WO2001031652A1

WO2001031652A1 - Optical storage

Info

Publication number: WO2001031652A1
Application number: PCT/JP1999/005970
Authority: WO
Inventors: Miyozo Maeda
Original assignee: Fujitsu Limited
Priority date: 1999-10-28
Filing date: 1999-10-28
Publication date: 2001-05-03

Abstract

An optical storage comprises first and second parallel guide rails (52, 54), a carriage (44) for holding an optical head (46), a pair of first sliding bearings (110) fixed to the carriage (44) and adapted to slide on the first guide rail (52), and a second sliding bearing (112) fixed to the carriage (44) and adapted to slide on the second guide rail (54). The first sliding bearing (110) has a first bearing surface (110a), and the second sliding bearing (112) has second and third parallel bearing surfaces (112a, 112b). The second and third bearing surfaces (112a, 112b) of the second sliding bearing (112) are substantially parallel to the first bearing surface (110a) of the first sliding bearing (110).

Description

Description Optical storage device technology

The present invention relates generally to optical storage devices, and more particularly, to a light beam positioning mechanism of an optical disk device. Background technology

Optical discs have been in the spotlight as a core memory medium in the rapid development of multimedia in recent years, and are usually used in a cartridge case. . An optical disk cartridge is read into the optical disk device, and data is written to or read from the optical disk by an optical pickup (optical head).

Recent optical disc devices include a laser diode, a beam splitter that reflects and transmits a laser beam, and a photodetector that receives the reflected light from the optical disc in order to achieve miniaturization. It comprises a stationary optical assembly and a moving optical assembly including an actuator having a carriage and an objective lens attached to the carriage. The carriage is moved by the voice coil motor in the radial direction of the optical disc along a pair of rails.

The laser beam of write power emitted from the laser diode attached to the fixed optical assembly is collimated by the collimating lens, passes through the beam splitter, and is actuated. The light is reflected by the mirror for setting up the beam overnight, is focused on the optical disc by the objective lens, and data is written to the optical disc. On the other hand, data is read by irradiating an optical disc with a laser beam of read power. The reflected light from the optical disc is collimated by an objective lens, and then reflected by a beam splitter of a fixed optical assembly. The reflected light is detected by a photodetector and is reflected by an electric detector. Converted to a signal.

One night of the event is fixed to the carriage. The lens holder (actuator movable part) supported on the cantilever by a plurality of spring wires or plate panels on the actuator base. The lens holder has an objective lens, a focusing coil, and a plurality of tracking coils. In addition, the magnetic circuit constituting the Poiscoil Motor (VCM), which faces the focusing coil and the tracking coil, is fixed to the actuator or carrier.

In a conventional optical disc device, a carriage on which an optical head is mounted is moved in a radial direction of the optical disc along a pair of guide rails via a plurality of bearings ₍ guide rails). Includes fixed guide rails fixed to the base and pressurized guide rails pressurized by springs.Bearings are rotatably mounted on both sides of the carriage. However, these bearings move linearly by rolling the fixed guide rails and the pressurized guide rails, but move the carriages along the guide rails. The use of bearings for this purpose has the disadvantages that the weight of the carriage increases, the seek speed decreases, and the cost increases.

Therefore, a mechanism has recently been proposed in which a plain bearing is used instead of a bearing to move the carriage along a pair of guide rails. In other words, a pair of first sliding bearings are arranged on one guide rail with a predetermined separation, and a second sliding bearing is arranged on the other guide rail, and the carriage is supported by three sliding bearings. are doing. The second plain bearing is fixed to the carriage with a certain amount of play between it and the guide rail in order to absorb the parallelism error between the pair of guide rails.

In a conventional optical disc device that uses a sliding bearing, when the optical disc device is placed horizontally, the laser beam focused by the objective lens is adjusted so as to be perpendicular to the optical disc. However, when the optical disc device is placed vertically, that is, when the optical disc device is installed so that the surface formed by the pair of guide rails is perpendicular to the horizontal plane, the guide rail and the second guide rail are connected as described above. (2) Since there is some play between the slide bearing and the carriage, the carriage rotates around this guide rail by this play and focuses on the optical disc by the objective lens. This prevents the laser beam from being irradiated perpendicularly to the optical disc. Since the laser beam is designed to be focused on the recording surface of the optical disc by the objective lens through the transparent substrate of the optical disc, optical aberrations occur when the laser beam is tilted from the vertical direction with respect to the transparent substrate. As a result, predetermined performance cannot be exhibited. In other words, in the conventional optical disk device that uses a sliding bearing, the positional relationship between the optical disk and the objective lens changes depending on the installation state of the device. There is. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optical storage device which can overcome the above-mentioned drawbacks of the related art and exhibit a predetermined performance irrespective of the installation state of the device. DISCLOSURE OF THE INVENTION.

According to one aspect of the present invention, at least an optical storage device capable of reading information recorded on an optical storage medium, comprising: a base; a light source for emitting a light beam; and fixed to the base. A first guide rail; a second guide rail fixed to the base in parallel with the first guide rail; and a carriage movable along the first and second guide rails; An optical head mounted on the carriage, having an objective lens for condensing a light beam from a light source on the optical storage medium; and detecting a reproduction signal from reflected light from the optical storage medium. A photodetector; a first sliding bearing fixed to the carriage so as to be slidable along the first guide rail; and a carrier slidably along the second guide rail. The second sliding bearing fixed to the The first sliding bearing has a first bearing surface, the second sliding bearing has second and third bearing surfaces parallel to each other, and the second and third bearings are provided. An optical storage device is provided, wherein a surface is substantially parallel to the first bearing surface.

Preferably, the first sliding bearing has a fourth bearing surface, and a distance between the first bearing surface and the fourth bearing surface is substantially equal to a distance between the second bearing surface and the third bearing surface. More preferably, the first, second and third bearing surfaces are approximately 45 ° inclined with respect to the plane formed by the first and second guide rails.

According to another aspect of the present invention, at least an optical storage device capable of reading information recorded on an optical storage medium, comprising: a base; a light source for emitting a light beam; A first guide rail fixed to the base; a second guide rail fixed to the base in parallel with the first guide rail; and a carriage movable along the first and second guide rails; Having an objective lens for condensing a light beam from the light source on the optical storage medium, and an optical head mounted on the carriage; and from reflected light from the optical storage medium. A photodetector for detecting a reproduced signal; a first sliding bearing fixed to the carriage so as to be slidable along the first guide rail; and a slidable along the second guide rail. A second sliding bearing fixed to the carriage; the first sliding bearing has a substantially rectangular cross section and a first bearing surface defining one side of the rectangular cross section; The second sliding bearing is the second and third bearing surfaces parallel to each other Yes to have the second and third bearing surface optical memory device according to feature is provided that is parallel said first bearing surface and outline.

According to still another aspect of the present invention, at least an optical storage device capable of reading out information recorded on an optical storage medium, comprising: a base; a light source mounted on the base; A first guide rail; a second guide rail fixed to the base in parallel with the first guide rail; a carriage movable along the first and second guide rails; An optical head mounted on the carriage, the objective head condensing light from the optical storage medium onto the optical storage medium; and the base detecting a reproduction signal from reflected light from the optical storage medium. A first sliding bearing fixed to the carriage so as to be slidable along the first guide rail; a predetermined distance from the first sliding bearing; 1 Follow the guide rail A second sliding bearing slidably fixed to the carriage, and a third sliding bearing slidably fixed to the carriage along the second guide rail. Each of the first and second sliding bearings has a first bearing surface; the third sliding bearing has second and third bearing surfaces parallel to each other; An optical storage device is provided, wherein the third bearing surface is substantially parallel to the first bearing surface. According to still another aspect of the present invention, at least an optical storage device capable of reading out information recorded on an optical storage medium, comprising: a base; a light source mounted on the base; A first guide rail; a second guide rail fixed to the base in parallel with the first guide rail; and a first guide rail along the first and second guide rails. A movable carriage; an optical head mounted on the carriage, having an objective lens for condensing light from the light source on the optical storage medium; and the optical storage medium. A photodetector mounted on the base for detecting a reproduction signal from reflected light from a light source; a first sliding bearing slidably fixed to the carriage along the first guide rail; 1 a second sliding bearing fixed to the carriage so as to be slidable along the first guide rail at a predetermined distance from the sliding bearing; and slidable along the second guide rail. A third sliding bearing fixed to the carriage; and each of the first and second sliding bearings has a substantially square cross section and a first bearing surface defining one side of the square cross section. And the third sliding bearing is parallel to the second and third sliding bearings. And a third bearing surface, wherein the second and third bearing surfaces are substantially parallel to the first bearing surface. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an exploded perspective view of an optical disk device according to an embodiment of the present invention;

Figure 2 is a plan view of the base of the optical disk drive;

Figure 3 is a plan view of the moving optical assembly;

4A and 4B are perspective views of the holding panel for attaching the moving optical assembly to the base;

FIG. 5 is a bottom view of the read / write mechanism unit of the optical disk device of the present invention; FIG. 6 is a plan view of the optical disk device of the present invention;

Figure 7 is a perspective view of the moving optical assembly;

Figure 8 is a perspective view of the carriage showing the mounting state of the plain bearing;

FIG. 9 is a cross-sectional view of the carriage showing the relationship between the guide rail and the slide bearing according to the embodiment of the present invention;

Figure 10A is a cross-sectional view of the carriage when the device is placed vertically;

Fig. 10B is a cross-sectional view of the carriage when the top and bottom of Fig. 1 OA are reversed; Fig. 11 is a cross-sectional view of the carriage showing the relationship between the guide rail and the slide bearing of the comparative example. ;

Fig. 12 is a cross-sectional view of the carriage part when the comparative example of Fig. 11 is placed vertically. BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, an exploded perspective view of an optical disc device 2 according to an embodiment of the present invention is shown. The optical disk device 2 includes a load / eject mechanism unit 4 and a read / write mechanism unit 6. The load / eject mechanism unit 4 is attached to the chassis 8 having a potom plate 8a and a pair of side plates 8b, and the chassis 8 so as to be vertically movable with respect to the potom plate 8a of the chassis 8. Included cartridge holder 10. The cartridge holder 10 and the bottom plate 8a of the chassis 8 define an insertion slot 12 for inserting the optical disc cartridge from the direction of arrow C.

Guide grooves 14 are formed in the cartridge holder 10. The guide groove 14 is formed obliquely inward from the end of the inlet 12 of the cartridge, and is bent in the middle to be parallel to the longitudinal direction of the cartridge holder 10. A first slider 16 and a second slider 18 are slidably fitted in the guide grooves 14. Force—On one side of the cartridge holder 10, a first spring arm 20 and a second spring arm 22 are integrally formed with the cartridge holder 10 by a slit 23 formed continuously. Is formed. On the other hand, on the other side of the force storage holder 10, a third spring arm 24 is formed integrally with the force storage holder 10 by a slit 25. A bias magnetic field generator 26 is mounted on the cartridge holder 10.

On the bottom plate 8 a of the chassis 8, a cartridge identification sensor 28 that detects a write-protection state of the cartridge and a type of the cartridge is attached. An ejector 32 for ejecting the optical disc cartridge inserted into the cartridge holder 10 is mounted on the opposite side of the insertion opening 12 of the pot plate 8a. A lifting mechanism for the cartridge holder 10 is provided between the chassis 8 and the cartridge holder 10. When the optical disk cartridge is completely inserted into the cartridge holder 10, the The cartridge holder 10 is moved in the direction of the pot plate 8a of the chassis 8, and the optical disc cartridge is pressed against the pot plate 8a. In this state, the optical disk cartridge shutter Opens, and the exposed optical disc is checked at Spindlemo. The mechanism for raising and lowering the cartridge holder 10 is known, and will not be described further here.

The load / eject mechanism unit 4 is provided with a flexible printed circuit board (FPC) 30. The tip of the FPC 30 is branched into three, the first FPC 30a is connected to the bias magnetic field generator 26, and the second FPC 30b is connected to the ejector 32 The third FPC 30c is connected to the cartridge identification switch 28.

The read / write mechanism unit 6 includes a metallic base 34. The load / eject mechanism unit 4 is mounted on the base 34. The spindle motor 36 is fixed to the base 34. The base 34 further includes a moving optical assembly 38, a fixed optical assembly 40, and a printed wiring board 42. The moving optics assembly 38 includes a carriage 44 with an optical head 46. On the printed wiring board 42, a connector 48 for mounting to a printed wiring board (not shown) mounted on the upper part of the load / eject mechanism unit 4 is mounted. Reference numeral 50 denotes an FPC for transmitting a signal to the spindle motor 36 and a signal to the moving optical assembly 38.

Referring to FIG. 2, a plan view of the base 34 is shown. The base 34 is provided with a circular opening 34 A for inserting the spindle motor 36 and a substantially rectangular opening 34 B for receiving the moving optical assembly 38.

As shown in FIG. 3, the movable optical assembly 38 has the first and second guide rails 52 and 54 and the two center yokes 60 previously inserted into the carrier 44 so that the center yoke Assemble with the side yoke 58 fixed to 60. A permanent magnet 62 is fixed to the side yoke 58, and the side yoke 58, the center yoke 60, and the permanent magnet 62 constitute a magnetic circuit 56. The carriage 44 has a pair of coils (not shown) mounted thereon, and these coils are connected to the FPC 64. A voice coil motor (VCM) is formed by the magnetic circuit 56 and the coil, and the current is supplied to the coil through the FPC 64 to drive the VCM. It is guided by two guide rails 52 and 54. Referring again to FIG. 2, four rail holding recesses 6 6 for receiving both ends of the first and second guide rails 52, 54 of the moving optical assembly 38 are provided at both ends of the opening 34 B. And four housing portions 68 for receiving both ends of the side yoke 58 of the magnetic circuit 56 and the center yoke 60. The four storage sections 68 are provided with a reference surface 70 having high surface accuracy and formed by post-processing.

Both ends of the first and second guide rails 52, 54 of the movable optical assembly 38 assembled as shown in FIG. 3 and both ends of the joined side yoke 58 and center yoke 60 are The movable optical assembly 38 is placed on the rail holding recessed portion 66 and the accommodation portion 68 of the base 34, respectively, and the movable optical assembly 38 is mounted on the base 34. The moving optical assembly 38 is fixed to the base 34 using the fixing brackets (holding panels) 72 and 74 shown in FIGS. 4A and 4B. That is, screws are inserted into the holes 73, 75 of the fixing brackets 72, 74, and these screws are tightened into the screw holes provided on the base 34. FIG. 5 shows a state in which the movable optical assembly 38 is fixed to the base 34.

In FIG. 5, reference numeral 76 denotes a disk-shaped pedestal on which the spin Dormo overnight 36 is mounted on the back surface thereof.The pedestal 76 is attached to the base 34 at three locations around the disk. A recessed portion 78 is formed. The pedestal portion 76 is fixed to the base 34 by fastening the leg portions 78 to the base 34 with screws 82.

A fixed optical assembly 40 is mounted on the base 34. The fixed optical assembly 40 is composed of a laser diode 84, a collimating lens 86, a beam splitter 88, a wollaston prism 90, a condenser lens 92, a sensor 94, and a laser diode 84. Includes light intensity monitor unit 96. The fixed optical assembly 40 is mounted in an L-shaped groove 98 formed in the base 34. The L-shaped groove 98 has a first groove 98a provided on an extension of the movement direction of the carriage 44, and a second groove 98a provided in a direction orthogonal to the first groove 98a. Includes 2 grooves 9 8b. A beam splitter 88 is mounted at the intersection of the first groove 98a and the second groove 98b. A laser diode 84 and a collimating lens are provided in the first groove 98a. 86 is arranged. A Wollaston prism 90, a condenser lens 92, and a sensor 94 are arranged in the second groove 98b. In general, the base 34 of the lead / light mechanism unit 6 is formed by an aluminum die force, and the dimensional accuracy is low as it is. Therefore, in the present invention, as shown in FIG. 2, the mounting portion 100 (shown by hatching) of the collimating lens 86 in the first groove 98a and the inside of the second groove 98b The mounting portion 102 (indicated by hatching) of the condenser lens 92 is formed on a surface with good dimensional accuracy by post-processing the base 34. A collimating lens 86 and a condensing lens 92 are mounted on the surface having good dimensional accuracy. FIG. 6 is a plan view showing a state where the optical disc device 2 shown in FIG. 1 is assembled.

Referring to FIG. 7, a perspective view of the moving optical assembly 38 is shown in relation to the optical disk 108. An optical head 46 having an objective lens 47 is mounted on the carriage 44. A pair of coils 106 is fixed to both sides of the carriage 44. Each coil 106 is inserted into a gap defined by a center yoke 60 and a permanent magnet 62.

FIG. 8 is an enlarged view of the movable optical assembly 38 without the pair of magnetic circuits shown in FIG. 7, in which the carriage 44 is connected to the first guide rail 5 via the sliding bearings 110 and 112. The figure shows a state where it is supported by the second and second guide rails 54. The first guide rail 52 is fixed to the carriage 44 at a predetermined distance or inserted into a pair of first sliding bearings 110 formed integrally with the carriage 44. The second guide rail 54 is inserted into a second sliding bearing 112 fixed to the carriage 44 or formed integrally with the carriage 44. The first slide bearing 110 has a substantially square cross section, and the second slide bearing 112 has a substantially rectangular cross section. FIG. 9 is a schematic sectional view of the carriage guide mechanism according to the embodiment of the present invention. The optical disk 108 has a recording surface 108 a formed on a transparent substrate, and the laser beam emitted from the laser diode 84 is incorporated in the optical head 46. After being reflected by the beam rising mirror, the objective lens 47 focuses on the recording surface 108a of the optical disk 108. Carriage 4 4 is made of engineering 'plastic and has a pair of first plain bearings 110 with a substantially square cross section and a second plain bearing 1 1 2 with a substantially rectangular cross section. -Body molded. The first sliding bearing 110 has a first bearing surface 110a, a second bearing surface 110b, a third bearing surface 110c, and a fourth bearing surface 110d. The first bearing surface 110a is inclined approximately 45 ° with respect to a plane formed by the pair of guide rails 52, 54. The second plain bearing 111 has a first bearing surface 112a and a second bearing surface 112b opposite to the first bearing surface 112a. The first bearing surface 1 1 2a is substantially parallel to the first bearing surface 1 1 0a of the first sliding bearing 110, and is approximately 4 with respect to the plane formed by the pair of guide rails 52, 54. 5 ° inclined.

Since the first sliding bearing 110 has a substantially square cross section, the first bearing surface 111a and the third bearing surface 110c are substantially parallel, and the second bearing surface 110b And the fourth bearing surface 110d are substantially parallel. Since the cross section of the second sliding bearing 112 is substantially rectangular, the first bearing surface 112a and the second bearing surface 112b are substantially parallel. The distance between the first bearing surface 1 1 0a of the first sliding bearing 1 110 and the third bearing surface 110c and the first bearing surface 1 1 2a of the second sliding bearing 1 1 2 and the second bearing surface The gap with 1 1 2b is formed to be substantially equal.

In the carriage guide mechanism of the present embodiment, the first and second parallel bearing surfaces 1 1 2a and 1 1 2b of the second sliding bearing 1 1 2 It is important that they are substantially parallel to the plane 110a. Furthermore, the distance between the first bearing surface 110a of the first sliding bearing 110 and the third bearing surface 110c, the first bearing surface 112 of the second sliding bearing 112, and the second The spacing of the bearing surfaces 1 1 2b must be substantially equal. As long as these conditions are satisfied, the cross section of the first sliding bearing 110 is not limited to a square, and the cross section of the second sliding bearing 112 is not limited to a rectangle. For example, the cross section of the first sliding bearing 110 may be rhombic, and the cross section of the second sliding bearing 112 may be a parallelogram.

In the state shown in FIG. 9, the first guide rail 52 is in contact with the first and second bearing surfaces 110a and 110b of the first plain bearing 110, and the second guide rail 52 Numeral 54 is in contact with the first bearing surface 112a of the second plain bearing 111. In this state, the optical disc device is placed horizontally, and the optical disc 1 is set so that the optical axis 49 of the objective lens 47 is substantially perpendicular to the recording surface 108 a of the optical disc 108. 0 Rotate 8 Spindle motor 36 Rotary axis is adjusted. Fig. 1 OA shows the state when the optical disk device is placed vertically. Reference numeral 114 denotes a center of gravity of a carriage assembly 45 including a carriage 44, an objective lens 47, an actuating mechanism (not shown) for driving the objective lens 47, a beam setting mirror (not shown), and the like. Is shown. In this state, the first guide rail 52 comes into contact with the first bearing surface 11 Oa and the fourth bearing surface 11 Od of the first slide bearing 110 by the weight of the carriage assembly 45. I do. If the center of gravity 1 14 of the carriage assembly 45 is to the right of the plane formed by the pair of guide rails 52, 54, the carriage assembly 45 will rotate clockwise about the first guide rail 52. Then, the second guide rail 54 is pressed against the first bearing surface 112 a of the second sliding bearing 112.

Since the first bearing surface 1 1 Oa of the first sliding bearing 1 110 and the first bearing surface 1 1 2 a of the second sliding bearing 1 1 2 are parallel to each other, the carriage assembly 45 is connected to the objective lens 47. The optical axis 49 moves parallel to the bearing surfaces 110a and 112a while maintaining the vertical relationship with the storage surface 108a of the optical disk 108. Reference numeral 52 'indicates the position of the first guide rail 52 in the case of horizontal installation, and reference numeral 54' indicates the position of the second guide rail 54 in the case of horizontal installation.

In this case, the distance between the objective lens 47 and the optical disk 108 changes, but the laser beam is controlled by the focus following mechanism of the optical disk device, the so-called focusing support mechanism, and the laser beam is emitted. The misregistration is corrected so that the force is placed on the recording surface 108 of 08. As described above, the first sliding bearing 110 need not be square, but the first bearing surface 110a of the first sliding bearing 110 and the first bearing surface 1 of the second sliding bearing 112. It is important that 1 2a be parallel.

FIG. 10B shows the case where the vertical arrangement is opposite to that of FIG. 1OA, and the carriage assembly 45 is formed by the second and third bearing surfaces 1 10 b and 1 1 O c of the first sliding bearing 110. It is supported by the first guide rail 52 and is supported by the second guide rail 54 on the second bearing surface 112b of the second slide bearing 112. This is because the center of gravity 1 14 of the carriage assembly 45 is located on the left side of the plane formed by the pair of guide rails 52 and 54. The carriage assembly 45 has the first guide rail 52. This is because it rotates counterclockwise to the center and is pressed against the second bearing surface 1 1 b of the second guide rail 54. As described above, the first bearing surface 110a and the third bearing surface 110c of the first sliding bearing 110 are parallel, and furthermore, the first and second sliding bearings 111 of the second sliding bearing 112 are parallel to each other. The second bearing surfaces 1 1 2a and 1 1 2b are parallel to the first bearing surface 1 1 Oa of the first sliding bearing 110 and the first and third bearings of the first sliding bearing 110. Since the distance between the surfaces 11 O a and 11 O c and the distance between the first and second bearing surfaces 11 12 a and 11 b of the second sliding bearing 11 are equal, the light of the objective lens 47 is also The axis 49 and the recording surface 108a of the optical disk 108 can maintain the vertical relationship. As in Fig. 1 OA, reference numeral 52 'indicates the position of the first guide rail 52 when placed horizontally, and reference numeral 54' indicates the position of the second guide rail 54 when placed horizontally. .

FIG. 11 is similar to FIG. 9, but shows a comparative example in which the second sliding bearing 1 16 is not inclined with respect to the plane formed by the pair of guide rails 52, 54. The first sliding bearing 110 has the same structure and development as the embodiment of the present invention shown in FIG. FIG. 12 shows a case where this comparative example is placed vertically.

In FIG. 12, since the center of gravity 114 of the carriage assembly 45 is located on the right side of the plane formed by the pair of guide rails 52, 54, the carriage assembly 45 is formed by the first guide rail 52. , And is pressed against the second guide rail 54 by the first bearing surface 1 16a of the second slide bearing 1 16. The first guide rail 52 is in contact with the first bearing surface 111 Oa and the fourth bearing surface 111 Od of the first plain bearing 110, and is located at the position of the first guide rail 52 'when placed horizontally. It is out of comparison. Therefore, the objective lens 4 rotates with respect to the second guide rail 5 4 by the difference between the position of the first guide rail 52 in the vertical setting and the position of the first guide rail 52 ′ in the horizontal setting. The optical axis 49 of 7 is not perpendicular to the recording surface 108 a of the optical disk 108.

When the optical axis 49 of the objective lens 47 is displaced from the vertical direction with respect to the recording surface 108a of the optical disk 108, the beam spot formed on the recording surface 108a is displaced. As a result, the laser beam passing through the transparent substrate of the optical disk 108 will have an optical aberration, and the predetermined performance will not be exhibited. That is, the size of the beam spot in the circumferential direction affects the signal reproduction (signal level), and the size in the radial direction affects the level of tracking error. Therefore, the shape of the beam spot from a perfect circle When the state changes, a shift occurs between the optimum focus point for signal reproduction and the optimum focus point for detecting a tracking error. If the optimum focus point deviates, the signal level will be reduced and the reproduction performance will be reduced.

The objective lens used in the optical disc device is designed to focus a light beam on the recording surface of the optical disc through a transparent substrate having a predetermined thickness, so that a laser beam incident on the substrate is directed toward the substrate. tilts Te beam shape becomes elliptical in various would optical aberration occurs _c astigmatism, crescent-shaped around the main beam in coma sub peak can, peak intensity or unwanted signal reduction Cause. The spherical aberration has a circular peak around the main beam, which also causes the same problem as coma. When such optical aberrations occur, the beam spot diameter increases and the peak intensity of the optical beam decreases, so that the reproduction signal decreases during reproduction and a large recording power is required during recording.

However, in the present invention, as described above, the bearing surfaces 1 1 a and 1 1 2b of the second sliding bearing 1 1 2 are parallel to the first bearing surface 1 1 0 a of the first sliding bearing 1 1 0. Since the second sliding bearing 112 is formed as described above, such a problem does not occur. Therefore, beam quality is improved, and reproduction / recording performance is stabilized. Industrial applicability

In the present invention, as described in detail above, the bearing surfaces of the second sliding bearing are formed parallel to each other, and the first and second sliding bearings are arranged so as to be parallel to the bearing surface of the first sliding bearing. Irrespective of how the optical disk device is placed, that is, regardless of whether it is placed horizontally or vertically, the optical axis of the objective lens can always be kept perpendicular to the recording surface of the optical disk. Preferably, the distance between the opposing bearing surfaces of the first sliding bearing and the distance between the opposing bearing surfaces of the second sliding bearing are formed to be equal. In this case, the optical axis of the objective lens can always be kept perpendicular to the recording surface of the optical disk even in the case of two types of vertical placement with the top and bottom reversed.

ADVANTAGE OF THE INVENTION According to this invention, the stable performance is obtained even if the arrangement | positioning state of an apparatus changes, and the reliability of an apparatus can be improved.

Claims

Scope of claim

1. An optical storage device capable of reading information recorded on at least an optical storage medium,

With the base;

A light source for emitting a light beam;

A first guide rail fixed to the base;

A second guide rail fixed to the base in parallel with the first guide rail; a carriage movable along the first and second guide rails;

An optical head mounted on the carriage, having an objective lens for condensing a light beam from the light source on the optical storage medium;

A photodetector for detecting a reproduction signal from reflected light from the optical storage medium;

A second rail fixed to the carriage so as to slide along the first guide rail.

1 sliding bearing;

A second sliding bearing fixed to the carriage so as to slide along the second guide rail;

The first sliding bearing has a first bearing surface, the second sliding bearing has second and third bearing surfaces parallel to each other,

The optical storage device, wherein the second and third bearing surfaces are substantially parallel to the first bearing surface.

2. The first sliding bearing has a fourth bearing surface parallel to the first bearing surface, and the distance between the first and fourth bearing surfaces and the distance between the second and third bearing surfaces is substantially equal. The optical storage device according to claim 1, wherein:

3. The optical storage device according to claim 1, wherein each of the first to third bearing surfaces is inclined approximately 45 ° with respect to a plane formed by the first and second guide rails.

4. An optical storage device capable of reading information recorded on at least an optical storage medium,

With the base; A light source for emitting a light beam;

A first guide rail fixed to the base;

A second guide rail fixed to the base in parallel with the first guide rail; and a carriage movable along the first and second guide rails;

A second rail fixed to the carriage so as to slide along the first guide rail.

1 sliding bearing;

A second sliding bearing fixed to the carriage slidably along the second guide rail;

The first slide bearing has a substantially rectangular cross section and a first bearing surface that defines one side of the square cross section, and the second slide bearing has second and third bearing surfaces parallel to each other. And

5. The first sliding bearing has a fourth bearing surface parallel to the first bearing surface, and a distance between the first bearing surface and the fourth bearing surface is a distance between the second bearing surface and the third bearing surface. 5. The optical storage device according to claim 4, wherein the distance is substantially equal to the distance between the two.

6. The optical storage device according to claim 4, wherein the first bearing surface is substantially 45 ° inclined with respect to a plane formed by the first and second guide rails.

7. An optical storage device capable of reading out information recorded on at least an optical storage medium,

With the base;

A light source mounted on the base;

A first guide rail fixed to the base;

An objective lens for condensing light from the light source on the optical storage medium; An optical head mounted on the ridge;

A photodetector mounted on the base for detecting a reproduction signal from light reflected from the optical storage medium;

A first sliding bearing fixed to the carriage so as to be slidable along the first guide rail;

A second sliding bearing fixed to the carriage so as to be slidable along the first guide rail at a predetermined distance from the first sliding bearing;

A third sliding bearing fixed to the carriage slidably along the second guide rail;

Each of the first and second slide bearings has a first bearing surface, the third slide bearing has second and third bearing surfaces parallel to each other,

8. An optical storage device capable of reading out information recorded on at least an optical storage medium,

With the base;

A light source mounted on the base;

A first guide rail fixed to the base;

An optical head having an objective lens for condensing light from the light source on the optical storage medium, and an optical head mounted on the carriage;

A second rail fixed to the carriage so as to slide along the second guide rail. Equipped with three sliding bearings;

Each of the first and second slide bearings has a substantially square cross section and a first bearing surface that defines one side of the square cross section, and the third slide bearing is a second and third bearing parallel to each other. Surface