CN214474203U

CN214474203U - Compact double-field-of-view refrigeration infrared objective lens

Info

Publication number: CN214474203U
Application number: CN202120738888.4U
Authority: CN
Inventors: 张洪升; 贾耘
Original assignee: Kunming Nan Xu Photoelectric Technologies Co ltd
Current assignee: Kunming Nan Xu Photoelectric Technologies Co ltd
Priority date: 2021-04-13
Filing date: 2021-04-13
Publication date: 2021-10-22
Anticipated expiration: 2031-04-13

Abstract

The utility model relates to an infrared optics technical field specifically discloses a two visual field refrigeration infrared objective of compact includes from the object space to the image space in proper order: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; the first lens is a front fixed group, the second lens is a zooming group and a focusing group, the third lens and the fourth lens jointly form a rear fixed group, the fifth lens and the sixth lens jointly form a relay group, and the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially arranged on the same optical axis. The utility model discloses mixed refraction/diffraction face of using has simplified the optical structure form when guaranteeing the image quality, and lens are small in quantity, and whole objective's volume is less, convenient to use operation and range of application more.

Description

Compact double-field-of-view refrigeration infrared objective lens

Technical Field

The utility model relates to an infrared optics technical field, concretely relates to two visual field refrigeration infrared objective of compact.

Background

The uncooled infrared detector has the advantages of low price, small volume, light weight, low power consumption, high reliability and the like, so the uncooled infrared detector is widely applied, and is widely applied to various fields such as monitoring, warning, monitoring, reconnaissance, forest fire prevention and the like due to the all-weather day and night observation capability.

The problems in designing a continuous zoom non-refrigeration infrared objective optical system are that the zoom ratio is generally not large, and the optical length is long, while the traditional continuous zoom refrigeration infrared objective optical system has a complex structure and a large number of lenses, so that the system transmittance is low, the system resolution is low, the total optical length is long, and the overall dimension is large.

The problems in designing a double-view-field uncooled infrared objective optical system are that the zoom ratio is generally not large, and the optical length is long, while the traditional double-view-field refrigerated infrared objective optical system has a complex structure and a large number of lenses, so that the system transmittance is low, the system resolution is low, the total optical length is long, and the overall size is large.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a two visual field refrigeration infrared objective of compact can solve the problem of mentioning among the above-mentioned prior art.

In order to solve the technical problem, the utility model adopts the following technical scheme:

a compact double-field-of-view refrigeration infrared objective sequentially comprises from an object side to an image side: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; the first lens is a front fixed group, the second lens is a zooming group and a focusing group, the third lens and the fourth lens jointly form a rear fixed group, the fifth lens and the sixth lens jointly form a relay group, and the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially arranged on the same optical axis.

Further, the first lens element is a meniscus positive lens element, the object-side surface of the first lens element is convex, the image-side surface of the first lens element is concave, and the diopter is positive.

Further, the second lens is a double-concave negative lens, the object side surface of the second lens is a concave surface, the image side surface of the second lens is a concave surface, and diopter of the second lens is negative.

Further, the third lens is a convex-concave positive lens, the object-side surface of the third lens is a convex surface, the image-side surface of the third lens is a concave surface, and the diopter is positive.

Further, the fourth lens is a concave-convex negative lens, the object-side surface of the fourth lens is a convex surface, the image-side surface of the fourth lens is a concave surface, and diopter of the fourth lens is negative.

Further, the fifth lens is a biconcave negative lens, the object-side surface of the fifth lens is a concave surface, the image-side surface of the fifth lens is a concave surface, and diopter of the fifth lens is negative.

Further, the sixth lens element is a convex-concave positive lens element, the object-side surface of which is convex, the image-side surface of which is concave, and the diopter of which is positive.

Furthermore, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all provided with high-order aspheric surfaces, and a diffraction surface is arranged on the object side surface of the second lens.

Compared with the prior art, the utility model discloses following beneficial effect has:

the diopter of the first lens of the objective lens is positive and is used as a front fixed group; the diopter of the second lens is negative and is used as a zoom group to carry out linear movement to realize zoom, focusing and temperature compensation; the diopter of the third lens is positive, the diopter of the fourth lens is negative, and the third lens and the fourth lens form a rear fixed group; the diopter of the fifth lens is negative, the diopter of the sixth lens is positive, and the fifth lens and the sixth lens form a relay group together. Meanwhile, the refraction/diffraction surface is mixed in the system, so that the system ensures the image quality and simplifies the optical structure form, the number of lenses is small, the volume of the whole objective lens is small, and the use, the operation and the application range are more convenient.

The utility model can realize the phase modulation of the optical wave surface because the diffraction optical element has the characteristics of negative dispersion and negative temperature; and the matching with the refraction element can greatly improve the imaging quality of the system, reduce the volume and weight of the system and reduce the cost. The utility model discloses under the requirement of big zoom ratio, high resolution, can effectively improve the system like matter, shorten the total length of system.

Description of the drawings:

fig. 1 is a schematic view of the optical structure of the present invention in short focus.

Fig. 2 is a schematic view of the optical structure of the present invention in the long focus state.

FIG. 3 is a diagram of the transfer function at 20 ℃ in the short-focus period of the present invention.

FIG. 4 is a graph showing the transfer function at 20 ℃ in the case of long focus of the present invention.

FIG. 5 is a speckle pattern at 20 ℃ in the case of short-focus of the present invention.

FIG. 6 is a speckle pattern at 20 ℃ for the novel coke growth.

FIG. 7 is a diagram of the distortion at 20 ℃ during short scorching of the present invention.

FIG. 8 is a diagram showing the distortion at 20 ℃ in the case of the present invention.

Description of reference numerals: 1-first lens, 2-second lens, 3-third lens, 4-fourth lens, 5-fifth lens, 6-sixth lens.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Examples

A compact double-field-of-view refrigeration infrared objective sequentially comprises from an object side to an image side: a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6; the first lens 1 is a meniscus positive lens, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and diopter of the first lens is positive; the second lens 2 is a biconcave negative lens, the object side surface of the second lens is a concave surface, the image side surface of the second lens is a concave surface, and diopter of the second lens is negative; the third lens 3 is a convex-concave positive lens, the object side surface of the third lens is a convex surface, the image side surface of the third lens is a concave surface, and diopter of the third lens is positive; the fourth lens 4 is a convex-concave negative lens, the object side surface of the fourth lens is a convex surface, the image side surface of the fourth lens is a concave surface, and diopter of the fourth lens is negative; the fifth lens 5 is a biconcave negative lens, the object side surface of the fifth lens is a concave surface, the image side surface of the fifth lens is a concave surface, and diopter of the fifth lens is negative; sixth lens 6 is convex concave positive lens, and its object side is the convex surface, and the image side is the concave surface, and diopter is negative first lens 1 is preceding fixed group, second lens 2 also is focusing group for becoming times group simultaneously, third lens 3 and fourth lens 4 constitute the back jointly and fix the group, fifth lens 5 and sixth lens 6 constitute relay group jointly, first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5 and sixth lens 6 are the optical axis setting altogether in proper order.

The second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5 and the sixth lens 6 are all provided with high-order aspheric surfaces, so that the image quality can be improved, and the influence of temperature change on the image quality can be improved; the object side surface of the second lens 2 is provided with a diffraction surface.

In this embodiment, for a refrigeration infrared detector with 640 × 512 and a pixel size of 15 μm, the focal length f of the optical system is designed as follows: 50mm/250mm, F number: 4.0, field of view: 11.34 ° × 9.08 °/2.24 ° × 1.8 °.

The following table shows aspheric coefficients of the surface S4 of the second lens 2, the surface S5 of the third lens 3, the surface S7 of the fourth lens 4, the surface S9 of the fifth lens 5, and the surface S11 of the sixth lens 6.

TABLE 1 aspheric coefficients of surfaces S3, S6, S7, S9, S11

The aspherical surfaces of the above lenses satisfy the relational expression (the even-order aspherical surface equation is defined as follows):

wherein Z is the distance rise from the vertex of the aspheric surface when the aspheric surface is at the position with the height of y along the optical axis direction; c is 1/R, R represents the paraxial radius of curvature of the mirror surface; k is the cone coefficient; A. b, C, D are high-order aspheric coefficients.

Table 2 lists the diffraction surface coefficients of the second lens 2.

TABLE 2 diffraction surface coefficients for surface S4

Surface of	Diffraction order	Center wavelength (mum)	C1	C2
					S4
	1	4.25	-9.7147E-05	3.6088E-07

Wherein C1 and C2 are respectively the 2-order item and the 4-order item coefficients of the diffraction surface.

This embodiment adopts 5 aspheres, 1 diffraction face just to reach good imaging quality, and the manufacturability is good, can reduce lens quantity, and can reduce cost.

Fig. 3 to 8 are graphs of imaging optical simulation data of the compact dual-field refrigeration infrared objective of the present invention at 20 ℃, where fig. 3 to 4 are graphs of optical transfer function (MTF) curves, the horizontal axis is the logarithm per millimeter (lp/mm), and the vertical axis is the contrast value; fig. 5 to 6 are dot charts, and fig. 7 to 8 are distortion charts. From the graph curves of fig. 3 to 8, it can be seen that the MTF, the root mean square value of the scattered spot and the distortion are all within the standard range at the temperature of 20 ℃, and the system requirements are met.

The embodiment is applied to a refrigeration type infrared detector with the resolution of 640 multiplied by 512 and the pixel size of 15 mu m, and provides a refrigeration infrared objective with large zoom ratio and high resolution, wherein the field of view of the system is 11.34 degrees multiplied by 9.08 degrees/2.24 degrees multiplied by 1.8 degrees, the zoom ratio is 5 times, and good image quality is achieved within the range of minus 40 ℃ to plus 50 ℃.

Reference throughout this specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment described generally in this application. The appearances of the same phrase in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the scope of the invention to effect such feature, structure, or characteristic in connection with other embodiments.

Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention. More specifically, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, other uses will also be apparent to those skilled in the art.

Claims

1. The utility model provides a two visual field refrigeration infrared objective of compact which characterized in that: the device comprises the following components in sequence from an object side to an image side: a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5), and a sixth lens (6); first lens (1) is preceding fixed group, second lens (2) are also focusing group simultaneously for zoom group, third lens (3) and fourth lens (4) constitute the after-fixing group jointly, the relay group is constituteed jointly to fifth lens (5) and sixth lens (6), first lens (1), second lens (2), third lens (3), fourth lens (4), fifth lens (5) and sixth lens (6) are the optical axis setting altogether in proper order.

2. The compact dual field of view refrigerated infrared objective lens of claim 1 wherein: the first lens (1) is a meniscus positive lens, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and diopter of the first lens is positive.

3. The compact dual field of view refrigerated infrared objective lens of claim 1 wherein: the second lens (2) is a double-concave negative lens, the object side surface of the second lens is a concave surface, the image side surface of the second lens is a concave surface, and diopter of the second lens is negative.

4. The compact dual field of view refrigerated infrared objective lens of claim 1 wherein: the third lens (3) is a convex-concave positive lens, the object side surface of the third lens is a convex surface, the image side surface of the third lens is a concave surface, and diopter of the third lens is positive.

5. The compact dual field of view refrigerated infrared objective lens of claim 1 wherein: the fourth lens (4) is a convex-concave negative lens, the object side surface of the fourth lens is a convex surface, the image side surface of the fourth lens is a concave surface, and diopter of the fourth lens is negative.

6. The compact dual field of view refrigerated infrared objective lens of claim 1 wherein: the fifth lens (5) is a biconcave negative lens, the object side surface of the fifth lens is a concave surface, the image side surface of the fifth lens is a concave surface, and diopter of the fifth lens is negative.

7. The compact dual field of view refrigerated infrared objective lens of claim 1 wherein: the sixth lens (6) is a convex-concave positive lens, the object side surface of the sixth lens is a convex surface, the image side surface of the sixth lens is a concave surface, and diopter of the sixth lens is negative.

8. The compact dual field of view refrigerated infrared objective lens of claim 1 wherein: the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) are all provided with high-order aspheric surfaces, and the object side surface of the second lens (2) is provided with a diffraction surface.