JPH07191248A - Lens structural body - Google Patents

Abstract

PURPOSE:To provide a lens structural body which is capable of preventing generation of strain according to thermal deformation, permits easily assembling operation and exchange of the lens itself and is applicable to products of a small lot and high additive value. CONSTITUTION:The stress according to the thermal deformation of the lens 11 is absorbed by an elastic member 15 disposed between the outer circumference of the lens 11 and a holding ring 12 and, therefore, the generation of the strain in the lens 11 is prevented. Since the holding ring 12 is mounted at a holding frame 13, the removal of the lens 11 together with the holding ring 12 from the holding frame 13 is possible. Then, the easy exchange of the lens with another normal lens is possible even if a defect arises in the lens 11. The operation to inject an adhesive which is the elastic member 15 between the outside circumference of the lens 11 and the inside circumference of the holding lens 12 is carried out in a wide working space separately from the holding frame and, therefore, the assembling operation including the injecting operation is easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens structure which can be used in the vicinity of a high heat source or in an environment where the temperature changes drastically.

[0002]

2. Description of the Related Art Recently, plastic lenses have been widely used in optical systems. When this plastic lens is used in an optical system, when the lens expands due to heat, the lens is distorted due to the difference in linear thermal expansion coefficient between the lens and the fixing frame that fixes the lens, and the optical characteristics are impaired. Will end up. This tendency is particularly remarkable when used in a projector having a high heat source or in an environment where the temperature changes drastically.

[0003] Conventionally, as described in JP-A-59-135406, the outer peripheral surface of a lens and a holding frame for holding this lens have been proposed to solve the above-mentioned problems associated with the expansion and contraction of the lens due to heat. A rubber adhesive, whose Young's modulus is smaller than the material of the lens, is inserted as an elastic body in a part or the entire circumference between the inner peripheral surface of the lens and the lens and the holding frame are fixed by this elastic adhesive. I am trying to do it. Further, even if the lens is thermally deformed by expansion or contraction due to heat, the amount of this deformation is absorbed by the elastic body, so that the distortion of the lens due to this deformation stress can be prevented.

However, the work of injecting an elastic rubber adhesive between the outer periphery of the lens and the inner periphery of the holding frame must be performed in a narrow working space inside the holding frame, which makes the work difficult. Requires a lot of man-hours. Also, after the lens is fixed to the holding frame with an adhesive, it becomes impossible to remove this lens from the holding frame, and if a lens defect occurs, it is difficult to combine it with other lenses, and the unit price of parts It is disadvantageous for high small lots and high value-added products.

[0005]

As described above, in the conventional apparatus, since the lens and the holding frame are fixed by the elastic body, it is difficult to reassemble the lens, and the fixing work between the lens and the holding frame is difficult. It was difficult and required many man-hours.

The object of the present invention is to prevent the occurrence of distortion due to thermal deformation, to facilitate the assembling work, to easily replace the lens itself, and to apply it to small lots and high value-added products. It is to provide a possible lens structure.

[0007]

The lens structure of the present invention comprises:
A lens, a holding ring having an inner circumference facing the outer circumference of the lens with a gap, and an elasticity for fixing the holding ring and the lens with the gap between the inner circumference of the holding ring and the outer circumference of the lens. It is provided with a body and a holding frame for holding and fixing the holding ring at an inner portion.

[0008]

In the present invention, the elastic body provided between the outer circumference of the lens and the holding ring absorbs the stress caused by the thermal deformation of the lens, so that the lens can be prevented from being distorted and the holding frame can be held. Since it is attached via the ring, the lens together with the holding ring can be removed from the holding frame, and even if a lens defect occurs, it can be easily replaced with another normal lens. Since the work of injecting the adhesive, which is an elastic body, between and can be performed in a large work space separately from the holding frame, the work of injecting is facilitated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the lens structure of the present invention will be described below with reference to the drawings.

In FIG. 1 and FIG. 2, 11 is a lens made of plastic, and this lens 11 has a lens body 11a having a predetermined curvature and a flat collar 11b formed on the outer peripheral edge of the lens body 11a. Composed of and. Further, 12 is a retaining ring, which is made of a material whose linear expansion coefficient is lower than that of the lens 11, and which has an annular portion 12a having an inner diameter larger than the outer diameter of the lens 11 and a lower portion of the annular portion 12a. And an annular flange portion 12b integrally formed on the inner circumference.

The lens 11 is positioned in the radial direction of the lens 11 such that the distance between the outer circumference of the collar portion 11b and the inner circumference of the retaining ring 12 is uniform over the entire circumference. For, either side of the flange 11b is the flange
Positioned correctly by being placed on 12b.

Further, an adhesive agent serving as the elastic body 15 is injected into the space between the outer circumference of the collar portion 11b and the inner circumference of the retaining ring 12 to bond the collar portion 11b and the retaining ring 12 together. This adhesive cures after injection and functions as the elastic body 15. Such an elastic body 15 can be used as a lens in the state of use after assembly.
It is desirable that the lens 11 does not displace more than an allowable amount due to its own weight, and that the hardness of the lens 11 can absorb the amount of deformation without causing distortion when the lens 11 is thermally deformed. Good.

The outer circumference of the holding ring 12 is fitted and held by the inner circumference of a ring-shaped or cylindrical holding frame 13, and the holding frame 13 is made of a material having a linear expansion coefficient equivalent to that of the holding ring 12. , The retaining ring 12 and the lens 11 adhered to the retaining ring 12.
Are positioned in the radial direction of the lens 11. Further, as shown in FIG. 1, a horizontal flange portion 13a is provided on the inner circumference near the end portion of the holding frame 13, and the flange portion 13a is provided.
The upper surface of 13a supports the lower surface of the flange portion 12b of the retaining ring 12.

Further, a screw groove 13b is threaded on the inner circumference of the end of the holding frame 13, and a retaining ring is formed in the screw groove 13b.
The outer circumference of 14 is screwed. Then, the lower surface of the pressing ring 14 is joined to the upper edge of the annular portion 12a of the retaining ring 12 to form the flange portion.
The retaining ring 12 is clamped from above and below together with 13a, and the retaining ring 12
The lens 11 adhered to is positioned in the thrust direction, which is the optical axis direction. That is, the lens 11 has a retaining ring 12
It is held and fixed in the holding frame 13 in a predetermined positional relationship via.

Here, the lens 11 needs to be positioned with respect to the holding ring 12 so that the outer circumference of the lens 11 and the inner circumference of the annular portion 12a are evenly spaced over the entire circumference. This positioning uses the built-in jig 16 shown in FIGS. 3 and 4.

As shown in FIG. 3, the assembling jig 16 has a plurality of positioning members 17 arranged at equal intervals in the circumferential direction of the retaining ring 12, Three positioning tools 17 are provided at 120 ° intervals with respect to the circumferential direction. As shown in FIG. 4, these positioning tools 17 are positioned in a normal state such that an inner peripheral wall 17a fitted to the outer circumference of the retaining ring 12, a holding portion 17b that abuts on the upper edge of the annular portion 12a of the retaining ring 12, and a holding portion 17b. And a shoulder pressing portion 17c that fits into the upper corner portion of the outer periphery of the lens 11.

In the above structure, when the lens 11 is attached to the holding frame 13, the lens 11 is first bonded to the holding ring 12 via the elastic body 15. In this case, the lens 11 is attached to the flange portion 12b of the retaining ring 12 as shown in FIGS.
Place it on the top and insert the assembly jig 16 from above. And
By this operation, the lens 11 and the retaining ring 12 are positioned and fixed by the inner peripheral wall 17a of the positioning tool 17, the pressing portion 17b, and the shoulder pressing portion 17c in a regular state with an even interval over the entire circumference.

In this way, after being fixed in the proper positioning state, an adhesive that becomes the elastic body 15 is injected between the outer circumference of the lens 11 and the inner circumference of the retaining ring 12. This adhesive bonds between the lens 11 and the retaining ring 12 after injection,
It is hardened to have a predetermined elastic force, and elastically supports the lens 11 in its radial direction. That is, the cured adhesive
Reference numeral 15 is an elastic body interposed between the lens 11 and the retaining ring 12.

Next, a retaining ring 12 having a lens 11 bonded inside
Is fitted inward from the end of the holding frame 13. By this operation, as shown in FIG. 1, the holding ring 12 is in a fitted state in which the lower surface of the flange portion 12b is placed on the flange portion 13a in the holding frame 13. In this state, the holding ring 12 and the lens 11 bonded to the holding ring 12 are positioned and fixed by the inner circumference of the holding frame 13 in the radial direction.

Next, the pressing ring 14 is screwed into the thread groove 13b formed on the inner circumference of the end of the holding frame 13. As a result of this operation, the upper edge of the annular portion 12a of the retaining ring 12, as shown in FIG.
The holding ring 12 is joined to the lower surface of 14 and is sandwiched from above and below by the flange portion 13a and the holding ring 14. Therefore,
The holding ring 12 and the lens 11 bonded to the holding ring 12 are
It is also positioned in the thrust direction by the holding frame 13.

In this state, when heat is applied to the lens 11 from a high heat source or the like, the plastic lens 11
Expands in both radial and thrust directions. Since the retaining ring 12 and the retaining frame 13 are also heated, the retaining ring
12 and the holding frame 13 also expand, but the linear thermal expansion coefficient of the lens
Since it is smaller than 11, it does not expand as much as the lens 11, and a difference in expansion amount occurs between the lens 11 and the lens 11. However, lens 11 and retaining ring
An elastic body 15 in which an adhesive is cured is interposed between the elastic body 12 and 12, and the difference in expansion amount in the radial direction is absorbed by the elastic body 15 in which the adhesive is cured. In the thrust direction, the holding ring 14 only holds the holding ring 12, and the lens 11 receives no restraining force, and thus can freely expand. As a result, the lens 11 is not distorted due to the stress associated with thermal deformation, and stable optical characteristics can be obtained.

As described above, since the optical design can be performed without considering the deformation amounts of the holding frame 13 and the lens 11 due to heat, the optical system can be stabilized. It is especially effective for large aspherical lenses. In addition, the range of application of the plastic lens with respect to temperature is expanded, which contributes to stabilization of optical performance.

Further, when a defect occurs in the lens 11, the lens cannot be removed from the holding frame by the conventional structure in which the lens is directly fixed to the holding frame. However, according to the above embodiment, the lens 11 is held. Since it can be removed from the holding frame 13 together with the ring 12, the defective lens can be removed and arbitrarily replaced with a normal lens. That is, when the defective lens 11 is incorporated in the holding frame 13 as shown in FIG.
The holding ring 14 is removed from the end portion of the holding frame 13 by rotating 14 in the opposite direction to that at the time of screwing.

As described above, after the pressing ring 14 is removed, the holding ring 12 to which the lens 11 is attached is attached to the holding frame in the fitted state.
It can be freely removed from inside 13. Therefore, remove the defective lens 11 together with the retaining ring 12 from the inside of the retaining frame 13,
The normal lens 11 is fitted into the holding frame 13 together with the holding ring 12 adhered by the method described in FIGS. 3 and 4,
Further, by screwing the presser ring 14, the mounting of the lens 11 in the holding frame 13 is completed. That is, the lenses can be recombined arbitrarily and easily like replacement of a defective lens with a sound lens, which is effective for a small lot and a high value-added optical system. Further, since such a structure does not require any processing on the lens itself, it can be immediately applied to various existing lenses.

The assembling jig 16 shown in FIGS. 3 and 4 is also used.
Positioning work with the lens 11 and the retaining ring 12 using
The work of injecting the adhesive that becomes the elastic body 15 into the space between the lens 11 and the holding ring 12 can be freely performed in a wide working space separated from the holding frame 13. For this reason, the workability is remarkably improved as compared with the conventional work in a narrow holding frame, so that the number of work steps can be significantly reduced.

[0026]

According to the lens structure of the present invention, the elastic body provided between the outer circumference of the lens and the retaining ring absorbs the stress caused by the thermal deformation of the lens, so that the lens can be prevented from being distorted and held. Since it was attached to the frame via the retaining ring, the lens together with the retaining ring can be removed from the retaining frame, and even if a lens defect occurs, it can be easily recombined and replaced with another normal lens, Since the work of injecting the adhesive, which is an elastic body, between the outer circumference of the lens and the inner circumference of the holding ring can be performed in a wide working space separately from the holding frame,
The injection work can be done easily.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a lens structure of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a plan view showing the relationship between the assembling jig and the lens and the retaining ring.

FIG. 4 is a sectional view of the same.

[Explanation of symbols]

 11 Lens 12 Holding ring 13 Holding frame 15 Elastic body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Youji Kubota 1-21-17 Takashima, Suwa City, Nagano Chinon Corporation

Claims (1)

[Claims] 1. A lens, a retaining ring having an inner periphery facing the outer periphery of the lens with a gap, and a retaining ring and a lens interposed between the inner periphery of the retaining ring and the outer periphery of the lens. A lens assembly, comprising: an elastic body for fixing the spaces between them; and a holding frame for holding and fixing the holding ring at an inner portion.