A single-servo-layer, multi-recording-layer optical disc drive, memory, and electronic device.

Abstract

A single-servo-layer, multi-recording-layer optical disc drive, memory, and electronic device are disclosed. The optical disc drive contains a dichroic mirror. A beam of light from a first light source is projected onto one surface of the dichroic mirror and reflected onto the recording medium of the optical disc for reading and writing data. A beam of light from a second light source can directly pass through the dichroic mirror and be transmitted onto the servo layer of the recording medium. The dichroic mirror can be fixed inside the optical disc drive by a movable component. The movable component can change the orientation of the dichroic mirror to adjust the relative position between the propagation directions of the beams from the first and second light sources, eliminating errors generated during installation and use of the optical disc drive. The optical disc drive of this application has advantages such as minimal changes to the internal structure, simple implementation, and high control precision, achieving precise servoing of the second light source beam on the servo layer while the beam of the first light source is projected onto the center of the data track of each recording layer of the optical disc at a relatively low cost.

Description

Technical Field

[0001] This invention relates to the field of optical disc technology, and more particularly to a single-servo-layer, multi-recording-layer optical disc drive, memory, and electronic device. Background Technology

[0002] An optical disc drive is a device used to read and write optical discs. Optical disc drives are typically optional components of 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). The working principle of an optical disc drive is to use a laser beam to read and write to the surface of the disc. When the optical disc drive reads a disc, the light reflected from the laser beam is detected by a sensor and then converted into a digital signal to extract the data on the disc. Simultaneously, the optical disc drive can also write data to the disc by adjusting the intensity and focus of the laser beam.

[0003] In related technologies, optical disc drives use a red laser to servo a pre-pressed single-layer guide layer and a coaxial blue laser to record data across multiple recording layers when writing data to a single-servo, multi-layer disc. During installation and use, the light source directions of the red and blue lasers may change, potentially causing them to become misaligned and affecting the quality of data writing and reading. Summary of the Invention

[0004] To address the aforementioned problems, this application provides a single-servo-layer, multi-recording-layer optical disc drive, in which an internal dichroic mirror is movably fixed within the drive to adjust the relative position between the guide beam and the recording beam, thus eliminating errors generated during installation and use. Furthermore, this application also provides a memory and electronic device corresponding to this single-servo-layer, multi-recording-layer optical disc drive.

[0005] Therefore, the following technical solutions are adopted in the embodiments of this application:

[0006] In a first aspect, embodiments of this application provide 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 focusing and track-following servoing 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 disposed at the 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; and 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 directions of the first light beam and the second light beam.

[0007] In this embodiment, a dichroic mirror is used to transmit and reflect laser light of different wavelengths. 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 its propagation direction does not change with the orientation of the dichroic mirror. 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 with the orientation of the dichroic mirror. When the propagation direction of the light beam from the first light source onto the optical disc is not coaxial with the propagation direction of the light beam from the second light source onto the optical disc, the orientation of the dichroic mirror can be changed by altering the movable components to adjust the propagation direction of the light beam from the first light source onto the optical disc. The optical disc drive has advantages such as minimal changes to its internal structure, simple implementation, and high control precision. It achieves precise servoing of the second light source's light beam on the servo layer while the light beam from the first light source is projected onto the center of the data tracks of each recording layer of the optical disc at a relatively low cost.

[0008] In one embodiment, the active component includes at least one piezoelectric actuator, one end of which is fixed to different positions of the dichroic mirror, and the other end of which is fixed to different positions inside the optical disc drive; the at least one piezoelectric actuator is used to change the orientation of the dichroic mirror when receiving an electrical signal.

[0009] In this embodiment, the piezoelectric actuator is a very common device with advantages such as low price, convenient control, and precise control. After the dichroic mirror is fixed inside the optical disc drive by the piezoelectric actuator, if the orientation of the dichroic mirror is changed, it is only necessary to change the electrical signal flowing into each piezoelectric actuator to change the orientation of the dichroic mirror. The whole process is very simple and the control cost is relatively low.

[0010] In one embodiment, the dichroic mirror includes a frame, the frame including two frame structures, one side of the two frame structures being separated from each other, and the opposite side being connected together; the connected side of the two frame structures is fixed inside the optical disc drive; the movable component includes at least one piezoelectric effect driver disposed between the separated sides of the two frame structures, for changing the orientation of the dichroic mirror when receiving an electrical signal.

[0011] In this embodiment, if the frame of the dichroic mirror comprises two frame structures, with one side of each frame structure separated from the other and the opposite side connected together, a piezoelectric actuator can be positioned between the separated sides. To change the orientation of the dichroic mirror, only the electrical signals flowing into each piezoelectric actuator need to be changed, making the entire process simpler and reducing control costs.

[0012] In one embodiment, the system further includes a controller connected to a piezoelectric effect driver, configured to detect the degree of deviation between the spot of the first beam and the spot of the second beam, and send an electrical signal with a corresponding value to the piezoelectric effect driver.

[0013] In this embodiment, the controller is the central unit for precisely controlling the orientation of the dichroic mirror. It can change the electrical signals flowing into each piezoelectric effect driver according to the deviation between the light spots of the first beam and the second beam, thereby precisely changing the orientation of the dichroic mirror to adjust the relative position between the first beam and the second beam. This ensures that when the servo layer accurately completes servo control, the first beam used for reading and writing by the recording layer always remains in the center of the data track, eliminating the deviation caused by different coaxiality due to different driver installation errors.

[0014] In one embodiment, it further includes: a first photodetector, configured to receive the first light beam and convert the focusing deviation signal and / or tracking deviation signal of the first light beam into an electrical signal of corresponding value.

[0015] In this embodiment, after receiving the first light beam, the first photodetector converts the light beam into a corresponding electrical signal to detect the light intensity of the first light beam. The photodetector's inlet typically has four quadrants, each equipped with a photosensitive detector. If there are focusing or tracking deviations, the light intensities received by the photodetector in each of the four quadrants will be different. The photodetector detects these focusing and tracking errors by performing addition and subtraction operations on the different light intensities in the four quadrants.

[0016] In one embodiment, the system further 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 beam according to the change in the electrical signal corresponding to the focus deviation signal of the first photodetector; and the first tracking servo circuit is used to adjust the direction of the first beam according to the change in the electrical signal corresponding to the track deviation signal of the first photodetector.

[0017] In this embodiment, the first focal servo circuit can make minute displacement adjustments to the objective lens based on changes in the light intensity signal of the first beam, so that the focal point of the first beam can reach the optimal position. The first tracking servo circuit can adjust the direction of the objective lens based on changes in the light intensity signal of the first beam, so that the objective lens accurately follows the positional changes of the first beam, enabling the objective lens to maintain the correct direction of the first beam.

[0018] In one embodiment, the device further includes: a first polarizing beam splitter, positioned in the propagation direction of the first beam, for splitting the first beam into two identical sub-beams, projecting one sub-beam onto the light inlet of the first photodetector, and projecting the other sub-beam onto the dichroic mirror.

[0019] In this embodiment, the first polarization beam splitter can split the first beam into two sub-beams of equal intensity so that the first polarization beam splitter can detect the intensity of the first beam on the projection recording medium.

[0020] In one embodiment, it further includes: a second photodetector for receiving the second light beam and converting the focusing deviation signal and / or tracking deviation signal of the second light beam into an electrical signal with corresponding values.

[0021] In this embodiment, after receiving the second light beam, the second photodetector converts the second light beam into a corresponding electrical signal to detect the light intensity of the second light beam. If there is a focusing or tracking deviation, the light intensity received by the photodetector in each of the four quadrants will be different. The photodetector detects the focusing and tracking errors by performing addition and subtraction operations on the different light intensities in the four quadrants.

[0022] In one embodiment, the system further 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 beam according to the change in 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 beam according to the change in the electrical signal corresponding to the track deviation signal of the second photodetector.

[0023] In this embodiment, the second focus servo circuit can make minute displacement adjustments to the objective lens based on changes in the light intensity signal of the second beam, so that the focus of the second beam can reach the optimal position. The second tracking servo circuit can adjust the direction of the objective lens based on changes in the light intensity signal of the second beam, so that the objective lens accurately follows the positional changes of the second beam, enabling the objective lens to maintain the correct direction of the second beam.

[0024] In one embodiment, it further includes: a second polarization beam splitter, disposed at a position in the propagation direction of the second beam, for splitting the second beam into two identical sub-beams, projecting one sub-beam onto the light inlet of the second photodetector, and projecting the other sub-beam onto the dichroic mirror.

[0025] Secondly, embodiments of this application provide 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.

[0026] Thirdly, embodiments of this application provide an electronic device, including: at least one memory as may be implemented in the various embodiments of the second aspect, and at least one controller connected to the at least one memory for controlling the at least one memory to read and write data. Attached Figure Description

[0027] The accompanying drawings used in the description of the embodiments or prior art are briefly introduced below.

[0028] Figure 1 A schematic diagram illustrating the principle of optical disc drive reading and writing on a single-servo-layer, multi-recording-layer optical disc;

[0029] Figure 2 This is a schematic diagram of the structure of an optical disc drive in related technologies;

[0030] Figure 3 This is a schematic diagram of the structure of an optical disc drive provided in an embodiment of this application;

[0031] Figure 4(a) is a schematic diagram of the blue laser beam 1 and the red laser beam 1 propagating coaxially on a dichroic mirror in the embodiment of this application;

[0032] Figure 4(b) is a schematic diagram of the non-axial propagation of a blue laser beam 1 and a red laser beam 1 on a dichroic mirror provided in an embodiment of this application;

[0033] Figure 4(c) is a schematic diagram of another blue laser beam 1 and a red laser beam 1 propagating on the dichroic mirror in an embodiment of this application.

[0034] Figure 5 This is a schematic diagram of the deformation of the piezoelectric effect actuator provided in this embodiment of the application, which receives different electrical signals and generates deformation.

[0035] Figure 6 This is a schematic diagram illustrating the assembly between an active component and a dichroic mirror provided in an embodiment of this application;

[0036] Figure 7 This is a schematic diagram illustrating the assembly between another active component and a dichroic mirror provided in an embodiment of this application;

[0037] Figure 8(a) is a schematic diagram of the blue laser beam 1 and the red laser beam 1 provided in the embodiment of this application propagating coaxially in the same orientation of the dichroic mirror;

[0038] Figure 8(b) is a schematic diagram of the blue laser beam 1 and the red laser beam 1 provided in the embodiment of this application propagating on different axes when the dichroic mirror is in the same position;

[0039] Figure 8(c) is a schematic diagram of the blue laser beam 1 and the red laser beam 1 provided in the embodiment of this application propagating on different axes when the dichroic mirror is in another position. Detailed Implementation

[0040] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0041] In this article, the term "and / or" describes 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. The symbol " / " in this article indicates that the related objects are in an "or" relationship; for example, A / B means A or B.

[0042] The terms "first" and "second," etc., used in the specification and claims herein are used to distinguish different objects, not to describe a specific order of objects. For example, "first response message" and "second response message," etc., are used to distinguish different response messages, not to describe a specific order of response messages.

[0043] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0044] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0045] A single-servo-layer, multi-recording-layer optical disc (SCD) is an optical disc structure with multi-layer data storage capability on one side. Optical disc drives utilize the transparency between different data layers of a SCD; by adjusting the focus of the laser beam and selecting appropriate data layers, they can read and write to multiple data layers of the SCD. The optical disc drive allows the read / write head to select specific data layers for operation by switching the focus position of the laser beam or adjusting the laser wavelength.

[0046] Figure 1 This is a schematic diagram illustrating the principle of an optical disc drive reading and writing to a single-servo, multi-recording-layer optical disc. (Example:) Figure 1 As shown, a red laser, serving as a guide beam, passes through an objective lens and multiple recording layers of a single-servo-layer, multi-recording-layer optical disc, and is projected onto the guide layer. The red laser utilizes the bumps, grooves, or markings on the guide layer for servo operation, enabling precise positioning and target tracking in optical devices. A blue laser, serving as a recording beam, passes through the objective lens and is projected onto a specific recording layer of the single-servo-layer, multi-recording-layer optical disc. The recording beam is focused on the recording layer and interacts with it, enabling the reading and writing of data on the recording layer.

[0047] When an optical disc drive reads and writes to a single-servo, multi-recording-layer disc, the guide beam and recording beam must always remain coaxial, and their paths within the optical system must be aligned. This helps to better align and calibrate the beams, ensuring that both beams are precisely focused at the focal point for optimal optical performance and recording quality. Coaxiality means that the propagation direction of the guide beam is the same as that of the recording beam, and the centers of the guide and recording beams are located at the same position. Sharing an optical path with the recording beam reduces the number of components and installation complexity of the optical system, thereby improving its stability and reliability.

[0048] Figure 2 This is a schematic diagram of the structure of an optical disc drive in related technologies. For example... Figure 2As shown, the red laser emitted by the red laser diode (RLD) is projected onto the guide layer of the optical disc through various lenses. The blue laser emitted by the blue laser diode (BLD) is projected onto the recording medium of the optical disc through various lenses and a relay lens assembly. The optical disc drive can adjust the relay lens assembly to a set position, making the red and blue lasers coaxial. The coaxial red and blue lasers can share a single focusing and tracking control of the objective lens by an actuator, thereby adjusting the depth of focus of the blue laser and operating on different layers of the recording medium.

[0049] In related technologies, the coaxiality of the red and blue lasers relies on the assembly precision of the optical disc drive and the precision of its internal components. After assembly, the position of the internal dichroic mirror is fixed and cannot be adjusted. When manufacturing optical disc drives, it's difficult for manufacturers to ensure that the red and blue lasers are coaxial in all drives; errors in different directions will always occur. For errors in the focusing direction, the optical disc drive can eliminate them by adjusting the relay lens group. For errors in the tracking direction, the optical disc drive can eliminate them by adjusting the objective lens and actuator. However, the red and blue lasers share the objective lens and actuator. If the optical disc drive adjusts the objective lens and actuator based on the blue laser, the red laser will generate errors in the tracking direction, preventing the optical disc drive from simultaneously eliminating the tracking errors of both the red and blue lasers.

[0050] To address the shortcomings of existing optical disc drives in related technologies, this application provides a single-servo-layer, multi-recording-layer optical disc drive, memory, and electronic device. Typically, an optical disc drive contains a dichroic mirror. Red laser light can pass directly through the dichroic mirror and onto the recording medium of the optical disc. Blue laser light, after being projected onto one surface of the dichroic mirror, is reflected onto the recording medium. 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 directions of the red and blue lasers, ensuring that the red and blue lasers remain coaxial and eliminating errors generated during the installation and use of the optical disc drive.

[0051] Figure 3 This is a schematic diagram of the structure of an optical disc drive provided in an embodiment of this application. Figure 3As shown, the optical disc drive 300 may include a first light source 301, a second light source 302, a dichroic mirror 303, a moving component 304, a deformable 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 aperture 313, a quarter-wave plate 314, and an objective lens 315.

[0052] In this embodiment, the wavelength of the light emitted by the first light source 301 is different from the wavelength of the light 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 beam generated by the recording light source can be focused on the recording layer and interact with the recording layer to read and write data on the recording layer. The other light source of the first light source 301 and the second light source 302 serves as a guiding light source. The guiding beam generated by the guiding light source is focused and tracked in the servo layer, enabling accurate positioning and target tracking in optical devices. In this embodiment, the first light source 301, as a recording light source, can emit blue laser light. The second light source 302, as a guiding light source, can emit red laser light.

[0053] Blue laser light can pass through optical devices such as deformable prism 305, PBS 306, and convex mirrors, and be projected onto one side of the surface of dichroic mirror 303. The deformable prism 305 is a specially designed optical device used to change the aspect ratio of the input beam, achieving the desired deformation or compression of the beam. In this embodiment, after the blue laser light passes through the deformable prism 305, the light in the optical path is deformed or compressed, achieving the desired deformation effect to meet the requirements of writing data on the optical disc recording medium.

[0054] A photodiode beam splitter (PBS) is an optical device typically composed of special optical materials and a reflective coating. A PBS can split an input light beam into two mutually perpendicular beams of equal intensity according to a set polarization direction. In this embodiment, the 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 the surface of one side of a dichroic mirror 303, and projecting the other blue laser sub-beam 2 onto the light inlet of a photodetector 308.

[0055] A photodetector is a device that converts light energy into an electrical signal for detecting and measuring 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 light intensity of the blue laser sub-beam 2. After detecting the light intensity of the blue laser sub-beam 2, the photodetector 308 can adjust the position and direction of the optical path according to the light intensity signal.

[0056] The photodetector 308 can be connected to the focus servo circuit 310 and the tracking servo circuit 311. The photodetector 308 can generate control signals based on the intensity signal of the blue laser sub-beam 2, and send them to the focus servo circuit 310 and the tracking servo circuit 311 to control the movement of the optical components, thereby adjusting the phase position and relative direction of the blue laser sub-beam 1 projected onto the optical disc. In this embodiment, the photodetector's inlet generally has four quadrants, each equipped with a photosensitive detector. If there is a focus deviation and a tracking deviation when the blue laser sub-beam 2 enters 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 addition and subtraction operations on the different light intensities of the four quadrants. The photodetector 308 can convert the focus deviation signal into a corresponding electrical signal and send it to the focus servo circuit 310, and convert the tracking deviation signal into a corresponding electrical signal and send it to the tracking servo circuit 311.

[0057] The focus servo circuit 310 can adjust the focal position of the optical path by controlling the positions of optical components (such as the objective lens 315, the aperture of the beam splitter 313, the quarter wave plate 314, etc.). In this embodiment, the focus servo circuit 310 can be connected to the objective lens 315. After receiving the electrical signal corresponding to the focus deviation signal of the photodetector 308, the focus servo circuit 310 can adjust the objective lens 315 slightly according to the change of the electrical signal corresponding to the focus deviation signal of the photodetector 308, so that the focus of the blue laser sub-beam 1 can reach the optimal position.

[0058] The tracking servo circuit 311 can track the position of a light source or a moving target by controlling the orientation of optical components (such as the objective lens 315, the aperture of the beam splitter 313, the quarter-wave plate 314, etc.). In this embodiment, the tracking servo circuit 311 can be connected to the objective lens 315. After receiving the electrical signal corresponding to the tracking deviation signal from the photodetector 308, the tracking servo circuit 311 can adjust the orientation of the objective lens 315 according to the change in the electrical signal corresponding to the tracking deviation signal from the photodetector 308, so that the objective lens 315 accurately follows the position change of the blue laser sub-beam 1, and the objective lens 315 can maintain the correct orientation of the blue laser sub-beam 1.

[0059] Red laser light can pass through optical devices such as a PBS 307 and a convex mirror, and be projected onto a 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, and the other red laser sub-beam 2 is projected onto the light inlet of a photodetector 309. After receiving the red laser sub-beam 2, the photodetector 309 converts the red laser sub-beam 2 into a corresponding electrical signal to detect its intensity. 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.

[0060] The photodetector 309 is 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 projected into the four quadrants based on the light intensity, and generate control signals. The photodetector 309 sends the control signals to the focus servo circuit 312 and the tracking servo circuit 313 to control the movement of the optical components, thereby adjusting the phase position and relative direction of the red laser sub-beam 1 projected onto the optical disc.

[0061] In this embodiment, the focus servo circuit 312 can be connected to the objective lens 315. After receiving the electrical signal corresponding to the focus deviation signal of the photodetector 309, the focus servo circuit 312 can adjust the objective lens 315 slightly according to the change of the electrical signal corresponding to the focus deviation signal of the photodetector 309, so that the focus of the red laser sub-beam 1 can reach the optimal position.

[0062] After receiving the electrical signal corresponding to the tracking deviation signal from the photodetector 309, the tracking servo circuit 313 can 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, and the objective lens 315 can maintain the correct direction of the red laser sub-beam 1.

[0063] A dichroic mirror 303 is an optical device, also known as a polarizing filter or birefringent filter. Utilizing the birefringence of materials, the dichroic mirror 303 selectively transmits or blocks light from specific directions through different refractive indices (or refractive indexes). In other words, the dichroic mirror 303 is an optical device that allows light beams of a set wavelength to pass through while reflecting light beams of other wavelengths. In this embodiment, the dichroic mirror 303 allows longer-wavelength red laser light to pass through and shorter-wavelength blue laser light to be reflected. That is, when red laser light is projected onto the surface of the dichroic mirror 303, it passes directly through the dichroic mirror 303. When blue laser light is projected onto the surface of the dichroic mirror 303, it is 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 the light is projected onto an optical disc through optical devices such as the beam splitter aperture 313, the quarter-wave plate 314, and the objective lens 315.

[0064] A beam splitter aperture is an optical device, typically composed of a series of color-separating filters and an aperture. The filters in a beam splitter aperture have specific optical characteristics, allowing only light within a specific wavelength range to pass through, while reflecting or absorbing light of other wavelengths, and this is controlled by the aperture. In this embodiment, coaxial red and blue lasers pass through the beam splitter aperture 313, separating different wavelength components in the incident beam to improve the purity of the two lasers.

[0065] A quarter-wave plate is an optical device used to change the polarization state of an incident light beam. A quarter-wave plate is a waveplate made of a special material, with a thickness approximately one-quarter of the wavelength of light. In this embodiment, after coaxial red and blue lasers pass through the quarter-wave plate 314, the quarter-wave plate 314 can convert linearly polarized light in one direction into circularly polarized light in another direction, or convert circularly polarized light in one direction into linearly polarized light, thereby adjusting and changing the polarization state of the coaxial red and blue lasers.

[0066] An objective lens is an optical device used to focus and project light. In this embodiment, after the coaxial red and blue lasers pass through the objective lens 315, the objective lens 315 accurately focuses the coaxial red and blue lasers onto the data track on the surface of the optical disc, maintaining accurate reading or writing of data. The objective lens 315 provides precise and stable optical performance for the optical disc drive through functions such as focusing, tracking, and spot shape control.

[0067] The dichroic mirror 303 is movably disposed at the position where the propagation direction of the red laser beam 1 intersects with the propagation direction of the blue laser beam 1. In this embodiment, the propagation direction of the red laser beam 1 is perpendicular to the plane of the optical disc. When the dichroic mirror 303 is disposed between the second light source 302 and the optical disc, the propagation direction of the red laser beam 1 will not change with the position and angle of the dichroic mirror 303.

[0068] When the propagation direction of the blue laser beam 1 is not the same as that of the red laser beam 1, 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 300, changing the propagation direction of the blue laser beam 1. The propagation direction of the reflected blue laser beam 1 is then coaxial with that of the red laser beam 1.

[0069] 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 will be 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 of the two beams.

[0070] It should be noted that the propagation direction of the reflected blue laser beam 1 and the propagation direction of the transmitted red laser beam 1 in Figure 4(a) are not shown coaxially, but this is to facilitate the reader in distinguishing between 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 are coincident.

[0071] As shown in Figure 4(b), when the angle between the propagation direction of the blue laser beam 1 and the propagation direction of 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.

[0072] To ensure that the propagation direction of the reflected blue laser beam 1 is coaxial with that of the transmitted red laser beam 1, the orientation of the dichroic mirror 303 can be adjusted. This changes the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1, thereby adjusting the relative position between them and maintaining coaxiality. In this embodiment, the dichroic mirror 303 can be slightly tilted forward inside the optical disc drive 300, changing the angle between its surface and the propagation direction of the blue laser beam 1, so that the angle between the blue laser beam 1 incident on the surface of the dichroic mirror 303 is 45°. Reducing the reflection angle of the blue laser beam 1 ensures that the propagation direction of the reflected blue laser beam 1 is coaxial with that of the transmitted red laser beam 1.

[0073] As shown in Figure 4(c), when the angle between the propagation direction of the blue laser beam 1 and the propagation direction of 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.

[0074] To ensure that the propagation direction of the reflected blue laser beam 1 is coaxial with that of the transmitted red laser beam 1, the orientation of the dichroic mirror 303 can be adjusted. This changes the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1, thereby adjusting the relative position between them and achieving coaxiality. In this embodiment, the dichroic mirror 303 can be slightly tilted back inside the optical disc drive 300 to change the angle between its surface and the propagation direction of the blue laser beam 1, making the angle at which the blue laser beam 1 incident on the surface of the dichroic mirror 303 45°. Increasing the reflection angle of the blue laser beam 1 further ensures that the propagation direction of the reflected blue laser beam 1 is coaxial with that of the transmitted red laser beam 1.

[0075] The movable component 304 movably fixes the dichroic mirror 303 inside the optical disc drive 300. The movable component 304 can fix the position of the dichroic mirror 303, preventing it from moving inside the optical disc drive 300 and affecting product reliability. The movable component 304 can change the orientation of the dichroic mirror 303 to adjust 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, ensuring that the propagation directions of the reflected blue laser beam 1 and the transmitted red laser beam 1 remain coaxial.

[0076] The active component 304 can 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 crystalline or ceramic materials when subjected to pressure or force, thereby generating an electric field or potential difference. Piezoelectric actuators utilize the piezoelectric effect to control or drive corresponding devices by applying pressure or force.

[0077] like Figure 5 As shown, a piezoelectric actuator may include a deformation block. The deformation block may be barium lead zirconate titanate (PZT). The two ends of the deformation block are electrically connected to the positive and negative terminals of a power supply, respectively. When no electrical signal is applied to the two ends of the deformation block, the deformation block does not deform. When an electrical signal is applied to the two ends of the deformation block, the deformation block will deform, becoming a deformation block with a larger radius and a smaller axial length. Within a reasonable range, the larger 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 its axial length.

[0078] Figure 6 This is a schematic diagram illustrating the assembly of an active component and a dichroic mirror as provided in an embodiment of this application. Figure 6 As shown, the active component 304 includes four piezoelectric actuators. One end of each of the four piezoelectric actuators is fixed to one of the four corners of the frame of the dichroic mirror 303. The other ends of each of the four piezoelectric actuators are fixed to the inner surface of the housing of the optical disc drive 300 or the surface of another device. Each of the four piezoelectric actuators is independently electrically connected to a controller. The controller can apply electrical signals of different magnitudes to the four piezoelectric actuators to arbitrarily change the orientation of the dichroic mirror 303. Optionally, the number of piezoelectric actuators included in the active component 304 is not limited to... Figure 6 The four shown can be replaced with other numbers. The mounting location of the piezoelectric actuator is not limited to... Figure 6 The location shown can also be other locations.

[0079] For example, dichroic mirror 303 needs to be tilted to the left (with... Figure 6When the left side (as shown in the image) is tilted at a certain angle, the controller applies the same electrical signal to the piezoelectric effect drivers at the upper left and lower left, but does not need to apply an electrical signal to the piezoelectric effect drivers at the upper right and lower right. Alternatively, the controller applies an equal electrical signal to the piezoelectric effect drivers at the upper left and lower left that is greater than the same electrical signal applied to the piezoelectric effect drivers at the upper right and lower right.

[0080] For example, when the dichroic mirror 303 needs to tilt to the lower left at a certain angle, the controller applies an electrical signal to the piezoelectric effect driver at the lower left, and does not need to apply electrical signals to the piezoelectric effect drivers at the upper left, upper right, and lower right. Alternatively, the controller applies the same magnitude of electrical signal to the piezoelectric effect drivers at the upper left and lower right, but less than the electrical signal applied to the piezoelectric effect driver at the lower left. Alternatively, the controller applies an electrical signal to the piezoelectric effect driver at the upper right, but less than the electrical signals applied to the piezoelectric effect drivers at the upper left and lower right.

[0081] Figure 7 This is a schematic diagram illustrating the assembly of another active component and a dichroic mirror provided in an embodiment of this application. Figure 7 As shown, 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 inside one of the frame structures. The movable component 304 includes two piezoelectric effect actuators. The two piezoelectric effect actuators are respectively disposed at both ends of the separated side of the two frame structures and fixed to the adjacent side of the two frame structures. The two piezoelectric effect actuators are independently electrically connected to the 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 component 304 is not limited to... Figure 7 The two shown can be replaced with other numbers. The mounting location of the piezoelectric actuator is not limited to... Figure 7 The location shown can also be other locations.

[0082] Normally, two piezoelectric actuators are positioned between one side of two frame structures, keeping one side of the two frame structures apart. When the axial length of the piezoelectric actuators decreases, the two frame structures move closer together under the action of restoring force, with one side of the two frame structures moving closer together.

[0083] As shown in Figure 8(a), after one side of the frame of the dichroic mirror 303 is fixed to a predetermined 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 mutually supported. After the red laser beam 1 is projected onto the dichroic mirror 303, it is directly transmitted through 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 will be reflected on the surface of the dichroic mirror 303, changing the 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 coaxiality of the two beams.

[0084] As shown in Figure 8(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 not the same as 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.

[0085] To ensure that the propagation direction of the reflected blue laser beam 1 is coaxial with that of the transmitted red laser beam 1, the orientation of the dichroic mirror 303 can be adjusted. This changes the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1, thereby adjusting the relative position between them and maintaining coaxiality. In this embodiment, the controller can reduce the electrical signal applied to the piezoelectric actuator between the two frame structures. Reducing the electrical signal at both ends of the piezoelectric actuator increases the axial length, increasing the distance that separates one side of the two frame structures. Under the restoring force of the piezoelectric actuator, the frame structure with the dichroic mirror 303 installed moves slightly upward, reducing 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 beam 1 is increased, the propagation direction of the reflected blue laser beam 1 is made to be coaxial with the propagation direction of the transmitted red laser beam 1.

[0086] As shown in Figure 8(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 not the same as 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.

[0087] To ensure that the propagation direction of the reflected blue laser beam 1 is coaxial with that of the transmitted red laser beam 1, the orientation of the dichroic mirror 303 can be adjusted. This changes the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1, thereby adjusting the relative position between them and maintaining coaxiality. In this embodiment, the controller can increase the electrical signal applied to the piezoelectric effect actuator between the two frame structures. Increased electrical signals at both ends of the piezoelectric effect actuator shorten the axial length, reducing the distance between one side of the two frame structures. Under the action of restoring force, the two frame structures move slightly downwards, increasing the angle between the surface of the dichroic mirror 303 and the propagation direction of the blue laser beam 1. The reduced reflection angle of the blue laser beam 1 ensures that the propagation direction of the reflected blue laser beam 1 is coaxial with that of the transmitted red laser beam 1.

[0088] In this embodiment, the electrical signal applied by the controller to the piezoelectric effect driver is related to the degree to which the spot of the blue laser beam splitter 1 deviates from the recorded data trajectory. This relationship can be studied and determined experimentally. Generally, the greater the degree to which the spot of the blue laser beam splitter 1 deviates from the recorded data trajectory, the larger the electrical signal applied by the controller to the piezoelectric effect driver. Conversely, the smaller the degree to which the spot of the blue laser beam splitter 1 deviates from the recorded data trajectory, the smaller the electrical signal applied by the controller to the piezoelectric effect driver.

[0089] The controller can use a push-pull method to detect the deviation of the blue laser beam 1 from the recorded data trajectory. 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 can lead to a slight change in the light propagation path, thus causing the beam spot to deviate. By adjusting the frequency and amplitude of the applied voltage, the degree of beam spot deviation can be controlled. After the controller determines that the blue laser beam 1's beam spot has deviated from the center of the data trajectory, the four-quadrant photodetector will detect the degree of deviation. A low-pass filter filters out high-frequency responses and noise from the outputs of the four quadrant photodetectors, leaving the low-frequency component as the fixed deviation between the propagation directions of the blue and red laser beams. The controller converts this fixed deviation into a corresponding electrical signal, which is then input to the piezoelectric effect driver to adjust the orientation of the dichroic mirror 303, ensuring that the propagation directions of the blue and red laser beams remain coaxial.

[0090] In this embodiment, a dichroic mirror 303 is used to transmit and reflect laser light of different wavelengths. The dichroic mirror 303 can be designed to be movably fixed inside 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 will not change with the orientation of the dichroic mirror 303. The light beam generated by the first light source 301 is reflected after being projected onto the surface of the dichroic mirror 303. The reflected light beam changes its propagation direction with 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, so as to keep the propagation directions of the light beams from the first light source 301 and the second light source 302 coaxial. The optical disc drive 300 protected by this application has the advantages of minimal changes to its internal structure, simple implementation process, and high control precision. It achieves precise servoing of the beam of the second light source 302 on the servo layer at a lower cost, while the beam of the first light source 301 is projected onto the center of the data track of each recording layer of the optical disc.

[0091] This application provides a memory including an optical disc drive and an optical disc, wherein the optical disc drive can read and write data on the optical disc. The optical disc drive can be, for example,... Figures 3 to 8(c) The diagram shows a single-servo-layer, multi-recording-layer optical disc drive. The optical disc can be a CD or other type of single-servo-layer, multi-recording-layer optical disc. Because the memory includes this optical disc drive, it possesses all or at least some of the advantages of that 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 image file, etc. The memory can be an optical technology-based storage medium, such as optical memory and optical disc arrays.

[0092] The number and types of components in the memory provided in this application are not limited to the above embodiments. All technical solutions implemented under the principles of this application are within the protection scope of this solution. Any one or more embodiments or figures in the specification, combined in a suitable manner, are within the protection scope of this solution.

[0093] This application provides an electronic device including at least one memory. The memory includes, for example, […]. Figures 3 to 8(c) The optical disc drive shown is an example. Because the electronic device includes this optical disc drive, it possesses all or at least some of the advantages of that optical disc drive. The electronic device can be a desktop computer, server, laptop computer, etc.

[0094] The number and types of components in the electronic devices provided in this application are not limited to the above embodiments. All technical solutions implemented under the principles of this application are within the protection scope of this solution. Any one or more embodiments or figures in the specification, combined in a suitable manner, are within the protection scope of this solution.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application. Those skilled in the art should understand that although this application has been described in detail with reference to the foregoing embodiments, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions in the embodiments of this 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 for reading and writing data on the recording layer; A second light source (302) is used to generate a second beam for focusing and tracking servoing in the servo layer; the propagation direction of the second beam intersects with the propagation direction of the first beam. A dichroic mirror (303) is disposed at a position where the propagation direction of the second beam intersects with the propagation direction of the first beam, and is used to reflect the first beam and transmit the second beam. The active component (304) movably fixes the dichroic mirror inside the optical disc drive to change the orientation of the dichroic mirror, thereby adjusting the relative position between the propagation direction of the first beam and the propagation direction of the second beam.

2. The optical disc drive according to claim 1, characterized in that, The active component includes at least one piezoelectric actuator, one end of which is fixed to different positions of the dichroic mirror, and the other end of which is fixed to different positions inside the optical disc drive. The at least one piezoelectric effect driver is used to change the orientation of the dichroic mirror when an electrical signal is received.

3. The optical disc drive according to claim 1, characterized in that, 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 connected side of the two frame structures is fixed inside the optical disc drive. The active component includes at least one piezoelectric actuator disposed between two separate sides of the two frame structures, for changing the orientation of the dichroic mirror upon 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 and is used to detect the degree of deviation between the light spot of the first beam and the light spot of the second beam, and send an electrical signal with the corresponding value to the piezoelectric effect driver.

5. The optical disc drive according to any one of claims 1-3, characterized in that, Also includes: A first photodetector (308) is used to receive the first beam and convert the focus deviation signal and / or track tracking deviation signal of the first beam into an electrical signal with corresponding values.

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

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

8. The optical disc drive according to any one of claims 1-3, characterized in that, Also includes: The second photodetector (309) is used to receive the second beam and convert the focus deviation signal and / or track deviation signal of the second beam into an electrical signal with corresponding values.

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

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

11. A memory, characterized in that, include: At least one single-servo multi-recording-layer optical disc, At least one optical disc drive as described in any one of claims 1-10, for reading and writing 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 described in claim 11, At least one controller is connected to each of the at least one of the aforementioned memories and is used to control the at least one of the aforementioned memories to read and write data.

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