Single-servo-layer multi-recording-layer optical disc drive, memory, and electronic device

Abstract

A single-servo-layer multi-recording-layer optical disc drive, a memory, and an electronic device. A dichroic mirror is provided in the optical disc drive. A light beam of a first light source is projected on the surface of one side of the dichroic mirror and then is reflected to a recording medium of an optical disc to read and write data. A light beam of a second light source may directly transmit through the dichroic mirror and be transmitted to a servo layer of the recording medium of the optical disc. The dichroic mirror can be fixed in the optical disc drive by means of a movable assembly. The movable assembly can change the orientation of the dichroic mirror to adjust the relative position between a propagation direction of the light beam of the first light source and a propagation direction of the light beam of the second light source, so as to eliminate errors generated in the processes of installation, use and the like of the optical disc drive. The optical disc drive of the present application has the advantages of small internal structure change, simple implementation process, high control precision and the like, and the effect that while accurate servo of the light beam of the second light source in the servo layer is implemented, the light beam of the first light source is projected to a data track center of each recording layer of the optical disc is realized at low costs.

Description

Single-servo-layer multi-recording-layer optical disc drive, storage device, and electronic device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on August 18, 2023, with application number 202311050409.X and application name “A single-servo layer multi-recording layer optical disc drive, storage and electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of optical discs, and in particular to an optical disc drive, a memory and an electronic device with a single servo layer and multiple recording layers. Background Art

[0003] An optical disc drive is a device used to read and write optical discs. Optical disc drives are typically optional components for computers or other electronic devices, used to read and write various types of optical discs, such as compact discs (CDs), digital versatile discs (DVDs), and Blu-ray discs (BDs). An optical disc drive works by using a laser beam to read and write to the surface of an optical disc. When an optical disc drive reads a disc, the light reflected by the laser beam is detected by a sensor and converted into a digital signal to extract the data on the disc. The optical disc drive can also write data to the disc by adjusting the intensity and focus of the laser beam.

[0004] When writing data on a single-servo-layer, multi-recording-layer optical disc, a conventional optical disc drive uses a pre-pressed single-layer guide layer for servo, while a coaxial blue laser changes its focal depth to record data across multiple recording layers. During installation and use, the directions of the red and blue laser sources may shift, potentially causing them to become misaligned, impacting the quality of data written and read from the drive.

[0005] Summary of the Invention

[0006] To address the aforementioned issues, embodiments of the present application provide a single-servo-layer, multi-recording-layer optical disc drive in which a dichroic mirror is movably fixed within the drive to adjust the relative position of the guide beam and the recording beam, thereby eliminating errors that may occur during installation and use of the drive. Furthermore, the present application provides a memory and electronic device compatible with the single-servo-layer, multi-recording-layer optical disc drive.

[0007] To this end, the following technical solutions are adopted in the embodiments of the present application:

[0008] In a first aspect, an embodiment of the present application provides a single-servo-layer multi-recording-layer optical disc drive, comprising: a first light source for generating a first light beam for reading and writing data on the recording layer; a second light source for generating a second light beam for performing focusing and tracking servo on the servo layer; a propagation direction of the second light beam intersects with a propagation direction of the first light beam; a dichroic mirror is arranged at a position where the propagation direction of the second light beam intersects with the propagation direction of the first light beam, for reflecting the first light beam and transmitting the second light beam; a movable component for movably fixing the dichroic mirror inside the optical disc drive, for changing the orientation of the dichroic mirror to adjust the relative position between the propagation direction of the first light beam and the propagation direction of the second light beam.

[0009] In this embodiment, a dichroic mirror is used to transmit and reflect lasers of different wavelengths, and the dichroic mirror can be designed to be movably fixed inside the optical disc drive. The light beam generated by the second light source can be directly transmitted through the dichroic mirror and will not change its propagation direction as the orientation of the dichroic mirror changes. The light beam generated by the first light source is reflected after being projected onto the surface of the dichroic mirror. The reflected light beam changes its propagation direction as the orientation of the dichroic mirror changes. When the propagation direction of the light beam from the first light source projected onto the optical disc is not coaxial with the propagation direction of the light beam from the second light source projected onto the optical disc, the orientation of the dichroic mirror can be changed by changing the movable component to adjust the propagation direction of the light beam from the first light source projected onto the optical disc. The optical disc drive has the advantages of small changes in internal structure, simple implementation process, and high control accuracy. When the light beam from the second light source is precisely servoed on the servo layer at a relatively low cost, the light beam from the first light source is projected onto the center of the data track of each recording layer of the optical disc.

[0010] In one embodiment, the movable component includes at least one piezoelectric effect actuator, one end of the at least one piezoelectric effect actuator is fixed at different positions of the dichroic mirror, and the other end of the at least one piezoelectric effect actuator is fixed at different positions inside the optical disc drive; the at least one piezoelectric effect actuator is used to change the orientation of the dichroic mirror when receiving an electrical signal.

[0011] In this embodiment, piezoelectric actuators are very common devices with advantages such as low cost, easy control, and precise control. After the dichroic mirrors are fixed inside the optical disc drive via the piezoelectric actuators, changing the dichroic mirrors' orientations simply requires changing the electrical signals flowing into each piezoelectric actuator. This process is very simple and has relatively low control costs.

[0012] In one embodiment, the dichroic mirror includes a frame, which includes two frame structures, one side of the two frame structures is separated from each other, and the opposite side is connected together; the mutually connected side of the two frame structures is fixed inside the optical disc drive; the movable component includes at least one piezoelectric effect driver, which is arranged between the mutually separated side of the two frame structures, and is used to change the orientation of the dichroic mirror when receiving an electrical signal.

[0013] In this embodiment, if the frame of the dichroic mirror includes two frame structures, with one side of the two frame structures separated from each other and one opposite side connected, a piezoelectric effect actuator can be disposed between the separated sides. Changing the orientation of the dichroic mirror can be done by simply changing the electrical signals flowing into each piezoelectric effect actuator, simplifying the entire process and reducing control costs.

[0014] In one embodiment, it further includes: a controller, which is connected to the piezoelectric effect driver respectively, and is used to detect the degree of deviation between the light spot of the first light beam and the light spot of the second light beam, and send an electrical signal of a corresponding value to the piezoelectric effect driver.

[0015] In this embodiment, the controller is a central unit that accurately controls the orientation of the dichroic mirror. It can change the electrical signal flowing into each piezoelectric effect driver according to the deviation between the light spot of the first light beam and the light spot of the second light beam, thereby accurately changing the orientation of the dichroic mirror to adjust the relative position between the first light beam and the second light beam, ensuring that when the servo layer accurately completes servo control, the first light beam used for reading and writing the recording layer always remains at the center of the data track, and can eliminate the deviation caused by different coaxiality of different driver installation errors.

[0016] In one embodiment, the system further includes: a first photodetector configured to receive the first light beam and convert a focusing deviation signal and / or a tracking deviation signal of the first light beam into an electrical signal of a corresponding value.

[0017] In this embodiment, after receiving the first light beam, the first photodetector converts the first light beam into an electrical signal of a corresponding value, thereby detecting the light intensity of the first light beam. The light inlet of the photodetector generally has four quadrants, each equipped with a photodetector. If there is focusing or tracking deviation, the light intensities received by the four quadrants of the photodetector will differ. The photodetector detects the focusing and tracking errors by performing addition and subtraction operations on the different light intensities in the four quadrants.

[0018] In one embodiment, it also includes: a first focus servo circuit and a first tracking servo circuit, wherein the first focus servo circuit is used to adjust the focus position of the first light beam according to the change of the electrical signal corresponding to the focus deviation signal of the first photodetector; the first tracking servo circuit is used to adjust the direction of the first light beam according to the change of the electrical signal corresponding to the tracking deviation signal of the first photodetector.

[0019] In this embodiment, the first focus servo circuit can slightly adjust the displacement of the objective lens based on the change in the light intensity signal of the first light beam, so that the focus of the first light beam can reach an optimal position. The first tracking servo circuit can adjust the direction of the objective lens based on the change in the light intensity signal of the first light beam, so that the objective lens accurately follows the position change of the first light beam, so that the objective lens can maintain the correct direction of the first light beam.

[0020] In one embodiment, it also includes: a first polarization beam splitter, which is arranged at a position in the propagation direction of the first light beam, and is used to split the first light beam into two identical sub-beams, and project one sub-beam to the light inlet of the first photodetector, and project the other sub-beam to the dichroic mirror.

[0021] In this embodiment, the first polarization beam splitter can split the first light beam into two sub-beams with the same intensity, so that the first polarization beam splitter can detect the intensity of the first light beam projected onto the recording medium.

[0022] In one embodiment, the device further includes: a second photodetector configured to receive the second light beam and convert a focusing deviation signal and / or a tracking deviation signal of the second light beam into an electrical signal of a corresponding value.

[0023] In this embodiment, after receiving the second light beam, the second photodetector converts the second light beam into an electrical signal of a corresponding value, thereby detecting the light intensity of the second light beam. If there is focusing or tracking deviation, the light intensities received by the four quadrants of the photodetector will differ. The photodetector detects the focusing and tracking errors by performing addition and subtraction operations on the different light intensities in the four quadrants.

[0024] In one embodiment, it also includes: a second focus servo circuit and a second tracking servo circuit, the second focus servo circuit is used to adjust the focus position of the second light beam according to the change of the electrical signal corresponding to the focus deviation signal of the second photodetector; the second tracking servo circuit is used to adjust the direction of the second light beam according to the change of the electrical signal corresponding to the tracking deviation signal of the second photodetector.

[0025] In this embodiment, the second focus servo circuit can slightly adjust the displacement of the objective lens based on the change in the light intensity signal of the second light beam, so that the focus of the second light beam can reach an optimal position. The second tracking servo circuit can adjust the direction of the objective lens based on the change in the light intensity signal of the second light beam, so that the objective lens accurately follows the position change of the second light beam, so that the objective lens can maintain the correct direction of the second light beam.

[0026] In one embodiment, it also includes: a second polarization beam splitter, which is arranged at a position in the propagation direction of the second light beam, and is used to split the second light beam into two identical sub-beams, and project one sub-beam to the light inlet of the second photodetector, and project the other sub-beam to the dichroic mirror.

[0027] In a second aspect, an embodiment of the present application provides a memory comprising: at least one single-servo-layer multi-recording-layer optical disc, and at least one optical disc drive as may be implemented in the embodiments of the first aspect, for reading and writing data on the at least one single-servo-layer multi-recording-layer optical disc.

[0028] In a third aspect, an embodiment of the present application provides an electronic device comprising: at least one memory as may be implemented in the various embodiments of the second aspect, and at least one controller, respectively connected to the at least one memory, for controlling the at least one memory to read and write data. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The following is a brief introduction to the drawings required for describing the embodiments or prior art.

[0030] FIG1 is a schematic diagram showing the principle of an optical disc drive reading and writing on an optical disc with a single servo layer and multiple recording layers;

[0031] FIG2 is a schematic structural diagram of an optical disc drive in the related art;

[0032] FIG3 is a schematic structural diagram of an optical disc drive provided in an embodiment of the present application;

[0033] FIG4( a ) is a schematic diagram of a blue laser beam 1 and a red laser beam 1 coaxially propagating on a dichroic mirror according to an embodiment of the present application;

[0034] FIG4( b ) is a schematic diagram of a blue laser beam 1 and a red laser beam 1 propagating non-coaxially on a dichroic mirror, provided in an embodiment of the present application;

[0035] FIG4( c ) is a schematic diagram of another blue laser beam 1 and a red laser beam 1 provided in an embodiment of the present application, propagating non-coaxially on a dichroic mirror;

[0036] FIG5 is a schematic diagram showing the deformation of a deformation block of a piezoelectric effect actuator provided in an embodiment of the present application when receiving different electrical signals;

[0037] FIG6 is a schematic diagram of an assembly between a movable component and a dichroic mirror provided in an embodiment of the present application;

[0038] FIG7 is a schematic diagram of an assembly between another movable component and a dichroic mirror provided in an embodiment of the present application;

[0039] FIG8( a ) is a schematic diagram of a blue laser beam 1 and a red laser beam 1 provided in an embodiment of the present application, propagating coaxially with a dichroic mirror in the same orientation;

[0040] FIG8( b ) is a schematic diagram of a blue laser beam 1 and a red laser beam 1 provided in an embodiment of the present application, wherein the dichroic mirror is in the same position and propagates in different axes;

[0041] FIG8( c ) is a schematic diagram of the blue laser beam 1 and the red laser beam 1 provided in an embodiment of the present application propagating in different axes when the dichroic mirror is in another orientation. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0043] The term "and / or" as used herein describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. The symbol " / " as used herein indicates that the related objects are in an "or" relationship, for example, A / B means either A or B.

[0044] The terms "first" and "second" in this specification and claims are used to distinguish different objects rather than to describe a specific order of objects. For example, "first response message" and "second response message" are used to distinguish different response messages rather than to describe a specific order of response messages.

[0045] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0046] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more, for example, multiple processing units means two or more processing units, etc.; multiple elements means two or more elements, etc.

[0047] A single-servo, multi-layer optical disc is a disc structure capable of storing multiple layers of data on a single side. Optical disc drives exploit the transparency between the different data layers of a single-servo, multi-layer disc. By adjusting the laser beam's focus and selecting the appropriate data layer, optical disc drives can read and write data from multiple layers of a single-servo, multi-layer disc. By switching the laser beam's focus or adjusting the laser's wavelength, the optical disc drive allows the read / write head to select a specific data layer for operation.

[0048] Figure 1 is a schematic diagram of the principle of an optical disc drive reading and writing on a single-servo-layer, multi-recording-layer optical disc. As shown in Figure 1, a red laser light, serving as a guide beam, passes through an objective lens and the multiple recording layers of a single-servo-layer, multi-recording-layer optical disc, and is projected onto the guide layer of the single-servo-layer, multi-recording-layer optical disc. The red laser light utilizes the bumps, grooves, or marks of the guide layer to perform servo operations, enabling accurate positioning and tracking of targets in optical devices. A blue laser light, serving as a recording beam, passes through an objective lens and is projected onto a specific recording layer of a single-servo-layer, multi-recording-layer optical disc. The recording beam is focused on the recording layer and interacts with the recording layer to read and write data on the recording layer.

[0049] When an optical drive reads or writes to a single-servo-layer, multi-recording-layer optical disc, the guide beam and the recording beam always remain coaxial. This ensures that the paths of the guide and recording beams in the optical system are aligned, helping to better align and calibrate the beams, ensuring that both beams are precisely focused for optimal optical performance and recording quality. Coaxiality means that the propagation direction of the guide beam matches the propagation direction of the recording beam, and that the center of the guide beam and the center of the recording beam are in the same position. Sharing the same optical path with the recording beam reduces the number of components in the optical system and reduces installation complexity, thereby improving the stability and reliability of the optical system.

[0050] FIG2 is a schematic diagram of the structure of an optical disc drive in the related art. As shown in FIG2 , the red laser light emitted by the red laser diode (RLD) is projected onto the guide layer of the optical disc through various lenses. The blue laser light emitted by the blue laser diode (BLD) is projected onto the recording medium of the optical disc through various lenses and a relay lens group. The optical disc drive can adjust the relay lens group to a set position so that the red laser and the blue laser are coaxial. The coaxial red laser and blue laser can share an actuator to focus and track the objective lens, thereby adjusting the focal depth of the blue laser and operating on different layers of the recording medium.

[0051] In the related art, the coaxiality of the red laser and the blue laser depends on the accuracy of the CD-ROM drive assembly and the accuracy of the components inside the CD-ROM drive. After the CD-ROM drive is assembled, the position of the internal dichroic mirror is fixed and cannot be adjusted. When manufacturers produce CD-ROM drives, it is difficult to ensure that all the red lasers and blue lasers of the CD-ROM drives are coaxial, and errors in different directions will always occur. For errors in the focusing direction, the CD-ROM drive can eliminate the errors in the focusing direction by adjusting the relay lens group. For errors in the tracking direction, the CD-ROM drive can eliminate the errors in the tracking direction by adjusting the objective lens and the actuator. However, the red laser and the blue laser share the same objective lens and actuator. If the CD-ROM drive adjusts the objective lens and the actuator based on the blue laser, the red laser will produce errors in the tracking direction, resulting in the CD-ROM drive being unable to simultaneously eliminate the errors in the tracking directions of the red laser and the blue laser.

[0052] In order to solve the defects of optical disc drives in related technologies, embodiments of the present application provide an optical disc drive, a memory and an electronic device with a single servo layer and multiple recording layers. Typically, a dichroic prism or dichroic mirror is present inside the optical disc drive. The red laser can directly pass through the dichroic mirror and be transmitted to the recording medium of the optical disc. The blue laser is projected onto the side surface of the dichroic mirror and is reflected to the recording medium of the optical disc. The dichroic mirror can be fixed inside the optical disc drive by a movable component, such as inside the optical head of the optical disc drive. The movable component can change the orientation of the dichroic mirror to adjust the relative position between the propagation direction of the red laser and the propagation direction of the blue laser, so that the red laser and the blue laser always remain coaxial, thereby eliminating errors generated during the installation and use of the optical disc drive.

[0053] FIG3 is a schematic diagram of the structure of an optical disc drive provided in an embodiment of the present application. As shown in FIG3 , the optical disc drive 300 may include a first light source 301, a second light source 302, a dichroic mirror 303, a movable assembly 304, an anamorphic prism 305, a polarizing beam splitter (PBS) 306, a PBS 307, a photodetector 308, a photodetector 309, a focus servo circuit 310, a tracking servo circuit 311, a focus servo circuit 312, a tracking servo circuit 313, a beam splitter diode aperture 313, a quarter-wave plate 314, and an objective lens 315.

[0054] In an embodiment of the present application, the wavelength of the light source emitted by the first light source 301 is different from the wavelength of the light source emitted by the second light source 302. One of the first light source 301 and the second light source 302 serves as a recording light source. The recording light beam generated by the recording light source can be focused on the recording layer and interact with the recording layer to realize reading and writing data on the recording layer. The other light source between the first light source 301 and the second light source 302 serves as a guiding light source. The guiding light beam generated by the guiding light source is focused and tracked on the servo layer, which can realize the function of accurately positioning and tracking the target in the optical device. In an embodiment of the present application, the first light source 301 serves as a recording light source and can emit a blue laser. The second light source 302 serves as a guiding light source and can emit a red laser.

[0055] The blue laser light can be projected onto one side of the dichroic mirror 303 through optical devices such as the anamorphic prism 305, PBS 306, and a convex mirror. The anamorphic prism 305 is a specially designed optical device used to change the aspect ratio of the input light beam, thereby deforming or compressing the light beam to the desired deformation effect. In the embodiment of the present application, after the blue laser light passes through the anamorphic prism 305, the light in the optical path is deformed or compressed, thereby deforming or compressing the blue laser light to the desired deformation effect, thereby meeting the requirements for writing data on the optical disc recording medium.

[0056] A PBS is an optical device typically composed of special optical materials and a reflective coating. The PBS can split an input light beam into two mutually perpendicular beams of equal intensity according to a set polarization direction. In the embodiment of the present application, PBS 306 can split a blue laser into two mutually perpendicular blue laser sub-beams of equal intensity, projecting one blue laser sub-beam 1 onto a surface on one side of the dichroic mirror 303 and the other blue laser sub-beam 2 onto the light inlet of a photodetector 308.

[0057] A photodetector is a device that converts light energy into an electrical signal, used to detect and measure light intensity. In this embodiment, after receiving the blue laser sub-beam 2, the photodetector 308 converts the blue laser sub-beam 2 into an electrical signal of a corresponding value to detect the intensity of the blue laser sub-beam 2. After the photodetector 308 detects the intensity of the blue laser sub-beam 2, it can adjust the position and direction of the optical path based on the intensity signal.

[0058] The photodetector 308 can be connected to a focus servo circuit 310 and a tracking servo circuit 311. The photodetector 308 can generate a control signal based on the light intensity signal of the blue laser sub-beam 2 and send it to the focus servo circuit 310 and the tracking servo circuit 311 to control the movement of the optical device and adjust the phase position and relative direction of the blue laser sub-beam 1 projected onto the optical disc. In the embodiment of the present application, the light inlet of the photodetector generally has four quadrants, each of which is equipped with a photosensitive detector. If the blue laser sub-beam 2 has focus deviation and tracking deviation when it is input to the input port of the photodetector 308, the light intensity received by the four quadrants of the photodetector 308 will be different. The photodetector 308 can detect the focus deviation and tracking deviation of the blue laser sub-beam 2 by performing different addition and subtraction operations on the light intensities of the four quadrants. The photodetector 308 can convert the focus deviation signal into an electrical signal of corresponding value and send it to the focus servo circuit 310, and convert the tracking deviation signal into an electrical signal of corresponding value and send it to the tracking servo circuit 311.

[0059] The focus servo circuit 310 can adjust the focal position of the optical path by controlling the positions of optical components (e.g., objective lens 315, dichroic aperture 313, quarter-wave plate 314, etc.). In the embodiment of the present application, the focus servo circuit 310 can be connected to the objective lens 315. After receiving the electrical signal corresponding to the focus deviation signal from the photodetector 308, the focus servo circuit 310 can cause the servo system to make minute displacement adjustments to the objective lens 315 based on changes in the electrical signal corresponding to the focus deviation signal from the photodetector 308, so as to achieve the optimal focus position for the blue laser sub-beam 1.

[0060] The tracking servo circuit 311 can track the position of the light source or the moving target by controlling the direction of optical devices (such as the objective lens 315, the beam splitter diode aperture 313, the quarter wave plate 314, etc.). In the embodiment of the present application, the tracking servo circuit 311 can be connected to the objective lens 315. After receiving the electrical signal corresponding to the tracking deviation signal of the photodetector 308, the tracking servo circuit 311 can adjust the direction of the objective lens 315 according to the change of the electrical signal corresponding to the tracking deviation signal of the photodetector 308, so that the objective lens 315 accurately follows the position change of the blue laser sub-beam 1, so that the objective lens 315 can maintain the correct pointing direction of the blue laser sub-beam 1.

[0061] The red laser light can pass through optical devices such as the PBS 307 and a convex mirror and be projected onto the dichroic mirror 303. The PBS 307 splits the red laser light into two mutually perpendicular red laser sub-beams of equal intensity. One red laser sub-beam 1 is projected onto the dichroic mirror 303, while the other red laser sub-beam 2 is projected onto the light inlet of the photodetector 309. After receiving the red laser sub-beam 2, the photodetector 309 converts the red laser sub-beam 2 into an electrical signal corresponding to the value to detect the intensity of the red laser sub-beam 2. After detecting the intensity of the red laser sub-beam 2, the photodetector 309 can adjust the direction of the optical path based on the intensity signal.

[0062] The photodetector 309 can be electrically connected to the focus servo circuit 312 and the tracking servo circuit 313. The photodetector 309 can detect the intensity signal of the red laser sub-beam 2 based on the intensity of the red laser sub-beam 2 projected into the four quadrants and generate a control signal. The photodetector 309 sends the control signal to the focus servo circuit 312 and the tracking servo circuit 313 to control the movement of the optical components and adjust the phase position and relative direction of the red laser sub-beam 1 projected onto the optical disc.

[0063] In the embodiment of the present application, the focus servo circuit 312 can be connected to the objective lens 315. After receiving the electrical signal corresponding to the focus deviation signal from the photodetector 309, the focus servo circuit 312 can cause the servo system to make minute displacement adjustments to the objective lens 315 based on changes in the electrical signal corresponding to the focus deviation signal from the photodetector 309, so that the focus of the red laser sub-beam 1 can reach the optimal position.

[0064] After receiving the electrical signal corresponding to the tracking deviation signal from the photodetector 309, the tracking servo circuit 313 can allow the servo system to adjust the direction of the objective lens 315 according to the change of the electrical signal corresponding to the tracking deviation signal from the photodetector 309, so that the objective lens 315 can accurately follow the position change of the red laser sub-beam 1, thereby enabling the objective lens 315 to maintain the correct pointing direction of the red laser sub-beam 1.

[0065] The dichroic mirror 303 is an optical device, also known as a polarizing filter or birefringent filter. The dichroic mirror 303 utilizes the birefringence of the material to selectively transmit or block light in a specific direction through different refractive indices (or refractive indices). In other words, the dichroic mirror 303 is an optical device that allows light beams of a set wavelength to pass through and light beams of other wavelengths to reflect. In the embodiment of the present application, the dichroic mirror 303 allows red laser light with a longer wavelength to pass through and reflects blue laser light with a shorter wavelength. In other words, after the red laser light is projected onto the surface of the dichroic mirror 303, it will pass directly through the dichroic mirror 303. After the blue laser light is projected onto the surface of the dichroic mirror 303, it will be reflected, changing the direction of the blue laser light. The propagation direction of the red laser light projected by the dichroic mirror 303 is coaxial with the propagation direction of the reflected blue laser light, and is projected onto the optical disc through optical devices such as the beam splitter diode aperture 313, the quarter-wave plate 314, and the objective lens 315.

[0066] A beam splitter aperture is an optical device typically composed of a series of color-separating filters and an aperture. The filters in the beam splitter aperture have specific optical properties, allowing only light within a specific wavelength range to pass through while reflecting or absorbing light at other wavelengths, which is controlled by the aperture. In this embodiment, coaxial red and blue lasers pass through the beam splitter aperture 313, separating the different wavelength components in the incident beam to improve the purity of both lasers.

[0067] A quarter-wave plate is an optical device used to change the polarization state of an incident light beam. Made of a special material, the quarter-wave plate has a thickness approximately one-quarter the wavelength of the light. In the embodiment of the present application, after the coaxial red and blue lasers pass through the quarter-wave plate 314, the quarter-wave plate 314 can convert linear polarization in one direction into circular polarization in the other, or convert circular polarization in one direction into linear polarization, thereby adjusting and changing the polarization state of the coaxial red and blue lasers.

[0068] An objective lens is an optical device used to focus and project light. In the embodiment of the present application, after the coaxial red and blue lasers pass through objective lens 315, objective lens 315 accurately focuses the coaxial red and blue lasers onto the data track on the optical disc surface, ensuring accurate reading or writing of data. Through functions such as focusing, tracking, and spot shape control, objective lens 315 provides precise and stable optical performance for the optical disc drive.

[0069] Dichroic mirror 303 is movably positioned at a location where the propagation directions of the red laser beam 1 intersect with the propagation directions of the blue laser beam 1. In this embodiment of the present application, the propagation direction of the red laser beam 1 is perpendicular to the plane of the optical disc. When dichroic mirror 303 is positioned between the second light source 302 and the optical disc, the propagation direction of the red laser beam 1 does not change with changes in the position and angle of dichroic mirror 303.

[0070] When the propagation direction of the blue laser beam 1 differs from the propagation direction of the red laser beam 1, the blue laser beam 1 is projected onto the surface of the dichroic mirror 303 and is reflected therefrom, changing the propagation direction of the blue laser beam 1. After reflection, the propagation direction of the blue laser beam 1 is coaxial with the propagation direction of the red laser beam 1.

[0071] In one possible embodiment, as shown in Figure 4(a), the propagation direction of the blue laser beam 1 is perpendicular to the propagation direction of the red laser beam 1. The angle between the surface of the dichroic mirror 303 and the propagation direction of the red laser beam 1 is 45°. After the blue laser beam 1 is projected onto the surface of the dichroic mirror 303, it is reflected from the surface of the dichroic mirror 303. The propagation direction of the reflected blue laser beam 1 is consistent with the propagation direction of the transmitted red laser beam 1, achieving the effect of coaxiality between the two beams.

[0072] It should be noted that the propagation direction of the reflected blue laser beam 1 in Figure 4(a) is not coaxial with the propagation direction of the transmitted red laser beam 1. This is to make it easier for readers to distinguish the two beams. In essence, the propagation direction of the reflected blue laser beam 1 and the propagation direction of the transmitted red laser beam 1 coincide.

[0073] As shown in FIG4(b), when the angle between the propagation directions of the blue laser beam 1 and the red laser beam 1 is greater than 90°, after the blue laser beam 1 is projected onto the surface of the dichroic mirror 303, the propagation direction of the reflected blue laser beam 1 is inconsistent with the propagation direction of the transmitted red laser beam 1. The propagation direction of the reflected blue laser beam 1 is below the propagation direction of the transmitted red laser beam 1.

[0074] To ensure that the propagation direction of the reflected blue laser beam 1 is coaxial with the propagation direction of the transmitted red laser beam 1, the orientation of the dichroic mirror 303 can be adjusted to change the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1. This adjusts the relative position between the propagation direction of the reflected blue laser beam 1 and the propagation direction of the transmitted red laser beam 1, thereby maintaining the coaxial propagation direction of the reflected blue laser beam 1 with the propagation direction of the transmitted red laser beam 1. In this embodiment of the present application, the dichroic mirror 303 can be slightly tilted forward within the optical disc drive 300 to change the angle between its surface and the propagation direction of the blue laser beam 1, so that the blue laser beam 1 is incident on the surface of the dichroic mirror 303 at a 45° angle. This reduction in the reflection angle of the blue laser beam 1 allows the propagation direction of the reflected blue laser beam 1 to be coaxial with the propagation direction of the transmitted red laser beam 1.

[0075] As shown in FIG4(c), when the angle between the propagation directions of the blue laser beam 1 and the red laser beam 1 is less than 90°, after the blue laser beam 1 is projected onto the surface of the dichroic mirror 303, the propagation direction of the reflected blue laser beam 1 is inconsistent with the propagation direction of the transmitted red laser beam 1. The propagation direction of the reflected blue laser beam 1 is above the propagation direction of the transmitted red laser beam 1.

[0076] To ensure that the propagation direction of the reflected blue laser beam 1 is coaxial with the propagation direction of the transmitted red laser beam 1, the orientation of the dichroic mirror 303 can be adjusted to change the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1. This adjusts the relative position between the propagation direction of the reflected blue laser beam 1 and the propagation direction of the transmitted red laser beam 1, thereby achieving coaxiality between the propagation direction of the reflected blue laser beam 1 and the propagation direction of the transmitted red laser beam 1. In this embodiment of the present application, the dichroic mirror 303 can be slightly tilted backward within the optical disc drive 300 to change the angle between its surface and the propagation direction of the blue laser beam 1, so that the blue laser beam 1 is incident on the surface of the dichroic mirror 303 at a 45° angle. This increase in the reflection angle of the blue laser beam 1 allows the propagation direction of the reflected blue laser beam 1 to be coaxial with the propagation direction of the transmitted red laser beam 1.

[0077] Movable assembly 304 movably secures dichroic mirror 303 within optical disc drive 300. Movable assembly 304 secures the position of dichroic mirror 303, preventing it from moving within optical disc drive 300 and potentially affecting product reliability. Movable assembly 304 can adjust the orientation of dichroic mirror 303 to adjust the relative position between the propagation direction of reflected blue laser beam 1 and the propagation direction of transmitted red laser beam 1, ensuring that the propagation directions of reflected blue laser beam 1 and transmitted red laser beam 1 remain coaxial.

[0078] Active component 304 may be a piezoelectric actuator. A piezoelectric actuator is a device that uses the piezoelectric effect to control or drive a device. The piezoelectric effect refers to the change in charge distribution in certain crystals or ceramic materials when subjected to pressure, thereby generating an electric field or potential difference. Piezoelectric actuators utilize the piezoelectric effect to control or drive a device by applying pressure or pressure.

[0079] As shown in FIG5 , the piezoelectric effect driver may include a deformation block. The deformation block may be lead barium zirconate titanate (PZT). The two ends of the deformation block are electrically connected to the positive and negative poles of the power supply, respectively. When the power supply does not apply an electrical signal to the two ends of the deformation block, the deformation block does not deform. When the power supply applies an electrical signal to the two ends of the deformation block, the deformation block will deform and become a deformation block with a larger radius and a smaller axial length. Among them, within a reasonable range, the greater the electrical signal applied by the power supply, the greater the deformation of the deformation block. That is, the larger the radius of the deformation block, the shorter the axial length.

[0080] FIG6 is a schematic diagram of an assembly between a movable assembly and a dichroic mirror provided in an embodiment of the present application. As shown in FIG6 , movable assembly 304 includes four piezoelectric effect actuators. One end of the four piezoelectric effect actuators is respectively fixed to the four corners of the dichroic mirror 303 frame. The other ends of the four piezoelectric effect actuators are respectively fixed to the inner surface of the housing of the optical disc drive 300 or the surface of other devices. The four piezoelectric effect actuators are electrically connected to the controller independently. The controller can apply electrical signals of different sizes to the four piezoelectric effect actuators to achieve arbitrary changes in the orientation of the dichroic mirror 303. Optionally, the number of piezoelectric effect actuators included in movable assembly 304 is not limited to the four shown in FIG6 , but can also be other numbers. The position where the piezoelectric effect actuator is installed is not limited to the position shown in FIG6 , but can also be other positions.

[0081] For example, when the dichroic mirror 303 needs to be tilted to the left (left as shown in FIG6 ) by a certain angle, the controller applies an electrical signal of the same magnitude to the upper left piezoelectric effect actuator and the lower left piezoelectric effect actuator, and does not need to apply an electrical signal to the upper right piezoelectric effect actuator and the lower right piezoelectric effect actuator. Alternatively, the controller applies an electrical signal of the same magnitude to the upper left piezoelectric effect actuator and the lower left piezoelectric effect actuator, but a larger electrical signal than the electrical signal of the same magnitude applied to the upper right piezoelectric effect actuator and the lower right piezoelectric effect actuator.

[0082] For another example, when dichroic mirror 303 needs to tilt to the lower left by a certain angle, the controller applies an electrical signal to the piezoelectric effect actuator on the lower left, and does not need to apply electrical signals to the piezoelectric effect actuator on the upper left, upper right, and lower right. Alternatively, the controller applies electrical signals of the same magnitude to the piezoelectric effect actuator on the upper left and lower right, but with a smaller magnitude than the electrical signal applied to the piezoelectric effect actuator on the lower left. Alternatively, the controller applies an electrical signal to the piezoelectric effect actuator on the upper right, but with a smaller magnitude than the electrical signal applied to the piezoelectric effect actuator on the upper left and lower right.

[0083] FIG7 is a schematic diagram of the assembly between another movable assembly and a dichroic mirror provided in an embodiment of the present application. As shown in FIG7 , the dichroic mirror 303 includes a frame. The frame is composed of two frame structures. One side of the two frame structures is separated from each other, and the opposite side is connected together. The dichroic mirror 303 is embedded within one frame structure. The movable assembly 304 includes two piezoelectric effect actuators. The two piezoelectric effect actuators are respectively arranged at opposite ends of one side of the two frame structures that are separated from each other and fixed to the sides of the two frame structures that are close to each other. The two piezoelectric effect actuators are independently electrically connected to a controller. The controller can apply electrical signals of different magnitudes to the two piezoelectric effect actuators to arbitrarily change the orientation of the dichroic mirror 303. Optionally, the number of piezoelectric effect actuators included in the movable assembly 304 is not limited to the two shown in FIG7 , but can also be any other number. The locations where the piezoelectric effect actuators are installed are not limited to the locations shown in FIG7 , but can also be other locations.

[0084] Normally, the two piezoelectric actuators are positioned between one side of the two frame structures, pushing the two frame structures apart. When the axial length of the piezoelectric actuators decreases, the two frame structures, under the action of the restoring force, move one side of the two frame structures closer together.

[0085] As shown in FIG8( a ), after one side of the frame of the dichroic mirror 303 is fixed to a set position inside the optical disc drive 300, the two frame structures of the frame are in a normal state. That is, one side of the two frame structures is spread apart from each other. After the red laser beam 1 is projected onto the dichroic mirror 303, it is directly transmitted from the dichroic mirror 303, and the propagation direction remains unchanged. After the blue laser beam 1 is projected onto the surface of the dichroic mirror 303, it is reflected on the surface of the dichroic mirror 303, changing its propagation direction. At this time, the propagation direction of the reflected blue laser beam 1 is consistent with the propagation direction of the transmitted red laser beam 1, achieving the effect of the two beams being coaxial.

[0086] As shown in FIG8( b ), when the propagation direction of the blue laser beam 1 changes, after the blue laser beam 1 is projected onto the surface of the dichroic mirror 303, the propagation direction of the reflected blue laser beam 1 is inconsistent with the propagation direction of the transmitted red laser beam 1. The propagation direction of the reflected blue laser beam 1 is to the left of the propagation direction of the transmitted red laser beam 1.

[0087] To ensure that the propagation direction of the reflected blue laser beam 1 is coaxial with the propagation direction of the transmitted red laser beam 1, the orientation of the dichroic mirror 303 can be adjusted to change the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1. This adjusts the relative position between the propagation direction of the reflected blue laser beam 1 and the propagation direction of the transmitted red laser beam 1, thereby ensuring that the propagation direction of the reflected blue laser beam 1 remains coaxial with the propagation direction of the transmitted red laser beam 1. In this embodiment of the present application, the controller can reduce the electrical signal applied to the piezoelectric effect actuator between the two frame structures. When the electrical signal at both ends of the piezoelectric effect actuator is reduced, the axial length increases, increasing the distance between the two frame structures' side edges. Under the action of the restoring force of the piezoelectric effect actuator, the frame structure of the two frame structures on which the dichroic mirror 303 is mounted moves slightly upward to reduce the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1. After the reflection angle of the blue laser sub-beam 1 is increased, the propagation direction of the reflected blue laser sub-beam 1 is coaxial with the propagation direction of the transmitted red laser sub-beam 1 .

[0088] As shown in FIG8(c), when the propagation direction of the blue laser beam 1 changes, after the blue laser beam 1 is projected onto the surface of the dichroic mirror 303, the propagation direction of the reflected blue laser beam 1 is inconsistent with the propagation direction of the transmitted red laser beam 1. The propagation direction of the reflected blue laser beam 1 is to the right of the propagation direction of the transmitted red laser beam 1.

[0089] To ensure that the propagation direction of the reflected blue laser beam 1 is coaxial with the propagation direction of the transmitted red laser beam 1, the orientation of the dichroic mirror 303 can be adjusted to change the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1. This adjusts the relative position between the propagation direction of the reflected blue laser beam 1 and the propagation direction of the transmitted red laser beam 1, thereby maintaining the coaxial propagation direction of the reflected blue laser beam 1 with the propagation direction of the transmitted red laser beam 1. In this embodiment of the present application, the controller can increase the electrical signal applied to the piezoelectric effect actuator between the two frame structures. When the electrical signal at both ends of the piezoelectric effect actuator increases, the axial length decreases, reducing the distance between the two frame structures' side edges. Under the action of the restoring force, the two frame structures move slightly downward to increase the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1. The reduction in the reflection angle of the blue laser beam 1 allows the propagation direction of the reflected blue laser beam 1 to be coaxial with the propagation direction of the transmitted red laser beam 1.

[0090] In the embodiments of the present application, the electrical signal applied by the controller to the piezoelectric effect actuator is related to the degree to which the spot of blue laser beam 1 deviates from the recorded data track. This relationship can be studied and determined through experimentation. Generally speaking, the greater the degree to which the spot of blue laser beam 1 deviates from the recorded data track, the greater the electrical signal applied by the controller to the piezoelectric effect actuator. The smaller the degree to which the spot of blue laser beam 1 deviates from the recorded data track, the smaller the electrical signal applied by the controller to the piezoelectric effect actuator.

[0091] The controller can use a push-pull method to detect deviations of the blue laser beam 1 spot from the recorded data track. The basic principle of the push-pull method is to apply an alternating voltage to a piezoelectric material, causing it to vibrate mechanically. This vibration causes slight changes in the light propagation path, resulting in deviation of the spot. The degree of deviation can be controlled by adjusting the frequency and amplitude of the applied voltage. After the controller determines that the blue laser beam 1 spot has deviated from the center of the data track, the four-quadrant photodetector detects the degree of deviation. A low-pass filter removes high-frequency responses and noise from the outputs of the four-quadrant photodetector. The low-frequency component of the output represents the fixed deviation between the propagation directions of the blue and red laser beams. The controller converts this fixed deviation into an electrical signal of a corresponding value and inputs it into the piezoelectric effect driver, which adjusts the position of the dichroic mirror 303 to ensure that the propagation directions of the blue and red laser beams 1 remain coaxial.

[0092] In an embodiment of the present application, a dichroic mirror 303 is utilized to transmit and reflect laser beams of different wavelengths. The dichroic mirror 303 can be designed to be movably fixed within the optical disc drive 300. The light beam generated by the second light source 302 can be directly transmitted through the dichroic mirror 303, and its propagation direction does not change with changes in the orientation of the dichroic mirror 303. The light beam generated by the first light source 301 is reflected upon the surface of the dichroic mirror 303. The reflected light beam changes its propagation direction with changes in the orientation of the dichroic mirror 303. When the propagation direction of the light beam from the first light source 301 projected onto the optical disc is not coaxial with the propagation direction of the light beam from the second light source 302 projected onto the optical disc, the orientation of the dichroic mirror 303 can be changed to adjust the relative position between the propagation directions of the light beams from the first light source 301 and the second light source 302, thereby ensuring that the propagation directions of the light beams from the first light source 301 and the second light source 302 remain coaxial. The optical disc drive 300 protected by this application has the advantages of small internal structure changes, simple implementation process, and high control accuracy. When the light beam of the second light source 302 is accurately served in the servo layer at a relatively low cost, the light beam of the first light source 301 is projected to the center of the data track of each recording layer of the optical disc.

[0093] An embodiment of the present application provides a memory, which includes an optical disc drive and an optical disc, and the optical disc drive can read and write data from the optical disc. The optical disc drive can be a single-servo layer multi-recording layer optical disc drive as shown in Figures 3 to 8(c). The optical disc can be an optical disc or other type of single-servo layer multi-recording layer optical disc. Since the memory includes the optical disc drive, the memory has all or at least some of the advantages of the optical disc drive. The memory can be a CD, DVD, BD, etc. The memory can be a dedicated optical disc type, such as an optical disc image file, an optical disc mirror file, etc. The memory can be a storage medium based on optical technology, such as an optical memory and an optical disc array.

[0094] The number and types of components in the memory provided by the embodiments of this application are not limited to the above-described embodiments. Any technical solution implemented under the principles of this application is within the scope of protection of this solution. Any technical solution combining one or more embodiments or illustrations in the specification in an appropriate manner is within the scope of protection of this solution.

[0095] An embodiment of the present application provides an electronic device comprising at least one memory. The memory comprises an optical disc drive as shown in Figures 3 to 8(c). Because the electronic device comprises the optical disc drive, the electronic device has all or at least some of the advantages of the optical disc drive. The electronic device may be a desktop computer, a server, a portable notebook computer, or the like.

[0096] The number and types of components in the electronic devices provided by the embodiments of this application are not limited to the above-described embodiments. Any technical solution implemented under the principles of this application is within the scope of protection of this solution. Any technical solution that is combined in an appropriate manner with one or more embodiments or illustrations in the specification is within the scope of protection of this solution.

[0097] Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present application. Those skilled in the art should understand that, although the present application has been described in detail with reference to the aforementioned embodiments, the technical solutions described in the aforementioned embodiments may be modified or some of the technical features thereof may be replaced with equivalents. However, such modifications or replacements do not deviate from the spirit and scope of the technical solutions in the various embodiments of the present application.

Claims

1. A single-servo-layer multi-recording-layer optical disc drive, characterized in that: include: A first light source (301) is used to generate a first light beam to read and write data on the recording layer; A second light source (302) is used to generate a second light beam for performing focusing and tracking servo on the servo layer; the propagation direction of the second light beam intersects with the propagation direction of the first light beam; A dichroic mirror (303) is arranged at a position where the propagation direction of the second light beam intersects with the propagation direction of the first light beam, and is used to reflect the first light beam and transmit the second light beam; A movable component (304) movably fixes the dichroic mirror inside the optical disc drive and is used to change the orientation of the dichroic mirror to adjust the relative position between the propagation direction of the first light beam and the propagation direction of the second light beam.

2. The optical disc drive according to claim 1, wherein: The movable assembly includes at least one piezoelectric effect actuator, one end of the at least one piezoelectric effect actuator is respectively fixed to different positions of the dichroic mirror, and the other end of the at least one piezoelectric effect actuator is respectively fixed to different positions inside the optical disc drive; The at least one piezoelectric effect actuator is respectively used to change the orientation of the dichroic mirror when receiving an electrical signal.

3. The optical disc drive according to claim 1, wherein: The dichroic mirror comprises a frame, and the frame comprises two frame structures, one side of the two frame structures is separated from each other, and the opposite side is connected together; one side of the two frame structures connected to each other is fixed inside the optical disc drive; The movable component includes at least one piezoelectric effect driver, which is arranged between two mutually separated sides of the two frame structures and is used to change the orientation of the dichroic mirror when receiving an electrical signal.

4. The optical disc drive according to claim 2 or 3, characterized in that: Also includes: The controller is connected to the piezoelectric effect driver respectively, and is used to detect the deviation value between the light spot of the first light beam and the light spot of the second light beam, and send an electrical signal of a corresponding value to the piezoelectric effect driver.

5. The optical disc drive according to any one of claims 1 to 4, characterized in that: Also includes: The first photodetector (308) is used to receive the first light beam and convert a focusing deviation signal and / or a tracking deviation signal of the first light beam into an electrical signal of a corresponding value.

6. The optical disc drive according to claim 5, characterized in that: Also includes: a first focus servo circuit (310) and a first tracking servo circuit (311), The first focus servo circuit is used to adjust the focus position of the first light beam according to the change of the electrical signal corresponding to the focus deviation signal of the first photodetector; The first tracking servo circuit is used to adjust the direction of the first light beam according to the change of the electrical signal corresponding to the tracking deviation signal of the first photodetector.

7. The optical disc drive according to claim 5 or 6, characterized in that: Also includes: The first polarization beam splitter (306) is arranged at a position in the propagation direction of the first light beam, and is used to split the first light beam into two identical sub-beams, and project one sub-beam to the light inlet of the first photodetector, and project the other sub-beam to the dichroic mirror.

8. The optical disc drive according to any one of claims 1 to 7, characterized in that: Also includes: The second photodetector (309) is used to receive the second light beam and convert a focusing deviation signal and / or a tracking deviation signal of the second light beam into an electrical signal of a corresponding value.

9. The optical disc drive according to claim 8, characterized in that: Also includes: a second focus servo circuit (312) and a second tracking servo circuit (313), The second focus servo circuit is used to adjust the focus position of the second light beam according to the change of the electrical signal corresponding to the focus deviation signal of the second photodetector; The second tracking servo circuit is used to adjust the direction of the second light beam according to the change of the electrical signal corresponding to the tracking deviation signal of the second photodetector.

10. The optical disc drive according to claim 8 or 9, characterized in that: Also includes: The second polarization beam splitter (307) is arranged at a position in the propagation direction of the second light beam, and is used to split the second light beam into two identical sub-beams, and project one sub-beam to the light inlet of the second photodetector, and project the other sub-beam to the dichroic mirror.

11. A memory, characterized in that: include: At least one single servo layer multi-recording layer optical disc, At least one optical disc drive as claimed in any one of claims 1 to 10, used to read and write data on the at least one single-servo-layer multi-recording-layer optical disc.

12. An electronic device, characterized in that: include: at least one memory as claimed in claim 11, At least one controller is respectively connected to the at least one memory and is used to control the at least one memory to read and write data.

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