JPS58125004A - Lens holding device - Google Patents

Abstract

PURPOSE:To obtain a lens holding device which has a high resistance to the variation of temperature, by interposing an elastic member consisting of a synthetic resin between the inside of a mirror frame and the outside of a plastic lens. CONSTITUTION:In case that a plastic lens 30 is held in a fitting part 21 of a mirror frame 20, a deformation absorbing sleeve 40 as an annular elastic member is interposed between the inside of the fitting part 21 and the outside circumference of the plastic lens 30, and the plastic lens 30 is set to the inside of the fitting part 21 of the mirror frame 20. A press ring 24 is engaged with a screw part 23 of the mirror frame 20, and a holding edge 31 on the outside circumference of the plastic lens 30 is fitted by a pressing edge 26 of the press ring 24 while pressing one side face 31a of the holding edge 31 to the other side face 31b engaged with a body part 22 of the fitting part 21, and thus, the plastic lens 30 is held.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens holding device that absorbs temperature changes within a lens frame of a lens such as a plastic lens by a structure that holds the lens.

Improved so that the original performance of the lens can be demonstrated normally without being affected by temperature changes inside the lens frame, and is used to improve the temperature resistance of lenses with poor temperature resistance such as plastic lenses. In order to expand the scope of counterfeiting, lll1t
The purpose of this invention is to make it possible to construct and provide a lens system with strong temperature resistance.

Conventionally, when a lens, for example a plastic lens 1, is mounted in a lens frame 2, as shown in FIG. Fit the plastic lens 1 into the lens frame fitting part 4 while making contact with each other, and screw the threaded part 7 threaded onto the outer periphery of the presser ring B into the lens frame threaded part 5 threaded onto the inner periphery of the lens frame 2. while screwing the retaining ring 6 into the inside of the lens frame 2, and pressing the abutting edge 8 formed on the inner peripheral edge of the retaining ring 6 against the plastic lens 1 to the outer peripheral edge 1b on the front side of the plastic lens 1, It is constructed by fixing the plastic lens 1 within the lens frame 2.

Now, when the plastic lens 1 consisting of four components is assembled to the lens frame 2 at room temperature and then exposed to a high temperature atmosphere, the coefficient of linear expansion of the molding material of the plastic lens 1 is Since the coefficient of linear expansion is higher than that of the molded materials of the holding ring 2 and the presser ring 6, the clearance of the lens frame fitting portion 4 in the lens frame 2 becomes smaller.

Furthermore, this effect is most noticeable at point A where the lens and presser ring contact each other in Figure 1a (see the enlarged view shown in Figure 1A); The clearance is already zero, and in the high-temperature atmosphere, the difference in linear expansion coefficient of the molded wood in the lens 1 and the presser ring 6 will directly affect the surface shape. .

In other words, (
- Make a dent in the outer peripheral edge 1b of the front side of the lens 1, which the contact edge 8 of the presser ring 6 comes into pressure contact with.

In addition, the contact edge 8 of the presser ring 6 restricts the lens 1 to a state of zero clearance.

Therefore, as the temperature increases (・), the plastic lens 1 begins to expand in the radial direction, but the deformation of the plastic lens 1 in the radial direction is restricted by the restriction by the presser ring 6. lens 1
Thermal stress occurs internally.

Then, the thermal stress generated inside the plastic lens 1 concentrates on unregulated deformation in the original axis direction, causing the plastic lens 1 to deform in the optical axis direction.

Considering the cross section in the axial direction including the original axis of the plastic lens 1, since the length of the chord AB in FIG. becomes smaller.

Now, suppose that the length of the arc at room temperature is AB, the length of the arc at t'C higher than room temperature is A'B', and the #expansion rate of the plastic lens 1 is α.

A’B’i:=AB　−(1+αt) Approximate to

Conversely, when the plastic lens 1 and 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 1, lens frame 2, and presser ring 6 differ as described above. Therefore, as the temperature decreases, the plastic lens 1 contracts more than the lens frame 2 and the presser ring 6, and tends to shrink more than the lens frame 2 and the presser ring. The outer peripheral edge 1b on the front side of the plastic lens 1 is fixed by pressing the contact edge 8 of the ring 6.
As a result, as in the case of high temperatures, the plastic lens 1 cannot contract more than the contraction of the presser ring 6, and thermal stress is generated inside the plastic lens 1. is concentrated in the optical axis direction of the plastic lens 1 and is not restricted by the presser ring 6, causing deformation of the plastic lens 1 in the optical axis direction.

Therefore, let us consider the axial direction including the optical axis of the plastic lens 1 shown in FIG. 1d.

Since the length of the string AB is regulated by the presser ring 6, the collection concentrates on the arc AB, and as a result, the radius of curvature becomes larger.

Now, if the length of the arc at room temperature is AB, the length of the arc at t°C lower than room temperature is AB, and the coefficient of linear expansion of the molding material of plastic lens 1 is α, then A'B'≧AB・(1+αt) Approximate to

For the reasons mentioned above, when the plastic lens 1 is mounted in the lens frame 2 having a conventional structure using a presser ring, the radius of curvature of the plastic lens 1 changes by two degrees due to temperature changes. -f'rope'? ) It is clear that it is small at high temperatures and becomes large at low temperatures, and it is also clear that the focal position shifts significantly and each aberration worsens compared to at room temperature.

In addition, in the configuration of the conventional lens and lens frame (・), the first
As shown in FIG. A composite lens configured to reduce the frictional resistance between the two lenses 12 and 13 that are adjacent to each other by their outer peripheral edges, and to prevent misalignment of the lenses between the two lenses 12 and 13. However, in the case of this configuration, the friction between the two lenses 12, 13 is only reduced, and the lenses 12, 13 are placed at a low joint. The structure in which the lens 11 is fixed by the presser ring 15 is similar to the conventional structure described above, and the lens 1
2.13 is the outer diameter of the fitting part 1 of the lens holding member 10.
1 or the inner diameter of the holding mound 15, and similarly to the plastic lens 1, it is not possible to prevent changes in the radius of curvature of both lenses 12 and 13 due to temperature changes, and the focus position shifts due to temperature changes. It is impossible to reverse the deterioration of aberrations.

Therefore, in the conventional lens mounting configuration for the lens frame, changes in the radius of curvature caused by temperature changes can be prevented, and focus position deviations can be prevented. The development of retention structures or other appropriate measures was in great need.

Therefore, in the present invention, when a plastic lens is held within a lens frame, an elastic member made of synthetic resin is interposed therebetween.

The conventional lens holding device has been improved, and the elastic member absorbs changes in the radius of curvature caused by temperature changes of the plastic lens held in the fitting part of the lens frame, and the focal position changes due to temperature changes of the plastic lens. This prevents movement and deterioration of aberrations, and also expands the operating temperature range of plastic lenses.

Hereinafter, an embodiment of the lens holding device according to the present invention will be described in detail with reference to FIG.

FIG. 2a is a 1u11 sectional view showing the first embodiment of the present invention,
The figure is a front view of the deformation absorbing sleeve.

20 is a lens frame, 21 is a fitting part of the plastic lens 30 provided inside the lens frame 20, and this fitting part 21 has a barrel attachment part 2.
2 is provided.

23 is a threaded part screwed on the inner peripheral surface of the closing frame 20, and 24 is a threaded part 23 of the lens frame 20.

Plastic lens 3 fitted into fitting part 21 of lens frame 20
This is an annular holding ring that holds 0. A threaded part 25 corresponding to the threaded part 23 of the lens frame 20 is threaded on the outer periphery of this holding ring 24, and a pressing edge 26 of the plastic lens 30 is screwed on the inner periphery. By providing it, it is integrally formed.

Therefore, when holding the plastic lens 30 in the fitting part 21 of the lens frame 20, a deformation absorbing sleeve 40 as an annular elastic member is interposed between the inside of the fitting part 21 and the outer peripheral side of the plastic lens 30. Then, plastic lens 3
0 inside the fitting part 21 of the lens frame 20, and screw the presser ring 24 onto the threaded part 23 of the lens frame 20.
Holding m31 on the outer circumferential side of the plastic lens 30 by the pressing edge 26 of No. 4, one side surface 31& of the other side 11111 and 31b engaging with the body attachment portion 22 of the fitting portion 21.
Also, by pressing it to the side and pinching it. The deformation absorbing sleeve 40 as the annular elastic member has a fitting part 41 with the frame 2o having an outer diameter corresponding to the inner diameter of the fitting part 21 of the lens frame 2o, and also has a fitting part 41 on the inner peripheral side of the fitting part 41. A fitting part 42 with a plastic lens having an inner diameter corresponding to the outer diameter of the plastic lens 30 is provided along the 9. The elastic modulus of the molding material of the plastic lens 30 which is preferably made of synthetic resin and which is to be held is provided. It is integrally formed from a material with a lower modulus of elasticity.

Therefore, the deformation absorbing sleeve 40
The fitting part s42 of the plastic lens 30 is externally fitted onto the plastic lens 30, and the fitting part s41 on the outside thereof is fitted into the fitting part 21 of the lens frame 20, and the plastic lens 30 is inserted into the plastic lens 30 by fitting it into the plastic lens 30. 4 Q fixes the lens frame 20 in the radial direction.

In addition, the molding material for the deformed suction sleeve 40 is as follows:
A1. Actual measurement data using S resin as a specific example will be described later, but as other materials, FA (nylon) and other materials that can satisfy the above conditions were applied, and as shown in the second figure. In the cross-sectional shape of.

Although the fitting part 41 side is formed wide and the fitting part 42 side is narrow, the shape is not limited to such a shape.For example, the cross-sectional shape of the fitting FIIS 41 and the fitting part 42 side A completely reversed cross-sectional shape.

Alternatively, the width of the cross section on the fitting part 41 side is 1lli wider than the width of the fitting part 21 of the lens frame 20! A specific example will be given in which the cross-sectional shape is narrow, and the cross-sectional shape on the fitting part 42 side has approximately the same width as the outer width of the plastic lens 3.0, and the cross-sectional shape is an inverted T-shape. be able to.

Now, when a temperature change is applied to the plastic lens 30 held by the lens holding device constructed as described above, the plastic lens 30 expands and contracts as the temperature changes repeatedly, and thermal stress generated in the radial direction at high temperatures increases. This is absorbed by the elastic deformation of the deformation absorbing sleeve 4o, which has a smaller elastic modulus than the elastic modulus of the molding material of the plastic lens 3o, and can prevent changes in the radius of curvature of the plastic lens 30.

The amount of optical axis misalignment between the plastic lens 3o and the lens frame 2o,
The fitting clearance between the plastic lens and the lens frame in the prior art can be set small because the deformation absorbing sleeve 40 absorbs stress caused by thermal expansion, that is, changes in the radius of curvature.

Furthermore, if a normal clearance is set, it becomes possible to provide a plastic lens system that can be used in a wider temperature range.・Although it has been described that the material for the deformation absorbing sleeve 40 is preferably a material with an elastic modulus smaller than that of the molding material of the plastic lens 30, in order to obtain the above effects, it is necessary to It is only necessary to make the elastic modulus different.

Now, FIG. 3 shows a second actual sleeve example of the present invention, and FIG.
Figure 3 is a front view of the deformed absorbing sleeve, and Figures 3c and d are cross-sectional views and front views of the reverse embodiment of the deformed absorbing sleeve in the same blood case. Some parts are omitted from the illustration.

In the case of the same example, except for the configuration of the deformation absorbing sleeve 40 that is different from the first example 1dμ, everything is the same except that the retaining edge 26 of the presser ring 24 is eliminated, so the modification J1 riIQ,・II ■Sleeve 43, l]
J. The same tips as in the first example will be used and the explanation will be omitted.

The deformed absorbing sleeve 43 is made of hair! −′! 'The outer diameter corresponds to the inner diameter of the fitting part 21 of V20, and 1 of the fitting part 21
A deformed hour projection 45 that fits into the external ring of the plastic lens 30 is intermittently protruded from the inner peripheral surface of the annular fitting 6114 having a width approximately equal to the corner, and the conditions described in the first practical example are applied. 171. '5. It is integrally formed from purple wood.

In addition, as shown in Fig. 3 a, b←, the plastic lens 3
0 is an annular fitting part 47, and a deformation absorbing protrusion 48 corresponding to the deformation absorbing protrusion 45 shown in FIGS. 3a and 3b is provided protruding from the fitting part side of the lens frame 20. Deformation absorbing space IJ-
In addition to the sleeve 46, there are two deformation-absorbing sleeves (not shown) that have ZI deformation-absorbing protrusions protruding from the inner and outer peripheries of the annular sleeve body at the fitting portion of the lens frame 20 and the fitting portion with the plastic lens 30, respectively. This embodiment can be cited as an embodiment similar to the second embodiment shown in FIGS. 3a and 3b.

Therefore, the deformation absorbing sleeve 7'43.4 having the above structure
6 is used to hold the plastic lens 30, the stress of thermal expansion caused by temperature changes in the plastic lens 30 is absorbed by the buckling action of each deformation U and convergence protrusion 45, 48 of the sleeve 43, 46. , a change in the radius of curvature of the plastic lens 30 can be completely prevented.

In other words, the same objective as the first embodiment can be achieved, but in this embodiment, stress caused by thermal expansion of the plastic lens 30 is reduced by the lens frame 20 and g. Since the deformation is absorbed by the buckling action of the deformation absorbing function 43, 46 fitted to the plastic lens 30 side, it is easier to absorb the deformation than when it is absorbed by the elasticity of the annular fitting parts 41, 42, and Even if the material of the deformation-absorbing sleeve has a high elastic modulus, it has the characteristic of being able to exhibit a deformation-absorbing function.

Note that the number, shape, protruding position, etc. of the deformation absorbing protrusions 45, 48 are not limited to the illustrated example.

Next, FIGS. 4a and 4b show a third embodiment of the present invention, and a fourth embodiment of the present invention is shown in FIGS.
Figure a is a side sectional view, and the same figure is a front view of the deformation absorbing sleeve.

The structure of this embodiment other than the deformation absorbing sleeve 49 is completely the same as that of the first practical example, and the same reference numerals are used and the explanation thereof will be omitted.

The deformation absorbing sleeve 49 in this embodiment has an annular fitting part 50 corresponding to the inner diameter of the fitting part 21 of the lens frame 20, and a vertical part of the fitting part 50 on the inner peripheral surface of the fitting part 50. Deformation absorbing protrusions 51 are intermittently protruded from the surface in the direction of IK interaction with the plastic lens 30, and are integrally formed with the same molded material as in the 1st and 2nd embodiments of +111.

Although not shown specifically, an annular fitting portion for the plastic lens 30 is provided, and the lens frame 20 is attached to this.
This is carried out by providing deformation-absorbing protrusions protruding from the fitting portion 21 of the plastic lens 30 and the fitting portion s21 of the lens frame 20, or by protruding deformation-absorbing protrusions from the fitting portion s21 of the plastic lens 30 and the lens frame 20 on the inner and outer peripheral surfaces of the annular sleeve body. In addition, the number, shape, and position of the deformation absorbing protrusions are not limited to the illustrated embodiment, and may be modified by other design changes.

Now, the modified suction 1 [V sleeve 4
When the plastic lens 30 is held in the lens frame 20 with the plastic lens 9 interposed therebetween and a temperature change is applied to the plastic lens 30, the stress generated by the thermal expansion of the plastic lens 30 at high temperatures is absorbed by the bending action of each deformation absorbing protrusion 51. Wk IIV, and can prevent changes in the radius of curvature of the plastic lens 30.

In addition, in the case of this embodiment, it is possible to easily absorb deformation as in the second embodiment, and even if the elastic modulus of the deformation absorbing sleeve is high, it can exhibit the deformation (p) absorbing function, and in particular, each deformation absorbing protrusion Since the bending direction of the plastic lens 51 is constant, the plastic lens 30 is uniformly suppressed by the body attachment part 22, which has the advantage that expansion and contraction of the plastic lens 30 due to temperature changes can be stably obtained.

As is clear from the above description, according to the lens holding device of the present invention, the plastic lens expands in the outer circumferential direction due to thermal expansion due to the elastic deformation of the elastic member interposed between the lens frame and the plastic lens. It can absorb the thermal stress caused by changing the temperature of the plastic lens and prevent the radius of curvature from changing due to temperature changes. It is possible to prevent aberrations from worsening, and if the fitting clearance between the plastic lens and the lens frame is set to the same as before, in other words, the same as when using a glass lens, the normal operating temperature range 1 + F4 (- 20°C ~ +40
Plastic lenses can be put to practical use even at temperatures exceeding 0C.

In addition, within the normal operating temperature range, the plastic 1
It is possible to further reduce the fitting clearance between the lenses and the lens frame, and it is possible to sufficiently meet the demand for reducing the allowable eccentricity of the optical axis between the plastic lens and other lens systems. I can do it.

Furthermore, in the configuration of the lens holding device of the present invention, the modification is simply that an elastic member is newly inserted in addition to the configuration of the conventional lens holding device, and it can be easily configured and can be used as an elastic member. Since the deformation absorbing sleeve is made of synthetic resin, it can be mass-produced by injection molding or the like and can be provided at low cost.

In particular, according to the second aspect of the present invention, the contact area between the plastic lens and/or the lens frame is reduced by each deformation absorbing protrusion protruding from the fitting portion on the plastic lens and the lens frame side. Coupled with the fact that each deformation-absorbing protrusion can be easily deformed into an M-shaped structure, the stress caused by thermal expansion of the plastic lens can be more easily absorbed.1. I can demonstrate this in my own writing.

Moreover, it has the advantage that even if the elastic modulus of the molding material of the two elastic members is high, it can be carried out accurately.

According to the third aspect of the present invention, when the stress caused by thermal expansion of the plastic lens is absorbed by the elastic deformation of the elastic member, the deformation of each deformation 11A5 convergence protrusion is performed by a bending action, so that one bending direction is achieved. Since it can always be regulated in a fixed direction, the Plus Deck lens is pressed against the barrel part of the lens frame. It has the advantage that the direction of suppression can be kept constant and that the expansion and contraction of the plastic lens can be carried out smoothly as the plastic lens changes in degrees.

In addition, Tables ■ and Table ■ below show actual measurement data comparing the amount of change in the radius of curvature due to temperature change of the lens between the lens holding device according to the first practical example of the present invention and the conventional lens holding device. do.

Table ■ shows the data of measuring the radius of curvature of the lens in the normal operating temperature range, and Table Tl shows the data of measuring the change in the radius of curvature of the lens before and after expanding the temperature range. The fitting clearance between the lens and the lens frame was set to 0.03 at room temperature.

[Brief explanation of drawings]

Figure 1a is a side sectional view showing a conventional lens holding device;
The figure is a partial enlarged sectional view of Figure 1a, Figures 1c and cl are explanatory diagrams showing changes in the shape of the lens in Figure 1 &, Figure 1θ is a conventional example different from Figure 1a. Side sectional view shown in Figure 2a
2 is a front view of a deformation-absorbing sleeve; FIG. 3a is a side sectional view showing a second embodiment of the invention; 31:Q b - d are a front view, a side sectional view and a partially omitted front view of the deformation absorbing sleeve; FIG. 4 a is a side sectional view showing the third embodiment of the present invention;
The figure is a front view of the deformation absorbing sleeve. 1.30...Plastic lens 2.20...Mirror frame 3.22@...Lens barrel attachment part 4.21...Lens barrel fitting part 5.23...Mirror frame screw part 6.24・Φ・Holding hole 7.25...Threaded part 26...Press edge 31Φ...Holding edge 40.43, 49...Deformation absorbing sleeve 44.47.
50... Fitting portion 45, 48, 51... Deformation absorbing protrusion Patent applicant Olympus Optical Industry Co., Ltd. Fig. 1 (b) Fig. 1) (d) Fig. 1 (e) 44 (C ) (b) (d) No. 1 (0) 49 (b) et al. 1 Procedural amendment (voluntary) May 28, 1980 Patent application No. 7306 Title of the invention 2 Lens holding device 3, correction Relationship with the case of the person who filed the patent application: 'JJf Shin 2-43-2 M Hatagaya, Shibuya-ku, Tokyo
”K (1) (037) Shigeo Kitamura, President and Director of Olympus Optical Industry Co., Ltd. 4, Agent 6, Number of inventions increased by amendment 7, Subject of supplement (1) Specification, page 7, line 13 [A'B'≧AB
・(1+αt)J is changed to “A'H'-1-AB・(
1-αt)J.

Claims (1)

[Scope of Claims] m. A lens holding device characterized in that it is constructed by interposing an elastic member made of synthetic resin between the inside of the mirror e and the outside of the plastic lens. (2) A patent characterized in that the elastic member is an annular deformation absorbing sleeve having a fitting part with the plastic lens on the inside and a fitting part with the inside of the lens frame on the outside. A lens holding device according to claim 1. (3) Inside the lens frame and outside the plastic lens ff1i [
To. It is constructed by intermittently providing deformation absorbing protrusions on the fitting part with the plastic lens and/or the fitting part with the lens frame, and interposing an elastic member made of synthetic resin as a material. A lens holding device characterized by: (4) Between the inside of the mirror frame and the outside of the plastic lens. Intermittently provide deformation absorbing protrusions with an angular cross-section on the fitting portion with the plastic lens and the fitting portion with the V or the fitting portion with the lens frame.
:)・A lens holding device characterized in that it is constructed by interposing an elastic member made of synthetic resin. (5) The elastic member is provided with an annular fitting portion with the plastic lens or the lens frame, and on the outer periphery or inner periphery of the annular fitting portion. The lens holding device according to claim 3 or 4, characterized in that deformation absorbing protrusions having a cross-sectional creed or 113i bevel shape are provided intermittently.