WO2007086190A1

WO2007086190A1 - Lens holding structure

Info

Publication number: WO2007086190A1
Application number: PCT/JP2006/323562
Authority: WO
Inventors: Minoru Kuwana; Hiroyoshi Hosota
Original assignee: Konica Minolta Opto, Inc.
Priority date: 2006-01-25
Filing date: 2006-11-27
Publication date: 2007-08-02

Abstract

A lens holding structure wherein an angle of a lens having a lens plane non-rotationally-symmetric with respect to an optical axis is accurately fixed around the optical axis. In the lens holding structure, one abutting plane (4) of either a lens (1) or a holding frame (2) is provided with a truncated cone shaped protruding section (7), which protrudes in the direction of the optical axis (x) and has a side wall inclined in taper, and the other abutting plane (3) is provided with a recessed section (6) having a taper inclined in the same manner for accepting the protruding section (7).

Description

Specification

Lens holding structure

Technical field

[0001] The present invention relates to a lens holding structure.

Background art

A normal lens is configured with a lens surface that is rotationally symmetric with respect to the optical axis. However, as described in Patent Document 1, the focal point is different between the upper and lower sides of the lens and is symmetric with respect to the optical axis. There are also lenses with non-lens surfaces. Even if it has a non-rotationally symmetric lens surface, a lens whose projected shape in the optical axis direction is circular may be due to an assembly device using image processing that makes it difficult to accurately determine the top and bottom of the lens. The accuracy is limited to about ± 5 ° around the optical axis.

[0003] In order to satisfy this requirement, it is often necessary to finely adjust the rotational position of the lens while confirming the image formation. was there.

Patent Document 1: Japanese Patent Laid-Open No. 9-236851

Disclosure of the invention

Problems to be solved by the invention

In view of the above problems, the present invention provides a lens holding structure that can accurately determine the angle around the optical axis of a lens having a lens surface that is non-rotationally symmetric with respect to the optical axis. Is an issue.

Means for solving the problem

In order to solve the above problems, a lens holding structure according to the present invention holds the outer periphery of a lens having a non-rotationally symmetric lens surface with a holding frame, and the lens and the holding frame in the optical axis direction. A lens holding structure for positioning the lens by providing an abutting surface for abutting the lens and the holding frame! It is assumed that a convex portion protruding in the optical axis direction is provided on one of the contact surfaces, and a concave portion for receiving the convex portion is provided on the other contact surface. [0006] According to this configuration, the rotational position of the lens around the optical axis can be accurately adjusted by fitting the convex portion into the concave portion.

[0007] Further, in the lens holding structure of the present invention, at least the convex portion and the concave portion

V, one of the gaps is formed in a tapered shape with an inclined side wall surface!

[0008] According to this configuration, when the convex portion is inserted into the concave portion, the taper becomes a pressure angle to rotate the lens, and the rotational position of the lens is brought close to the reference position. The final lens rotational positioning accuracy can be made higher than the required accuracy.

[0009] Further, in the lens holding structure of the present invention, the convex portion and the concave portion may be formed in a truncated cone shape whose side wall surfaces have the same inclination angle.

[0010] According to this configuration, when the convex portion and the concave portion are fitted to each other, the inclination of the convex portion and the concave portion coincides, so that the lens can be rotated smoothly.

[0011] Further, in the lens holding structure of the present invention, when the tip of the convex portion is positioned at the opening of the concave portion, the convex portion is configured so that the lens can be rotated about ± 5 ° or more around the optical axis. The gap between the convex portion and the concave portion is made small so that the lens cannot be rotated about ± 2 ° or more around the optical axis in a state where the contact surfaces where the opening of the concave portion is larger than the tip of the concave portion are in contact with each other. May be.

[0012] According to this configuration, the lens can be positioned with an accuracy of ± 2 ° or less by fitting the convex portion and the concave portion using an assembly apparatus with a positioning accuracy of ± 5 °.

[0013] Further, in the lens holding structure of the present invention, the lens may be provided with a gate for injection molding on the opposite side of the convex portion or the concave portion with respect to the optical axis.

According to this configuration, in the injection molding of the lens, the disturbance of the flow of the resin material due to the provision of the convex portion or the concave portion does not appear within the effective range of the lens, so that the optical performance of the lens is improved. There is no loss.

The invention's effect

As described above, in the lens holding structure of the present invention, the lens and the holding frame are provided with the convex portion and the concave portion that are fitted to each other, so that the rotational position of the lens can be accurately adjusted. Brief Description of Drawings

FIG. 1 is a cross-sectional view of a lens holding structure according to a first embodiment of the present invention. 2 is a cross-sectional view showing an assembly process of the lens holding structure in FIG. 1.

FIG. 3 is a schematic diagram showing the relationship between the convex portion and the concave portion in FIG. 2 as viewed in the optical axis direction.

4 is a schematic diagram showing the relationship between the convex part and the concave part in FIG. 1 as viewed in the optical axis direction.

FIG. 5 is a configuration diagram of a mold for forming the lens of FIG.

FIG. 6 is a sectional view of a lens holding structure according to a second embodiment of the present invention.

Explanation of symbols

[0017] 1 lens

2 Holding frame

3 Contact surface

4 Contact surface

6, 6 'recess

7, 7 'Convex

11 cavity

12 Gate

13 Protrusion

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] Now, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a lens holding structure according to a first embodiment of the present invention. In this structure, the lens 1 made of resin is held by the holding frame 2. Lens 1 has different focal points in the upper half and lower half, and has a non-rotationally symmetric lens surface with respect to optical axis X. The shape of the outer circumference (projection shape in the direction of optical axis X) is circular. ing. The holding frame 2 has a cylindrical inner surface and holds the outer periphery of the lens 1. Furthermore, lens 1 and holding frame 2 have contact surfaces 3 and 4 that face each other in the optical axis X direction, and contact surface 3 of lens 1 is in contact with contact surface 4 of holding frame 2. It is fixed with adhesive 5 with lens 1 inserted until it contacts. In the lower part of the contact surface 3 of the lens 1, a recess 6 having a truncated conical shape in the direction of the optical axis X and having a side wall surface inclined in a taper shape is formed. Then, a frustoconical projection 7 having a taper-like side wall surface projecting in the direction of the optical axis X and having the same inclination angle as that of the recess 6 is formed, and the projection 7 is fitted in the recess 6. FIG. 2 shows a process of inserting the lens 1 into the holding frame 2. The lens 1 is held by a robot (not shown), and is inserted from the open end (right side in the figure) of the holding frame 2 with the top (rotation position) aligned. FIG. 2 shows a state in which the lens 1 is inserted until the tip of the convex portion 7 is positioned at the opening of the concave portion 6.

FIG. 3 shows the relationship between the concave portion 6 and the convex portion 7 as viewed from the optical axis X direction in the state of FIG.

The lens 1 is a force in which the position of the optical axis X is determined by the holding frame 2. The rotational position around the optical axis X may have an error of about ± 5 ° when the robot holds the range. On the other hand, since the tip of the convex portion 7 is smaller than the opening of the concave portion 6, there is a deviation of the rotational position up to ± 7.8 ° around the optical axis X as shown by the two-dot chain line in the figure. Even so, the tip of the convex portion 7 fits within the opening of the concave portion 6. For this reason, the robot can insert the lens 1 into the holding frame 2 so that the tip of the convex portion 7 enters the opening of the concave portion 6.

When the lens 1 is inserted into the holding frame 2, the inclined surface of the convex portion 7 comes into contact with the inclined surface of the concave portion 6. Further, when the lens 1 is inserted deeply, the convex portion 7 advances toward the center of the concave portion 6 along the inclined surface of the concave portion 6, thereby rotating the lens 1 around the optical axis X. Therefore, the robot that inserts the lens 1 into the holding frame 2 needs to have a structure that allows such rotation of the lens 1.

[0023] FIG. 4 shows the opening and convexity of the recess 6 as seen from the optical axis X direction when the contact surface 3 of the lens 1 is in contact with the contact surface 4 of the holding frame 2 as shown in FIG. The relationship with the root part of Part 7 is shown. As shown in the figure, in this state, the gap between the concave portion 6 and the convex portion 7 is smaller than the state of FIG. 3, and the lens 1 is ± 1.7 around the optical axis X. Can only rotate.

That is, the lens holding structure of the present embodiment uses an assembling apparatus capable of rotational positioning with a maximum accuracy of ± 7.8 ° around the optical axis X, and ± 1.7 around the optical axis X. ° It can be positioned with high accuracy below. Therefore, the assembly accuracy of ± 2 ° or less required for the lens unit can be achieved without any adjustment work with positioning accuracy of ± 5 ° that can be realized by an automatic assembly device.

Next, FIG. 5 shows a configuration of a mold for injection molding the lens 1 of the present embodiment.

The lens 1 includes a fixed mold 8 that forms a lens surface opposite to the contact surface 3, a sleeve 9 that forms an outer peripheral surface, and a lens surface on the contact surface 3 and the contact surface 3 side. Consisting of 10 cores to form In the cavity 11, lens resin dissolved from the gate 12 opened on the outer peripheral surface of the cavity 11 is injected and molded. The core 10 has a recess on the opposite side of the gate 12 with respect to the optical axis X.

Protrusions 13 for forming 6 are provided.

The grease injected from the gate 12 spreads into the cavity 11, but the flow is disturbed behind the protrusion 13 when viewed from the gate 12. Such disturbance of the flow of the grease during the injection molding may cause variations in optical characteristics. The optical performance of lens 1 is not impaired.

[0028] Further, FIG. 6 shows a lens holding structure according to a second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, a truncated cone-shaped convex portion 7 ′ that protrudes in the optical axis X direction and whose side wall surface forms a taper is formed on the contact surface 3 of the lens 1. The contact surface 4 is formed with a recess 6 ′ that fits with the protrusion 7 ′.

[0030] Also in this embodiment, the convex portion 7 'advances toward the center of the concave portion 6', so that the lens 1 can be rotationally positioned with high accuracy.

In the present invention, the convex portion and the concave portion do not necessarily have the same inclined taper. For example, only one of them may have a taper and the other may be a straight body.

[0032] Further, the projected shape of the convex portion and the concave portion in the optical axis direction is not necessarily circular. For example, it may be formed in a pyramid shape having a square projected shape.

Claims

The scope of the claims

[1] The outer periphery of a lens having a non-rotationally symmetric lens surface is held by a holding frame, and the lens and the holding frame are each provided with an abutting surface that abuts in the optical axis direction to position the lens. A lens holding structure,

A convex portion protruding in the optical axis direction is provided on one of the abutting surfaces of the lens and the holding frame, and a concave portion for receiving the convex portion is provided on the other abutting surface. A lens holding structure.

[2] The lens holding structure according to claim 1, wherein at least one of the convex portion and the concave portion is formed in a tapered shape with an inclined side wall surface.

[3] The lens holding structure according to claim 1, wherein the convex part and the concave part are formed in a truncated cone shape having side wall surfaces having the same inclination angle.

[4] When the tip of the convex portion is positioned at the opening of the concave portion, the lens is moved around the optical axis.

The opening of the concave portion is larger than the tip of the convex portion so that it can be rotated by 5 ° or more.

The gap between the convex portion and the concave portion is reduced so that the lens cannot be rotated about ± 2 ° or more around the optical axis in a state where the contact surfaces are in contact with each other. The lens holding structure according to item 3 or 3.

5. The lens according to any one of claims 1 to 4, wherein a gate for injection molding is provided on the opposite side of the convex portion or the concave portion with respect to the optical axis. 2. The lens holding structure according to item 1.