CN112859302A

CN112859302A - Optical system of super-wide-angle door sight glass

Info

Publication number: CN112859302A
Application number: CN202110162682.6A
Authority: CN
Inventors: 徐安成
Original assignee: Changzhou Institute of Technology
Current assignee: Changzhou Institute of Technology
Priority date: 2021-02-05
Filing date: 2021-02-05
Publication date: 2021-05-28

Abstract

The invention discloses an optical system of an ultra-wide angle door sight glass, which comprises: the front side of the concave bowl-shaped negative lens is provided with an outward convex cambered surface, and the rear side of the concave bowl-shaped negative lens is provided with an inward concave cambered surface; the plano-concave symmetrical large-field-of-view lens group is arranged on the rear side of the concave bowl-shaped negative lens and comprises two plano-concave lenses which are symmetrically arranged; the symmetrical positive lens is arranged on the rear side of the front-end negative lens component, and the front side and the rear side of the symmetrical positive lens are provided with symmetrical convex cambered surfaces; the rear side of the symmetrical positive lens is an imaging surface. The invention provides a wider field of view for an observer based on the design principle of an inverted Galileo telescope, and solves the distortion problem by adopting a symmetrical lens design by means of an ultra-wide-angle lens design method; the visual angle reaches 160 degrees, and a larger observation range can be obtained.

Description

Optical system of super-wide-angle door sight glass

Technical Field

The invention relates to an ultra-wide angle lens, which is particularly more suitable for a door sight glass. The field of view reaches 160 degrees, so that the application can be further expanded, and the optical lens can be combined with an imaging device such as 1/3-inch CCD or CMOS to form a television door mirror.

Background

The door sight glass is an optical lens (group) for observing outdoor conditions indoors commonly seen in the market, the traditional lens group only solves the problem that outdoor conditions can be partially seen, the visual field is insufficient, and human eyes need to be close to the sight holes. And the distortion is large, and the method can only be used for human eye observation.

Disclosure of Invention

In order to solve the problems, the invention provides an ultra-wide-angle lens based on the design principle of an inverted Galilean telescope.

In order to achieve the purpose, the invention provides the following technical scheme:

an ultra-wide angle door scope optical system comprising:

the front side of the concave bowl-shaped negative lens is provided with a convex cambered surface, and the rear side of the concave bowl-shaped negative lens is provided with a concave cambered surface;

the plano-concave symmetrical large-field-of-view lens group is arranged on the rear side of the concave bowl-shaped negative lens and comprises two plano-concave lenses which are symmetrically arranged, one side of each plano-concave lens is a plane, the other side of each plano-concave lens is provided with a concave cambered surface, and one side of each plano-concave lens, which is provided with the concave cambered surface, is arranged adjacently opposite to each other;

the symmetrical positive lens is arranged on the rear side of the front-end negative lens component, and the front side and the rear side of the symmetrical positive lens are provided with symmetrical convex cambered surfaces; the rear side of the symmetrical positive lens is an imaging surface.

Furthermore, the whole optical system of the ultra-wide angle door sight glass only adopts a glass material, and the color difference is allowed to exist.

Further, the concave bowl-shaped negative lens is a wide-angle lens, and the focal length is-26 mm < f1< -25 mm.

Further, the plano-concave symmetrical large-field lens group is completely symmetrical and consistent in material, the focal length of the plano-concave lens is-10 mm < f2 ═ f3< -9mm, and the combined focal length is-5 mm < f23< -4 mm.

Further, the focal length of the symmetrical positive lens is 16mm < f4<17 mm.

Further, the imaging surface is directly imaged, or an imaging device is installed, or a relay lens is connected behind the imaging surface.

Furthermore, the whole optical system of the ultra-wide angle door mirror is of a structure similar to an inverted Galilean telescope.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a wider field of view for an observer based on the design principle of an inverted Galileo telescope, and solves the distortion problem by adopting a symmetrical lens design by means of an ultra-wide-angle lens design method; in order to facilitate the observation of human eyes without excessively adjusting the eyes, the imaging size of an image surface is 3.6mm, so that the observation is facilitated; the visual angle reaches 160 degrees, and a larger observation (imaging) range can be obtained. The lens group is made of one material, so that the manufacturing cost is effectively reduced. The ultra-wide-angle symmetric lens can be suitable for a peephole mirror for observation, and has low cost and high imaging quality.

Drawings

FIG. 1 is a schematic view of a wide field of view application of an ultra-wide angle door mirror optical system;

FIG. 2 is a view showing an optical structure of an optical system of an ultra-wide angle door mirror;

FIG. 3 is a wavefront aberration diagram of an ultra-wide angle door mirror optical system;

FIG. 4 is an aberration diagram of the entrance pupil of an optical system of a super-wide-angle door mirror.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The embodiment provides an optical system of an ultra-wide angle door mirror as shown in fig. 1-2, the system comprises a concave bowl-shaped negative lens, a plano-concave symmetrical large-field lens group and a symmetrical positive lens, and the whole optical system of the ultra-wide angle door mirror is of a structure similar to an inverted galilean telescope. Wherein:

concave bowl-shaped negative lens 1: the front side of the concave bowl-shaped negative lens 1 is provided with a convex cambered surface P1, the rear side is provided with a concave cambered surface P2, and the concave bowl-shaped negative lens 1 is used for increasing the visual field. The concave bowl-shaped negative lens 1 is a bowl-shaped concave lens with a large curvature radius, and mainly has the function of increasing the field of view, but brings larger spherical aberration and distortion.

Plano-concave symmetrical large-field lens group: the two plano-concave lenses are arranged on the rear side of the concave bowl-shaped negative lens 1 and comprise two plano-concave lenses which are symmetrically arranged, namely a first plano-concave lens 2 and a second plano-concave lens 3, one sides of the first plano-concave lens 2 and the second plano-concave lens 3 are planes P3 and P6, the other sides of the first plano-concave lens 2 and the second plano-concave lens 3 are provided with concave cambered surfaces P4 and P5, one side faces of the two plano-concave lenses with the concave cambered surfaces are adjacently arranged face to face, and the plano-concave symmetrical large view field lens group. Lenses L2, L3 are a set of perfectly symmetrical and material-identical negative lenses, the main purpose of which is to eliminate distortion;

the concave bowl-shaped negative lens 1 and the plano-concave symmetrical large-view-field lens group jointly form a front-end negative lens component, so that the view field is enlarged.

Symmetric positive lens 4: the symmetrical positive lens 4 is arranged on the rear side of the front end negative lens component, symmetrical convex cambered surfaces P7 and P8 are arranged on the front side and the rear side of the symmetrical positive lens 4, the symmetrical positive lens 4 is used for compressing a field of view, meanwhile, aberrations such as positive spherical aberration generated at the front end are eliminated, and distortion is further eliminated. The symmetric positive lens 4 is a symmetric positive power lens, and compresses light rays to an image plane P9 (aperture stop).

The rear side of the symmetrical positive lens 4 is an imaging plane, P9 is an imaging plane, and the imaging plane is a proper position for observation, and CCD, CMOS or other imaging devices can be placed on the imaging plane, or a relay lens can be connected later, so that other purposes are expanded. The system is a large-field large-aberration system, various aberrations need to be corrected, and distortion caused by a large field of view is particularly corrected. The symmetrical positive lens 4 is mainly used for compressing light rays and adjusting the exit pupil position, and meanwhile, the positive spherical aberration brought by the front negative lens component is corrected to form an image on an image surface.

Fig. 1 is a schematic view of an application scenario of the invention, in which a large field of view is prominently displayed. Fig. 2 is a structural diagram of the optical system of the present invention, in which it is obviously indicated that the system is composed of 4 lenses, and the structural diagram is clearly marked with an observation position (aperture stop, i.e. exit pupil), and the position can be placed with an imaging device such as CCD, CMOS, etc.

In a preferred embodiment of the present invention, the entire optical system of the super-wide-angle door mirror is made of only one glass material, and chromatic aberration is allowed to exist because only one glass material is used.

FIG. 3 is a wavefront aberration diagram of an ultra-wide angle door mirror optical system; fig. 4 is an entrance pupil aberration diagram of the optical system of the super-wide-angle door mirror.

In this embodiment, the parameters of each lens (including the thickness and the pitch of each lens, the refractive index of each lens, the radius of curvature, the focal length F, and the refractive index of each lens material) are preferably: the concave bowl-shaped negative lens 1 is a wide-angle lens, and the focal length is-26 mm < f1< -25 mm; the plano-concave symmetrical large-field lens group is completely symmetrical and consistent in material, the focal length of the first plano-concave lens 2 and the focal length of the second plano-concave lens 3 are-10 mm < f2 ═ f3< -9mm, and the combined focal length is-5 mm < f23< -4 mm; the combined focal length of the concave bowl-shaped negative lens 1, the first plano-concave lens 2 and the second plano-concave lens 3 is-4 mm < f123< -3 mm; the focal length of the symmetrical positive lens 4 is 16mm < f4<17 mm.

The specific parameters of the present embodiment are selected as shown in the following table, wherein Table 1 shows data such as lens data and refractive index of material of the system

TABLE 1

The field angle of the optical system of the ultra-wide angle door sight glass can reach 160 degrees, and further optimization can obtain a larger field of view. The lens designed by the invention is suitable for visible light, and has the wavelength range of 0.48-0.64 micrometer, the main wavelength of 0.55 micrometer, the sub-wavelength of 0.60 micrometer and the sub-wavelength of 0.52 micrometer.

The invention is based on the design concept of local symmetry, which shows that the main structure is symmetrical, and the materials used by the lenses are completely the same. The front negative lens component has symmetrical structure, mainly takes the plano-concave symmetrical design as a main design, solves the problem of large view field, and simultaneously reduces the spherical aberration problem caused by the large view field as much as possible. The arrangement of the diaphragm is superposed with an image plane P9 to form an object space telecentric optical path. The invention relates to a telephoto lens, which takes an inverted Galilean telescope as a design principle, adopts a negative-positive lens separation mode by means of an ultra-wide angle lens design method and belongs to a telephoto lens. The concave bowl-shaped negative lens 1 with negative focal power, the first plano-concave lens 2 and the second plano-concave lens 3 form a front group, the rear group of lenses has positive focal power, and light rays are diffused by the front group, compressed by the rear group and imaged on an image plane P9.

The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.

Claims

1. An optical system of an ultra-wide angle door mirror, comprising:

2. The system of claim 1, wherein the entire system is made of only one glass material, allowing color differences.

3. The ultra-wide angle door mirror optical system according to claim 1, wherein said concave bowl-shaped negative lens is a wide angle lens having a focal length of-26 mm < f1< -25 mm.

4. The ultra-wide angle door mirror optical system according to claim 1, wherein the plano-concave symmetrical large field lens group is completely symmetrical and has uniform material, the focal length of the plano-concave lens is-10 mm < f2 ═ f3< -9mm, and the combined focal length is-5 mm < f23< -4 mm.

5. An ultra-wide angle door speculum optical system as in claim 1, wherein said positive symmetric lens has a focal length of 16mm < f4<17 mm.

6. The ultra-wide angle door endoscope optical system according to the claim 1, characterized in that, the imaging surface is directly imaged, or an imaging device is installed, or a relay lens is connected in series.

7. The system of claim 1, wherein the entire system is configured as an inverted Galilean telescope.