Torquer equipment of coaxial holographic storage system

Abstract

The utility model discloses torquer equipment of a coaxial holographic storage system, which comprises an objective lens, a first supporting plate, a first supporting seat, a focusing moving device, a reflecting mirror and a tracking moving device, the objective lens is arranged on the first supporting plate, the first supporting plate is arranged on the first supporting seat through the focusing moving device, and the reflecting mirror is arranged on the first supporting seat through the tracking moving device. The focusing moving device is used for enabling the first supporting plate and the objective lens to move in the focusing direction, the reflector is arranged on the first supporting seat, and the first supporting seat is arranged on the tracking moving device. The tracking moving device is used for enabling the first supporting seat, the reflector and the objective lens to move in the tracking direction, wherein the focusing direction is perpendicular to the tracking direction. Compared with a direct movement holographic optical disc and a motor for driving the holographic optical disc to rotate, focusing and tracking are realized by moving the objective lens and the reflector which are relatively light in weight, and the precision is easy to control.

Description

Technical Field

[0001] The utility model relates to the technical field of coaxial holographic storage, in particular to a torquer device of a coaxial holographic storage system. Background Art

[0002] With the rapid development of IoT and artificial intelligence, the amount of data generated in our daily lives is exploding. According to International Data Corporation (IDC), the world will generate 159.2 zettabytes (ZB) of data by 2024, and this figure is expected to more than double to 384.6 ZB by 2028. A large portion of this massive amount of data is rarely accessed, cold data. Therefore, the development of low-energy, long-life, and high-capacity cold data storage technology is becoming increasingly urgent. Traditional optical storage technology, due to its low cost, low energy consumption, and long storage life, holds a significant position in the cold data storage field. The recent emergence of holographic storage technology effectively addresses the limited capacity and slow read speed issues of traditional optical storage.

[0003] The coaxial holographic storage system is an advanced three-dimensional data storage solution that records data through the interaction of a laser beam and a hologram. In a coaxial holographic storage system, the objective lens typically remains in a fixed position, while precise focusing is achieved by adjusting the holographic disc. However, since the holographic disc must be rotated by a motor, its overall weight is relatively large, which poses certain challenges when performing high-speed, high-precision movement. Utility Model Content

[0004] Therefore, it is necessary to provide a torquer device for a coaxial holographic storage system to solve the problem that the holographic disc needs to be driven by a motor to rotate and its overall weight is large, which leads to certain challenges when moving.

[0005] To achieve the above-mentioned purpose, this embodiment provides a torquer device of a coaxial holographic storage system, including an objective lens, a first support plate, a first support seat, a focusing movement device, a reflector and a tracking movement device, wherein the objective lens is arranged on the first support plate, the first support plate is arranged on the first support seat through the focusing movement device, the focusing movement device is used to move the first support plate and the objective lens along a focusing direction, the reflector is arranged on the first support seat, the first support seat is arranged on the tracking movement device, and the tracking movement device is used to move the first support seat, the reflector and the objective lens along a tracking direction, wherein the focusing direction is perpendicular to the tracking direction.

[0006] Furthermore, it also includes a second support seat, and the tracking movement device includes two tracking movement units, and the tracking movement unit includes a permanent magnet, a tracking coil and a tracking suspension wire. The permanent magnet is arranged on the second support seat, and the permanent magnet is located on one side of the tracking coil. The tracking coil is arranged on the first support seat, and the tracking suspension wire is arranged on the first support seat and the second support seat. The tracking suspension wire has an elastic part with a bending part, wherein the tracking coil generates a magnetic field when energized, and interacts with the magnetic field where the permanent magnet is located to generate an electromagnetic force in the tracking direction, which is combined with the elastic force of the tracking suspension wire to make the tracking coil move along the tracking direction.

[0007] Furthermore, the focusing moving device includes two focusing moving units, and the two focusing moving units are located on both sides of the objective lens. The focusing moving units include a focusing coil and a focusing suspension. The two focusing moving units share one focusing coil, and the focusing coil is located on the inner side of the tracking coil. The focusing coil is arranged on the first support plate, and the first support plate is arranged on the first support seat through the focusing suspension. The focusing suspension is curved and elastic, wherein the focusing coil generates a magnetic field when energized, and interacts with the magnetic field where the permanent magnet is located to generate an electromagnetic force in the focusing direction, which is combined with the elastic force of the focusing suspension to make the focusing coil move along the focusing direction.

[0008] Furthermore, the focusing movement unit also includes a first connecting block, the focusing suspension is connected to the first connecting block, and the first connecting block is plugged into the first support plate so that the focusing suspension is arranged on the first support seat through the first connecting block. The focusing suspension and the first connecting block are conductors, and the focusing suspension / the tracking suspension, the first connecting block, and the focusing coil / the tracking coil are electrically connected through wires.

[0009] Furthermore, it also includes a yoke, which is a U-shaped structure. The permanent magnet, the tracking coil, and the focusing coil are all located inside the yoke, and the permanent magnet is plugged into the yoke.

[0010] Furthermore, the focusing suspension line extends along the tracking direction, the tracking suspension line is perpendicular to the focusing suspension line, and the extending direction is perpendicular to the focusing direction, and the focusing suspension line and the tracking suspension line are staggered up and down.

[0011] Furthermore, the tracking coil has a curved portion that avoids the focusing coil.

[0012] Furthermore, the tracking movement unit has two tracking suspension wires, an upper tracking suspension wire and a lower tracking suspension wire, and a cross-sectional area of ​​the upper tracking suspension wire is different from a cross-sectional area of ​​the lower tracking suspension wire.

[0013] Furthermore, the tracking moving unit also includes a second connecting block, the tracking suspension wire is connected to the second connecting block, and the second connecting block is plugged into the first support seat so that the tracking suspension wire is arranged on the first support seat through the second connecting block. The tracking suspension wire and the second connecting block are conductors, and the tracking suspension wire, the second connecting block, and the tracking coil are electrically connected through wires.

[0014] Furthermore, the focusing moving device includes two focusing moving units, and the two focusing moving units are located on both sides of the objective lens. The focusing moving units include a focusing coil and a focusing suspension wire. The two focusing moving units share one focusing coil. The focusing coil is arranged on the first support plate and is located on one side of the permanent magnet. The first support plate is arranged on the first support seat through the focusing suspension wire. The focusing suspension wire is curved and elastic. When the focusing coil is energized, a magnetic field is generated, which interacts with the magnetic field where the permanent magnet is located to generate an electromagnetic force in the focusing direction, so that the focusing coil moves along the focusing direction.

[0015] The above technical solution has the following beneficial effects:

[0016] Compared to directly moving the holographic disc and the motor that drives its rotation, this application achieves focusing and tracking by moving a lightweight objective lens and reflector, making it easier to operate and control precision. Furthermore, the synchronized tracking of the objective lens and reflector allows the incident light to maintain a consistent angle of incidence during tracking servo, meeting the requirement for consistent angles of incidence for both read and write light in coaxial holographic storage systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a three-dimensional diagram of the torquer device in this embodiment;

[0018] Figure 2 is a three-dimensional diagram of the objective lens, the first support plate and the focus moving unit in this embodiment;

[0019] Figure 3 is a three-dimensional diagram of the yoke, permanent magnet, and tracking coil in this embodiment;

[0020] Figure 4 This is a front perspective view of the focusing movement device and the tracking movement device in this embodiment;

[0021] Figure 5 This is a rear perspective view of the focusing movement device and the tracking movement device in this embodiment;

[0022] Figure 6 Schematic diagram of the structure of the coaxial holographic storage system in this embodiment;

[0023] Figure 7is a schematic diagram of the astigmatism error signal FE in this embodiment;

[0024] Figure 8 is a schematic diagram showing an S-curve value of the focus error signal FE in this embodiment;

[0025] Figure 9 This is a schematic diagram of determining the direction and distance of the focus spot offset from the optical disc track according to the push-pull method in this embodiment.

[0026] Description of reference numerals:

[0027] 1. objective lens; 11. first support plate;

[0028] 2. Focus moving device; 21. Focus moving unit; 211. Focus coil; 212. Focus suspension wire; 2121. First upper focus suspension wire; 2122. Second upper focus suspension wire; 2123. First lower focus suspension wire; 2124. Second lower focus suspension wire; 213. First connecting block; 214. Copper rivet 1; 215. Wire 2; 216. Wire 4;

[0029] 3. Reflector; 31. Second support plate;

[0030] 4. Tracking device; 41. Tracking unit; 411. Tracking coil; 4111. Second tracking coil; 4112. Fourth tracking coil; 412. Tracking suspension wire; 4121. First upper tracking suspension wire; 4122. Second upper tracking suspension wire; 4123. First lower tracking suspension wire; 4124. Second lower tracking suspension wire; 413. Second connecting block; 414. Permanent magnet; 415. Third connecting block; 416. Wire one; 417. Wire three; 418. Wire five; 419. Wire six;

[0031] 5. First support seat; 51. Limiting column 1; 52. Limiting column 2;

[0032] 6. Second support seat;

[0033] 7. Yoke; 71. Groove;

[0034] 8. Semiconductor laser;

[0035] 9. Polarization beam splitter;

[0036] 100. Collimating lens;

[0037] 110. Dichroic beam splitter;

[0038] 120, 1 / 4 wave plate;

[0039] 130. Four-quadrant detector;

[0040] 140. Holographic optical disc; 1401. Substrate; 1402. Color separation reflective layer; 1403. Holographic medium layer; 1404. Protective layer; 1405. Address information pit; 1406. Pre-groove;

[0041] 150, motor;

[0042] 160, first ray;

[0043] 170. Second ray. DETAILED DESCRIPTION

[0044] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of this application, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0045] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0046] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0047] In the description of this application, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0048] In this application, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, priority or sequence relationship between these entities or operations.

[0049] Without further limitations, in this application, the words "include", "comprise", "have" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those defined elements, but also other elements not explicitly listed, or elements inherent to such process, method or product.

[0050] Consistent with the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceed" are understood to exclude the number itself; expressions such as "above," "below," and "within" are understood to include the number itself. Furthermore, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this manner, such as "multiple groups," "multiple times," etc., unless otherwise specifically defined.

[0051] In the description of the embodiments of the present application, the space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present application.

[0052] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "installed", "connected", "connected", "fixed", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the present application, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0053] See also Figures 1 to 5This embodiment provides a torquer device of a coaxial holographic storage system, including an objective lens 1, a first support plate 11, a focusing movement device 2, a reflector 3 and a tracking movement device 4. The objective lens 1 is arranged on the first support plate 11, and the first support plate 11 is arranged on the first support seat 5 through the focusing movement device 2. The focusing movement device 2 is used to move the first support plate 11 and the objective lens 1 along the focusing direction. The reflector 3 is arranged on the first support seat 5, and the first support seat 5 is arranged on the tracking movement device 4. The tracking movement device 4 is used to move the first support seat 5, the reflector 3 and the objective lens 1 along the tracking direction, wherein the focusing direction is perpendicular to the tracking direction.

[0054] See also Figure 6 Objective lens 1 is used to focus a combined beam of light onto a holographic disc 140. The combined beam includes a first light beam 160 for focusing, tracking, and addressing, and a second light beam 170 for reading and writing holographic information. Holographic disc 140 comprises a substrate 1401, a dichroic reflective layer 1402, a holographic medium layer 1403, and a protective layer 1404, arranged in this order. The dichroic reflective layer 1402 reflects the second light beam 170 and transmits the first light beam 160, with the color of the first light beam 160 being different from that of the second light beam 170. Address information pits 1405 are pre-engraved in substrate 1401. The holographic medium layer 1403 stores the data carried by the green light. The protective layer 1404 protects holographic disc 140.

[0055] See also Figure 4 and Figure 6 The reflector 3 is arranged on the first support seat 5 and can rotate relative to the first support seat 5 to change the direction of the light path so that the light emitted from the laser can be accurately focused onto the holographic optical disc 140 through the objective lens 1.

[0056] See also Figure 1 and Figure 6 The focusing movement device 2 moves the first support plate 11 and the objective lens 1 thereon in the focusing direction (i.e., perpendicular to the surface of the holographic disc 140) for precise focusing. The tracking movement device 4 moves the first support base 5, the reflector 3 thereon, and the objective lens 1 in the tracking direction (i.e., parallel to the surface of the storage medium) to facilitate data reading and writing operations. In actual use, the holographic disc 140 is positioned above and the torquer device is positioned below, i.e., the focusing direction is vertical and the tracking direction is horizontal.

[0057] Compared to directly moving the holographic disc 140 and its rotating motor 150, the present invention achieves focusing and tracking by moving the relatively lightweight objective lens 1 and reflector 3, making it easier to operate and control precision. Furthermore, the synchronized tracking of the objective lens 1 and reflector 3 ensures that the incident light maintains a consistent angle of incidence during tracking servo, thus satisfying the requirement for consistent incident angles for both read and write light in a coaxial holographic storage system.

[0058] Please refer to Figure 1 , Figure 4 and Figure 5 In this embodiment, the force moment device further comprises a second support base 6, and the tracking moving device 4 comprises two tracking moving units 41, each of which comprises a permanent magnet 414, a tracking coil 411 and a tracking suspension wire 412. The permanent magnet 414 is arranged on the second support base 6 and located on one side of the tracking coil 411. The tracking coil 411 is arranged on the first support base 5. The tracking coil 411 is arranged on the first support base 5 and the second support base 6. The tracking suspension wire 412 is elastic and has a curved portion. The tracking coil 411 generates a magnetic field when energized, interacts with the magnetic field of the permanent magnet 414 to generate an electromagnetic force in the tracking direction, and cooperates with the elastic force of the tracking suspension wire 412 to move the tracking coil 411 in the tracking direction.

[0059] The second support base 6 bears the permanent magnet 414 and is used in cooperation with the first support base 5. The two ends of the tracking suspension wire 412 are respectively fixed on the two side walls of the second support base 6 by rivets, specifically, two standard copper rivets are sleeved on the tracking suspension wire 412, and then the middle part is fixed on the first support base 5. The tracking suspension wire 412 is connected with the first support base 5 and plays a role in supporting the first support base 5. The tracking suspension wire 412 has a curved portion and is elastic and deformable, so that the first support base 5 can move along with the tracking suspension wire 412 when the tracking suspension wire 412 moves in the tracking direction, and the second support base 6 is not affected. Figure 1 As shown, the tracking suspension wire 412 has a straight portion and an S-shaped curved portion, and the S-shaped curved portion can have a redundant amount. The S-shaped curved portion can also avoid the copper rivet 214 and the focusing coil 211.

[0060] The tracking moving device 4 designed with the permanent magnet 414, the tracking coil 411 and the tracking suspension wire 412 has small size and is convenient for installation and integration. The material of the permanent magnet 414 can be selected as N52, which has very high magnetic energy product and can provide a strong magnetic field. The tracking moving device 4 driven by electromagnetic force has fast response speed, and the distance and speed of tracking movement can be accurately controlled by controlling the size and direction of the current, so that high-precision tracking operation is realized.

[0061] Please refer to Figure 1 , a space rectangular coordinate system is constructed, the focusing direction is the up-down direction (as indicated by the arrow z), the tracking direction is the front-back direction (as indicated by the arrow y), and the left-right direction is as indicated by the arrow x. The tracking suspension wires 412 corresponding to the two tracking moving units 41 are symmetrically arranged on the front and back sides of the first support base 5, and the focusing suspension wires 212 corresponding to the two focusing moving units 21 are symmetrically arranged on the left and right sides of the first support plate 11.

[0062] In the embodiment, the tracking moving unit 41 has two tracking coils 411, which are arranged side by side and are plugged and glued with the first support base 5. Figure 1 As shown, the two tracking coils 411 of the tracking moving unit 41 are arranged side by side along the tracking direction (the front-rear direction, as indicated by the arrow y), and the two tracking moving units 41 are symmetrically arranged on the left and right sides of the first support base 5, and the two tracking moving units 41 have a total of four tracking coils 411.

[0063] In some embodiments, the tracking moving device 4 can be an oil cylinder, a gas cylinder, or an electric cylinder, which is a linear motion mechanism. Similarly, the focusing moving device 2 can also be an oil cylinder, a gas cylinder, or an electric cylinder, which is a linear motion mechanism.

[0064] Please refer to Figure 1 , Figure 2 , Figure 4 and Figure 5 In the embodiment, the focusing moving device 2 includes two focusing moving units 21, which are located on both sides of the objective lens 1. The focusing moving unit 21 includes a focusing coil 211 and a focusing suspension wire 212. The two focusing moving units 21 share one focusing coil 211, which is located inside the tracking coil 411. The focusing coil 211 is arranged on the first support plate 11, and the first support plate 11 is arranged on the first support base 5 through the focusing suspension wire 212. The focusing suspension wire 212 is elastic and has a curved portion. When the focusing coil 211 is energized to generate a magnetic field, it interacts with the magnetic field of the permanent magnet 414 to generate an electromagnetic force in the focusing direction, which is matched with the elastic force of the focusing suspension wire 212 to move the focusing coil 211 along the focusing direction.

[0065] In order to save the volume of the torque converter and optimize the internal space, the focusing moving unit 21 and the tracking moving unit 41 share one permanent magnet 414. If there are two focusing moving units 21 and two tracking moving units 41, there are two permanent magnets 414. In some embodiments, the focusing moving unit 21 and the tracking moving unit 41 can each use one permanent magnet 414.

[0066] The two ends of the focusing suspension wire 212 can be fixed on the two side walls of the first support base 5 through rivets. Specifically, a standard copper rivet 214 can be sleeved on the focusing suspension wire 212, and then the middle part is fixed on the first support base 5. The focusing suspension wire 212 is connected with the first support plate 11, which supports the first support plate 11 and the objective lens 1 thereon. The focusing suspension wire 212 has a curved portion and is elastic and deformable, which facilitates the movement of the first support plate 11 along the focusing direction when the focusing coil 211 moves, while the first support base 5 is not affected. Figure 1As shown, the focusing suspension 212 has a straight portion and an S-shaped curved portion, and the S-shaped curved portion can have a redundancy.

[0067] The focus movement device 2, which utilizes a permanent magnet 414, a focus coil 211, and a focus suspension wire 212, is compact and easy to install and integrate. The electromagnetically driven focus movement device 2 offers a fast response speed. By controlling the magnitude and direction of the current, the distance and speed of focus movement can be precisely controlled, thereby achieving high-precision focusing.

[0068] In this embodiment, the two permanent magnets 414 are symmetrically arranged, with their facing ends having the same polarity. For example, the left permanent magnet 414 has its S pole at the left end and its N pole at the right end, while the right permanent magnet 414 has its S pole at the right end and its N pole at the left end, with the N poles facing each other. The controller adjusts the direction of motion by controlling the direction of the current applied to the focusing coil 211 and the tracking coil 411. For example, if the current direction is positive, the focusing coil 211 points upward and the tracking coil 411 points forward. The controller also adjusts the stroke length by controlling the magnitude of the current applied to the focusing coil 211 and the tracking coil 411.

[0069] See also Figure 1 、 Figure 2 、 Figure 4 and Figure 5 In this embodiment, the focus movement unit 21 further includes a first connecting block 213, to which the focus suspension 212 is connected. The first connecting block 213 is plugged into the first support plate 11, so that the focus suspension 212 is positioned on the first support base 5 via the first connecting block 213. The focus suspension 212 and the first connecting block 213 are conductors. The focus suspension 212, the tracking suspension 412, the first connecting block 213, the focus coil 211, and the tracking coil 411 are electrically connected via wires. These wires are then connected to a controller on one side, forming a loop. This allows the controller to input current to the focus coil 211 and the tracking coil 411. This effectively integrates mechanical support and electrical connection functions, achieving multiple functions with a small number of components and simplifying the structure.

[0070] Preferably, Figure 2 The two focus suspensions of a group of focus moving units 21 share a first connecting block 213, i.e., the upper and lower sides of the first connecting block 213 are respectively connected to the two focus suspensions 212. To avoid a short circuit between the two focus suspensions 212, part of the first connecting block 213 is a conductor and part is an insulator. The insulated part can prevent the two focus suspensions 212 from conducting.

[0071] Preferably, the focusing suspension 212 and tracking suspension 412 can be made of C17200 beryllium copper, which has a certain strength and elasticity, providing both good support and a good deformation margin. The focusing coil 211 is wound from a single wire, and all tracking coils 411 can be wound from a single wire. The focusing suspension 212 and the first connecting block 213 can be welded together, allowing the first connecting block 213 to move with the position of the focusing suspension 212. Similarly, the tracking suspension 412 and the second connecting block 413 can be welded together, allowing the second connecting block 413 to move with the position of the tracking suspension 412.

[0072] Figure 1 As shown, the focusing direction is up and down (as indicated by arrow z), and the tracking direction is forward and backward (as indicated by arrow y). Two first connecting blocks 213 are provided, one for each focus moving unit 21. The first connecting block 213 has a first fixing slot on the side near the first support plate 11. The first fixing slot clamps the left and right sides of the first support plate 11, which can then be secured by gluing. Preferably, the first connecting block 213 is made of a circuit board, with solder pads on the circuit board serving as conductive portions, i.e., the solder pads are connected to the required focus suspension wire 212 and electrical wires. In some embodiments, the first connecting block 213 may be a metal block.

[0073] See also Figure 2 and Figure 5 In this embodiment, the tracking moving unit 41 has two tracking suspensions 412, namely an upper tracking suspension (such as the first upper tracking suspension 4121 and the second upper tracking suspension 4122 described below) and a lower tracking suspension (such as the first lower tracking suspension 4123 and the second lower tracking suspension 4124 described below), which are located on the upper and lower sides of the first support plate 11. The upper tracking suspension is located above the lower tracking suspension. The cross-sectional area of ​​the upper tracking suspension is different from that of the lower tracking suspension, which can keep the vertical axis torquer stable during the tracking servo process and prevent it from tilting significantly, thereby avoiding affecting the incident angle of the focused light spot. Optionally, the cross-sectional area of ​​the upper tracking suspension is larger than that of the lower tracking suspension. Or in some embodiments, the cross-sectional area of ​​the upper tracking suspension is smaller than that of the lower tracking suspension. Please refer to Figures 1 to 5 In this embodiment, the torquer device further includes a yoke 7 having a U-shaped structure. The permanent magnet 414, tracking coil 411, and focusing coil 211 are all located within the yoke 7, and the permanent magnet 414 is plugged into the yoke 7. The function of the yoke 7 is to confine the magnetic field within a certain range and maintain the magnetic field stable within this range. Preferably, the yoke 7 can be made of 1j85 Permalloy, which has the characteristics of high magnetic permeability and low hysteresis loss, and can effectively guide and concentrate the magnetic field.

[0074] Figure 1 、 Figure 3 As shown, the yoke 7 is in an inverted U-shape, with a total of two tracking moving units 41, and a total of two yokes 7. The two yokes 7 are located on the left and right sides of the first support plate 11. The permanent magnet 414 is located in the middle of the yoke 7, and a groove 71 is provided at the top of the yoke 7 (inverted U-shaped space). The permanent magnet 414 is plugged into the groove 71 to achieve fixation. The yoke 7 and the permanent magnet 414 form a mountain shape, and the two spaces inside the mountain shape contain the focusing coil 211 and the tracking coil 411 respectively. The focusing coil 211 is in a square shape, with an opening in the center extending up and down. The two sides of the focusing coil 211 are respectively located in a yoke 7 (U-shaped space), specifically in the direction where the permanent magnet 414 is close to the first support plate 11. The tracking coil 411 is in a square shape, with an opening in the center extending left and right. There are protrusions on the left and right side walls of the first support base 5, respectively. The tracking coil 411 is plugged into the protrusions to achieve fixation. Optionally, a gluing step can be performed after plugging in to further increase the stability of the connection.

[0075] See also Figure 1 In this embodiment, the focusing suspension line 212 extends along the tracking direction, the tracking suspension line 412 is perpendicular to the focusing suspension line 212, and the extending direction is perpendicular to the focusing direction. The focusing suspension line 212 and the tracking suspension line 412 are staggered up and down. Figure 1 As shown, the focusing direction is vertical, and the tracking direction is front-to-back. The focusing suspension 212 extends in the tracking direction, and the tracking suspension 412 extends in the left-right direction. The orthogonal design of the focusing suspension 212 and the tracking suspension 412, as well as their vertical offset, allows for independent control of movement in the two directions (focusing and tracking), reducing interference between the different movement directions.

[0076] See also Figure 1 、 Figure 4 and Figure 5 In this embodiment, the tracking movement unit 41 also includes a second connecting block 413. The tracking suspension wire 412 passes through the second connecting block 413 and is plugged into the first support base 5, so that the tracking suspension wire 412 is positioned on the first support base 5 through the second connecting block 413. The tracking suspension wire 412 and the second connecting block 413 are conductors. The focusing suspension wire 212 / tracking suspension wire 412, the second connecting block 413, the focusing coil 211 / tracking coil 411 are electrically connected by wires. These are then connected to a controller on one side, forming a loop. This allows the controller to input current to the focusing coil 211 and the tracking coil 411. This effectively integrates mechanical support and electrical connection functions, achieving multiple functions with a small number of components and simplifying the structure.

[0077] Figure 1As shown, the focusing direction is the up-down direction, the tracking direction is the front-back direction, the tracking moving unit 41 has two tracking suspension lines 412 arranged up and down, a total of two tracking moving units 41, a total of four tracking suspension lines 412, the structure is as follows Figure 4 、 Figure 5 As shown. Each tracking suspension wire 412 corresponds to one first connecting block 213, and each tracking movable unit 41 has two second connecting blocks 413. The second connecting block 413 has a second fixing slot on the side near the first support base 5. This second fixing slot clamps the front and right sides of the first support base 5, and can then be secured by gluing. Preferably, the second connecting block 413 is made of a circuit board, with solder pads on the circuit board serving as conductive areas, specifically connecting the solder pads to the desired focusing suspension wire 212 and electrical wires. In some embodiments, the second connecting block 413 may be a metal block.

[0078] See also Figure 1 In this embodiment, the tracking movement unit 41 further includes a third connecting block 415, which is located outside the second support base 6. The tracking suspension wire 412 sequentially passes through the second support base 6 and the fourth connecting block, and can be fixed by rivet 2. The shape of the third connecting block 415 can be adapted to the shape of the side wall of the second support base 6. The third connecting block 415 can cover the side wall of the second support base 6, and preferably, the third connecting block is insulated from the second support base. Figure 1 The third connecting block 415 and the sidewall of the second support base 6 are both concave in shape. Preferably, the third connecting block 415 is a conductor, and can be made of a circuit board, metal, or non-metal, to form an electrical connection with the controller. Part of the third connecting block 415 is conductive, while part is insulated. The insulated portion can prevent short circuits.

[0079] See also Figure 4 and Figure 5 In this embodiment, the four focusing suspensions 212 can be divided into a first upper focusing suspension 2121, a second upper focusing suspension 2122, a first lower focusing suspension 2123, and a second lower focusing suspension 2124. The four tracking suspensions 412 can be divided into a first upper tracking suspension 4121, a second upper tracking suspension 4122, a first lower tracking suspension 4123, and a second lower tracking suspension 4124. The four tracking coils 411 can be divided into a first tracking coil, a second tracking coil 4111, a third tracking coil, and a fourth tracking coil 4112. All four are made from a single wire. The first and second tracking coils 4111 form a tracking moving unit 41 located on the left, while the third and fourth tracking coils 4112 form a tracking moving unit 41 located on the right.

[0080] The second connecting block 413 assembled with the first upper tracking suspension wire 4121 is electrically connected to the copper rivet 214 sleeved on the second upper focusing suspension wire 2122 through the electric wire 416, wherein the electric wire 416 can be wound on the limiting column 51 on the outer side wall of the first support seat 5, and then the first connecting block 213 assembled with the second upper focusing suspension wire 2122 is connected to the focusing coil 211 through the electric wire 215.

[0081] The second connecting block 413 assembled with the first lower tracking suspension wire 4123 is electrically connected to the copper rivet 214 sleeved on the second lower focusing suspension wire 2124 through the electric wire 417, wherein the electric wire 417 can be wound on the limiting column 52 on the outer side wall of the first support seat 5, and then the first connecting block 213 assembled with the second lower focusing suspension wire 2124 is connected to the focusing coil 211 through the electric wire 216.

[0082] The second connecting block 413 assembled with the second upper tracking suspension wire 4122 is electrically connected to the fourth tracking coil 4112 through the electric wire 418, and the second connecting block 413 assembled with the second lower tracking suspension wire 4124 is electrically connected to the second tracking coil 4111 through the electric wire 419.

[0083] The controller on one side can be electrically connected to the tracking suspension wire 412 through the electric wire, and the focusing coil 211 and the tracking coil 411 are pressurized through the above-mentioned circuit structure. The controller can receive the focusing error signal, the tracking error signal, the address signal and the like reflected by the holographic optical disc 140 to the four-quadrant detector 130, and process the signals through a control algorithm, and then act on the focusing coil 211 and the tracking coil 411.

[0084] Please refer to Figure 4 In the embodiment, the reflector 3 is rotatably arranged relative to the first support seat 5, that is, the reflector 3 can rotate on the first support seat 5 to adjust the track of the incident light. The reflector 3 can be hinged to the first support seat 5 through the second support plate 31, and the side edge of the second support plate 31 has two cylinders, so that it can rotate after being connected to the first support seat 5, thereby adjusting the direction of the optical axis of the incident light to the objective lens 1.

[0085] In the embodiment, the material of the second support seat 6 can be metal, preferably 1j85 permalloy.

[0086] In the embodiment, the material of the first support plate 11 and the first support seat 5 can be red wax for 3D printing.

[0087] Please refer to Figures 1 to 6 The embodiment provides a coaxial holographic storage system, which comprises:

[0088] a semiconductor laser 8 for emitting a first light beam 160, the first light beam 160 carrying a focusing error signal and a tracking error signal;

[0089] A single longitudinal mode laser, configured to emit a second light 170, the second light carrying holographic data information;

[0090] a polarization beam splitter 9, provided on one side of the semiconductor laser 8, for reflecting the first light 160;

[0091] A collimating lens 100 is provided on one side of the polarization beam splitter 9 and is used to collimate the first light 160 reflected by the polarization beam splitter 9;

[0092] A dichroic beam splitter 110 is provided on one side of the collimating lens 100 and is used to combine the first light 160 and the second light 170;

[0093] A quarter wave plate 120 is provided on one side of the dichroic beam splitter 110 and is used to allow the combined light beam to pass through;

[0094] a torquer device, such as the torquer device of the coaxial holographic storage system described in any of the above embodiments, the torquer device being disposed on one side of the quarter-wave plate 120, the reflector 3 of the torquer device being used to reflect the combined light beam transmitted through the quarter-wave plate 120, the objective lens 1 of the torquer device being used to converge a first light beam 160 of the combined light beam onto an ideal focal plane corresponding to the holographic optical disc 140, and to converge a second light beam 170 of the combined light beam onto an ideal focal plane corresponding to the holographic optical disc 140;

[0095] Among them, the torquer device also includes a four-quadrant detector 130 and a controller. The four-quadrant detector 130 is used to detect the focusing error signal and the tracking error signal carried by the first light 160. The controller is used to control the focusing moving device 2 according to the focusing error signal to move the first support plate 11 and the objective lens 1 along the focusing direction, and control the tracking moving device 4 according to the tracking error signal to move the first support seat 5, the reflector 3 and the objective lens 1 along the tracking direction.

[0096] The first light 160 can be red light, and the second light 170 can be green light. It should be noted that this embodiment is not limited to these two colors of light and can be adjusted according to actual conditions. The red light is responsible for focusing, tracking, and addressing, while the green light is responsible for reading and writing holographic information.

[0097] See also Figure 6 The holographic optical disc 140 includes a substrate 1401, a color separation reflection layer 1402, a holographic medium layer 1403 and a protective layer 1404 arranged in sequence, wherein the color separation reflection layer 1402 is a red-transmitting and green-transmitting layer that reflects green light and transmits red light.

[0098] See also Figure 6The red light emitted by the semiconductor laser 8 is reflected by a polarizing beam splitter 9 (PBS), collimated by a collimating lens 100, and combined with green light by a dichroic beam splitter 110 (DBS), the green light being emitted by a single longitudinal mode laser. After the red light is combined with the green light, the red light passes through a 1 / 4 wave plate 120 and a mirror 3, and is focused on a substrate 1401 of a holographic optical disc 140 and a red-through-green-reflection layer (i.e. a red light ideal focal plane) by converging of an objective lens 1. The green light is focused on the red-through-green-reflection layer and a holographic medium layer 1403 (i.e. a green light ideal focal plane). The red light ideal focal plane and the green light ideal focal plane are located at the same radius position of the holographic optical disc but at different layers.

[0099] When the holographic optical disc 140 deviates from the red light ideal focal plane in a focusing direction, a four-quadrant detector 130 detects a focusing error signal. At this time, a controller receives the information and changes an applied current on a focusing coil 211, so that the objective lens 1 moves in the focusing direction, and the focal points of the red light and the green light fall on the respective ideal focal planes. This process is called focusing servo.

[0100] When the holographic optical disc 140 completes the focusing servo, the light spot at the focal point of the red light does not necessarily fall on a track where address information pits 1405 are located. At this time, the four-quadrant detector 130 detects a tracking error signal. The controller receives the information and changes an applied current on a tracking coil 411, so that the first support 5 moves in a tracking direction, and the focal point of the red light falls on a track of the holographic optical disc 140. This process is called tracking servo.

[0101] In the embodiment, the focusing error signal can be achieved by astigmatism. The astigmatism uses a cylindrical lens to generate astigmatism. When the objective lens 1 is defocused, the cylindrical lens converts different defocusing amounts into changes in light energy distribution in different directions. After detection by a photoelectric detector, an error signal is obtained. The four-quadrant detector 130, also called a PDIC, can be adjusted to accurately make the light spot a perfect circle when in focus, and the error signal FE (Focusing Error) output is 0. When defocused, the light spot is an ellipse in the horizontal or vertical direction, and the error signal FE output is not 0. Thus, a defocusing error signal is obtained, as shown in FIG. 4. Figure 7 When the moment device is controlled to move in the focusing direction, the current drives the objective lens 1 to move up and down. When the optical disc approaches or moves away from the focal point, the value of the focusing error signal FE fluctuates. Therefore, the signal becomes the basis for focusing control.

[0102] When the moment device is controlled by the controller to move in the focusing direction, the current drives the objective lens 1 to move up and down. When the optical disc approaches or moves away from the focal point, the value of the focusing error signal FE fluctuates. Therefore, the signal becomes the basis for focusing control. Because its shape is similar to the letter S, it is named S curve, as shown in FIG. 5. Figure 8 shown.

[0103] Tracking error signal detection can be achieved using the push-pull method. To facilitate this, the holographic disc 140 is manufactured with a wobble groove. The raised portions are called lands, and the recessed portions are called grooves. User signals are typically recorded in the grooves, but sometimes they are recorded on both the lands and grooves. When the beam spot is correctly focused on the centerline of the pregroove 1406, the returned beam spot will fall exactly in the center of the four quadrants of the PDIC. After photoelectric conversion, the radial push-pull (RPP) signals output from quadrants A, B, C, and D meet the requirements. When the beam spot deviates downward from the centerline of the pregroove 1406, more light energy strikes the lands below the pregroove 1406, causing the returned beam spot to fall more heavily in quadrants D and C. When the beam spot deviates upward from the centerline of the pregroove 1406, more light energy strikes the lands above the pregroove 1406, causing the returned beam spot to fall more heavily in quadrants A and B. According to the positive and negative, size of the RPP signal, the direction and distance of the focus spot offset from the optical disc track can be determined. Figure 9 As shown, the tracking coil 411 is controlled according to the signal. Since the RPP signal also reflects the tracking error, it is also called the TE (Tracking Error) signal.

[0104] It should be mentioned that, compared with the torquer devices previously used on ordinary optical discs, this method solves the problem that the classic torquer device cannot drive the large-mass objective lens 1 and cannot keep the incident light at the same incident angle during tracking servo. It meets the requirement that the incident angles of the read and write light need to be consistent in the coaxial holographic storage system. If a single objective lens 1 is used for tracking servo, the angle of the incident light near the holographic disc 140 will change. If the reflector 3 and the objective lens 1 of the present application are moved synchronously, the angle of the incident light near the holographic disc 140 will not change. The imaging quality of red light and green light on the imaging surfaces of their respective detectors can be improved.

[0105] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection of the present utility model. Therefore, based on the innovative concept of the present utility model, changes and modifications to the embodiments described herein, or equivalent structural or process transformations made using the contents of the present utility model specification and drawings, and direct or indirect application of the above technical solutions to other related technical fields are all included in the scope of protection of the present utility model patent.

Claims

1. A torquer device for a coaxial holographic storage system, characterized in that: The invention comprises an objective lens, a first support plate, a first support seat, a focusing movement device, a reflective mirror and a tracking movement device, wherein the objective lens is arranged on the first support plate, the first support plate is arranged on the first support seat via the focusing movement device, the focusing movement device is used to move the first support plate and the objective lens along a focusing direction, the reflective mirror is arranged on the first support seat, the first support seat is arranged on the tracking movement device, and the tracking movement device is used to move the first support seat, the reflective mirror and the objective lens along a tracking direction, wherein the focusing direction is perpendicular to the tracking direction; The torquer device also includes a second support seat, and the tracking movement device includes two tracking movement units. The tracking movement unit includes a permanent magnet, a tracking coil and a tracking suspension wire. The permanent magnet is arranged on the second support seat, and the permanent magnet is located on one side of the tracking coil. The tracking coil is arranged on the first support seat, and the tracking suspension wire is arranged on the first support seat and the second support seat. The tracking suspension wire has an elastic and curved part, wherein the tracking coil is energized to generate a magnetic field, which interacts with the magnetic field where the permanent magnet is located to generate an electromagnetic force in the tracking direction, and cooperates with the elastic force of the tracking suspension wire to make the tracking coil move along the tracking direction.

2. The torquer device according to claim 1, characterized in that: The focusing moving device includes two focusing moving units, and the two focusing moving units are located on both sides of the objective lens. The focusing moving units include a focusing coil and a focusing suspension. The two focusing moving units share one focusing coil, and the focusing coil is located on the inner side of the tracking coil. The focusing coil is arranged on the first support plate, and the first support plate is arranged on the first support seat through the focusing suspension. The focusing suspension is curved and elastic, wherein the focusing coil generates a magnetic field when energized, and interacts with the magnetic field where the permanent magnet is located to generate an electromagnetic force in the focusing direction, which is combined with the elastic force of the focusing suspension to make the focusing coil move along the focusing direction.

3. The torquer device according to claim 2, characterized in that: The focusing moving unit also includes a first connecting block, the focusing suspension is connected to the first connecting block, and the first connecting block is plugged into the first support plate so that the focusing suspension is arranged on the first support seat through the first connecting block. The focusing suspension and the first connecting block are conductors, and the focusing suspension / the tracking suspension, the first connecting block, and the focusing coil / the tracking coil are electrically connected through wires.

4. The torquer device according to claim 2, characterized in that: It also includes a yoke, which is a U-shaped structure. The permanent magnet, the tracking coil, and the focusing coil are all located inside the yoke, and the permanent magnet is plugged into the yoke.

5. The torquer device according to claim 2, characterized in that: The focusing suspension line extends along the tracking direction, the tracking suspension line is perpendicular to the focusing suspension line, and the extending direction is perpendicular to the focusing direction. The focusing suspension line and the tracking suspension line are staggered up and down.

6. The torquer device according to claim 5, characterized in that: The tracking coil has a curved portion that avoids the focusing coil.

7. The torquer device according to claim 1, characterized in that: The tracking movement unit has two tracking suspension wires, namely an upper tracking suspension wire and a lower tracking suspension wire. The cross-sectional area of ​​the upper tracking suspension wire is different from the cross-sectional area of ​​the lower tracking suspension wire.

8. The torquer device according to claim 1, characterized in that: The tracking moving unit also includes a second connecting block, the tracking suspension wire is connected to the second connecting block, and the second connecting block is plugged into the first support seat so that the tracking suspension wire is arranged on the first support seat through the second connecting block. The tracking suspension wire and the second connecting block are conductors, and the tracking suspension wire, the second connecting block, and the tracking coil are electrically connected through wires.

9. The torquer device according to claim 1, characterized in that: The focusing moving device includes two focusing moving units, and the two focusing moving units are located on both sides of the objective lens. The focusing moving units include a focusing coil and a focusing suspension. The two focusing moving units share one focusing coil. The focusing coil is arranged on the first support plate and is located on one side of the permanent magnet. The first support plate is arranged on the first support seat through the focusing suspension. The focusing suspension is curved and elastic. When the focusing coil is energized, a magnetic field is generated, which interacts with the magnetic field of the permanent magnet to generate an electromagnetic force in the focusing direction, and cooperates with the elastic force of the focusing suspension to move the focusing coil along the focusing direction.

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