Lens unit having a plurality of plastic lenses, and optical device

Patent metadata

Field	Value
Publication number	US-2016147033-A1
Application number	US-201514945624-A
Country	US
Kind code	A1
Filing date	Nov 19, 2015
Priority date	Nov 21, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A lens unit which is capable of efficiently combining a plurality of plastic lenses, which are small, easy to assemble, and inexpensive, and holding them with high accuracy without increasing the outer diameter of the lens unit. A first lens and a second lens are made of plastic, and the second lens is fitted and held on a rear side of the first lens in a direction of an optical axis. A gate for use in molding the second lens is disposed on a cut surface formed by cutting out a part of an outer periphery of the second lens, and a convex portion corresponding in shape to a remaining part of the gate after molding of the second lens is disposed in a space between an inner peripheral surface of a portion of the first lens in which the second lens is fitted and held and the cut surface.

First claim

What is claimed is:

1 . A lens unit comprising:
a first lens configured to be made of plastic; a second lens configured to be fitted onto and held on a rear side of said first lens in a direction of an optical axis and made of plastic; and a lens holder configured to be disposed on a rear side of said second lens and hold said second lens, wherein a gate for use in molding said second lens is disposed on a cut surface formed by cutting out a part of an outer periphery of said second lens, and a convex portion corresponding in shape to a remaining part of the gate after molding of said second lens is disposed in a space between an inner peripheral surface of a fitting holding portion of said first lens in which said second lens is fitted and held and the cut surface.

2 . The lens unit according to claim 1 , wherein, on an inner periphery of the fitting holding portion, rotation inhibiting projections that inhibit rotation of said second lens with respect to said first lens are provided at positions on both sides of the convex portion of said second lens in a circumferential direction.

3 . The lens unit according to claim 1 , wherein an urging member that urges said first lens as well as said second lens toward said lens holder is provided on a front side of said first lens, and the urging member is fixed to said lens holder.

4 . A lens unit comprising:
a first lens configured to be made of plastic; a second lens configured to be fitted and held on a rear side of said first lens in a direction of an optical axis and made of plastic; and a lens holder configured to be disposed on a rear side of said second lens and hold said second lens, wherein a gate for use in molding said second lens is disposed on an outer periphery of said second lens, and a convex portion corresponding in shape to a remaining part of the gate after molding of said second lens is inserted into a cutout portion formed in a peripheral wall of a fitting holding portion of said first lens on which said second lens is fitted and held.

5 . The lens unit according to claim 4 , wherein the convex portion is inserted into the cutout portion so as not to project outward in a radial direction from an outer periphery of said first lens.

6 . The lens unit according to claim 4 , wherein an urging member that urges said first lens as well as said second lens toward said lens holder is provided on a front side of said first lens, and the urging member is fixed to said lens holder.

7 . An optical device comprising:
a lens unit having a first lens made of plastic, a second lens fitted and held on a rear side of the first lens in a direction of an optical axis and made of plastic, and a lens holder disposed on a rear side of the second lens and holding the second lens, wherein a gate for use in molding the second lens is disposed on a cut surface formed by cutting out a part of an outer periphery of the second lens, and a convex portion corresponding in shape to a remaining part of the gate after molding of the second lens is disposed in a space between an inner peripheral surface of a fitting holding portion of the first lens in which the second lens is fitted and held and the cut surface.

8 . An optical device comprising:
a lens unit having a first lens made of plastic, a second lens fitted and held on a rear side of the first lens in a direction of an optical axis and made of plastic, and a lens holder disposed on a rear side of the second lens and holding the second lens, wherein a gate for use in molding the second lens is disposed on an outer periphery of the second lens, and a convex portion corresponding in shape to a remaining part of the gate after molding of the second lens is inserted into a cutout portion formed in a peripheral wall of a fitting holding portion of the first lens in which the second lens is fitted and held.

Assignees

• Canon Kk

Inventors

• Kudoh Tomoyuki

Classifications

• G02B7/021 Primary

  for more than one lens · CPC title

• G02B7/08

  adapted to co-operate with a remote control mechanism · CPC title

• G02B7/022 Primary

  lens and mount having complementary engagement means, e.g. screw/thread · CPC title

• G02B7/026

  using retaining rings or springs (G02B7/027 takes precedence) · CPC title

• G02B1/041

  Lenses · CPC title