light acting on the guide layer 14 is referred to as servo light. The read / write light and the servo light have different wavelengths. For example, the read / write light is blue light, while the servo light is red light. For ease of description, the wavelength of the read / write light is referred to as the first wavelength, and the wavelength of the servo light is referred to as the second wavelength.

[0057] In order to allow the servo light to penetrate s recording layers 12 and illuminate the guide layer 14, and prevent the read-write light from irradiating the guide layer 14, a reflective layer 13 is arranged between the guide layer 14 and the recording layer L1. The reflective layer 13 has the function of reflecting the laser of the first wavelength and transmitting the laser of the second wavelength. Therefore, when the read-write light is irradiated by the reflective layer 13, the reflective layer 13 reflects the read-write light to prevent the read-write light from irradiating the guide layer 14. When the servo light is irradiated by the reflective layer 13, the reflective layer 13 transmits the servo light, so that the servo light is irradiated to the guide track 141 of the guide layer 14 to guide the read-write light to read and write data in the recording layer 12. Based on this, the surface of the guide track 141 is called the reference surface (Ref) or the servo surface.

[0058] Next, the principle of the data reading and writing device reading and writing data on the optical storage medium is described in detail with reference to FIG2 :

[0059] FIG2 is a schematic diagram of a data reading and writing device for an optical storage medium provided in an embodiment of the present application. As shown in FIG2 , the data reading and writing device 200 includes a control unit 21, an optical processing unit (OPU) 22, a rotating stage 23, and a compensator 24. The rotating stage 23 is used to mount the optical storage medium 100. The control unit 21 controls the rotation of the rotating stage 23 so that the optical storage medium 100 rotates along with the rotating stage 23. The control unit 21, the OPU 22, and the compensator 24 are located in the laser driving circuit 203 in FIG1 .

[0060] During the rotation of the optical storage medium 100, the control unit 21 reads and writes data on the optical storage medium 100. For example, the control unit 21 controls the OPU 22 to emit read / write light and servo light toward the optical storage medium 100. Under the guidance of the servo light, the read / write light is irradiated onto the recording layer Lh of the optical storage medium 100 to read and write data on the recording layer Lh. The recording layer Lh is the hth recording layer 12 in the optical storage medium 100, where h is greater than or equal to 1 and less than or equal to s.

[0061] The following describes the process of reading and writing data on the optical storage medium 100 by taking the structural diagram of an OPU provided in an embodiment of the present application as shown in Figure 3 as an example.

[0062] As shown in Figure 3, OPU22 is provided with a read-write optical path and a servo optical path, wherein the read-write optical path is used to emit read-write light and transmit read-write reflected light to the optical storage medium 100, the read-write light is read light or write light, the write light is used to write data to the optical storage medium 100, the read light is used to read data from the optical storage medium 100, the read-write reflected light is the reflection light of the optical storage medium 100 to the read-write light, the read-write reflected light is the read reflection light or write reflection light, the read reflection light is the reflection light of the optical storage medium 100 to the read light, and the write reflection light is the reflection light of the optical storage medium 100 to the write light.

[0063] Taking the emission of read / write light to the optical storage medium 100 as an example, the transmission process of the read / write light on the read / write optical path is introduced as follows.

[0064] The control unit 21 controls the first laser emitter a1 to emit read / write light toward the first beam splitter a2. The first beam splitter a4 transmits the read / write light toward the compensation mirror group a3. Based on the focus servo control of the control unit 21, the compensation mirror group a3 performs focus compensation on the transmitted read / write light, allowing the read / write light to illuminate the recording layer Lh to be read / written in the optical storage medium 100. This compensates for the refractive index mismatch of the read / write light and transmits the corrected read / write light toward the dichroic mirror c1. The dichroic mirror c1 transmits the incident read / write light toward the objective lens c2. The objective lens c2 focuses the incident read / write light so that it illuminates the recording layer Lh to be read / written in the optical storage medium 100, forming a read / write light spot on the recording layer Lh. The recording layer Lh reflects the read / write light, generating read / write reflected light. After being reflected toward the objective lens c2, the reflected light passes through the objective lens c2, the dichroic mirror c1, and the compensation mirror group a3, and is transmitted to the first beam splitter a2. The first spectrometer a2 reflects the read / write reflected light toward the first photodetector integrated circuit (PDIC) a4. The first photodetector integrated circuit a4 detects the read / write reflected light to obtain a light sensing signal of the read / write light. The light sensing signal carries the position information of the light spot of the read / write light to indicate the irradiation position of the read / write light on the recording layer Lh.

[0065] 3 , the servo optical path is used to transmit servo light to the optical storage medium 100 and transmit the reflected light of the servo light (i.e., servo reflected light) from the optical storage medium 100. Taking the transmission of servo light to the optical storage medium 100 as an example, the transmission process of servo light on the servo optical path is described below.

[0066] The control unit 21 controls the second laser emitter b1 to emit servo light toward the second beam splitter b2. The second beam splitter b2 then emits the servo light toward the dichroic mirror c1. The dichroic mirror c1 transmits the incident servo light toward the objective lens c2. The objective lens c2 focuses the incident servo light so that it is directed onto the reference surface of the optical storage medium 100, forming a servo light spot on the reference surface. The reference surface reflects the servo light to generate servo reflected light. After being reflected toward the objective lens c2, the servo reflected light is transmitted through the objective lens c2 to the second beam splitter b2. The second beam splitter b2 reflects the servo reflected light toward the second photodetection integrated circuit b3. The second photodetection integrated circuit b3 is used to detect the servo reflected light and generate a light sensing signal of the servo light. The light sensing signal carries information about the position of the servo light spot, indicating the irradiation position of the servo light on the reference surface.

[0067] The first beam splitter a2 and the second beam splitter b2 can be polarization beam splitters (PBS), which are used to transmit or reflect the incident light according to the polarization direction of the incident light. The first laser emitter a1 and the second laser emitter b1 can both be laser diodes (LD), and the read-write light emitted by the first laser emitter a1 can be blue light. The servo light emitted by the second laser emitter b1 can be red light. Figure 3 is an example of a read-write optical path including a first laser emitter a1, and the first laser emitter a1 emits write light or read light. In other embodiments, the read-write optical path includes two first laser emitters a1, and the two first laser emitters a1 are used to emit write light or read light, respectively. Here, the embodiment of the present application does not limit the number of first laser emitters a1 in the read-write optical path. In other embodiments, the first laser emitter a1 may be replaced with a laser emitter array, so that the laser emitter array can emit a write light array or a read light array, thereby storing multiple data in the optical storage medium 200 or reading multiple data at a time, thereby increasing the data reading and writing efficiency of the data reading and writing device 200. The write light array includes multiple write lights, and the read light array includes multiple read lights.

[0068] FIG3 illustrates an example in which the read / write optical path and the servo optical path share some optoelectronic components (e.g., dichroic mirror c1 and objective lens c2). In this case, the read / write light and the servo light are coaxial. In other embodiments, the read / write optical path and the servo optical path are separate optical paths and do not share optoelectronic components.

[0069] During data reading and writing, the control unit 21 obtains the servo light's light sensing signal from the second photodetection integrated circuit b3, extracts the servo light's position information from this light sensing signal, and generates the servo light's focus position error and tracking position error based on this position information. The focus position error refers to the distance between the servo light spot position and the reference surface. The tracking position error refers to the radial distance between the servo light spot position and the target position, where the target position is the position on the reference surface corresponding to the position to be read or written on the recording layer Lh.

[0070] The control unit 21 generates a focus servo signal based on the focus position error and a focus control algorithm (e.g., an offline time-invariant control algorithm). Based on the focus servo signal, the control unit 21 performs focus servo control on the objective lens C2, which is shared by the read / write light and the servo light, so that the servo light can illuminate the reference surface. The focus servo signal is used to eliminate the focus position error. 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 via a torquer, and the control unit 21 controls the torquer to move the objective lens C2 in the focus direction of the optical storage medium 100 based on the focus servo signal, so that the servo light can illuminate the reference surface.

[0071] The control unit 21 generates a tracking servo signal based on the tracking position error and the tracking control algorithm. Based on the focus servo signal, the control unit 21 performs focus servo control on the objective lens C2, which is shared by the read / write light and the servo light, in the hope that the servo light can illuminate the target position on the reference surface. The tracking servo signal is used to eliminate the tracking position error. The tracking servo control process of the objective lens C2 can be as follows: the control unit 21 controls the torquer to move the objective lens C2 in the radial direction of the optical storage medium 100 based on the tracking servo signal, so that the servo light can illuminate the target position on the reference surface.

[0072] However, the tracking control algorithm used in related art cannot meet the tracking servo control accuracy requirements of the read / write light of a Blu-ray disc. This can easily cause newly written data tracks on the recording layer to intersect with adjacent data tracks when writing data to a Blu-ray disc. For example, in the related art position control method based on the adjacent track servo system (ATS), both the laser used for adjacent track servo (referred to as ATS light) and the writing light are irradiated onto the recording layer to be written. The tracking position error of the ATS light is compensated for the tracking position error of the servo light to generate a tracking servo signal. Based on the tracking servo signal, tracking servo control is performed on the objective lens so that the spot of the laser used for adjacent track servo (referred to as ATS light) tracks the spot of the writing light on the recording track to be written at the previous recording track to be written.

[0073] The tracking position error of the ATS light refers to the radial distance between the spot of the ATS light on the recording layer to be written and the spot of the writing light. The tracking position error of the ATS light is compensated for the tracking position error of the servo light by integrating the tracking position error of the ATS light using an integrator, adding the integration result to the tracking position error of the servo light to compensate for the tracking position error of the servo light, providing the compensated tracking position error to the tracking control circuit of the servo light, filtering the integration result using a filter to obtain a filtered result, using the filter as a feedforward controller of the tracking control circuit of the servo light, and performing feedforward control on the output of the tracking control circuit based on the filtered result to obtain a tracking servo signal.

[0074] However, due to the long calculation time and poor flexibility of the integrator in this compensation method, rapid positioning at any position during the tracking servo control process is not possible. Furthermore, the integrator can easily cause the tracking control circuit's response to continuously diverge, resulting in low tracking servo control accuracy and a tendency for data tracks to intersect when writing data to the optical storage medium. Furthermore, using a filter as a feedforward controller reduces the phase margin of the tracking control circuit. This low phase margin can also cause data tracks to intersect when writing data to the optical storage medium.

[0075] Based on this, the present application proposes a new position error compensation method to compensate for the tracking position error of the servo light during the reading and writing process. The compensation method is executed by a compensator in the data reading and writing device (such as the compensator 24 in Figure 2). The compensator is integrated in the control unit of the data reading and writing device, or is located in the data reading and writing device and independent of the control unit.

[0076] The compensator first detects multiple positions of the optical storage medium on the data read / write device to obtain compensation values ​​for these multiple positions, so as to subsequently compensate for the position error of the servo light at these positions on the reference surface. The multiple positions are multiple guide sectors, i.e., multiple guide positions, on the reference surface of the optical storage medium. The distribution of guide sectors for different optical storage media may be different or the same. Based on this, when any optical storage medium is installed in 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 of the optical storage medium to obtain compensation values ​​for these multiple positions, thereby ensuring that the compensation values ​​are applicable to the optical storage medium. Of course, this step can also be performed before or during data reading or writing on the optical storage medium, rather than when the optical storage medium is installed in the data read / write device or when the data read / write device starts the optical storage medium. The embodiments of the present application do not limit the timing of executing this step. In other embodiments, the compensator pre-stores compensation values ​​for multiple positions of at least one optical storage medium, and the compensator may not perform this step. When reading or writing data on any one of the at least one optical storage medium, the compensator uses the stored compensation values ​​for multiple positions of any one of the optical storage medium to compensate for the position error of the servo light during the reading and writing process.

[0077] For different optical storage media, the process of detecting multiple positions of the optical storage medium on the data reading and writing device to obtain compensation values ​​for these multiple positions is similar. The following takes any optical storage medium as an example to give a detailed introduction to the process. The process of obtaining multiple position compensation values ​​of other optical storage media can refer to the following introduction.

[0078] For example, FIG4 is a flow chart of a method for obtaining a compensation value of a position error of a servo light provided in an embodiment of the present application, and the method is executed by a compensator in a data reading and writing device.

[0079] 401. A compensator obtains a transfer function of a light tracking control circuit in a data reading and writing device.

[0080] The data read / write device is any of the aforementioned data read / write devices. The tracking control circuit is a loop within the data read / write device that performs tracking servo control on the servo light. The tracking servo control transfer function indicates how the output parameters of the tracking control circuit respond to changes in input parameters.

[0081] FIG5 is a schematic diagram of a position error compensation control loop provided by an embodiment of the present application. The control loop shown by the solid line in FIG5 is: in the tracking control circuit, the addition and subtraction unit G is used to perform subtraction operations on input parameters and output parameters; the tracking servo controller C is a module in the control unit of the data reading and writing device used to perform tracking servo control on the servo light; the torquer P is a torquer used to control the movement of the objective lens; the input parameters and output parameters of the tracking control circuit are the target position and the measured position, respectively. The target position is the guide sector corresponding to the position to be read or written in the optical storage medium, that is, the target irradiation position of the servo light; the measured position is the detected spot position of the servo light. The transfer function of the tracking control circuit is expressed as:

[0082] The mechanical characteristics of the control elements (such as C and P) of different tracking control circuits may be the same or different. In the case of different mechanical characteristics, the amplitudes of the transfer functions of different tracking control circuits may be different. For example, FIG6 shows an amplitude-frequency characteristic curve of the transfer function of a tracking control circuit provided in an embodiment of the present 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. In the case of different control elements, the amplitude of the transfer function of the tracking control circuit may be different by 1dB to 2dB.

[0083] Based on this, when the compensator provided in this application is applied to a data read / write device, the compensator obtains the transfer function of the cyclic servo loop in the data read / write device for subsequent use in calculating the compensation value. The compensator obtains the transfer function using the following method 1 or method 2.

[0084] Method 1: The compensator tests the transfer function of the tracking control circuit to obtain the transfer function.

[0085] Exemplarily, the compensator tests the transfer functions of each control element involved in the tracking control circuit. Based on the transfer data of each control element obtained through testing, the compensator generates a transfer function for the tracking control circuit according to the aforementioned transfer function expression for the tracking control circuit. The present embodiment of the present application does not limit the method for testing the transfer function.

[0086] By testing the transfer function of the tracking control circuit, the accurate transfer function of the tracking control circuit can be obtained. The compensation value calculated using the accurate transfer function is more accurate. Using the accurate compensation value to compensate for the position error on the tracking control circuit can increase the compensation effect of the position error, thereby improving the control accuracy of the tracking servo control.

[0087] Method 2: If the description file of the data reading and writing device includes 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 reading and writing device does not include the transfer function of the tracking control circuit, the function is obtained through method 1.

[0088] The description file is used to introduce the data reading and writing device, such as introducing the working principle of each control module in the data reading and writing device.

[0089] It should be understood that the transfer function of the tracking control circuit is used to calculate the compensation value, and the compensator can obtain the transfer function before calculating the compensation value (such as step 404), for example, obtaining the transfer function before the data reading and writing device leaves the factory. The transfer function can also be obtained when calculating the compensation value. Here, the embodiment of the present application does not limit the timing of obtaining the transfer function. Of course, if the compensator has the transfer function itself, the compensator does not need to obtain the transfer function by executing this step 401. For example, if the compensator pre-stores the transfer function of the tracking control circuit of at least one type of data reading and writing device, the compensator does not need to execute this step 401, and can use the transfer function of the tracking control circuit of the target type of data reading and writing device when calculating the compensation value, where the target type is the type of data reading and writing device where the compensator is located. Therefore, this step 401 is an optional step. Accordingly, step 401 is indicated as an optional step in a dotted box in Figure 4.

[0090] 402. The compensator detects multiple positions of the optical storage medium on the data reading and writing device to obtain multiple position errors of each of the multiple positions.

[0091] The optical storage medium is any optical storage medium installed in the data read / write device, such as a BD. The multiple positions are multiple guide sectors of the reference surface of the optical storage medium to be detected, i.e., ideal irradiation positions of the servo light during the detection process. The multiple position errors at any position are multiple tracking position errors of the servo light irradiated at the position, wherein the tracking position error is the radial distance between the spot position of the servo light and the position.

[0092] The multiple positions are located on at least one guide rail to be detected on the reference surface. The at least one guide rail may be all guide rails of the reference surface, or may be part of the guide rails of the reference surface. Since the process of detecting positions on each guide rail is similar, the process of detecting positions on part of the guide rail is used as an example to describe step 402. When detecting positions on all guide rails, the process of detecting positions on part of the guide rail can be referred to.

[0093] Taking the multiple positions of the partial guide tracks located in the reference as an example, for any layer in the reference surface and the recording layer, the compensator divides the r tracks in that layer into p inner tracks and q outer tracks. Here, p + q = r. Inner tracks refer to tracks close to the center of that layer, and outer tracks refer to tracks farther from the center of that layer. Exemplarily, the compensator defines tracks whose radial distance from the center of that layer is less than or equal to a first distance as inner tracks, and tracks whose radial distance from the center of that layer is greater than the first distance as outer tracks. Optionally, the first distance is the eccentricity of the optical storage medium during rotation. For example, the first distance ranges from 0.3 nm to 1 nm. For a track width of 160 nm, when the first distance is 0.3 nm, tracks 1 to 500 in that layer are all inner tracks. When the first distance is 1 nm, tracks 1 to 2000 in that layer are all inner tracks. In other embodiments, the first distance is not the eccentric distance, but a distance determined based on the eccentric distance or other factors, or the first distance is unrelated to the eccentric distance. Here, the embodiment of the present application does not limit the value range and value-taking method of the first distance, that is, it does not limit the number of inner ring tracks.

[0094] After determining the p inner ring tracks, the compensator uses the p inner ring tracks of the reference surface as guide tracks to be detected, detects multiple positions on the p inner ring tracks, and obtains multiple position errors of each of the multiple positions.

[0095] Since the detection method of each position error at each position is similar, for the convenience of description, the process of detecting a position error at each position on the p inner ring tracks is introduced as follows. The detection of other position errors at each position can refer to this process.

[0096] In a possible implementation, through the following steps 421 to 424 , multiple positions on the p inner orbits of the reference surface are detected to obtain a position error of the multiple positions.

[0097] Step 421: The compensator controls the rotating stage of the data reading and writing device so that the rotating stage drives the optical storage medium to rotate.

[0098] Step 422: The compensator controls the second laser emitter in the data reading and writing device to emit servo light to the optical storage medium.

[0099] In which, during the rotation of the optical storage medium, the compensator controls the second laser emitter to continuously emit servo light, so that the servo light passes through the servo optical path in the data reading and writing device and irradiates the reference surface of the optical storage medium, and controls the objective lens to emit the servo light to a guide track to be detected on the reference surface. As the optical storage medium rotates, the optical storage medium rotates one circle, and the servo light scans the guide track. During this period, the servo reflected light generated by the reference surface based on the servo light is transmitted along the servo optical path to the second cylindrical mirror of the servo optical path. The second photoelectric detection integrated circuit in the data reading and writing device detects multiple positions of the servo light on the guide track based on the servo reflected light on the second cylindrical mirror, and obtains a light sensing signal of the servo light. The light sensing signal carries information about the position of the servo light spot when scanning the guide track.

[0100] Step 423: During the rotation of the optical storage medium, the compensator controls the objective lens in the data reading and writing device so that the servo light moves in the radial direction of the optical storage medium.

[0101] Taking the test of multiple positions on p inner tracks as an example, in order from inside to outside or from outside to inside, each time the optical storage medium rotates one circle, the servo light scans the first guide track, and the compensator controls the objective lens in the data reading and writing device based on the track pitch, so that the irradiation position of the servo light jumps from the first guide track to the second guide track until the servo light scans all p inner tracks, wherein the first guide track is any inner track currently irradiated by the servo light among the p inner tracks, and the second guide track is the inner track adjacent to the first guide track among the p inner tracks. When the objective lens is adjusted in order from inside to outside, if the first guide track is T among the guide tracks among the p inner tracks, (ref，z) , then the second guide track is T among the guide tracks in the p inner tracks (ref，z+1) In the case of adjusting the objective lens in the order from outside to inside, if the first guide track is T among the guide tracks in the p inner ring tracks, (ref，z) , then the second guide track is T among the guide tracks in the p inner tracks (ref，z-1) , where T (ref，z) It refers to the zth guide track of the reference surface Ref, where z is greater than or equal to 1 and less than or equal to p.

[0102] Step 424: The compensator obtains a light sensing signal of the servo light from the second photodetection integrated circuit in the data reading and writing device, and obtains a position error of multiple positions on the p inner track based on the light sensing signal of the servo light.

[0103] Since the optical storage medium rotates one circle each time, the acquired light sensing signal carries the information of the spot position of the servo light when scanning a guide track, the objective lens is controlled through step 423 to realize the jumping of the servo light between the guide tracks. Accordingly, when the optical storage medium rotates p circles, the light sensing signal carries the information of the spot position of the servo light when scanning p inner ring tracks.

[0104] Assuming each inner track has M guide sectors, the compensator samples the light-sensing signals obtained after p rotations to obtain p*M positions of servo light. Each position information corresponds to a guide sector and indicates the position of the servo light spot irradiated onto the corresponding guide sector. Based on the position indicated by each piece of servo light position information and the corresponding guide sector, the position error of each guide sector is obtained. The position error of any guide sector is the radial distance between the position indicated by the corresponding servo light position information and the guide sector, i.e., a tracking position error of the servo light.

[0105] Therefore, through the process illustrated in steps 421-424 above, with the guide sector as the position to be detected on the inner track, the compensator can obtain a position error for multiple positions on the p inner tracks for every p rotations of the optical storage medium. Assuming that N position errors are required for each position, the compensator controls the optical storage medium to rotate N*p rotations. For every p rotations of the optical storage medium, the compensator executes steps 422-424. After the optical storage medium has rotated N*p rotations, the compensator obtains N position errors for each of the multiple positions. Alternatively, the compensator controls the optical storage medium to rotate N*p rotations, continuously executing step 422 during the rotation process and executing step 423 once after scanning each inner track. After the optical storage medium has rotated N*p rotations, the compensator executes step 424 to obtain N position errors for each of the multiple positions at once.

[0106] It should be understood that during the detection process, the servo light scans p inner tracks for every p rotations of the optical storage medium. During the scanning process, the servo light spot on the reference surface forms an illumination track of the servo light. For every N*p rotations of the optical storage medium, the servo light spot on the reference surface can form an illumination track of the servo light on the p inner tracks. The p inner tracks in a spiral form are the ideal tracks when the servo light scans the p inner tracks. For any illumination track of the servo light, the radial distance between the position of any guide sector in the ideal track and the illumination track is the position error of the servo light in that guide sector.

[0107] In order to further reflect the position error between the irradiation trajectory of the servo light and the ideal trajectory, refer to Figure 7, which shows an intention of the irradiation trajectory of the servo light provided in an embodiment of the present application. Figure 7 shows multiple irradiation trajectories of the servo light. These multiple irradiation trajectories are different, and the multiple position errors obtained by the servo light scanning the same guide sector multiple times are different.

[0108] For another example, FIG8 shows a schematic diagram of local position error for the same inner track according to an embodiment of the present application. FIG8 illustrates multiple position error curves (e.g., black curves in FIG8 ), each indicating the position error of the servo light in the 750th to 1100th guide sectors of the same inner track. FIG8 also shows that the multiple position errors obtained by the servo light scanning the same guide sector multiple times are different. This indicates that the position error of the servo light in each guide sector exhibits an oscillatory characteristic. Therefore, the compensator can extract a repeatable portion from the position error of the same guide sector and obtain a compensation value for the guide sector based on the repeatable portion (as described in steps 403 and 404 below). Subsequently, when reading and writing data in the recording sector corresponding to the guide sector, the repeatable portion can be compensated for in the tracking servo control of the servo light, thereby eliminating the repeatable portion of the position error and reducing the oscillation amplitude of the position error. This can reduce the radial offset between the servo light's illumination trajectory and the ideal trajectory, thereby improving the control accuracy of the tracking servo control.

[0109] 403. The compensator determines a repeatable runout (RRO) of each position based on the multiple position errors of each position, where the repeatable runout refers to a repeatable portion of the position error.

[0110] The repeatable error at any position includes not only the repeatable error but also the non-repeatable runout (NRRO), which is the non-repeatable portion of the position error. There is only one repeatable error at any position, and there are multiple non-repeatable errors at any position.

[0111] The repeatable error of any position is the average value of multiple position errors at any position, and the multiple non-repeatable errors of any position are the differences between the multiple position errors at any position and the repeatable error.

[0112] Taking any inner ring guide track as an example, assuming that there are M positions (i.e., guide sectors) on the inner ring guide track, the repeatable error of the j-th position among these M positions is recorded as RRO(j). The compensator obtains the average value of these N position errors based on the N position errors of the j-th position and the following RRO(j) formula, thereby obtaining the repeatable error RRO(j).

[0113] Among them, M is the total number of positions (i.e., guide sectors) on a certain inner circle guide track, N is the total number of position errors at the j-th position on the inner circle guide track, k is the sampling number of the position error, j is the number of a certain position on the inner circle guide track, PES(k, .j) is the position error of the j-th position on the inner circle guide track of the k-th sampling, that is, the k-th position error among the N position errors of the j-th position.

[0114] Assume that the j-th position has N non-repeatable errors, and record the j-th non-repeatable error among the N non-repeatable errors as NRRO(k, j). The compensator obtains the non-repeatable error NRRO(k, j) based on the repeatable error RRO(j), the position error PES(k, j) and the following NRRO(k, j) formula.

[0115] NRRO(k,j)=PES(k,j)-RRO(j),j=1,2,…,M,k=1,2,…,N

[0116] Using this method, the compensator can obtain the repeatable error and non-repeatable error at each position on the p inner guide tracks. To further illustrate the difference between repeatable error and position error at the same position, refer to the repeatable error curve shown by the white line in Figure 8. The repeatable error curve indicates the repeatable error of the servo light from the 750th to the 1100th guide sectors of the inner track. Clearly, the repeatable error at the same position is smaller than the position error at the same position.

[0117] 404. The compensator determines a compensation value for each position based on the repeatable error of each position and the transfer function.

[0118] The compensator uses the repeatable error at each position as the compensation value at each position, or uses the high-frequency portion of the repeatable error at each position as the compensation value at each position.

[0119] Exemplarily, the high-frequency portion of the repeatable error at each position is obtained through the following steps 441 and 442 .

[0120] Step 441: The compensator performs frequency domain transformation on the repeatable error at each position to obtain multiple frequency domain repeatable errors at each position, where the multiple frequency domain repeatable errors correspond to different frequencies.

[0121] A frequency domain repeatable error is the amplitude of the repeatable error at the corresponding frequency.

[0122] In one possible implementation, for any position, the compensator performs a Fourier transform on the repeatable error of the position to convert the repeatable error of the position from the time domain to the frequency domain, and obtains multiple repeatable errors of the position in the frequency domain interval (i.e., frequency domain repeatable errors).

[0123] Taking the jth position on a certain inner ring guide track as an example, the frequency domain repeatable error of the jth position is recorded as RRO f (j), the compensator converts the repeatable error RRO(j) into the frequency domain repeatable error RRO through the following Fourier transform formula f (j).

[0124] Among them, i=1, 2,..., N / 2, a i is a sine function The i-th constant coefficient, b i is the cosine function The i-th constant coefficient of RRO can also be f (j) Simplified to: RRO f (j) = Φ j *θ a ,in,

[0125] Taking j=1 as an example, the frequency domain repeatability error RRO of the first position on a certain inner track is f (1) is expressed as follows:

[0126] Taking j = 2 as an example, the frequency domain repeatability error RRO of the second position on a certain inner circle track is f (2) is expressed as follows:

[0127] The frequency domain interval can include multiple frequencies, and the compensator is based on the frequency domain repeatable error RRO f (j) formula, the frequency domain repeatability error RRO of the j-th position on a certain inner ring track at any frequency f can be calculated f (j).

[0128] Step 442: The compensator determines a compensation value for each position based on a high-frequency repeatable error among a plurality of frequency-domain repeatable errors at each position and the transfer function. The high-frequency repeatable error refers to a frequency-domain repeatable error whose corresponding frequency is greater than or equal to a frequency threshold.

[0129] Among them, the frequency threshold can be set according to the specific implementation scenario. For example, the frequency threshold is greater than or equal to 1500 Hz. Here, the embodiment of the present application does not limit the value range of the frequency threshold.

[0130] For any position, the compensator uses the frequency domain repeatable error of the position at the frequency threshold as the high-frequency repeatable error of the position, or uses the frequency domain repeatable error of the position at a frequency greater than the frequency threshold as the high-frequency repeatable error of the position.

[0131] Since the position error is a parameter in the time domain, in order to facilitate the subsequent compensation of the position error, for any position, the compensator converts the high-frequency repeatable error of that position from the time domain to the frequency domain, obtains the time domain repeatable error of that position, and determines the time domain repeatable error as the compensation value of that position.

[0132] In one possible implementation, the compensator uses the product of the high-frequency repeatable error at the location and the target frequency as the frequency-domain repeatable error compensation value, where the target frequency is greater than or equal to a frequency threshold. The compensator then performs an inverse Fourier transform on the frequency-domain repeatable error compensation value at the location to convert it from the frequency domain to the time domain, obtaining a time-domain repeatable error compensation value at the location at the target frequency, and uses the time-domain repeatable error compensation value as the compensation value for the location.

[0133] Taking the jth position on a certain inner ring guide track as an example, the compensator calculates the frequency domain repeatable error compensation value RRO of the jth position at frequency f according to the following inverse Fourier transform formula: f (j) Perform inverse Fourier transform to obtain the time domain repeatable error compensation value a at the jth position at frequency f if .

[0134] Where f0 refers to the reference frequency of the optical storage medium rotation speed, i refers to the multiple of the reference frequency f0, A i refers to the inverse Fourier real number amplitude, B i Refers to calculating the frequency domain repeatable error compensation value RRO f (j) is the real value of the transfer function of the tracking control loop, θ i It refers to the phase of the transfer function of the tracking control loop at frequency f, Φ i Refers to the frequency domain repeatable error compensation value RRO f (j) Phase at frequency f.

[0135] When determining the compensation value of the j-th position, take the target frequency as f and calculate the time domain repeatable error compensation value a of the j-th position at the target frequency according to the above inverse Fourier transform formula. if , with the time domain repeatable error compensation value a if is the compensation value of the jth position.

[0136] The high-frequency domain repeatable error is mainly caused by external disturbances. Excessive high-frequency domain repeatable error may cause the written data tracks to intersect. Therefore, the high-frequency domain repeatable error is an important factor affecting the control accuracy of the tracking servo control of the servo light. Based on steps 441-442, the high-frequency repeatable error can be extracted from the repeatable error of each position, and the high-frequency repeatable error of each position can be used as compensation for each position, so that when the position error of the servo light at each position is compensated based on the compensation value of each position, the high-frequency repeatable error in the position error of each position can be eliminated, and the oscillation amplitude of the position error in the high-frequency range can be reduced, thereby improving the control accuracy of the tracking servo control of the servo light and avoiding the intersection of the written data tracks.

[0137] It should be understood that the process shown in steps 402 to 404 is a process of obtaining compensation values ​​for multiple positions based on the transfer function and the detection results of the multiple positions of the optical storage medium.

[0138] 405. The compensator stores the compensation values ​​of the multiple positions.

[0139] Exemplarily, the compensator establishes a mapping relationship between the identifier of each position in the multiple positions and the compensation value of each position. For example, the compensator establishes a mapping relationship between the multiple positions and the compensation values ​​shown in Table 1 based on the identifier of each position in the multiple positions and the compensation of each position. As shown in Table 1, the identifier of each position includes the number of the guide track where the position is located (i.e., the track number) and the number of the position in the guide track. Taking the position as the guide sector as an example, the number of the position in the guide track is the sector number. Table 1 is an example of recording M positions of each guide track in p guide tracks, where T (ref，p) is the number of the pth guide track from the center of the guide layer. In this embodiment of the present application, the values ​​of p and M are not limited. As shown in Table 1, the position error compensation of each position is reflected in the compensation of the track width at each position. Therefore, the compensation value of each position is a percentage of the track width. (ref，1) Taking sector 1 of the recording layer as an example, when reading and writing data at the position corresponding to sector 1 of the recording layer, the track width of sector 1 is compensated by (-0.45%), where, as shown in Table 1, the track width of the first guide track is represented by w(1), and so on, the track width of the pth guide track is represented by w(p).

[0140] Table 1

[0141] As shown in Table 1, Table 1 also records the position of the data track generated when writing data after compensating for the position error of each position based on the compensation value of each position. In other embodiments, the position of the data track generated when writing data is not recorded in Table 1.

[0142] After establishing the mapping relationship between the multiple positions and the compensation values, the compensator stores the mapping relationship for subsequent query. For example, the compensator stores the mapping relationship in the memory of the data reading device itself or in the memory of the electronic device where the data reading and writing device is located. Here, the embodiment of the present application does not limit the storage location of the mapping relationship.

[0143] The memory used to store the mapping relationship may be a non-volatile random access memory and / or a volatile memory. Non-volatile memory may include read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may include random access memory (RAM). By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0144] In other embodiments, after the servo tracking control based on the compensation value is turned on for the servo light, the compensation values ​​of the multiple positions are obtained by detection, and there is no need to obtain the compensation values ​​of the multiple positions in advance. In this case, there is no need to store the compensation values ​​of the multiple positions. Therefore, step 405 is an optional step, and the dotted box in Figure 4 indicates that 405 is an optional step.

[0145] The method provided in the embodiment of the present application detects multiple positions of the optical storage medium to obtain compensation values ​​for these multiple positions, so that the obtained compensation values ​​can be applicable to the optical storage medium. When reading and writing data at these multiple positions of the optical storage medium subsequently, the position errors of the corresponding positions can be accurately compensated by appropriate compensation values ​​to reduce the position errors of the corresponding positions, thereby improving the control accuracy of the tracking servo control of the optical storage medium.

[0146] Next, the tracking servo control process based on compensation values ​​of multiple positions of any optical storage medium is described in detail below.

[0147] FIG9 is a flowchart of a servo control method for an optical storage medium provided in an embodiment of the present application, which is executed by a compensator in a data reading and writing device.

[0148] 901. A compensator obtains a compensation value corresponding to a position to be read or written in an optical storage medium.

[0149] The optical storage medium is any optical storage medium installed on the data reading and writing device where the compensator is located. The location to be read or written is any recording sector on any recording layer of the optical storage medium. The compensation value corresponding to the location to be read or written is the compensation value of the guide sector corresponding to the location in the optical storage medium. For ease of description, the location to be read or written is referred to as a target recording sector, the recording layer where the target recording sector is located is referred to as a target recording layer, the guide sector corresponding to the target recording sector is referred to as a target boot sector, and the guide track where the target boot sector is located is referred to as a target boot track.

[0150] When reading or writing data on the target recording sector, or before reading or writing data, the controller sets the target guide sector of the reference surface as the target position of the servo light. 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, then the target position is the first sector of the first guide track of the reference surface. For 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, then the target position is the first sector of the first guide track of the reference surface. It should be understood that the same recording sector of different recording layers corresponds to the same guide sector of the reference surface.

[0151] The control unit transmits the identifier of the target position to the compensator, instructing it to illuminate the target position with servo light. The compensator then compensates for the positional error between the servo light's illumination position and the target position. After obtaining the identifier of the target position, the compensator retrieves the compensation value for the target position from the corresponding relationship between multiple positions on the optical storage medium and compensation values ​​(as shown in Table 1). The compensation value for the target position is the compensation value corresponding to the position to be read or written.

[0152] In some embodiments, if the compensation value for the target position cannot be found, at least one position on a reference surface of the optical storage medium is detected to obtain the compensation value for the at least one position, where the at least one position includes the target position. The process of detecting at least one position on the reference surface of the optical storage medium to obtain the compensation value for the at least one position can be referred to the process described in steps 402 to 404 above and is not further described here.

[0153] 902. The compensator compensates for the position error of the servo light of the data reading / writing device based on the compensation value.

[0154] Exemplarily, the compensator subtracts the detected position of the servo light from the target position to obtain a position error of the servo light, and adds the compensation value obtained in step 901 to the position error to obtain a compensated position error.

[0155] 903. The compensator controls the objective lens of the data reading and writing device based on the compensated position error to read and write data at the position of the optical storage medium.

[0156] The objective lens is the objective lens shared by the read / write light and the servo light.

[0157] For example, the compensator generates a tracking servo signal based on the compensated position error, and the tracking servo signal is used to eliminate the compensated position error. The compensator sends the tracking servo signal to the torquer of the objective lens, and the torquer drives the objective lens to move in the radial direction of the optical storage medium based on the tracking servo signal, so that the servo light is irradiated to the compensated target position, and the read / write light is irradiated to the compensated read / write position, so as to read and write data at the compensated read / write position. The radial difference between the target position and the compensated target position is less than or equal to the compensation value of the target position, and the radial difference between the compensated read / write position and the position to be read / written is less than or equal to the compensation value of the target position.

[0158] The above description uses the example of a compensator controlling an objective lens based on a compensation value of a target position. In other embodiments, the compensator controls a tracking servo controller C in a tracking servo control circuit based on the compensation value of the target position to control the objective lens. Taking FIG5 as an example, an addition and subtraction unit G in the tracking control circuit subtracts the detected position of the servo light from the target position to obtain a position error of the servo light. The compensator sends the compensation value of the target position to the addition and subtraction unit G. The addition and subtraction unit G adds the compensation value to the position error to obtain a compensated position error, which is then sent to the tracking servo controller C. The tracking servo controller C generates a tracking servo signal based on the compensated position error, and sends the tracking servo signal to the torquer P. The torquer P controls the objective lens based on the tracking servo signal.

[0159] The above description is based on the example that the read / write light and the servo light share the same objective lens. In other embodiments, the read / write light and the servo light do not share the same objective lens, but use different objective lenses. The compensator controls the objective lenses of the read / write light and the servo light respectively based on the compensated position error in accordance with the above-mentioned method of controlling the objective lens.

[0160] In some embodiments, during the data reading and writing process, the compensator further determines whether written data in the target recording layer being read or written has been overwritten. If so, the compensator re-detects multiple locations in the optical storage medium to update compensation values ​​for the multiple locations. For example, after writing a first number of recording tracks in the target recording layer to obtain a first number of data tracks, the detector detects intersections of the first number of data tracks. If any data track in the first number of data tracks intersects with an adjacent data track, the data of the data track overwrites the data of the adjacent data track at the intersection. In this case, the compensator re-detects multiple locations in the optical storage medium to obtain new compensation values ​​for the multiple locations. The existing compensation values ​​for the multiple locations are updated to new compensation values. Based on the compensation values ​​corresponding to each location on the recording track corresponding to the data track, data is re-written to the recording track to obtain new data tracks, thereby preventing the new data tracks from intersecting with adjacent data tracks. The first number is greater than or equal to 1 and less than the total number of recording tracks in the recording layer. The first number is not limited in this embodiment of the present application.

[0161] The compensator detects the intersection of the first number of data tracks, including detecting the bit error rate of the first number of data tracks. If the bit error rate of any data track is greater than or equal to a bit error rate threshold, the data track intersects with the adjacent data track; if the bit error rate of the data track is less than the bit error rate threshold, the data track does not intersect with the adjacent data track. The bit error rate refers to the original bit error rate determined by the data reader / writer when reading data from the optical storage medium. The bit error rate threshold can be set based on the specific implementation scenario and is not limited here.

[0162] In other embodiments, if any data track in the first number of data tracks intersects with an adjacent data track, not all positions in the multiple positions in the optical storage medium are detected, but only the position corresponding to the data track in the multiple positions is detected to update the compensation value of the position corresponding to the data track, thereby reducing the number of positions to be detected, thereby enabling the compensation value to be updated quickly.

[0163] By updating the compensation value of the position, the accuracy of the compensation value is improved, so that the position error of the servo light can be accurately compensated during the tracking servo control of the servo light, which can further improve the control accuracy of the tracking servo control.

[0164] According to the method provided in an embodiment of the present application, since the position to be read or written in the optical storage medium corresponds to a guide sector on the reference surface of the optical storage medium, the position error between the irradiation position of the servo light on the reference surface and the guide sector is compensated for by using a compensation value corresponding to the position to be read or written, thereby reducing the current position error. Based on the reduced position error, the objective lens shared by the servo light and the read / write light is controlled to eliminate the compensated position error, thereby improving the control accuracy of the tracking servo control of the servo light. Due to the reduced position error of the servo light, under the guidance of the position of the servo light, the position error between the irradiation position of the read / write light and the position to be read or written is also reduced, so that the read / write light acts on the position to be read or written as much as possible. If data is written at the position to be read or written, the width of the track where the position to be read or written is located can be reduced to avoid writing to adjacent tracks, thereby preventing the track where the position to be read or written from intersecting with adjacent tracks. If data is read at the position to be read or written, the data recorded at that position can be read as much as possible, ensuring the accuracy of the read data.

[0165] The embodiment shown in FIG9 is introduced by taking the example of performing tracking servo control on the servo light based on the compensation value corresponding to the position when reading and writing data at any position of any track of any recording layer of the optical storage medium. Then, when reading and writing data at each position of each recording layer of the optical storage medium, the compensator can perform tracking servo control on the servo light based on the process shown in FIG9 , that is, the process shown in FIG9 can be used to perform tracking servo control on the servo light when reading and writing data on all tracks of the recording layer of the optical storage medium.

[0166] In other embodiments, the compensator uses the process shown in FIG9 to perform tracking servo control on the servo light only when reading or writing data to a portion of the tracks on the recording layer. Tracking servo control is not performed using the process shown in FIG9 when reading or writing data to other tracks on the recording layer. In other words, tracking servo control is performed based on the compensation value corresponding to the position to be read or written only when the position to be read or written is within a designated portion of the tracks on the optical storage medium.

[0167] Taking this part of the track as an example, which is the track near the center of the optical storage medium (i.e., the inner track), an embodiment of the present application provides a control logic diagram of tracking servo control as shown in Figure 10. As shown in Figure 10, when executing step 901, after obtaining the target position of the position to be read and written on the reference surface, the compensator determines whether the target position is located on the inner track of the reference surface. If it is located on the inner track, the compensator continues to execute steps 901-903. 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 and write data as much as possible at the position of the inner track. According to this method, when reading and writing data on the inner track, since the position error of the servo light is reduced, under the guidance of the position of the servo light, the position error between the irradiation position of the read / write light on the inner track of the recording layer and the position to be read / written is also reduced, so that the read / write light acts on the position to be read / written as much as possible. If data is written at the position to be read / written, the track width at the position to be read / written in the data track can be reduced to avoid writing to the adjacent data track. If data is read at a location to be read or written, the data recorded at that location can be read as much as possible to ensure the correctness of the read data.

[0168] As shown in Figure 10, if the target position is not located on the inner track of the reference surface, but on the outer track of the reference surface, the compensator does not execute steps 901-903, that is, the compensator does not compensate for the position error of the target position, thereby not interfering with the control process of the digital tracking control circuit, and the tracking control circuit performs tracking servo control based on the position error of the uncompensated target position. As described above, by compensating for the position error of the servo light on the inner track, the intersection of the data tracks of the recording layer can be avoided. If the tracking control circuit uses the inner track of the recording layer when performing tracking servo control on the servo light irradiated on the outer track, the servo control accuracy of the outer track can be improved when the data tracks of the inner circle of the recording layer do not intersect. For example, when reading and writing data to the outer track of the recording layer using a tracking control circuit based on the ATS position control method, the inner track of the recording layer that has already been written may be used.

[0169] Based on the above-described servo control method for optical storage media, the process of a data reading and writing device writing data to multiple recording layers of an optical storage medium is described as follows:

[0170] For example, Figure 11 is a schematic diagram of a data writing process of an optical storage medium provided in an embodiment of the present application. As shown in Figure 11, during the process of starting the system, when it is detected that the optical storage medium is placed on the rotating table of the data reading and writing device, the control unit of the data reading and writing device controls the rotating 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 focusing servo control circuit) in the data reading and writing device, controls the torquer of the objective lens, and moves the objective lens to the position corresponding to the guide area of ​​the servo surface.

[0171] The control unit starts the tracking servo control: controls the first laser emitter to emit reading light to the optical storage medium, controls the second laser emitter to emit servo light to the optical storage medium, controls the torquer of the objective lens to move so as to irradiate the reading light to the guide area of ​​the recording layer of the optical storage medium, and irradiates the servo light to the position corresponding to the guide area on the reference surface; obtains the light sensing signal of the servo light from the first photodetection integrated circuit, extracts the position of the light spot of the read / write light from the light sensing signal, determines the focusing error of the read / write light according to the position, and starts the focusing servo control of the reading light based on the focusing error, so that the read / write light is irradiated to the guide area of ​​the recording layer to obtain the reading reflected light; starts the tracking servo control of the servo light through the compensator, calculates the repeatable error of the servo light, generates the compensation value of the servo light on the inner ring track based on the repeatable error of the servo light, and starts the compensation of the servo light position error; decodes the metadata of the guide area from the light sensing signal of the read reflected light, and writes data to the recording layer of the optical storage medium based on the metadata.

[0172] Next, the control unit starts the writing process: assuming that the 1st to 500th tracks of the recording layer and the reference surface are inner tracks, after reading the write command for the recording layer L1, the intensity of the read-write light is adjusted so that the read-write light changes from reading light to writing light, and the tracking servo control of the servo light is turned on. Data is written to each track of the recording layer L1 in sequence from the inside to the outside. In the process of writing the 1st to 500th tracks of the recording layer L1, the position error compensation of the servo light is turned on; after writing the 500th track, data continues to be written to tracks other than the 500th track until all tracks of the recording layer L1 are written; when reading the write command for the recording layer L2, the first compensation mirror group is controlled so that the irradiation position of the writing light jumps from the recording layer L1 to the recording layer L2, and data is written to the recording layer L2 in the same manner as the writing to the recording layer L1 until the entire recording layer L2 is written, and so on until all recording layers of the optical storage medium are written.

[0173] In the embodiment shown in FIG11 , the data read / write device is described by way of example in which the data read / write device writes data sequentially to each recording layer of the optical storage medium in the order of the recording layers. In other embodiments, the data read / write device may write data to the recording layers in a manner other than the order of the recording layers, and may instead write data to the recording layer specified by the write command in accordance with the write command. In the embodiment shown in FIG12 , when writing to each recording layer, the data read / write device writes data sequentially to the tracks of the recording layer in the order from the inside to the outside. In other embodiments, the data read / write device may instead write data to the tracks of the recording layer in the order from the inside to the outside, and may instead write data to the track specified by the write command or to the location of the specified track in accordance with the write command.

[0174] In the case where the compensation value of the position error is obtained based on the high-frequency repeatable error, in order to further reflect the beneficial effects brought about by the tracking servo control of the servo light based on the compensated position error in the present application, refer to a position error comparison diagram of the servo light provided by an embodiment of the present application shown in Figure 12. The amplitude-frequency curve composed of "*" is used to reflect the change in the amplitude of the position error of the servo light in the frequency domain after the tracking servo control is performed based on the compensated position error (that is, the result of using the control scheme of the present application), and the black line amplitude-frequency curve is used to reflect the change in the amplitude of the position error of the servo light in the frequency domain after the tracking servo control is performed based on the uncompensated position error (that is, the control result of the tracking control circuit without interfering with the tracking control circuit. It can be seen from these two amplitude-frequency curves that after using the control scheme of the present application, the position error of the servo light is significantly reduced in the high-frequency range, the position error of the servo light is reduced by 30% to 50%, the width of the written track is reduced by 6nm to 9nm, and the squeezing between tracks can be reduced by 5% to 10%.

[0175] In an exemplary embodiment, a servo control device for an optical storage medium is further provided. The servo control device can be configured as the compensator in the previous embodiments, and is used to execute the method executed by the compensator. For example, FIG13 shows a schematic diagram of a servo control device for an optical storage medium provided in an embodiment of the present application. As shown in FIG13 , the servo control device 1300 includes:

[0176] An acquisition module 1301 is configured to acquire a compensation value corresponding to a position to be read or written in an optical storage medium;

[0177] A compensation module 1302 is configured to compensate for a position error of a servo light of a data reading and writing device based on a compensation value;

[0178] The control module 1303 is used to control the objective lens of the data reading and writing device based on the compensated position error, so as to read and write data at the position of the optical storage medium.

[0179] In a possible implementation, the location to be read or written is located on a track near the center of the optical storage medium.

[0180] In a possible implementation, the location to be read or written is located on a partial track in the optical storage medium.

[0181] In a possible implementation, the servo control device 1300 further includes:

[0182] The detection module is used to detect multiple positions of the optical storage medium to obtain compensation values ​​of the multiple positions.

[0183] In one possible implementation, the detection module includes:

[0184] a detection submodule, configured to detect a plurality of positions of the optical storage medium and obtain a plurality of position errors of each of the plurality of positions;

[0185] A first determination submodule is configured to determine a repeatable error of each position based on a plurality of position errors of each position, where the repeatable error refers to a repeatable portion of the position error;

[0186] The second determination submodule is configured to determine a compensation value for each position based on the repeatable error of each position.

[0187] In a possible implementation, the second determining submodule is configured to:

[0188] Perform frequency domain transformation on the repeatable error at each position to obtain multiple frequency domain repeatable errors at each position, where the multiple frequency domain repeatable errors correspond to different frequencies;

[0189] The compensation value of each position is determined based on a high-frequency repeatable error among a plurality of frequency-domain repeatable errors at each position, where the high-frequency repeatable error refers to a frequency-domain repeatable error whose corresponding frequency is greater than or equal to a frequency threshold.

[0190] In a possible implementation, the servo control device 1300 further includes:

[0191] An acquisition module 1301 is configured to acquire a transfer function of a tracking control circuit of a servo light in a data reading and writing device;

[0192] The detection module is further configured to obtain compensation values ​​for multiple positions based on the transfer function and detection results of multiple positions of the optical storage medium.

[0193] In a possible implementation, the detection module is further configured to:

[0194] The detection module is further configured to detect multiple positions in the optical storage medium again if written data is overwritten during the data reading and writing process, so as to update compensation values ​​of the multiple positions.

[0195] Based on the above various implementations, further combinations can be made to provide more implementations.

[0196] It should be understood that the servo control device 1300 corresponds to the compensator in the above-mentioned method embodiment, and the various modules in the servo control device 1300 and the above-mentioned other operations and / or functions are respectively various steps and methods implemented by the compensator in order to realize the method embodiment. For specific details, please refer to the above-mentioned method embodiment. For the sake of brevity, they will not be repeated here.

[0197] It should be understood that the division of the functional modules described above is merely an example of how the servo control device 1300 compensates for the position error of the servo light. In actual applications, the aforementioned functions can be assigned to different functional modules as needed, i.e., the internal structure of the servo control device 1300 can be divided into different functional modules to perform all or part of the functions described above. Furthermore, the servo control device 1300 provided in the above embodiment and the above method embodiment share the same concept. The specific implementation process is detailed in the above method embodiment and will not be further elaborated here.

[0198] In an exemplary embodiment, the compensator or servo control device 1300 mentioned above can be implemented by a processor, which is used to execute program code so that the data reading and writing device where the processor is located executes to implement the servo control method for optical storage media provided in the embodiment of the present application. Exemplarily, the processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor can be implemented in the form of at least one hardware of digital signal processing (DSP), field-programmable gate array (FPGA), and programmable logic array (PLA).

[0199] The present application also provides a compensator for use in a data reading and writing device, which is used to read and write data on an optical storage medium. The data reading and writing device is any of the data reading and writing devices described above. The compensator includes a processor, which is used to execute program code so that the compensator executes to complete the servo control method for the optical storage medium in the above embodiment. For example, FIG14 shows a schematic diagram of the structure of a compensator provided in an embodiment of the present application. The compensator 1400 includes one or more processors 1401 and one or more memories 1402. The one or more memories 1402 are coupled to the one or more processors 1401, and the one or more memories 1402 are used to store at least one program code. When the one or more processors execute the at least one program code, the compensator 1400 executes the above-mentioned related method steps to implement the servo control method for the optical storage medium in the above embodiment. The compensator 1400 can be a chip, a component, or a module.

[0200] In an exemplary embodiment, a computer-readable storage medium is also provided, such as a memory including at least one program code. The at least one program code can be executed by a processor in a data reading and writing device to implement the servo control method for an optical storage medium in the above embodiment. Exemplarily, the processor can be configured as the compensator mentioned above. For example, the computer-readable storage medium is a non-transitory computer-readable storage medium, such as a read-only memory (ROM), a random access memory (RAM), a compact disc read-only memory (CD-ROM), a magnetic tape, a floppy disk, and an optical data storage device.

[0201] The present application also provides a computer program product or computer program, which includes at least one program code stored in a computer-readable storage medium. A processor of a data reading / writing device reads and executes the at least one program code from the computer-readable storage medium, thereby enabling the data reading / writing device to implement the servo control method for an optical storage medium described in the above-mentioned embodiment. For example, the processor can be configured as the compensator described above.

[0202] Among them, the devices, equipment, computer-readable storage media, computer program products or chips provided in this embodiment are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0203] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0204] The units described as separate components may or may not be physically separate, and the components shown as units may be one physical unit or multiple physical units, that is, they may be located in one place or distributed in multiple places. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0205] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0206] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0207] In the description of this application, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, "at least one" means one or more, and "a plurality" means two or more. Words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not limit them to be necessarily different.

[0208] In this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0209] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A servo control method for an optical storage medium, characterized in that: The method comprises: Obtaining a compensation value of a high-frequency repeatable error corresponding to a position to be read or written in an optical storage medium, wherein the repeatable error refers to a repeatable portion of a position error of a servo light of a data reading or writing device; Based on the compensation value, compensating the position error; Based on the compensated position error, the objective lens of the data reading and writing device is controlled to read and write data at the position of the optical storage medium.

2. The method according to claim 1, characterized in that The step of obtaining a compensation value of a high-frequency repeatable error corresponding to a position to be read or written in the optical storage medium comprises: A compensation value for the high frequency repeatable error is determined based on the repeatable error measurement and the transfer function.

3. The method according to claim 1 or 2, characterized in that: The step of obtaining a compensation value of a high-frequency repeatable error corresponding to a position to be read or written in the optical storage medium comprises: Performing frequency domain transformation on the repeatable error of the position to be read or written to obtain multiple frequency domain repeatable errors, wherein the multiple frequency domain repeatable errors correspond to different frequencies; Based on a high-frequency repeatable error among the multiple frequency-domain repeatable errors, a compensation value of the position to be read or written is determined, wherein the high-frequency repeatable error refers to a frequency-domain repeatable error whose corresponding frequency is greater than or equal to a frequency threshold.

4. The method according to any one of claims 1 to 3, characterized in that The position to be read or written 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, characterized in that: The positions to be read and written are located in a part of the track in the optical storage medium.

6. The method according to any one of claims 1 to 4, characterized in that Before obtaining the compensation value corresponding to the position to be read or written in the optical storage medium, the method further includes: A plurality of positions of the optical storage medium are detected to obtain compensation values ​​of the plurality of positions.

7. The method according to claim 6, characterized in that The detecting a plurality of positions of the optical storage medium to obtain compensation values ​​of the plurality of positions comprises: Detecting a plurality of positions of the optical storage medium to obtain a plurality of position errors of each of the plurality of positions; Determine a repeatable error for each position based on the plurality of position errors for each position, wherein the repeatable error refers to a repeatable portion of the position error; Based on the repeatable error of each position, a compensation value for each position is determined.

8. The method according to claim 6 or 7, characterized in that: Before detecting a plurality of positions of the optical storage medium to obtain compensation values ​​of the plurality of positions, the method further comprises: Acquiring a transfer function of a tracking control circuit of the servo light in the data reading and writing device; Based on the transfer function and detection results of detecting multiple positions of the optical storage medium, compensation values ​​of the multiple positions are obtained.

9. The method according to any one of claims 6 to 8, characterized in that: The method further comprises: During the data reading and writing process, if the written data is overwritten, the multiple positions in the optical storage medium are detected again to update the compensation values ​​of the multiple positions.

10. A servo control device for an optical storage medium, characterized in that: The device comprises: An acquisition module, used to acquire a compensation value of a high-frequency repeatable error corresponding to a position to be read or written in the optical storage medium, wherein the repeatable error refers to a repeatable portion of a position error of a servo light of a data reading or writing device; A compensation module, used for compensating the position error based on the compensation value; The control module is used to control the objective lens of the data reading and writing device based on the compensated position error, so as to read and write data at the position of the optical storage medium.

11. The device according to claim 10, characterized in that The step of obtaining a compensation value of a high-frequency repeatable error corresponding to a position to be read or written in the optical storage medium comprises: A compensation value for the high frequency repeatable error is determined based on the repeatable error measurement and the transfer function.

12. The device according to claim 10 or 11, characterized in that The step of obtaining a compensation value of a high-frequency repeatable error corresponding to a position to be read or written in the optical storage medium comprises: Performing frequency domain transformation on the repeatable error of the position to be read or written to obtain multiple frequency domain repeatable errors, wherein the multiple frequency domain repeatable errors correspond to different frequencies; Based on a high-frequency repeatable error among the multiple frequency-domain repeatable errors, a compensation value of the position to be read or written is determined, wherein the high-frequency repeatable error refers to a frequency-domain repeatable error whose corresponding frequency is greater than or equal to a frequency threshold.

13. The device according to any one of claims 10 to 12, characterized in that The position to be read or written is located on a track close to the center of the optical storage medium.

14. The device according to any one of claims 10 to 12, characterized in that The positions to be read and written are located in a part of the track in the optical storage medium.

15. The device according to any one of claims 10 to 14, characterized in that The device also includes: The detection module is used to detect multiple positions of the optical storage medium to obtain compensation values ​​of the multiple positions.

16. The device according to claim 15, characterized in that The detection module comprises: A detection submodule, configured to detect a plurality of positions of the optical storage medium to obtain a plurality of position errors of each of the plurality of positions; A first determination submodule, configured to determine a repeatable error of each position based on a plurality of position errors of each position, wherein the repeatable error refers to a repeatable portion of the position error; The second determination submodule is used to determine the compensation value of each position based on the repeatable error of each position.

17. The device according to claim 15 or 16, characterized in that The acquisition module is further used to acquire the transfer function of the tracking control circuit of the servo light in the data reading and writing device; The detection module is further used to obtain compensation values ​​of the multiple positions based on the transfer function and the detection results of the multiple positions of the optical storage medium.

18. The device according to any one of claims 15 to 17, characterized in that The detection module is also used for: During the data reading and writing process, if the written data is overwritten, the multiple positions in the optical storage medium are detected again to update the compensation values ​​of the multiple positions.

19. A data reading and writing device for an optical storage medium, characterized in that: The data reading and writing device comprises a processor, and the processor is used to execute program code, so that the data reading and writing device executes the method according to any one of claims 1 to 9.

20. A compensator used in a data reading and writing device, characterized in that: The data reading and writing device is used to read and write data on an optical storage medium. The compensator includes a processor, and the processor is used to execute program code so that the compensator executes the method as claimed in any one of claims 1 to 9.

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