Infrared wide-angle identification optical system

Abstract

The utility model discloses an infrared wide-angle recognition optical system, and belongs to the field of optical lenses, the infrared wide-angle recognition optical system comprises a first lens (L1), a diaphragm (STO), a second lens (L2) and an optical filter (IR) which are sequentially arranged from an object plane to an image plane, the first lens (L1) is a plastic aspheric negative lens, the object side surface of the first lens (L1) is a concave surface, and the image side surface of the first lens (L1) is a concave surface; the second lens (L2) is a plastic aspheric positive lens, the object side surface of which is a convex surface and the image side surface of which is a convex surface. Each lens element satisfies the following relational expression: TTL / f is more than 4.13 and less than 4.416. The infrared wide-angle identification optical system is simple in structure, only comprises two lenses, is small in aperture, is large in field angle, has a good imaging effect, is low in production cost, and has mass production feasibility.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical lenses, and more specifically, relates to an infrared recognition lens. Background Art

[0002] With the rapid development of science and technology, infrared lenses are widely used in various fields such as military, security, medical, and industry. As a result, people have higher and higher requirements for lenses. In order to meet the current market demand, it is necessary to further reduce the size of the lens while increasing the field of view, improving the imaging quality, and reducing the cost. The present invention is made to meet these requirements. Summary of the invention

[0003] The present invention aims to provide an infrared wide-angle recognition optical system with a large viewing angle and a simple structure. The advantages of the system are small aperture, small volume, and a large viewing range. The total length of the entire optical system is less than 3.8 mm, and the viewing angle is greater than 156°. In addition, the present invention only contains two optical lenses, which effectively reduces the production cost. At the same time, the present invention has good imaging quality and can be well adapted to different usage directions.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] An infrared wide-angle recognition optical system comprises four parts from the object plane to the image plane: a first lens (L1), a stop (STO), a second lens (L2), and a filter (IR). The first lens (L1) is a plastic aspheric negative lens, whose object side surface is concave and whose image side surface is concave; the second lens (L2) is a plastic aspheric positive lens, whose object side surface is convex and whose image side surface is convex.

[0006] The above-mentioned infrared wide-angle recognition optical system satisfies the following relationship:

[0007] -1.1 <f1 / f<-0.7;

[0008] 0.7 <f2 / f<1.2;

[0009] Among them, f1 is the effective focal length of the first lens (L1), f2 is the effective focal length of the second lens (L2), and f is the effective focal length of an infrared wide-angle recognition optical system.

[0010] The above-mentioned infrared wide-angle recognition optical system satisfies the following relationship:

[0011] 4.13<TTL / f<4.416;

[0012] Wherein, TTL is the distance on the optical axis from the object side surface (S1) of the first lens (L1) to the imaging surface (S8), and f is the effective focal length of the infrared wide-angle recognition optical system.

[0013] The above-mentioned infrared wide-angle recognition optical system satisfies the following relationship:

[0014] 0.3<D / f<1;

[0015] 0.2<T1 / ∑T<0.26;

[0016] 0.3<T2 / ∑T<0.4

[0017] Wherein, D is the aperture diameter of the infrared wide-angle identification optical system, f is the effective focal length of the infrared wide-angle identification optical system, T1 is the thickness of the first lens (L1) on the optical axis, T2 is the thickness of the second lens (L2) on the optical axis, and ∑T is the total thickness of the first lens (L1), the second lens (L2) and the filter (IR) on the optical axis.

[0018] The above-mentioned infrared wide-angle recognition optical system satisfies the following relationship:

[0019] 2.3<F#<2.6;

[0020] Wherein, F# is the F number of the infrared wide-angle recognition optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the first embodiment of the present invention;

[0022] Figure 2 is a distortion diagram of the first embodiment of the present invention;

[0023] Figure 3 is an astigmatism curve diagram of the first embodiment of the present invention; DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] like Figure 1 As shown in the figure, it is a structural schematic diagram of an infrared wide-angle recognition system proposed by the present invention, which includes four parts from the object plane to the image plane: a first lens (L1), an aperture (STO), a second lens (L2), and a filter (IR). The first lens (L1) is a plastic aspheric negative lens, whose object side surface is concave and whose image side surface is concave; the second lens (L2) is a plastic aspheric positive lens, whose object side surface is convex and whose image side surface is convex.

[0026] The above-mentioned infrared wide-angle recognition optical system satisfies the following relationship:

[0027] -1.1 <f1 / f<-0.7; (1)

[0028] 0.7 <f2 / f<1.2; (2)

[0029] Among them, f1 is the effective focal length of the first lens (L1), f2 is the effective focal length of the second lens (L2), and f is the effective focal length of an infrared wide-angle recognition optical system.

[0030] The present invention is conducive to reducing optical aberrations and lowering its tolerance sensitivity when satisfying the above-mentioned formulas (1) and (2); at the same time, the optical system only includes two optical lenses and the object side surface (S1) and the image side surface (S2) of the first lens (L1) are both concave lens structures, so that the optical structure is compact, effectively reducing the total length of the optical system of an infrared wide-angle recognition optical system, and meeting the miniaturization requirements.

[0031] The above-mentioned infrared wide-angle recognition optical system satisfies the following relationship:

[0032] 4.13<TTL / f<4.416; (3)

[0033] Wherein, TTL is the distance on the optical axis from the object side surface (S1) of the first lens (L1) to the imaging surface (S7), and f is the effective focal length of the infrared wide-angle recognition optical system.

[0034] The present invention can limit a shorter working distance while having a larger field of view when satisfying formula (3).

[0035] The above-mentioned infrared wide-angle recognition optical system satisfies the following relationship:

[0036] 0.3<D / f<1; (4)

[0037] 0.2<T1 / ∑T<0.26; (5)

[0038] 0.3<T2 / ∑T<0.4; (6)

[0039] Wherein, D is the aperture diameter of the infrared wide-angle identification optical system, f is the effective focal length of the infrared wide-angle identification optical system, T1 is the thickness of the first lens (L1) on the optical axis, T2 is the thickness of the second lens (L2) on the optical axis, and ∑T is the total thickness of the first lens (L1), the second lens (L2) and the filter (IR) on the optical axis.

[0040] The aperture diameter of the present invention is relatively small, and when equation (4) is satisfied, the stray light and aberration of the infrared wide-angle recognition optical system are effectively limited; at the same time, when equations (5) and (6) are satisfied, the thickness of the first lens (L1) and the second lens (L2) are moderate and reasonably distributed, which is beneficial to reducing aberrations while also reducing the tolerance sensitivity of the lenses.

[0041] The above-mentioned infrared wide-angle recognition optical system satisfies the following relationship:

[0042] 2.3<F#<2.6;(7);

[0043] Among them, F# is the F number of an infrared wide-angle recognition optical system.

[0044] The present invention can constrain the depth of field, magnification, and resolution, and achieve higher imaging quality while satisfying formula (7).

[0045] Example 1

[0046] As a specific embodiment of the present invention, the parameters of an infrared wide-angle recognition optical system are shown in Table 1 below:

[0047] Table 1 Structural parameters of an infrared wide-angle recognition optical system

[0048]

[0049]

[0050] Table 2 Surface coefficients of aspherical lenses for an infrared wide-angle recognition optical system

[0051]

[0052] It will be easily understood by those skilled in the art that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An infrared wide-angle recognition optical system, comprising four parts from the object plane to the image plane: a first lens (L1), a stop (STO), a second lens (L2), and a filter (IR), wherein the first lens (L1) is a plastic aspheric negative lens, the object side surface of which is concave, and the image side surface is concave; the second lens (L2) is a plastic aspheric positive lens, the object side surface of which is convex, and the image side surface is convex; The infrared wide-angle recognition optical system is characterized in that: The following relations are also satisfied: 2.3＜F#＜2.6； Among them, F# is the F number of an infrared wide-angle recognition optical system.

2. An infrared wide-angle recognition optical system as claimed in claim 1, characterized in that: The following relationship is satisfied: -1.1 <f1 / f<-0.7; 0.7 <f2 / f<1.2; Among them, f1 is the effective focal length of the first lens (L1), f2 is the effective focal length of the second lens (L2), and f is the effective focal length of an infrared wide-angle recognition optical system.

3. The infrared wide-angle recognition optical system according to claim 1, characterized in that: The following relationship is satisfied: 4.13<TTL / f<4.416; Wherein, TTL is the distance on the optical axis from the object side surface (S1) of the first lens (L1) to the imaging surface (S8), and f is the effective focal length of the infrared wide-angle recognition optical system.

4. The infrared wide-angle recognition optical system according to claim 1, characterized in that: The following relationship is satisfied: 0.3<D / f<1; 0.2<T1 / ∑T<0.26; 0.3<T2 / ∑T<0.4; Wherein, D is the aperture diameter of the infrared wide-angle recognition optical system, f is the effective focal length of the infrared wide-angle recognition optical system, T1 is the thickness of the first lens (L1) on the optical axis, T2 is the thickness of the second lens (L2) on the optical axis, and ∑T is the total thickness of the first lens (L1), the second lens (L2) and the filter (IR) on the optical axis.

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