JPH0256642B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a lens holding device, and more particularly to a lens holding device that fixes and holds a lens and a lens frame to each other via an adhesive.

BACKGROUND ART Conventionally, a lens holding device for fixing and holding a lens and a lens frame to each other via an adhesive is configured as shown in FIG. 4, for example.

That is, the lens 101 is housed in the lens accommodating part 103 of the lens frame 102, and the lens is connected to the lens accommodating part 103 and protrudes inward in the radial direction, and the lens is attached to the locking ridge 104 provided in the lens frame 102. 101 to restrict its movement in the optical axis direction, and the outer circumferential surface of the lens 101 and the lens housing portion 1
An adhesive layer 105 is formed between the inner peripheral surface of the lens 101 and the lens frame 102 to fix and hold the lens 101 and the lens frame 102 to each other.

Therefore, the formation of the adhesive layer 105 is carried out after the lens 101 is housed in the lens housing part 103 and then between the outer peripheral surface of the lens 101 and the inner peripheral surface of the lens housing part 103. The lens 10 can be filled with adhesive using a sharply shaped rod-shaped filling tool and cured, or the lens 10 can be
1 is rotated around the optical axis l, an adhesive 106 is applied to the outer circumferential surface of the lens using a needle applicator 7, and then the lens 101 is attached to the locking protrusion 10.
This is done by making the adhesive 106 harden by placing it in contact with the lens accommodating portion 103 and hardening the adhesive 106.

However, the conventional lens holding device described above has various problems as described below.

(1) As the adhesive 106 hardens and shrinks, the lens 1
01 is pulled outward in the radial direction, wrinkles (as, cracks) occur on the lens surface, and the lens 10
The performance after assembly with the lens frame 102 of 1 is the same as that of lens 10.
The performance is lower than that of 1 alone.

(2) If the lens 101 is centered with respect to the lens frame 102 before the adhesive 106 hardens, the lens 1
The lens 101 moves in the radial direction due to the difference in the amount of shrinkage of the adhesive 106 due to the variation in the distance between the outer circumferential surface of the lens 101 and the inner circumferential surface of the lens housing part 103, causing the lens 101 to move in the radial direction. This causes misalignment.

(3) Outer peripheral surface of lens 101 and lens housing portion 103
Since the adhesive layer 105 between the inner circumferential surface of
Internal stress is generated in the lens 101, causing a distortion (distortion) on the surface of the lens 101.

OBJECTS OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a lens holding device that does not cause performance deterioration due to assembly and maintains high performance even when the temperature changes in the usage environment.

Summary of the Invention The present invention forms a space between the fitting protrusion of the lens and the large-diameter circumferential wall of the accommodation groove of the lens frame, and an elastic adhesive layer is interposed between the small-diameter circumference of the accommodation groove and the elastic adhesive layer. It is a ring fit and allows the lens to be displaced due to temperature without distortion.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a half-cut longitudinal sectional view showing a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a lens made of plastic, and the lens 1 includes a lens body 2, a flange portion 3 integrally formed on the outer periphery of the lens body 2 and extending outward in the radial direction (in the left-right direction in the figure). It is constituted by a fitting protrusion 4 which is integrally formed and projects from the periphery of the flange portion 3 in one direction in the axial direction (vertical direction in the figure).

The lens 1 is assembled into a short cylindrical lens frame 5 made of metal or the like having a smaller coefficient of thermal expansion than the lens 1 via its fitting protrusion 4 .

That is, on one (upper side in the figure) end surface of the lens frame 5, a housing groove 6 is provided in a ring shape centered on the axis of the lens frame 5. The accommodation groove 6 is for accommodating the fitting protrusion 4 of the lens 1, etc., as will be described later, and the diameter of its small diameter peripheral wall is appropriately smaller than the diameter of the inner circumferential wall of the fitting protrusion 4 of the lens 1. The diameter of the circumferential wall is set to be appropriately larger than the diameter of the outer circumferential wall of the fitting protrusion 4 of the lens 1, and the axial length of the small diameter circumferential wall is set in the axial direction of the inner circumferential wall of the fitting protrusion 4 of the lens 1. It is set shorter than the length.

The fitting protrusion 4 of the lens 1 is formed in the accommodation groove 6 of the lens frame 5 with a certain space 7 formed between its outer circumferential wall and the large-diameter circumferential wall of the accommodation groove 6. The end face of the mating protrusion 4 is brought into contact with the bottom face of the housing groove 6 and is housed concentrically, and an adhesive layer 8 having elasticity and having a rectangular cross section is used to fix and hold the lens 1 and the lens frame 5 to each other. is interposed between the small diameter circumferential wall of the accommodation groove 6 and the inner circumferential wall of the fitting protrusion 4.

In addition, in order to form a certain space 7 between the large-diameter peripheral wall of the housing groove 6 and the outer periphery of the lens 1 in order to position the fitting protrusion 4 concentrically in the housing groove 6, as shown in FIG. A cylindrical positioning jig 9 indicated by a two-dot chain line in
is inserted between the two, and the adhesive layer 8
It is removed after the formation of the

Therefore, according to the above embodiment, it is possible to accurately and easily position the lens 1 and the lens frame 5 in the radial and axial directions during assembly, and the lens 1 can be easily positioned due to temperature changes after assembly. Even if it is displaced relative to the lens frame 5 in the radial direction, the adhesive layer 8 is elastically deformed and the gap between the holes 7 is only widened or narrowed, so that distortion such as asperity does not occur in the lens 1.

In addition, in the above-mentioned embodiment, a case was described in which the end face of the fitting protrusion 4 and the bottom face of the accommodation groove 6 were brought into contact in order to position the lens 1 and the lens frame 5 in the axial direction, but the present invention is not limited to this. Flange part 2 of lens 1
The inner end surface of the lens frame 5 may be brought into contact with the end surface of the lens frame 5.

FIG. 2 is a half-cut vertical cross-sectional view showing a second embodiment of the present invention. In this embodiment, the inner circumferential wall of the fitting protrusion of the lens 1 and the small-diameter circumferential wall of the accommodation groove 6 of the lens frame 5 are fitted. The difference from the first embodiment is that the lens 1 and the lens frame 5 are positioned in the radial direction, and the other points are almost the same as the first embodiment. The same reference numerals are used to omit the explanation.

That is, in this embodiment, the diameter of the small-diameter peripheral wall of the housing groove 6 of the lens frame 5 is provided approximately equal to the diameter of the inner peripheral wall of the fitting protrusion 4 of the lens 1, and
The diameter of the large-diameter peripheral wall of the accommodation groove 6 is appropriately larger than the diameter of the outer peripheral wall of the fitting protrusion 4, and the lens frame 5
An adhesive layer accommodating stepped portion 10 is provided by cutting out a rectangular end face of the accommodating groove 5 on the side of the small diameter peripheral wall.

Then, on the small diameter peripheral wall of the accommodation groove 6 of the lens frame 5,
The inner peripheral wall of the fitting protrusion 4 of the lens 1 forms a lens displacement absorbing space 11 between the large diameter peripheral wall of the housing groove 6 and the outer periphery of the lens 1, and the end surface of the housing groove 6 on the small diameter peripheral wall side. and the flange portion 3 of the lens 1 are brought into contact and fitted together, and an elastic adhesive layer 8 is attached to the adhesive storage stepped portion 10 to securely hold the lens 1 and the lens frame 5 to each other. It is interposed between the surrounding lens 1 and the surrounding lens 1.

Therefore, according to the second embodiment, not only the axial positioning of the lens 1 and the lens frame 5 at the time of assembly, but also the radial positioning can be performed accurately and easily without using a jig. , even if the lens 1 is displaced radially outward relative to the lens frame 5 due to temperature changes after assembly, the adhesive layer 8
is elastically deformed and the distance between the lens displacement absorbing spaces 11 is only widened and narrowed, so that distortion such as asperity does not occur in the lens 1.

FIG. 3 is a half-cut longitudinal sectional view showing a third embodiment of the present invention, and this embodiment is different from the second embodiment of the lens 1.
The lens 1 and the lens frame 5 are positioned in the axial direction by bringing the flange portion 2 of the lens 1 into contact with the end surface of the small-diameter circumferential wall of the accommodation groove 6 in the lens frame 5. The end surface of the lens 1 and the lens frame are brought into contact with a plate-shaped friction damping member 12 such as a sheet of tetrafluoroethylene, nylon, or high-density polyethylene adhered to the bottom of the housing groove 6 of the lens frame 5. The second embodiment differs from the second embodiment in that the positioning in the axial direction of 5 is performed. Since other points are substantially the same as those in the second embodiment, the same members are given the same reference numerals and their explanations will be omitted.

Note that instead of using the friction damping material, a substance having a low friction coefficient such as tetrafluoroethylene or molybdenum dioxide can be directly applied to the fitting rim 4 of the lens and the lens frame 5.
A similar effect can be obtained by applying a coating to the contact area.

Therefore, according to the third embodiment, in addition to the effects of the second embodiment, there is an effect that the relative outward displacement of the lens 1 with respect to the lens frame 5 in the radial direction becomes smooth.

In each of the above-mentioned embodiments, the axial length of the small-diameter circumferential wall of the housing groove 6 of the lens frame 5 is made shorter than the axial length of the large-diameter circumferential wall, but this is not limited to this. The lengths may be equal or the lengths may be reversed.

Furthermore, in each of the embodiments, the case where the lens frame 5 is a single unit has been described, but it can also be applied to a case where the lens frame is a projecting edge integrally formed inside the lens barrel and protruding radially inward. Of course.

Effects of the Invention As described above, according to the first invention, it is possible to accurately and easily position the lens and the lens frame in the axial and radial directions when they are assembled, and also to prevent temperature changes after assembly. Displacement of the lens in the radial direction relative to the lens frame can be absorbed by the elastic deformation of the adhesive layer and the void without causing distortion in the lens.

Further, according to the second invention, when assembling the lens and the lens frame, the axial positioning of both can be performed.
The radial positioning can be performed accurately and easily without using any jigs, and the radial outward displacement of the lens relative to the lens frame due to temperature changes after assembly can be prevented by the air. This has the effect of being able to absorb it without causing distortion in the lens.

[Brief explanation of the drawing]

1, 2, and 3 are half-cut vertical sectional views showing a first embodiment, a second embodiment, and a third embodiment of the present invention, respectively, and FIGS. 4 and 5 are longitudinal sectional views of the prior art, respectively. They are a top view and an explanatory view. DESCRIPTION OF SYMBOLS 1... Lens, 2... Lens main body, 3... Flange part, 4... Fitting protrusion, 5... Lens frame, 6... Accommodation groove, 7
...Empty, 8...Adhesive layer, 9...Positioning jig, 10
...Adhesive layer housing stepped portion, 11...Lens displacement absorbing space, 12...Friction damping member.

Claims (1)

[Scope of Claims] 1. A flange portion extending in the radial direction is provided on the outer periphery of the lens body of the lens, and a fitting protrusion that protrudes in the axial direction is provided on the periphery of the flange portion, and the A ring-shaped accommodating groove for accommodating the fitting protrusion of the lens is provided, and a predetermined space is formed between the large-diameter peripheral wall of the accommodating groove and the outer periphery of the lens. The lens holder is characterized in that the small-diameter circumferential wall of the accommodation groove of the lens frame and the inner circumferential wall of the fitting protrusion of the lens are joined via an elastic adhesive layer. Device. 2. The lens holding device according to claim 1, wherein the lens is made of plastic. 3. The lens holding device according to claim 1 or 2, wherein the end surface of the fitting protrusion of the lens is in contact with the bottom surface of the accommodating groove of the lens frame. 4. The lens holding device according to claim 1 or 2, wherein the lens has a flange portion thereof in contact with an inner circumferential end surface of a lens frame. 5 A flange portion extending in the radial direction is provided on the outer periphery of the lens body of the lens, and a fitting protrusion protruding in the axial direction is provided on the peripheral edge of the flange portion, and the fitting protrusion of the lens is provided on the end surface of the lens frame. A ring-shaped accommodation groove for accommodating the lens is provided, and an adhesive layer accommodation step is provided by cutting out the end face of the accommodation groove of the lens frame on the side of the small diameter circumferential wall, so that the lens fits into the small diameter circumference of the accommodation groove of the lens frame. A lens displacement absorbing cavity is formed between the large-diameter circumferential wall of the housing concave groove and the outer periphery of the lens to form a lens displacement absorbing cavity and fit together, and the adhesive layer housing stepped portion of the lens frame and the lens A lens holding device characterized in that an elastic adhesive layer is interposed between the fitting protrusion and the inner circumferential wall. 6. The lens holding device according to claim 5, wherein the lens is made of plastic. 7. The lens holding device according to claim 5 or 6, wherein the lens has a flange portion thereof in contact with an inner peripheral end surface of a lens frame. 8. According to claim 5 or 6, the lens is characterized in that the end surface of the fitting protrusion is in contact with a friction damping member attached to the bottom surface of the housing groove of the lens frame. lens holding device.