JPH0328684B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic lens having a shape that allows the lens itself to be assembled without using a lens frame when assembling the lens system.

When assembling a lens system, it is necessary to accurately adjust and maintain the alignment of the optical axes of the lenses, the direction of rotation about the optical axis, the parallelism in the direction perpendicular to the optical axis, and the interval dimension. For this reason, accuracy is maintained through the lens frame by precisely machining the inner diameter and abutting portion of the lens frame and holding the lens therein. Conventionally, plastic lenses have generally been assembled using the same assembly method as glass lenses.

However, when a mirror frame is used, the external size becomes larger,
Not only is this a major obstacle to making the lens system more compact, but the number of parts is usually several more than the number of lenses, which tends to increase costs. In terms of accuracy,
The number of intermediary parts and intermediary locations that affect the accuracy between lenses increases, making it difficult to maintain accuracy. Further, the accuracy of fitting with the lens frame varies depending on the external shape of the lens, and it is much more difficult to maintain accuracy with square, rectangular, elliptical, rhomboid, etc. lenses than with circular lenses.

In the present invention, a tangential surface for lens assembly is integrally molded on the outside of the effective surface of a plastic lens, and a convex portion or a recessed portion for positioning that engages with another lens is provided on the tangential surface, and the lens The objective is to assemble the plastic lens precisely and compactly by engaging and integrating the parts.

A detailed explanation will be given below with reference to the drawings.

FIG. 1 is a sectional view of a lens barrel showing a conventional method of assembling a lens system.
The outer peripheries of lenses 1, 2, 3, and 4 are engaged with d, respectively, to align the optical axes and determine and maintain the rotation direction around the optical axis. Lenses 2 and 3 abut against 5e and 5f of the lens frame, and the spacers Lenses 3 and 4 on 7a and 7b of 7
The lens 1 is in contact with the presser ring 6.
Therefore, the assembly accuracy of the lens is affected not only by the processing accuracy of each engaging portion of the lens frame 5, the spacer 7, and the presser ring 6, but also by the attachment accuracy of the spacer 7 and the presser ring 6 to the lens frame 5.

FIG. 2 shows a square plastic lens as an embodiment of the present invention. To the effective surfaces 11 and 12 of the lens, tangential surfaces 13 at four corners protrude outward from the lens surfaces in the optical axis direction.
and 14 are molded integrally with the lens, and a convex portion 15 or a concave portion 16 for positioning that engages with another lens is provided thereon.

FIG. 3 is a sectional view showing an example of the case where the plastic lenses of the present invention as described above are assembled and engaged with each other, and FIG. Examples will be shown in which the present invention is applied to lenses of various shapes.

In these embodiments, the tangential planes 13 all protrude in the optical axis direction beyond the lens surface, but the present invention is not limited to this; for example, the first
In cases such as the engagement of lenses 3 and 4 in the figure, the fifth
As shown in the figure, the tangential plane 13' is naturally located inward in the optical axis direction with respect to the lens surface 11'.

Since the present invention has the above configuration, it has the following remarkable effects.

There is no need for anything equivalent to a lens frame, and the lens system can be assembled with a minimum number of parts and minimum external dimensions.

Since the tangential plane is molded integrally with the lens, assembly accuracy is good and manufacturing costs can be reduced.

Since the tangential plane and the positioning convex portion protrude in the optical axis direction beyond the effective surface of the lens, they can be handled without damaging the effective surface of the lens.

Since the tangential plane is provided outside the effective surface of the lens, the outer shape can be maintained without touching the effective surface of the lens during the assembly process. This has a great effect when automating assembly.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a known lens assembly, FIG. 2 is a plan view and a cross-sectional view of an embodiment of the plastic lens of the present invention, FIG. 3 is a cross-sectional view of the lens assembly of the present invention, and FIG. 5 is a plan view and a partially sectional side view of another embodiment, FIG. 5 is a side view of still another embodiment,
1, 2, 3, 4: Lens, 5: Mirror frame, 13, 1
4: Tangent plane, 15: Engagement protrusion, 16: Engagement recess.

Claims (1)

[Claims] 1. A plastic lens in which a tangential plane for assembling the lens is molded integrally with the lens outside the effective surface of the lens, and a convex part or a concave part for positioning that engages with another lens is provided on the tangential plane. .