JPH0469885B2 - - 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 to a lens frame via an adhesive is configured as shown in FIG. 1, for example.

That is, the lens 1 is inserted into the lens housing section 3 of the lens frame 2.
At the same time, the lens 1 is moved in the direction of the optical axis l by contacting a locking ridge 4 provided in the lens frame 2 that is connected to the lens housing portion 3 and protruding radially inward. The lens 1 is fixed to the lens frame 2 by forming an adhesive layer 5 between the outer circumferential surface of the lens 1 and the inner circumferential surface of the lens accommodating portion 3 .

Therefore, the adhesive layer 5 is formed by dropping the lens 1 into the lens accommodating part 3 and then forming a syringe and a needle or a sharp tip between the outer peripheral surface of the lens 1 and the lens accommodating part 3. Alternatively, as shown in FIG. 2, the adhesive 6 may be applied to the outer peripheral surface of the lens 1 with a needle applicator 7 while rotating the lens 1 about the optical axis l. The adhesive 6 is applied in advance by using the adhesive, and then the lens 1 is brought into contact with the locking protrusion 4 and accommodated in the lens accommodating portion 3, and the adhesive 6 is cured.

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

(1) As the adhesive 6 hardens and shrinks, the lens 1 is pulled outward in the radial direction, causing wrinkles (asperities and cracks) on the lens surface, which may affect the performance of the lens 1 after assembly. The performance is lower than that of a single unit.

(2) Lens 1 to lens frame 2 before adhesive 6 hardens.
When performing centering, the lens 1 may shift in the radial direction due to differences in the amount of shrinkage of the adhesive 6 due to variations in the distance between the outer circumferential surface of the lens 1 and the inner circumferential surface of the lens housing portion 3. , causing misalignment between the lens 1 and the lens frame 2.

(3) Since the adhesive layer 5 between the outer peripheral surface of the lens 1 and the inner peripheral surface of the lens housing part 3 has poor elasticity, internal stress is generated in the lens 1 due to the difference in thermal expansion coefficient between the lens 1 and the lens frame 2. This causes the surface of the lens 1 to become wrinkled.

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 usage environment changes.

SUMMARY OF THE INVENTION The present invention provides a method for fitting a lens into a housing groove provided on an end face of a lens frame through its fitting protrusion, and also connecting the outer periphery of the lens and the large-diameter circumferential surface of the housing groove. An elastic adhesive layer is interposed to provide a lens deformation absorbing function.

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

FIG. 3 is a longitudinal sectional view showing the first embodiment of the present invention.

In the figure, reference numeral 11 denotes a lens made of plastic, and the lens 11 includes a lens body 12, a flange portion 13 integrally formed on the outer periphery of the lens body 12 and extending outward in the radial direction (left-right direction in the figure). It is constituted by a fitting protrusion 14 that is integrally formed on the peripheral edge of the flange portion 13 and protrudes in one direction (downward in the figure) in the axial direction (vertical direction in the figure).

The lens 11 is attached to a short cylindrical lens frame 15 made of metal or the like having a smaller coefficient of thermal expansion than the lens 11 via its fitting protrusion 14 .

That is, one side of the lens frame 15 (upper side in the figure)
A housing groove 16 is provided in a ring shape centered on the axis of the lens frame 15 on the end face of the lens frame 15 . Accommodation groove 16
is for housing the fitting protrusion 14 of the lens 11, etc., as described later, and the diameter of the small diameter peripheral wall is set as the lens 1.
approximately equal to the diameter of the inner circumferential wall of the fitting protrusion 14 of No. 1;
and the diameter of the large diameter peripheral wall is set to the fitting protrusion 14 of the lens 11.
The diameter of the small-diameter peripheral wall is appropriately larger than the diameter of the outer peripheral wall of the lens 11, and the axial length of the small-diameter peripheral wall is shorter than the axial length of the inner peripheral wall of the fitting protrusion 14 of the lens 11.

The fitting protrusion 14 of the lens 11 is inserted into the housing groove 16 of the lens frame 15 between its inner peripheral wall and the housing groove 16.
The lens 11 and the lens frame 15 are fitted together with the small diameter circumferential wall of the lens frame 16, and the end face of the fitting protrusion 14 is brought into contact with the bottom face of the accommodation groove 16, and the lens 11 and the lens frame 15 are fixedly held together. An elastic adhesive layer 17 having a rectangular cross section is attached to the outer periphery of the lens 11 and the housing groove 1.
A lens deformation absorbing space 18 is provided between the large-diameter peripheral surface of 6 and
is formed and interposed on the outer surface side (upper surface side in the figure).

Therefore, according to the above embodiment, the small-diameter circumferential wall of the accommodation groove and the inner circumferential wall of the fitting protrusion are fitted together, and the end face of the fitting protrusion is brought into contact with the bottom face of the accommodation groove. The positioning of the lens 11 and the lens frame 15 in the radial direction and axial direction when assembling the lens 11 and the lens frame 15 can be easily and accurately performed without using any jigs or the like.

In addition, since an elastic adhesive layer 17 is interposed between the outer periphery of the lens 11 and the large-diameter peripheral wall of the housing groove 16 to form a lens deformation absorbing space, the radial direction of the lens 11 due to temperature changes is Can absorb expansion and contraction.

FIG. 4 is a half-cut longitudinal sectional view showing a second embodiment of the present invention, and this embodiment is similar to the adhesive layer 1 of the first embodiment.
7 has a rectangular shape with a lens deformation absorbing space 18 formed on the outer surface side, whereas the lens deformation absorbing space 20 is formed on the large diameter circumferential wall side of the housing groove 16 by using an elastic adhesive layer 19. Cross section L formed
The difference is in the shape of the letters, and other points are the same as in the first embodiment, so the same members are given the same reference numerals and their explanations will be omitted.

That is, on the bottom surface of the accommodation groove 16 of the lens frame 15, a groove 21 is provided along the large-diameter circumferential wall on the large-diameter circumferential wall side thereof. Between the outer periphery of the lens 11 and the large-diameter circumferential wall of the housing groove 16 of the lens frame 15, there is a housing groove 16 that extends along the outer periphery of the lens 11 and the bottom surface of the groove 21, and that corresponds to the outer periphery of the lens 11. An L-shaped adhesive layer 19 forming a rectangular lens deformation absorbing space 20 is interposed on the large-diameter peripheral wall side of the housing. It is located in the same plane as the bottom surface of the groove 16.

In FIG. 4, reference numeral 22 denotes a ring-shaped space forming jig, and this space forming jig 22 is inserted into the lens frame 15 to form the lens deformation absorbing space 20.

Therefore, according to the second embodiment, similarly to the first embodiment, it is possible to easily and accurately position the lens 11 and the lens frame 15 in the radial and axial directions when assembling them. In addition, since the adhesive layer 19 can be easily elastically deformed in the radial direction, the lens 11 can be easily expanded in the radial direction due to temperature changes.
Shrinkage can be absorbed further.

In the second embodiment, the outer surface of the radially extending portion of the adhesive layer 19 is located in the same plane as the bottom surface of the housing groove 16, in other words, the end surface of the fitting protrusion 14. However, the present invention is not limited to this, the depth of the groove 21 is increased, and the adhesive layer 19 is
The outer surface of the radially extending portion of the lens 11 may be positioned below the end surface of the fitting protrusion 14 in FIG. can be absorbed even more.

FIG. 5 is a half-cut vertical cross-sectional view showing a third embodiment of the present invention, in which the first embodiment and the second embodiment are different from the end face of the fitting protrusion 14 and the bottom face of the accommodation groove 16. and the adhesive layers 17 and 19
is rectangular or L-shaped with the lens deformation absorbing space 20 provided above or on the large-diameter circumferential wall side of the housing groove 16, whereas At the same time, an elastic adhesive layer 23 is placed between the outer periphery of the lens 11 and the large diameter circumferential wall of the accommodation groove 16 on the side of the large diameter circumferential wall of the accommodation groove 16 corresponding to the outer periphery of the lens 11. The difference is that the cross section has an inverted T-shape in which a rectangular lens deformation absorbing space 24 is formed.

Note that other points are the same as those in the first and second embodiments, so the same members are given the same reference numerals and their explanations will be omitted.

Therefore, the third embodiment has the same effects as the second embodiment.

Note that in each of the embodiments described above, the lens frame 15
Although the case has been described in which the axial length of the small-diameter circumferential wall of the housing groove 16 is made smaller than the axial length of the large-diameter circumferential wall, the length is not limited to this, and both lengths may be made equal, or both lengths may be made equal. The length of can be reversed.

Furthermore, although each of the above embodiments has been described in the case where the lens frame is a single unit, the lens frame may also be a projecting edge integrally formed inside the lens barrel and projecting radially inward. Of course.

Effects of the Invention As described above, according to the present invention, it is possible to easily and accurately position the lens and the lens frame in the radial and axial directions when they are assembled, and the lens deforms due to temperature changes. This has the effect of being able to be absorbed by the adhesive layer or the like.

[Brief explanation of drawings]

1 and 2 are a longitudinal sectional view and an explanatory view of the prior art, respectively, FIG. 3 is a longitudinal sectional view showing a first embodiment of the present invention, and FIGS. It is a half-cut vertical cross-sectional view showing an example and a third example. DESCRIPTION OF SYMBOLS 11... Lens, 12... Lens main body, 13... Flange part, 14... Fitting protrusion, 15... Lens frame, 16... Accommodating groove, 17... Adhesive layer, 18... Lens deformation absorption space, 19... Adhesive layer , 20... Lens deformation absorbing space, 23... Adhesive layer, 24... Lens deformation absorbing space.

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 housing concave groove for accommodating the fitting protrusion of the lens is provided in a ring shape, and the inner peripheral wall of the fitting protrusion of the lens and the small diameter circumferential wall of the housing concave groove of the lens frame are fitted, and the outer circumference of the lens and the housing groove are fitted. A lens holding device characterized in that an elastic adhesive layer is interposed between a large-diameter peripheral wall of a concave groove to form a lens deformation absorbing space. 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, 2, or 3, wherein the adhesive layer has a rectangular cross section with a lens deformation absorbing space formed on the end surface side of the lens frame. . 5. The adhesive layer has an L-shaped cross section with a lens deformation absorbing space formed at least on the large-diameter peripheral wall side of the housing groove of the lens frame corresponding to the outer periphery of the lens. 3. The lens holding device according to item 1, 2 or 3. 6. The lens holding device according to claim 1 or 2, wherein the flange of the lens is in contact with an inner end surface of a lens barrel. 7. Items 1 and 2, wherein the adhesive layer has an inverted T-shaped cross section with a lens deformation absorbing space formed on the large-diameter peripheral wall side of the accommodation groove of the lens frame corresponding to the outer periphery of the lens. 6. The lens holding device according to item 6.