JPS62195614A - Plastic lens body structure - Google Patents

Abstract

PURPOSE:To easily produce and assemble plastic lenses without remarkably losing lens functions due to the change of temperature and humidity by forming at least two connection passages along the optical axis of the plastic lenses on the flange parts of the lenses. CONSTITUTION:Two connection passages 10 parallel with the optical axis of the plastic lenses are penetrated into respective flanges 2a-4a of the plastic lenses 2-4 and a connection rod 11 having a large diameter head part 11a is inserted into each of the connection passages 10. Respective lenses 2-4 are pressed into contact with each other and held by the spring force of a spring 12. When the lenses 2-4 are expanded by temperature, the spring 12 is depressed by the displacement of the lenses 2-4 due to the expansion and stress is generated on respective surfaces of the lenses 2-4, so that the lens functions can be prevented from being lossed. When the lenses 2-4 are contracted by temperature, displacement due to the contraction of the lenses 2-4 is absorbed by the spring force of the spring 12. In addition, expansion/ contraction due to humidity change can be similarly absorbed.

Description

Detailed Description of the Invention (,) Technical Field The present invention relates to a plastic lens structure, and more specifically, the present invention relates to a plastic lens structure, and more specifically, a plurality of plastic lenses each having a flange portion formed at the periphery, the flange portions of which are brought into contact with each other. This relates to a plastic lens structure formed by connecting two parts.

(b) Prior Art Recently, instead of using glass lenses to form lenses such as photographic lenses and finder eyepiece lenses, lenses made of plastic materials have come into wide use.

This is because plastic lenses are easy to manufacture.
This is also due to the fact that not only spherical surfaces but also aspherical surfaces, which are difficult to form with glass lenses, can be formed easily and at extremely low cost on the lens surface.

However, plastic lenses have a considerably larger dimensional change due to changes in temperature and humidity than conventional glass lenses, which causes various problems.

That is, the conventional plastic lens structure, as shown in FIG.
At each peripheral part of the plastic lens 2°3.4 (
The respective flange portions 2a and 3a formed on the outer periphery)
, 4a are accommodated.

A front end positioning part IC for regulating the position of the frontmost lens 2 is provided on one end side of the inner circumference of the lens frame 1, and a female screw part 1b is provided on the rear end side. A ring nut-shaped retaining ring 5 is attached to the female threaded portion 1b at the front end positioning portion 1c.
By screwing the lens 2.3.4 in the direction shown in FIG. 1, the lens 2.3.4 is housed and held in the lens frame 1 in a state where it is sandwiched between the front end presta-style fixing portion IC and the holding ring 5 and pressed against each other.

Therefore, when the above-mentioned lens frame 1 is made of metal such as aluminum, the plastic lenses 2, 3.4 have a higher coefficient of linear expansion than aluminum due to the rise in temperature, so the plastic lenses 2, 3. 3.4 expands to a greater extent, stress is applied to the plastic lenses 2 and 3.4, and the lens surface changes, causing distortion in image formation and significantly reducing image resolution.

On the other hand, if both of them contract due to a drop in temperature, the respective flange portions 2a, 3 of the lenses 2, 3.4
A play occurs between the joint portion of 4a, 4a, and the lens frame 1, and as a result, the lens falls, resulting in the same problem as described above.

In addition, the flange portions 2a, 3 of the plastic lenses 2, 3.4 are bonded using adhesive for bonding conventional glass lenses.
Although it is possible to prevent the above-mentioned problems by joining the abutting parts of a and 4a,
This method cannot be adopted because the lens surfaces of the plastic lenses 2, 3.4 are easily attacked by the adhesive, and the lens function is impaired.

(c) Purpose The present invention was made in view of the above-mentioned circumstances, and its purpose is to provide a plastic lens structure that does not significantly impair the lens function even when temperature and humidity change and is easy to manufacture and assemble. It is in.

(d) Structure In order to achieve the above-mentioned object, the present invention provides a plastic lens structure in which a plurality of plastic lenses each having a flange portion formed at the peripheral portion are connected by bringing the flange portions into contact with each other. , a flange portion of the plastic lens is provided with at least two communicating passages in a direction along the optical axis of the lens, and connecting means for displacing in the axial direction according to expansion and contraction of the plastic lens is inserted into each of the communicating passages. The invention is characterized in that the plurality of plastic lenses are integrally connected by the connecting means.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 16.

FIG. 1 is a longitudinal sectional view showing the structure of a first embodiment of the present invention.

In FIG. 1, two communication passages 10.10 parallel to the lens optical axis 0 are bored in each of the flange parts 2a, 3a, 4a of the plastic lenses 2, 3.4, and these communication passages l0910. A connecting rod 11 as a connecting means having a large-diameter head 11a formed at one end is inserted into each of the connecting rods, and the other end of the connecting rod 11 protrudes outward from the outermost plastic lens 4. There is. A coil spring 12 is inserted into this protruding part, and an E-ring 13 is fitted into the groove on the outside of the coil spring 12.
The ring 13 prevents the connecting rod 11 and coil spring 12 from falling off.

And each of the plastic lenses 2, 3.4 is
They are held in pressure contact by the spring force of the coil spring 12.

Therefore, when the plastic lenses 2, 3.4 expand due to temperature, the coil spring 12 is suppressed by the displacement caused by the expansion.

This prevents stress from occurring on each lens surface of the plastic lenses 2, 3.4, which would impair the lens function.

On the other hand, when the plastic lenses 2, 3.4 contract due to temperature, the displacement due to the contraction of the lenses 2, 3.4 is absorbed by the spring force of the coil spring 12.

In addition, the absorbing action is performed in the same manner as described above for expansion and contraction due to changes in humidity.

2 and 3 are a vertical sectional view and a partial perspective view showing the structure of a second embodiment of the present invention.

In the second embodiment, instead of the coil spring 12, E
The belt-shaped leaf spring 14 is fitted into and engaged with a groove 11b formed at the tip of the connecting rod 11, and can have the same function as the first embodiment described above. In the case of this second embodiment, since the coil spring 12 and E-ring 13 of the first embodiment can be replaced by one leaf spring 14, it is possible to save one member and reduce the number of assembly steps.

FIG. 4 is a longitudinal sectional view showing the structure of a third embodiment of the present invention.

In this embodiment, plastic lenses 2 and 3 shown in FIG.
．． 4, each flange portion 2a.

3a, a concentric positioning step 2e on the outside of 4a,
3c, 3d, and 4c are formed, and these are fitted into each other. With this configuration, it becomes easy to stack the plurality of plastic lenses 2, 3.4, and centering adjustment work becomes unnecessary.

FIG. 5 is a longitudinal cross-sectional view showing the configuration of a fourth embodiment of the present invention. This is an example using an elastic body 15 such as rubber.

FIG. 6 is a longitudinal sectional view showing the configuration of a fifth embodiment of the present invention.

In the figure, 2 and 3 are plastic lenses as compound lenses, and 4 is a single plastic lens. In the case of this example, the difference from each of the above-mentioned examples is as follows.
The connecting rod 11 not only connects single lenses, but also connects single lenses together.
The point is that they are cemented together to form a compound lens. this .

In the case of this embodiment, since the plastic lenses can be joined without adhesive, there is no fear that the plastic lenses will be attacked by the adhesive, and the range of practical use can be expanded.

FIG. 7 shows the connecting rod 1 used in each of the above-mentioned embodiments.
FIG. 8 is a side view showing an enlarged version of one embodiment of the first embodiment, and FIG. 8 is a longitudinal sectional view showing a modification thereof.

The connecting rod 11 shown in FIG. 7 is made of metal or plastic, and as described above, a large diameter head Lla is formed at one end (the left end in the figure), and the other end is formed with a large diameter head Lla. A circumferential groove portion ttb is formed, and the intermediate portion 11c is formed to have a uniform thickness, and its outer diameter is smaller than the inner diameter of the communicating path 10 of the plastic lens by a predetermined dimension, that is, the temperature of the plastic lens is expansion due to change,
The size is made small enough to absorb shrinkage.

In the embodiment shown in FIG. 8, the intermediate portion 11c of the connecting rod 11 made of metal or plastic is coated with an elastic body 16 such as raw rubber or urethane rubber. Deformation around the flange portion of the plastic lens can be absorbed by the elastic body 16. Note that when the connecting rod 11 is made of plastic, one elastic body 16 is not necessarily required, but compared to when it is made of metal.

Since the elastic body 16 is inferior in strength, it is also effective to cover the elastic body 16 from the viewpoint of reinforcing the strength.

9 and 10 are a longitudinal sectional view and a front view, respectively, showing the configuration of a sixth embodiment of the present invention.

In the same figure, each flange portion 2a, 3a, 4a of the plastic lens 2.3°4 is connected to a communication path 10 having the same diameter in a direction substantially along the optical axis 0, similar to the embodiment shown in FIG. .10 is formed in two places. In the case of this embodiment, the communicating paths 1o of each plastic lens 2, 3.4 are stacked one on top of the other.
By filling the inside with a filler 20 as a connecting means, such as a highly elastic adhesive such as a rubber adhesive or a resin material having a coefficient of linear expansion equivalent to that of the plastic lens 2-s4, the three The plastic lenses 2 to 4 are integrally connected.

Therefore, in this sixth embodiment as well, as in the above-mentioned embodiments, the plastic lens 2 to
Even if the lens 4 undergoes displacement in the optical axis direction, radial direction, etc. due to expansion or contraction, the displacement can be absorbed by the filling 20, so that the lens function will not be impaired.

A modified embodiment in which a plurality of plastic lenses are connected by filling the communication path 10 with the filler 20 will be described below.

A seventh embodiment of the present invention shown in FIG.
In addition to a communicating path 10 extending along the optical axis direction, a relief hole 10a extending from the communicating path 10 in the radial direction to the lens side circumferential surface is formed in the lens a. With this configuration, the filling 20 also expands in the radial direction, so that the connection force between each plastic lens 2, 3.4 can be strengthened.

In the eighth embodiment of the present invention shown in FIG. 12, a communicating passage 10 is formed in the flange portion 3a of the plastic lens 3 located in the middle, but the communicating path 10 is formed in the flange portion 3a of the plastic lens 3 located in the middle. A communication path 10 is formed in each flange portion 2a, 4a to the middle part in the lens thickness direction, and a relief hole 1 is formed from this middle part in the radial direction toward the lens side circumferential surface.
0b is formed. With this configuration, the inter-lens engagement force is greater than that of the sixth embodiment shown in FIG. 9 and smaller than that of the seventh embodiment shown in FIG. 11.

A ninth embodiment of the present invention shown in FIG.
In addition to forming a communication path 10 in the direction along the optical axis, each flange portion 2a, 3a.

A concave groove LOc having a predetermined depth and having a diameter larger than the inner diameter of the communication passage 10 is formed in the lens thickness direction from the end surface side of the lens 4a. In this way, each flange portion 2a, 3a,
By increasing the adhesion area of 4a, the filling 2
The lens engagement force (connection force) due to zero can be strengthened.

In addition to the sixth embodiment shown in FIG. 9, the tenth embodiment of the present invention shown in FIG.
and 3a, 3a and 4a are formed with concentric positioning step portions 2b and 3b, 3c and 4b having the same dimensions in the radial direction, respectively. With this configuration, it becomes easy to stack the plurality of plastic lenses 2, 3.4, and centering adjustment work becomes unnecessary.

As in the eleventh embodiment shown in FIG. 15, concentric engaged portions 2a, 3a and engaging portions having concave and convex cross sections are formed in corresponding portions of adjacent flange portions 2a, 3a, 4a. By forming 3f and 4f respectively, the same effect as in the tenth embodiment can be obtained.

The twelfth embodiment shown in FIG. 16 consists of two single lenses 2.
The present invention is applied to a cemented lens in which both lens surfaces of No. 3 are brought into close contact with each other.
, 3a, a communication path 10 along the optical axis direction is formed to the middle part in the lens thickness direction, and a relief hole tab is formed from this communication path 10 to the lens side surface in the lens radial direction, and these communication paths 10 and The escape hole 10b is filled with a filler 20, and the same effects as in the above-mentioned embodiment can be obtained. (6) Effects As detailed above, according to the present invention, at least two communicating passages are provided in the flange portion of the plastic lens along the optical axis of the lens, and in each of the communicating passages, expansion of the plastic lens, Since the plurality of plastic lenses are integrally connected by inserting a connecting means that displaces in the axial direction according to contraction, the plastic lenses do not expand or contract due to changes in temperature or humidity. Displacement is easily absorbed, and distortion and rattling of plastic lenses can be effectively prevented from occurring, as well as eliminating the need for separate parts such as a lens frame and a retaining ring, which were previously essential. It is possible to reduce costs.

Furthermore, since the connecting means has an m''Ji4 configuration, it is possible to provide a plastic lens structure that is convenient for automating lens assembly.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of a first embodiment of the present invention, and FIG. FIG. 4 is a longitudinal sectional view showing the configuration of a third embodiment of the present invention, and FIG. 5 is a perspective view showing the structure of the third embodiment. FIG. 6 is a vertical cross-sectional view showing the configuration of the fourth embodiment of the present invention. FIG. 7 is a vertical cross-sectional view showing the configuration of the fifth embodiment of the present invention. FIG. FIG. 8 is a longitudinal cross-sectional view showing a modification thereof, and FIGS. 9 and 10 are the configuration of a sixth embodiment of the present invention. A vertical cross-sectional view and a front view respectively showing. FIG. 11 is a vertical cross-sectional view showing the configuration of a seventh embodiment of the present invention, FIG. 12 is a vertical cross-sectional view showing the configuration of an eighth embodiment of the present invention, and FIG. FIG. 14 is a vertical cross-sectional view showing the structure of the ninth embodiment of the present invention, FIG. 15 is a longitudinal cross-sectional view showing the structure of the tenth embodiment of the present invention, and FIG. The longitudinal cross-sectional view shown in FIG.
FIG. 17 is a longitudinal sectional view showing the structure of a conventional plastic structure. 2.3,4...Plastic lens. 2a, 3a, 4a...flange part, 2b
, 2c, 3b, 3c, 3d, 4b
, 4c...Positioning stepped portion. 2e, 3e...Engaged parts. 3f, 4f...Engagement portion. 10...Communication path. 10a, 10b...Escape holes. 10c...Concave groove, 11...Connecting rod. 12...Coil spring, 13...E
Ring, 14... Leaf spring, 15...
...Elastic body. 20...Filling. Patent applicant Rico Co., Ltd. Part 1 Figure 2 Figure 2alal14a Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 11c 16 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 * Figure 17

Claims (1)

[Claims] (1) In a plastic lens structure formed by connecting a plurality of plastic lenses each having a flange formed on the periphery with the flanges abutting each other, the flange of the plastic lens has a direction along the optical axis of the lens. At least two or more communicating passages are provided, and connecting means for displacing in the axial direction according to expansion and contraction of the plastic lens is inserted into each of the communicating passages, and the plurality of plastic lenses are integrally connected by the connecting means. A plastic lens structure characterized by having a connected structure.