JP2002022907A5 - Optical pickup device provided with plastic lens and method of molding plastic lens - Google Patents

Description

[0001]
Field of the Invention
The present invention relates to an optical pickup device provided with a plastic lens formed by injection molding, and a molding method of the plastic lens, and more particularly, to an optical pickup device provided with a plastic lens having small positive power and a molding method of the plastic lens.

  Therefore, according to the present invention, it is possible to obtain good optical performance with excellent transferability, and it is possible to suppress the product cost without requiring time for injection molding, and to mold the optical pickup device and the plastic lens The task is to provide a method.

[0006]
[Means for Solving the Problems]
The above-mentioned subject is formed of a norbornene-based or amorphous polyolefin-based material by injection molding, and the minimum thickness T (mm) located between the flange portion and the lens portion is 0.7 mm or less. Or a plastic having a positive power and a minimum thickness T (mm) located between the flange portion and the lens portion of 0.7 mm or less. It can be solved by a method of molding a plastic lens, which is a method of molding a lens, and injection molding is performed using a norbornene-based or amorphous polyolefin-based material.

[0027]
【Effect of the invention】
As described above, according to the present invention, it is possible to obtain good optical performance with excellent transferability, and to use plastic lens with positive power which can suppress the product cost without requiring time for injection molding. And a method of molding a plastic lens.

Claims (13)

A plastic lens formed of a norbornene-based or amorphous polyolefin-based material by injection molding, having a minimum thickness T (mm) located between the flange portion and the lens portion of 0.7 mm or less and having a positive power An optical pickup device comprising: The optical pickup device according to claim 1, wherein the plastic lens is made of a material having a specific gravity of 1.1 or less. The plastic lens according to claim 1 or 2, wherein when the retardation distribution is measured from the direction parallel to the optical axis, assuming that the maximum retardation is δ, δ <| 50 ° | Optical pickup device . The plastic lens satisfies R1 / R2 <-0.26 when the radius of curvature near the optical axis is R1 and R2 (where R1> R2). The optical pickup device described in one. The optical pickup according to any one of claims 1 to 4, wherein the plastic lens satisfies T / D <0.4 when the thickness on the optical axis is D (mm). Device . The optical pickup device according to any one of claims 1 to 5, wherein the plastic lens is an objective lens. The optical pickup device according to any one of claims 1 to 5, wherein the plastic lens is a collimator lens. The optical pickup device according to any one of claims 1 to 7, further comprising an actuator. 9. The optical pickup device according to claim 8, wherein the plastic lens is mounted on the actuator. The optical pickup device according to any one of claims 1 to 9, wherein the plastic lens is formed by pouring the material from a gate portion provided in the flange portion. The optical pickup device according to any one of claims 1 to 10, wherein the plastic lens is a biconvex positive lens. A method of molding a plastic lens having a positive power, wherein the minimum thickness T (mm) located between the flange portion and the lens portion is 0.7 mm or less,
A molding method of a plastic lens characterized by performing injection molding with a norbornene-based or amorphous polyolefin-based material. The method for forming a plastic lens according to claim 12, wherein the material is poured from a gate portion provided in the flange portion.