Servo control method and device for fluorescent optical discs, and data reading and writing device

Abstract

This application discloses a servo control method and apparatus for a fluorescent optical disc, as well as a data reading and writing device, belonging to the field of optical disc technology. The method includes: a servo control unit controlling servo light to focus on the servo surface of the fluorescent optical disc; a light receiver obtaining multiple first servo error signals based on servo feedback light, and providing these signals to a first signal processing unit, wherein the first servo error signals indicate the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc; the first signal processing unit obtaining a second servo error signal based on the multiple first servo error signals, and providing this second servo error signal to the servo control unit, wherein the second servo error signal indicates the change in the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc over time; and the servo control unit obtaining an adjusted servo control signal based on the second servo error signal. This application improves the accuracy of servo control.

Description

Technical Field

[0001] This application relates to the field of optical disc technology, and in particular to a servo control method and apparatus for fluorescent optical discs, and a data reading and writing device. Background Technology

[0002] Optical storage media are widely used for storing cold data due to their ability to preserve data for extended periods; examples include fluorescent optical discs (fluorescent optical discs). The process of reading and writing data from a fluorescent optical disc involves continuously focusing a laser beam onto the disc and adjusting the focus position based on the focusing result. This dynamic process requires multiple adjustments to the objective lens; each adjustment until the next is called an adjustment process. Each adjustment process includes: a servo control unit controlling the objective lens to focus servo light onto the fluorescent optical disc based on a servo control signal; a photodetector receiving the light signal from the fluorescent optical disc, converting it into a servo error signal, and providing this error signal to the servo control unit; and the servo control unit obtaining a servo control signal based on this error signal, which is then used to adjust the objective lens in the next adjustment process, ensuring that the objective lens focuses the servo light onto the fluorescent optical disc.

[0003] Currently, when processing signals generated during the servo control process of fluorescent optical discs, the traditional signal processing methods used for general optical discs are typically employed, such as treating the signals generated during the servo control process as continuous signals.

[0004] However, since fluorescent optical discs contain discrete signals stored in the form of holes, the servo feedback light triggered by the laser on the fluorescent optical disc exhibits discrete characteristics, and traditional signal processing methods cannot meet the accuracy requirements of servo control. Summary of the Invention

[0005] This application provides a servo control method and apparatus for fluorescent optical discs, as well as a data reading and writing device. This application effectively improves the accuracy of servo control based on servo feedback light from fluorescent optical discs. The technical solution provided by this application is as follows:

[0006] In a first aspect, this application provides a servo control method for a fluorescent optical disc. This method is applied to a servo control device for a fluorescent optical disc. The servo control device for a fluorescent optical disc includes: a servo control unit, an optical processing unit, a light receiver, and a first signal processing unit. The method includes: the servo control unit controlling the optical processing unit based on a servo control signal, such that servo light is focused onto the servo surface of the fluorescent optical disc by the optical processing unit; the light receiver receiving servo feedback light from the fluorescent optical disc to the servo light, obtaining multiple first servo error signals based on the servo feedback light, and providing multiple first servo error signals to the first signal processing unit, wherein the first servo error signals indicate the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc; the first signal processing unit obtaining a second servo error signal based on the multiple first servo error signals, and providing the second servo error signal to the servo control unit, wherein the second servo error signal indicates the change in the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc over time; and the servo control unit obtaining an adjusted servo control signal based on the second servo error signal.

[0007] The first servo error signal indicates the distance between the servo light spot position on the fluorescent optical disc and the target position. This first servo error signal is discrete. The second servo error signal indicates how the distance between the servo light spot position on the fluorescent optical disc and the target position changes over time. This second servo error signal is continuous. The first signal processing unit processes the first servo error signal, converting it into a continuous second servo error signal. Thus, during servo control, considering the discrete nature of the servo feedback light from the fluorescent optical disc, the processing by the optical receiver and the first signal processing unit converts the discrete servo feedback light into a continuous second servo error signal. This eliminates the need for continuous servo light feedback signals during servo control, effectively improving the accuracy of servo control based on the fluorescent optical disc's feedback light and contributing to improved read / write characteristics of the fluorescent optical disc.

[0008] In one implementation, the first signal processing unit obtains a second servo error signal based on multiple first servo error signals, including: the first signal processing unit acquiring the timing sequence of the multiple first servo error signals; the first signal processing unit predicting the change trend of the voltage value between the generation times of any two time-adjacent first servo error signals based on the voltage values ​​of any two time-adjacent first servo error signals; and the first signal processing unit obtaining the second servo error signal based on the change trend and the multiple first servo error signals.

[0009] Optionally, the servo control device for the fluorescent optical disc further includes a second signal processing unit. In this case, the method further includes: the second signal processing unit receiving a plurality of first servo error signals provided by the optical receiver; the second signal processing unit dividing the plurality of first servo error signals into a plurality of signal sets; and the second signal processing unit providing the plurality of signal sets to the first signal processing unit.

[0010] In one implementation, the second signal processing unit divides multiple first servo error signals into multiple signal sets, including: the second signal processing unit divides the multiple first servo error signals into multiple signal sets based on the distribution of their voltage values. For example, the second signal processing unit can determine the proximity of the voltage values ​​of the multiple first servo error signals based on the distribution of their voltage values, and based on this proximity, group the multiple first servo error signals with relatively close voltage values ​​into the same signal set, and group the multiple first servo error signals with significantly different voltage values ​​into different signal sets. When the voltage values ​​of the multiple first servo error signals are relatively close, it indicates that the content represented by the multiple first servo error signals has a high degree of commonality, so the multiple first servo error signals can be grouped into the same signal set. When the voltage values ​​of the multiple first servo error signals differ significantly, it indicates that the content represented by the multiple first servo error signals differs significantly, so the multiple first servo error signals can be grouped into different signal sets.

[0011] Optionally, the servo control device for the fluorescent optical disc further includes a third signal processing unit. In this case, the method further includes: the third signal processing unit receiving multiple signal sets provided by the second signal processing unit; the third signal processing unit obtaining a voltage threshold for any signal set based on the voltage value of a first servo error signal in any signal set; the third signal processing unit adjusting the voltage of the first servo error signal in any signal set based on the voltage threshold to obtain adjusted multiple signal sets; and the third signal processing unit providing the adjusted multiple signal sets to the first signal processing unit.

[0012] Processing the first servo error signal by the second signal processing unit and the third signal processing unit can improve the accuracy of the first servo error signal, which helps to improve the precision of servo control based on the first servo error signal.

[0013] In one implementation, the third signal processing unit obtains the voltage threshold of any signal set based on the voltage value of the first servo error signal in any signal set, including: the third signal processing unit obtains the voltage coverage range of the first servo error signal in any signal set based on the voltage value of the first servo error signal in any signal set; and the third signal processing unit determines the voltage threshold of any signal set based on the voltage coverage range of any signal set.

[0014] For example, given a signal set where multiple first servo error signals are relatively close and likely represent the same content, after obtaining the voltage threshold of the signal set, the voltage values ​​of all first servo error signals in the set can be adjusted to equal the voltage threshold, allowing the adjusted first servo error signals to represent the same content. In other words, the voltage of the adjusted first servo error signal is equal to the voltage threshold of the signal set to which the first servo error signal belongs.

[0015] Secondly, this application provides a servo control device for a fluorescent optical disc. The device includes a servo control unit, an optical processing unit, a light receiver, and a first signal processing unit. The servo control unit controls the optical processing unit based on a servo control signal, such that servo light is focused onto the servo surface of the fluorescent optical disc by the optical processing unit. The light receiver receives servo feedback light from the fluorescent optical disc, obtains multiple first servo error signals based on the servo feedback light, and provides these multiple first servo error signals to the first signal processing unit. The first servo error signals indicate the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc. The first signal processing unit obtains a second servo error signal based on the multiple first servo error signals and provides this second servo error signal to the servo control unit. The second servo error signal indicates how the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc changes over time. The servo control unit also obtains an adjusted servo control signal based on the second servo error signal.

[0016] Optionally, the first signal processing unit is specifically configured to: acquire the timing of multiple first servo error signals; predict the change trend of the voltage value between the generation times of any two time-adjacent first servo error signals based on the voltage values ​​of any two time-adjacent first servo error signals; and obtain a second servo error signal based on the change trend and the multiple first servo error signals.

[0017] Optionally, the device further includes a second signal processing unit. The second signal processing unit is configured to: receive a plurality of first servo error signals provided by the optical receiver; divide the plurality of first servo error signals into a plurality of signal sets; and provide the plurality of signal sets to the first signal processing unit.

[0018] Optionally, the second signal processing unit is specifically used to: divide the multiple first servo error signals into multiple signal sets based on the distribution of voltage values ​​of the multiple first servo error signals.

[0019] Optionally, the device further includes a third signal processing unit. The third signal processing unit is configured to: receive multiple signal sets provided by the second signal processing unit; obtain a voltage threshold for any signal set based on the voltage value of a first servo error signal in any signal set; adjust the voltage of the first servo error signal in any signal set based on the voltage threshold to obtain adjusted multiple signal sets; and provide the adjusted multiple signal sets to the first signal processing unit.

[0020] Optionally, the third signal processing unit is specifically used to: obtain the voltage coverage range of the first servo error signal in any signal set based on the voltage value of the first servo error signal in any signal set; and determine the voltage threshold of any signal set based on the voltage coverage range of any signal set.

[0021] Optionally, the voltage of the adjusted first servo error signal is equal to the voltage threshold of the signal set to which the first servo error signal belongs.

[0022] Optionally, the light receiving unit is a photomultiplier tube.

[0023] Thirdly, this application provides a data reading and writing device for a fluorescent optical disc, which includes the servo control device provided in the first aspect of this application and any possible implementation thereof. For example, the data reading and writing device includes a processor for executing program code, causing the data reading and writing device to perform the methods provided in the first aspect of this application and any possible implementation thereof.

[0024] Fourthly, this application provides a computer program product containing instructions that, when executed by a data reading and writing device, cause the data reading and writing device to perform the methods provided in the first aspect of this application and any possible implementation thereof.

[0025] Fifthly, this application provides a computer-readable storage medium that is a non-volatile computer-readable storage medium, which includes computer program instructions. When the computer program instructions are executed by a data reading and writing device, the data reading and writing device performs the method provided in the first aspect of this application and any of its possible implementations. Attached Figure Description

[0026] Figure 1 This is a cross-sectional schematic diagram of a fluorescent optical disc provided in an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of the track arrangement of a fluorescent optical disc provided in an embodiment of this application;

[0028] Figure 3 This is a partial schematic diagram of the guide layer of a fluorescent optical disc provided in an embodiment of this application;

[0029] Figure 4 This is a schematic diagram of a servo control device for a fluorescent optical disc provided in an embodiment of this application;

[0030] Figure 5 This is a schematic diagram of another servo control device for a fluorescent optical disc provided in an embodiment of this application;

[0031] Figure 6 This is a schematic diagram of the structure of an optical processing unit provided in an embodiment of this application;

[0032] Figure 7 This is a flowchart of a servo control method for a fluorescent optical disc provided in an embodiment of this application;

[0033] Figure 8 This is a schematic diagram of a plurality of first servo error signals provided in an embodiment of this application;

[0034] Figure 9 This is a schematic diagram of multiple first servo error signals after removing noise points, provided in an embodiment of this application;

[0035] Figure 10 This is a schematic diagram of a first servo error signal that is not adjusted according to a voltage threshold, provided in an embodiment of this application;

[0036] Figure 11 This is a schematic diagram of a first servo error signal adjusted according to a voltage threshold provided in an embodiment of this application;

[0037] Figure 12 This is a schematic diagram of the structure of an LSTM neural network provided in an embodiment of this application;

[0038] Figure 13 This is a schematic diagram of the structure of a lead-lag controller provided in an embodiment of this application;

[0039] Figure 14 This is a schematic diagram of another lead-lag controller provided in an embodiment of this application;

[0040] Figure 15 This is a schematic diagram of the structure of a fuzzy adaptive PID controller provided in an embodiment of this application;

[0041] Figure 16 This is a schematic diagram of the structure of a data read / write device provided in an embodiment of this application. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0043] This application relates to a servo control device for a fluorescent optical disc. The servo control device is used to read and / or write data (i.e., read and write data) on the fluorescent optical disc. The fluorescent optical disc is mounted on the servo control device. A fluorescent optical disc is a recording medium that records and reads data by laser irradiation. Although a fluorescent optical disc is used as an example in this application, this application is also applicable to other optical storage media with similar data reading and writing methods to fluorescent optical discs, and these are not listed here.

[0044] For example, Figure 1 This is a cross-sectional schematic diagram of a fluorescent optical disc provided in an embodiment of this application. For example... Figure 1 As shown, the phosphor optical disc 100 includes a protective layer 11, s information layers 12, a reflective layer 13, and a guiding layer 14 arranged sequentially. Here, s is an integer greater than or equal to 1; however, the value of s is not limited in this embodiment. The functions of each layer in the phosphor optical disc 100 are as follows:

[0045] The protective layer 11 is used to protect each information layer 12, so that the fluorescent optical disc 100 can withstand frequent use, fingerprints, scratches and dirt, etc., and ensure the security of the data stored in the fluorescent optical disc 100.

[0046] In the case of multiple information layers 12, in order to distinguish each information layer 12, each information layer 12 is numbered L1 to Ls according to its distance from the bootstrap layer 14. Among them, L1 is the information layer 12 closest to the bootstrap layer 14, and Ls is the information layer 12 farthest from the bootstrap layer 14.

[0047] Information layer 12 is used to record data. The data recording method is as follows: when a laser irradiates information layer 12, it causes physical or chemical changes in the medium constituting the surface of information layer 12, altering the state of the medium. The recorded data is represented by the state of this medium. Taking a phase change material as an example, when a laser irradiates information layer 12, the laser causes a portion of the phase change material to change from an amorphous state to a crystalline state. The crystalline phase change material can represent one type of data, such as data "1". Regions in information layer 12 where no phase change material is distributed can represent another type of data, such as data "0". Of course, the crystalline phase change material can also represent data "0", and regions in information layer 12 where no phase change material is distributed can represent data "1". Alternatively, when a laser irradiates information layer 12, the laser can cause a portion of the phase change material to change from an amorphous state to a crystalline state. Depending on the data being written, the crystalline state can exhibit multiple excited states, with different excited states representing different written data. For example, when different data is written, the area of ​​the part of the phase change material that is converted into the crystalline state is different, and different sizes represent different written values.

[0048] For example, information layer 12 includes a land-in area and a data area. The land-in area stores metadata of the fluorescent optical disc, including relevant parameters of each layer of the fluorescent optical disc 100. The data area is used to record data and includes tracks. Figure 2 As shown, the tracks are arranged in an Archimedean spiral pattern on the information layer 12 from the inside out. The servo control device of the fluorescent optical disc can record data (i.e., write data) along the tracks on the information layer 12 by irradiating the tracks with laser light, so that the data is arranged in the form of tracks on the information layer 12.

[0049] A reflective layer 13 is disposed between the guide layer 14 and the information layer L1. The reflective layer 13 functions to reflect read / write light and transmit servo light. When read / write light shines on the reflective layer 13, the reflective layer 13 reflects the light to prevent it from shining on the guide layer 14. When servo light shines on the reflective layer 13, the reflective layer 13 transmits the light, allowing it to shine on the guide track 141 of the guide layer 14, thus guiding the read / write light to read and write data on the information layer 12. In this way, the reflective layer 13 enables servo light to penetrate through S information layers 12 to shine on the guide layer 14, while preventing read / write light from shining on the guide layer 14.

[0050] Figure 3 This is a partial schematic diagram of a guide layer 14 provided in an embodiment of this application. Figure 3 As shown, the guide layer 14 includes grooves (also called pits) and blank areas (also called lands) in adjacent grooves. The pits and lands alternate, forming a track arranged in an Archimedean spiral pattern from the inside out. A schematic diagram of this track is provided below. Figure 1 This track is called guide track 141 or guide slot. Guide track 141 is a position guide used to record the read / write position. The arrangement of guide track 141 is the same as the arrangement of tracks in information layer 12. Because the arrangement of guide track 141 is the same as the arrangement of tracks in information layer 11, such as Figure 1As shown, two laser beams are respectively irradiated onto the storage medium through objective lenses. One laser beam irradiates the guide track 141 to guide the other laser to read and write data on the track corresponding to information layer L1. To distinguish between the two types of lasers, the laser guiding the reading and writing is called the servo light, and the laser used for reading and writing data is called the read / write light. Furthermore, in this embodiment, the positions of the objective lenses focusing the servo light and the read / write light are fixed. When the fluorescent optical disc 100 has multiple information layers 12, during the reading and writing of data on information layer L1, the servo light irradiates the guide layer 14. During the reading and writing of data on information layers Li from information layers L2 to Ls, the servo light irradiates information layer Li-1. That is, information layer Li-1 is used as the guide layer when reading and writing data on information layer Li. Thus, it can be seen that information layers L1 to Ls-1 and the guide layer 14 can all play a guiding role. The guiding function of information layers L1 to Ls-1 and the guiding layer 14 mainly relies on servo light irradiating the surface of the guiding layer. Therefore, this surface is also called the reference surface (Ref) or the servo surface. For ease of description, the surfaces of the information layers multiplexed as guiding layers and the surface of the guiding layer 14 will be collectively referred to as the servo surface.

[0051] Next, combined Figure 4 The principle of the servo control device for reading and writing data on a fluorescent optical disc is described below:

[0052] Figure 4 This is a schematic diagram of a servo control device for a fluorescent optical disc provided in an embodiment of this application. Figure 4As shown, the servo control device 200 for the phosphor optical disc includes a servo control unit 21, an optical processing unit (OPU) 22, a rotary stage 23, and a signal processing unit 24. The rotary stage 23 is used to mount the phosphor optical disc 100. The rotary stage 23 rotates under the control of the servo control unit 21, causing the phosphor optical disc 100 to rotate with the rotary stage 23. The servo control unit 21 is also used to control the optical processing unit 22, for example, adjusting the position of the objective lens so that the objective lens focuses the laser onto the phosphor optical disc 100. After the laser shines on the phosphor optical disc 100, the phosphor optical disc 100 emits servo feedback light in response to the servo light. The signal processing unit 24 is used to receive the servo feedback light from the phosphor optical disc 100, convert the servo feedback light into a servo error signal, and provide the servo error signal to the servo control unit 21. The servo control unit 21 is also used to adjust the servo control signal controlling the optical processing unit 22 based on the servo error signal, and adjust the position of the objective lens through the servo control signal so that the objective lens focuses the laser more accurately onto the phosphor optical disc 100. When the servo light is focused on the servo surface, the read / write light can be focused on the information layer Lh under the guidance of the servo light. The information layer Lh will emit read / write feedback light in response to the read / write light, and data read / write can be performed on the information layer Lh based on this read / write feedback light. Here, the information layer Lh is the h-th information layer 12 in the fluorescent optical disc 100, and h is greater than or equal to 1 and less than or equal to s.

[0053] In one implementation, such as Figure 5 As shown, the signal processing unit 24 may include an optical receiver 241 and a first signal processing unit 242. Optionally, as... Figure 5 As shown, the signal processing unit 24 may further include a second signal processing unit 243 and a third signal processing unit 244. For example, the light receiver may be a photomultiplier tube (PMT). When the light receiver is a photomultiplier tube, since the photomultiplier tube can obtain an electrical signal reflecting the light intensity based on the light intensity of the light signal, and can obtain a servo error signal based on the unipolar light signal, the cost of the photomultiplier tube is lower, thus reducing the cost of the servo control device for the fluorescent optical disc.

[0054] Figure 6 This is a schematic diagram of the structure of an optical processing unit provided in an embodiment of this application. For example... Figure 6As shown, the optical processing unit 22 is equipped with a read / write optical path and a servo optical path. The read / write optical path is used to emit read / write light and transmit read / write feedback light to the fluorescent optical disc 100. The read / write light includes read light and write light, both of which are laser beams illuminating the fluorescent optical disc 100. The write light is used to write data to the fluorescent optical disc 100. The read light is used to read data from the fluorescent optical disc 100. The read / write feedback light is the feedback light from the fluorescent optical disc 100 to the read / write light. The read / write feedback light includes read feedback light and write feedback light. The read feedback light is the feedback light from the fluorescent optical disc 100 to the read light; processing the read feedback light enables the reading process. The write feedback light is the feedback light from the fluorescent optical disc 100 to the write light. When the fluorescent optical disc 100 uses a laser to change the medium on the surface of the information layer 12 to write data, the write feedback light is the fluorescence generated by the write light exciting the medium on the surface of the information layer 12. Similarly, the read feedback light is the fluorescence generated by the read light exciting the medium on the surface of the information layer 12. The servo optical path is used to emit servo light to the phosphor optical disc 100 and transmit servo feedback light. The servo feedback light is the feedback light from the phosphor optical disc 100 to the servo light, and the servo control device of the phosphor optical disc realizes the servo control process by processing the servo feedback light. In this embodiment, when the information layer Li-1 is multiplexed as a guide layer for reading and writing data on the information layer Li-1, the servo feedback light is the fluorescence generated by the medium on the surface of the information layer Li-1 excited by the servo light. Unlike the information layer 12, the guide layer 14 relies on the guide track 141 formed by pits and lands to achieve the guiding function. In this case, the servo feedback light is the fluorescence reflected by the pits and lands in the guide layer 14 to the servo light.

[0055] The optical transmission process of read / write light and servo light on their respective optical paths is described below.

[0056] The servo control unit 21 controls the laser emitter a1 to emit laser light towards the collimator a2. The collimator a2 converts the diverging laser light into parallel light and provides this parallel light to the shaping prism a3. The shaping prism a3 converts the parallel light, which appears as an elliptical spot, into a circular spot and provides this circular spot parallel light to the spectroscope a4. The spectroscope a4 splits the circular spot parallel light into read / write light and servo light, providing read / write light to the polarizing spectroscope a51 on the read / write light path and servo light to the polarizing spectroscope a52 on the servo light path.

[0057] A polarizing beam splitter a51 transmits incident read light to an objective lens (OB) a61 on the read / write optical path. Based on servo control of a servo control unit, the objective lens a61 focuses the read light onto the information layer 12 of the fluorescent optical disc 100, forming a read / write light spot on the information layer 12. The information layer 12 is excited by the read / write light to generate read / write feedback light. The read / write feedback light is reflected back to the objective lens a61 and then transmitted through the objective lens a61 to the polarizing beam splitter a51. The polarizing beam splitter a51 reflects the read / write feedback light towards the light receiver a71. The light receiver a71 detects the read / write feedback light and obtains a photosensitive signal of the read / write light. This photosensitive signal carries the position information of the read / write light spot to indicate the illumination position of the read / write light on the information layer 12. To facilitate the distinction between the read / write light and the read / write feedback light, Figure 6 The read / write light and read / write feedback light are shown separately in the illustration, but this is not intended to limit the positions of the read / write light and the read / write feedback light. The positions of the read / write light and the read / write feedback light may overlap or may not overlap. This application does not specifically limit them.

[0058] Polarizing beam splitter a52 transmits incident servo light to objective lens a62 on the servo optical path. Objective lens a62, based on servo control of the servo control unit, focuses the servo light onto the servo surface of phosphor optical disc 100, forming a servo light spot on the servo surface. The servo surface generates servo feedback light based on the servo light. The servo feedback light is reflected back to objective lens a62 and then transmitted through objective lens a62 to polarizing beam splitter a52. Polarizing beam splitter a52 reflects the servo feedback light towards light receiver a72. Light receiver a72 detects the servo feedback light and obtains a photosensitive signal of the servo light. This photosensitive signal carries the position information of the servo light spot to indicate the illumination position of the servo light on the servo surface. To facilitate the distinction between servo light and servo feedback light, Figure 6 The servo light and servo feedback light are shown separately in the illustration, but this is not intended to limit the positions of the servo light and servo feedback light. The positions of the servo light and servo feedback light may overlap or may not overlap. This application does not specifically limit them.

[0059] Optionally, the light transmitted through the polarizing beam splitter may also need to pass through a movable compensating lens (MCL) to adjust the focal length. When light needs to be redirected to the objective lens by changing its optical path, a right-angle prism (RAP) can be used to alter the light path, such as... Figure 6 The middle right-angle prism a81 and right-angle prism a82. In addition, the light may need to pass through a quarter-wave plate (QWA) before entering the objective lens, so that when the light passes through perpendicularly, the phase difference between the ordinary light and the abnormal light is controlled to 1 / 4 wavelength.

[0060] The polarizing beam splitters a51 and a52 can be polarization beamsplitters (PBS), used to transmit or reflect incident light according to its polarization direction. The laser emitter a1 can be a laser diode (LD). In some embodiments, the laser emitter a1 can be replaced by a laser emitter array, which can emit a write light array or a read light array, thereby enabling the writing or reading of multiple data items to or from the fluorescent optical disc 100 at once, increasing the data read / write efficiency of the fluorescent optical disc. The write light array includes multiple write beams, and the read light array includes multiple read beams.

[0061] The above Figure 6 The example shown illustrates the sharing of some optoelectronic components between the read / write optical path and the servo optical path. For instance, the read / write optical path and the servo optical path share the laser emitter a1, collimator a2, shaping prism a3, and beam splitter a4, in which case the read / write light and the servo light are coaxial. In other embodiments, the read / write optical path and the servo optical path may also use separate optical paths and not share optoelectronic components.

[0062] The process of reading and writing data from a fluorescent optical disc is a dynamic process of continuously focusing a laser onto the fluorescent optical disc 100 and adjusting the focusing position based on the focusing result. This dynamic process requires multiple adjustments to the objective lens, and the process from each adjustment to the next adjustment is called an adjustment process. Each adjustment process includes: the servo control unit controlling the objective lens to focus servo light onto the fluorescent optical disc 100 based on a servo control signal; the photoreceiver receiving the light signal fed back from the fluorescent optical disc 100, converting the light signal into a discrete servo error signal, and providing this servo error signal to the signal processing unit; the signal processing unit converting the discrete servo error signal into a continuous servo error signal, and providing this servo error signal to the servo control unit; and the servo control unit obtaining a servo control signal based on this servo error signal, so that the objective lens can be adjusted based on this servo control signal in the next adjustment process, so that the objective lens focuses the servo light onto the fluorescent optical disc 100. The process of the servo control unit focusing the objective lens based on the servo control signal can be as follows: the servo control unit 21 controls the torque device to move the objective lens c2 in the servo direction of the fluorescent optical disc 100 based on the servo control signal, so that the servo light can be irradiated onto the servo surface.

[0063] Since writing data to the fluorescent optical disc 100 relies on a laser to change the medium on the surface of the information layer 12, the fluorescent optical disc 100 appears as multiple independent information points. Furthermore, the fluorescent optical disc 100 rotates continuously during the read / write process, and in each adjustment process, the read / write light sweeps across multiple information points located at different positions. Therefore, the electrical signals corresponding to the laser-excited read / write feedback light of these information points are discrete signals. Correspondingly, the servo light sweeps across multiple target point positions. Ideally, the servo light illuminates the center position of the track in the servo surface, which is the target point position. Therefore, the servo feedback light generated in each adjustment process includes multiple feedback beams fed back from multiple target point positions. Accordingly, the servo error signal converted by the light receiver is actually multiple discrete signals corresponding to multiple feedback beams. Thus, the discrete servo error signal reflects the distance between the servo light spot position on the fluorescent optical disc and the target point position. However, the servo control unit can only process continuous signals, so a signal processing unit is needed to convert the discrete signal into a continuous signal.

[0064] Furthermore, the servo light guides the read / write light through two processes: focusing and tracking. Focusing is the process of adjusting the read / write light to be focused onto the information layer surface. Tracking is the process of adjusting the read / write light to illuminate the center of the information layer track. In the servo process of the servo light guiding the read / write light, the light is usually focused onto the information layer surface first, and then adjusted to illuminate the center of the track on the information layer; that is, the focusing process is performed first, followed by the tracking process. Both the focusing and tracking processes are used to adjust the laser from an inaccurate focus position to an accurate one. Error signals are generated in both processes, and these error signals guide the next adjustment during the adjustment process. The error signal generated during the focusing process is called the focus error signal (FE), which indicates the distance between the servo light spot position and the servo surface. The error signal generated during the tracking process is called the tracking error signal (TE), which indicates the distance between the servo light spot position and the center of the track on the servo surface. Since the servo control method for fluorescent optical discs provided in this application can be used for both the focusing process and the tracking process, for ease of description, the focusing error signal and the tracking error signal are collectively referred to as the servo error signal.

[0065] As described above, the process of reading and writing data from a phosphor optical disc is a dynamic process involving multiple adjustment processes. The following explanation uses the processing of servo feedback light generated during one adjustment process as an example to illustrate the implementation process of the servo control method for a phosphor optical disc provided in this application. Figure 7 As shown, the servo control method for this fluorescent optical disc includes the following steps:

[0066] Step 701: The servo control unit controls the optical processing unit based on the initial servo control signal, so that the servo light is focused onto the servo surface of the fluorescent optical disc by the objective lens in the optical processing unit.

[0067] During each adjustment process, the objective lens can be controlled using the corresponding servo control signal to focus the servo light onto the servo surface of the fluorescent optical disc. It should be noted that during the adjustment process, the servo light may or may not accurately illuminate the servo surface. Here, "focusing the servo light onto the servo surface of the fluorescent optical disc via the objective lens in the optical processing unit" means that the control objective of the servo control unit is to ensure that the servo light illuminates the servo surface via the objective lens.

[0068] Step 702: The optical receiver receives the servo feedback light from the fluorescent optical disc to the servo light, obtains multiple first servo error signals based on the servo feedback light, and provides multiple first servo error signals to the second signal processing unit. The first servo error signals are used to indicate the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc.

[0069] After the servo light shines on the fluorescent optical disc, the disc provides feedback, and the optical receiver receives the servo feedback light. As described above, the servo feedback light generated in each adjustment process includes multiple feedback beams fed back from multiple target locations. Therefore, the first servo error signal is actually multiple discrete signals corresponding to the multiple feedback beams, and each first servo error signal is a discrete signal. The first servo error signal can be represented as x(n), where n indicates the target location providing the feedback beam. Then, the first servo error signal x(i) represents the distance between the spot position of the servo light in the current adjustment process and the i-th target location swept during the current adjustment process.

[0070] The optical receiver can obtain a corresponding first servo error signal based on the light intensity of the feedback beam and provide this first servo error signal to the second signal processing unit. The first servo error signal is actually an electrical signal, and its voltage value characterizes the light intensity of the feedback beam. During focusing, the first servo error signal is a focusing error signal, and its voltage value indicates the magnitude of the deviation of the servo light's focus from the surface of the servo surface. The smaller the voltage value of the focusing error signal, the less the servo light's focus deviates from the surface of the servo surface, and the more accurately the servo light beam is focused. Ideally, when the servo light beam is focused on the surface of the servo surface, the voltage value of the focusing error signal is zero. During tracking, the first servo error signal is a tracking error signal, and its voltage value indicates the magnitude of the deviation of the servo light's focus from the center position of the servo surface's track. The smaller the voltage value of the tracking error signal, the less the servo light's focus deviates from the center position of the servo surface's track, and the more accurately the servo light beam is tracked. Ideally, when the servo light beam is tracked at the center position of the servo surface's track, the voltage value of the tracking error signal is zero.

[0071] In one implementation, the optical receiver has multiple independent receiving areas. The optical receiver can obtain a first servo error signal based on the light intensity of the feedback beam received by the multiple receiving areas. For example, the optical receiver has multiple independent receiving areas. After receiving the feedback beam, the optical receiver can acquire the light intensity of the feedback beam received by each of the multiple receiving areas, obtain the voltage value of the focusing error signal using the astigmatism method, and obtain the voltage value of the tracking error signal using the push-pull method.

[0072] Step 703: The second signal processing unit divides the multiple first servo error signals into multiple signal sets based on the voltage values ​​of the multiple first servo error signals, and provides the multiple signal sets to the third signal processing unit.

[0073] After receiving multiple first servo error signals, the second signal processing unit divides these signals into multiple signal sets. Then, the second signal processing unit can provide these multiple signal sets to the third signal processing unit, enabling the third signal processing unit to process the first servo error signals based on these multiple signal sets.

[0074] In one implementation, the second signal processing unit can perform feature analysis based on the voltage values ​​of multiple first servo error signals, and then divide the multiple first servo error signals into multiple signal sets based on the distribution of their voltage values. For example, the second signal processing unit can determine the proximity of the voltage values ​​of the multiple first servo error signals based on their distribution, and based on this proximity, group the first servo error signals with similar voltage values ​​into the same signal set, and group the first servo error signals with significantly different voltage values ​​into different signal sets. When the voltage values ​​of multiple first servo error signals are relatively close, it indicates that the content represented by the multiple first servo error signals has a high degree of commonality, so they can be grouped into the same signal set. When the voltage values ​​of multiple first servo error signals differ significantly, it indicates that the content represented by the multiple first servo error signals differs significantly, so they can be grouped into different signal sets. The implementation method for determining the proximity of the voltage values ​​of the first servo error signals can be determined according to application requirements. For example, when determining whether two first servo error signals are close, the difference in voltage values ​​between the two first servo error signals can be obtained. If the difference in voltage values ​​is less than a difference threshold, the voltage values ​​of the two first servo error signals are determined to be close; if the difference in voltage values ​​is greater than or equal to the difference threshold, the voltage values ​​of the two first servo error signals are determined to be significantly different. Furthermore, different difference thresholds can be used to measure whether the voltage values ​​are close or significantly different. For example, if the difference in voltage values ​​is less than a first difference threshold, the voltage values ​​of the two first servo error signals are determined to be close; if the difference in voltage values ​​is greater than or equal to a second difference threshold, the voltage values ​​of the two first servo error signals are determined to be significantly different. Additionally, the difference thresholds used to measure whether the voltage values ​​are close or significantly different can be preset or determined by analyzing multiple first servo error signals and considering the distribution of their voltage values. This application does not specifically limit the specific thresholds used. In addition, when dividing multiple first servo error signals into multiple signal sets, it is also necessary to ensure that every two first servo error signals in the same signal set are relatively close, and that the voltage values ​​of the first servo error signals in different signal sets differ significantly.

[0075] It should be noted that this process of dividing the signal sets can be a multi-round iterative process. For example, in the division process, a difference threshold can be determined first among the voltage values ​​of multiple first servo error signals, and the multiple first servo error signals can be divided into two signal sets based on this difference threshold. Then, based on the voltage values ​​of the first servo error signals in the two signal sets, the difference thresholds corresponding to these two signal sets can be determined respectively. Then, the two signal sets can be further subdivided according to the difference thresholds corresponding to each signal set, and so on, to obtain multiple signal sets. Similarly, when using different difference thresholds to measure whether the voltage values ​​are close and the voltage values ​​differ significantly, a first difference threshold and a second difference threshold can be determined first, and the multiple first servo error signals can be divided into two signal sets based on the first difference thresholds and the second difference thresholds. Then, based on the voltage values ​​of the first servo error signals in the two signal sets, the difference thresholds corresponding to these two signal sets can be determined respectively. Then, the two signal sets can be further subdivided according to the difference thresholds corresponding to each signal set, and so on, to obtain multiple signal sets.

[0076] In one implementation, step 703 can be implemented using a back propagation (BP) neural network. For example, multiple first servo error signals can be represented as an image, and this image can be input into the BP neural network. The BP neural network performs feature analysis on the voltage values ​​of the multiple first servo error signals and, based on these features, divides the multiple first servo error signals into multiple signal sets. This BP neural network can be pre-trained using a training set. The pre-training result can indicate multiple voltage ranges. When performing step 703, the multiple first servo error signals can be divided into multiple signal sets based on these multiple voltage ranges. For example, when performing step 703, the multiple voltage ranges obtained from the pre-training can be fine-tuned based on the analysis results of the multiple first servo error signals. When the voltage value of a first servo error signal conforms to a certain voltage range obtained from the fine-tuning, the first servo error signal is divided into the signal set corresponding to that voltage range, thereby dividing the multiple first servo error signals into multiple signal sets.

[0077] The pre-trained BP neural network can obtain multiple voltage ranges, which are used to indicate the actual feedback light of the fluorescent optical disc to the servo light. When performing feature analysis on multiple first servo error signals using the pre-trained BP neural network, the BP neural network can also filter out first servo error signals whose voltage values ​​do not match the multiple voltage ranges, thereby removing noise points and pulse misjudgments caused by spikes or dips. Then, the signal set is divided based on the multiple first servo error signals after removing noise points and pulse misjudgments to ensure that the signal-processed first servo error signals can accurately reflect the servo error and improve the accuracy of servo control based on the first servo error signals. In one implementation, the BP neural network can filter out first servo error signals whose voltage values ​​do not fall within the multiple voltage ranges, or filter out first servo error signals whose voltage values ​​are specified multiples of the maximum and minimum voltage values ​​within the multiple voltage ranges. Figure 8 As shown, Figure 8 The size of the dot represents the voltage value of the corresponding first servo error signal. Based on the multiple voltage ranges of the BP neural network, it can be seen that the voltage value of the dot represented by the dashed circle is significantly different from the voltage values ​​of other dots. Therefore, the dot represented by the dashed circle can be identified as a noise point. The multiple first servo error signals after removing the noise points are as follows: Figure 9 As shown.

[0078] Step 704: The third signal processing unit obtains the voltage threshold of multiple signal sets based on the voltage value of the first servo error signal in multiple signal sets, adjusts the voltage of the first servo error signal in any signal set based on the voltage threshold of any signal set, and provides the adjusted multiple signal sets to the first signal processing unit.

[0079] After receiving multiple signal sets provided by the second signal processing unit, the third signal processing unit can obtain a voltage threshold for the signal set based on the voltage value of the first servo error signal in any one of the signal sets. Then, based on this voltage threshold, it can adjust the voltage value of the first servo error signal in the signal set. For example, for any given signal set, if the multiple first servo error signals are relatively close and likely represent the same content, after obtaining the voltage threshold, the voltage values ​​of all the first servo error signals in the signal set can be adjusted to equal the voltage threshold, so that the adjusted multiple first servo error signals can represent the same content. That is, the voltage of the adjusted first servo error signal is equal to the voltage threshold of the signal set to which the first servo error signal belongs. For example, suppose... Figure 10The two arcs represent two first servo error signals. The voltage threshold of the signal set containing the first servo error signal on the left is V1, and the voltage threshold of the signal set containing the first servo error signal on the right is V0. Therefore, the amplitude of the first servo error signal on the left can be reduced to make its voltage value equal to V1, and the amplitude of the first servo error signal on the right can be reduced to make its voltage value equal to V0. The waveforms of the two adjusted first servo error signals are as follows: Figure 11 As shown.

[0080] In one implementation, the third signal processing unit can statistically analyze the voltage values ​​of first servo error signals in multiple signal sets. Based on the voltage values ​​of the first servo error signals in the same signal set, it can obtain the voltage coverage range of the first servo error signals in that signal set. Then, based on the voltage span of the voltage coverage range, it can determine the voltage threshold of the signal set. For example, when the voltage values ​​of multiple first servo error signals in the signal set are relatively evenly distributed, the median line of the voltage coverage range can be determined as the voltage threshold of the signal set. Alternatively, the distribution density of the voltage values ​​of multiple first servo error signals in the signal set can be analyzed, and then this distribution density can be determined as the weight of the corresponding first servo error signal. The weighted sum of the voltage values ​​of the multiple first servo error signals in the signal set can be determined as the voltage threshold of the signal set. The third signal processing unit can also obtain the total number of signal sets provided by the second signal processing unit and obtain the same number of voltage thresholds based on this total number. In one implementation, after obtaining multiple signal sets, the second signal processing unit can statistically analyze the total number of the multiple signal sets and provide this total number to the third signal processing unit. In some scenarios, the total number of signal sets corresponds to the capacity of the fluorescent optical disc; therefore, this total number is also called the order. Alternatively, after receiving multiple signal sets from the second signal processing unit, the third signal processing unit can obtain the total number of these signal sets statistically.

[0081] Optionally, step 704 can be implemented using a U-net neural network. The U-net neural network is a type of convolutional neural network (CNN). In one implementation, multiple signal sets can be input into the U-net neural network, allowing it to perform feature analysis on the voltage values ​​of the first servo error signal in each signal set, and determine the voltage threshold for that signal set based on the analysis results. The U-net neural network can be pre-trained using a training set. The pre-training results can indicate the voltage thresholds for multiple training signal sets. When performing step 704, the voltage thresholds for multiple signal sets can be determined based on the voltage values ​​of the first servo error signal in each signal set. For example, when performing step 704, the voltage thresholds for the pre-trained multiple training signal sets can be fine-tuned based on the analysis results of the voltage values ​​of the first servo error signal in each signal set, and the voltage thresholds for the corresponding signal sets can be determined based on the fine-tuned voltage thresholds, thereby obtaining the voltage thresholds for multiple signal sets.

[0082] Step 705: The first signal processing unit obtains a second servo error signal based on the adjusted multiple signal sets and provides the second servo error signal to the servo control unit. The second servo error signal is used to indicate the change in the distance between the servo light spot position on the fluorescent optical disc and the target position on the fluorescent optical disc over time.

[0083] In one implementation, after receiving the adjusted multiple signal sets, the first signal processing unit can acquire the timing of multiple first servo error signals. Then, based on the voltage values ​​of any two time-adjacent first servo error signals, it predicts the trend of voltage value change between the generation times of these two time-adjacent signals. Based on this trend and the multiple first servo error signals, it obtains the second servo error signal. For example, according to the timing relationship indicated by the generation times of the first servo error signals in the adjusted multiple signal sets, the first signal processing unit first sorts all the first servo error signals in the multiple signal sets according to their timing order. Then, based on the voltage values ​​of any two adjacent first servo error signals in the sorted queue, it predicts the trend of voltage value change over time between the generation times of these two first servo error signals, and fills the gap between the waveforms of these two first servo error signals with a voltage waveform indicating this trend. This process is repeated for each pair of adjacent first servo error signals in the sorted queue to obtain the second servo error signal. The second servo error signal is used to indicate how the distance between the servo light spot position on the fluorescent optical disc and the target position on the fluorescent optical disc changes over time. It can be seen that the second servo error signal is actually a continuous signal that changes over time. Therefore, step 705 is essentially to obtain the second servo error signal, which is a continuous signal, based on multiple first servo error signals that are presented as discrete signals.

[0084] In one implementation, step 705 can be implemented using a long short-term memory (LSTM) neural network. Please refer to the documentation for the structure of an LSTM neural network. Figure 12 Here, X(t-1), X(t), and X(t+1) are the inputs of the LSTM neural network at times t-1, t, and t+1, respectively, representing the adjusted sets of signals received at times t-1, t, and t+1. h(t-1), h(t), and h(t+1) are the outputs of the hidden layers of the LSTM neural network at times t-1, t, and t+1, respectively, representing the second servo error signals obtained at times t-1, t, and t+1. Please refer to [reference needed]. Figure 12The LSTM neural network primarily functions through three gates: the forget gate, the input gate, and the output gate. The forget gate determines which information to discard from the cell state. A threshold δ1 controls the amount of data passing through this gate, with δ1 ranging from [0, 1]. δ1 = 0 indicates "complete retention," and δ1 = 1 indicates "complete discard." The input gate determines which new information needs to be stored in the cell state. This is achieved through an input threshold layer (δ2) and a tanh1 layer. The input threshold layer (δ2) determines which values ​​to update, and the tanh1 layer creates new candidate vectors and adds them to the cell state. The output gate determines the output, achieved through an output threshold layer (δ3) and a tanh2 layer. The output threshold layer (δ3) determines which parts of the cell state need to be output, and the tanh2 layer processes the cell state and outputs a value ranging from [-1, 1]. The output of this output gate is the product of the output of the output threshold layer (δ3) and the output of the tanh2 layer. Optionally, the values ​​of δ1, δ2 and δ3 can be set according to actual needs.

[0085] By using an LSTM neural network based on an adjusted signal set, a second servo error signal, which is presented as a continuous signal, can be obtained. The advantages of LSTM neural networks in recognizing and predicting continuous signals, as well as their long short-term memory function, can be utilized to train and learn on a dataset of possible error signals. By continuously measuring the first servo error signal corresponding to different target positions, and then using deep learning technology to identify and predict discrete signals in the time domain, discrete signals can be converted into continuous signals, and a high-precision second servo error signal that meets the requirements of servo control can be obtained.

[0086] Step 706: The servo control unit obtains the adjusted servo control signal based on the second servo error signal.

[0087] After receiving the second servo error signal provided by the first signal processing unit, the servo control unit can obtain an adjusted servo control signal based on the second servo error signal and the current position of the objective lens. This allows the servo control unit to control the objective lens according to the adjusted servo control signal in the next adjustment process, so that the objective lens focuses the servo light onto the servo surface of the fluorescent optical disc.

[0088] Optionally, before obtaining the servo control signal based on the second servo error signal, the servo control unit can adaptively adjust the second servo error signal to reduce its error, thereby ensuring the accuracy of the adjusted servo control signal obtained based on the second servo error signal and focusing the servo light more accurately on the servo surface of the fluorescent optical disc. In one implementation, the servo control unit may include a lead-lag controller, which can be used to adaptively adjust the second servo error signal. For example, Figure 13 This is a schematic diagram of a lead-lag controller provided in an embodiment of this application. Figure 13 As shown, the input of the lead-lag controller is the second servo error signal, and the output is the adjusted second servo error signal. The transfer function G(s) of the lead-lag controller satisfies the following equation:

[0089]

[0090] Optionally, Figure 14 This is a schematic diagram of another lead-lag controller provided in an embodiment of this application. Figure 14 As shown, the lead-lag controller includes a repetitive control element and a lead-lag control element, compared to... Figure 13 The illustrated lead-lag controller incorporates a repetitive control element. This repetitive control element first performs multiple rounds of automatic adjustment on the second servo error signal, and then provides the adjusted second servo error signal to the lead-lag control element, thereby further improving the accuracy of the adjusted second servo error signal. Figure 14 The lead-lag controller transfer function G(s) shown satisfies the following equation:

[0091]

[0092] Where Cr(s) is the transfer function of the repetitive control loop, which satisfies:

[0093] Furthermore, the servo control unit may also include a proportional (P), integral (I), and derivative (D) controller (PID controller). The input to the PID controller is the second servo error signal, and the output is the second servo error signal adjusted by the PID controller. Moreover, when the servo control unit also includes a PID controller, the second servo error signal can be adjusted first using the PID controller, and then the lead-lag controller can be used to further adjust the second servo error signal. In one implementation, the PID controller can be a fuzzy adaptive PID controller. Because the fuzzy adaptive PID controller can adjust the PID parameters in real time, it can more accurately adjust the second servo error signal. Figure 15This is a schematic diagram of the structure of a fuzzy adaptive PID controller provided in an embodiment of this application.

[0094] As can be seen from the above, in the servo control method for a fluorescent optical disc provided in this application embodiment, the servo control unit can control the optical processing unit based on an initial servo control signal, focusing the servo light onto the servo surface of the fluorescent optical disc via the optical processing unit. Then, the light receiver can receive the servo feedback light from the fluorescent optical disc to the servo light, and obtain multiple first servo error signals based on the servo feedback light, providing these multiple first servo error signals to the first signal processing unit. Then, the first signal processing unit obtains a second servo error signal based on the multiple first servo error signals. Since the first servo error signal is used to indicate the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc, this first servo error signal is a discrete signal. The second servo error signal is used to indicate how the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc changes over time. This second servo error signal is a continuous signal. Through the processing of the first servo error signal by the first signal processing unit, the first servo error signal is converted into a second servo error signal that is presented as a continuous signal. After the first signal processing unit provides the second servo error signal to the servo control unit, the servo control unit can obtain the adjusted servo control signal based on the second servo error signal, which is presented as a continuous signal.

[0095] In this way, during the servo control process, considering that the servo feedback light from the fluorescent optical disc is discrete, the discrete servo feedback light can be converted into a continuous second servo error signal through the processing of the optical receiver and the first signal processing unit. This eliminates the need to use a method where the servo light feedback signal is continuous for servo control, effectively improving the accuracy of servo control based on the servo feedback light from the fluorescent optical disc, and helping to improve the read and write characteristics of the fluorescent optical disc.

[0096] When neural networks are used to implement the first, second, and / or third signal processing units, the advantages of neural networks can be leveraged to improve signal processing speed and the speed of reading and writing data from fluorescent optical discs. This allows the method to be applied to reading scenarios in high-speed optical discs or high-density fluorescent storage systems. Similarly, those skilled in the art can also apply the servo control method provided in the embodiments of this application to the processing and classification of high-speed discrete signals, for example, in encoding the location of information spots and their signal amplitude changes, or in determining the threshold voltage during high-frequency pulse counting.

[0097] Furthermore, when the neural network used to implement the first signal processing unit, the second signal processing unit, and / or the third signal processing unit is a pre-trained neural network, it is possible to improve the classification accuracy by using a large amount of data training, and enable the neural network to be used continuously after the dataset training is established without adjusting the parameters, thereby improving the ease of implementation of the servo control method.

[0098] It should be noted that the order of steps in the servo control method for fluorescent optical discs provided in this application can be appropriately adjusted, and steps can be added or removed as needed. Any variations that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application, and therefore will not be elaborated further.

[0099] The above describes the servo control method for a fluorescent optical disc according to embodiments of this application. Corresponding to the above method, embodiments of this application also provide a servo control device. A schematic diagram of the servo control device is shown below. Figure 4 and Figure 5 As shown. It should be understood that the servo control device may include more additional units than the structure shown, or may omit some of the units shown, and the embodiments of this application do not impose any limitations on this. Figure 4 As shown, the servo control device includes: a servo control unit, an optical processing unit, an optical receiver, and a first signal processing unit.

[0100] The servo control unit is used to control the optical processing unit based on the servo control signal, so that the servo light is focused onto the servo surface of the fluorescent optical disc by the optical processing unit.

[0101] The optical receiver is used to receive the servo feedback light from the fluorescent optical disc to the servo light, obtain multiple first servo error signals based on the servo feedback light, and provide multiple first servo error signals to the first signal processing unit. The first servo error signals are used to indicate the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc.

[0102] The first signal processing unit is used to obtain a second servo error signal based on multiple first servo error signals, and to provide the second servo error signal to the servo control unit. The second servo error signal is used to indicate the change in the distance between the servo light spot position on the fluorescent optical disc and the target position on the fluorescent optical disc over time.

[0103] The servo control unit is also used to obtain an adjusted servo control signal based on the second servo error signal.

[0104] Optionally, the first signal processing unit is specifically configured to: acquire the timing of multiple first servo error signals; predict the change trend of the voltage value between the generation times of any two time-adjacent first servo error signals based on the voltage values ​​of any two time-adjacent first servo error signals; and obtain a second servo error signal based on the change trend and the multiple first servo error signals.

[0105] Optionally, the device further includes a second signal processing unit. The second signal processing unit is configured to: receive a plurality of first servo error signals provided by the optical receiver; divide the plurality of first servo error signals into a plurality of signal sets; and provide the plurality of signal sets to the first signal processing unit.

[0106] Optionally, the second signal processing unit is specifically used to: divide the multiple first servo error signals into multiple signal sets based on the distribution of voltage values ​​of the multiple first servo error signals.

[0107] Optionally, the device further includes a third signal processing unit. The third signal processing unit is configured to: receive multiple signal sets provided by the second signal processing unit; obtain a voltage threshold for any signal set based on the voltage value of a first servo error signal in any signal set; adjust the voltage of the first servo error signal in any signal set based on the voltage threshold to obtain adjusted multiple signal sets; and provide the adjusted multiple signal sets to the first signal processing unit.

[0108] Optionally, the third signal processing unit is specifically used to: obtain the voltage coverage range of the first servo error signal in any signal set based on the voltage value of the first servo error signal in any signal set; and determine the voltage threshold of any signal set based on the voltage coverage range of any signal set.

[0109] Optionally, the voltage of the adjusted first servo error signal is equal to the voltage threshold of the signal set to which the first servo error signal belongs.

[0110] Optionally, the light receiving unit is a photomultiplier tube.

[0111] Based on the above-mentioned implementation methods, further combinations can be made to provide even more implementation methods.

[0112] As can be seen from the above, in the servo control device for a fluorescent optical disc provided in this application embodiment, the servo control unit can control the optical processing unit based on an initial servo control signal to focus the servo light onto the servo surface of the fluorescent optical disc. Then, the light receiver can receive the servo feedback light from the fluorescent optical disc to the servo light, and obtain multiple first servo error signals based on the servo feedback light, and provide these multiple first servo error signals to the first signal processing unit. Then, the first signal processing unit obtains a second servo error signal based on the multiple first servo error signals. Since the first servo error signal is used to indicate the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc, this first servo error signal is a discrete signal. The second servo error signal is used to indicate how the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc changes over time. This second servo error signal is a continuous signal. Through the processing of the first servo error signal by the first signal processing unit, the first servo error signal is converted into a second servo error signal that is presented as a continuous signal. After the first signal processing unit provides the second servo error signal to the servo control unit, the servo control unit can obtain the adjusted servo control signal based on the second servo error signal, which is presented as a continuous signal.

[0113] In this way, during the servo control process, considering that the servo feedback light from the fluorescent optical disc is discrete, the discrete servo feedback light can be converted into a continuous second servo error signal through the processing of the optical receiver and the first signal processing unit. This eliminates the need to use a method where the servo light feedback signal is continuous for servo control, effectively improving the accuracy of servo control based on the servo feedback light from the fluorescent optical disc, and helping to improve the read and write characteristics of the fluorescent optical disc.

[0114] When a neural network is used to implement the first, second, and / or third signal processing units, the advantages of neural networks can be leveraged to improve signal processing speed and the speed of reading and writing data from fluorescent optical discs. This allows the device to be applied to reading scenarios in high-speed optical discs or high-density fluorescent storage systems. Similarly, those skilled in the art can also apply the concept of the servo control device provided in the embodiments of this application to the processing and classification of high-speed discrete signals, for example, in encoding the location of information spots and their signal amplitude changes, or in determining the threshold voltage during high-frequency pulse counting.

[0115] Furthermore, when the neural network used to implement the first signal processing unit, the second signal processing unit, and / or the third signal processing unit is a pre-trained neural network, it is possible to improve the classification accuracy by using a large amount of data training, and enable the neural network to be used continuously after the dataset training is established without adjusting the parameters, thereby improving the ease of implementation of the servo control device.

[0116] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of each unit described above can be referred to the corresponding content in the foregoing method embodiments, and will not be repeated here.

[0117] This application provides a data read / write device. This data read / write device performs some or all of the functions of the servo control device provided in this application. For example, the data read / write device controls each unit in the servo control device of a fluorescent optical disc to execute the corresponding method in the servo control method of the fluorescent optical disc. Figure 16 This is a schematic diagram of the structure of a data read / write device provided in an embodiment of this application. Figure 16 As shown, the data read / write device 1600 includes a processor 1601, a memory 1602, a communication interface 1603, and a bus 1604. The processor 1601, memory 1602, and communication interface 1603 are interconnected via the bus 1604.

[0118] Processor 1601 may include a general-purpose processor and / or a dedicated hardware chip. The general-purpose processor may include a central processing unit (CPU), a microprocessor, or a graphics processing unit (GPU). The CPU may be a single-core processor or a multi-core processor. The dedicated hardware chip is a high-performance processing hardware module. The dedicated hardware chip includes at least one of a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a network processor (NP). Processor 1601 may also be an integrated circuit chip with signal processing capabilities. In implementation, some or all of the functions of the phosphor optical disc servo control method of this application may be implemented through the integrated logic circuitry in the hardware of processor 1601 or through software instructions.

[0119] Memory 1602 is used to store computer programs, including an operating system 1602a and executable code (i.e., program instructions) 1602b. Memory 1602 may be, for example, a read-only memory or other type of static storage device capable of storing static information and instructions; or a random access memory or other type of dynamic storage device capable of storing information and instructions; or an electrically erasable programmable read-only memory, a read-only optical disc or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), a magnetic disk storage medium, or other magnetic storage device; or any other medium capable of carrying or storing desired executable code in the form of instructions or data structures and accessible by a computer, but not limited thereto. For example, memory 1602 may be used to store output port queues, etc. Memory 1602 may exist independently and be connected to processor 1601 via bus 1604. Alternatively, memory 1602 and processor 1601 may be integrated together. The memory 1602 can store executable code. When the executable code stored in the memory 1602 is executed by the processor 1601, the processor 1601 performs some or all of the functions of the servo control method for the fluorescent optical disc provided in this application embodiment. Please refer to the relevant descriptions in the foregoing embodiments for the implementation method of the processor 1601 executing this process. The memory 1602 may also include other software modules and data required for running processes, such as the operating system.

[0120] The communication interface 1603 uses a transceiver module, such as, but not limited to, a transceiver, to enable communication with other devices or communication networks. For example, the communication interface 1603 can be any one or any combination of the following devices: a network interface (such as an Ethernet interface), a wireless network card, or other devices with network access capabilities.

[0121] Bus 1604 is any type of communication bus used to interconnect internal devices (e.g., memory 1602, processor 1601, communication interface 1603) of the data read / write device. For example, a system bus. This embodiment illustrates the interconnection of the aforementioned devices within the data read / write device via bus 1604. Optionally, the aforementioned devices within the data read / write device 1600 can also communicate with each other using other connection methods besides bus 1604. For example, the aforementioned devices within the data read / write device 1600 can be interconnected through internal logic interfaces.

[0122] It should be noted that the aforementioned devices can be disposed on separate chips, or at least partially or entirely on the same chip. Whether to dispose of the devices independently on different chips or integrate them on one or more chips often depends on the needs of the product design. This application does not limit the specific implementation of the aforementioned devices. Furthermore, the descriptions of the processes corresponding to the various figures above each have their own emphasis; for parts of a process not described in detail in one figure, please refer to the relevant descriptions of other processes.

[0123] In the above embodiments, the implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, in the form of a computer program product. The computer program product providing the program development platform includes one or more computer instructions. When these computer program instructions are loaded and executed on a data read / write device, they fully or partially implement some or all of the functions of the servo control method for the fluorescent optical disc provided in the embodiments of this application.

[0124] Furthermore, computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium stores computer program instructions that provide a program development platform.

[0125] This application also provides a computer-readable storage medium, which is a non-volatile computer-readable storage medium. The computer-readable storage medium includes program instructions that, when executed on a data reading and writing device, cause the data reading and writing device to implement the servo control method for a fluorescent optical disc as provided in this application embodiment.

[0126] This application also provides a computer program product containing instructions, which, when run on a computer, enables the computer to implement the servo control method for fluorescent optical discs provided in this application.

[0127] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware, or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0128] It should be noted that all information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.), and signals involved in this application have been authorized by the user or fully authorized by all parties, and the collection, use, and processing of related data must comply with the relevant laws, regulations, and standards of the relevant countries and regions. For example, the information and executable code involved in this application were obtained with full authorization.

[0129] In the embodiments of this application, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "at least one" refers to one or more, and the term "multiple" refers to multiples, unless otherwise expressly defined.

[0130] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0131] It should be understood that the terminology used in the description of the various examples herein is for the purpose of describing the particular examples only and is not intended to be limiting. As used in the description of the various examples and the appended claims, the singular forms “a” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0132] It should also be understood that, in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0133] The above are merely optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the concept and principles of this application should be included within the protection scope of this application.

Claims

1. A servo control method for a fluorescent optical disc, characterized in that, The method is applied to a servo control device for a fluorescent optical disc, the servo control device comprising: a servo control unit, an optical processing unit, a light receiver, and a first signal processing unit, the method comprising: The servo control unit controls the optical processing unit based on the servo control signal, so that the servo light is focused on the servo surface of the fluorescent optical disc by the optical processing unit; The optical receiver receives the servo feedback light from the fluorescent optical disc to the servo light, obtains a plurality of first servo error signals based on the servo feedback light, and provides the plurality of first servo error signals to the first signal processing unit. The first servo error signals are used to indicate the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc. The first signal processing unit obtains a second servo error signal based on the plurality of first servo error signals and provides the second servo error signal to the servo control unit. The second servo error signal is used to indicate how the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc changes over time. The servo control unit obtains the adjusted servo control signal based on the second servo error signal.

2. The method as described in claim 1, characterized in that, The first signal processing unit obtains a second servo error signal based on the plurality of first servo error signals, including: The first signal processing unit acquires the timing sequence of the plurality of first servo error signals; The first signal processing unit predicts the trend of voltage value change between the generation times of any two time-adjacent first servo error signals based on the voltage values ​​of any two time-adjacent first servo error signals. The first signal processing unit obtains the second servo error signal based on the changing trend and the plurality of first servo error signals.

3. The method as described in claim 1 or 2, characterized in that, The servo control device for the fluorescent optical disc further includes: a second signal processing unit, and the method further includes: The second signal processing unit receives the plurality of first servo error signals provided by the optical receiver; The second signal processing unit divides the plurality of first servo error signals into multiple signal sets; The second signal processing unit provides the plurality of signal sets to the first signal processing unit.

4. The method as described in claim 3, characterized in that, The second signal processing unit divides the plurality of first servo error signals into multiple signal sets, including: The second signal processing unit divides the multiple first servo error signals into multiple signal sets based on the distribution of voltage values ​​of the multiple first servo error signals.

5. The method as described in claim 3, characterized in that, The servo control device for the fluorescent optical disc further includes: a third signal processing unit, and the method further includes: The third signal processing unit receives the plurality of signal sets provided by the second signal processing unit; The third signal processing unit obtains the voltage threshold of any signal set based on the voltage value of the first servo error signal in any signal set. The third signal processing unit adjusts the voltage of the first servo error signal in any signal set based on the voltage threshold of any signal set, thereby obtaining multiple adjusted signal sets. The third signal processing unit provides the first signal processing unit with adjusted sets of signals.

6. The method as described in claim 5, characterized in that, The third signal processing unit obtains a voltage threshold for any signal set based on the voltage value of the first servo error signal in any signal set, including: The third signal processing unit obtains the voltage coverage range of the first servo error signal in any signal set based on the voltage value of the first servo error signal in any signal set. The third signal processing unit determines the voltage threshold of any signal set based on the voltage coverage range of any signal set.

7. The method as described in claim 5, characterized in that, The adjusted voltage of the first servo error signal is equal to the voltage threshold of the signal set to which the first servo error signal belongs.

8. A servo control device for a fluorescent optical disc, characterized in that, The device includes: a servo control unit, an optical processing unit, a light receiver, and a first signal processing unit; The servo control unit is used to control the optical processing unit based on the servo control signal, so that the servo light is focused on the servo surface of the fluorescent optical disc by the optical processing unit; The optical receiver is used to receive the servo feedback light of the fluorescent optical disc to the servo light, obtain a plurality of first servo error signals based on the servo feedback light, and provide the plurality of first servo error signals to the first signal processing unit. The first servo error signals are used to indicate the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc. The first signal processing unit is used to obtain a second servo error signal based on the plurality of first servo error signals, and to provide the second servo error signal to the servo control unit. The second servo error signal is used to indicate the change in the distance between the spot position of the servo light on the fluorescent optical disc and the target position of the fluorescent optical disc over time. The servo control unit is also used to obtain an adjusted servo control signal based on the second servo error signal.

9. The apparatus as claimed in claim 8, characterized in that, The first signal processing unit is specifically used for: Obtain the timing sequence of the plurality of first servo error signals; Based on the voltage values ​​of any two time-adjacent first servo error signals, predict the trend of voltage value change between the generation times of the two time-adjacent first servo error signals. Based on the changing trend and the plurality of first servo error signals, the second servo error signal is obtained.

10. The apparatus as claimed in claim 8 or 9, characterized in that, The device further includes: a second signal processing unit, the second signal processing unit being used for: Receive the plurality of first servo error signals provided by the optical receiver; The plurality of first servo error signals are divided into multiple signal sets; The plurality of signal sets are provided to the first signal processing unit.

11. The apparatus as claimed in claim 10, characterized in that, The second signal processing unit is specifically used for: Based on the distribution of voltage values ​​of the plurality of first servo error signals, the plurality of first servo error signals are divided into the plurality of signal sets.

12. The apparatus as claimed in claim 10, characterized in that, The device further includes: a third signal processing unit, the third signal processing unit being used for: Receive the plurality of signal sets provided by the second signal processing unit; Based on the voltage value of the first servo error signal in any signal set, obtain the voltage threshold of the any signal set; Based on the voltage threshold of any one of the signal sets, the voltage of the first servo error signal in any one of the signal sets is adjusted to obtain multiple adjusted signal sets; The first signal processing unit is provided with an adjusted set of multiple signals.

13. The apparatus as claimed in claim 12, characterized in that, The third signal processing unit is specifically used for: Based on the voltage value of the first servo error signal in any of the signal sets, the voltage coverage range of the first servo error signal in any of the signal sets is obtained; Based on the voltage coverage range of any signal set, determine the voltage threshold of any signal set.

14. The apparatus as claimed in claim 12, characterized in that, The adjusted voltage of the first servo error signal is equal to the voltage threshold of the signal set to which the first servo error signal belongs.

15. The apparatus as claimed in claim 8, characterized in that, The optical receiver is a photomultiplier tube (PMT).

16. A data reading and writing device for a fluorescent optical disc, characterized in that, The data read / write device includes a servo control device for a fluorescent optical disc as described in any one of claims 8 to 15.

17. A computer program product containing instructions, characterized in that, When the instruction is executed by the data read / write device, the data read / write device performs the method as described in any one of claims 1 to 7.

18. A computer-readable storage medium, characterized in that, It includes computer program instructions, which, when executed by a data read / write device, perform the method as described in any one of claims 1 to 7.

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