CN116577922A - Catadioptric magnifier optical system - Google Patents

Abstract

The invention discloses a refraction and reflection type doubling mirror optical system, which adopts a refraction and reflection combined mode to realize optical doubling, and sequentially comprises a first lens, a main reflector, an intermediate mirror group, a secondary reflector and a rear group along an optical path; the magnifying glass optical system is provided with two intermediate image planes which are both positioned in the system. The system can realize the amplification factor of 3-8 times, and is widely applicable to the visible light to infrared wave bands. The whole optical system has the advantages of compact structure, good manufacturability, large multiplying power and the like. Compared with a pure refraction type optical doubling structure form, the invention adopts a refraction and reflection type structure form to carry out optical design, two lenses are arranged in the middle of the optical system to transmit light twice in the optical path, thereby improving the utilization rate of optical elements, effectively reducing the number of lenses, simplifying the optical system, adopting an aspheric surface type for the secondary lens, better correcting the aberration of the off-axis visual field, and having good imaging quality of the design result.

Description

Catadioptric magnifier optical system

Technical Field

The invention relates to a magnifier, in particular to a refraction and reflection type magnifier optical system.

Background

In the military or civil field, the viewing equipment can realize the farther-distance viewing by adding a magnifying glass and adopting an optical magnification method when the requirement of observing the remote target exists. The doubling lens is a telescope in the optical principle, and the common structural forms of the telescope mainly comprise refraction type, reflection type and refraction and reflection type. The traditional telescope is an afocal optical system for receiving parallel light and emitting parallel light, and is designed for human eyes. But the telescope designs which are common today are designed for the detection device, the optical system belongs to the focal system. The optical principle of the doubling lens is the same as that of a telescope without focus.

The patent CN212083799U adopts a pure refraction structural form to design a magnifier adapting to the wide-angle high-power zoom lens, namely the magnifier adapting to the wide-angle high-power zoom lens and the magnifier of the CN 203732794U; similarly, patent CN215769174U, a magnification-increasing mirror for telecentric optical system, also adopts pure refraction mode to design magnification-adjustable magnification-increasing mirror; a night vision optical system of cascading multiple magnifiers is described in patent CN206788457U "night vision device", the magnifier also adopts a purely refractive structure; patent CN113655605a "a magnifier, an optical system and an imaging device" designs a purely refractive magnifier. In summary, the magnifier related to the domestic patent is designed in a pure refraction structure mode.

Refractive telescopes are relatively simple in construction and easy to assemble, but when the magnification is large, their axial dimensions are generally long (for example, patent CN113655605a, which is 280mm long), and large-caliber lenses are many (for example, patent CN 212083799U). The common reflection telescope is mainly used in astronomical telescope to have focus system, its external dimension is large, and there is the problem that the central obscuration is large. Therefore, the multiplication of pure refraction is adopted, when the magnification is larger, the number of lenses is large, and the weight of the system is heavy; the reflective magnifying glass has a very good application because of the problems of large external dimension, large central obscuration and the like.

Disclosure of Invention

Aiming at the common defects of the form of the optical system of the doubling lens, the invention adopts the form of the catadioptric optical system to design the doubling lens, and on the premise of obtaining larger multiplying power, the axial dimension of the optical system is compressed, the gravity center position of the doubling lens is optimized, and the use comfort is improved; the central blocking of the optical system is reduced, the energy collecting effect of the system is ensured, and meanwhile, the imaging quality is good.

The refraction and reflection type doubling mirror optical system sequentially comprises a first lens, a main reflecting mirror, an intermediate mirror group, a secondary reflecting mirror and a rear group along an optical path; the refraction and reflection type magnifying glass optical system is provided with two middle image surfaces, and the image surfaces are all positioned in the system; the catadioptric magnifier optical system can be used for visible light and infrared wave bands.

Further, the first lens is the first optical element of the system, and can be mainly used as a protection window of the system and as a mounting support plate of the intermediate lens group and the secondary reflector.

Further, the main reflector is a first optical element with optical power, the surface shape of the main reflector is a spherical surface, the main reflector is used for converging light rays, and the radius value of the main reflector is as follows: r is more than 70 and less than 120.

Further, the middle lens group has positive focal power, light is transmitted twice in the light path, and the utilization rate of optical elements is improved, so that the number of elements is reduced, and the optical system is simplified.

Further, the secondary reflector is an aspheric surface, the imaging quality of the system edge view field is improved, meanwhile, the surface type aspheric surface degree is low, the processing is easy to realize, and the normalized radius value meets the following conditions: r is more than 15 and less than 35.

Further, the back group is of positive power, and is mainly used for correcting part of residual aberration, and a second intermediate image of the system is imaged at infinity for use by a subsequent optical system.

Further, the blocking ratio in the form of the magnifying glass optical system is defined as the effective aperture phi of the secondary mirror _{Secondary times} Phi with the effective caliber of the main mirror _{Main unit} Is a ratio of phi _{Secondary times} /φ _{Main unit} ≤0.35。

The beneficial effects of the invention are as follows:

the magnification of the invention can reach 3-8 times in the form of the magnifying glass optical system, the whole structure is light and compact, the requirement of optical magnification of the optical system in the military and civil fields can be met, and meanwhile, the invention has good use comfort when the whole gravity center is at the rear in use, and can be widely applied to products for shooting, observation and other purposes.

Drawings

FIG. 1 is a diagram of a 3-fold micro refractive reflective magnifier optical system;

FIG. 2 is a view of a 3-fold micro refractive reflective magnifier optical system at 0℃field of view;

FIG. 3 is a view of a 3-fold micro refractive reflective magnifier optical system in the optical path of 0.7 field;

FIG. 4 is a full field optical path diagram of a 3-fold micro refractive reflective magnifier optical system;

FIG. 5 is a spot diagram of a 3-fold micro refractive reflective magnifier optical system;

FIG. 6 is a diagram of a 5-fold micro refractive reflective magnifier optical system;

FIG. 7 is a view of a 5-fold micro refractive reflective magnifier optical system at 0℃field of view;

FIG. 8 is a view of a 5-fold micro refractive reflective magnifier optical system in the optical path of 0.7 field;

FIG. 9 is a full field optical path diagram of a 5-fold micro refractive reflective magnifier optical system;

FIG. 10 is a point column diagram of a 5-fold micro refractive reflective magnifier optical system;

FIG. 11 is a diagram of an 8-fold micro refractive reflective magnifier optical system;

fig. 12 is a point column diagram of an 8-fold micro refractive reflective magnifier optical system.

Detailed Description

For the purposes of clarity, content, and advantages of the present invention, a detailed description of the embodiments of the present invention will be described in detail below with reference to the drawings and examples.

The design thought of the refraction and reflection type magnifier optical system is slightly different from that of the traditional magnifier, and firstly, the central blocking is reduced as much as possible under the condition of ensuring the multiplying power and the imaging quality, and the energy of the optical system is increased to obtain a better observation effect.

Example 1

As shown in fig. 1, the optical system diagram of embodiment 1 includes, in order from the object side to the destination side along the optical path: a first lens L1, a main mirror M1, a second lens L2, a third lens L3, a sub-mirror M2, a fourth lens L4, and a first cemented lens L5 (cemented fifth and sixth lenses). The effective caliber of the primary mirror is 40, the effective caliber of the secondary mirror is 14, and the blocking ratio is 0.35.

Table 1 shows the optical system parameters of example 1.

Table 13 times micro-refraction reflection type magnifying glass optical system parameter

Example 2

As shown in fig. 6, the optical system diagram of embodiment 2 includes, in order from the object side to the destination side along the optical path: a first lens L1, a main mirror M1, a first cemented lens L2 (cemented second and third lenses), a fourth lens L3, a sub-mirror M2, a fifth lens L4, and a second cemented lens L5 (cemented sixth and seventh lenses). The effective caliber of the primary mirror is 64, the effective caliber of the secondary mirror is 16.1, and the blocking ratio is 0.25.

Table 2 shows the optical system parameters of example 2.

Table 25 times micro-refraction reflection type magnifying glass optical system parameter

Example 3

As shown in fig. 11, the optical system diagram of embodiment 3 includes, in order from the object side to the destination side along the optical path: a first lens L1, a main mirror M1, a first cemented lens L2 (cemented second, third, and fourth lenses), a fifth lens L3, a sub-mirror M2, a sixth lens L4, and a second cemented lens L5 (cemented seventh and eighth lenses). The effective caliber of the primary mirror is 100, the effective caliber of the secondary mirror is 22.1, and the blocking ratio is 0.22.

Table 3 shows the optical system parameters of example 3.

Table 3 8 times micro-refraction reflection type magnifying glass optical system parameter

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present invention, and such modifications and variations should also be regarded as being within the scope of the invention.

Claims (8)

1. A catadioptric fold mirror optical system, characterized by: the optical path comprises a first lens, a main reflecting mirror, an intermediate mirror group, a secondary reflecting mirror and a rear group in sequence; the magnifying glass optical system is provided with two intermediate image planes which are all positioned in the system;

the first lens is a parallel plate;

the main reflector is a sphere, and the radius value of the main reflector meets the following conditions: r is more than 70 and less than 120;

the middle lens group is of positive focal power, and light is transmitted twice in the light path;

the secondary reflector is an aspheric surface, and the normalized radius value of the secondary reflector meets the following conditions: r is more than 15 and less than 35;

the rear group is of positive focal power.

2. The catadioptric fold mirror optical system of claim 1, wherein:

the blocking ratio of the optical system of the magnifying glass is defined as the effective caliber phi of the secondary mirror _{Secondary times} Phi with the effective caliber of the main mirror _{Main unit} Is a ratio of phi _{Secondary times} /φ _{Main unit} ≤0.35。

3. The catadioptric fold mirror optical system of claim 1, wherein:

the magnification of the magnifying glass optical system is 3-8 times.

4. The catadioptric fold mirror optical system of claim 1, wherein:

the magnifying glass optical system is used for visible light and infrared wave bands.

5. The catadioptric magnifier optical system according to any one of claims 1 to 4, wherein:

the first lens serves as a protective window for the system and as a mounting bracket for the intermediate lens group and the secondary mirror.

6. The catadioptric magnifier optical system according to any one of claims 1 to 4, wherein:

the main reflector is used for converging light rays.

7. The catadioptric magnifier optical system according to any one of claims 1 to 4, wherein:

the secondary mirror is used for improving the imaging quality of the system edge view field.

8. The catadioptric magnifier optical system according to any one of claims 1 to 4, wherein:

the back group is used to correct part of the remaining aberrations and to image a second intermediate image of the system at infinity for use with the subsequent optical system.