KR100236646B1 - Ultra-compact afocal zoom optics - Google Patents

Abstract

The present invention includes an objective lens means having an overall positive refractive power, comprising a first lens group having positive refractive power, a second lens group having negative refractive power, and a second lens group having positive refractive power, from the object side, and the objective lens. It comprises a sizing means for establishing an image formed by the means, and an eyepiece means for receiving the light passing through the sizing means, and having a positive refractive power, and is simple by moving the configured lens to perform shifting, It is possible to implement a compact zoom optical system, and the eye relief is extended to about 19mm (mm) in the eyepiece for easier and more convenient correlation, and the objective lens part and the eyepiece part are made of plastic lenses, thereby providing a light and inexpensive effect.

Description

Ultra-compact afocal zoom optics

The present invention relates to an afocal zoom optical system. More specifically, the present invention relates to an objective lens unit comprising a lens having positive, negative, and positive refractive powers from an object side, and using the constituent lens as a plastic lens. It relates to a focal zoom optical system.

In general, afocal optical systems are classified into a virtual image and a real image. The representative type of the virtual image is a Galileo type, and the representative type of the actual image has various kinds according to the erecting prism system used.

First, the Galileo type, which is a representative type of the virtual image, includes the objective lens having positive refractive power and the eyepiece having negative refractive power from the object side.

The Galileo type structure configured as described above causes the eyepiece to match the focal position of the objective lens so that the image is viewed, so that no inverted image occurs. Therefore, the Galileo type can be designed with a relatively simple structure because it does not need to use an upright system, and can be designed with a significantly reduced number of lenses. The Galileo type is widely used for binoculars called binoculars commonly called opera glass or flat folded binoculars that can be seen in a sports stadium, and the price of the binoculars is inexpensive.

However, in the Galileo type, it is difficult to increase the angle of view in terms of construction, and because the clock that makes it easier to see by making it darker than the visible part becomes obscurely white, the boundary is shifted according to the eye movement, so it is difficult to implement excellent performance. .

On the other hand, the real type is composed of an objective lens having a positive refractive power and an eyepiece having a positive refractive power to match the focus of the objective lens and the eyepiece is the same as the virtual image, but the image formed as the objective lens As magnified, the image produced by the objective lens becomes an inverted inverted image.

Therefore, the actual type requires an upright system that straightens upside down. Although it is more complex in construction than Virtual Model, in terms of performance, it has much more freedom to implement. In other words, it is possible to realize high magnification, large angle of view, and large diameter, and the distinction of the clock that looks white in particular, which is the weakest point in the virtual image, is very good to see, and the eye fatigue can be reduced.

However, in the above-described actual type, the image formed as the objective lens is enlarged as the eyepiece, so that the angle of view of the eyepiece may vary depending on the magnification and the clock angle, that is, the angle of view. Correction of magnification chromatic aberration is difficult. In addition, the sizing system using the sizing prism has a long overall length and increases weight. In addition, in order to implement a large diameter, the objective lens diameter should be large, but when the objective lens diameter is increased, the weight of the binoculars naturally increases, making it difficult to reduce the size and weight.

In particular, in the case of a real-type afocal optical system capable of shifting, that is, zooming, the shifting group and the compensation group must be moved to perform the shifting. It becomes complicated.

The patent application for the actual variable-focal afocal zoom optical system is as follows.

Japanese Unexamined Patent Publication No. 5-5840, US Patent USP Patent No. 5,311,355 and US Patent USP Patent No. 5,491,588.

The above inventions have almost the same configuration in which a part of the lens part of the objective composed of three lenses having positive refractive power and a part of the eyepiece part are moved and shifted. Therefore, the outbreaks are shifted as the focal point of the objective and the eyepiece are shifted, so the field frame must also move. In addition, there is a problem that it is difficult to implement a barrel for shifting because the clear clock does not appear during shifting, and its size is too large, making it difficult to reduce the size and weight. In addition, since the eyepiece is shortened due to the high magnification, the eye relief is shortened, so that it is difficult to observe the glasses while wearing the glasses.

Therefore, the present invention is to solve the conventional problems, it is possible to change by moving only a part of the lens of the objective lens portion consisting of a lens having a very small and positive refractive power, a negative refractive power and a lens having a positive refractive power in the actual type. It provides a very small afocal optical system.

1 is a configuration and an optical path diagram of a wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention on a straight optical axis,

2 is a configuration and an optical path diagram of a telephoto end of an ultra-small afocal zoom optical system according to an embodiment of the present invention on a straight optical axis,

3 is a configuration and an optical path diagram of the wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

4 is a configuration and optical path diagram of a realistic representation of the telephoto end of the ultra-small afocal zoom optical system according to an embodiment of the present invention,

5 is a spherical aberration diagram at the wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

6 is an astigmatism diagram at the wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

7 is a distortion aberration diagram at the wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

8 is a spherical aberration diagram in the telephoto end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

9 is an astigmatism diagram at the telephoto end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

10 is a distortion aberration diagram in the telephoto end of the ultra-small afocal zoom optical system according to the embodiment of the present invention.

The present invention as a means for solving the above technical problem

An objective lens means having an overall positive refractive power, comprising a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power from an object side;

Sizing means for establishing an image formed by the objective lens means;

It includes the eyepiece means for receiving the light passing through the sizing means, having a positive refractive power.

With the above-described configuration, a person having ordinary skill in the art to which the present invention pertains will be described in detail with reference to the accompanying drawings.

FIG. 1 is a configuration and an optical path diagram showing a wide-angle end of an ultra-small afocal zoom optical system according to an embodiment of the present invention on a straight optical axis.

As shown in the accompanying FIG. 1, the wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

An objective lens unit 1 having positive refractive power from the object side;

A sizing unit 2 for sizing light passing through the objective lens unit 1;

The eyepiece 3 has positive refractive power and an object side surface is an aspherical surface.

The objective lens unit 1 has a first lens 11 having an aspherical surface and positive refractive power from an object side, and a second lens 12 having an aspheric surface and negative refractive power and an object having positive refractive power from an object side. It consists of three lenses 13, all of the lenses (11, 12, 13) is made of plastic.

The sizing portion 2 is composed of one prism 22, a first mirror 21, and a second mirror 23.

The wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention configured as described above may include the first lens 11 and the second lens 12 of the objective lens unit 1. Is close to the first mirror 21.

2 is a configuration and an optical path diagram of a telephoto end of an ultra-small afocal zoom optical system according to an embodiment of the present invention expressed on a straight optical axis.

As shown in FIG. 2, the telephoto end of the microscopic afocal zoom optical system according to the embodiment of the present invention,

Since the configuration is the same as that shown in FIG. 1, the same reference numerals as in FIG.

However, the first lens 11 and the second lens 12 of the objective lens unit 1 move to the object side by moving away from the first mirror 21 at a distance from the wide-angle end of FIG. 1. Perform

3 is a configuration and an optical path diagram of the wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention.

As shown in FIG. 3, light passing through the first and second lenses 11 and 12 of the objective lens unit 1 is reflected by the first mirror 21 of the sizing unit 2. And the light passing through the prism 22 through the third lens 13 of the objective lens unit 1 is reflected by the second mirror 23 to be the eyepiece 3 Pass).

4 is a configuration and optical path diagram of the telephoto end of the ultra-small afocal zoom optical system according to the embodiment of the present invention.

As shown in FIG. 4, the overall path of light is the same as that of FIG. 3, except that the first lens 11 and the second lens 12 of the objective lens unit 1 are Go to the side and perform a shift.

5 is a spherical aberration diagram at the wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

6 is an astigmatism diagram at the wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

7 is a distortion aberration diagram at the wide-angle end of the ultra-small afocal zoom optical system according to the embodiment of the present invention.

8 is a spherical aberration diagram in the telephoto end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

9 is an astigmatism diagram at the telephoto end of the ultra-small afocal zoom optical system according to the embodiment of the present invention,

10 is a distortion aberration diagram in the telephoto end of the ultra-small afocal zoom optical system according to the embodiment of the present invention.

With reference to the attached Figures 1 to 10 will be described in the ultra-small afocal zoom optical system according to an embodiment of the present invention.

This invention consists of the 1st lens 11, the 2nd lens 12, and the 3rd lens 13, and comprises the objective lens part 1. As shown in FIG. In particular, the objective lens unit 1 includes the first lens 11 having positive refractive power, the second lens 12 having negative refractive power, and the third lens 13 having positive refractive power, It is distinguished from the objective lens unit consisting of three lenses having a conventional positive refractive power. The first lens 11 having the positive refractive power and the second lens having the negative refractive power are simultaneously shifted among the lenses constituting the objective lens unit 1. The first lens 11 is a lens that performs shifting, and the second lens 12 is a lens that performs compensation.

In addition, the first lens 11 and the second lens 12 of the objective lens unit 1 move at the same time to correct for the trial change according to the object distance.

As described above, as the first lens 11 and the second lens 12 move together, an optical path diagram of incident light is well illustrated in FIGS. 1 to 4. As shown in FIGS. 1 to 4, incident light is incident on the objective lens unit 1, passes through the first lens 11 closest to the object side, and the second lens 12. After passing through), it enters the sizing unit 2. Light incident on the sizing unit 2 is incident on the first mirror 21, is reflected and incident on the prism 22, and is reflected by the second mirror 23 and is incident on the eyepiece 3.

The image of light incident on the eyepiece part 3 is an upright image. The eyepiece portion 3 is composed of one lens having positive refractive power, and enlarges the image formed by the objective lens.

The present invention having the above configuration has a telephoto type of which the overall length is shortened, that is, the main point of the optical system is in front of the front surface of the lens. Configuration is possible.

According to the present invention, the chromatic aberration of the objective lens unit 1 is corrected by increasing the dispersion value of the second lens 12 of the objective lens unit 1, and the first lens 11 and the second lens 12 are corrected. Aspherical surface is employed, that is, the first lens 11 has an aspherical surface, and the second lens 12 has an aspherical surface, so that distortion and spherical aberration are corrected. In addition, by placing the third lens 13 in the eye-side direction of the second lens 12, the direction of the light beam directed from the objective lens unit 1 to the eyepiece 3 as a whole is lowered, so that the outer diameter of the eyepiece 3 is reduced. Prevents it from growing. If the outer diameter of the eyepiece 3 is prevented from increasing as described above, miniaturization is possible.

In addition, the present invention allows the lens 11, 12, 13 and the eyepiece 3 constituting the objective lens unit 1 to be made of plastic lenses so that small size and light weight can be achieved.

The aspherical lens constituting the afocal zoom optical system of the present invention which operates as described above may be expressed by the following equation.

[Equation]

Z = distance from lens vertex to optical axis

Y = distance perpendicular to the optical axis

C = inverse of the lens radius of curvature

K = Conic Constant

A ₄ , A ₆ , A ₈ , A ₈ ,: Aspheric coefficient

The first embodiment of the ultra-small afocal zoom optical system of the present invention, which satisfies the above equation, is shown in Table 1 below.

In Table 1, the angle of view is 8.12 ° to 4.24 °, zooming magnification is 2.25 ~ 4.44, the surface marked '＊' represents the aspherical surface, r is the radius of curvature of the refractive surface, d is the thickness of the lens and the distance between the lenses, nd is the d-line refractive index of the lens, v is the Abbe's number of the lens.

In the above, A and B are the zoom intervals at the time of shift, and the A and B values according to the shift are shown in Table 2 below.

The aspheric coefficients of the second, third, and eleventh pages with '＊' are shown in Table 3 below.

The second embodiment of the ultra-small afocal zoom optical system of the present invention, which satisfies the above equation, is shown in Table 4 below.

In Table 4, the angle of view is 8.12 ° to 4.24 °, the zoom factor is 2.25 to 4.44, the surface marked '*' represents the aspherical surface, r is the radius of curvature of the refractive surface, d is the thickness of the lens and the distance between the lenses. The distance, nd, is the d-line refractive index of the lens, and v is the Abbe's number of the lens.

In the above, A and B are the zoom intervals at the time of shift, and the A and B values according to the shift are shown in Table 5 below.

And. The aspheric coefficients of pages 2, 3, and 11 with “＊” are shown in Table 3 below.

The present invention consists of an objective lens unit consisting of a first lens having positive refractive power, a second lens having negative refractive power, and a third lens having positive refractive power from the object side, and moving the configured lens to perform shifting, thereby making it simple and compact. It is possible to implement the in-zoom optical system, and the eye relief is extended to about 19mm (mm) in the eyepiece for easier and more convenient image observation, and the objective lens part and the eyepiece part are composed of plastic lenses, thereby having a light and inexpensive effect.

Claims (5)

An objective lens means having an overall positive refractive power, comprising a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power from an object side; Sizing means for establishing an image formed by the objective lens means; And an eyepiece means having positive refractive power and receiving light passing through the sizing means, and shifting the first lens group and the second lens group to perform shifting. The said objective lens means and said eyepiece lens means comprise each lens group which comprises the said objective lens means, ie, the 1st lens group, the 2nd lens group, the 3rd lens group, and the said eyepiece means. The ultra-small afocal zoom optical system characterized by the number of lenses to say one. The microscopic afocal zoom optical system according to claim 1, wherein the objective lens means comprises at least one aspherical surface in each of the first lens group and the second lens group. The microscopic afocal zoom optical system according to claim 1, wherein the objective lens means and the eyepiece means comprise plastic lenses. The method of claim 1, wherein the sizing means comprises: one mirror positioned between the second lens group and the third lens group of the objective lens; and one located between the third lens and the eyepiece means of the objective lens. Ultra-small afocal zoom optical system characterized by consisting of a hawk prism and a mirror.

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