JPS5975217A - Lens holder - Google Patents

Abstract

PURPOSE:To prevent the focus deviation of a plastic lens system due to temperature by holding a lens through a clamping part which performs hinge operation and is provided to one end of an arm part fixed at the other end in a lens frame and extending at a specific angle to an optical axis. CONSTITUTION:A lens body 20 is fallen in the lens frame 30 and a fixed part 23 is locked to a lock edge 32; and a presser ring 40 is screwed into a screw part 31 through its screw part 41 and thus the fixed part 23 is pressed fixedly against the lock edge 32 by the presser ring 40 to hold the lens 212 inside of the lens frame 30. When this lens frame 30 and lens body 20 are held at a temperature higher than specific temperature, the coefficient of linear expansion of the lens is greater than the lens frame 30 because the lens 21 is made of resin and it expands radially in the lens frame 30; and each arm part 22 expands radially and elastically to move the lens in the optical-axis direction, but the focus movement of the lens system is corrected by the axial movement of the lens 21 at the temperature where the lens 21 and arm part 22 are easily variable in relative angle by the hinge effect of the clamping part 24.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens holding device that holds a lens in a frame, and in particular, a lens holding device that holds a lens in a frame so that a plastic lens with weak temperature resistance does not change its shape even when the temperature changes [9]. This aims to maintain lens performance and provide a lens system with strong temperature resistance, as well as to expand the operating temperature range of plastic lenses and other lenses without temperature resistance.

Conventionally, when a lens, for example a plastic lens 7, is mounted in the I frame 2, as shown in FIG. At the same time, fit the plastic lens 7 into the lens frame fitting part 5 while touching the lens frame 2, and attach the outer periphery VC of the presser foot 1 to the φ frame threaded part 3 screwed to the inner periphery VC of the casting flask 2! lI! ! The presser foot 1 is screwed into the inside of the holding frame 2 while screwing together the threaded portion 6 provided, and the presser foot 1 is brought into contact with the plastic lens 7 formed on the inner periphery of the presser ring l @ 1 a f The front side of the plastic lens 7 The plastic lens 7
It is constructed by fixing it within the Zensui 2.

After assembling the plastic lens 7 to the lens frame 2 at room temperature, the linear expansion coefficient of the original material of the plastic lens 7 was Since the coefficient of linear expansion is larger than the linear expansion coefficient of the molding material of the frame 2 and the presser ring 1, the lens frame section s5 in the chain portion 2
clearance becomes smaller.

Furthermore, what is most noticeably affected by this is the portrait of the lens 7 and the presser ring 1 in FIG. 1a? Vi 8 (see the enlarged view shown in Figure 1), the clearance is already zero when the parts are assembled at room temperature, and the lens This means that the difference in the coefficient of linear expansion of the original material for the presser ring IVr and the presser ring IVr directly affects the surface shape.

That is, at the abutting portion 8 of the lens 7 and the presser ring 1, the outer circumferential edge 7b on the front side of the lens 7, which the abutting edge 1a of the presser foot 1 presses against, is depressed, and the abutting edge 1a of the presser ring l causes the lens to 7 or be regulated to zero clearance.

Once, as the temperature increases, the plastic lens 7 begins to expand in the radial direction, but the restriction by the holding mound 1 restricts the deformation of the plastic lens 7 in the radial direction. Thermal stress occurs internally.

Then, the thermal stress generated inside the plastic lens 7 concentrates on unregulated deformation in the optical axis direction, causing the plastic lens 7 to deform in the optical axis direction.

Considering the cross section in the axial direction including the optical axis of the plastic lens 7, since the length of the chord AB in CVc in FIG. becomes smaller.

Now, if the arc length at room temperature is iAB, and the coefficient of linear expansion at t°C than at room temperature is α, then the following is approximated.

Conversely, when the plastic lens 7 and the lens frame 2 assembled together at room temperature are exposed to a low-temperature atmosphere, the linear expansion coefficients of the molding materials of the plastic lens 7, the φ frame 2, and the presser ring 1 differ as described above. Therefore, as the temperature decreases, the plastic lens 7 shrinks more than the lens frame 2 and the presser ring 1, and the plastic lens 7 tends to shrink more than the lens frame 2 and the presser ring 1. Front side outer peripheral edge 7b of plastic lens 7 fixed by pressure contact of contact edge 1a of ring 1
As a result of the regulation, the plastic lens 7 cannot contract more than the contraction of the presser foot 311, as in the case at high temperatures, and thermal stress is generated inside the plastic lens 7, and this thermal stress Concentrates in the optical axis direction of the plastic lens 7, which is not restricted by the presser foot 1,
Giving the original axial direction Kf shape of the plastic lens 7K
Become.

Therefore, considering the axial cross section of the plastic lens 7 including the optical axis shown in FIG. As a result, the radius of curvature becomes too large.

Now, if the arc length at room temperature is AB - the linear expansion coefficient of the molding material 1°C lower than room temperature is α.

Approximate to

Therefore, from the above points, when the plastic lens 7 is held and mounted within the lens frame 2 having a conventional structure, the radius of curvature of the plastic lens 7 changes due to temperature changes. In other words, it is clear that it becomes smaller at high temperatures and becomes larger at low temperatures, and the focus position shifts significantly compared to at room temperature. It can be seen that this causes deterioration of the r-ridge aberration.

In addition, as a lens holding device of this type, Japanese Patent Application Laid-Open No. 57-1
The inventions disclosed in No. 38603 and Japanese Unexamined Patent Publication No. 57-138606 have been disclosed.

The former lens holding device has a ψ frame 2, as shown in Fig. 1e.
The plastic lens 7 housed inside the fitting part 5 of the lens frame 2 is held while the screw part 6 screwed on the outer periphery of the presser foot 1 is screwed into the Φ frame screw part 3 screwed on the inner peripheral surface of the lens frame 2. , tf5K, instead of fixing the main body of the plastic lens 7 directly by pressing fMIK as shown in FIG. A deformation absorbing material 11 made of a highly elastic material is provided on the outer periphery of the material, and a presser foot 1 is provided.
The fitting portion 12, 13 of the deformation absorbing material 11 of the plastic lens 7 and the thin wall around the lens are both on the lens body portion 4 of the Q frame 2! 14) is constructed by providing ten clamping parts 14 and 15.

Then, use the presser ring 1 to hold the plastic lens 7 in
When fixing the deformation absorber 11 inside the holding ring 1 and the fitting part 12.13 of the lens I]lff1 attaching m4, the lens peripheral thin part 10 is held between the holding ring 1 and the lens body part 4. It is held between the holding parts 14 and 15 and fitted between the holding ring 1 and the lens body part 4.

The plastic lens is held in the fitting part 5 of the frame 2 via the deformation absorbing material 11 held therebetween and the lens peripheral thin wall part 10.

The latter lens holding device is constructed by fitting a deformation absorbing material 16 around the outer periphery of the plastic lens 7, as shown in FIG. A presser foot collection IK in which the deformation absorbing material 16 fitted around the outer periphery of the lenses 7 is screwed onto the screw portion 317r of the lens frame 2.
By pressing and fixing the plastic lens 7 closer to the lens assembly portion 4 side, the plastic lens 7 is held within the lens 2 via the deformation absorbing material 16.

Now, when this lens system is brought to a high temperature state, compressive stress will be generated in the lens 7 due to the difference in the expansion coefficient of the lens 7 material and that of the lens frame 2 material. Therefore, deformation tends to occur near the minimum cross section of the lens 7. However, the deformation absorbing material 1 between the lens 7 and the lens frame 2
Since the lens 1.16 deforms first, the deformation of the lens 7 itself is reduced. The same thing can be said when the temperature is low.

However, simply keeping the distortion of the lens part small in this way does not take any measures against changes in refractive index and curvature due to temperature of the lens, and when considered as a lens system, the focus of the lens system changes due to temperature. Defense + EK has little effect.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens holding device that eliminates the unresolved drawbacks of the conventionally known lens holding devices as described above, and at the same time achieves desired effects with an extremely simple structure.

Hereinafter, the lens holding device according to the present invention will be explained in detail with reference to specific embodiments shown in the drawings.

FIGS. 2a and 2b are a partially omitted longitudinal sectional side view and a longitudinal sectional front view taken along the line A--A in the same figure, showing the first embodiment of the present invention.

In the lens holding device in the first embodiment, 2
Reference numeral 0 designates a lens body, and this lens body 20 has arm portions 22 projecting from the outside of a plastic lens 21 as a lens to be held at four locations spaced apart from each other in the circumferential direction.

Further, each arm portion 22 is provided with an outer end 228 [fixing portion 23 with the lens frame 30 and the plastic lens 22].
1 and the protruding base L' 1522b [a narrow part 24 with a hinge action is provided, and as shown in FIG. 2 aVC, this narrow part 24
The fixed m is now 230,000 times.

It is formed while giving the required angle with the optical axis.

Moreover, when each arm portion 22 is viewed from the front in FIG. 2, the protruding base portion 22b has a trapezoidal shape, and the main body has a long sword shape with a required width, and when viewed from the side in FIG. 2a, The fixing part 23 has a rectangular shape consisting of the required -I squares, and also has a triangular shape whose wall thickness gradually decreases from the fixing part 23 toward the narrow part 24.

Therefore, the plastic lens 2 consisting of these structures
1 and each arm s22 are integrally formed.

30 is a lens frame, and the screw part 3 of the presser foot fJI40 is attached to the inner periphery.
1 is threaded, and a locking edge 32 that locks the fixing portion 23 of each arm portion 22 of the lens body 20 is fully protruding.

The retainer ring 40 is made of a ring body, and a threaded portion 41 is provided on the outer periphery of the retainer ring 40 to be screwed into the screw m311c of the lens frame 30.

Now, when holding the lens body 20t constructed as described above in the lens frame 30, the lens body 20 is dropped into the lens frame 30, and the fixing 923 of each arm portion 22 is fixed at the locking edge of the lens frame 30. 32 and by screwing the threaded part 314 of the lens frame 30 and the holding ring 40 through the threaded part 41, the fixing part 23 of each arm part 22 is pressed and fixed to the locking edge 32 by the holding ring 40. urge

Therefore, the plastic lens 21'i and the frame 3 are attached to the lens body 20 via each arm portion 22 fixed with the presser ring 40.
It is possible to hold it inside 0.

The lens body 20 is made of the same synthetic resin, and the plastic lens 21. It is also possible to mold the arm portion 22 and the narrow portion 24 using different synthetic resins in two colors.

Next, FIG. 3 is a partially omitted vertical sectional side view showing a second embodiment of the present invention.
Is it the same as the first embodiment shown?

The structure of the lens body 20 is different, and each Pld
It is constructed separately from the m22''k plastic lens 21 and is connected to the two.

That is, a connecting convex portion 25 is provided on each protruding base portion 22b on the outside of the plastic lens 21 (same position as shown in FIG. 2 bvc), and a connecting concave portion is provided at the end of the narrow portion 24 of each arm portion 22. 26 is provided.

Thus, the connecting concave portions 26 of each arm portion 22 are connected to the connecting convex portions 25 of the plastic lenses 21 which are formed separately.
'Jk is firmly fitted, and each arm part 2 is attached to the plastic lens 21.
The lens body 20 is constructed by attaching the lens 2.

The other structure of each arm s22 is exactly the same as that of the first embodiment, and the lens body 20't having the above structure is held inside the lens frame 30 by a presser ring via each arm part 22. Since the same is true for , the explanation thereof will be omitted.

FIG. 4 is a partially omitted vertical sectional side view showing a third embodiment of the present invention.

In the lens holding device in this embodiment, by fixing the fixing part 23 of each arm s22 of the lens body 20 with a presser ring 40 screwed into the threaded part 31 of the lens frame 30,
A plastic lens 21 as a lens to be held is attached to a lens frame 3.
The basic structure held inside the lens body 20 is completely the same, but the structure of the lens body 20 is different from that of the first embodiment.

That is, the narrow portion 24 of each arm portion 22 having a hinge function is provided at the end with the fixed portion 23, and each arm portion 22 is rotatably connected to the outside of the plastic lens 21 via the link portion 27. It is composed of

The link part 27 has a fitting recess 28 at the end of each arm part 22, and a spherical fitting convex on each protruding base 22b (same position as f& shown in FIG. 2) on the outside of the plastic lens 21. A fitting concave portion 28 of each arm portion 22 is rotatably fitted into each fitting convex portion 29.

FIG. 5 is a partially omitted vertical sectional side view showing a fourth embodiment of the present invention, in which the fixing part 23 of each arm part 22 of the lens body 20 is connected to the screw of the lens frame 30, as in the first to third embodiments. The basic structure of holding the plastic lens 21 as a lens to be held inside the lens frame 30 by fixing it with a presser ring screwed into the part 31 is the same, but the structure of the lens body 20 is different.

Further, the configuration in which each arm portion 22 is rotatably connected to the plastic lens 21 by a link portion 27 is the same as that of the third embodiment shown in FIG. Instead, the shape of the arm main body 22C is made into the same thin shape to enable elastic deformation, and this main body 220
(It is constructed by giving itself a hinge action similar to the hinge action at the narrow part 24 of the other arm 1++22)
Ru.

Now, the lens holding device according to the present invention has the above-mentioned configuration, and its operation will be explained below.

When the lens body 20 and the lens body 20 configured in this way are moved from a certain temperature to a higher temperature, the plastic lens 21 is made of resin, so its r1 linear expansion coefficient is larger than that of the lens frame 30 (usually aluminum), and the lens body 30 It expands in the radial direction as shown by the broken line in Figure 2a. At this time, each arm portion 22 is elastically deformed and the second
As shown in Figure aK, the plastic lens 21 is expanded in the radial direction and moved in the original axial direction. At this time, the relative angle of the lens 21 and the arm portion 22 can be easily changed due to the hinge effect of the narrow portion 24. By moving the lens 21 in the axial direction due to this temperature, the focus sh due to the temperature of the lens system can be corrected.

The amount of correction can be set to various values depending on the angle of each arm 22 with respect to the optical axis and the length of the arm.

Further, when the temperature becomes lower than a certain temperature, the diameter of the lens 21 contracts, and the lens 21 is corrected while moving in the opposite direction to that when the temperature is high.

In the above embodiment, the case where each arm part 22 is provided at four locations on the outer periphery of the plastic lens 21 has been explained, but it can also be provided at three locations, and the design can be carried out within a range that effectively obtains the intended effect. The fixing part 23 of each other arm part 22 is changeable. Narrow 924. IJ link part 27
The configurations described above are not limited to the illustrated embodiments, and may be implemented with various design changes.

According to the lens holding device of the present invention, the lens to be held is held by the arms 22 that protrude obliquely at a predetermined angle inside the lens 30, so that the expansion and contraction of the lens 21 to be held due to temperature changes can be prevented by each arm. By absorbing this by deforming the portion 22 and moving the held lens 21 in the axial direction as each arm portion 22 deforms, it is possible to obtain the effect of correcting the focus shift due to the temperature of the lens system.

Again, the narrow portion 24 is provided at the boundary between the arm portion 22 and the held lens 21, and its hinge effect has the effect of smoothing the movement of the lens in the axial direction due to temperature.

Furthermore, as in the second embodiment, the arm portion 22 and the lens 21t? When each part is formed and configured separately, the intended function of each part can be further improved by being made of different materials.

%KQ style 30 and each arm 22. By providing a hinge mechanism and a link mechanism in the narrow portion 24 and the link portion 27 to connect the lens 21 and the arm portion 22, it is possible to further smooth the actions of each portion as the lens moves due to temperature changes.

Moreover, by expanding the elastically deformable portion of the main body 22C of each arm 22 without providing the narrow m24t with a hinge effect, stress concentration and fatigue occurring in the narrow s24 can be avoided.

[Brief explanation of drawings]

Fig. 1 shows a conventional lens holding device, Fig. 1a is a central vertical sectional side view, Fig. 1 is an enlarged view of section A in Fig. 1a, and Fig. 1c and d are in Fig. 1a. An explanatory diagram showing the deformation state of the lens to be held in the lens holding device at high and low temperatures with respect to normal temperature, FIGS. Fig. 2 is a longitudinal sectional side view showing one example omitted, showing an example, Fig. 2 is a longitudinal sectional front view taken along line A-A in Fig. 2a, and Figs. It is an abbreviated vertical side view. 20...Lens body 21...7@lastic lens 22...Arm part 23...Fixing part 24...Narrow part 25...Convex part for connection 26...Concave part for connection 27. ... Link part 28 ... Recessed part for fitting 29 ... 6-tone l5 for fitting 30 ... Kaneki 31 ... Threaded part 32 ... Locking green 40 ... Presser foot 41 ... Screw Department. Patent Applicant Olympus Optical Industry Co., Ltd. Representative Patent Attorney Takeshi Naa -19- Figure 1 (Q)? 1 (b) Figure 1 Figure 2 (0) (f) (b) Procedural amendment (0 Kaji) February 4, 1981 Kazu Wakasugi, Commissioner of the Patent Office Failure 1, case indication Showa 5T year register Patent Application No. 186583 Name of Invention 2 Lens Holding Device 3, Relationship to the Case of Person Who Makes Correction Patent Applicant Address 2-43-2 Hatagaya, Shibuya-ku, Tokyo Name) (037) Olympus Optical Industry Co., Ltd. Company Registrar and President Shigeo Kitamura 4, Agent Name (6942) Patent Attorney Takeshi Nara 5,
Date of amendment order 6, number of inventions increased by amendment 7, object of amendment 5i-= column 8 of “W#-m explanation of invention”, content of amendment (1) Specification No. 17 Shell No. 5 "In the case that it was constituted" in the second line is amended to "in the case that it was constituted."

Claims (1)

[Claims] (1) An arm portion whose one end is fixed within the Confucian frame and extends at a required angle to the optical axis, and a narrow portion provided with a hinge function at the other end of the arm portion. A lens holding device is released from the lens held through the narrow part of this arm. (21) One end is fixed in the Confucian frame, and an arm is provided at the required angle with respect to the optical axis through a narrow part with a hinge function at this end, and an arm is provided at the other end of this arm. A lens holding device consisting of a link part of the arm part and a lens held through the link part of the arm part. A lens holding device consisting of a deformable arm, a link provided at the other end of this arm, and a lens held via the link of this arm. (4) One end of the arm is The lens holding device according to claim 1, 2, or 3, which is fixed by a presser ring screwed onto a threaded portion of the lens. (5) The arm portion is formed integrally with or separately from the lens. The lens holding device according to claim 1, comprising: (6) The link portion of the arm portion includes a recess for engagement with a spherical protrusion protruding from the outer periphery of the lens. The lens holding device according to item 2 or 3.