Optical disc apparatus for optically processing information

Abstract: In an optical disk apparatus, an objective lens 29 is suspended movably along its optical axis by diaphragm structures and mounted on a carrier (6). The carrier (6) is movably mounted on guide rails (4) by a pair of support structures (8). In each of the support structures (8), two pair of rollers (12) are rotatably fixed on first and second blocks (13), respectively, which are fixed to both ends of a leaf spring (14). The center portion of the leaf spring (14) is fixed to the side surface of the carrier (6) and gaps are provided between both ends of the leaf spring (14) and the side surface of the carrier (6).

Description: The present invention relates generally to an optical disk apparatus for optically processing information, and more particularly to an optical disk apparatus capable of optically reading/writing information at high speed. An optical disk apparatus for optically recording information on an optical information recording medium such as an optical disk or an optical-magneto disk, or optically reproducing information from the optical information recording medium has a much greater memory capacity than a magnetic disk apparatus, etc. Thus, the optical disk apparatus will be widely used as an information recording/reproducing apparatus in near future. In the optical disk apparatus, a light beam emitted from a light source is converged on a recording surface of an optical disk through an an objective lens. When optical information is reproduced, a light beam having a predetermined intensity is modulated on the recording surface of the optical disk and reflected from the recording surface. The reflected beam is detected to reproduce the optical information. When information is recorded, the light beam emitted from the light source is modulated to write optical information on the optical disk. In this optical disk apparatus, the objective lens is supported movably along the optical axis for focus control, and moved in the focusing direction. In addition, the objective lens is supported movably along the surface of the optical disk in a direction perpendicular to the optical axis for information access and tracking control, and is moved in a radial direction, i.e. tracking direction. Specifically, the objective lens is kept in the focused state, and the light beam is converged on the recording surface of the optical disk so that a minimum beam spot is formed on the recording surface of the optical disk. Further, the objective lens is kept in the tracking state, thereby enabling a light beam to trace a desired track on the optical disk, e.g. a tracking guide or a tracking guide sequence. The objective lens is kept in the focused state or in the tracking state, so that the light beam is intensity-modulated, thereby recording information on the surface of the optical disk, or the information is reproduced by detecting the beam reflected from the optical disk through the objective lens. For example, Japanese Laid-Open Patent disclosure No. 63-17137 discloses a conventional optical disk apparatus, which is shown in Figs. 1 to 4. In the optical disk apparatus, a frame 101 is provided within a housing of the optical disk apparatus. The housing is fixed by means of four leg members 102 and 103. The frame 101 extends in the Y-direction. A pair of cylindrical steel support rails 105 and 106 are distanced in the Z-direction and fixed at both ends of the frame 101. An elongated pick-up body 107 extending in the Z-direction are arranged between the support rails 105 and 106 and supported movably by the rails 105 and 106. One side end of the pick-up body 107 is provided with two steel rollers 108 which roll over the support rail 105, and the other side end of the pick-up body 107 are provided with two pairs of steel rollers 109. One pair of the two pairs of rollers 109 are distanced from the other in a direction in which the pick-up body 107 moves. The rollers 109 are supported by the other support rail 106. As seen from Fig. 4, the pick-up body 107 is supported by the support rails 105 and 106 at three support points where the rollers 108 and 109 are provided. As shown in Fig. 1, each roller 108 provided at one side end of the pick-up body 107 is attached at a free end portion of a lever 112. The lever 112 is attached on the pick-up body via a pin 111 and is swingable in the direction of arrow R. The direction of arrow R is perpendicular to the direction in which the pick-up body moves (i.e. Y-direction and a direction opposite to Y-direction). A spring member 113 is provided to press the roller 108 on the support rail 105. Since the rollers 108 (situated at one of the three support points) are pressed on the rail 105, the other rollers 109 (situated at the other support points) are also pressed on the support rail 106 by reaction force. As shown in Figs. 1 and 2, the frame 101 is provided with a pair of longitudinal magnetic circuits 120, each comprising a longitudinal magnet 116 and longitudinal yokes 117 and 118 engaged with one another and all extending in the direction in which the pick-up body 107 extends (Y-direction and a direction opposite thereto). As shown in Fig. 2, a pair of drive coils 121 are attached to the pick-up body 107. The coils 121 extend in parallel to the direction in which the pick-up body 107 moves. The magnetic circuits 120 generate magnetic fluxes crossing the drive coils and constitute, along with the drive coils, a linear motor for applying a moving force to a moving optical system including the pickup body 107. However, the optical disk apparatus shown in Figs. 1 to 4 have the following problems. Since the rollers 108 and rollers 109 are arranged outside the drive coils 121, mass distribution increases at both end portions of the pick-up body 107. As a result, the resonance frequency of the pick-up body 107 decreases, and wide-band control operation necessary for high-speed access becomes unstable. In order to solve this problem, it is possible to set the driving center at the node of oscillation; however, in order to set the driving center at the node, it is necessary to further increase the mass at both ends of the pick-up body. Consequently, the driving acceleration speed lowers. As shown in Fig. 3, an actuator for finely moving an objective lens 158 in a focusing direction (arrow F) and a tracking direction (arrow T) is mounted on the pick-up body 107. Thus, when the pick-up body 107 is moved at high speed for access, it is necessary to apply a force in the T-direction to cancel the acceleration of the pick-up body 107, thereby preventing the objective lens 158 from vibrating. This increases power consumption of the entire apparatus. The pins for rotatably supporting the rollers are firmly attached on the metallic pick-up body 107. The four pins for the rollers 109 and one pin for one of the rollers 108 are firmly fixed on the pick-up body 107 and allow freedom of rotation. The other roller 108 for applying pre-load is pressed on the support rail 105. Thus, the angle of inclination of the pick-up body 107 is definitely determined by the precision of attachment of the rollers excluding the roller 108 for pre-pressing and by the precision of attachment of the support rails 105 and 106, and there is no room for adjustment. Since the optical disk apparatus is so constructed that the vibration occurring in the pick-up body cannot be damped between the rollers and the pick-up body 107, abnormal vibration may occur and it is difficult to achieve stable control operation. Such an apparatus is disclosed in DE-A-3 839 708, which reflects the preamble of claim 1. The object of the present invention is to provide an optical disk apparatus capable of accessing a target track quickly, and carrying out high-precision stable focus control and tracking control. According to the present invention, there is provided an optical disk read/write apparatus as defined in appended independent claim 1. The elastic body for supporting the roller unit may be constituted by a plate spring element having a plane substantially parallel to the direction in which the movable optical body moves. Alternatively, the elastic body for supporting the roller unit may be constituted by a parallel spring element having a plane substantially parallel to the direction in which the movable optical body moves. The roller unit may comprise a resin block, steel pins and steel rollers, and the plate spring element or parallel spring element, block and pins may be integrally formed by injection molding. Alternatively, the roller unit may comprise a resin block, steel pins and steel rollers, the plate spring element may be formed of the same resin as the block, and the plate spring, block and pins may be integrally formed by injection molding. Gaps of less than 1 mm may be provided between the roller block and the pick-up body of the movable optical body. After the support unit comprising the roller unit and the elastic body is fixed to the pick-up body of the movable optical body, at least two of the gaps may be filled with a thermosetting, room temperature setting, or photo-setting adhesive or filler. Alternatively, gaps of less than 1 mm may be provided between the roller block and the pick-up body of the movable optical body, and, after the support unit comprising the roller unit and the elastic body is fixed to the pick-up body of the movable optical body, at least one of the gaps may be filled with a visco-elastic agent such as silicone gel. The plate spring and the pick-up body of the movable optical body may be formed of a metallic material, and the pick-up body of the movable optical body and the plate spring may be fixed by welding means such as electric spot welding or laser spot welding. Alternatively, the plate spring may be formed of a metallic material, the metallic elements of the pick-up body may be formed of out-sert or insert resin, the metallic portion may be exposed at the connecting portion with the plate spring, and the carriage and the plate spring may be fixed by means of welding means such as electric spot welding or laser spot welding. The plate spring element of the support unit may be fixed between the pick-up body of the optical movable body and the coil for driving the movable optical body, the roller unit may be situated outside the coil end, and the yoke penetrating the coil may function as the roller guide shaft. Alternatively, the plate spring element of the support unit may be fixed between the pick-up body of the movable optical body and the coil for driving the movable optical body, the roller unit may be situated outside the coil end, and the yoke penetrating the coil may be provided with a V-groove in which the roller guide shaft is to be fixed. In an optical disk apparatus wherein an objective lens is moved in the radial direction of an optical disk, a movable optical body on which the objective lens is mounted is constituted such that the movable optical body is supported by four roller units, each roller unit comprises two rollers, two pins and a block, each unit is supported at one end of an elastic body, and the other end of each elastic body is fixed to the pick-up body of the movable optical body. Thus, the movable optical body is engaged with a shaft via the elastic body and high-frequency vibration of the shaft is not transmitted to the movable optical body. Therefore, stable control operation can be attained. In an optical disk apparatus wherein an objective lens is moved in the radial direction of an optical disk, a movable optical body on which the objective lens is mounted is constituted such that the movable optical body is supported by four roller units, each roller unit comprises two rollers, two pins and a block, the roller unit is fixed at both ends of an elastic body and a center portion of the elastic body is fixed to the pick-up body of the movable optical body. Thus, the movable optical body is engaged with a shaft via the elastic body and high-frequency vibration of the shaft is not transmitted to the movable optical body. Therefore, stable control operation can be attained. In addition, since the elastic body is coupled to the carriage at the center portion of the elastic body, a stress does not concentrate at the coupling portion, and the coupling is firm. Since the elastic body for supporting the roller unit is constituted by a plate spring element having a plane substantially parallel to the direction in which the movable optical body moves, the rigidity in the direction of movement is high and abnormal vibration hardly occurs at the time of high-speed access. Alternatively, since the elastic body for supporting the roller unit is constituted by a parallel plate spring element having a plane substantially parallel to the direction in which the movable optical body moves, the rigidity in the direction of movement is high and abnormal vibration hardly occurs at the time of high-speed access. In addition, even when the plate spring is deformed to apply a pre-load to the roller unit, the angular relationship between the roller shaft and the shaft is kept constant. Thus, the rolling resistance due to an angle variation does not increase, and smooth movement is attained. Since the roller unit comprises a resin block, steel pins and steel rollers, and the plate spring element or parallel spring element, block and pins are integrally formed by injection molding, the relative position and relative angle of each pin can be kept constant. Thus, the rolling resistance due to a positional displacement or an angle variation does not increase, and smooth movement is attained. The roller unit comprises a resin block, steel pins and steel rollers, the plate spring element is formed of the same resin as the resin block, and the plate spring element, block and pins are integrally formed by injection molding. Thus, the relative position and relative angle of each pin can be kept constant, the rolling resistance due to a positional displacement or an angle variation does not increase, and smooth movement is attained. The gaps of less than 1 mm are provided between the roller block and the pick-up body of the movable optical body and, after the support unit comprising the roller unit and the elastic body is fixed to the pick-up body of the movable optical body, at least two of the gaps are filled with a thermosetting, room temperature setting, or photo-setting adhesive or filler. Thus, after assembly, the inclination angle of the movable optical body is adjusted by utilizing the elasticity of the elastic body, thereby setting the optical axis at an optimal angle. Thereafter, at least two of the gaps are filled with a thermosetting, room temperature setting, or photo-setting adhesive or filler, and the desired state of the optical axis can be maintained. The gaps of less than 1 mm are provided between the roller block and the pick-up body of the movable optical body, and, after the support unit comprising the roller unit and the elastic body is fixed to the pick-up body of the movable optical body, at least one of the gaps is filled with a visco-elastic agent such as silicone gel. Thus, the vibration of the movable optical body can effectively be damped, and high-precision control operation can be carried out. The plate spring and the pick-up body of the movable optical body are formed of a metallic material, and the pick-up body of the movable optical body and the plate spring are fixed by caulking or welding means such as electric spot welding or laser spot welding. Thus, the movable optical body can be firmly coupled to the pick-up body. Alternatively, the plate spring is formed of a metallic material, the metallic elements of the pick-up body are formed of out-sert or insert resin, the metallic portion is exposed at the connecting portion with the plate spring, and the carriage and the plate spring are fixed by means of caulking or welding means such as electric spot welding or laser spot welding. Thus, the movable optical body and the pick-up body can be firmly coupled, and the insulating property of the coil can be enhanced. The plate spring element of the support unit is fixed between the pick-up body of the optical movable body and the coil for driving the movable optical body, the roller unit is situated outside the coil end, and the yoke penetrating the coil functions as the roller guide shaft. Thus, the support point of the movable optical body can be approached to the drive point for driving the movable optical body, and the occurrence of abnormal resonance can be prevented. The plate spring element of the support unit is fixed between the movable optical body and the coil for driving the movable optical body, the roller unit is situated outside the coil end, and the yoke penetrating the coil is provided with a V-groove in which the roller guide shaft is to be fixed. Thus, the support point of the movable optical body can be approached to the drive point for driving the movable optical body, and the occurrence of abnormal resonance can be prevented. In addition, the contact layer between the V-groove and the guide shaft can effectively damp the vibration of the shaft, and high-precision control operation can be carried out. Since a plurality of diaphragm springs are coupled by diffusion coupling to constitute the diaphragm unit, an objective lens support system with high rigidity in radial direction can be obtained. This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is a plan view showing schematically a conventional optical disk apparatus; Fig. 2 is a cross-sectional view taken along the Z-axis in Fig. 1; Fig. 3 is a cross-sectional view taken along the Y-axis in Fig. 1; Fig. 4 is a plan view of the optical disk apparatus of Fig. 1, with part of the pick-up body removed; Fig. 5 is a plan view showing an optical disk apparatus according to embodiment 1 of the present invention; Fig. 6 is a cross-sectional view taken along line A-A in Fig. 5; Fig. 7 is a plan view showing schematically a movable optical body shown in Fig. 1; Fig. 8 is a perspective view showing a support unit for the movable optical body shown in Fig. 7; Fig. 9 is an exploded perspective view of the movable optical body shown in Fig. 7; Fig. 10 is a perspective view of the assemble movable optical body shown in Fig. 7; Fig. 11 is a plan view showing the movable optical body assembled and adjusted with respect to inclination; Fig. 12 is a perspective view for illustrating a support unit for an optical disk apparatus according to an another embodiment of the invention; Fig. 13 is a perspective view for illustrating a support unit for an optical disk apparatus according to a still another embodiment of the invention; Fig. 14 is a perspective view for illustrating a support unit for an optical disk apparatus according to a yet another embodiment of the invention; Fig. 15 is a cross-sectional view showing a pick-up body of an optical disk apparatus according to a further embodiment of the invention; and Fig. 16 is a cross-sectional view for illustrating a yoke and a guide shaft of an optical disk apparatus according to a still further embodiment of the invention. Embodiments of the optical disk apparatus according to the present invention will now be described with reference to the accompanying drawings. Embodiment 1 Fig. 5 is a plan view showing an optical disk apparatus according to a first embodiment of the present invention, and Fig. 6 is a cross-sectional view taken along line A-A in Fig. 5. As shown in Figs. 5 and 6, a frame 1 is provided within a housing 2 of the optical disk apparatus. The frame 1 is fixed within the housing such that four leg members 3 arranged within the housing 2 are screwed at four corners of the frame 1. A pair of cylindrical magnetic support rails or guide shafts 4, which extend in parallel in the Y-direction with a distance in the Z-direction, are fixed to the frame 1. A movable optical body or carriage unit 5, as shown in Fig. 7, is movably supported by the support rails or guide shafts 4. The movable optical body 5 comprises, as shown in Fig. 7, a focus unit 7 fixed on the pick-up body 6 to support an objective lens 29 movably in the direction of the optical axis or X-direction, two pairs of support units 8 fixed to the pick-up unit 6 for supporting the pick-up unit 6 on the support rails 4, two radial coils 9 for generating a driving force for driving the pick-up body 6, and a mirror unit 10 fixed to the pick-up unit 6 and situated along the light path defined within the pick-up body 6 for directing a light beam to the objective lens and directing the light beam reflected from a recording surface 39 of the optical disk to a detection optical system. In the support unit 8, as shown in Fig. 8, two pairs of steel rollers 11, which roll over the support rails or guide shafts 4, are rotatably supported on two pairs of pins 12. Each pair of pins 12 are fixed on a roller block 13 so that the center axes thereof cross each other. The two roller blocks 13 are coupled by a plate spring 14. The roller blocks 13 are made of a high-rigidity engineering plastic material, in such a manner that four pins 12 and plate spring 14 are fixed in a mold and the plastic material is injected in the mold. As is shown in Fig. 9, the pick-up body 6 is formed symmetrical with respect to an XY-plane. In addition, the external appearance of the pick-up body 6 is substantially symmetrical with respect to an XZ-plane. Both side portions of the pick-up body 6 along the axis of Z-direction are provided with cylindrical curved faces 15 for receiving cylindrical radial coils 9. The radial coils 9 are attached to the curved faces 15. Grooves 16 extending in Y-direction are provided on the inside of the curved faces 15. Shallower grooves 17 are formed at middle parts of the grooves 16. The pick-up body 6 is fixed to support units 8 by means of adhesion, welding, screwing or caulking, while center portions 21 of plate springs 14 of support units 8 are situated in the grooves 17 at the side faces of pick-up body 6. In order to perform welding, it is, at least, necessary that the plate springs 14 and grooves 17 are made of a metal. In this case, the plate springs 14 and grooves 17 are coupled by means of electric spot welding or laser spot welding. The radial coils 9 are fixed to the pick-up body 6 by abutting the coils 9 upon the curved faces 15 of the body 6 and adhering the coils 9 to the curved faces 15, as shown in Fig. 9. When the support units 8 and radial coils 9 are coupled to the pick-up body 6, the movable body 5 in which the pick-up unit 6, support units 8 and radial coils 9 are integrally assembled is formed, as shown in Fig. 10. Each plate spring 14 of support unit 8 is clamped between the pick-up body 6 and the associated radial coil 9. Since stepped portions are provided between the groove 16 and shallower groove 17, a clearance is produced between the plate spring 14 and the bottom wall of the groove 16 and the plate spring 14 is deformably fixed on the pick-up body 6. Accordingly, the rollers 11 and roller blocks 13 are supported by the movable optical body 5 so as to be slightly deformable in Z-direction by virtue of elasticity of the plate spring 14. When the rollers 11 are put in contact with the rails or guide shafts 4, gaps 23 are produced between the rear faces of the roller blocks 13 and the side faces of the support unit stoppers 18. As is shown in Fig. 11, two gaps 23 on one side are filled with a coagulating agent 24 such as an adhesive, and the other two gaps 23 are filled with an elastic material 25 such as silicone gel. The magnetic support rails or guide shafts 4 are made of a magnetic permeable material, and function as yokes of a magnetic circuit 26 for applying magnetic fields to the radial coils 9. The magnetic support rails 4 penetrate the coils 9 such that slight gaps are provided between the inner surfaces of the coils 9 and the outer surfaces of the rails 4. The support rails 4 abut on the rollers 11 of the support unit 8. As is shown in Figs. 5 and 6, a pair of substantially U-shaped back yokes 27 are arranged on the frame 1 so as to be substantially symmetrical with respect to XY-plane. The back yokes 27 are fixed on the frame 1 by means of screws. A magnet 28 is attached to the inside surface of each back yoke 27. The magnet 28 extends in Y-direction, facing the associated magnetic support 4 with a gap. Both end portions of each support rail or guide shaft 4 are coupled to mutually facing ends of the associated bent back yoke 27. Each of the two magnetic circuits 26 comprises the support rail or guide shaft 4, back yoke 27 coupled to both ends of the rail 4, and magnet 28 fixed to the back yoke 27. The magnetic circuit 26 generates a magnetic flux interlinked with the radial coil 9. The magnetic circuit 26 and radial coil 9 constitute a linear motor serving as a moving force applying means for exerting a moving force to the movable optical body 5 including the pick-up body 6. The following effects and advantages can be obtained. In the access mechanism for moving the objective lens 29 in the radial direction of the optical disk, the movable optical body 5 is supported by the support units 8 having two plate springs 14. As a result, the movable optical body 5 is brought into contact with the magnetic support rails or guide shafts 4 via elastic members. Accordingly, high-frequency vibration of the magnetic support rails or guide shafts 4 is not transmitted to the movable optical body 5, and stable control operation can be carried out. In addition, since the connecting portions between the support units 8 and the pick-up body 6 are situated at center parts of the plate springs 14 of the support units, deformation of each plate spring 14 due to pressing force occurs symmetrically and a stress does not concentrate on the connecting portions. Thus, connection at the connecting portions is firm. The elastic material for supporting the roller block 13 is constituted by a plate spring element having a plane substantially parallel to Y-direction in which the movable optical body moves. Thus, the elastic material has high elasticity in Z-direction but is hard in the direction in which the optical body moves. The pin block 13 is formed of resin and is injection-molded integrally with the metal plate springs 14 and pins 12. Thus, the relative position and angle of each roller pin can be kept constant, the roll resistance is not increased due to the positional displacement or angle displacement, and smooth movement is attained. The gaps 23 of less than 1 mm are provided between the support unit stoppers 18 and the roller blocks 13 of the pick-up body 6. After the support units 8 are fixed to the pick-up body 6, at least two of the four gaps 23 are filled with coagulating agent. It is thus possible to utilize the elasticity of the plate springs 14 after assembly, adjust the angle of the pick-up body 6 to set the optical axis at an optimal angle, and then fill adhesive to at least two gaps to maintain the optimal condition. The gaps 13 of less than 1 mm are provided between the roller blocks 13 and the support unit stoppers 18. After the support units 8 are fixed to the pick-up body 6, at least one of the gaps is filled with visco-elastic agent 25 such as silicone. Therefore, the vibration of the pick-up body 6 can effectively be damped, and high precision control operation can be carried out. The plate springs 14 and pick-up body 6 are formed of a metallic material and these are fixed by means of caulking or welding means such as electric spot welding or laser spot welding. Thus, the springs 14 can be firmly fixed to the pick-up body 6. The plate spring element of the support unit is fixed between the pick-up body 6 and the radial coil 9 for driving the pick-up body 6, the rollers are situated outside the end portions of the coil 9, and the yoke penetrating the coil functions also as the guide shaft for the roller. Thus, the support points of the pick-up body 6 can be made closer to the drive points of the pick-up body 6, and abnormal resonance can be prevented. The flexible guide 49 extending in Y-direction at least to the center of rotation of rollers 11 is attached to the Y-axial end face of the pick-up body 6, and the flexible guide 49 is provided with a flexible print board bent in a substantially U-shape. Therefore, the flexible print board does not contact with the rollers 11 at any point, and a stable, long life of the flexible print board can be obtained. Embodiment 2 According to the optical disk apparatus of the first embodiment, the support unit is constituted such that two rollers are provided at both ends of the plate spring. However, as shown in Fig. 12, it is possible to substitute two support units 8 for the support unit 8. In each support unit 8, two rollers are provided only at one end of the plate spring. In the optical disk apparatus with the above structure, even if the plate spring 14 has a curvature, the plate spring 14, roller block 13 and pins 12 can be injection-molded integrally with high precision. Thus, it is easy to obtain such a structure that the plate spring is stretched in a flat shape and a pre-load is applied, in the state that the rollers 11 are put in contact with magnetic support rails or guide shafts 4. It is possible to enhance the precision of angle setting for the pins and magnetic support rails 4 (guide shafts). Therefore, there can be obtained a stable product in which no variation exists in rolling frictional resistance between the rollers 11 and the magnetic support rails (guide shafts) due to solid differences. Embodiment 3 According to the optical disk apparatus of the first embodiment, the support unit is constituted such that two rollers are provided at both ends of the plate spring. However, as shown in Fig. 13, it is possible to use a plate spring comprising a plurality of parallel plate springs and attaching a fixed block 52 at a middle part of the plate spring. The support units 8 may be replaced by two support units 53 each comprising roller blocks 13 at both ends, fixed block 52 and plate springs 51. The optical disk apparatus according to the third embodiment of the present invention has the same advantages as the apparatus according to the first embodiment. The third embodiment has the following effect. The rollers 11 are elastically supported by the parallel plate spring mechanism. Thus, even if the plate spring is deformed to apply a pre-load, the relationship in angle between the roller shafts and the magnetic support rails (guide shafts) can be kept unchanged. Therefore, the rolling resistance does not increase due to the departure from the predetermined angles of the roller shafts and magnetic support rails (guide shafts), and smooth movement can be attained. Furthermore, when the roller block is formed of resin and the block, pins, rollers and parallel plate spring elements are injection-molded integrally, the precision of the relative angle and relative position of the pins can be further enhanced, and the rolling resistance does not increase due to the departure from the predetermined position and angles, and smooth movement can be attained. Embodiment 4 In the support unit 8 shown in Fig. 8, two roller blocks 13 are fixed at both ends of the plate spring 14. A pair of steel rollers 11 are rotatably fixed to each roller block 13, and the rollers 11 of each pair are supported movably by the plate spring 14. However, as shown in Fig. 14, it is possible that the respective rollers 11 are supported by the plate spring 14 so as to be movable independently. Specifically, as shown in Fig. 14, the plate spring 14 has notches 14C extending inwards from both ends in the longitudinal direction. Each end portion of the plate spring 14 is separated into a pair of tongues 14a and 14B which are deformable independently. Roller block segments 13A and 13B are fixed to the tongues 14A and 14B. Like the support unit 8 shown in Fig. 8, pins 12 are fixed to the roller block segments 13A and 13B, and steel rollers 11 are rotatably attached to the pins 12. The paired pins 12 are fixed to the paired roller block segments 13A and 13B such that the center axes of the pins 12 cross each other in the non-deformed state of the plate spring 14, like the support unit 8 shown in Fig. 8. The four roller block segments 13A and 13B are coupled by the plate spring 14. The four roller block segments 13A and 13B are made of a high-rigidity engineering plastic material, like the support unit 8 shown in Fig. 8. The block segments 13A and 13B are formed by injecting plastic material into a mold while four pins 12 and plate spring 14 are fixed in the mold. In the support unit 8 shown in Fig. 14, when the rollers 11 are mounted on the support rails or guide shafts 4, four gaps 23 are produced between the rear faces of the roller block segments 13A and 13B and the support unit stoppers 18, as shown in Fig. 7. The four gaps of one of the support units 8 are filled with a coagulating agent 24 such as an adhesive, and the four gaps of the other support units 8 are filled with a visco-elastic material 25 such as silicone gel. According to the support unit 8 shown in Fig. 19, the four gaps 23 are provided between the rear faces of the roller block segments 13A and 13B and the side faces of the support unit stoppers 18. Since the size of each gap is adjustable, the degree of freedom of adjustment is high at the time of assembling the optical disk apparatus, and fine adjustment can be ensured. Embodiment 5 In the first embodiment, the pick-up body 6 is formed of a single material; however, as shown in Fig. 15, it is possible to integrally form a pick-up body 56 of metal material 54 and resin material 55 by means of injection molding. The metallic contact portions of the body 56 with the plate springs are exposed. The fifth embodiment has the following advantage, in addition to the advantages obtainable with the first embodiment. Where the connection portion between the support member and the pick-up body is made of a metal, the support unit and the pick-up body can be coupled by means of welding such as electric spot welding or laser spot welding. Thus, the support unit and the pick-up body 6 can be coupled firmly, and the insulation effect of the coil can be enhanced. Embodiment 6 In the first embodiment, the magnetic support rail (guide shaft) 4 is used as part of the yoke of the magnetic circuit; however, as shown in Fig. 16, the yoke may be provided with a V-groove in which the guide shaft is fixed. According to the sixth embodiment, the following advantage can be obtained, in addition to the advantages obtainable with the first embodiment. That is, the coupling layer between the V-groove and the guide shaft can effectively damp the vibration of the guide shaft, and high precision control operation can be achieved. As has been described above in detail, the optical disk apparatus of the present invention has the following advantages: (1) The high-frequency vibration of the magnetic support rails (guide shafts) 4 is not transmitted to the movable optical body 5, and stable control operation can be carried out. (2) The support unit has a high elasticity in a direction in which a pre-load is applied, and a high rigidity in a direction in which the support unit moves. (3) Utilizing the elasticity of the plate spring 14 after assembly, it is possible to adjust the inclination angle of the pick-up body 6 so as to set the optical axis at an optimal angle. Thereafter, at least two of gaps are filled with a thermosetting, room temperature setting, or photo-setting adhesive or filler, and the desired state of the optical axis is maintained. (4) Vibration can effectively be damped, and high-precision control operation can be carried out. (5) When the pick-up body 6 collides with the stopper, the moment to rotate the pick-up body 6 is not generated, and the bearings are not damaged. (6) Since the distance between the spindle motor and the pick-up body 6 can be exactly determined, the pick-up body 6 does not collide with the spindle motor.

Claims: Optical disk read/write apparatus including support apparatus for supporting a lens (29) so the lens is linearly movable, the support apparatus comprising: a movable carrier (6) on which the lens (29) is mounted; guide means (4) for guiding the carrier (6), said guide means (4) extending in the direction in which the carrier moves, said guide means (4) including a pair of guide rails (4) extending in the direction in which the carrier (6) moves; support means mounted on said guide means (4), for supporting the carrier (6) movable along the guide means (4); and coupling means (14,51) for elastically coupling the support means (11,12) to the carrier (6), characterized in that said support means includes first and second pairs of rollers (11), which can be rolled on one of the guide rails (4), and third and fourth pairs of rollers (11), which can be rolled on the other guide rails (4), and in that said first and second pairs of rollers (11) are supported by a common block (13) which is elastically supported and said third and fourth pairs of rollers (11) are supported by a common block (13) which is elastically supported. Apparatus according to claim 1, characterized in that said coupling means (14,51) includes first elastic means (14) for elastically supporting both the first and second pairs of rollers (11), each of which pairs are supported on a common block (13) which is elastically supported. Apparatus according to claim 2, characterized in that said coupling means (14,51) includes second elastic means (14) for elastically supporting both the third and fourth pairs of rollers (11), each of which pairs are supported on a common block (13) which is elastically supported. Apparatus according to claim 3, characterized in that said carrier (16) has opposite first and second side surfaces, said first elastic means (14) is fixed to the first side surface, and the second elastic means (14) is fixed to the second side surface. Apparatus according to claim 4, characterized in that said first elastic means (14) includes a first plate spring (14) having one end and the other end, to which the first and second pairs of rollers (11) are respectively fixed, and first gaps between the first plate spring (14) and said first side surface, and said second elastic means (14) includes a second plate spring (14) having one end and the other end, to which the third and fourth pairs of rollers (11) are respectively fixed, and second gaps (23) between the second plate spring and said second side surface. Apparatus according to claim 5, characterized in that said first elastic means (14) includes first and second blocks (13) for fixing the first and second pairs of rollers (11) to the one and other ends of the first plate spring (14), and said second elastic means (14) includes third and fourth blocks (13) for fixing the third and fourth pairs of rollers (11) to the one and other ends of the second plate spring (14). Apparatus according to claim 5, characterized in that said first elastic means (14) includes pins (12) for rotatably fixing the first and second pairs of rollers (11) to the first and second blocks (13), and said second elastic means (14) includes pins (12) for rotatably fixing the third and fourth pairs of rollers (12) to the third and fourth blocks (13). Apparatus according to claim 5, characterized in that said first elastic means (14) includes a coagulating agent (24) filled in the first gaps (23), and said second elastic means (14) includes a visco-elastic agent (25) filled in the second gaps (23). Apparatus according to claim 4, characterized in that said first elastic means (14) includes a first plate spring (14) having one tongue portion (14A) and the other tongue portion (14B), to which the first and second pairs of rollers (11) are respectively fixed, and first gaps (23) between the first plate spring (14) and said first side surface, and said second elastic means (14) includes a second plate spring (14) having one tongue portion (14A) and the other tongue portion (14B), to which the third and fourth pairs of rollers (11) are respectively fixed, and second gaps (23) between the second plate spring (14) and said second side surface. Apparatus according to claim 9, characterized in that said first elastic means (14) includes first and second pairs of block segments (13A, 13B) for fixing the first and second pairs of rollers (11) to the one and other tongue portions (14A, 14B) of the first plate spring (14), and said second elastic means (14) includes third and fourth pairs of block segments (13A, 13B) for fixing the third and fourth pairs of rollers to the one and other tongue portions of the second plate spring. Apparatus according to claim 9, characterized in that said first elastic means (14) includes pins (12) for rotatably fixing the first and second pairs of rollers (11) to the first and second pairs of block segments (13), and said second elastic means (14) includes pins (12) for rotatably fixing the third and fourth pairs of rollers (11) to the third and fourth pairs of block segments (13A, 13B). Apparatus according to claim 9, characterized in that said first elastic means (14) includes a coagulating agent (24) filled in the first gaps (23), and the second elastic means (14) includes a visco-elastic agent (25) filled in the second gaps (23). Apparatus according to claim 4, characterized in that said first elastic means (14) includes a first pair of plate springs (14) having one end and the other end, one end being fixed to the carrier (6), first gaps (23) being formed between said first pair of plate springs (14) and said first side surface, and said second elastic means (14) includes a second pair of plate springs (14) having one end and the other end, one end being fixed to the carrier (6), second gaps (26) being formed between said second pair of plate springs (14) and said second side surface. Apparatus according to claim 13, characterized in that said first elastic means (14) includes first and second pairs of blocks (13) for fixing the first and second rollers (11) to the other ends of the first pair of plate springs (14), and said second elastic means (14) includes third and fourth pairs of blocks (13) for fixing the third and fourth rollers (11) to the other ends of the second pair of plate springs (14). Apparatus according to claim 14, characterized in that said first elastic means (14) includes pins (12) for rotatably fixing the first and second pairs of rollers (11) to the first and second pairs of blocks (13), and said second elastic means (14) includes pins (12) for rotatably fixing the third and fourth pairs of rollers (11) to the third and fourth pairs of blocks (13). Apparatus according to claim 13, characterized in that said first elastic means (14) includes a coagulating agent (24) filled in the first gaps (23), and said second elastic means (14) includes a visco-elastic agent (25) filled in the second gaps (23).

Inventors: KASAHARA AKIHIRO, KASAHARA, AKIHIRO, KASAHARA, AKIHIRO, C/O INTELLECTUAL PROPERTY DIV.
Applicants: TOSHIBA KK, KABUSHIKI KAISHA TOSHIBA
Application year: 1991
Main classification: G11B7
IPC codes: G11B7