JPH04257808A - Lens holding member - Google Patents

Abstract

PURPOSE:To surely make the mutual optical axes of plural lenses coincident even if a clearance between the outer diameter of a lens and the inner diameter of a lens-barrel exists, to stabilize characteristics, further, to eliminate the need of a lens vibration proofing mechanism, to relax the working precision of the parts of the lens, the lens-barrel, etc., and to reduce production cost and assembling/adjusting cost by providing a positioning part on the inner peripheral part of the lens-barrel being a barrel holding member, and abutting the lens upon the positioning part with the shrinkage force of an adhesive, in a lens holding member. CONSTITUTION:The barrel lens holding member 11 holding plural lenses 12 on the inner peripheral part is achieved in such a manner that the positioning parts 15 and 16 of the lenses 12 are provided on the inner peripheral part of the barrel holding member 11 holding the lenses 12, the lenses 12 are butted against the positioning parts 15 and 16 by the shrinkage force of the adhesive 23, and the mutual optical axes of plural lenses 12 are coincident.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a lens holding member, for example, a lens barrel that converges a beam of an optical lens.
The present invention relates to a lens holding member that is a lens barrel positioned with high precision in an optical section of an image forming apparatus.

0002

2. Description of the Related Art As a conventional lens holding member, there is, for example, one shown in FIG. 3 described in Japanese Utility Model Application No. 140013/1980. The lens holding member 1 shown in FIG. 3 is a lens barrel that converges an optical beam, and when the lenses 2 are installed and fixed, three lenses 2 are installed in the lens barrel 3, which is a cylindrical holding member. After that, the optical axis of each lens 2 is adjusted, and then an adhesive is filled through the hole 4 of the lens barrel 3, which also serves as a vibration isolation mechanism, and fixed.

The most important function of the lens holding member 1 is to align two or more lenses 2, that is, to align their optical axes.

0004

However, in such a conventional lens holding member, the outer circumference 2a of the lens 2 and the inner circumference 3a of the lens barrel 3 are separated in consideration of ease of assembling the lens 2.
A clearance 6 is provided between the two. and,
In order to control the amount of clearance 6, strict dimensional tolerances are required between the outer diameter of the lens 2 and the inner diameter of the lens barrel 3. For this reason, since these parts are processed and manufactured with high precision in accordance with dimensional tolerances, there is a problem in that the cost of each of these parts increases.

On the other hand, if there are large variations in the dimensions of each of these parts and the amount of clearance 6 described above cannot be controlled, the entire lens unit in which the lens is assembled can be rotated and adjusted to assemble it into the equipment and create the desired lens. Obtained the characteristics of the unit. For this reason, there is a problem in that after such high-precision parts are assembled, extra effort is required for assembly and adjustment, which increases the cost of adjustment work.

[0006]

OBJECTS OF THE INVENTION The present invention has been made against the background of the above-mentioned problems of the prior art.A positioning portion is provided on the inner circumference of the lens barrel, which is a cylindrical holding member, and the shrinkage force of the adhesive is reduced. By pressing the lens against the positioning area,
Even if there is a clearance between the outer diameter of the lens and the inner diameter of the lens barrel, it is possible to reliably align the mutual optical axes of multiple lenses and stabilize the characteristics.Furthermore, there is no need for a lens anti-vibration mechanism, and the lens, It is an object of the present invention to provide a lens holding member that can reduce the machining accuracy of parts such as a lens barrel and reduce manufacturing costs and assembly and adjustment costs.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides, in claim 1, a cylindrical lens holding member that holds a plurality of lenses on its inner periphery; Claim 2 is characterized in that a positioning part for the lens is provided in the part, and the lens is abutted against the positioning part by the contractile force of the adhesive to align mutual optical axes of the plurality of lenses. In the lens holding member, the holding member has an injection hole provided on a peripheral wall into which the adhesive can be injected, and a 1/4-circle circle from the injection hole on both sides of the injection hole on the inner circumference of the holding member. In the lens holding member according to claim 1 or 2, the positioning portion is provided at at least two positions at a closer distance, and in claim 3, in the lens holding member according to claim 1 or 2, The present invention is characterized in that a guide is provided on the opposite side of the injection hole with respect to the central axis of the holding member, protruding inward and holding the lens.

[0008]

[Operation] In the present invention, a positioning part is provided on the inner circumference of the cylindrical holding member, and the outer circumference of the lens is abutted against and fixed to the positioning part by the contractile force of the adhesive.
The lenses are fixed in a state in which the outer circumferences of the lenses are in contact with the positioning portions, that is, the optical axes of the plurality of lenses are aligned with each other. This eliminates the need for specific adjustment work to align the optical axes of the lenses with each other. Further, there is no need to control the clearance between the inner periphery of the holding member and the outer periphery of the lens, and there is no need to tighten the dimensional tolerances of each component.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. 1 and 2 are diagrams showing an embodiment of a lens holding member according to claims 1 to 3 of the present invention. First, the configuration will be explained. In FIGS. 1(a) and 1(b), 11 is a lens holding member, and the lens holding member 11 is made of a resin member, and is a cylindrical holding member that holds two lenses 12A and 12B (referred to as 12 when representing). It has a lens barrel 13 which is a member. The inner peripheral part 13a of the lens barrel 13 has three first to third ribs that protrude toward the central axis P side of the lens barrel 13 along the entire length of the barrel, at positions where the inner peripheral length of the lens barrel 13 is divided into three equal parts. 15, 16,
17 are provided. That is, the first to third ribs 15,
16 and 17 are arranged at an angle of 120 degrees with respect to the central axis P. The inner surfaces 15a and 16a of the first rib 15 and the second rib 16 are positioning parts,
Align the optical axes of lens 12A and lens 12B to align lens barrel 1.
This is the positioning reference held at 3. The third rib 17 is located on the opposite side of the injection hole 20, which will be described later, with respect to the central axis P of the lens barrel, and serves as a guide when holding and adjusting the lens 12 within the lens barrel 13.

An injection hole 20 communicating from the outside to the inside of the lens barrel 13 is provided at the center of the first rib 15 and the second rib 16 on the peripheral wall of the lens barrel 13 . As shown in FIG. 2, the injection hole 20 has a rectangular cross section in a direction parallel to the central axis P, and the size L20A of the circumferential outer opening 20a is larger than the size L20B of the circumferential inner opening 20b. , and has a step 20c. This step 20c is provided to prevent the adhesive 23 after hardening, which will be described later, from being drawn inward. The peripheral wall of the lens barrel 13 in the vicinity of the injection hole 20 has an increased wall thickness in order to strengthen the peripheral wall, and the inner surface 18 has a planar shape, a so-called D-cut shape. The injection hole 20 is provided at a central angle of 60 degrees from the first rib 15 and the second rib 16 with respect to the central axis P;
The rib 16 is connected to the injection hole 20 on the circumference of the inner peripheral surface 13a of the lens barrel 13.
This means that they are provided at a distance closer than 1/4 of the circumference from the injection hole 20 on both sides. In addition, the injection hole 20 is located at the first rib 15.
It is preferable that the lens 12 be located at the center in the circumferential direction with respect to the second rib 16. This is because when the lens 12, which will be described later, is positioned against the first rib 15 and the second rib 16, the pressing force of the lens 12 is applied to the first rib 15 and the second rib 16. 15 and the second rib 16, and the lens 12 is stabilized within the lens barrel.

21 is an intermediate ring;
is interposed between the lenses 12A and 12B, and fixes the distance between the two lenses 12 in the direction of the central axis P. 23 is an adhesive, and the adhesive 23 is injected from the outside of the lens barrel 13 into the injection hole 20 and penetrates into the gap 19 between the outer circumferential surface 12a of the lens 12 and the inner surface 18 of the lens barrel 13, and the adhesive 23 is injected into the injection hole 20 from the outside of the lens barrel 13, and penetrates into the gap 19 between the outer peripheral surface 12a of the lens 12 and the inner surface 18 of the lens barrel 13.
2a, and when shrinking and hardening, it shrinks with a large shrinkage force,
The lens 12 is abutted against the inner surface 15a of the first rib 15 and the inner surface 16a of the second rib 16, so that the mutual optical axes of the two lenses 12 are aligned. The adhesive 23 is a synthetic resin that has a large shrinkage rate when cured, and is, for example, an acrylic adhesive. In addition, the adhesive 23 is preferably a nitrile rubber adhesive, and any resin having a high curing shrinkage rate such as a UV curable adhesive or an epoxy adhesive may be used.

When holding and fixing the lens 12 in the lens barrel 13, first insert the lens 1 into the lens barrel 13 with the intermediate ring 21 in between.
2A and lens 12B are inserted, and the outer peripheral surface 1 of lens 12 is
2a is supported by three first to third ribs 15, 16, 17,
The approximate positions of the lenses 12A and 12B within the lens barrel 13 are determined. Next, the injection hole 20 is opened from the outside of the lens barrel 13.
As shown in FIG. 2, an acrylic adhesive 23 having a high curing shrinkage rate is injected through the tube. The adhesive 23 is injected into the injection hole 20
filling the inside, filling the step 20c, and filling the inner surface 18 of the lens barrel 13.
and the outer peripheral surface 12a of the lens 12. The adhesive 23 that has penetrated into the gap 19 spreads slightly along the outer peripheral surface 12a of the lens 12, and is strongly adhered to the outer peripheral surface 12a. Next, the adhesive 23 begins to harden and shrink.
As the adhesive 23 shrinks, the lens 12 shrinks to the outer peripheral surface 12a.
is drawn into the bonded injection hole 20 side, and as a result, the outer circumferential surface 12a of the lens 12 evenly presses the inner surface 15a of the first rib 15 and the inner surface 16a of the second rib 16, and the lens 12 is positioned. 12 comes into contact with the inner surfaces 15a and 16a and is fixed. At this time, the optical axes of the lenses 12A and 12B are aligned.

Next, the operation will be explained. In the present invention, the first rib 1, which is a positioning portion, is provided on the inner peripheral portion 13a of the lens barrel 13.
Since the outer circumferential surface 12a of the lens 12 is supported and positioned by the inner circumferential surface 15a of the lens 12 and the inner circumferential surface 16a of the second rib 16, the inner circumferential surface 12a of the lens 12 and the inner circumferential portion 13a of the lens barrel 13 are There is no need to tighten the precision of the clearance, the work of the lens barrel 13 and the lens 12 can be done easily and quickly, and furthermore, there is no need to manage the clearance, so manufacturing costs can be reduced.

[0014] Further, unlike in the prior art, extra work time for assembly and adjustment due to large variations in the dimensions of parts such as the lens 12 and lens barrel 13 is not required. Furthermore, in order to align the optical axes of the lenses 12A and 12B, an adhesive 23 having a large shrinkage rate upon curing is used from the injection hole 20, and the contraction force of the adhesive 23 causes the outer circumferential surface 12a of the lens 12 to be aligned with the lens barrel 12. The positioning is performed by abutting against the inner surface 15a of the first rib 15 and the inner surface 16a of the second rib 16 provided on the inner circumferential portion 13a of the lens 12B. Assembly and adjustment work is simplified, lens assembly work can be done quickly, and assembly costs can be reduced.

Furthermore, since the injection hole 20 is provided at the center between the first rib 15 and the second rib 16 on the circumference of the lens barrel 13,
Due to the contraction force of the adhesive 23, the lens 12 is attached to the first rib 15.
The pressing force for pressing the second rib 16 becomes uniform, and the lens 12 is stably fixed within the lens barrel 13. In addition, the wall thickness near the injection hole 20 of the lens barrel 13 is increased and the strength is increased, and the injection hole 20 is formed closer to the outer opening 20 of the injection hole 20.
a is larger than the internal opening 20b, and a step 20c is provided, so that the adhesive 23 is injected into the injection hole 20 and adhered to the outer circumferential surface 12a of the lens 12, and then when it hardens and shrinks, the adhesive 23 is attached to the lens barrel. In addition to preventing the adhesive 23 from being drawn into the inside of the lens 13, the hardened adhesive 23 and the lens barrel 13 are made integral, and the lens barrel 13 is not deformed, and the optical axes of the lenses 12A and 12B are aligned. The characteristics of the lens become stable under this condition. Moreover, since the lens barrel 13 is a resin member, mold processing is also easy by forming it into this shape.

In the above-mentioned embodiment, the case was described in which two lenses, the lens 12A and the lens 12B, were housed in the lens barrel 13, but the present invention is not limited to this embodiment; Of course, there may be three or more. Furthermore, in the above embodiment, the lens barrel 13
Two first ribs 15 and a second rib 1 are provided on the inner circumference 13a of the
Although the case where the number is 6 has been described, the number may be 2 or more. Of course, the number may be further increased depending on the shape of the lens 12. In addition, the inner surface 15 of the positioning part
a and the inner surface 16a may not be surfaces, for example, may be edges or circular arcs.

[0017]

[Effects of the Invention] As explained above, according to the present invention,
By providing a positioning part on the inner circumference of the cylindrical holding member and abutting the lens against the positioning part using the contractile force of the adhesive, even if there is a clearance between the outer diameter of the lens and the inner diameter of the lens barrel, multiple The mutual optical axes of the lenses can be reliably aligned, and the characteristics can be stabilized.Furthermore, a lens anti-vibration mechanism is no longer required, reducing the machining precision of parts such as lenses and lens barrels, reducing manufacturing costs and assembly adjustment costs. can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of a lens holding member according to claims 1 to 3 of the present invention, in which (a) is a front view of a lens barrel, and (b) is a longitudinal sectional view of the lens barrel housing a lens. It is.

FIG. 2 is an enlarged cross-sectional view of a main part of the lens shown in FIG. 1, which is fixed with adhesive.

FIG. 3 is a partial longitudinal sectional view of a conventional lens holding member.

[Explanation of symbols]

11 Lens holding members 12, 12A, 12B Lens 13 Lens barrel (holding member) 15 First rib (positioning part) 16 Second rib (positioning part) 15a, 16a Inner surface (
Positioning part) 17 Third rib (guide) 20 Injection hole 23 Adhesive P Center axis

Claims (3)

[Claims] 1. A cylindrical lens holding member that holds a plurality of lenses on its inner periphery, wherein a lens positioning portion is provided on the inner periphery of the cylindrical holding member that holds the lenses, and a positioning portion is provided on the inner periphery of the cylindrical holding member that holds a plurality of lenses. A lens holding member characterized in that the lens is brought into contact with the positioning portion by force to align mutual optical axes of the plurality of lenses. 2. The holding member has an injection hole provided on a peripheral wall and into which the adhesive can be injected, and an injection hole on both sides of the injection hole on the inner circumference of the holding member from 1/4 turn from the injection hole. the positioning portions provided at at least two locations close to each other;
The lens holding member according to claim 1, characterized in that it has: 3. A guide is provided on the inner periphery of the holding member on a side opposite to the injection hole with respect to the central axis of the holding member, the guide projecting inward and holding the lens. The lens holding member according to 1 or 2.