CN107678125B

CN107678125B - Industrial monitoring lens adopting free-form surface element

Info

Publication number: CN107678125B
Application number: CN201710824782.4A
Authority: CN
Inventors: 刘红霞; 毕野彪; 张良
Original assignee: Luoyang Institute of Electro Optical Equipment AVIC
Current assignee: Luoyang Institute of Electro Optical Equipment AVIC
Priority date: 2017-09-14
Filing date: 2017-09-14
Publication date: 2020-01-10
Anticipated expiration: 2037-09-14
Also published as: CN107678125A

Abstract

The invention relates to an industrial monitoring lens adopting a free-form surface element, which is an optical system optical path consisting of an objective lens [8], a diaphragm [9], an objective lens [10] and a detector [11] according to the optical path direction. The focal length of the optical system is 11.2mm, and the system adopts a primary imaging mode; the total length of the optical system was 13.3mm, and the weight of the optical system was 1.5 g. F number: 4; distortion in the whole field of view is less than or equal to 3 percent. It is also characterized in that: suitable detectors are 1/3 inches, 1/4 inches CCD or CMOS, suitable wavelength: 0.4-0.7 μm; center wavelength: 0.5 μm. Because the free-form surface optical element is adopted, the number of optical lenses in the optical system is reduced, the weight of the system is greatly reduced, and the light weight is realized. The free-form surface is adopted for eliminating aberration of the optical system, so that the aberration of the optical system is well controlled.

Description

Industrial monitoring lens adopting free-form surface element

Technical Field

The invention belongs to the optical detection technology and relates to an industrial monitoring lens adopting a free-form surface element.

Background

The industrial monitoring lens works in a visible light wave band, images are formed by utilizing different reflection intensities and differences of light reflected by different substances in a scene, and the visual performance of human eyes can be greatly expanded by the industrial lens with different focal lengths.

The industrial lens installed in a special position and place works covertly and reliably, can be used for monitoring the actions of personnel and vehicles and the safety protection of key places, is more and more important to apply, and is rapidly developed and widely applied to military monitoring.

The existing industrial lens is generally designed and manufactured by adopting a conventional optical glass material, the weight and the volume of the lens are heavy, the use requirement of the general industrial field can be met, but the lens cannot be met for airborne application or other special applications with strict requirements on size and weight.

The industrial monitoring lens in the prior art as shown in fig. 1 comprises 5 optical glass lenses, a diaphragm and a detector, and is large in size and heavy in weight.

The free-form surface optical element is a novel optical element, and the optical free-form surface has the characteristics of asymmetric surface shape, flexible spatial layout, rich design freedom degree and the like. The free-form surface is one of the most widely applied curved surface shapes, and can effectively improve the performance of an optical system and simplify the configuration of the optical system. The optical system is applied to an industrial lens, and is very beneficial to the reduction of the size of the optical system and the improvement of the performance of the optical system.

Disclosure of Invention

Technical problem to be solved

In order to avoid the defects of the prior art, the invention provides the industrial monitoring lens adopting the free-form surface element, and the structure of an optical system is simplified and the optical performance is optimized through the design of the free-form surface, so that the miniaturization and the light weight of the industrial monitoring lens are realized while the imaging performance is ensured.

Technical scheme

An industrial monitoring lens adopting a free-form surface element is characterized by comprising a first objective lens 8, a diaphragm 9, a second objective lens 10 and a detector 11; a first objective lens 8, a diaphragm 9, a second objective lens 10 and a detector 11 are arranged along the optical axis of the optical path in sequence; the two mirror surfaces of the first objective lens 8 and the two mirror surfaces of the second objective lens 10 both adopt free-form surfaces, and the free-form surface equation is as follows:

wherein: z (x, y) is the optical surface rise; k is a conic coefficient; c is the radius of curvature; r is the radius height in the optical axis direction; is r is²＝x²+y²；A_iIs a polynomial coefficient; the polynomial coefficients are expanded as:

polynomial term number:

the combination parameters of the first objective lens 8, the diaphragm 9 and the second objective lens 10 are shown in an optical parameter table:

optical parameter table unit: mm is

The optical system formed by the optical parameters has a focal length of 11.2mm, a total length of 13.3mm, a weight of 1.5g, and a F_{Number of}：4。

The first objective lens 8 adopts optical glass SF 4.

The second objective lens 10 adopts optical glass NFK 5.

The detector is 1/3 inches, 1/4 inches CCD or CMOS, and is applicable to the following wavelengths: 0.4-0.7 μm; center wavelength: 0.5 μm.

Advantageous effects

The invention provides an industrial monitoring lens adopting a free-form surface element, which is characterized in that an optical path of an optical system is formed by a first objective lens 8, a diaphragm 9, a second objective lens 10 and a detector 11 according to the direction of the optical path. The focal length of the optical system is 11.2mm, and the system adopts a primary imaging mode; the total length of the optical system was 13.3mm, and the weight of the optical system was 1.5 g. F number: 4; distortion in the whole field of view is less than or equal to 3 percent. It is also characterized in that: suitable detectors are 1/3 inches, 1/4 inches CCD or CMOS, suitable wavelength: 0.4-0.7 μm; center wavelength: 0.5 μm.

The invention has the technical effects that:

1, lightening weight: because the free-form surface optical element is adopted, the number of optical lenses in the optical system is reduced, the weight of the system is greatly reduced, and the light weight is realized.

2, high performance and good imaging quality: the free-form surface is adopted for eliminating aberration of the optical system, so that the aberration of the optical system is well controlled.

Drawings

FIG. 1 is a schematic diagram of a prior art optical path;

1-optical glass brand number: NSK 16; 2-optical glass brand: SF 4; 3, a diaphragm; 4-optical glass brand: SF 4; 5-optical glass brand: NSK 16; 6-optical glass brand: PPK 53; 7-CCD focal plane.

FIG. 2 is a schematic diagram of the optical path of the present invention;

8-optical glass brand: SF 4; 9-a diaphragm; 10-optical glass brand: NFK 5; 11-CCD focal plane.

Detailed Description

The invention will now be further described with reference to the following examples and drawings:

the first objective 8, the diaphragm 9, the second objective 10 and the detector 11 form an optical path of the optical system according to the direction of the optical path.

The incident light is imaged on a detector focal plane 11 through a first objective lens 8, a diaphragm 2 and a second objective lens 10 to form an optical path of the optical system.

The detailed optical parameters are shown in the table below.

Optical parameter table (Unit: mm)

Equation of free-form surface:

wherein: z (x, y) is the optical surface rise; k is a conic coefficient; c is the radius of curvature; r is the height of radius in the direction of the optical axis, and is²＝x²+y²；A_iIs a polynomial coefficient, the polynomial expansion can be written as:

polynomial term number:

Claims

1. An industrial monitoring lens adopting a free-form surface element is characterized by comprising a first objective lens [8], a diaphragm [9], a second objective lens [10] and a detector [11 ]; a first objective lens [8], a diaphragm [9], a second objective lens [10] and a detector [11] are arranged along the optical axis of the optical path in sequence; the two lens surfaces of the first objective lens [8] and the two lens surfaces of the second objective lens [10] both adopt free-form surfaces, and the free-form surface equation is as follows:

polynomial term number:

the combination parameters of the first objective lens [8], the diaphragm [9] and the second objective lens [10] are in an optical parameter table,

optical parameter table unit: mm is

2. The industrial monitoring lens using a free-form surface element according to claim 1, wherein: the first objective lens [8] adopts optical glass SF 4.

3. The industrial monitoring lens using a free-form surface element according to claim 1, wherein: the second objective lens [10] adopts optical glass NFK 5.

4. The industrial monitoring lens using a free-form surface element according to claim 1, wherein: the detector is 1/3 inches, 1/4 inches CCD or CMOS, and is applicable to the following wavelengths: 0.4-0.7 μm; center wavelength: 0.5 μm.