JPS62245209A - Holder for plastic lens - Google Patents

Abstract

PURPOSE:To prevent distortion and deformation even if there are expansion and shrink age by a temp. difference and to prevent the deterioration in the optical characteristics of a plastic lens by interposing a cushion ring having an elastic adhesive agent between the plastic lens and lens-barrel or adjacent lens and fixing the lens by the elastic adhesive agent. CONSTITUTION:The lens is held and fixed together with the cushion ring having a retaining ring and elastic adhesive agent by the lens-barrel 1 to hold the lens having a step 1a provided perpendicularly to the optical axis. A gap 1b is formed between the plastic lens 2 and the lens-barrel 1 holding said lens in the outside peripheral direction and the cushion ring 3 consisting of a soft material such as silicone rubber or polyurethane to hold and fix the lens 2 to the lens-barrel 1 is provided. Said ring has plural holes 4 in which the elastic adhesive agent 5 is packed. The adhesive agent 5 is composed of an acrylic resin, phenolic resin, etc. and the cushion ring is screwed to the lens-barrel 1 by the retaining ring 6 to press the lens 2. The ring 6 can be removed according to need after the lens 2 is adhered to the lens-barrel 1. The expan sion and contraction of the lens are absorbed by this constitution and the deterioration of the optical characteristics of the lens by the distortion and deformation is eliminat ed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a holding device for a plastic lens.

[Prior Art] In recent years, plastic lenses have come into widespread use in place of glass lenses due to their ease of manufacture, light weight, and low manufacturing cost. However, plastic lenses have a large coefficient of thermal expansion, and when a change in temperature or humidity occurs after they are held in a lens barrel, stress is generated between them and the lens barrel, causing distortion in the lens. To solve this problem, a technique has been proposed in which a plastic lens is fixed to a lens barrel using an elastic adhesive. A part or the entire circumference of the gap t formed between the outer peripheral surface and the inner peripheral surface of the lens holding cylinder 6 is filled with an adhesive 10 whose elastic modulus is smaller than that of the material of the lens 8 when solidified,
It is known that the lens 8 is fixedly held in the lens holding cylinder 6 (see Fig. 4.5).
8a represents a barrel portion of the lens 8, and 8a represents an abutment portion.

[Problem to be Solved by the Invention 1] However, in conventional lens holding devices that use adhesive to fix lenses, the adhesive may flow out before solidifying and adhere to the effective diameter surface of the lens. In addition to requiring wiping, if the filling amount of adhesive is minimized in order to eliminate this drawback, it will be difficult to thicken the adhesive layer, making it impossible to obtain sufficient elastic properties. Ta. This invention was made to solve the above-mentioned drawbacks of the conventional lens holding device, and even if the plastic lens expands or contracts due to temperature differences caused by heat, the plastic lens will not be distorted or deformed. It is an object of the present invention to provide a lens holding device that does not deteriorate the optical characteristics of the lens and prevents adhesive from flowing out onto the effective diameter surface of the lens.

[Step F for Solving the Problems] The lens holding device of the present invention is a plastic lens holding device for fixing a plastic lens to a lens barrel or an adjacent lens via an adhesive, in which the plastic lens and the lens mirror are fixed. A buffer ring having an elastic adhesive is interposed between the body and adjacent lenses, and the lenses are fixed with the elastic adhesive.

[Function] In this invention, a buffer ring having an unsolidified elastic adhesive 5 is interposed between a plastic lens and a lens barrel or a lens to hold the lens in the lens barrel. In this case, when the lens expands or contracts due to a temperature difference due to factors such as 8, the expansion or contraction of the lens is absorbed by the buffer ring 3 having an elastic adhesive.

[Example 1 Hereinafter, this invention will be explained in detail based on the drawings.

(First Embodiment) FIG. 1 is a cross-sectional view showing the first embodiment of the present invention, where l is a lens barrel for holding a lens having a stepped portion 1a provided perpendicularly to the optical axis; 11 with ring and elastic adhesive
Holds and fixes the lens together with the shock ring. Reference numeral 2 denotes a plastic lens, and a gap 1b is formed between the plastic lens and the held lens barrel 1 in the outer circumferential direction thereof. 3 is a buffer ring made of a soft material such as silicone rubber or polyurethane for holding and fixing the plastic lens 2 to the lens barrel l, and has a plurality of holes 4 for filling with an elastic adhesive. 5 is an acrylic resin type.

Phenol resin type, urea resin type, polyester resin type,
It is a rubber adhesive. Reference numeral 6 denotes a presser ring that presses the plastic lens 2 and is screwed onto the lens barrel l. Note that the holding ring 6 can be removed if necessary after the plastic lens 2 is adhered to the lens barrel 1.

The second @ is a perspective view showing the Il ring 3, where 4 is a plurality of holes drilled therein, and 5 is an elastic adhesive filled in the chain hole 4. still,
Instead of the holes 4 in the buffer ring 3, a plurality of recesses may be provided on the front and back sides of the buffer ring 3 and filled with the elastic adhesive 5 in the same manner.

(Second Embodiment) FIG. 3 is a cross-sectional view showing a second embodiment of the present invention, in which 2' is a lens used in combination with lens 2, and a centering point that narrows toward the outer periphery is set at the flange 2'a. It has an inclined surface 2'b.

A stepped portion lλ having an inclined surface corresponding to the inclined surface 2'b for centering the plastic lens 2' is formed on the inner periphery of the ila body 1.

The rest of the structure is the same as that of the embodiment shown in FIG. 1, so the same numbers will be given and the explanation thereof will be omitted.

In addition, in each of the above embodiments, the buffer ring 3 has each through hole 4 provided therein.
5 is shown filled with an elastic adhesive 5, but instead of each through hole 4, a plurality of recesses (not shown) are provided on the front and rear surfaces of the buffer ring body 3a, and each recess is filled with the elastic adhesive 5. It is also possible to configure the buffer ring 3 by
It is also possible to have a structure in which the oil-temperature soft material forming the material contains an adhesive in advance.

[Effects of the Invention] In this invention, a lens and a lens barrel or adjacent lenses are fixed by interposing a buffer ring having an elastic adhesive, so that the lens can be held by an adhesive layer having sufficient elastic holding ability. When holding the lens in the lens barrel, the adhesive does not flow out unnecessarily and stain the effective diameter surface of the lens, and even if the lens expands or contracts due to temperature differences, it can be held in the circumferential direction and optical axis direction of the lens. Both can absorb these expansions and contractions, and have the effect that the lens will not be distorted or deformed, which will not affect the optical properties of the lens.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a plastic lens holding device showing a first embodiment of the invention, FIG. 2 is a perspective view of a buffer ring used in the invention, and FIG. 3 is a sectional view showing a second embodiment.
4 and 5 are cross-sectional views showing conventional examples of lens holding devices. 1... Lens barrel tb... Gap 2.2'... Lens 3... Buffer ring 4... Hole 5... Elastic adhesive base Hp, -V@fu'' (N (co) one~

Claims (2)

[Claims] (1) In a plastic lens holding device for fixing a plastic lens to a lens barrel or an adjacent lens via an adhesive, a buffer ring having an elastic adhesive is provided between the plastic lens and the lens barrel or adjacent lens. 1. A plastic lens holding device characterized in that the plastic lens holding device is constructed by interposing the lens and fixing the lens with the elastic adhesive. (2) The plastic lens holding device according to claim 1, wherein the buffer ring has a plurality of through holes or recesses, and each through hole or recess is filled with an elastic adhesive.