CN104090350A

CN104090350A - Long-wave infrared objective lens

Info

Publication number: CN104090350A
Application number: CN201410379078.9A
Authority: CN
Inventors: 夏冰
Original assignee: JIANGSU KALUOKA INTERNATIONAL CARTOON & COMIC Co Ltd
Current assignee: JIANGSU KALUOKA INTERNATIONAL CARTOON & COMIC Co Ltd
Priority date: 2014-08-04
Filing date: 2014-08-04
Publication date: 2014-10-08

Abstract

The invention relates to a long-wave infrared objective lens which comprises a lens group. The long-wave infrared objective lens is characterized in that the lens group comprises a first lens, a second lens and a third lens, which are coaxially arranged in sequence from object space to image space, wherein the first lens is a concave lens, the second lens and the third lens form a positive lens group, and the concave lens and the positive lens group are separated from each other at certain distances; the convex surfaces of the first lens, the second lens and the third lens are even aspheric surfaces and face towards the object space, and the concave surfaces of the first lens, the second lens and the third lens face towards the image space. The design inherits the advantages of a retrofocus structure, and the long-wave infrared objective lens has the characteristics of simple structure, small size, light weight and uniform illumination of an image surface and has an oversized field of view, so that the long-wave infrared objective lens has wide application prospects.

Description

A kind of LONG WAVE INFRARED object lens

Technical field

The design relates to LONG WAVE INFRARED object lens, belongs to optical technical field.

Background technology

Non-refrigerate infrared focal plane array seeker can at room temperature be worked well, and have that quality is light, volume is little, the life-span is long, cost is low, power consumption is little, startup is fast and the advantage such as good stability, met the military infrared system of civilian infrared system and part to Long Wave Infrared Probe in the urgent need to, be applied widely.But compare with refrigeration type infrared detector, the sensitivity of non-refrigerated infrared detector is obviously not high, thereby to require the relative aperture of optical system be that 1 left and right (being greater than as far as possible 1) makes up this deficiency.Along with the development of scanning technique, electron scanning realizes staring imaging by substituting traditional mechanical scanning completely.The infrared image that obtains large scene requires infrared optical system to have very large visual field.

Reflective and refraction-reflection type structure is unsuitable for large visual field low beam and learns system, this be because: focal length is too short, can not meet the requirement of reflecting element to space in reflective and refraction-reflection type structure, and along with the increase of visual field, central obscuration can increase than also thereupon, causes the emittance utilization factor of system to reduce.

Summary of the invention

For above-mentioned requirements, the design has adopted the anti-long distance structure that can realize super wide-angle.This structure is made up of 2 mirror groups, and front group of close object space is negative lens group, and rear group is positive lens groups, and both at intervals.This structure makes image space master system-oriented mobile below, thereby obtains larger back work distance.The interval of positive negative lens group is larger, and the distance that image space interarea moves is backward just larger, and the back work distance of camera lens also can be longer, meets the demand of ultra-large vision field.

For achieving the above object, the design realizes by following technological means:

A kind of LONG WAVE INFRARED object lens, comprise lens combination, it is characterized in that: described lens combination comprises the first lens, the second lens, the 3rd lens that are coaxially arranged in order from object space to image space; Described first lens is negative lens, and described the second lens, the 3rd lens are positive lens groups, between negative lens and positive lens groups at intervals; Described first lens, the second lens, the 3rd lens convex surface are even this aspheric surface and towards object space, described first lens, the second lens, the 3rd concave lens surface are towards image space.

Preferred:

Described a kind of LONG WAVE INFRARED object lens, is characterized in that: on the second lens convex surface, be also provided with diaphragm.

Described a kind of LONG WAVE INFRARED object lens, is characterized in that: the service band of described lens combination is 8-12 μ m, and effective focal length is 6mm, and relative aperture is 1:0.8.

Described a kind of LONG WAVE INFRARED object lens, is characterized in that: described lens combination is germanium mirror.

Described a kind of LONG WAVE INFRARED object lens, is characterized in that: the back work distance of described lens combination is from being 15mm.

Described a kind of LONG WAVE INFRARED object lens, is characterized in that: described lens combination overall length is 86.13mm.

The invention has the beneficial effects as follows: the advantage of anti-long distance structure has been inherited in this design: simple in structure, volume is little, and quality is light, and illuminance of image plane is even to have again ultra-large vision field, these features make it have wide application prospect simultaneously.

Brief description of the drawings

Fig. 1 is lens combination composition structural representation.

The implication of drawing reference numeral is as follows: 1 first lens, 2 second lens, 3 the 3rd lens, 1-1 first lens convex surface, 1-2 first lens concave surface, 2-1 the second lens convex surface, 2-2 the second concave lens surface, 3-1 the 3rd lens convex surface, 3-2 the 3rd concave lens surface.

Embodiment

Below in conjunction with Figure of description, design is further described.

As shown in Figure 1, a kind of LONG WAVE INFRARED object lens, comprise lens combination, it is characterized in that: described lens combination comprises the first lens 1, the second lens 2, the 3rd lens 3 that are coaxially arranged in order from object space to image space; Described first lens 1 is negative lens, and described the second lens 2, the 3rd lens 3 are positive lens groups, between negative lens and positive lens groups at intervals; Described first lens 1, the second lens 2, the 3rd lens 3 convex surface 1-1,2-1,3-1 are even aspheric surface and towards object space, described first lens, the second lens, the 3rd concave lens surface 1-2,2-2,3-2 are towards image space.

Preferred:

Described a kind of LONG WAVE INFRARED object lens, is characterized in that: on the second lens 2 convex surface 2-2, be also provided with diaphragm.

The design has adopted the anti-long distance structure that can realize super wide-angle.This structure is made up of 2 mirror groups, and front group of close object space is negative lens group, and rear group is positive lens groups, and both at intervals.This structure makes image space master system-oriented mobile below, thereby obtains larger back work distance.The interval of positive negative lens group is larger, and the distance that image space interarea moves is backward just larger, and the back work distance of camera lens also can be longer, meets the demand of ultra-large vision field.

The diaphragm operated by rotary motion of retrofocus type structure, in rear mirror group, makes to diminish by the light inclination angle of rear mirror group, makes it bear less visual field, and corresponding front lens group will be born larger visual field.But, on axle, to put light beam and become divergent beams after by front lens group, the light height that incides rear mirror group increases, and it is large that the aperture that rear mirror group is born becomes.Reversed telephoto lens has the feature that short focal length, large visual field, long back work distance and field angle of image are less than field angle of object, is conducive to the distribution of illuminance of image plane.

System is made up of 3 germanium mirrors, adopts anti-long distance structure, and first lens are negative lens group, and rear 2 lens are positive lens groups.Lens convex surface is even aspheric surface.Diaphragm is placed on the 3rd above, and the 3rd is aspheric surface, can proofread and correct the spherical aberration relevant with aperture.First and one of the aspheric surface of the 6th away from diaphragm, one

Approach image planes, be used for proofreading and correct the off-axis aberration except the curvature of field, as coma, astigmatism.

Along with the progress of aspherical mirror machining technique and optical detection level, aspheric surface is more and more for various optical systems.Aspheric surface not only can be used in optical system that image quality is not high, and at camera, in wide-angle, large aperture, objective with variable focal length, has application.Aspheric use makes optical system structure more simple, and lens thickness attenuation makes object lens of large relative aperture become possibility, or controls a certain senior aberration and improve the image quality of system by aspheric surface.In order to improve system imaging quality simplied system structure, the design has used 3 even aspheric surfaces.

Contrived experiment result shows: the mtf value that is 20 lp/mm places in spatial frequency is greater than 0.7, close to diffraction limit.This system architecture is simple, and visual field is very large, and image quality is better, in military and civilian field, has broad application prospects.

More than show and described the design's ultimate principle, principal character and advantage.The technician of the industry should understand; the design is not restricted to the described embodiments; the principle that the design is just described of describing in above-described embodiment and instructions; do not departing under the prerequisite of the design's spirit and scope; the design also has various changes and modifications, and these changes and improvements all fall within the scope of claimed the design.The claimed scope of the design is defined by appending claims and equivalent thereof.

Claims

1. LONG WAVE INFRARED object lens, comprise lens combination, it is characterized in that: described lens combination comprises the first lens, the second lens, the 3rd lens that are coaxially arranged in order from object space to image space; Described first lens is negative lens, and described the second lens, the 3rd lens are positive lens groups, between negative lens and positive lens groups at intervals; Described first lens, the second lens, the 3rd lens convex surface are even aspheric surface and towards object space, described first lens, the second lens, the 3rd concave lens surface are towards image space.

2. a kind of LONG WAVE INFRARED object lens as claimed in claim 1, is characterized in that: on the second lens convex surface, be also provided with diaphragm.

3. a kind of LONG WAVE INFRARED object lens as claimed in claim 1, is characterized in that: the service band of described lens combination is 8-12 μ m, and effective focal length is 6mm, and relative aperture is 1:0.8.

4. a kind of LONG WAVE INFRARED object lens as claimed in claim 1, is characterized in that: described lens combination is germanium mirror.

5. a kind of LONG WAVE INFRARED object lens as claimed in claim 1, is characterized in that: the back work distance of described lens combination is from being 15mm.

6. a kind of LONG WAVE INFRARED object lens as claimed in claim 1, is characterized in that: described lens combination overall length is 86.13mm.