JP2001350074A - Lens-attaching structure for optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely fix a lens to a lens holder by holding force, which is always uniform and also to prevent the occurrence of the distortion of the lens due to tensile stresses, even in the case of fixing the lens whose outside diameter is small. SOLUTION: In the lens-attaching structure of an optical pickup, by which the lens 14 is fitted in a lens-attaching hole 12 provided at the lens holder 11 and the outer peripheral part of the lens 14 is fixed at the lens holder 11, a projected part 13 is provided at the peripheral edge of the lens-attaching hole 12, and it is caulked thermally at a caulking margin 15, provided at the outer peripheral part of the lens 14. The lens 14 caulked thermally is held by uniform caulking force over the entire periphery, so that the fixing force of the lens 14 is stabilized and the variation in the quality of a product hardly occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens mounting structure used for an optical pickup mechanism or the like.

[0002]

2. Description of the Related Art Conventionally, an optical pickup mechanism has been used for a compact disk, a magneto-optical disk, a DVD player, and the like. As shown in FIGS. 5 and 6, this optical pickup mechanism incorporates a lens 2 for focusing a laser beam on a lens holder 1. Conventionally, a lens mounting hole 3 for fitting the lens 2 into the lens holder 1 is opened, and the lens 2 is inserted into the lens mounting hole 3.
Was fitted and fixed. That is, the step portion 4 is provided along the inner peripheral surface of the lens mounting hole 3 while the lens 2
A margin 5 is provided on the outer peripheral portion of the substrate, and the margin 5 is placed on the step portion 4.
The adhesive 6 is dropped, and the UV adhesive 6 is temporarily cured by irradiating ultraviolet rays. Next, a large number of these are arranged on a pallet (not shown), placed in a curing furnace, and irradiated with ultraviolet rays again to completely cure the UV adhesive 6, and the lens 2 is placed on the lens holder 1.
Was fixed.

[0003]

However, in the above-mentioned conventional means for fixing the lens 2 using the UV adhesive 6, it is difficult to quantitatively control the drop of the UV adhesive 6, and if the amount of drop is different, In addition to the fact that the entire circumference of the lens 2 cannot be fixed with a uniform adhesive force, when the amount of dripping is too large, there is a problem that liquid dripping occurs and the adhesive 2 protrudes from the margin 5 to the lens side. Especially under the rapid innovation of recent times,
As the amount of data increases, the density of the entire apparatus is required, and the outer dimensions of the lens 2 tend to be smaller. Therefore, the width of the bonding margin 5 of the lens 2 is also gradually decreasing. As a result, even a slight dripping of the UV adhesive 6 adversely affects the lens 2.

Further, in the work process, there is a problem that work management is difficult, such as generation of bubbles from the UV adhesive 6 and change in the amount of ultraviolet light due to deterioration of the irradiation lamp and the optical fiber.

[0005] In addition, the above fixing means requires a step of temporarily curing the UV adhesive 6 and a step of fully curing the UV adhesive 6, so that the fixing operation of the lens 2 takes time. There was a problem.

Further, when the UV adhesive 6 is cured, a tensile stress is generated.
May cause distortion. In particular, if the external dimensions of the lens 2 itself become smaller, the focal length becomes shorter.
Even a slight distortion of the lens 2 greatly affects the accuracy of the optical pickup.

In view of the above, the present invention not only fixes the lens with a uniform holding force to the lens holder and reliably, but also prevents the occurrence of lens distortion due to tensile stress even when fixing a lens having a small external dimension. It is an object of the present invention to provide a lens mounting structure for an optical pickup that prevents the optical pickup and allows the lens to be fixed in a short time.

[0008]

According to a first aspect of the present invention, there is provided a lens mounting structure for an optical pickup, wherein a lens is fitted into a lens mounting hole provided in a lens holder. In the lens mounting structure of the optical pickup in which the outer peripheral portion is fixed to the lens holder, the peripheral edge of the lens mounting hole is caulked to the outer peripheral portion of the lens.

According to the present invention, since the lens mounting hole can be fixed with a uniform holding force by caulking the peripheral edge of the lens mounting hole to the outer peripheral portion of the lens, there is no need to perform quantitative control of the UV adhesive as in the related art. In addition, even when fixing a very small lens having a small external dimension, there is no danger of causing a dripping of the UV adhesive and poor adhesion as in the conventional case, and the lens is distorted because the lens is merely crimped. Nothing.

According to a second aspect of the present invention, in the lens mounting structure for an optical pickup according to the first aspect, a protrusion is provided on a peripheral edge of the lens mounting hole, and the protrusion is crushed while being heated, and the outer periphery of the lens is crushed. It is characterized by heat caulking the part.

[0011] The invention of claim 3 is the invention according to claim 1 or 2.
The lens mounting structure for an optical pickup according to the above, wherein a caulking is provided on an outer peripheral portion of the lens.

According to the second and third aspects of the present invention, it is possible to heat the outer peripheral portion of the lens simply by crushing the protrusion provided on the peripheral edge of the lens mounting hole while heating.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lens mounting structure for an optical pickup according to the present invention will be described below in detail with reference to the accompanying drawings. Here, FIG. 1 is a perspective view showing a relationship between a lens and a mounting hole formed in the lens holder, and FIG. 2 is a cross-sectional view when a lens is fitted into the mounting hole. FIG.
FIG. 4 is a conceptual view of a heat caulking device used in this embodiment, and FIG. 4 is a cross-sectional view showing a state in which the periphery of the mounting hole is thermally deformed to the outer peripheral portion of the lens.

In FIGS. 1 and 2, the lens holder 11 is provided with a circular lens mounting hole 12 as in the prior art, and the periphery of the lens mounting hole 12 slightly projects from the upper surface of the lens holder 11. A ring-shaped projection 13 is formed all around. The projection 13 is integrally formed when the lens holder 11 is formed, and has a mountain-shaped cross section as shown in FIG. In addition, a step portion 16 on which the caulking margin 15 of the lens 14 to be described later is placed is formed on the inner peripheral surface of the lens mounting hole 12 so as to protrude inward. The protrusion width dimension w1 of the step portion 16 is as described above. The projection width w2 of the stepped portion 4 in the conventional lens mounting hole 3 is smaller than w2.

The lens 14 fitted into the lens mounting hole 12 is a plastic convex lens having a small external dimension as shown in FIGS. This lens 1
The outer periphery of 4 is provided with a caulking margin 15 projecting outwardly over the entire circumference, and the protruding width of the caulking margin 15 is
It is formed to be narrower than the bonding margin 5 of the conventional lens 2 described above.

FIG. 3 shows a table-top type heat staking device 2 for squeezing a projection 13 provided on the peripheral edge of the lens mounting hole 12 while heating and squeezing the staking portion 15 of the lens 14.
0 is an example. This heat caulking device 20
Are the control unit 21 and the tower unit 2
And a horn unit 24 attached to the tower unit 22 so as to be able to move up and down. The control unit 21 includes servomotors 25 and electrical components such as a computer 26 for controlling the servomotors. It is built-in. Further, a fixing jig 27 is mounted on the upper surface of the control unit 21, and a display unit 28 is provided on the front surface. Tower unit 22
A ball screw 29 that is rotated by the drive of the servo motor 25 is vertically long, and a nut portion 30 of the horn unit 24 is attached to the ball screw 29 via a ball bearing (not shown). . On the front of the tower unit 22, an operation panel 31 for setting numerical values of caulking conditions and the like using ten keys is provided.
Is provided.

A movable jig 32 is detachably provided on the lower surface of the horn unit 24, and a heater and a heat insulating material (both not shown) are built in the upper part of the movable jig 32. When caulking, the movable jig 32 is heated by the heater.
Is heating. A work holder (not shown) for fixing the work so as not to move when pressurized is arranged at the center of the horn unit 24.

Next, the heat caulking device 20 having the above-described structure
The process in the case where the lens 14 is heat-swaged to the lens holder 11 by using will be described. First, as shown in FIGS. 2 and 3, the lens holder 11 is set on the fixing jig 27 of the heat caulking device 20, and the lens 1 is inserted into the lens mounting hole 12 from above.
Insert 4. Next, when the start button of the heat caulking device 20 is pressed, the servomotor 25 is driven based on a preset numerical value, and the movable jig 32 is lowered to heat the projection 13 on the peripheral edge of the lens mounting hole 12. Press gradually. When the protrusion 13 is gradually crushed and a predetermined pressure is detected, the movable jig 32 stops at that position for a predetermined time and holds the pressure. As a result, as shown in FIG.
The top of the protrusion 13 is crushed inward, and the crimping margin 15 provided around the lens 14 is pressed down with a uniform crimping force over the entire circumference to fix the lens 14. When the heat staking is completed, the movable jig 32 is raised, and a new lens holder 11 is set on the fixed jig 27.

The lens 14 that has been heat-sealed to the lens holder 11 is firmly fixed at a predetermined mounting position, and is held with a uniform crimping force over the entire circumference. It is stable and there is almost no variation in quality when commercialized. Further, since tensile stress does not act on the lens 14 unlike the UV adhesive, the lens 1 is not affected by thermal expansion or thermal contraction of the lens holder 11.
4 has little effect, thereby preventing the lens 14 from being distorted.

In the above embodiment, the lens mounting hole 1
Although the case where the ring-shaped projection 13 is provided on the entire periphery of 2 and the entire periphery of the caulking margin 15 is heat caulked has been described,
The present invention includes a case where a protrusion is partially provided on the periphery of the lens mounting hole 12 and the protrusion is heat-sealed. Further, in the above embodiment, the case where the caulking margin 15 is provided on the outer peripheral portion of the lens 14 has been described. However, by minimizing the amount of thermal deformation of the peripheral edge of the lens mounting hole 12, the caulking margin 15 can be omitted. It is also possible to heat the lens 14 without affecting the lens 14.

[0021]

As described above, according to the lens mounting structure of the optical pickup according to the present invention, the peripheral edge of the lens mounting hole can be fixed with a uniform holding force by caulking the peripheral edge of the lens. It is not necessary to perform the quantitative control of the UV adhesive as in the related art, and a predetermined quality can be ensured by a simple mounting method. In addition, even when fixing an extremely small lens with small external dimensions, there is no danger of liquid dropping of the UV adhesive or poor adhesion as in the past, and since the lens is simply crimped, it is difficult to pull No stress acts on the lens, and no distortion occurs in the lens due to thermal expansion or contraction of the lens holder. Further, the fixing operation of the lens can be performed in a very short time as compared with the conventional fixing means.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a lens mounting structure of an optical pickup according to the present invention.

FIG. 2 is a cross-sectional view showing a state before the lens is heated by heat.

FIG. 3 is a side view showing an outline of a heat caulking device that can be used in the present invention.

FIG. 4 is a cross-sectional view showing a state after the lens is heat-sealed.

FIG. 5 is a perspective view showing a lens mounting structure of a conventional optical pickup.

FIG. 6 is a cross-sectional view showing a state where the lens is fixed with a UV adhesive.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Lens holder 12 Lens mounting hole 13 Projection part 14 Lens 15 Swage

Claims (3)

[Claims] 1. A lens mounting structure for an optical pickup in which a lens is fitted into a lens mounting hole provided in a lens holder and an outer peripheral portion of the lens is fixed to the lens holder, wherein a peripheral edge of the lens mounting hole is provided on an outer peripheral portion of the lens. A lens mounting structure for an optical pickup characterized by being crimped. 2. A lens mounting for an optical pickup according to claim 1, wherein a projection is provided on a peripheral edge of said lens mounting hole, and said projection is crushed while being heated to heat the outer circumference of the lens. Construction. 3. A lens mounting structure for an optical pickup according to claim 1, wherein a caulking margin is provided on an outer peripheral portion of said lens.