JP2007149245A - Optical pickup - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely fix a collimator lens with a small amount of an adhesive. <P>SOLUTION: A lens reception seat 4 composed of a plurality of circular arc pieces 4A annularly arranged at gaps 14 of predetermined spaces is integrally formed with the end surface 1a of an optibase 1 to be larger in diameter than an optical passage hole 3 and in a concentric state, a collimator lens QWP is arranged in the lens reception seat 4, and a bank 17 is integrally formed with the optibase 1 to partition the gaps 14 in a circumferential direction. Then, the side of the gaps 14 more inside than the bank 17 is set as a filled recess 18, the both insides 18a and 18b of the filled recess 18 are inclined to be wider outside toward the optical passage hole 3, the bottom surface 18c of the filled recess 18 is inclined obliquely downward from the bank 17 side to the optical passage hole 3, thereby forming the longitudinal section of the filled recess 18 into a rough triangular shape, and the filled recess 18 is filled with adhesive UV to fix the collimator lens QWP to the lens reception seat 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an optical pickup used in, for example, a disk device (DVD recorder, DVD player, etc.), and in particular, can ensure the fixation of a collimating lens with a small amount of adhesive.

Conventionally, there is an optical pickup technique described in Patent Document 1 and the like, and an example thereof will be described with reference to FIG. 4. When an objective lens unit 2 is disposed on an end surface 1 a of a synthetic resin optical base 1, A light passage hole 3 is formed in the optical base 1 so as to face the objective lens unit 2, and a lens seat 4 having a larger diameter and concentric than the light passage hole 3 is integrally formed on the end surface 1 a of the optical base 1. The collimating lens QWP is disposed in the lens seat 4. Reference numeral 5 denotes a rack integrally formed on one side edge of the optical base 1, and the rack 5
The optical base 1 is reciprocated along the radial direction of the disk D by rotating a pinion (not shown) that meshes with the disk D forward and backward.

The objective lens unit 2 is formed on the end surface 1a of the optical base 1 by engaging a projection 6a integrally protruding on the lower surface with a support 1b formed integrally with the end surface 1a of the optical base 1 so as to be swingable. The objective lens OL is disposed in a lens holder 8 that has an act base 6 disposed at a predetermined interval α, and is slidable and swingable along a shaft 7 erected substantially at the center of the act base 6. The focus coil 9 and the magnetic piece 10 are fitted on the boss portion 8a of the lens holder 8, and a tracking coil (not shown) is fixed to the outer surface of the lens holder 8 so that the lens holder 8 is interposed therebetween. A pair of magnets (not shown) are fixed to a pair of left and right side plates that stand from the act base 6. Reference numeral 12 denotes an ultraviolet curable adhesive for fixing the act base 6 to the end face 1 a of the optical base 1.

In the above configuration, the lens holder 8 is applied to the shaft 7 by energizing the focus coil 9 via the printed wiring 11 in a state where the lens holder 8 is floated by the magnetic spring acting between both magnets and the magnetic piece 10. The lens holder 8 is swung in the tracking direction around the shaft by sliding in the focusing directions a and b along the energization of the tracking coil, and the laser beam is emitted from the semiconductor laser (not shown) to the collimating lens QW.
The light is projected onto the disk D through P and the objective lens OL, and information recorded on the disk D is read based on the reflected light.

Conventionally, as an example of a technique for fixing the collimating lens QWP to the lens seat 4, FIG.
There is what is shown in FIG. This is because the lens seat 4 is formed by a plurality (three in this example) of arc pieces 4A arranged in a ring with a gap 14 having a predetermined interval β (for example, 15 ° from the center O of the light passage hole 3) therebetween. The collimating lens QWP is disposed in the lens seat 4, and the gaps 14 are filled with the ultraviolet curable adhesive UV from the nozzle 13 of the adhesive filling device, and the ultraviolet rays are irradiated to irradiate the adhesive UV. By curing, the collimating lens QWP is fixed to the lens seat 4 by three-point adhesion.
JP 2003-317265 A

In the conventional configuration, the materials of the collimating lens QWP (for example, olefin resin) and the material of the optical base 1 (for example, PPS (polyphenylene sulfide)) and the ultraviolet curable adhesive UV are different from each other. When placed in an environment of −20 ° C., the adhesive UV may be peeled off from the collimating lens QWP due to the difference in expansion / contraction ratio of each material, and the adhesive strength to the collimating lens QWP may be reduced.

Therefore, by increasing the opening width t of each gap 14 and setting the opening area (t × h), which is the product of the opening width t and the opening height h, the adhesive UV and the collimating lens QWP.
It is conceivable to widen the contact area with each other, but in this way the opening area (t × h) of each gap 14
Is simply expanded, the volume of each gap 14 is increased by the amount of the spread, and each gap 1 is increased.
4 is filled with a relatively large amount of adhesive UV, and the collimating lens QWP may be distorted or distorted due to curing shrinkage of the relatively large amount of adhesive UV.

Further, since the bottom surface 14a of each gap 14 is horizontal, there is no function of actively flowing the adhesive UV filled on the bottom surface 14a to the collimating lens QWP side, and the filled adhesive UV and the collimating lens QWP There is also a risk that the contact of will be uncertain.

Further, as shown in FIG. 7B, since there is a corner portion between the bottom surface 14a and the inner side surfaces 14b and 14c of each gap 14, the air in the gap 14 is filled when the adhesive UV is filled. May not completely escape and accumulate in the corner portion to form an air reservoir 15. The air reservoir 15 reduces the adhesive force due to the adhesive UV, and the air reservoir 15 expands and contracts due to a temperature change. As a result, distortion and aberration may occur in the collimating lens QWP.

An object of the present invention is to provide an optical pickup capable of reliably fixing a collimating lens with a small amount of adhesive in view of the above-described conventional drawbacks.

In order to achieve the above object, according to the first aspect of the present invention, an objective lens unit is disposed on an end surface of a synthetic resin optical base, and a light passage hole is formed in the optical base facing the objective lens unit. A lens seat made of a plurality of circular arc pieces arranged in an annular shape with a gap of a predetermined interval in between is integrally formed on the end surface of the optical base with a diameter larger than the light passage hole and concentric. A collimating lens is arranged in the seat, and the collimating lens is fixed to the lens seat by filling each gap with an adhesive, and the laser beam is projected onto the disc through the collimating lens and the objective lens of the objective lens unit. In the optical pickup configured to read information recorded on the disk based on the reflected light, the gaps are arranged along the circumferential direction. The weir to be cut is formed integrally with the optical base, the inside of each gap weir is a filling recess, both inner side surfaces of each filling recess are inclined outwardly toward the light passage hole, By inclining the bottom surface obliquely downward from the weir side toward the light passage hole, the vertical cross-sectional shape of each filling recess is formed in a substantially triangular shape, and is formed in an arc shape from both inner side surfaces of each filling recess to the bottom surface By doing so, the cross-sectional shape of each filling recess is formed in a substantially U-shape with a constriction, and by forming an arc shape from both inner side surfaces of each filling recess to the back edge, each filling recess The planar shape is formed in a substantially U shape with a depth,
Each of the filling recesses is filled with an adhesive.

According to a second aspect of the present invention, an objective lens unit is disposed on an end surface of a synthetic resin optical base, and a light passage hole is formed in the optical base so as to face the objective lens unit. A lens seat composed of a plurality of circular arc pieces arranged in an annular shape in between is integrally formed on the end surface of the optical base with a larger diameter and concentric than the light passage hole, and a collimating lens is disposed in the lens seat. The collimating lens is fixed to the lens seat by filling each gap with an adhesive, and the laser beam is projected onto the disc through the collimating lens and the objective lens of the objective lens unit, and based on the reflected light. In an optical pickup that reads information recorded on a disc, a weir that partitions the gaps along the circumferential direction is an optical base. The filling recesses are formed inside the weirs of the gaps, the inner side surfaces of the filling recesses are inclined outwardly toward the light passage hole, and the bottom surfaces of the filling recesses are illuminated from the weir side. By tilting obliquely downward toward the passage hole, the longitudinal cross-sectional shape of each filling recess is formed in a substantially triangular shape, and each filling recess is filled with an adhesive.

According to a third aspect of the present invention, in the second aspect of the present invention, the cross-sectional shape of each filling recess is reduced by forming the filling recess in an arc shape from both inner side surfaces to the bottom surface thereof. Are formed in an arc shape from both inner side surfaces of the respective filling recesses to the back end edge, so that the planar shape of each filling recess is formed into a substantially U-shaped recess. It is characterized by that.

The invention according to claim 1 corresponds to one embodiment (see FIGS. 1 to 3), and according to this, both inner side surfaces of each filling recess are inclined outwardly, The opening width of each filling recess is set wide, and the opening area that is the product of the opening width and the opening height is increased,
Since the longitudinal cross-sectional shape of each filling recess is formed in a substantially triangular shape and the volume thereof is reduced, the filling amount of the adhesive to each filling recess is small for the large opening area, and the small amount of bonding is performed. The collimating lens can be securely fixed by the agent, and the adverse effects caused by the distortion and aberration of the collimating lens due to the curing shrinkage of the adhesive can be extremely reduced.

Further, the bottom surface of each filling recess is inclined obliquely downward from the weir side toward the light passage hole, and the adhesive filled along the inclined bottom surface is actively flowed to the collimating lens side,
The filled adhesive and the collimating lens can be reliably brought into contact with each other, so that the collimating lens can be firmly fixed.

Further, the cross-sectional shape of each filling recess is formed into a substantially U-shape with a concavity, and the planar shape of each filling recess is formed into a substantially U-shape with a concavity, and the inner surface of each filling recess Since there is no equivalent to the conventional rectangular corner portion, when the adhesive is filled, the air in each filling recess is smoothly released along the arcuate inner surface, and in each filling recess An air pocket is not formed as in the prior art. Accordingly, it is possible to solve the problem that distortion and aberration are generated in the collimating lens due to a decrease in the adhesive strength of the adhesive due to the air pool and expansion and contraction due to a temperature change of the air pool.

The invention according to claim 2 corresponds to the basic form, and according to this, both inner side surfaces of each filling recess are inclined outwardly and the opening width of each filling recess is set wide. The opening area, which is the product of the opening width and the opening height, is increased, but the longitudinal sectional shape of each filling recess is formed in a substantially triangular shape and the volume is reduced. However, a large amount of adhesive requires only a small amount of adhesive to be filled into each filling recess, and the small amount of adhesive can securely fix the collimating lens, and distortion and aberration of the collimating lens due to curing shrinkage of the adhesive. The adverse effect due to can be made extremely small.

Further, the bottom surface of each filling recess is inclined obliquely downward from the weir side toward the light passage hole, and the adhesive filled along the inclined bottom surface is actively flowed to the collimating lens side,
The filled adhesive and the collimating lens can be reliably brought into contact with each other, so that the collimating lens can be firmly fixed.

According to the third aspect of the present invention, the cross-sectional shape of each filling recess is formed into a substantially U-shaped recess, and the planar shape of each filling recess is formed into a substantially U-shaped recess. In addition, since there is no equivalent to the conventional square corner portion on the inner surface of each filling recess, the air in each filling recess escapes smoothly along the arc-shaped inner surface when the adhesive is filled. Thus, an air pocket is not formed in each filling recess as in the prior art. Accordingly, it is possible to solve the problem that distortion and aberration are generated in the collimating lens due to a decrease in the adhesive strength of the adhesive due to the air pool and expansion and contraction due to a temperature change of the air pool.

1 to 3 show the main part of an optical pickup according to an embodiment of the present invention.
A weir 17 for partitioning the gap 14 between the arc pieces 4A forming the lens seat 4 along the circumferential direction is formed integrally with the optical base 1, and the inside of the weir 17 of each gap 14 is a filling recess 18; Both inner side surfaces 18a and 18b of each filling recess 18 are inclined outwardly toward the light passage hole 3,
By inclining the bottom surface 18c of each filling recess 18 obliquely downward from the upper end surface of the weir 17 toward the light passage hole 3, the vertical cross-sectional shape of each filling recess 18 is formed in a substantially triangular shape [FIG.
a)], by forming an arc shape from both inner side surfaces 18a, 18b of each filling recess 18 toward its bottom surface 18c, each filling recess 18 has a substantially U-shaped cross section. Formed (see FIG. 3 (b)) and formed in an arc shape from both inner side surfaces 18a, 18b of each filling recess 18 to the back end edge 18d, the planar shape of each filling recess 18 is reduced. (See FIG. 3C). Since the configuration other than the above is substantially the same as the configuration shown in FIGS.

The fixing procedure of the collimating lens QWP will be described. The collimating lens QWP is arranged in the lens seat 4, and the ultraviolet curable adhesive UV is filled into each filling concave portion 18 from the nozzle 13 of the adhesive filling device and irradiated with ultraviolet rays. Then, by curing the adhesive UV, the collimating lens QWP is fixed to the lens seat 4 by three-point adhesion.

According to the above configuration, as shown in FIG. 2, both inner side surfaces 18 a, 18 b of each filling recess 18 formed inside the weir 17 of each gap 14 are inclined so as to spread outwardly, and each filling recess 18 Is set to be wide, and the opening area (t × h) is the product of the opening width t and the opening height h.
However, as shown in FIG. 3A, the longitudinal sectional shape of each filling recess 18 is formed in a substantially triangular shape and its volume is reduced, so that the opening area (t × h) However, the amount of the adhesive UV filled in each filling recess 18 is small, and the collimating lens QWP can be securely fixed by the small amount of adhesive UV, and the collimation due to the curing shrinkage of the adhesive UV can be achieved. The adverse effects due to distortion and aberration of the lens QWP can be extremely reduced.

Further, as shown in FIG. 3A, the bottom surface 18c of each filling recess 18 is inclined obliquely downward from the weir 17 side toward the light passage hole 3, and the filled adhesive is filled along the inclined bottom surface 18c. Since the agent UV is actively flowed to the collimating lens QWP side, the filled adhesive UV and the collimating lens QWP can be reliably brought into contact with each other to firmly fix the collimating lens QWP.

Further, as shown in FIG. 3 (b), the cross-sectional shape of each filling recess 18 is formed in a substantially U-shape with a concavity, and the plane of each filling recess 18 is shown in FIG. 3 (c). Each of the filling recesses 18 is formed when the adhesive UV is filled because the inner surface of each filling recess is not substantially equivalent to a conventional corner corner. The air inside is smoothly released along the arc-shaped inner side surfaces 18a and 18b, and the air reservoir 15 (see FIG. 7B) is not formed in each filling recess 18 as in the prior art. Accordingly, the collimating lens Q is caused by the expansion and contraction caused by the adhesive strength reduction of the adhesive UV due to the air reservoir 15 and the temperature change of the air reservoir 15.
The difficulty that distortion and aberration occur in WP can be solved.

It is a top view which shows the principal part of the optical pick-up which is one Embodiment of this invention. It is an expansion perspective view of the principal part. (A) is an AA arrow view of FIG. 1, (b) is a BB arrow view, (c) is CC arrow view. It is a longitudinal cross-sectional view which shows an optical pick-up. It is a top view of the principal part which shows a prior art example. It is an expansion perspective view of the principal part. (A) is a DD arrow view of FIG. 5, (b) is an EE arrow view, (c) is an FF arrow view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optibase 2 Objective lens unit 3 Light passage hole 4 Lens seat 4A Arc piece 14 Space | gap 17 Weir 18 Filling recessed part 18a, 18b Inner side surface of filling recessed part 18c Bottom face of filling recessed part QWP Collimating lens UV UV curable adhesive

Claims (3)

The objective lens unit is disposed on the end face of the synthetic resin optical base, and a plurality of light passing holes are formed in the optical base so as to face the objective lens unit, and are arranged in an annular shape with a predetermined gap therebetween. A lens seat having a diameter larger than that of the light passage hole and concentrically formed on the end surface of the optical base, a collimator lens is disposed in the lens seat, and an adhesive is provided in each gap. The collimating lens is fixed to the lens seat by filling, and the laser beam is projected onto the disc through the collimating lens and the objective lens of the objective lens unit, and the information recorded on the disc is read based on the reflected light. In the optical pickup configured as described above, a weir for partitioning the gaps along the circumferential direction is formed integrally with the optical base. Inside the weir is a filling recess, both inner side surfaces of each filling recess are inclined outwardly toward the light passage hole, and the bottom surface of each filling recess is inclined obliquely downward from the weir side toward the light passage hole By inclining, the vertical cross-sectional shape of each filling recess is formed in a substantially triangular shape, and by forming an arc shape from both inner side surfaces to the bottom surface of each filling recess,
The cross-sectional shape of each filling recess is formed in a substantially U-shape with a concavity, and by forming an arc shape from both inner side surfaces to the back end edge of each filling recess, the planar shape of each filling recess is An optical pickup which is formed in a substantially U-shaped concavity and each filling recess is filled with an adhesive. The objective lens unit is disposed on the end face of the synthetic resin optical base, and a plurality of light passing holes are formed in the optical base so as to face the objective lens unit, and are arranged in an annular shape with a predetermined gap therebetween. A lens seat having a diameter larger than that of the light passage hole and concentrically formed on the end surface of the optical base, a collimator lens is disposed in the lens seat, and an adhesive is provided in each gap. The collimating lens is fixed to the lens seat by filling, and the laser beam is projected onto the disc through the collimating lens and the objective lens of the objective lens unit, and the information recorded on the disc is read based on the reflected light. In the optical pickup configured as described above, a weir for partitioning the gaps along the circumferential direction is formed integrally with the optical base. Inside the weir is a filling recess, both inner side surfaces of each filling recess are inclined outwardly toward the light passage hole, and the bottom surface of each filling recess is inclined obliquely downward from the weir side toward the light passage hole An optical pickup characterized in that, by inclining, the longitudinal sectional shape of each filling recess is formed in a substantially triangular shape, and each filling recess is filled with an adhesive. By forming an arc shape from both inner side surfaces to the bottom surface of each filling recess, the cross-sectional shape of each filling recess is formed into a substantially U-shape with a concavity. 3. The optical pickup according to claim 2, wherein the planar shape of each filling recess is formed in a substantially U-shape with a depth by forming an arc shape over the end edge.

Images