Servo control method and device for optical storage medium and data read-write device

Abstract

The invention discloses a servo control method and device for an optical storage medium and a data read-write device, and belongs to the technical field of optical storage. According to the method, aiming at the position error between the irradiation position of the servo light on the reference surface and the guide sector, the position error of the servo light is compensated through the compensation value corresponding to the position to be read and written in the optical storage medium so as to reduce the current position error, and the position error of the servo light can be read and written 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, so that the control precision of tracking servo control of the servo light is improved.

Description

Technical Field

[0001] The present application relates to the field of optical storage technology, and in particular to a servo control method and device for an optical storage medium and a data reading and writing device. Background Art

[0002] 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, blue-ray discs (BDs) and compact discs (CDs).

[0003] When writing to an optical storage medium, the writing light and the servo light are focused respectively onto the recording layer and the servo layer of the optical storage medium 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 subjected to tracking servo control 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, and the written data can be arranged in the form of a track on the recording layer.

[0004] At present, the control accuracy of the tracking servo control of servo light (such as red light) is about 18 nanometers (nanometer, nm). However, the control accuracy of the tracking servo control required by high-density optical storage media is generally higher than 18nm. High-density optical storage media refers to optical storage media in which the number of tracks in the recording layer exceeds the threshold number, that is, optical storage media with a large number of tracks in the recording layer.

[0005] Taking a high-density Blu-ray disc as an example, the writing light of the Blu-ray disc requires a tracking servo control accuracy of 9nm. It can be seen that the current tracking servo control control accuracy of the servo light is far from meeting the requirements of the writing light of the Blu-ray disc. When writing data to the Blu-ray disc, due to the insufficient control accuracy of the tracking servo control of the servo light, the newly written data track on the recording layer intersects with the written adjacent data track (i.e., track squeezing occurs), causing the newly written data to cover the written data on the adjacent data track, resulting in the loss of the written data on the adjacent data track. Therefore, a servo control method for optical storage media is urgently needed to improve the control accuracy of the tracking servo control of the servo light. Summary of the invention

[0006] The embodiments of the present application provide a servo control method, device and data reading and writing device for an optical storage medium, which can improve the control accuracy of tracking servo control of servo light. The technical solution is as follows:

[0007] In a first aspect, a servo control method for an optical storage medium is provided, the method comprising 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 or writing device; and then, based on the compensated position error, controlling an objective lens of the data reading or writing device to read or write data at the position of the optical storage medium.

[0008] The method compensates for the position error of the servo light by using 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.

[0009] In a possible implementation, the position to be read or written is located on a track close to the center of the optical storage medium.

[0010] 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 a compensation value corresponding to the position to be read or written on the track near the center. Thus, under the guidance of the position of the servo light, data can be written as much as possible on the track near the center to be read or written, and the track width of the written data track at the position to be read or written can be reduced to avoid writing to adjacent data tracks, thereby making the data tracks written on the track near the center non-intersecting.

[0011] In a possible implementation, the position to be read or written is located in a partial track in 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 a compensation value corresponding to the position to be read and written on a portion of the track. Thus, 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, thereby making the data tracks written on this portion of the track non-intersecting.

[0013] 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 ​​of the multiple positions.

[0014] 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. 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.

[0015] 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 for each position, determining a repeatable error for each position, where the repeatable error refers to the repeatable part of the position error; then, based on the repeatable error for each position, determining a compensation value for each position.

[0016] 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. Therefore, 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.

[0017] In one possible implementation, the process of determining the compensation value of each position based on the repeatable error of each position includes the following steps: first, performing a frequency domain transform on the repeatable error of each position to obtain multiple frequency domain repeatable errors of each position; then, determining the compensation value of each position based on the high-frequency repeatable error in the multiple frequency domain repeatable errors of 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.

[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. Therefore, 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, reducing the oscillation amplitude of the position error in the high-frequency range and improving the control accuracy of the tracking servo control.

[0019] In one possible implementation, before detecting multiple positions of the optical storage medium to obtain compensation values ​​for the multiple positions, the method also 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 detecting multiple positions of the optical storage medium.

[0020] 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 in the tracking control circuit can increase the compensation effect of the position error, thereby improving the control accuracy of the tracking servo control.

[0021] In a possible implementation, the method further includes the following steps: during the data reading and writing process, if the written data is overwritten, multiple positions in the optical storage medium are detected again to update the compensation values ​​of the multiple positions.

[0022] Based on the above possible implementation method, the 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 a new data track to avoid the new data track from intersecting with the adjacent data track.

[0023] In a second aspect, a servo control device for optical storage media is provided, which is used to execute the servo control method for optical storage media. Specifically, the servo control device includes a functional module for executing the method provided in the first aspect or any optional manner of the first aspect.

[0024] In a third aspect, a data reading and writing device for an optical storage medium is provided, the data reading and writing device comprising 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 manner of the first aspect.

[0025] 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.

[0026] 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 a method provided in the first aspect or any optional method of the first aspect.

[0027] In a 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.

[0028] Based on the implementations provided in the above aspects, this application can also be further combined to provide more implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a cross-sectional view of an optical storage medium provided in an embodiment of the present application;

[0030] Figure 2 is a schematic diagram of a data reading and writing device for an optical storage medium provided in an embodiment of the present application;

[0031] Figure 3 is a schematic diagram of an OPU provided in an embodiment of the present application;

[0032] Figure 4 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;

[0033] Figure 5 is a schematic diagram of a position error compensation control loop provided in an embodiment of the present application;

[0034] Figure 6 is an amplitude-frequency characteristic curve diagram of a transfer function of a tracking control circuit provided in an embodiment of the present application;

[0035] Figure 7 This is an intended illumination trajectory of a servo light provided in an embodiment of the present application;

[0036] Figure 8 It is a schematic diagram of a local position error of the same inner ring track provided in an embodiment of the present application;

[0037] Fig. 9 is a flow chart of a servo control method for an optical storage medium provided in an embodiment of the present application;

[0038] Fig.10 is a control logic diagram of a tracking servo control provided by an embodiment of the present application;

[0039] Fig.11 is a schematic diagram of a data writing process of an optical storage medium provided by an embodiment of the present application;

[0040] Fig.12 is a position error comparison diagram of a servo light provided in an embodiment of the present application;

[0041] Fig.13 is a schematic diagram of a servo control device for an optical storage medium provided in an embodiment of the present application;

[0042] Fig.14 It is a structural schematic diagram of a compensator provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0044] The present application relates to a data reading and writing device, which is used to read data and / or write data (i.e., read and write data) on an optical storage medium, wherein the optical storage medium is installed on the data reading and writing device, and the optical storage medium refers to a recording medium that records and reads data by laser irradiation. The optical storage medium is, for example, a BD, a CD, or a digital versatile disc (DVD). Here, the embodiment of the present application does not limit the type of the optical storage medium 100.

[0045] For example, see Figure 1 The cross-sectional view of an optical storage medium provided by an embodiment of the present application is shown, and the 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. Wherein s is an integer greater than or equal to 1, and the embodiment of the present application does not limit the value of s. The protective layer 11 is used to protect each recording layer 12.

[0046] 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.

[0047] The recording layer 12 is used to record data, and the way of recording data is as follows: when the laser is irradiated to the recording layer 12, the medium constituting the surface of the recording layer 12 will undergo physical or chemical changes, changing the state of the medium. The recorded data is characterized by the state of the medium. Taking the medium as a phase change material as an example, when the laser is irradiated to the recording layer 12, the laser causes the state of part of the material in the phase change material to be converted from an amorphous state to a crystalline state. The phase change material in the crystalline state can represent one type of data, such as representing 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 data "0". Of course, the phase change material in the crystalline state can also represent data "0", and the area in the recording layer 12 where the phase change material is not distributed can represent data "1".

[0048] Exemplarily, the recording layer 12 includes a land in area and a data area, wherein the land in area is used to store metadata of the optical storage medium, and the metadata includes relevant parameters of each layer of the optical storage medium 100. The data area is used to record data, and the data area includes r tracks, where r is an integer greater than 1, and the value of r of different optical storage media may be the same or different, and the embodiment of the present application does not limit the value of r.

[0049] r tracks are arranged in a spiral form on the recording layer 12. By irradiating the track with laser, data is recorded on the recording layer along the track (i.e., writing data), so that the data is arranged in the form of tracks on the recording layer 12. When writing data to the track, the irradiation position of the laser is not necessarily located on the track, resulting in the track formed by the written data being different from the track of the recording layer. For ease of description, the track formed by the written data is referred to as a data track, and the track of the recording layer is referred to as a recording track or a virtual track. In other embodiments, the recording layer 12 does not have a recording track recorded, and the control unit reads and writes data on the recording layer 12 according to the parameters of the recording track 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 larger the track density, and the larger 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. In order to distinguish each track, each track is numbered T in sequence according to the distance from the center of the optical storage medium 100 in the radial direction. 1 ~T r , where T 1 is the track closest to the center, i.e. the first track, T r is the orbit farthest from the center, i.e. the rth orbit.

[0050] Each track includes M sectors, where M is an integer greater than 1. Data is recorded in sectors on the track. 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.

[0051] The surface of the guide layer 14 is provided with a guide track 141, which is also called a guide groove. The guide track 141 is a position guide for recording the read and write positions. For example, the guide track 141 is a pit string formed by pits and lands, and the read and write positions are recorded by the combination of the lengths of the pits and the lands. For another example, the guide track 141 is a wobble structure formed by grooves, and the read and write positions are recorded by the wobble period of the wobble structure.

[0052] 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 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) is the guide track 141 closest to the center, that is, the first guide track 141, T (ref，r) It is the track farthest from the center, namely the rth guide track 141 .

[0053] Accordingly, the guide track 141 includes M sectors. For the convenience of description, the sectors in the guide track 141 are called guide sectors, and the sectors in the track in the recording layer 12 are called 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 track in the recording layer 11, as shown in FIG. Figure 2 Two laser beams are irradiated onto the storage medium through the same objective lens, wherein one laser beam is irradiated onto the guide track 141 to guide the other laser beam to read and write data on a track corresponding to a certain recording layer 11 .

[0054] In order to distinguish the lasers acting on the recording layer 12 and the guide layer 14, the laser acting on the recording layer 12 is called read / write light, which is used to read data or data (i.e., read / write data) on the track of the recording layer 12, and the laser acting on the guide layer 14 is called servo light. The read / write light and the servo light have different wavelengths, for example, the read / write light is blue light, and the servo light is red light. For the convenience of description, the wavelength of the read / write light is called the first wavelength, and the wavelength of the servo light is called the second wavelength.

[0055] 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 to the reflective layer 13, the reflective layer 13 reflects the read-write light to prevent the read-write light from irradiating to the guide layer 14. When the servo light is irradiated to 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 a reference surface (Ref) or a servo surface.

[0056] Next, combine Figure 2 The principle of the data reading and writing device reading and writing data on the optical storage medium is introduced in detail as follows:

[0057] Figure 2 is a schematic diagram of a data reading and writing device for an optical storage medium provided in an embodiment of the present application, such as Figure 2 As shown, the data reading and writing device 200 includes a control unit 21, an optical processing unit (OPU) 22, a rotating table 23 and a compensator 24. The rotating table 23 is used to install the optical storage medium 100. The control unit 21 controls the rotating table 23 to rotate so that the optical storage medium 100 rotates with the rotating table 23. The control unit 21, the OPU 22 and the compensator 24 are located Figure 1 The laser driving circuit 203 in.

[0058] 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 to the optical storage medium 100. Under the guidance of the servo light, the read-write light is irradiated to 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, and h is greater than or equal to 1 and less than or equal to s.

[0059] Combine the following Figure 3 Taking the structural diagram of an OPU provided in the embodiment of the present application as an example, the process of reading and writing data on the optical storage medium 100 is introduced as follows.

[0060] like Figure 3 As shown, 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 to the optical storage medium 100 and transmit read / write reflected light, 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 reading reflected light or the writing reflected light, the reading reflected light is the reflection light of the optical storage medium 100 to the read light, and the writing reflected light is the reflection light of the optical storage medium 100 to the write light.

[0061] 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.

[0062] The control unit 21 controls the first laser emitter a1 to emit the read / write light to the first beam splitter a2, and the first beam splitter a4 transmits the read / write light to the compensation mirror group a3. The compensation mirror group a3 performs focusing compensation on the transmitted read / write light based on the focusing servo control of the control unit 21, so that the read / write light can irradiate the recording layer Lh to be read / written in the optical storage medium 100, and correct the refractive index mismatch of the read / write light, and emit the corrected read / write light to the dichroic mirror c1. The dichroic mirror c1 transmits the incident read light to the objective lens c3. The objective lens c2 focuses the incident read / write light to irradiate the read / write light to the recording layer Lh to be read / written in the optical storage medium 100, and forms a light spot of the read / write light on the recording layer Lh. The recording layer Lh reflects the read / write light to obtain read / write reflected light. After the read / write reflected light is reflected to the objective lens c2, it is sequentially transmitted to the first beam splitter a2 through the objective lens c2, the dichroic mirror c1 and the compensation mirror group a3. The first beam splitter a2 reflects the read / write reflected light in the direction of 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.

[0063] like Figure 3 As shown, the servo optical path is used to transmit servo light to the optical storage medium 100 and transmit the reflected light of the optical storage medium 100 to the servo light (ie, servo reflected light). 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 as follows.

[0064] The control unit 21 controls the second laser emitter b1 to emit servo light to the second beam splitter b2, and the second beam splitter b2 emits servo light to the dichroic mirror c1, and the dichroic mirror c1 transmits the incident servo light to the objective lens c2. The objective lens c2 focuses the incident servo light to irradiate the servo light to the reference surface of the optical storage medium 100, forming a light spot of the servo light on the reference surface. The reference surface reflects the servo light to obtain servo reflected light, and after the servo reflected light is reflected to the objective lens c2, it is transmitted to the second beam splitter b2 through the objective lens c2. The second beam splitter b2 reflects the servo reflected light in the direction of the second photodetection integrated circuit b3, and the second photodetection integrated circuit b3 is used to detect the servo reflected light to obtain a light sensing signal of the servo light, which carries the position information of the light spot of the servo light to indicate the irradiation position of the servo light on the reference surface.

[0065] The first beam splitter a2 and the second beam splitter b2 may 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 may both be laser diodes (LD), and the read / write light emitted by the first laser emitter a1 may be blue light. The servo light emitted by the second laser emitter b1 may be red light. Figure 3 The example in which the read-write optical path includes a first laser emitter a1 is shown, 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 can also be replaced by a laser emitter array, so that the laser emitter array can emit a write light array or a read light array, so that multiple data can be stored in the optical storage medium 200 or multiple data can be read at one time, increasing the data read-write efficiency of the data read-write device 200. The write light array includes multiple write lights, and the read light array includes multiple read lights.

[0066] Above Figure 3 The example in which the read / write optical path and the servo optical path share some photoelectric components (such as the dichroic mirror c1 and the objective lens c2) is used for illustration. 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 photoelectric components.

[0067] During the data reading and writing process, the control unit 21 obtains the light sensing signal of the servo light from the second photodetection integrated circuit b3, extracts the position information of the servo light from the light sensing signal, and generates the focus position error and tracking position error of the servo light based on the position information, wherein the focus position error refers to the distance between the spot position of the servo light and the reference surface. The tracking position error is the distance between the spot position of the servo light and the target position in the radial direction, wherein the target position is the position on the reference surface corresponding to the position to be read and written on the recording layer Lh.

[0068] The control unit 21 generates a focus servo signal based on the focus position error and a focus control algorithm (such as an offline time-invariant control algorithm), and performs focus servo control on the objective lens c2 shared by the read-write light and the servo light based on the focus servo signal, so as to hope that the servo light can irradiate the reference surface. The focus servo signal is used to eliminate the focus position error, and the process of performing focus servo control on the objective lens c2 can be: the control unit 21 is connected to the objective lens c2 through 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 irradiate the reference surface.

[0069] The control unit 21 generates a tracking servo signal based on the tracking position error and the tracking control algorithm, and performs focusing servo control on the objective lens c2 shared by the read / write light and the servo light based on the focusing servo signal, so as to hope that the servo light can irradiate the target position of the reference surface. The tracking servo signal is used to eliminate the tracking position error, and the process of performing tracking servo control on the objective lens c2 can be: the control unit 21 controls the torquer to drive the objective lens c2 to move in the radial direction of the optical storage medium 100 based on the tracking servo signal, so that the servo light can irradiate the target position on the reference surface.

[0070] However, the control accuracy of the tracking control algorithm used in the related art cannot meet the control accuracy requirements of the tracking servo control of the read-write light of the Blu-ray Disc. When writing data to the Blu-ray Disc, it is easy to make the newly written data track of the recording layer intersect with the adjacent data track. Take the position control method based on the adjacent track servo system (ATS) in the related art as an example. In the ATS technology, the laser used for adjacent track servo (called ATS light) and the writing light are both irradiated on the recording layer to be written, and the tracking position error of the ATS light is compensated to the tracking position error of the servo light to generate a tracking servo signal. Based on the tracking servo signal, the tracking servo control is performed on the objective lens so that the spot of the laser used for adjacent track servo (called ATS light) tracks the spot of the writing light on the recording track to be written in the previous recording track of the recording track to be written.

[0071] 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 to the tracking position error of the servo light by integrating the tracking position error of the ATS light through 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 through a filter to obtain a filtering result, using the filter as a feedforward controller of the tracking control circuit of the servo light, and performing feedforward control on the output result of the tracking control circuit based on the filtering result to obtain a tracking servo signal.

[0072] However, in the above compensation method, due to the characteristics of the integrator such as long calculation time and poor flexibility, the fast positioning of any position cannot be achieved during the tracking servo control process, and the integrator easily causes the response of the tracking control circuit to diverge continuously, resulting in low control accuracy of the tracking servo control, and easily causing the written data tracks to intersect when writing data to the optical storage medium. In addition, the filter is used as a feedforward controller, and the filter reduces the phase margin of the tracking control circuit. When writing data to the optical storage medium, the low phase margin of the tracking control circuit will also cause the written data tracks to intersect.

[0073] 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 composed of a compensator (such as Figure 2 The compensator 24 is executed, and 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 is independent of the control unit.

[0074] The compensator first detects multiple positions of the optical storage medium on the data reading and writing device to obtain compensation values ​​of the multiple positions, so as to subsequently compensate for the position error of the servo light at the position on the reference surface. The multiple positions are multiple guide sectors on the reference surface of the optical storage medium, that is, multiple guide positions. The distribution of guide sectors of different optical storage media may be different or the same. Based on this, when any optical storage medium is installed on the data reading and writing device or when the data reading and writing device starts the optical storage medium, the compensator performs the step of detecting multiple positions of the optical storage medium to obtain compensation values ​​of the multiple positions, so that the compensation values ​​can be applied to the optical storage medium. Of course, this step can also be performed before or when the optical storage medium reads and writes data instead of when the optical storage medium is installed on the data reading and writing device or when the data reading and writing device starts the optical storage medium. Here, the embodiment of the present application does not limit the execution timing of this step. In other embodiments, if the compensator pre-stores compensation values ​​for multiple positions of at least one optical storage medium, 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 may use the stored compensation values ​​for multiple positions of the any one optical storage medium to compensate for the position error of the servo light during the data reading and writing process.

[0075] 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 the compensation values ​​of these multiple positions is similar. Taking any optical storage medium as an example, the process is described in detail as follows. The process of obtaining the compensation values ​​of multiple positions of other optical storage media can refer to the following introduction.

[0076] For example, Figure 4 It 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.

[0077] 401. A compensator obtains a transfer function of a light tracking control circuit in a data reading and writing device.

[0078] The data reading and writing device is any of the data reading and writing devices described above. The tracking control circuit is a loop in the data reading and writing device for performing tracking servo control on the servo light. The transfer function of the tracking servo control is used to indicate the response of the output parameter of the tracking control circuit to the change of the input parameter.

[0079] like Figure 5 The schematic diagram of a position error compensation control loop provided by an embodiment of the present application is shown in FIG. Figure 5The control loop shown by the solid line is that in the tracking control circuit, the addition and subtraction unit G is used to perform subtraction operations on the 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 and 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:

[0080]

[0081] The mechanical properties 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 properties, the amplitudes of the transfer functions of different tracking control circuits may be different. For example Figure 6 The amplitude-frequency characteristic curve diagram of the transfer function of a tracking control circuit provided by an embodiment of the present application is shown, where the amplitude-frequency curve 601 shows the amplitude variation of the transfer function at different frequencies, and the phase-frequency curve 602 shows the phase variation 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.

[0082] Based on this, when the compensator provided in the present application is applied to a data reading and writing device, the compensator obtains the transfer function of the cyclic servo loop in the data reading and writing device for subsequent use in calculating the compensation value. The compensator obtains the transfer function by the following method 1 or method 2.

[0083] Method 1: The compensator tests the transfer function of the tracking control circuit to obtain the transfer function.

[0084] Exemplarily, the compensator tests the transfer function of each control element involved in the tracking control circuit, and generates the transfer function of the tracking control circuit based on the transfer data of each control element tested according to the expression of the transfer function of the tracking control circuit. Here, the embodiment of the present application does not limit the method of testing the transfer function.

[0085] 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 in the tracking control circuit can increase the compensation effect of the position error, thereby improving the control accuracy of the tracking servo control.

[0086] 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.

[0087] 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.

[0088] 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 its own transfer function, the compensator does not need to obtain the transfer function by executing this step 401. For example, if the transfer function of the tracking control circuit of at least one type of data reading and writing device is pre-stored in the compensator, the compensator does not need to execute this step 401, and the transfer function of the tracking control circuit of the data reading and writing device of the target type can be used when calculating the compensation value, wherein 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, and accordingly, in Figure 4 Step 401 is indicated by a dotted box as an optional step.

[0089] 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.

[0090] The optical storage medium is any optical storage medium installed on the data reading and writing device, such as a BD. The multiple positions are multiple guide sectors to be detected on the reference surface of the optical storage medium, that is, ideal irradiation positions of the servo light during the detection process. The multiple position errors of any position are multiple tracking position errors of the servo light irradiated to the any position, wherein the tracking position error is the distance between the spot position of the servo light and the any position in the radial direction.

[0091] The multiple positions are located on at least one guide track to be detected on the reference surface, and the at least one guide track is all guide tracks of the reference surface, and may also be part of the guide tracks of the reference surface. Since the process of detecting the positions on each guide track is similar, here, taking the detection of the positions on part of the guide track as an example, this step 402 is introduced as follows, and in the case of detecting the positions on all guide tracks, the process of detecting the positions on part of the guide track can be referred to.

[0092] Taking the partial guide track where the multiple positions are located as an example, for any layer in the reference surface and the recording layer, the compensator divides the r tracks in any layer into p inner circle tracks and q outer circle tracks. Wherein, p+q=r. The inner circle track refers to the track close to the center of any layer, and the outer circle track refers to the track far from the center of any layer. Exemplarily, the compensator regards the track whose radial distance from the center of any layer is less than or equal to the first distance as the inner circle track, and regards the track whose radial distance from the center of any layer is greater than the first distance as the outer circle track. Optionally, the first distance is the eccentric distance of the optical storage medium during rotation. For example, the value range of the first distance is 0.3nm to 1nm. In the case where the track width is 160nm, when the first distance is 0.3nm, the 1st track to the 500th track in any layer are all inner circle tracks, and when the first distance is 1nm, the 1st track to the 2000th track in any layer are all inner circle 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 embodiments of the present application do not limit the value range and value-taking method of the first distance, that is, there is no limitation on the number of inner circle tracks.

[0093] After determining the p inner circle tracks, the compensator uses the p inner circle tracks of the reference surface as guide tracks to be detected, detects multiple positions on the p inner circle tracks, and obtains multiple position errors of each of the multiple positions.

[0094] 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, and the detection of other position errors at each position can refer to this process.

[0095] In a possible implementation, through the following steps 421 to 424, multiple positions on the p inner ring tracks of the reference surface are detected to obtain a position error of the multiple positions.

[0096] Step 421: The compensator controls the rotating table of the data reading and writing device so that the rotating table drives the optical storage medium to rotate.

[0097] 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.

[0098] 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 to obtain a light sensing signal of the servo light, and the light sensing signal carries information on the position of the servo light spot when scanning the guide track.

[0099] 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.

[0100] Taking the test of multiple positions on p inner circle tracks as an example, in the 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 the p inner circle tracks, wherein the first guide track is any inner circle track currently irradiated by the servo light among the p inner circle tracks, and the second guide track is the inner circle track adjacent to the first guide track among the p inner circle tracks. In the case of adjusting the objective lens in the order from inside to outside, if the first guide track is T among the guide tracks among the p inner circle tracks, (ref，z) , then the second guide track is T among the guide tracks of 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 of the p inner circle tracks (ref，z) , then the second guide track is T among the guide tracks of the p inner tracks (ref，z-1) , where T (ref，z) refers to the zth guide track of the reference surface Ref, z being greater than or equal to 1 and less than or equal to p.

[0101] 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 circle tracks based on the light sensing signal of the servo light.

[0102] As 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, after 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 circle tracks.

[0103] Assuming that each inner track has M guide sectors, the compensator samples the light-sensing signal obtained by rotating p circles to obtain p*M position information of the servo light, each of which corresponds to a guide sector, and each of which is used to indicate the position of the light spot of the servo light irradiated to the corresponding guide sector. Based on the position indicated by each position information of the servo light and the corresponding guide sector, the position error of each guide sector is obtained, wherein the position error of any guide sector is the distance in the radial direction between the position indicated by the position information of the corresponding servo light and the any guide sector, that is, a tracking position error of the servo light.

[0104] Therefore, through the process shown in the above steps 421 to 424, with the guide sector as the position to be detected on the inner circle track, the compensator can obtain a position error of multiple positions on the p inner circle tracks every time the optical storage medium rotates p circles. Assuming that N position errors of each position need to be obtained, the compensator controls the optical storage medium to rotate N*p circles, and every time the optical storage medium rotates p circles, the compensator executes steps 422 to 424, and after the optical storage medium rotates N*p circles, the N position errors of each position in the multiple positions are obtained. Alternatively, the compensator controls the optical storage medium to rotate N*p circles, and during the rotation process, step 422 is continuously executed, and step 423 is executed once after scanning an inner circle track. After the optical storage medium rotates N*p circles, step 424 is executed to obtain N position errors of each position in the multiple positions at one time.

[0105] It should be understood that during the detection process, the servo light scans p inner circle tracks every time the optical storage medium rotates p times. During the scanning process, the servo light spot on the reference surface forms an illumination track of the servo light. Every time the optical storage medium rotates N*p times, the servo light spot on the reference surface can form an illumination track of the servo light on p inner circle tracks. The p inner circle tracks in a spiral form are ideal tracks when the servo light scans p inner circle 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 the guide sector.

[0106] To further reflect the position error between the servo light illumination trajectory and the ideal trajectory, see Figure 7 The illustrative trajectory of a servo light provided in an embodiment of the present application is shown as follows: Figure 7, multiple irradiation tracks of the servo light are shown. The multiple irradiation tracks are different, and multiple position errors obtained by the servo light scanning the same guide sector multiple times are different.

[0107] For another example, Figure 8 The schematic diagram of the local position error of the same inner ring track provided by the embodiment of the present application is shown. Figure 8 Several position error curves are shown (eg Figure 8 Each position error curve is used to indicate the position error of the servo light in the 750th guide sector to the 1100th guide sector of the same inner circle track. Figure 8 It can also be known that the multiple position errors obtained by the servo light scanning the same guide sector multiple times are different. It can be seen that the position error of the servo light in each guide sector has an oscillation characteristic. The compensator can extract a repeatable part from the position error of the same guide sector, and obtain the compensation value of the guide sector based on the repeatable part (such as steps 403-404 described below), so that when reading and writing data in the recording sector corresponding to the guide sector later, the repeatable part can be compensated to the tracking servo control of the servo light to eliminate the repeatable part in the position error and reduce the oscillation amplitude of the position error, thereby reducing the radial offset between the irradiation trajectory of the servo light and the ideal trajectory, thereby improving the control accuracy of the tracking servo control.

[0108] 403. The compensator determines a repeatable runout (RRO) of each position based on the multiple position errors of each position, where the repeatable error refers to a repeatable portion of the position error.

[0109] The repeatable error at any position includes not only the repeatable error but also the non-repeatable runout (NRRO), which refers to the non-repeatable part of the position error. There is one repeatable error at any position and multiple non-repeatable errors at any position.

[0110] The repeatable error of any position is the average value of multiple position errors of any position, and the multiple non-repeatable errors of any position are the differences between the multiple position errors of any position and the repeatable error.

[0111] 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 the M positions is recorded as RRO(.j). The compensator obtains the average value of the 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).

[0112]

[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] Assuming that the j-th position has N non-repeatable errors, the j-th non-repeatable error among the N non-repeatable errors is recorded 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] According to the above method, the compensator can obtain the repeatable error and non-repeatable error of each position on the p inner ring guide rails. In order to further reflect the difference between the repeatable error and the position error at the same position, see Figure 8 The white line in the middle shows a repeatable error curve, which indicates the repeatable error of the servo light in the 750th guide sector to the 1100th guide sector of the inner track. Obviously, 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 for each position and the transfer function.

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

[0119] Exemplarily, the high-frequency part 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 of each position to obtain multiple frequency domain repeatable errors of each position, and 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 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 to obtain 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]

[0125] 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,

[0126] 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:

[0127]

[0128] 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:

[0129]

[0130] The frequency domain interval can include multiple frequencies, and the compensator is based on the frequency domain repeatable error RRO f The formula (j) can be used to calculate the frequency domain repeatability error RRO of the jth position on a certain inner circle track at any frequency f. f (j).

[0131] 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, 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.

[0132] 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.

[0133] 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.

[0134] 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 the position from the time domain to the frequency domain, obtains the time domain repeatable error of the position, and determines the time domain repeatable error as the compensation value of the position.

[0135] In a possible implementation, the compensator uses the product of the high-frequency repeatable error of the position and the target frequency as the frequency domain repeatable error compensation value, wherein the target frequency is greater than or equal to the frequency threshold. The compensator performs an inverse Fourier transform on the frequency domain repeatable error compensation value of the position to convert the frequency domain repeatable error compensation value of the position from the frequency domain to the time domain, obtains the time domain repeatable error compensation value of the position at the target frequency, and uses the time domain repeatable error compensation value as the compensation value of the position.

[0136] 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 an inverse Fourier transform to obtain the time domain repeatable error compensation value a at the jth position at frequency f if .

[0137]

[0138] Among them, f 0 It refers to the reference frequency of the optical storage medium rotation speed, i refers to the reference frequency f 0 Multiples of 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 used, 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.

[0139] 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.

[0140] The high-frequency domain repeatable error is mainly caused by external disturbances. Too high a 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. 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.

[0141] It should be understood that the process shown in the above steps 402-404 is a process of obtaining compensation values ​​of multiple positions based on the transfer function and the detection results of the multiple positions of the optical storage medium.

[0142] 405. The compensator stores the compensation values ​​of the multiple positions.

[0143] 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, based on the identifier of each position in the multiple positions and the compensation of each position, the compensator establishes a mapping relationship between the multiple positions and the compensation values ​​shown in Table 1. 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 a 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. The present embodiment does not limit the values ​​of p and M. As shown in Table 1, the position error compensation of each position using the compensation value is reflected in the compensation of the track width of each position. Therefore, the compensation value of each position is a percentage value of the track width. (ref，1)Taking sector 1 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 (-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).

[0144] Table 1

[0145]

[0146]

[0147] 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.

[0148] After establishing the mapping relationship between the multiple positions and the compensation values, the compensator stores the mapping relationship for subsequent query. By way of example, the compensator stores the mapping relationship in a memory provided by the data reading device or in a memory of an 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.

[0149] Among them, the memory used to store the mapping relationship can be a non-volatile random access memory and / or a volatile memory. Non-volatile memory is, for example, a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM) or a flash memory. Volatile memory is, for example, a random access memory (RAM). By way of example but 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 connection dynamic random access memory (SLDRAM) and direct rambus RAM (DR RAM).

[0150] 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. Figure 4 The dotted box indicates that step 405 is an optional step.

[0151] 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.

[0152] Next, the tracking servo control process based on the compensation values ​​of multiple positions of any optical storage medium is described in detail as follows.

[0153] Fig. 9 It is a flow chart of a servo control method for an optical storage medium provided in an embodiment of the present application, and the method is executed by a compensator in a data reading and writing device.

[0154] 901. A compensator obtains a compensation value corresponding to a position to be read or written in an optical storage medium.

[0155] The optical storage medium is any optical storage medium installed on the data reading and writing device where the compensator is located. The position to be read and written is any recording sector on any recording layer in the optical storage medium, and the compensation value corresponding to the position to be read and written is the compensation value of the guide sector corresponding to the position in the optical storage medium. For the convenience of description, the position to be read and written is called the target recording sector, the recording layer where the target recording sector is located is called the target recording layer, the guide sector corresponding to the target recording sector is called the target guide sector, and the guide track where the target guide sector is located is called the target guide track.

[0156] When reading or writing data in 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, 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, 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.

[0157] The control unit sends the identifier of the target position to the compensator to inform the compensator to irradiate the servo light to the target position, and the compensator compensates for the position error between the irradiation position of the servo light and the target position. After obtaining the identifier of the target position, the compensator queries the compensation value of the target position from the corresponding relationship between the multiple positions of the optical storage medium and the compensation value (as shown in Table 1), and the compensation value of the target position is the compensation value corresponding to the position to be read or written.

[0158] In some embodiments, if the compensation value of the target position cannot be found, at least one position of the reference surface in the optical storage medium is detected to obtain the compensation value of the at least one position, wherein the at least one position includes the target position, and the compensation value of the target position can be obtained at this time. The process of detecting at least one position of the reference surface in the optical storage medium to obtain the compensation value of the at least one position can refer to the process shown in the above steps 402 to 404, and will not be repeated here.

[0159] 902. The compensator compensates for the position error of the servo light of the data reading and writing device based on the compensation value.

[0160] 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.

[0161] 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.

[0162] The objective lens is the objective lens shared by the read-write light and the servo light.

[0163] 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 and written is less than or equal to the compensation value of the target position.

[0164] The above description is based on the example of the compensator controlling the objective lens based on the compensation value of the target position. In other embodiments, the compensator controls the tracking servo controller C in the tracking servo control circuit based on the compensation value of the target position to control the objective lens. Figure 5 For example, the addition and subtraction unit G in the tracking control circuit subtracts the detected position of the servo light from the target position to obtain the position error of the servo light, and the compensator sends the compensation value of the target position to the addition and subtraction unit G, which adds the compensation value to the position error to obtain the compensated position error, and sends the compensated position error to the tracking servo controller C. The track servo controller C generates a tracking servo signal based on the compensated position error, and sends the tracking servo signal to the torquer P, which controls the objective lens based on the tracking servo signal.

[0165] The above is explained using 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 the above-mentioned manner of controlling the objective lens.

[0166] In some embodiments, during the process of reading and writing data, the compensator also determines whether the written data in the target recording layer currently being read and written is overwritten. If the written data is overwritten, multiple positions in the optical storage medium are detected again to update the compensation values ​​of the multiple positions. For example, after writing the first number of recording tracks in the target recording layer, the first number of data tracks are obtained, and the detector detects the intersection of the first number of data tracks. If any data track in the first number of data tracks intersects with the adjacent data track, the data of the any data track at the intersection covers the data of the adjacent data track. In this case, multiple positions in the optical storage medium are detected again to obtain new compensation values ​​for the multiple positions, and the existing compensation values ​​of the multiple positions are updated to new compensation values. According to the compensation values ​​corresponding to each position on the recording track corresponding to the any data track, data is re-written to the recording track to obtain a new data track to avoid the new data track from intersecting with the adjacent data track. Among them, the first number is greater than or equal to 1 and less than the total number of recording tracks in the recording layer. Here, the embodiment of the present application does not limit the first number.

[0167] The compensator detects the intersection of the data tracks of the first number, including: detecting the bit error rate of the data tracks of the first number, if the bit error rate of any data track is greater than or equal to the bit error rate threshold, then 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, then the data track does not intersect with the adjacent data track. The bit error rate refers to the original bit error rate parsed by the data reading and writing device when reading data from the optical storage medium. The bit error rate threshold can be set according to the specific implementation scenario, and the bit error rate threshold is not limited here.

[0168] 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.

[0169] 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 process of tracking servo control of the servo light, which can further improve the control accuracy of the tracking servo control.

[0170] According to the method provided by the embodiment of the present application, since the position to be read and written in the optical storage medium corresponds to a guide sector on the reference surface of the optical storage medium, the current position error of the servo light is compensated by the compensation value corresponding to the position to be read and written for the position error between the irradiation position of the servo light on the reference surface and the guide sector, so as to reduce 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. 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 and the position to be read and written is also reduced, so that the read-write light acts on the position to be read and written as much as possible. If data is written at the position to be read and written, the width of the track where the position to be read and written is located can be reduced to avoid writing to adjacent tracks, thereby avoiding the track where the position to be read and written is located from intersecting with adjacent tracks. If data is read at the position to be read and written, the data recorded at the position can be read as much as possible to ensure the correctness of the read data.

[0171] Fig. 9 The embodiment shown is described 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 be based on Fig. 9 The process shown in the figure is to perform tracking servo control on the servo light, that is, it can be used when reading and writing data on all tracks of the recording layer of the optical storage medium. Fig. 9 The process shown performs tracking servo control on the servo light.

[0172] In other embodiments, the compensator can only read and write data to a portion of the track in the recording layer. Fig. 9 The process shown in the figure is to perform tracking servo control on the servo light, and reading and writing data to other tracks of the recording layer is not adopted. Fig. 9The process shown is used to perform tracking servo control. That is, only when the position to be read or written is located in a designated part of the track in the optical storage medium, tracking servo control is performed based on the compensation value corresponding to the position.

[0173] Take the part of the track that is close to the center of the optical storage medium (i.e., the inner circle track) as an example. Fig.10 A control logic diagram of a tracking servo control provided by an embodiment of the present application is shown as follows: Fig.10 As shown, 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 at the inner track of the reference surface. If it is located at 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 at the position of the inner track as much as possible. According to this method, when reading and writing data on the inner track, due to the reduction of the 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 on the inner track of the recording layer and the position to be read and written is also reduced, so that the read-write light acts on the position to be read and written as much as possible. If data is written at the position to be read and written, the track width at the position to be read and written in the data track can be reduced to avoid writing to the adjacent data track. If data is read at the position to be read and written, the data recorded at the position can be read as much as possible to ensure the correctness of the read data.

[0174] like Fig.10 As shown, if the target position is not located on the inner circle track of the reference surface, but on the outer circle 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 circle track, the intersection of the data tracks of the recording layer can be avoided. If the tracking control circuit uses the inner circle track of the recording layer when performing tracking servo control on the servo light irradiated on the outer circle track, the servo control accuracy of the outer circle 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 circle track of the recording layer, the tracking control circuit using the ATS-based position control method may use the inner circle track of the recording layer that has been written.

[0175] 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:

[0176] For example, Fig.11is a schematic diagram of a data writing process of an optical storage medium provided in an embodiment of the present application, such as Fig.11 As shown, during the process of starting the system, when it is detected that the optical storage medium is placed into 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 tracking servo control circuit, 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.

[0177] The control unit starts the tracking servo control: controls the first laser emitter to emit a reading light to the optical storage medium, controls the second laser emitter to emit a 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 a 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 irradiates 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 circle 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.

[0178] 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 to the recording layer L1, the intensity of the read-write light is adjusted so that the read-write light changes from the reading light to the writing light, the tracking servo control of the servo light is turned on, and data is written to each track of the recording layer L1 in sequence from the inside to the outside of the track, and 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 the write command to the recording layer L2 is read, 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 accordance with the writing method 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.

[0179] exist Fig.11In the embodiment shown, the data reading and writing device writes data to each recording layer of the optical storage medium in sequence according to the order of the recording layers. In other embodiments, the data reading and writing device may also write data to the recording layer not in the order of the recording layers, but according to the write command, write data to the recording layer specified by the write command. Fig.12 In the embodiment shown, when writing each recording layer, the data reading and writing device writes data on the track of the recording layer in sequence from the inside to the outside. In other embodiments, the data reading and writing device does not write data on the track of the recording layer in sequence from the inside to the outside, but writes data to the track specified by the write command or the position of the specified track according to the write command.

[0180] 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 effect of the present application on the tracking servo control of the servo light based on the compensated position error, see Fig.12 A comparison diagram of the position error of a servo light provided by an embodiment of the present application is shown. The amplitude-frequency curve composed of "*" is used to reflect the change in the frequency domain of the amplitude of the position error of the servo light after 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 frequency domain of the amplitude of the position error of the servo light after 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%.

[0181] In an exemplary embodiment, a servo control device for an optical storage medium is also provided, and the servo control device can be configured as the compensator in the above embodiments, and is used to execute the method executed by the compensator. Fig.13 A schematic diagram of a servo control device for an optical storage medium provided by an embodiment of the present application is shown in FIG. Fig.13 The service control device 1300 shown includes:

[0182] An acquisition module 1301 is used to acquire a compensation value corresponding to a position to be read or written in the optical storage medium;

[0183] A compensation module 1302, used to compensate for the position error of the servo light of the data reading and writing device based on the compensation value;

[0184] 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.

[0185] In a possible implementation, the position to be read or written is located on a track close to the center of the optical storage medium.

[0186] In a possible implementation, the position to be read or written is located in a partial track in the optical storage medium.

[0187] In a possible implementation, the servo control device 1300 further includes:

[0188] The detection module is used to detect multiple positions of the optical storage medium to obtain compensation values ​​of the multiple positions.

[0189] In a possible implementation, the detection module includes:

[0190] A detection submodule, used to detect multiple positions of the optical storage medium to obtain multiple position errors of each position in the multiple positions;

[0191] A first determination submodule is used 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 part of the position error;

[0192] The second determination submodule is used to determine the compensation value of each position based on the repeatable error of each position.

[0193] In a possible implementation manner, the second determining submodule is used to:

[0194] Perform frequency domain transformation on the repeatable error of each position to obtain multiple frequency domain repeatable errors of each position, where the multiple frequency domain repeatable errors correspond to different frequencies;

[0195] 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, 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.

[0196] In a possible implementation, the servo control device 1300 further includes:

[0197] An acquisition module 1301 is used to acquire a transfer function of a tracking control circuit of a servo light in a data reading and writing device;

[0198] The detection module is further used to obtain compensation values ​​of multiple positions based on the transfer function and the detection results of detecting multiple positions of the optical storage medium.

[0199] In a possible implementation, the detection module is further used to:

[0200] The detection module is also used to detect multiple positions in the optical storage medium again to update compensation values ​​of the multiple positions if the written data is overwritten during the data reading and writing process.

[0201] Based on the above various implementations, further combinations can be made to provide more implementations.

[0202] 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 the method embodiment to realize the specific details. Please refer to the above-mentioned method embodiment, and for the sake of brevity, they will not be repeated here.

[0203] It should be understood that when the servo control device 1300 compensates for the position error of the servo light, the division of the above-mentioned functional modules is only used as an example for illustration. In practical applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the servo control device 1300 is divided into different functional modules to complete all or part of the functions described above. In addition, the servo control device 1300 provided in the above embodiment and the above method embodiment belong to the same concept, and the specific implementation process thereof is detailed in the above method embodiment, which will not be repeated here.

[0204] In an exemplary embodiment, the compensator or servo control device 1300 mentioned above can be implemented by a processor, and the processor 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 medium 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 may be implemented in at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), and programmable logic array (PLA).

[0205] The present application also provides a compensator used in a data reading and writing device, the data reading and writing device 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, the processor is used to execute program code, so that the compensator executes to complete the servo control method for optical storage medium in the above embodiment. For example Fig.14The schematic diagram of the structure of a compensator provided by an embodiment of the present application is shown, and 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 optical storage medium in the above-mentioned embodiment. The compensator 1400 can be a chip, a component or a module.

[0206] In an exemplary embodiment, a computer-readable storage medium is also provided, such as a memory including at least one program code, and the at least one program code can be executed by a processor in a data reading and writing device to complete the servo control method for optical storage media in the above embodiment. Exemplarily, the processor can be configured as the compensator involved above. Computer-readable storage medium For example, the computer-readable storage medium is a non-temporary 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.

[0207] The embodiment of the present application also provides a computer program product or a computer program, which includes at least one program code, which is stored in a computer-readable storage medium, and a processor of a data reading and writing device reads and executes the at least one program code from the computer-readable storage medium, so that the data reading and writing device implements the servo control method for optical storage medium in the above embodiment. Exemplarily, the processor can be configured as the compensator involved above.

[0208] Among them, the device, equipment, computer-readable storage medium, computer program product or chip provided in this embodiment is used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be repeated here.

[0209] In the several embodiments provided in the present 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 only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, 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.

[0210] The units described as separate components may or may not be physically separated, 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 different places. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0211] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0212] 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, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to perform 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 USB flash drives, mobile hard drives, ROM, RAM, magnetic disks or optical disks.

[0213] 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 may 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 "plurality" means two or more. The words "first", "second", etc. do not limit the quantity and execution order, and the words "first", "second", etc. do not limit them to be different.

[0214] In this application, the words "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the words "exemplary" or "for example" is intended to present the related concepts in a concrete way.

[0215] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope 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 corresponding to a position to be read or written in the optical storage medium; Based on the compensation value, compensating for a position error of a servo light of a data reading and writing device; 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 position to be read or written is located on a track close to the center of the optical storage medium.

3. The method according to claim 1, characterized in that The positions to be read and written are located in a part of the track in the optical storage medium.

4. The method according to any one of claims 1 to 3, 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.

5. The method according to claim 4, 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.

6. The method according to claim 5, characterized in that Determining the compensation value of each position based on the repeatable error of each position includes: Performing frequency domain transformation on the repeatable error at each position to obtain multiple frequency domain repeatable errors at each position, wherein the multiple frequency domain repeatable errors correspond to different frequencies; Based on a high-frequency repeatable error among a plurality of frequency-domain repeatable errors at each position, a compensation value at each position 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.

7. The method according to any one of claims 4 to 6, 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.

8. The method according to any one of claims 4 to 7, 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.

9. A servo control device for an optical storage medium, characterized in that: The device comprises: An acquisition module, used for acquiring a compensation value corresponding to a position to be read or written in the optical storage medium; A compensation module, used for compensating for a position error of a servo light of a data reading and writing device 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.

10. The device according to claim 9, characterized in that The position to be read or written is located on a track close to the center of the optical storage medium.

11. The device according to claim 9, characterized in that The positions to be read and written are located in a part of the track in the optical storage medium.

12. The device according to any one of claims 9 to 11, 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.

13. The device according to claim 12, 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.

14. The device according to claim 13, characterized in that The second determining submodule is used for: Performing frequency domain transformation on the repeatable error at each position to obtain multiple frequency domain repeatable errors at each position, wherein the multiple frequency domain repeatable errors correspond to different frequencies; Based on a high-frequency repeatable error among a plurality of frequency-domain repeatable errors at each position, a compensation value at each position 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.

15. The device according to any one of claims 12 to 14, 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.

16. The device according to any one of claims 12 to 15, 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.

17. 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 8.

18. 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. The processor is used to execute program code so that the compensator executes the method as described in any one of claims 1 to 8.

19. A computer-readable storage medium, characterized in that: At least one program code is stored in the storage medium, and the at least one program code is read by a processor in the data reading and writing device to enable the data reading and writing device to execute the method as claimed in any one of claims 1 to 8.

20. A computer program product, characterized in that The computer program product 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 according to any one of claims 1 to 8.

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