JP2007294041A - Lens holder for optical pickup, molding die and molding method of the lens holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the dimensional precision of a lens mounting opening and a hub part of a lens holder. <P>SOLUTION: A molding die 13 for the lens holder is composed of an upper die 13A and a lower die 13B whose connecting surfaces 13a and 13b at the same level of the upper surface of a holder body are connected with each other. A void 14 for a lens mounting opening is formed at the upper die, and respective voids 15 to 17 for the holder body, a balancer part and a hub part are formed at the lower die 13B. At a position opposing the void 16 for the balancer part on the connecting surface 13b of the lower die 13B, a side gate 18 is formed. Between the void 16 for the balancer part and the void 17 for the hub part on the connecting surface 13a of the upper die 13A, a rectification protrusion 23 is integrally formed projecting while opposing the side gate 18. Thus, synthetic resin with which a gap between the upper die 13A and the lower die 13b is filled is made to flow into the void 17 for the hub part along the rectification protrusion 23 from the side gate 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a lens holder for an optical pickup used in a disk device (for example, a DVD player or a DVD recorder), a molding die thereof, and a molding method thereof, and more particularly, to improve the dimensional accuracy of a lens mounting opening and a boss portion of the lens holder. It is to improve.

Conventionally, as an example of a disk device, there are those shown in FIGS. This includes a holder main body 1A having a bearing hole 1a penetrating substantially at the center and a lens mounting opening 1b formed at one end, and a balancer portion 1B integrally projecting from the lower surface of the other end of the holder main body 1A. The holder main body 1A has a synthetic resin optical lens holder 1 provided integrally with the lower surface of the central portion of the holder body 1A and having a boss portion 1C formed by extending the bearing hole 1a therein. The focus coil 3 with the magnetic body 2 is externally fitted, the tracking coil 4 is attached to both side surfaces of the holder body 1A, and the objective lens OL is attached to the lens attachment opening 1b, whereby an optical pickup is formed. The boss 1 </ b> C is fitted on a shaft 7 on an act base 6 with a magnet 5. 8 is a slide base movable along the radial direction of the disk, 9 is an inclination adjusting bolt for connecting the act base 6 to the slide base 8, 10 is a collimator lens, 11 is a flexible flat cable, and a focus coil 3 and tracking coil 4
It is connected to the.

The information reading procedure will be described. By focusing and energizing the focus coil 3, the lens holder 1 is focused a and b along the shaft 7, and by energizing and energizing the tracking coil 4, the lens holder 1. Tracking around shaft 7 c
, D, the laser beam is projected onto the disk D through the objective lens OL, and the information recorded on the disk D is read based on the reflected light.

As shown in FIG. 11A, the molding die 13 of the lens holder 1 is an upper die 13A in which joining surfaces 13a and 13b at the same level as the upper surface 1c (see FIG. 10) of the holder body 1A are joined together.
And the lower mold 13B, the upper mold 13A is formed with a gap 14 for the lens mounting opening 1b, and the lower mold 13B has a gap 15-15 for the holder body 1A, the balancer section 1B, and the boss section 1C.
Is formed.

An example of the forming method will be described. As shown by phantom lines in FIG. 11A, a side gate 18 is formed at a position facing the balancer 1B gap 16 on the joint surface 13b of the lower mold 13B. 18 is filled with a synthetic resin such as a liquid crystal polymer between the upper and lower molds 13A and 13B by an injection molding machine 19 (see FIG. 11B), and the lens holder 1 is taken out between the upper and lower molds 13A and 13B [FIG. c)].

According to the above configuration, the synthetic resin is horizontally filled from the side gate 18 toward the gap 15 for the holder main body 1A.
The gap 14 for b can be sufficiently filled with the synthetic resin, but the gap 15 for the holder body 1A.
It is difficult to smoothly flow the synthetic resin into the gap 17 for the boss portion 1C. For this reason,
The dimensional accuracy (roundness, cylindricity, surface roughness, etc.) of the boss 1C after molding tends to be low, and there is a possibility of adversely affecting the operations of the focusing a, b and tracking c, d of the lens holder 1.

Another example of the molding method will be described. This is described in Patent Document 1, and as shown by a solid line in FIG. 11A, faces the gap 17 for the boss portion 1C of the upper die 13A. A pin gate 20 is formed in the portion, and the upper and lower molds 13A, 1 are formed from the pin gate 20 by an injection molding machine 19.
3B is filled with a synthetic resin such as a liquid crystal polymer (see FIG. 11B), and both upper and lower molds 13A,
The lens holder 1 is taken out between 13B [see FIG. 11 (c)].
JP-A-6-27360

In the above configuration, the synthetic resin is vertically filled from the pin gate 20 toward the boss part 1C gap 17, and due to the straightness of the synthetic resin, the synthetic resin is sufficiently filled in the boss part 1C gap 17. Filling can improve the dimensional accuracy (roundness, cylindricity, surface roughness, etc.) of the boss 1C after molding, but the synthetic resin should sufficiently flow into the gap 14 for the lens mounting opening 1b. Therefore, the dimensional accuracy (roundness, cylindricity, surface roughness, etc.) of the lens mounting opening 1b after molding becomes low, and the lens mounting opening 1b may be twisted or deformed, for example.

An object of the present invention is to provide a lens holder for an optical pickup, a molding die thereof, and a molding method thereof in which the dimensional accuracy of a lens mounting opening and a boss portion is improved in view of the above-described conventional drawbacks.

In order to achieve the above object, a first aspect of the present invention provides a holder body made of synthetic resin having a bearing hole penetrating substantially at the center and a lens mounting opening formed at one end thereof, and the other end portion of the holder body. A balancer portion integrally projecting on the lower surface, and a boss portion projecting integrally from the lower surface of the central portion of the holder body and extending the bearing hole therein. For an optical pickup that is fitted with a tracking coil on both sides of the holder body, an objective lens is mounted on the lens mounting opening, and the boss is fitted on a shaft on an act base with magnet. A concave portion having a lateral width substantially the same as the outer diameter of the boss portion and a depth set to substantially half the thickness of the holder body, between the boss portion and the balancer portion on the upper surface of the holder body. Formed It is characterized in that there.

According to the second aspect of the present invention, a synthetic resin holder main body having a bearing hole penetrating substantially at the center and a lens mounting hole formed at one end thereof and integrally projectingly provided on the lower surface of the other end of the holder main body. A balancer portion, and a boss portion formed integrally with the lower surface of the central portion of the holder body and extending the bearing hole therein, and a focus coil is fitted on the boss portion, and the holder body Tracking coils are attached to both side surfaces of the lens, and an objective lens is attached to the lens mounting hole.
A molding die for an optical pickup lens holder in which the boss portion is externally fitted to a shaft on an act base with a magnet, and an upper die in which joint surfaces at the same level as the upper surface of the holder body are joined together. And a lower mold, a gap for a lens mounting opening is formed in the upper mold,
The lower mold is formed with a gap for the holder main body, the balancer part, and the boss part, and a side gate is formed at a position facing the balancer part gap on the joint surface of the lower mold, and the upper mold is opposed to the side gate. A straightening protrusion is integrally provided between the balancer gap and the boss gap on the joint surface of the joint surface, and synthetic resin filled between the upper die and the lower die from the side gate is used as the straightening protrusion. It is characterized in that it is made to flow along the gap for the boss part along.

The invention according to claim 3 is the invention according to claim 2, wherein the rectifying protrusion is formed along a direction orthogonal to the longitudinal direction of the side gage, and the lateral width of the rectifying protrusion is for the boss part. It is characterized in that it is substantially the same as the outer diameter of the gap and its height is set to substantially half of the thickness of the holder body gap.

A fourth aspect of the invention is characterized in that, in the invention of the second or third aspect, the side gate facing surface of the rectifying protrusion is inclined obliquely downward toward the boss portion gap.

According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the side gate facing surface of the rectifying protrusion is formed in a substantially circular arc shape in plan view with the boss portion gap as a center. It is characterized by that.

According to the sixth aspect of the present invention, a synthetic resin holder main body having a bearing hole penetrating substantially at the center and a lens mounting hole formed at one end thereof is integrally projected on the lower surface of the other end of the holder main body. A balancer portion, and a boss portion formed integrally with the lower surface of the central portion of the holder body and extending the bearing hole therein, and a focus coil is fitted on the boss portion, and the holder body Tracking coils are attached to both side surfaces of the lens, and an objective lens is attached to the lens mounting hole.
In the optical pickup lens holder in which the boss portion is externally fitted to the shaft on the magnet-equipped act base, the optical pickup lens holder includes an upper die and a lower die obtained by joining the joint surfaces at the same level as the upper surface of the holder body. The upper mold has a lens mounting opening gap formed therein, and the lower mold has a holder main body, a balancer section, and a boss section, and a balancer section on the joint surface of the lower mold. A side gate is formed at a position facing the air gap, and the lateral width is set between the balancer gap air gap and the boss air gap on the upper mold joint surface facing the side gate. The rectifying protrusions are almost the same as the height of the holder body gap, and the rectifying protrusions are integrally projected, and the side gate facing surface of the rectifying protrusions is inclined obliquely downward toward the boss gap. And the rhinoceros The gate facing surface is formed in a substantially arc shape in plan view around the gap for the boss portion, and the synthetic resin is filled between the upper and lower molds from the side gate, and the filled synthetic resin is filled with the side gate facing surface of the rectifying protrusion. And the lens holder is taken out from both the upper and lower molds.

The invention according to claim 1 relates to a lens holder for an optical pickup (see FIGS. 1 to 3), and according to this, the lens holder is reduced in weight by the amount of the recess formed on the upper surface of the holder body, The synthetic resin filled in the holder main body gap at the time of molding due to the presence of the concave portion is divided into the horizontal direction and the vertical direction, and the synthetic resin divided in the horizontal direction is sufficiently filled into the lens mounting port gap, The synthetic resin split in the vertical direction is sufficiently filled in the gap for the boss part, improving the dimensional accuracy (roundness, cylindricity, surface roughness, etc.) of the lens mounting port and boss part after molding. The focusing and tracking operations of the lens holder can be performed precisely.

The invention according to claim 2 is a molding die for a lens holder for an optical pickup (see FIGS. 4 to 6).
According to this, since the side gate is adopted, the lens mounting opening is sufficiently dimensioned by filling the gap for the lens mounting opening sufficiently with the straightness of the synthetic resin. By improving accuracy (roundness, cylindricity, surface roughness, etc.) and preventing the lens mounting opening from being twisted or deformed, for example, by adopting a rectifying protrusion As in the case of the pin gate, the synthetic resin can smoothly flow into the gap for the boss portion, and the dimensional accuracy (roundness, cylindricity, surface roughness, etc.) of the boss portion after molding can be improved.

In short, the present invention provides a molding die having the advantages of a side gate type and a pin gate type.

According to the third aspect of the present invention, the rectifying protrusion is formed along a direction orthogonal to the longitudinal direction of the side gate, and the lateral width of the rectifying protrusion is substantially the same as the outer diameter of the boss portion gap. Since the height is set to approximately half of the thickness of the holder main body gap, the synthetic resin can be made to flow substantially evenly into the entire boss portion gap along the straightening protrusion.

According to the fourth aspect of the present invention, the synthetic resin can smoothly flow into the boss portion gap along the side gate facing surface inclined obliquely downward of the rectifying protrusion.

The invention according to claim 5 relates to a modified example (see FIG. 7). According to this, the synthetic resin is attached to the lens along the side gate facing surface formed in a substantially circular arc shape in plan view of the rectifying protrusion. It can be made to flow more smoothly toward the mouth side gap.

The invention described in claim 6 relates to a method for forming a lens holder for an optical pickup, and according to this, the dimensional accuracy (roundness, cylindricity, surface roughness, etc.) of the lens mounting opening and the boss portion is provided.
It is possible to precisely mold a lens holder with improved s.

1 to 3 show a disk device having an optical pickup lens holder 1 according to an embodiment of the present invention. A boss portion 1C and a balancer portion 1 on an upper surface 1c of a holder main body 1A.
Between B, a recess 22 is formed in which the lateral width t1 is substantially the same as the outer diameter t2 of the boss portion 1C and the depth h1 is set to substantially half the thickness h2 of the holder body 1A. Configurations other than the above are shown in FIGS.
Since the configuration is almost the same as that shown in 0, the same reference numerals are given to the same portions and the description thereof is omitted.

The molding die 13 of the lens holder 1 will be described. As shown in FIGS.
A side gate 18 is formed at a position facing the balancer part 1B gap 16 on the 3B joint surface 13b, and the balancer part 1B gap 16 and boss part 1C on the joint surface 13a of the upper mold 13A are opposed to the side gate 18. A rectifying protrusion 23 is provided integrally with the air gap 17. Since the configuration of the molding die 13 other than the above is substantially the same as the configuration shown in FIG. 11, the same parts are denoted by the same reference numerals and the description thereof is omitted.

The rectifying protrusion 23 is for forming the concave portion 22 and includes a side gate 1.
8 is formed in a direction orthogonal to the longitudinal direction, and its lateral width t1 is substantially the same as the outer diameter t2 of the boss 1C gap 17 and its height h1 is the thickness h2 of the holder body 1A gap 15. The side gate facing surface 23a of the rectifying protrusion 23 is set to substantially half, and the boss 1C gap 1
7 is inclined obliquely downward.

As an example of specific dimensions, the lateral width t1 of the recess 22 (rectifying protrusion 23) is 5 mm, and the recess 2
2 The depth h1 (the height h1 of the rectifying protrusion 23) is 0.5 mm, the lateral width t3 of the side gate 18 is 0.4 mm, and the height h3 of the side gate 18 is 0.2 mm.

4A and 4B, a synthetic resin such as a liquid crystal polymer is filled between the upper and lower molds 13A and 13B from the side gate 18 by an injection molding machine 19.
5 (a)], the filled synthetic resin is used as the side gate facing surface 23a of the rectifying projection 23.
Then, the lens holder 1 is taken out from between the upper and lower molds 13A and 13B [see FIG. 5B].

According to the above configuration, the lens holder 1 is reduced in weight by the concave portion 22 formed on the upper surface 1c of the holder main body 1A, and the holder main body 1 is formed at the time of molding due to the presence of the concave portion 22 (rectifying projection portion 23).
The synthetic resin filled in the A gap 15 is divided into a horizontal direction and a vertical direction. The synthetic resin divided in the horizontal direction is sufficiently filled into the gap 14 for the lens mounting opening 1b and is divided in the vertical direction. Since the formed synthetic resin is sufficiently filled in the gap 17 for the boss 1C, the dimensional accuracy (roundness, cylindricity, surface roughness, etc.) of the lens mounting opening 1b and the boss 1C after molding is improved, The operations of focusing a and b and tracking c and d of the lens holder 1 can be performed precisely.

What is important here is that since the side gate 18 is employed, the lens mounting opening 1 after molding is sufficiently filled with the synthetic resin in the gap 14 for the lens mounting opening 1b due to the straightness of the synthetic resin.
It is possible to improve the dimensional accuracy (roundness, cylindricity, surface roughness, etc.) of b and prevent the lens mounting opening 1b from being twisted or deformed, for example, and in addition to this, the rectifying protrusion 23
As in the case of the pin gate 20 (see FIG. 11), the synthetic resin flows smoothly into the gap 17 for the boss 1C, and the dimensional accuracy (roundness, cylindricity) of the boss 1C after molding is obtained. ,
Surface roughness, etc.) can be improved.

In short, the molding die 13 having the advantages of the side gate 18 type and the pin gate 20 type is provided.

Further, the rectifying protrusion 23 is formed along a direction orthogonal to the longitudinal direction of the side gate 18, and the lateral width t1 of the rectifying protrusion 23 is substantially the same as the outer diameter t2 of the gap 17 for the boss portion 1C and its height is high. Since the length h1 is set to substantially half of the thickness h2 of the holder main body 1A gap 15, the synthetic resin is made to pass along the side gate facing surface 23a of the rectifying projection 23 and the gap 17 for the boss 1C.
It can be made to flow almost evenly with respect to the whole.

FIG. 7 shows a modification of the rectifying protrusion 23. The side gate facing surface 23a of the rectifying protrusion 23 is formed in a substantially arc shape in plan view around the gap 17 for the boss 1C. Since the configuration other than that is substantially the same as the configuration shown in FIGS.

According to the said structure, the side gate opposing surface 2 formed in the planar view substantially circular arc shape of the baffle projection part 23
The synthetic resin can flow more smoothly along the lens mounting opening 1b side gap 14 along 3a.

It is a longitudinal cross-sectional view of the principal part of the disc apparatus which has the lens holder for optical pick-ups which is one Embodiment of this invention. It is the same top view. (A) is a perspective view of the lens holder, and (b) is a longitudinal sectional view thereof. (A) is a longitudinal cross-sectional view of the molding die for the lens holder, and (b) is an AA arrow view. (A) is a longitudinal cross-sectional view which shows the shaping | molding method of the lens holder, (b) is a longitudinal cross-sectional view of the lens holder. It is a perspective view of the upper mold | type of the molding die. The horizontal sectional view which shows the modification of the same rectification protrusion part, (b) is a perspective view of the upper mold | type of the molding die. It is a longitudinal cross-sectional view which shows a prior art example. It is the same top view. (A) is a perspective view of the lens holder, and (b) is a longitudinal sectional view thereof. (A) is a longitudinal sectional view of the molding die for the lens holder, (b) is a longitudinal sectional view showing a molding method of the lens holder, and (b) is a longitudinal sectional view of the lens holder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens holder 1A Holder main body 1B Balancer part 1C Boss part 1a Bearing hole 1b Lens mounting port 1c Upper surface of holder main body 3 Focus coil 4 Tracking coil 5 Magnet 6 Act base 7 Shaft 13 Molding die 13A Upper die 13a Upper die joining surface 13B Lower mold 13b Lower mold joint surface 14 Lens mounting opening gap 15 Holder body gap 16 Balancer section gap 17 Boss section gap 18 Side gate 22 Recess 23 Rectification projection section 23a Side gate facing surface of the rectification projection section OL Objective Lens t1 Width of concave portion (rectifying protrusion) t2 Outer diameter of boss portion (air gap for boss portion) h1 Height of concave portion (height of straightening protrusion)
h2 Thickness of holder body (space for holder body)

Claims (6)

A synthetic resin holder main body having a bearing hole penetrating substantially at the center and a lens mounting opening formed at one end, a balancer portion integrally projecting from the lower surface of the other end of the holder main body, and the center of the holder main body And a boss part formed by extending the bearing hole in the interior thereof, and a focus coil is fitted on the boss part, and tracking coils are attached to both side faces of the holder body. An optical pickup lens holder in which an objective lens is mounted in the lens mounting port, and the boss portion is externally fitted to a shaft on an act base with a magnet,
Between the boss portion and the balancer portion on the upper surface of the holder body, a recess having a lateral width substantially the same as the outer diameter of the boss portion and a depth set to substantially half the thickness of the holder body is formed. An optical pickup lens holder. A synthetic resin holder main body having a bearing hole penetrating substantially at the center and a lens mounting hole formed at one end, a balancer portion integrally projecting from the lower surface of the other end of the holder main body, and the center of the holder main body And a boss part formed by extending the bearing hole in the interior thereof, and a focus coil is fitted on the boss part, and tracking coils are attached to both side faces of the holder body. An optical pickup lens holder molding die in which an objective lens is mounted in the lens mounting hole, and the boss portion is externally fitted to a shaft on an act base with a magnet, and an upper surface of the holder body It consists of an upper mold and a lower mold in which bonding surfaces of the same level are bonded to each other. A gap for a lens mounting opening is formed in the upper mold, and each of the voids for the holder body, the balancer section, and the boss section is formed in the lower mold. form A side gate is formed at a position facing the balancer gap on the lower mold joint surface, and between the balancer gap and the boss gap on the upper mold joint surface facing the side gate. A rectifying protrusion is integrally formed, and the synthetic resin filled between the upper die and the lower die is allowed to flow into the boss gap along the rectifying protrusion from the side gate. Mold for lens holder for optical pickup. The rectifying protrusion is formed along a direction orthogonal to the longitudinal direction of the side gate, the width of the rectifying protrusion is substantially the same as the outer diameter of the boss gap, and the height thereof is the thickness of the holder gap. The molding die for the lens holder for an optical pickup according to claim 2, wherein the molding die is set to approximately half of the length. 4. The molding die for a lens holder for an optical pickup according to claim 2, wherein the side gate facing surface of the rectifying protrusion is inclined obliquely downward toward the boss gap. The molding of the lens holder for an optical pickup according to any one of claims 2 to 4, wherein the side gate facing surface of the rectifying protrusion is formed in a substantially arc shape in plan view with the boss portion gap as a center. Mold. A synthetic resin holder main body having a bearing hole penetrating substantially at the center and a lens mounting hole formed at one end, a balancer portion integrally projecting from the lower surface of the other end of the holder main body, and the center of the holder main body And a boss part formed by extending the bearing hole in the interior thereof, and a focus coil is fitted on the boss part, and tracking coils are attached to both side faces of the holder body. In the lens holder for an optical pickup in which an objective lens is mounted in the lens mounting hole, and the boss portion is externally fitted to a shaft on an act base with a magnet.
The upper die has a molding die composed of an upper die and a lower die in which joint surfaces at the same level as the upper surface of the holder main body are joined to each other. Body,
Each gap for the balancer part and the boss part is formed, a side gate is formed at a position facing the balancer part gap on the lower mold joint surface, and the balancer part of the upper mold joint surface facing the side gate Between the gap for use and the gap for the boss part, a rectifying protrusion having a lateral width substantially the same as the outer diameter of the gap for the boss part and a height set to substantially half the thickness of the gap for the holder body is integrally projected. The side gate facing surface of the rectifying protrusion is inclined obliquely downward toward the boss portion gap, and the side gate facing surface is formed in a substantially arc shape in plan view around the boss portion gap. Synthetic resin is filled between the upper and lower molds from the side gate, and the filled synthetic resin flows into the gap for the boss part and the gap for the lens mounting opening along the side gate facing surface of the rectifying protrusion, and from between the upper and lower molds. Special feature to take out the lens holder Molding method of the optical pickup lens holder to.

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