JP2008004140A - Optical head device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical head device and its manufacturing method in which interference of optical elements and an objective lens drive device can be prevented even if tilt adjustment of the whole objective lens drive device incorporating a magnetic drive circuit is performed when the optical elements and the objective lens drive device are arranged so as to overlap in the up and down direction. <P>SOLUTION: When an optical device is manufactured, when a tilt angle is adjusted in a state in which an objective lens drive device 9 is arranged at a concave part of a device frame, before a yoke 952 of outside front side of the yoke 95 and a collimate-lens 56 interfere, either of projection parts 991 and 992 interfere with the device frame 2. Therefore, deviation of an optical axis of collimate-lens 56 caused by interference of the outside front side yoke 952 of the yoke 95 and the collimate-lens 56 can be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical head device in which an objective lens driving device for driving an objective lens in a tracking direction and / or a focusing direction is mounted on a device frame, and a method for manufacturing the same.

  In an optical head device used for reproduction and recording of an optical recording disk (optical recording medium) such as a CD or DVD, a light emitting element, an objective lens driving device for driving an objective lens in a tracking direction and / or a focusing direction, and a light emitting element And an optical system that guides the light emitted from the light to the objective lens. In such an optical head device, coma aberration increases when the light emitted from the objective lens is tilted. Therefore, it is necessary to fix the objective lens driving device on the device frame after adjusting the inclination on the device frame.

  In performing such adjustment, a method has been proposed in which the objective lens driving device is tilted with a jig or the like to adjust the tilt angle and then fixed. That is, the tilt angle of the movable part is adjusted by fixing the magnetic circuit to the base in advance (see, for example, Patent Document 1).

Such a method is suitable for downsizing and thinning of the optical head device because it is not necessary to provide a mechanism for adjusting the tilt angle in the optical head device.
JP 2001-14699 A

  However, in the case of the method according to Patent Document 1, since the magnetic circuit and the coil are separated from each other, the characteristics are determined only after the objective lens driving device is configured on the device frame. If there is a problem, the entire optical head device becomes a defective product.

  Here, the inventor of the present application proposes that the tilt angle adjustment is performed in the state of the objective lens driving device in which the magnetic driving circuit is also incorporated. According to such a method, the objective lens driving device is mounted on the device frame. Before starting, the characteristics of the objective lens driving device can be grasped.

  However, in order to reduce the size and thickness of the optical head device, there are cases where a collimating lens or the like has to be arranged in a position overlapping with the yoke or the like of the objective lens driving device in the vertical direction. In this case, if the method of adjusting the tilt angle of the entire objective lens driving device incorporating the magnetic driving circuit is adopted, the collimating lens already fixed with the optical axis adjusted interferes with the objective lens driving device, and the collimating lens There is a problem that the optical axis is shifted.

  In view of the above problems, the object of the present invention is to adjust the inclination of the entire objective lens driving device incorporating a magnetic driving circuit when the optical element and the objective lens driving device are arranged so as to overlap in the vertical direction. An object of the present invention is to provide an optical head device capable of preventing interference between an optical element and an objective lens driving device even when the operation is performed, and a manufacturing method thereof.

  In order to solve the above problems, in the present invention, a light emitting element, an objective lens driving device that drives an objective lens in a tracking direction and / or a focusing direction, and an optical system that guides light emitted from the light emitting element to the objective lens In the optical head device mounted on the device frame, when the optical axis direction of the objective lens is the vertical direction, the device frame includes a concave portion for disposing the objective lens driving device, and the objective lens driving device The optical system includes an optical element that is fixed at a position protruding inward from an inner peripheral wall in the recess and overlaps with a part of the objective lens driving device in the vertical direction. Of the portions where the element and the objective lens driving device overlap in the vertical direction, the separation distance at the first overlapping portion with the shortest separation distance is the mounting distance. Of the portion of the frame and the objective lens driving device overlaps in the vertical direction, the distance is equal to or longer than the distance in the second overlapping portion of the shortest.

  In the present invention, a light emitting element, an objective lens driving device that drives the objective lens in the tracking direction and / or the focusing direction, and an optical system that guides the emitted light from the light emitting element to the objective lens are mounted on the apparatus frame, The apparatus frame is formed with a concave portion in which the objective lens driving device is disposed, and a portion overlapping with the objective lens driving device in the vertical direction is formed, and the optical system has an inner side from an inner peripheral wall in the concave portion. In the method of manufacturing an optical head device including an optical element that is fixed at a protruding position and overlaps with a part of the objective lens driving device in the vertical direction, when the objective lens driving device is disposed in the concave portion, Among the portions where the optical element and the objective lens driving device overlap in the vertical direction, the separation distance at the first overlapping portion where the separation distance is the shortest is the front. Among the portions in which the apparatus frame and the objective lens driving device overlap in the vertical direction, the separation distance is set to be longer than the separation distance in the second overlapping portion, and the optical system including the optical element is After fixing to the apparatus frame, the objective lens driving device is disposed in the concave portion, and after adjusting the inclination of the objective lens driving device, the objective lens driving device is fixed in the concave portion.

  In the present invention, among the portions where the optical element and the objective lens driving device overlap in the vertical direction, the separation distance at the first overlapping portion where the separation distance is the shortest is the device frame and the objective lens driving device. Among the overlapping portions in the vertical direction, the separation distance is longer than the separation distance in the second overlapping portion with the shortest distance. For this reason, after the optical system including the optical element is fixed to the apparatus frame, when the tilt of the objective lens driving apparatus is adjusted in the recess, the objective lens driving apparatus is installed before the interference with the optical element. Interfering with the frame.

  In the present invention, it is preferable that the second overlapping portion is located in the vicinity of the first overlapping portion.

  In the present invention, the portion constituting the first overlapping portion and the second overlapping portion in the objective lens driving device is, for example, a yoke used in a magnetic drive mechanism for driving the objective lens.

  In the present invention, for example, a part of the yoke is positioned above the optical element to form the first overlapping portion, and the other part is vertically arranged on the upper surface of the apparatus frame around the recess. Projections projecting from the left and right sides perpendicular to the optical axis direction are formed up to the overlapping position, and the projections constitute the second overlapping section.

  In the present invention, after the optical system including the optical element is fixed to the apparatus frame, when the inclination of the objective lens driving apparatus is adjusted in the recess, the objective lens driving apparatus interferes with the apparatus frame before interfering with the optical element. . Therefore, when the optical element and the objective lens driving device are arranged so as to overlap in the vertical direction, the optical element and the objective lens driving device can be adjusted even if the inclination angle of the entire objective lens driving device including the magnetic driving circuit is adjusted. Can be prevented, and an optical axis shift or the like due to interference with the objective lens driving device can be avoided.

  An optical head device to which the present invention is applied will be described below with reference to the drawings.

[Embodiment 1]
(overall structure)
1 and 2 are a perspective view of an optical head device to which the present invention is applied as viewed from the side from which light is emitted from an objective lens, and a perspective view of a state in which a main body cover and an actuator cover are removed from the optical head device. . 3 and 4 are an exploded perspective view of the optical head device shown in FIG. 1, and a perspective view of a state in which a metal cover, an actuator cover, and an objective lens driving device are removed from the optical head device.

  The optical head device 1 of this embodiment shown in FIGS. 1 to 4 reproduces and / or records information on an optical recording medium such as a CD and a DVD. The optical head device 1 has a metal device frame 2 made of a die-cast product such as magnesium or zinc, and a guide shaft and a feed screw shaft of a disk drive device are engaged with each of both ends of the device frame 2. A first bearing 21 and a second bearing 22 are formed. One side surface of the device frame 2 is curved in an arc shape to prevent interference when approaching a spindle motor (not shown) of the disk drive mechanism.

  On the upper surface side of the apparatus frame 2, the objective lens 91 is located substantially at the center. A metal body cover 80 is placed on the side where the first bearing 21 is located with respect to the objective lens 91. The body cover 80 is engaged with an upper plate portion 81 that covers the upper surface of the device frame 2 and a protrusion 28 that is bent downward from one side edge of the upper plate portion 81 and formed on the side surface of the device frame 2. The positioning projection 29 protruding upward from the device frame 2 is fitted into the small hole 83 formed in the upper surface portion.

  The optical head device 1 according to the present embodiment can record and reproduce information with respect to a DVD disk and a CD disk by using a first laser beam having a wavelength of 650 nm and a second laser beam having a wavelength of 780 nm. A first laser light source device 30 having an AlGaInP-based semiconductor laser (laser diode) that emits a first laser beam having a wavelength of 650 nm; And a second laser light source device 40 equipped with an AlGaAs semiconductor laser (laser diode) that emits a second laser beam of 780 nm band. Here, the first laser beam and the second laser beam are DVDs that are optical recording disks via an optical system including a plurality of optical elements arranged in an optical path from the laser light source devices 30 and 40 toward the optical recording disk. An optical element guided to a system disk or CD system disk and constituting this optical system is also mounted on the apparatus frame 2. The return light from the optical recording disk is also guided to the common signal detection light receiving element 50 via the optical system, and the optical element that defines the optical path for the return light and the signal detection light receiving element 50 are also included in the apparatus frame 2. It is mounted on.

  In the optical head device 1 of the present embodiment, the optical system includes an optical path composition that transmits the laser light emitted from the first laser light source device 30 and reflects the laser light emitted from the second laser light source device 40. Polarizing prism 52, a half mirror 53 that partially reflects the laser light emitted from the polarizing prism 52, a quarter wavelength plate 55 for the laser light reflected by the half mirror 53, and this quarter wavelength plate A collimating lens 56 for converting the laser light transmitted through 55 into parallel light, a rising mirror 57 for raising the parallel light toward the optical recording disk, and a recording surface of the optical recording disk for the laser light from the rising mirror 57 And an objective lens 91 for converging. Further, in the optical system, the return light reflected by the recording surface of the optical recording disk is guided to the signal detecting light receiving element 50 through the rising mirror 57, the collimating lens 56, the quarter wavelength plate 55, and the half mirror 53. A sensor lens (not shown) is also included for providing astigmatism when being applied. A light receiving element 51 for monitoring is disposed behind the half mirror 53 when viewed from the polarizing prism 52. Note that a diffraction element 54 in which a half-wave plate is integrally formed is disposed between the first laser light source device 30 and the polarizing prism 52, and the second laser light source device 40 and the polarizing prism 52 are connected to each other. A diffraction element 58 and a relay lens 59 are disposed between them.

  The objective lens 91 is servo-controlled for the position in the tracking direction and the focusing direction by the objective lens driving device 9, and such an objective lens driving device 9 is also mounted on the apparatus frame 2. In this embodiment, a wire suspension type is used as the objective lens driving device 9, and the description of the objective lens driving device 9 will be described later. The objective lens driving device 9 can also perform tilt control for adjusting the tilt of the objective lens 91 in the jitter direction. The periphery of the objective lens 91 is covered with an actuator cover 85 having a rectangular frame shape.

  A flexible substrate 70 is disposed on the upper surface of the device frame 2, and a main body cover 80 and an actuator cover 85 are disposed on the flexible substrate 70. A driving IC (not shown) is formed on the flexible substrate 70, and the first laser light source device 30 and the second laser light source device are utilized by using an end portion of the flexible substrate 70. 40, electrical connection to the light receiving element 50 for signal detection and the light receiving element 51 for monitoring is performed.

(Objective lens drive unit and its peripheral configuration)
FIG. 5 is an explanatory diagram showing an overlapping portion between the yoke and the collimating lens (“optical element” in the present embodiment) and an overlapping portion between the yoke and the apparatus frame in the optical head device shown in FIG.

  As shown in FIGS. 1 to 4, in the optical head device 1 of this embodiment, the device frame 2 is formed with a recess 25 that opens upward, and the objective lens driving device 9 is placed in the recess 25. Be placed.

  As shown in FIG. 4, the recess 25 includes a pair of front wall 251 and rear wall 252 that face each other in the tangential direction of the optical head device 1 (the front-rear direction in which the bearings 21 and 22 are formed in the device frame 2). A pair of side walls 253 and 254 facing each other in the tracking direction (left and right direction) are surrounded by protrusions 26 facing the front wall 251 and the rear wall 252 from the bottom 250 at positions spaced apart from the four wall surfaces in the recess 25. Standing up.

  A pair of left and right adhesive injection grooves 231 are formed on the front surface of the protrusion 26. In addition, an adhesive injection groove 232 is formed in a portion of the side walls 253 and 254 close to the rear wall 252, and a pair of left and right adhesive injection grooves 233 are formed in the front wall 251.

  Here, a rising mirror 57 is bonded and fixed at substantially the center of the recess 25. In addition, an opening (not shown) that secures an optical path is formed in the front wall 251, and a collimator lens 56 is bonded and fixed to the front wall 251 so as to cover the opening. For this reason, the collimating lens 56 is in a state of protruding from the front wall 251 in the recess 25 to the inside of the recess 25.

  As shown in FIG. 3, the objective lens driving device 9 includes a lens holder 92 that holds the objective lens 91 and a holder that supports the lens holder 92 movably in the tracking direction and the focusing direction with a plurality of wires 93. A support portion 94 and a yoke 95 fixed to the apparatus frame 2 are provided. The objective lens driving device 9 includes a magnetic driving circuit including a driving coil 97 attached to the lens holder 92 and a driving magnet 98 attached to the yoke 95. The holder support portion 94 has a built-in gel pot, and a wiring board 90 for feeding power to the wire 93 is pasted on the back surface. The drive coil 97 includes a focusing drive coil, a tracking drive coil, and a tilt drive coil. The drive magnet 98 includes a pair of left and right permanent magnets facing the front surface of the lens holder 92 and a rear surface of the lens holder 92. A pair of opposing left and right permanent magnets is included. In such an objective lens driving device 9, the drive coil 97 is energized through the wire 93 and the energization is controlled so that the objective lens 91 held by the lens holder 92 is moved in the tracking direction and the optical recording disk. Drive in the focusing direction. The objective lens driving device 9 can also perform tilt control for adjusting the tilt of the objective lens 91 in the jitter direction.

  As shown in FIG. 5, the yoke 95 used in the objective lens driving device 9 of the present embodiment is composed of a single magnetic plate that has been pressed, and stands on the bottom plate portion 951 and the front end side of the bottom plate portion 951. A front outer yoke 952, a rear outer yoke 953 standing on the rear end side of the bottom plate portion 951, and a pair of inner yokes 954 and 955 standing on the left and right ends of the bottom plate portion 951 are provided. Further, the yoke 95 includes a counter plate portion 957 that is opposed to the rear outer yoke 953 in the rear, and the counter plate portion 957 is connected to the rear outer yoke 953 by a connecting plate portion 958. Here, the counter plate portion 957 is fixed to a holder support portion 94 that supports the lens holder 92 via a wire 93. Therefore, in the objective lens driving device 9 of this embodiment, the lens holder 92 that holds the objective lens 91 and the drive coil 97 is supported by the holder support portion 94 via the wire 93, while the yoke 95 is also the holder support portion 94. The entire objective lens driving device 9 is configured as one assembly.

  In the objective lens driving device 9 configured as described above, the front outer yoke 952 is formed with a plurality of circular notches 950 so as to avoid the collimating lens 56 (optical element), and has an arch shape. Here, the front outer yoke 952 of the yoke 95 overlaps with the collimating lens 56 in the vertical direction (the optical axis direction of the objective lens 91) in a state where the objective lens driving device 9 is disposed in the recess 25, and the front outer yoke 952 is overlapped. Among the overlapping portions of the collimating lens 56 and the collimating lens 56, the separation distance at the first overlapping portion 11 with the shortest separation distance is the dimension L1.

  Further, the front outer yoke 952 of the yoke 95 is formed with a pair of protrusions 991 and 992 toward the left and right sides, and the protrusion 992 of the pair of protrusions 991 and 992 is formed on the upper surface of the apparatus frame 2. The portion where the two overlap in the vertical direction is a step portion 272 that is one step lower than the highest region on the upper surface of the apparatus frame 2. Further, on the upper surface of the device frame 2, a portion where the protrusion 991 overlaps in the vertical direction is a hole 271 whose bottom is one step lower than the highest region on the upper surface of the device frame 2. Here, among the portions where the objective lens driving device 9 overlaps the device frame 2 including the yoke 95, the second overlapping portion 12 with the shortest separation distance is the overlapping portion between the protrusion 991 and the bottom of the hole 271. And a protrusion 992 and a step 272. The objective lens driving device 9 is fixed to the device frame 2 after adjusting the inclination on the device frame 2 as indicated by an arrow A. Therefore, according to the adjustment result, when the second overlapping portion 12 having the shortest separation distance is formed by the overlapping portion of the protruding portion 992 and the bottom portion of the hole 271, the overlapping portion of the protruding portion 992 and the stepped portion 272. In some cases, both of these overlapping portions may be included.

In any of these cases, if the separation distance at the second overlapping portion 12 is a dimension L2, the separation distance at the first overlapping portion 11 (dimension L1) and the separation distance at the second overlapping portion 12 (dimension) L2) and the following conditions: dimension L1> dimension L2
Holds. That is, the separation distance (dimension L1) at the first overlapping portion 11 is always longer than the separation distance (dimension L2) at the second overlapping portion 12. Therefore, when the optical head device 1 is assembled by the following method, even if the tilt angle of the objective lens driving device 9 is adjusted when the front outer yoke 952 of the yoke 95 and the collimating lens 56 overlap in the vertical direction, Before the front outer yoke 952 of the yoke 95 interferes with the collimating lens 56, one of the pair of protrusions 991 and 992 interferes with the apparatus frame 2.

(Manufacturing method of optical head device)
In manufacturing the optical head device 1 of this embodiment, first, as shown in FIG. 4, an optical system such as a polarizing prism 52, a half mirror 53, a quarter wavelength plate 55, a collimating lens 56, and a rising mirror 57 is used. Then, it is fixed to the apparatus frame 2 in a state where the optical axis is adjusted.

  Next, as shown in FIG. 2, in the state where the entire objective lens driving device 9 is configured as one assembly, the apparatus frame is supported while the holder support portion 94 of the objective lens driving device 9 is supported using a robot hand or a jig. 2 in the recess 25.

  Next, laser light is emitted from the first laser light source device 30 or the second laser light source device 40, and the light emitted through the objective lens 91 or the detection result of the signal detecting light receiving element 50 is observed. While moving the robot hand or jig, the position of the holder support portion 94 of the objective lens driving device 9 is adjusted. Further, the robot hand or jig is tilted, the holder support portion 94 is tilted in the direction indicated by the arrow A, and the tilt angle of the objective lens 91 (the tilt angle of the objective lens driving device 9) is adjusted.

  Next, as shown in FIG. 4, an adhesive is injected into the adhesive injection grooves 231, 232, and 233 formed on the front surface, the side walls 253 and 254, and the front wall 251 of the projection 26 of the apparatus frame 2, The objective lens driving device 9 is fixed in the recess 25. As a result, the objective lens driving device 9 is fixed in a state of slightly floating from the device frame 2.

(Main effects of this form)
When manufactured by such a method, the objective lens driving device 9 performs the tilt angle adjustment in a state where the entire objective lens driving device 9 is configured as one assembly, so that the objective lens driving device 9 is driven before the objective lens driving device 9 is mounted on the device frame 2. The characteristics of the device 9 can be grasped.

  Further, with the objective lens driving device 9 disposed in the recess 25, the front outer yoke 952 of the yoke 95 and the collimating lens 56 overlap to form the first overlapping portion 11, while the front outer yoke 952 of the yoke 95 The formed protrusions 991 and 992 overlap the apparatus frame 2 to form the second overlapping portion 12. Here, since the separation distance (dimension L1) in the first overlapping portion 11 is always longer than the separation distance (dimension L2) in the second overlapping portion 12, the inclination angle of the objective lens driving device 9 is adjusted. At this time, before the front outer yoke 952 of the yoke 95 interferes with the collimating lens 56, one of the protrusions 991 and 992 interferes with the apparatus frame 2. Therefore, the optical axis shift of the collimator lens 56 due to the interference between the front outer yoke 952 of the yoke 95 and the collimator lens 56 can be prevented.

  Furthermore, in this embodiment, the protrusions 991 and 992 formed on the front outer yoke 952 of the yoke 95 overlap the apparatus frame 2, but on the upper surface of the apparatus frame 2, the bottom or stepped portion of the hole 271 where the protrusions 991 and 992 overlap. Since 272 is one step lower from the highest position on the upper surface of the apparatus frame 2, the optical head can be used even when the protrusions 991 and 992 of the yoke 95 constitute the second overlapping portion 12 on the upper surface of the apparatus frame 2. The thinning of the device 1 is not hindered.

[Other embodiments]
In the above embodiment, the upper surface of the device frame 2 is used as the portion where the device frame 2 and the objective lens driving device 9 constitute the second overlapping portion 12, but it protrudes into the bottom 250 of the recess 25 formed in the device frame 2. A second overlapping portion may be formed between the protrusion and the bottom surface of the yoke. In the above embodiment, the collimator lens 56 has been described as an example of the optical element constituting the first overlapping portion 11 in the concave portion 25. However, the present invention is applied to the case where another optical element constitutes the first overlapping portion 11. May be applied.

It is the perspective view which looked at the optical head device to which the present invention is applied from the side from which light is emitted from an objective lens. FIG. 2 is a perspective view of a state where a main body cover and an actuator cover are removed from the optical head device shown in FIG. 1. It is a disassembled perspective view of the optical head apparatus shown in FIG. FIG. 2 is a perspective view of a state where a metal cover and an objective lens driving device are removed from the optical head device shown in FIG. 1. FIG. 2 is an explanatory diagram illustrating an overlapping portion between a yoke and a collimating lens and an overlapping portion between a yoke and an apparatus frame in the optical head device illustrated in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical head apparatus 2 Apparatus frame 9 Objective lens drive device 11 1st overlap part 12 2nd overlap part 25 Recessed part 30 1st laser light source apparatus 40 2nd laser light source apparatus 56 Collimating lens (optical element)
91 Objective lens 92 Lens holder 94 Holder support part 95 Yoke 271 Hole 272 Step part 991, 992 Projection part

Claims (5)

In an optical head device in which a light emitting element, an objective lens driving device that drives an objective lens in a tracking direction and / or a focusing direction, and an optical system that guides emitted light from the light emitting element to the objective lens are mounted on an apparatus frame. ,
When the optical axis direction of the objective lens is the vertical direction,
The device frame includes a concave portion in which the objective lens driving device is disposed, and a portion that overlaps the objective lens driving device in the vertical direction.
The optical system includes an optical element that is fixed at a position protruding inward from an inner peripheral wall in the recess and overlaps with a part of the objective lens driving device in the vertical direction,
Among the portions where the optical element and the objective lens driving device overlap in the vertical direction, the separation distance at the first overlapping portion with the shortest separation distance overlaps the device frame and the objective lens driving device in the vertical direction. An optical head device characterized in that, among the portions, the separation distance is longer than the separation distance in the second overlapping portion with the shortest distance. In claim 1,
The optical head device, wherein the second overlapping portion is positioned in the vicinity of the first overlapping portion. In claim 1 or 2,
In the objective lens driving device, the portion constituting the first overlapping portion and the second overlapping portion is a yoke used in a magnetic driving mechanism for driving the objective lens. apparatus. In claim 3,
A part of the yoke is positioned above the optical element to form the first overlapping part, and another part of the yoke is an optical axis up to an overlapping position in the vertical direction on the upper surface of the apparatus frame around the recess. An optical head device characterized in that a protrusion is formed on each of the left and right sides orthogonal to the direction, and the protrusion constitutes the second overlapping portion. A light emitting element, an objective lens driving device that drives the objective lens in a tracking direction and / or a focusing direction, and an optical system that guides emitted light from the light emitting element to the objective lens are mounted on the device frame, Is formed with a concave portion in which the objective lens driving device is disposed, and a portion overlapping with the objective lens driving device in the vertical direction is formed, and the optical system has a position protruding inward from an inner peripheral wall in the concave portion. In an optical head device manufacturing method including an optical element that is fixed to and overlaps with a part of the objective lens driving device in the vertical direction,
When the objective lens driving device is arranged in the concave portion, the separation distance at the first overlapping portion with the shortest separation distance among the portions where the optical element and the objective lens driving device overlap in the vertical direction is determined as the device. Among the portions where the frame and the objective lens driving device overlap in the vertical direction, the separation distance is set to be longer than the separation distance at the second overlapping portion with the shortest distance,
After fixing the optical system including the optical element to the device frame,
A method of manufacturing an optical head device, comprising: disposing the objective lens driving device in the concave portion; and adjusting the inclination of the objective lens driving device, and then fixing the objective lens driving device in the concave portion.

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