JP4329803B2 - Optical pickup tilt adjustment mechanism - Google Patents

Description

  The present invention relates to a tilt adjustment mechanism of an optical pickup. For example, in an optical disk apparatus corresponding to an optical disk such as a DVD (Digital Versatile Disk) or a BD (high density optical disk using a blue laser beam), the inclination of the optical pickup is adjusted. The present invention relates to a tilt adjustment mechanism.

  The movement of the optical pickup in the disk radial direction in the optical disk apparatus is guided by a guide shaft. For this reason, if the guide shaft is tilted, the optical pickup is also tilted and its optical performance is degraded. In order to solve this problem, a technique for adjusting the tilt of the optical pickup by adjusting the tilt of the guide shaft has been conventionally proposed (see, for example, Patent Documents 1 to 3). However, all of the conventionally proposed tilt adjustment mechanisms have a complicated structure and have problems such as difficulty in assembly when mounted on an optical disc apparatus. Such a problem will be described below with a conventional example.

FIG. 5 shows an example of a conventionally known tilt adjustment mechanism. An optical pickup (not shown) is attached to the guide shaft 2, and a spring 14 is attached to the end of the guide shaft 2. An adjustment screw 15 is attached to the drive chassis 3, and the tip of the adjustment screw 15 is positioned so as to contact the end of the guide shaft 2 from below. Since the spring 14 is biased so as to push down the guide shaft 2 toward the drive chassis 3, when the adjustment screw 15 is rotated, the end of the guide shaft 2 comes into contact with the tip of the adjustment screw 15. It is pushed up or down while maintaining the state. Since the tilt of the guide shaft 2 can be changed by pushing up or pushing down the end of the guide shaft 2, the tilt of the optical pickup can be adjusted.
JP 2001-229548 A JP 2001-52345 A Utility Model Registration No. 3082214

  However, in the tilt adjustment mechanism shown in FIG. 5, in the axial direction of the guide shaft 2, the spring 14 acts on the guide shaft 2 from above, and the adjustment screw 15 acts on the guide shaft 2 from below. There is a position shift. For this reason, there is a problem that the guide shaft 2 bends during assembly and tilt adjustment. When the guide shaft 2 is deflected, the sliding performance of the optical pickup is deteriorated, and problems such as the degree of inclination of the optical pickup differ depending on the position on the guide shaft 2 occur.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a tilt adjustment mechanism that has a simple structure but does not generate deflection in a guide shaft that guides the movement of the optical pickup, and the tilt adjustment mechanism. An optical disc apparatus is provided.

In order to achieve the above object, the optical disk apparatus of the first invention supports two guide shafts on the drive chassis for guiding movement in the disk radial direction on both sides of the optical pickup, and adjusts the inclination of the guide shaft. by an optical disk apparatus having a tilt adjusting mechanism for adjusting the inclination of the optical pickup with respect to the optical disc, the tilt adjustment mechanism, a holder attached to both ends of the guide shaft, all of its holder on the drive chassis An adjustment screw fixed by a screw structure; and a spring for eliminating play of the screw structure between the drive chassis and an end surface of the holder on the drive chassis side, and the screw structure includes the drive A first screw portion that is coupled to the chassis and a second screw portion that is coupled to the holder. Is the first greater than the pitch of the threaded portion is the second threaded portion, said it twisting direction is reversed between the first threaded portion and said second threaded portion, the nominal diameter of the second screw portion the first rather smaller than the nominal diameter of the threaded portion, and the hole of the adjustment screws that penetrate to the holder upper surface on the holder, above the fixing position of the adjusting screw which is parallel the drive chassis and substantially An optical disc apparatus comprising a hole for the guide shaft provided on the optical disc.

  The tilt adjustment mechanism of the second invention is a tilt adjustment mechanism that supports a guide shaft for guiding the movement of the optical pickup on the drive chassis, and adjusts the inclination of the optical pickup with respect to the optical disc by adjusting the inclination of the guide shaft. It has a holder attached to an end of the guide shaft, and an adjusting screw for fixing the holder to the drive chassis with a screw structure.

  A tilt adjustment mechanism according to a third aspect of the invention is characterized in that, in the second aspect of the invention, a spring for eliminating play of the screw structure is provided between the drive chassis and the holder.

  According to a fourth aspect of the present invention, there is provided the tilt adjusting mechanism according to the second or third aspect, wherein the screw structure includes a first screw portion coupled to the drive chassis and a second screw portion coupled to the holder. It is characterized by being.

  The tilt adjustment mechanism according to a fifth aspect of the present invention is characterized in that, in the fourth aspect, the first screw portion and the second screw portion have different pitches.

  According to a sixth aspect of the present invention, there is provided the tilt adjusting mechanism according to the fourth or fifth aspect, wherein the first screw portion and the second screw portion have opposite twist directions.

  In a tilt adjustment mechanism according to a seventh aspect of the present invention, in any one of the fourth to sixth aspects, the nominal diameter of the second screw portion is smaller than the nominal diameter of the first screw portion.

  An optical disc apparatus according to an eighth aspect of the invention includes the tilt adjustment mechanism according to any one of the second to seventh aspects of the invention.

  Since the tilt adjusting mechanism according to the present invention is configured such that the holder attached to the end of the guide shaft is fixed to the drive chassis with a screw structure, there is a force acting in the direction of pressing the guide shaft from above. do not do. Therefore, although the tilt adjustment mechanism has a simple structure, the guide shaft that guides the movement of the optical pickup does not bend. As a result, high optical performance can be obtained by improving the sliding performance of the optical pickup. In addition, if a spring is provided between the drive chassis and the holder for eliminating the screw-structure play, smooth and stable tilt adjustment can be performed.

  If the screw structure of the adjustment screw is composed of a first screw portion that is coupled to the drive chassis and a second screw portion that is coupled to the holder, the accuracy of tilt adjustment can be changed. For example, if the first screw portion and the second screw portion have different pitches or reverse the twist direction, fine adjustment and coarse adjustment can be performed by changing the screw feed amount. Further, if the nominal diameter of the second screw portion is made smaller than the nominal diameter of the first screw portion, it becomes possible to easily attach the adjusting screw to the drive chassis.

  Embodiments of an optical pickup tilt adjusting mechanism and an optical disc apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 shows the appearance of the tilt adjustment mechanism 7, and FIG. 2 shows the internal structure of the tilt adjustment mechanism 7. FIG. 3A shows an adjustment screw 5 constituting the tilt adjustment mechanism 7, and FIG. 3B shows an adjustment screw 6 as another specific example applied to the tilt adjustment mechanism 7. FIG. 4 schematically shows a schematic configuration of the optical disc apparatus 9 having the tilt adjusting mechanism 7.

  As shown in FIG. 4, the optical disk device 9 includes a drive chassis 3 to which each element is attached, an optical pickup 8 having an objective lens 8a, and two guides for guiding movement in the disk radial direction on both sides of the optical pickup 8. A guide shaft 2 and a tilt adjustment mechanism 7 that supports the guide shaft 2 on the drive chassis 3 and adjusts the inclination of the optical pickup 8 with respect to the optical disk DK by adjusting the inclination of the guide shaft 2 are configured. As shown in FIGS. 1 and 2, the tilt adjustment mechanism 7 includes a holder 1 attached to the end of the guide shaft 2 and an adjustment screw 5 that fixes the holder 1 to the drive chassis 3 with a screw structure. In addition, a spring 4 is provided between the drive chassis 3 and the holder 1 to eliminate screw structure play.

  As shown in FIGS. 2 and 3A, the screw structure of the adjusting screw 5 is composed of a first screw portion 5a coupled to the drive chassis 3 and a second screw portion 5b coupled to the holder 1. ing. The pitch of the 2nd screw part 5b is smaller than the pitch of the 1st screw part 5a, and the nominal diameter of the 2nd screw part 5b is smaller than the nominal diameter of the 1st screw part 5a. For this reason, the drive chassis 3 is provided with a screw hole 3a for coupling to the first screw portion 5a so as to correspond to the screw portions 5a and 5b, and the holder 1 is coupled to the second screw portion 5b. A screw hole 1b is provided.

  A method for assembling the tilt adjustment mechanism 7 will be described. First, the adjusting screw 5 is attached to the drive chassis 3. At this time, the adjusting screw 5 is attached to the screw hole 3 a from the back side of the drive chassis 3. As described above, since the nominal diameter of the second screw portion 5b is smaller than the nominal diameter of the first screw portion 5a, the first screw portion 5a can be easily coupled to the screw hole 3a of the drive chassis 3. . Next, the end of the guide shaft 2 is press-fitted into the hole 1 a of the holder 1. Since the screw hole 1b penetrates to the upper surface of the holder 1, if necessary, an adhesive may be dropped from above the screw hole 1b to fix the holder 1 and the guide shaft 2 with high strength with an adhesive. it can. Next, the adjusting screw 5 is attached to the holder 1. At this time, the second screw portion 5 b is coupled to the screw hole 1 b of the holder 1 so as to sandwich the spring 4 between the drive chassis 3 and the holder 1. As described above, since the urging force of the spring 4 acts so as to eliminate the backlash of the screw structure, smooth and stable tilt adjustment can be performed.

  As described above, the tilt adjusting mechanism 7 has a configuration in which the holder 1 attached to the end of the guide shaft 2 is fixed to the drive chassis 3 with a screw structure, so that the tilt adjusting mechanism 7 is pressed against the guide shaft 2 from above. There is no acting force. That is, in the structure in which both the guide shaft 2 and the adjusting screw 5 are attached to the holder 1, no biasing force that causes the guide shaft 2 to bend is applied. Therefore, the guide shaft 2 that guides the movement of the optical pickup 8 does not bend while the structure is easy and simple to manufacture. As a result, high optical performance can be obtained by improving the sliding performance of the optical pickup 8. In a general optical disc apparatus, the guide shaft 2 tilts at the time of tilt adjustment because the fulcrum interval of the guide shaft 2 is about 10 cm and the vertical movement (of the guide shaft 2) necessary for tilt adjustment is about 0.4 mm. For this reason, the clearance for the nominal diameter of the screw structure is acceptable.

  Next, a tilt adjustment method will be described. In the optical disk device 9 shown in FIG. 4, an optical pickup 8 for recording / reproducing information emits a laser beam from an objective lens 8a. As the laser beam is incident at an angle closer to perpendicular to the recording surface of the optical disc DK, information can be recorded / reproduced with higher accuracy. Since the two guide shafts 2 are configured to support the optical pickup 8 on both sides thereof and guide the movement in the disk radial direction, the optical pickup 8 with respect to the optical disk DK is adjusted by adjusting the inclination of the guide shaft 2. Can be adjusted. The tilt adjustment mechanism 7 adjusts the tilt of the optical pickup 8. By adjusting the tilt of the optical pickup 8, the laser beam emitted from the objective lens 8 a can be irradiated perpendicularly to the optical disk DK. In the optical disk device 9 shown in FIG. 4, the tilt adjustment mechanism 7 is provided at both ends of each guide shaft 2, and the tilt adjustment of the optical pickup 8 is performed by a total of four tilt adjustment mechanisms 7. In some cases, one of them may be omitted, and the tilt adjustment may be performed by a total of three tilt adjustment mechanisms 7.

  Since the tilt adjusting mechanism 7 supports each guide shaft 2 with the holder 1 attached to the end thereof, the tilt state of the guide shaft 2 changes when the holder 1 is moved upward or downward. . Therefore, the tilt of the optical pickup 8 can be adjusted by moving the holder 1 up and down. The upward movement or the downward movement of the holder 1 is performed by the rotation of the adjusting screw 5. However, if the pitch is different between the first screw portion 5a and the second screw portion 5b, the relationship between the feed amount of the adjusting screw 5 and the vertical movement of the holder 1 is also different. That is, a feed amount different from the feed amount of the adjusting screw 5 can be given to the holder 1.

  For example, assuming that the right-hand adjusting screw 5 moves upward with respect to the drive chassis 3, if the pitch of the first screw portion 5a and the pitch of the second screw portion 5b are the same, the drive chassis 3, the position of the holder 1 is fixed, and if the pitch of the first screw portion 5 a and the pitch of the second screw portion 5 b are different, the difference in pitch between the first screw portion 5 a and the second screw portion 5 b The holder 1 moves relative to the drive chassis 3 by the amount. Therefore, as the pitch of the second screw portion 5b is smaller than the pitch of the first screw portion 5a, the holder 1 moves more upward with respect to the drive chassis 3, and the first screw portion 5a is larger than the pitch of the first screw portion 5a. The greater the pitch of the two screw portions 5b, the greater the holder 1 moves downward relative to the drive chassis 3. Thus, if the pitch of the adjusting screw 5 is changed at each coupling portion, the tilt adjustable range can be easily adjusted.

  As shown in FIGS. 2 and 3A, the screw structure of the adjusting screw 5 is such that the pitch of the second screw portion 5b is smaller than the pitch of the first screw portion 5a. For this reason, when the right adjustment screw 5 moves upward relative to the drive chassis 3, the holder 1 moves upward relative to the drive chassis 3. If the difference in pitch between the first screw part 5a and the second screw part 5b is set to be small, the effect of finely adjusting the inclination of the guide shaft 2 can be obtained, and if the difference in pitch is set to be large, adjustment is possible. The inclination of the guide shaft 2 can be greatly changed by a small rotation of the screw 5.

  In the adjusting screw 6 shown in FIG. 3B, the twist direction is reversed between the first screw portion 6a and the second screw portion 6b. Thus, if a screw structure in which the twist direction of the screw portion 6a and the twist direction of the screw portion 6b are different is used for the tilt adjusting mechanism 7, a feed amount larger than the feed amount of the adjusting screw 6 is given to the holder 1. Can do. That is, since the holder 1 can obtain a large feed amount even when the adjustment screw 6 is rotated little, the inclination of the guide shaft 2 can be greatly changed.

  For example, assuming that the first screw portion 6a of the adjustment screw 6 is a right screw, when the adjustment screw 6 moves upward with respect to the drive chassis 3, the distance between the drive chassis 3 and the holder 1 increases. When the adjustment screw 5 moves downward with respect to the drive chassis 3, the distance between the drive chassis 3 and the holder 1 decreases. If the pitch of the 1st screw part 6a and the pitch of the 2nd screw part 6b are the same, the movement amount of the holder 1 will become larger than the movement amount of the screw 6 for adjustment in any case. However, if the difference in pitch between the first screw portion 6a and the second screw portion 6b is set to a predetermined size, the inclination of the guide shaft 2 can be finely adjusted, or the guide shaft 2 can be rotated with less rotation of the adjusting screw 6. The inclination can be changed greatly.

  If the screw structure of the adjusting screws 5 and 6 is composed of the first screw portions 5a and 6a coupled to the drive chassis 3 and the second screw portions 5b and 6b coupled to the holder 1, as described above, the tilt The accuracy of adjustment can be changed. For example, the first screw portion 5a and the second screw portion 5b have different pitches as shown in FIG. 3 (A), or the first screw portion 6a and the second screw portion 6b as shown in FIG. 3 (B). If the direction of twisting is reversed, fine adjustment and coarse adjustment can be made by changing the screw feed amount. Further, if the nominal diameters of the second screw parts 5b and 6b are made smaller than the nominal diameters of the first screw parts 5a and 6a, the adjustment screws 5 and 6 can be easily attached to the drive chassis 3. .

The perspective view which shows one Embodiment of a tilt adjustment mechanism. Sectional drawing which shows the tilt adjustment mechanism of FIG. The perspective view which shows the specific example of the screw for adjustment which comprises the tilt adjustment mechanism of FIG. FIG. 2 is a plan view showing a schematic configuration example of an optical disc apparatus having the tilt adjustment mechanism of FIG. 1. The perspective view which shows the prior art example of a tilt adjustment mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Holder 2 Guide shaft 3 Drive chassis 4 Spring 5, 6 Adjustment screw 7 Tilt adjustment mechanism 8 Optical pickup 9 Optical disk device

Claims (1)

An optical disc apparatus having a tilt adjustment mechanism that supports two guide shafts that guide movement in the radial direction of the disc on both sides of the optical pickup on the drive chassis and adjusts the inclination of the optical pickup relative to the optical disc by adjusting the inclination of the guide shaft. Because
The tilt adjusting mechanism includes a holder which is attached to both ends of the guide shaft,
Adjustment screws for fixing all the holders to the drive chassis with a screw structure;
A spring for eliminating play of the screw structure between the drive chassis and the end surface on the drive chassis side of the holder;
Have
The screw structure includes a first screw portion that is coupled to the drive chassis and a second screw portion that is coupled to the holder, and a pitch of the first screw portion is larger than a pitch of the second screw portion. the first twisting direction in the threaded portion and the second threaded portion is a reverse, nominal diameter of the second screw portion rather smaller than the nominal diameter of the first threaded portion,
The holder includes a hole for the adjustment screw penetrating to the upper surface of the holder, and a hole for the guide shaft that is substantially parallel to the drive chassis and provided above the fixing position of the adjustment screw. An optical disc device characterized by the above.

Images