JPH10268109A - Compound lens and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly and accurately mount a compound lens on a lens holder, and reduce manufacturing cost by integrating a lens mounting flange with the synthetic resin layer of the compound lens. SOLUTION: A synthetic resin layer 15 having a micro Fresnel lens 15a is bonded to one side of a glass substrate 11, thereby forming a compound lens 10. Also, a flange 15b is jointed to the periphery of the glass substrate 11 for mounting the compound lens 10 on a lens holder 30. In this case, the flange 15b is formed as integral part of the synthetic resin layer 15, when this synthetic resin layer 15 is jointed to the glass substrate 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compound lens and a method for manufacturing the same, and more particularly, to a compound lens used for an optical pickup for reading information such as a CD and a DVD, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In an optical pickup for reading information such as a CD or DVD, a compound aspherical lens in which a synthetic resin layer is bonded to one surface of a glass substrate is sometimes used as an objective lens. . This compound lens is mounted on a lens holder provided in a biaxial device of an optical system.

[0003]

However, in the case of the conventional compound lens 1 as shown in FIG. 4, since the outer peripheral portion of the compound lens 1 also has a lens surface, the compound lens 1 is attached to the lens holder 30. When mounted, the lens surface comes into direct contact with the lens holder 30, and the surface of the synthetic resin layer 15 bonded to the glass substrate 11 may be damaged.

Further, in the conventional compound lens 1, since the lens surface which is a curved surface and the lens holder 30 are in direct contact with each other,
The contact area between the compound lens 1 and the lens holder 30 was small, and lacked stability when the compound lens was mounted. Therefore, as shown by the dotted line in FIG. 4, the lens may be mounted while being tilted, and the optical axis is tilted,
There is also a problem that the reading performance is deteriorated or the reading becomes impossible in some cases.

In this case, for example, it is conceivable to form a composite lens by bonding a synthetic resin layer to a glass substrate having an outer peripheral portion formed in a brim shape. However, after grinding and polishing the glass substrate, Since a step of pressing at a high temperature is required, the production cost of the compound lens increases.

Accordingly, an object of the present invention is to provide a compound lens which can be manufactured inexpensively and in large quantities, and which can be securely and accurately mounted on a lens holder, and a method of manufacturing the same.

[0007]

A composite lens according to the present invention is mounted on an optical lens holder, and is formed by bonding a synthetic resin layer to one surface of a glass substrate. It is formed integrally and has a flange portion for mounting on a lens holder.

The external shape of the flange portion is substantially the same as the internal shape of the lens holder on which the compound lens is mounted. Accordingly, the contact area between the compound lens and the lens holder when the compound lens is mounted on the lens holder is increased, and the stability when the compound lens is mounted on the lens holder is improved.

A method of manufacturing a composite lens according to the present invention is a method of manufacturing a composite lens mounted on an optical lens holder by bonding a synthetic resin layer to one surface of a glass substrate. It is characterized in that a flange portion for causing the flange is formed integrally with the synthetic resin layer.

In this case, a mold having a lens molding surface opposite to the surface to be formed on the synthetic resin layer and a flange molding surface formed around the lens molding surface is used. The synthetic resin is poured into the mold, the glass substrate is overlaid, and the synthetic resin is cured, whereby the flange portion is formed integrally with the synthetic resin layer. No special processing on the glass substrate is required to form the flange portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a compound lens according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing a state in which a compound lens 10 according to a first embodiment of the present invention is mounted on a lens holder 30 provided in a biaxial device of an optical pickup for reading information such as a CD and a DVD. FIG. Here, a storage medium such as a CD is located on the upper side in the figure, and a light source is located on the lower side.

The composite lens 10 comprises a glass substrate 11 and a synthetic resin layer 15 made of an energy-curable resin or the like joined to one surface of the glass substrate 11. In the composite lens 10, the lens surface of the glass substrate 11 is located on the upper side in FIG. 1, that is, on the storage medium side, and the synthetic resin layer 15 is located on the lower side in FIG.
It is mounted on the lens holder 30 so as to be located on the light source side.

The surface 11a of the glass substrate 11 is polished to a desired spherical surface in advance, and the surface 11b is polished to a curved surface similar to the surface to be formed by the synthetic resin layer 15.
The synthetic resin layer 15 bonded to the glass substrate 11 includes:
Micro Fresnel 1 around the optical axis of compound lens 10
5a are formed.

Further, a flange-like flange portion 15b is joined along the outer peripheral portion of the glass substrate 11. The flange portion 15b is formed integrally with the synthetic resin layer 15, and does not require any special processing on the glass substrate 11 when forming the flange portion 15b. Therefore, the manufacturing cost of the compound lens 10 can be reduced.

The outer diameter of the flange portion 15b is substantially the same as the inner diameter of the lens mounting opening 30a of the lens holder 30. The lower surface 15c of the flange portion 15b is flat, and has a width substantially equal to the width of the support surface 30b of the lens mounting opening 30a. That is, since the outer shape of the flange 15b is substantially the same as the inner shape of the opening 30a of the lens holder 30, the flange 15b can be fitted into the opening 30a of the lens holder 30. As a result, the composite lens 10 is
When mounted on the lower surface, the lower surface 15c of the flange portion 15b and the support surface 30b of the opening 30a of the lens holder come into surface contact with the outer peripheral surface of the flange portion 15b and the inner peripheral surface of the opening 30a. growing. Therefore, the stability when the compound lens 10 is mounted on the lens holder is improved, and it is possible to prevent the lens from being mounted while being tilted.

FIG. 2 is a cross-sectional view showing a state in which a compound lens 10 ′ according to a second embodiment of the present invention is mounted on a lens holder 30. The composite lens 10 shown in FIG.
The same members as those described above are denoted by the same reference numerals and described.

The composite lens 10 'shown in FIG. 1 has a synthetic resin layer 15 bonded only on the surface 11b of the glass substrate 11, and a flange portion 15d formed integrally with the synthetic resin layer 15 has a glass base. It is different from the complex lens 10 shown in FIG. 1 in that it does not extend to the outer peripheral portion of the material 11.

In this case, the outer diameter of the glass substrate 11 is substantially the same as the inner diameter of the lens mounting opening 30a of the lens holder 30. The lower surface 15e of the flange portion 15d is flat, and the support surface 30 of the lens mounting opening 30a is formed.
It has a width substantially the same as the width of b.

When the compound lens 10 'is mounted on the lens holder 30, the lower surface 15e of the flange 15d and the support surface 30b of the opening 30a of the lens holder, and the outer peripheral surface of the flange 15d and the glass substrate 11 30a
Is in surface contact with the inner peripheral surface.

In the second embodiment, since the outer peripheral surface of the glass substrate 11 also functions as a contact surface when the composite lens 10 'is mounted on the lens holder 30, the outer peripheral surface of the glass substrate 11 is different from that of the composite lens 10 shown in FIG. Thus, the amount of the synthetic resin can be reduced.

Incidentally, the shape of the flange portions 15b and 15e can be set to any shape according to the shape of the lens holder on which the compound lens is to be mounted.

In the above-described embodiment, the synthetic resin layer bonded to the glass substrate 11 is one layer. However, the present invention is not limited to this. The first layer made of a resin may be covered with a second layer made of a synthetic resin having high weather resistance and high hardness. In this case, the flange portion may be formed integrally with any of the first and second layers.

FIG. 3 is a sectional view showing a mold 50 for manufacturing the compound lens 10 according to the present invention. The mold 50 is manufactured by mirror-cutting and polishing a metal such as stainless steel / electroless Ni.

The lens molding surface 51 of the mold 50 is formed so as to have a surface opposite to the surface of the synthetic resin layer bonded onto the glass substrate 11, and a micro Fresnel molding surface 51a is formed at the center thereof. Is formed. The micro Fresnel molding surface 51a is formed so as to be opposite to the micro Fresnel of the synthetic resin layer.

Further, at least three projections 53 are provided on the lens molding surface 51, and the height of the projections 53 determines the thickness of the synthetic resin layer of the composite lens.

Further, flange molding surfaces 51b and 51c are formed around the lens molding surface 51. The flange portion forming surface 51b is a flat surface, and its width is substantially the same as the width of the support surface at the opening of the lens holder where the compound lens is to be mounted. Further, the flange portion forming surface 51c has a cylindrical surface, and the inner diameter thereof is substantially the same as the inner diameter of the opening of the lens holder in which the compound lens is to be mounted.

The shape of the flange forming surfaces 51b and 51c can be any shape according to the shape of the lens holder on which the compound lens is to be mounted.

Next, a method of manufacturing the compound lens 10 according to the present invention using the above-described mold 50 will be described.

First, a predetermined amount of a semi-polymer of a synthetic resin such as an energy irradiation-curable resin, which is a raw material of a synthetic resin layer, is poured onto a mold 50 controlled at a predetermined temperature.

Next, the glass substrate 11 is overlaid on the synthetic resin and pressed against the mold. Thereby, the center of the glass substrate 11 and the center of the mold coincide, and the thickness of the synthetic resin layer is set to a predetermined thickness. At this time, the synthetic resin uniformly flows into the micro Fresnel molding surface 51b of the mold 50 and also flows into the flange molding surfaces 51b and 51c.

Further, in a state where the glass substrate 11 is pressed, the synthetic resin in a semi-polymerized state sandwiched between the glass substrate 11 and the mold 50 is passed through the glass substrate 11, for example, Ultraviolet rays and an electron beam are irradiated, and at the same time, the semi-polymerized synthetic resin flowing into the flange forming surfaces 51b and 51c is irradiated with an ultraviolet ray or the like to complete the polymerization. Thereby, the flange portion is formed integrally with the synthetic resin layer. Here, the flange portion forming surface 51b,
Since the upper part of the composite lens 51c is open, the synthetic resin forming the flange of the compound lens is cured without exceeding the height of the flange molding surface 51c.

After the synthetic resin has cured, the composite lens 10 is removed from the mold, and the production of the composite lens is completed.

[0034]

According to the present invention, since the flange portion for mounting on the lens holder to which the compound lens is to be mounted is formed integrally with the synthetic resin layer, the lens does not require any special processing on the glass substrate. It is possible to provide a large number of inexpensive and complex lenses that can be reliably and accurately mounted on a holder.

Further, since the shape of the flange is substantially the same as the internal shape of the lens holder, the contact area between the flange and the opening of the lens holder becomes large when the compound lens is mounted on the lens holder. Thereby, stability when the compound lens is mounted on the lens holder is improved. In addition, since it is possible to prevent the lens from being mounted while being tilted, problems such as deterioration of reading performance due to tilting of the optical axis and inability to read are not caused.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state where a compound lens according to a first embodiment of the present invention is mounted on a lens holder.

FIG. 2 is a cross-sectional view showing a state where a compound lens according to a second embodiment of the present invention is mounted on a lens holder.

FIG. 3 is a cross-sectional view showing a mold for manufacturing the compound lens according to the present invention.

FIG. 4 is a cross-sectional view showing a state in which a conventional compound lens is mounted on a lens holder.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Composite lens, 11 ... Glass base material, 15 ... Synthetic resin layer, 15a ... Micro Fresnel, 15b, 15d ... Flange part, 30 ... Lens holder, 50 ... Mold, 51 ... Lens molding surface, 51a ... Micro Fresnel molding Face, 51
b, 51c: Flange molding surface

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kengi Yagi 1-324 Uetakecho, Omiya City, Saitama Prefecture Fuji Photo Optical Co., Ltd.

Claims (2)

[Claims] 1. A composite lens which is mounted on an optical lens holder and has a synthetic resin layer bonded to one surface of a glass substrate, wherein the composite lens is formed integrally with the synthetic resin layer. A compound lens having a flange portion for mounting. 2. A method of manufacturing a composite lens to be mounted on a lens holder of an optical system by bonding a synthetic resin layer to one surface of a glass substrate, wherein the flange for mounting on the lens holder is formed by the synthetic method. A method for manufacturing a compound lens, wherein the compound lens is formed integrally with a resin layer.