WO2019095710A1 - Optical imaging system - Google Patents

Abstract

Provided is an optical imaging system, comprising, in order from the object side to the image side along the optical axis: a first lens (E1), a second lens (E2), a third lens (E3), a fourth lens (E4), and a fifth lens (E5). The first lens (E1) has a positive focal power, an object side surface of the first lens (E1) is a convex surface, and an image side surface of said first lens is a concave surface; the second lens has a positive focal power; the third lens has a positive focal power or a negative focal power; the fourth lens has a negative focal power; the total effective focal length f of the optical imaging system and the entrance pupil diameter (EPD) of the optical imaging system satisfy f/EPD≤1.70.

Description

Optical imaging system

Cross-reference to related applications

This application claims the Chinese patent application filed on November 14, 2017 in the Chinese National Intellectual Property Office (SIPO), the patent application number is 201711122644.8, and the patent application number is 201721513474.1 submitted to the SIPO on November 14, 2017. Priority and interest in Chinese patent application, the entire disclosure of which is hereby incorporated by reference.

Technical field

The present application relates to an optical imaging system and, more particularly, to an optical imaging system comprising four lenses.

Background technique

In recent years, with the rapid update of portable electronic products such as mobile phones and tablet computers, the market has increasingly diversified requirements for imaging lenses on portable electronic products. For example, in the field of iris recognition, when the product-side imaging lens is required to be based on infrared band imaging, the lens needs to have characteristics such as a large aperture and high imaging quality to meet imaging needs and improve the lens's adaptability to various imaging environments. .

Summary of the invention

The present application provides an optical imaging system that is adaptable to at least one of the above-discussed shortcomings of the prior art, such as a large aperture lens based on infrared band imaging, that is applicable to portable electronic products.

In one aspect, the present application provides an optical imaging system that includes, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens. Wherein, the first lens may have a positive power, the object side may be a convex surface, the image side may be a concave surface; the second lens may have a positive power; the third lens has a positive power or a negative power; the fourth lens may With negative power; the total effective focal length f of the optical imaging system and the entrance pupil diameter EPD of the optical imaging system can satisfy f/EPD ≤ 1.70.

In one embodiment, the object side of the second lens may be a concave surface, and the image side may be a convex surface.

In one embodiment, the third lens can have a negative power.

In one embodiment, the optical imaging system may further include an infrared band pass filter disposed between the fourth lens and the image side, and the band pass band of the infrared band pass filter may be 750 nm to 950 nm.

In one embodiment, the band pass wavelength band of the infrared band pass filter may be 850 nm to 940 nm.

In one embodiment, the total effective focal length f of the optical imaging system, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens may satisfy 1.0 ≤ |f / f1 | + | f / f2 | ≤ 2.0.

In one embodiment, the radius of curvature R3 of the side surface of the second lens object and the radius of curvature R4 of the side surface of the second lens image may satisfy 1.0≤|R3+R4|/|R3-R4|≤5.0.

In one embodiment, the total effective focal length f of the optical imaging system and the effective focal length f4 of the fourth lens may satisfy -1.0 ≤ f / f4 ≤ 0.

In one embodiment, the distance from the center of the side of the first lens to the distance TTL of the imaging surface of the optical imaging system on the optical axis and the distance between the adjacent lenses of the first lens to the fourth lens on the optical axis ∑ AT can satisfy 3.5 ≤ TTL / ∑ AT ≤ 5.0.

In one embodiment, the dispersion coefficient V2 of the second lens and the dispersion coefficient V3 of the third lens may satisfy |V2-V3|<45.

In one embodiment, the radius of curvature R1 of the side surface of the first lens object and the radius of curvature R2 of the side surface of the second lens image may satisfy 1.0≤|R1+R2|/|R1-R2|≤2.5.

In another aspect, the present application also provides an optical imaging system including, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens. Wherein, the first lens may have a positive power, the object side may be a convex surface, the image side may be a concave surface; the second lens may have a positive power; the third lens has a positive power or a negative power; the fourth lens may Having a negative power; the total effective focal length f of the optical imaging system, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens may satisfy 1.0 ≤ |f / f1 | + | f / f2 | ≤ 2.0.

In still another aspect, the present application also provides an optical imaging system including, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens. Wherein, the first lens may have a positive power, the object side may be a convex surface, and the image side may be a concave surface; the second lens may have a positive power, the object side may be a concave surface, and the image side may be a convex surface; the third lens may be There is a negative power; the fourth lens can have a negative power. The optical imaging system may further include an infrared band pass filter disposed between the fourth lens and the image side, the band pass band of the infrared band pass filter may be 750 nm to 950 nm, and more specifically, the band pass band may be It is from 850 nm to 940 nm.

In still another aspect, the present application also provides an optical imaging system including, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens. Wherein, the first lens may have a positive power, the object side may be a convex surface, and the image side may be a concave surface; the second lens may have a positive power, the object side may be a concave surface, and the image side may be a convex surface; the third lens may be There is a negative power; the fourth lens can have a negative power. The radius of curvature R3 of the side surface of the second lens object and the radius of curvature R4 of the side surface of the second lens image may satisfy 1.0 ≤ |R3 + R4 | / | R3 - R4 | ≤ 5.0.

In still another aspect, the present application also provides an optical imaging system including, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens. Wherein, the first lens may have a positive power, the object side may be a convex surface, and the image side may be a concave surface; the second lens may have a positive power, the object side may be a concave surface, and the image side may be a convex surface; the third lens may be There is a negative power; the fourth lens can have a negative power. The total effective focal length f of the optical imaging system and the effective focal length f4 of the fourth lens may satisfy -1.0 ≤ f / f4 ≤ 0.

In still another aspect, the present application also provides an optical imaging system including, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens. Wherein, the first lens may have a positive power, the object side may be a convex surface, and the image side may be a concave surface; the second lens may have a positive power, the object side may be a concave surface, and the image side may be a convex surface; the third lens may be There is a negative power; the fourth lens can have a negative power. The distance TTL from the center of the side of the first lens to the imaging plane of the optical imaging system on the optical axis and the distance between the adjacent lenses of the first lens to the fourth lens on the optical axis ∑AT can satisfy 3.5≤TTL /∑AT≤5.0.

In still another aspect, the present application also provides an optical imaging system including, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens. Wherein, the first lens may have a positive power, the object side may be a convex surface, and the image side may be a concave surface; the second lens may have a positive power, the object side may be a concave surface, and the image side may be a convex surface; the third lens may be There is a negative power; the fourth lens can have a negative power. The dispersion coefficient V2 of the second lens and the dispersion coefficient V3 of the third lens may satisfy |V2-V3|<45.

In still another aspect, the present application also provides an optical imaging system including, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens. Wherein, the first lens may have a positive power, the object side may be a convex surface, and the image side may be a concave surface; the second lens may have a positive power, the object side may be a concave surface, and the image side may be a convex surface; the third lens may be There is a negative power; the fourth lens can have a negative power. The radius of curvature R1 of the side surface of the first lens object and the radius of curvature R2 of the side surface of the second lens image may satisfy 1.0 ≤ |R1 + R2 | / | R1 - R2 | ≤ 2.5.

The present application employs a plurality of (for example, four) lenses, and the optical imaging system has a small size by appropriately distributing the power, the surface shape, the center thickness of each lens, and the on-axis spacing between the lenses. At least one beneficial effect, such as large aperture, low sensitivity, high image quality, and imaging based on infrared wavelength.

DRAWINGS

Other features, objects, and advantages of the present invention will become more apparent from the description of the appended claims. In the drawing:

1 is a schematic structural view of an optical imaging system according to Embodiment 1 of the present application;

2A to 2D respectively show an axial chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system of Embodiment 1;

3 is a schematic structural view of an optical imaging system according to Embodiment 2 of the present application;

4A to 4D respectively show an axial chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system of Embodiment 2;

FIG. 5 is a schematic structural view of an optical imaging system according to Embodiment 3 of the present application; FIG.

6A to 6D respectively show axial chromatic aberration curves, astigmatism curves, distortion curves, and magnification chromatic aberration curves of the optical imaging system of Embodiment 3.

FIG. 7 is a schematic structural view of an optical imaging system according to Embodiment 4 of the present application;

8A to 8D respectively show an axial chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system of Embodiment 4;

9 is a schematic structural view of an optical imaging system according to Embodiment 5 of the present application;

10A to 10D respectively show an axial chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system of Embodiment 5;

Figure 11 is a block diagram showing the structure of an optical imaging system according to Embodiment 6 of the present application;

12A to 12D respectively show an axial chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system of Embodiment 6;

Figure 13 is a block diagram showing the structure of an optical imaging system according to Embodiment 7 of the present application;

14A to 14D respectively show an axial chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system of Embodiment 7;

Figure 15 is a block diagram showing the structure of an optical imaging system according to Embodiment 8 of the present application;

16A to 16D respectively show an axial chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system of Embodiment 8;

Figure 17 is a block diagram showing the structure of an optical imaging system according to Embodiment 9 of the present application;

18A to 18D respectively show an axial chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system of Embodiment 9;

19 is a schematic structural view of an optical imaging system according to Embodiment 10 of the present application;

20A to 20D respectively show an axial chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve of the optical imaging system of Embodiment 10.

Detailed ways

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is only illustrative of the exemplary embodiments of the present application, and is not intended to limit the scope of the application. Throughout the specification, the same drawing reference numerals refer to the same elements. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in the present specification, the expressions of the first, second, third, etc. are used to distinguish one feature from another, and do not represent any limitation of the feature. Thus, the first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of the lens have been somewhat exaggerated for convenience of explanation. Specifically, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the spherical or aspherical shape shown in the drawings. The drawings are only examples and are not to scale.

As used herein, a paraxial region refers to a region near the optical axis. If the surface of the lens is convex and the position of the convex surface is not defined, it indicates that the surface of the lens is convex at least in the paraxial region; if the surface of the lens is concave and the position of the concave surface is not defined, it indicates that the surface of the lens is at least in the paraxial region. Concave. The surface closest to the object in each lens is referred to as the object side, and the surface of each lens closest to the image plane is referred to as the image side.

It is also to be understood that the terms "comprising", "including", "having", "include","," However, it is not excluded that one or more other features, elements, components, and/or combinations thereof are present. Moreover, when an expression such as "at least one of" appears after the list of listed features, the entire listed features are modified instead of the individual elements in the list. Further, when describing an embodiment of the present application, "may" is used to mean "one or more embodiments of the present application." Also, the term "exemplary" is intended to mean an example or an illustration.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having meaning consistent with their meaning in the context of the related art, and will not be interpreted in an idealized or overly formal sense unless This is clearly defined in this article.

It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings.

The features, principles, and other aspects of the present application are described in detail below.

An optical imaging system according to an exemplary embodiment of the present application may include, for example, four lenses having powers, that is, a first lens, a second lens, a third lens, and a fourth lens. The four lenses are sequentially arranged from the object side to the image side along the optical axis.

In an exemplary embodiment, the first lens may have a positive power, the object side may be a convex surface, the image side may be a concave surface; the second lens may have a positive power; and the third lens has a positive power or a negative power The fourth lens may have a negative power. By arranging both lenses close to the object side (i.e., the first lens and the second lens) as positive lenses having positive power, it is advantageous to increase the aperture of the system and increase the amount of light per unit time.

In an exemplary embodiment, the object side of the second lens may be a concave surface, and the image side may be a convex surface.

In an exemplary embodiment, the third lens may have a negative power, the object side may be a concave surface, and the image side may be a convex surface.

In an exemplary embodiment, the object side of the fourth lens may be a convex surface, and the image side may be a concave surface.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression f/EPD < 1.70, where f is the total effective focal length of the optical imaging system and EPD is the entrance pupil diameter of the optical imaging system. More specifically, f and EPD can further satisfy 1.20 ≤ f / EPD ≤ 1.66. The smaller the aperture number Fno of the optical imaging system (ie, the total effective focal length of the system f/the diameter of the system's entrance pupil EPD), the larger the aperture of the system, and the greater the amount of light entering the same unit time. Reducing the number of apertures Fno can effectively increase the amount of light passing through the system per unit time, so that the system can better meet the shooting requirements in low light environments, and has a large aperture advantage.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 1.0 ≤ |f / f1 | + | f / f2 | ≤ 2.0, where f is the total effective focal length of the optical imaging system, and f1 is the first lens The effective focal length, f2 is the effective focal length of the second lens. More specifically, f, f1 and f2 may further satisfy 1.10 ≤ |f / f1 | + | f / f2 | ≤ 1.60, for example, 1.20 ≤ |f / f1 | + | f / f2 | ≤ 1.56. Reasonable control of the power of the first lens and the second lens is beneficial to increase the aperture, improve the imaging quality of the central region of the system, and reduce the sensitivity of the system.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 1.0≤|R3+R4|/|R3-R4|≤5.0, where R3 is the radius of curvature of the object side of the second lens, and R4 is the first The radius of curvature of the image side of the two lenses. More specifically, R3 and R4 may further satisfy 1.20 ≤ |R3 + R4 | / | R3 - R4 | ≤ 4.80, for example, 1.29 ≤ |R3 + R4 | / | R3 - R4 | ≤ 4.79. Reasonably arranging the radius of curvature of the side surface and the image side of the second lens object is advantageous for balancing the high spherical aberration of the system and reducing the sensitivity of the field of view in the central region of the system.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression -1.0 ≤ f / f4 ≤ 0, where f is the total effective focal length of the optical imaging system and f4 is the effective focal length of the fourth lens. More specifically, f and f4 may further satisfy -0.60 ≤ f / f4 ≤ 0, for example, -0.57 ≤ f / f4 ≤ -0.08. Reasonable configuration of the effective focal length of the fourth lens can effectively correct the astigmatism of the system and at the same time help ensure the matching of the chief ray angle CRA.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 3.5≤TTL/∑AT≤5.0, where TTL is the distance from the center of the side of the first lens to the imaging plane of the optical imaging system on the optical axis, ∑AT is the sum of the separation distances of any two adjacent lenses in the first lens to the fourth lens on the optical axis (in an optical imaging system having four lenses, ∑AT is the first lens and the second lens is on the optical axis The upper separation distance T12, the separation distance T23 of the second lens from the third lens on the optical axis, and the separation distance T34 of the third lens and the fourth lens on the optical axis, that is, ∑AT=T12+T23+T34) . More specifically, the TTL and ∑AT can further satisfy 3.80 ≤ TTL / ∑ AT ≤ 4.80, for example, 3.84 ≤ TTL / ∑ AT ≤ 4.79. Reasonable control of TTL and ∑AT is beneficial to ensure high imaging quality while ensuring the miniaturization characteristics of the imaging system; in addition, satisfying the conditional formula 3.5 ≤ TTL / ∑ AT ≤ 5 is also beneficial to ensure the processing characteristics of the imaging system.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression |V2-V3|<45, where V2 is the dispersion coefficient of the second lens and V3 is the dispersion coefficient of the third lens. More specifically, V2 and V3 may further satisfy 20 ≤ |V2-V3| ≤ 40, for example, |V2-V3|=35.80. Reasonable control of the dispersion coefficients of the second lens and the third lens is beneficial to correct system chromatic aberration and balance aberration, thereby improving the imaging quality of the imaging system.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional formula 1.00≤|R1+R2|/|R1-R2|≤2.50, where R1 is the radius of curvature of the object side of the first lens, and R2 is the first The radius of curvature of the image side of the two lenses. More specifically, R1 and R2 may further satisfy 1.00 ≤ |R1 + R2 | / | R1 - R2 | ≤ 2.15, for example, 1.00 ≤ |R1 + R2 | / | R1 - R2 | ≤ 2.09. Reasonably controlling the radius of curvature of the side surface of the first lens and the side of the image is beneficial to balance the high spherical aberration of the system; at the same time, satisfying the conditional formula 1.00 ≤ |R1+R2|/|R1-R2|≤2.50 is beneficial to ensure the first lens Processing characteristics.

In an exemplary embodiment, the optical imaging system of the present application may include an infrared band pass filter disposed between the fourth lens and the imaging surface, the band pass band of the infrared band pass filter may be from about 750 nm to about Further, the band pass band may be from about 850 nm to about 940 nm. Providing an infrared band pass filter between the fourth lens and the imaging surface enables infrared light to pass through and filter stray light to eliminate signal interference caused by non-infrared light, for example, imaging due to chromatic aberration introduced by non-infrared light. blurry.

Optionally, the optical imaging system described above may further include at least one aperture to enhance the imaging quality of the imaging system. The diaphragm may be disposed at any position as needed, for example, the diaphragm may be disposed between the object side and the first lens.

Optionally, the optical imaging system described above may further comprise a protective glass for protecting the photosensitive elements on the imaging surface.

An optical imaging system in accordance with the above-described embodiments of the present application may employ multiple lenses, such as the four described above. By properly distributing the power of each lens, the surface shape, the center thickness of each lens, and the on-axis spacing between the lenses, the volume of the imaging system can be effectively reduced, the sensitivity of the imaging system can be reduced, and the imaging system can be improved. The processability makes the optical imaging system more advantageous for production processing and can be applied to portable electronic products. At the same time, the optical imaging system configured as described above also has advantageous effects such as large aperture, high imaging quality, imaging based on infrared band, and the like.

In an embodiment of the present application, at least one of the mirror faces of each lens is an aspherical mirror. The aspherical lens is characterized by a continuous change in curvature from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, the aspherical lens has better curvature radius characteristics, and has the advantages of improving distortion and improving astigmatic aberration. With an aspherical lens, the aberrations that occur during imaging can be eliminated as much as possible, improving image quality.

However, those skilled in the art will appreciate that the various results and advantages described in this specification can be obtained without varying the number of lenses that make up the optical imaging system without departing from the technical solutions claimed herein. For example, although four lenses have been described as an example in the embodiment, the optical imaging system is not limited to including four lenses. The optical imaging system can also include other numbers of lenses if desired.

A specific embodiment of an optical imaging system applicable to the above embodiment will be further described below with reference to the accompanying drawings.

Example 1

An optical imaging system according to Embodiment 1 of the present application will be described below with reference to FIGS. 1 through 2D. FIG. 1 is a block diagram showing the structure of an optical imaging system according to Embodiment 1 of the present application.

As shown in FIG. 1, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 of the first lens E1 is aspherical, and the image side surface S2 is a spherical surface.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 of the second lens E2 is an aspherical surface, and the image side surface S4 is a spherical surface.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 of the third lens E3 is an aspherical surface, and the image side surface S6 is a spherical surface.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 1 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 1, in which the unit of curvature radius and thickness are both millimeters (mm).

Table 1

In this embodiment, the face shape x of each aspherical lens can be defined by using, but not limited to, the following aspherical formula:

Where x is the distance of the aspherical surface at height h from the optical axis, and the distance from the aspherical vertex is high; c is the abaxial curvature of the aspherical surface, c=1/R (ie, the paraxial curvature c is the above table) 1 is the reciprocal of the radius of curvature R; k is the conic coefficient (given in Table 1); Ai is the correction coefficient of the a-th order of the aspherical surface. Table 2 below gives the high order coefficient A ₄ , A ₆ , A ₈ , A ₁₀ , A ₁₂ , A ₁₄ and A _{16 which} can be used for each of the aspherical mirrors S1, S3, S5, S7 and S8 in the embodiment 1. .

Face number	A4	A6	A8	A10	A12	A14	A16
S1	-9.9714E-03	2.5451E-02	-3.8312E-02	3.2087E-02	0.0000E+00	0.0000E+00	0.0000E+00
S3	-8.9649E-02	2.2862E-02	-5.0252E-02	6.5788E-02	0.0000E+00	0.0000E+00	0.0000E+00
S5	2.4510E-01	-1.9517E-01	1.2918E-01	-3.4465E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-4.4841E-01	1.6549E-01	-2.3784E-02	-2.2369E-02	2.2751E-02	-5.9650E-03	0.0000E+00
S8	-2.5119E-01	1.4785E-01	-5.9349E-02	1.2624E-02	-8.7691E-04	-7.5706E-05	0.0000E+00

Table 2

Table 3 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 1, the total effective focal length f of the optical imaging system, the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and the imaging surface. The effective pixel area on S11 is half the length of the diagonal ImgH.

F1 (mm)	4.01	f(mm)	2.86
F2 (mm)	4.15	TTL (mm)	3.98
F3 (mm)	-38.81	ImgH(mm)	2.00
F4(mm)	-7.58

table 3

The optical imaging system of Example 1 satisfies:

f/EPD=1.66, where f is the total effective focal length of the optical imaging system and EPD is the entrance pupil diameter of the optical imaging system;

|f/f1|+|f/f2|=1.40, where f is the total effective focal length of the optical imaging system, f1 is the effective focal length of the first lens E1, and f2 is the effective focal length of the second lens E2;

|R3+R4|/|R3-R4|=2.78, where R3 is the radius of curvature of the object side surface S3 of the second lens E2, and R4 is the radius of curvature of the image side surface S4 of the second lens E2;

f/f4=-0.38, where f is the total effective focal length of the optical imaging system and f4 is the effective focal length of the fourth lens E4;

TTL/∑AT=4.49, where TTL is the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and ∑AT is any adjacent two lenses of the first lens E1 to the fourth lens E4. The sum of the separation distances on the optical axis;

|V2-V3|=35.80, where V2 is the dispersion coefficient of the second lens E2, and V3 is the dispersion coefficient of the third lens E3;

|R1+R2|/|R1-R2|=1.91, where R1 is the radius of curvature of the object side surface S1 of the first lens E1, and R2 is the radius of curvature of the image side surface S2 of the first lens E1.

In addition, FIG. 2A shows an axial chromatic aberration curve of the optical imaging system of Embodiment 1, which indicates that light of different wavelengths is deviated from a focus point after the system. 2B shows an astigmatism curve of the optical imaging system of Embodiment 1, which shows meridional field curvature and sagittal image plane curvature. 2C shows a distortion curve of the optical imaging system of Embodiment 1, which represents distortion magnitude values in the case of different viewing angles. 2D shows a magnification chromatic aberration curve of the optical imaging system of Embodiment 1, which indicates the deviation of different image heights on the imaging plane after the light passes through the system. 2A to 2D, the optical imaging system given in Embodiment 1 can achieve good imaging quality.

Example 2

An optical imaging system according to Embodiment 2 of the present application will be described below with reference to FIGS. 3 to 4D. In the present embodiment and the following embodiments, a description similar to Embodiment 1 will be omitted for the sake of brevity. FIG. 3 is a block diagram showing the structure of an optical imaging system according to Embodiment 2 of the present application.

As shown in FIG. 3, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 and the image side surface S2 of the first lens E1 are both aspherical surfaces.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 and the image side surface S4 of the second lens E2 are aspherical surfaces.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 and the image side surface S6 of the third lens E3 are aspherical surfaces.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 4 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 2, in which the unit of curvature radius and thickness are both millimeters (mm). Table 5 shows the high order coefficient which can be used for each aspherical mirror in Embodiment 2, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1. Table 6 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 2, the total effective focal length f of the optical imaging system, the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and the imaging plane. The effective pixel area on S11 is half the length of the diagonal ImgH.

Table 4

Face number	A4	A6	A8	A10	A12	A14	A16
S1	-3.9884E-03	2.6244E-02	-2.4798E-02	1.6800E-02	0.0000E+00	0.0000E+00	0.0000E+00
S2	1.4033E-02	-2.6481E-02	6.2709E-02	-6.3953E-02	0.0000E+00	0.0000E+00	0.0000E+00
S3	-5.6581E-02	2.7688E-02	-5.6208E-02	3.4185E-02	0.0000E+00	0.0000E+00	0.0000E+00
S4	-6.4003E-03	3.5780E-02	-5.2954E-02	2.0270E-02	0.0000E+00	0.0000E+00	0.0000E+00
S5	2.7918E-01	-3.0019E-01	2.2806E-01	-6.4483E-02	0.0000E+00	0.0000E+00	0.0000E+00
S6	7.6831E-02	-9.1411E-02	1.0635E-01	-2.4613E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-5.6540E-01	1.9405E-01	1.6406E-01	-2.0298E-01	9.0768E-02	-1.4928E-02	0.0000E+00
S8	-3.8494E-01	3.3137E-01	-1.8826E-01	6.6650E-02	-1.3588E-02	1.1891E-03	0.0000E+00

table 5

F1 (mm)	3.51	f(mm)	2.84
F2 (mm)	4.32	TTL (mm)	3.98
F3 (mm)	-222.92	ImgH(mm)	2.03
F4(mm)	-5.01

Table 6

4A shows an axial chromatic aberration curve of the optical imaging system of Embodiment 2, which indicates that light of different wavelengths is deviated from a focus point after the system. 4B shows an astigmatism curve of the optical imaging system of Embodiment 2, which shows meridional field curvature and sagittal image plane curvature. 4C shows a distortion curve of the optical imaging system of Embodiment 2, which represents the distortion magnitude value in the case of different viewing angles. 4D shows a magnification chromatic aberration curve of the optical imaging system of Embodiment 2, which shows the deviation of different image heights on the imaging plane after the light passes through the system. 4A to 4D, the optical imaging system given in Embodiment 2 can achieve good imaging quality.

Example 3

An optical imaging system according to Embodiment 3 of the present application is described below with reference to FIGS. 5 through 6D. FIG. 5 is a block diagram showing the structure of an optical imaging system according to Embodiment 3 of the present application.

As shown in FIG. 5, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 and the image side surface S2 of the first lens E1 are both aspherical surfaces.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 and the image side surface S4 of the second lens E2 are aspherical surfaces.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 and the image side surface S6 of the third lens E3 are aspherical surfaces.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 7 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 3, wherein the units of the radius of curvature and the thickness are all in millimeters (mm). Table 8 shows the high order term coefficients which can be used for the respective aspherical mirrors in Embodiment 3, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1. Table 9 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 3, the total effective focal length f of the optical imaging system, the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and the imaging plane. The effective pixel area on S11 is half the length of the diagonal ImgH.

Table 7

Face number	A4	A6	A8	A10	A12	A14	A16
S1	-1.1071E-02	2.4085E-02	-3.7637E-02	3.3897E-02	0.0000E+00	0.0000E+00	0.0000E+00
S2	6.8800E-03	-1.6701E-02	3.4889E-02	1.9751E-02	0.0000E+00	0.0000E+00	0.0000E+00
S3	-7.6908E-02	2.9368E-02	-3.8545E-02	3.5298E-02	0.0000E+00	0.0000E+00	0.0000E+00
S4	-3.4258E-03	1.4299E-02	-1.7501E-02	7.2246E-03	0.0000E+00	0.0000E+00	0.0000E+00
S5	2.5025E-01	-2.2857E-01	1.4509E-01	-3.8017E-02	0.0000E+00	0.0000E+00	0.0000E+00
S6	1.8589E-02	-1.1851E-02	-1.0924E-02	1.2124E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-5.4197E-01	2.2028E-01	-2.4539E-02	-2.9010E-02	2.8169E-02	-7.5338E-03	0.0000E+00
S8	-2.6877E-01	1.7018E-01	-6.6492E-02	1.3629E-02	-9.0648E-04	-1.0684E-04	0.0000E+00

Table 8

F1 (mm)	4.49	f(mm)	2.78
F2 (mm)	2.95	TTL (mm)	3.90
F3 (mm)	-11.57	ImgH(mm)	1.95
F4(mm)	-5.62

Table 9

Fig. 6A shows an axial chromatic aberration curve of the optical imaging system of Embodiment 3, which shows that light of different wavelengths is deviated from the focus point after the system. Fig. 6B shows an astigmatism curve of the optical imaging system of Embodiment 3, which shows meridional field curvature and sagittal image plane curvature. Fig. 6C shows a distortion curve of the optical imaging system of Embodiment 3, which shows distortion magnitude values in the case of different viewing angles. Fig. 6D shows a magnification chromatic aberration curve of the optical imaging system of Embodiment 3, which shows the deviation of the different image heights on the imaging plane after the light passes through the system. 6A to 6D, the optical imaging system given in Embodiment 3 can achieve good imaging quality.

Example 4

An optical imaging system according to Embodiment 4 of the present application is described below with reference to FIGS. 7 through 8D. FIG. 7 is a block diagram showing the structure of an optical imaging system according to Embodiment 4 of the present application.

As shown in FIG. 7, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 and the image side surface S2 of the first lens E1 are both aspherical surfaces.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 and the image side surface S4 of the second lens E2 are aspherical surfaces.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 and the image side surface S6 of the third lens E3 are aspherical surfaces.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 10 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 4, in which the unit of curvature radius and thickness are both millimeters (mm). Table 11 shows the high order coefficient which can be used for each aspherical mirror in Embodiment 4, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1. Table 12 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 4, the total effective focal length f of the optical imaging system, the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and the imaging surface. The effective pixel area on S11 is half the length of the diagonal ImgH.

Table 10

Face number	A4	A6	A8	A10	A12	A14	A16
S1	-1.0160E-02	2.6657E-02	-3.5926E-02	2.6453E-02	0.0000E+00	0.0000E+00	0.0000E+00
S2	4.7386E-03	-1.7700E-02	2.0829E-02	1.3180E-02	0.0000E+00	0.0000E+00	0.0000E+00
S3	-7.9563E-02	2.9263E-02	-3.3653E-02	3.3470E-02	0.0000E+00	0.0000E+00	0.0000E+00
S4	4.6453E-04	1.5378E-02	-2.0268E-02	6.1712E-03	0.0000E+00	0.0000E+00	0.0000E+00
S5	2.6168E-01	-2.3024E-01	1.4383E-01	-3.7590E-02	0.0000E+00	0.0000E+00	0.0000E+00
S6	2.7549E-02	-1.0891E-02	-9.3132E-03	1.4393E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-5.2721E-01	2.2593E-01	-2.3775E-02	-2.8931E-02	2.8318E-02	-7.2030E-03	0.0000E+00
S8	-2.6910E-01	1.7227E-01	-6.7530E-02	1.3870E-02	-8.4522E-04	-1.1170E-04	0.0000E+00

Table 11

F1 (mm)	4.52	f(mm)	2.78
F2 (mm)	3.25	TTL (mm)	3.97
F3 (mm)	-19.82	ImgH(mm)	2.00
F4(mm)	-6.34

Table 12

Figure 8A shows an axial chromatic aberration curve for the optical imaging system of Example 4, which shows that light of different wavelengths deviates from the focus point after the system. Fig. 8B shows an astigmatism curve of the optical imaging system of Embodiment 4, which shows meridional field curvature and sagittal image plane curvature. Fig. 8C shows a distortion curve of the optical imaging system of Embodiment 4, which shows distortion magnitude values in the case of different viewing angles. Fig. 8D shows a magnification chromatic aberration curve of the optical imaging system of Embodiment 4, which shows the deviation of different image heights on the imaging plane after the light passes through the system. 8A to 8D, the optical imaging system given in Embodiment 4 can achieve good imaging quality.

Example 5

An optical imaging system according to Embodiment 5 of the present application is described below with reference to FIGS. 9 to 10D. FIG. 9 is a block diagram showing the structure of an optical imaging system according to Embodiment 5 of the present application.

As shown in FIG. 9, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 and the image side surface S2 of the first lens E1 are both aspherical surfaces.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 and the image side surface S4 of the second lens E2 are aspherical surfaces.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 and the image side surface S6 of the third lens E3 are aspherical surfaces.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 13 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 5, in which the unit of curvature radius and thickness are both millimeters (mm). Table 14 shows the high order coefficient which can be used for each aspherical mirror surface in Embodiment 5, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1. Table 15 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 5, the total effective focal length f of the optical imaging system, the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and the imaging plane. The effective pixel area on S11 is half the length of the diagonal ImgH.

Table 13

Face number	A4	A6	A8	A10	A12	A14	A16
S1	-1.7098E-02	2.0172E-02	-3.6756E-02	2.1283E-02	0.0000E+00	0.0000E+00	0.0000E+00
S2	4.7340E-03	-1.7431E-02	7.4215E-03	2.4012E-02	0.0000E+00	0.0000E+00	0.0000E+00
S3	-8.4732E-02	3.6290E-02	-3.0111E-02	2.7013E-02	0.0000E+00	0.0000E+00	0.0000E+00
S4	1.8245E-02	1.4204E-02	-2.3245E-02	7.0684E-03	0.0000E+00	0.0000E+00	0.0000E+00
S5	2.4676E-01	-2.3019E-01	1.3679E-01	-4.3561E-02	0.0000E+00	0.0000E+00	0.0000E+00
S6	4.7327E-02	-1.7606E-02	-1.0120E-02	1.6059E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-5.0433E-01	2.2199E-01	-2.4803E-02	-2.8808E-02	2.8303E-02	-7.3604E-03	0.0000E+00
S8	-2.7412E-01	1.7835E-01	-7.0958E-02	1.4561E-02	-7.4260E-04	-1.6043E-04	0.0000E+00

Table 14

F1 (mm)	3.81	f(mm)	2.74
F2 (mm)	3.49	TTL (mm)	3.98
F3 (mm)	-29.19	ImgH(mm)	1.95
F4(mm)	-5.48

Table 15

Fig. 10A shows an axial chromatic aberration curve of the optical imaging system of Embodiment 5, which shows that light of different wavelengths is deviated from the focus point after the system. Fig. 10B shows an astigmatism curve of the optical imaging system of Embodiment 5, which shows meridional field curvature and sagittal image plane curvature. Fig. 10C shows a distortion curve of the optical imaging system of Embodiment 5, which shows distortion magnitude values in the case of different viewing angles. Fig. 10D shows a magnification chromatic aberration curve of the optical imaging system of Embodiment 5, which shows the deviation of different image heights on the imaging plane after the light passes through the system. 10A to 10D, the optical imaging system given in Embodiment 5 can achieve good imaging quality.

Example 6

An optical imaging system according to Embodiment 6 of the present application is described below with reference to FIGS. 11 through 12D. Figure 11 is a block diagram showing the structure of an optical imaging system according to Embodiment 6 of the present application.

As shown in FIG. 11, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 and the image side surface S2 of the first lens E1 are aspherical surfaces.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 and the image side surface S4 of the second lens E2 are aspherical surfaces.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 and the image side surface S6 of the third lens E3 are aspherical surfaces.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 16 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 6, wherein the unit of curvature radius and thickness are both millimeters (mm). Table 17 shows the high order coefficient which can be used for each aspherical mirror surface in Embodiment 6, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1. Table 18 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 6, the total effective focal length f of the optical imaging system, the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and the imaging plane. The effective pixel area on S11 is half the length of the diagonal ImgH.

Table 16

Face number	A4	A6	A8	A10	A12	A14	A16
S1	-1.3296E-02	3.0402E-02	-3.2113E-02	1.0541E-02	0.0000E+00	0.0000E+00	0.0000E+00
S2	1.0378E-03	-3.5111E-03	2.0559E-03	-9.2039E-03	0.0000E+00	0.0000E+00	0.0000E+00
S3	-9.5469E-02	2.5907E-02	-4.0006E-02	5.0531E-03	0.0000E+00	0.0000E+00	0.0000E+00
S4	1.4283E-02	8.7627E-03	-2.5468E-02	8.5038E-03	0.0000E+00	0.0000E+00	0.0000E+00
S5	2.6320E-01	-2.3752E-01	1.4282E-01	-4.1073E-02	0.0000E+00	0.0000E+00	0.0000E+00
S6	5.5867E-02	-8.4874E-03	-1.2622E-02	1.5333E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-5.1171E-01	2.2963E-01	-2.4740E-02	-2.9768E-02	2.7843E-02	-7.0100E-03	0.0000E+00
S8	-2.7862E-01	1.8003E-01	-7.1589E-02	1.4495E-02	-7.2810E-04	-1.4606E-04	0.0000E+00

Table 17

F1 (mm)	3.74	f(mm)	2.77
F2 (mm)	3.99	TTL (mm)	3.98
F3 (mm)	-31671.22	ImgH(mm)	1.95
F4(mm)	-5.56

Table 18

Fig. 12A shows an axial chromatic aberration curve of the optical imaging system of Embodiment 6, which indicates that light of different wavelengths is deviated from the focus point after the system. Fig. 12B shows an astigmatism curve of the optical imaging system of Embodiment 6, which shows meridional field curvature and sagittal image plane curvature. Fig. 12C shows a distortion curve of the optical imaging system of Embodiment 6, which shows the distortion magnitude value in the case of different viewing angles. Fig. 12D shows a magnification chromatic aberration curve of the optical imaging system of Embodiment 6, which shows the deviation of different image heights on the imaging plane after the light passes through the system. 12A to 12D, the optical imaging system given in Embodiment 6 can achieve good imaging quality.

Example 7

An optical imaging system according to Embodiment 7 of the present application is described below with reference to FIGS. 13 to 14D. FIG. 13 is a block diagram showing the structure of an optical imaging system according to Embodiment 7 of the present application.

As shown in FIG. 13, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 and the image side surface S2 of the first lens E1 are both aspherical surfaces.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 and the image side surface S4 of the second lens E2 are aspherical surfaces.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 and the image side surface S6 of the third lens E3 are aspherical surfaces.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 19 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 7, in which the unit of curvature radius and thickness are both millimeters (mm). Table 20 shows the high order term coefficients which can be used for the respective aspherical mirrors in Embodiment 7, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1. Table 21 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 7, the total effective focal length f of the optical imaging system, the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and the imaging surface. The effective pixel area on S11 is half the length of the diagonal ImgH.

Table 19

Face number

A4

A6

A8

A11

A12

A14

A16

S1	-1.2836E-02	2.4848E-02	-1.5943E-02	4.1646E-04	0.0000E+00	0.0000E+00	0.0000E+00
S2	-1.5070E-03	-3.5425E-03	1.2947E-02	-2.0452E-02	0.0000E+00	0.0000E+00	0.0000E+00
S3	-9.6849E-02	3.7047E-02	-3.1174E-02	-5.9912E-03	0.0000E+00	0.0000E+00	0.0000E+00
S4	2.6347E-02	2.4342E-03	-2.4158E-02	7.1233E-03	0.0000E+00	0.0000E+00	0.0000E+00
S5	2.8781E-01	-2.4391E-01	1.4958E-01	-4.0447E-02	0.0000E+00	0.0000E+00	0.0000E+00
S6	1.5901E-02	2.6452E-02	-1.4027E-02	1.2091E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-5.2961E-01	2.3037E-01	-2.5161E-02	-3.0811E-02	2.7692E-02	-6.6267E-03	0.0000E+00
S8	-2.9477E-01	1.8447E-01	-7.1511E-02	1.4126E-02	-7.3095E-04	-1.2212E-04	0.0000E+00

Table 20

F1 (mm)	3.79	f(mm)	2.72
F2 (mm)	4.32	TTL (mm)	3.98
F3 (mm)	-63.42	ImgH(mm)	1.95
F4(mm)	-8.78

Table 21

14A shows an axial chromatic aberration curve of the optical imaging system of Embodiment 7, which indicates that light of different wavelengths is deviated from a focus point after the system. Fig. 14B shows an astigmatism curve of the optical imaging system of Embodiment 7, which shows meridional field curvature and sagittal image plane curvature. Fig. 14C shows a distortion curve of the optical imaging system of Embodiment 7, which shows the distortion magnitude value in the case of different viewing angles. Fig. 14D shows a magnification chromatic aberration curve of the optical imaging system of Embodiment 7, which shows the deviation of the different image heights on the imaging plane after the light passes through the system. 14A to 14D, the optical imaging system given in Embodiment 7 can achieve good imaging quality.

Example 8

An optical imaging system according to Embodiment 8 of the present application is described below with reference to FIGS. 15 to 16D. Fig. 15 is a view showing the configuration of an optical imaging system according to Embodiment 8 of the present application.

As shown in FIG. 15, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 and the image side surface S2 of the first lens E1 are both aspherical surfaces.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 and the image side surface S4 of the second lens E2 are aspherical surfaces.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 and the image side surface S6 of the third lens E3 are aspherical surfaces.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 22 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 8, in which the unit of curvature radius and thickness are both millimeters (mm). Table 23 shows the high order term coefficients which can be used for the respective aspherical mirrors in Embodiment 8, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1. Table 24 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 8, the total effective focal length f of the optical imaging system, the distance from the center of the object side S1 of the first lens E1 to the imaging plane S11 on the optical axis, and optical imaging. The imaging image plane S11 has a half of the diagonal length of the effective pixel area ImgH.

Table 22

Face number

A4

A6

A8

A10

A12

A14

A16

S1	-2.3131E-02	-1.1311E-02	7.2892E-03	-4.2240E-02	0.0000E+00	0.0000E+00	0.0000E+00
S2	-5.4913E-02	-6.4214E-02	1.3068E-02	-8.1674E-03	0.0000E+00	0.0000E+00	0.0000E+00
S3	-1.1392E-01	9.0940E-02	2.6915E-03	-2.2219E-02	0.0000E+00	0.0000E+00	0.0000E+00
S4	5.8144E-02	1.8435E-02	-1.4033E-02	-9.8879E-03	0.0000E+00	0.0000E+00	0.0000E+00
S5	3.5327E-01	-2.5896E-01	1.6992E-01	-4.5009E-02	0.0000E+00	0.0000E+00	0.0000E+00
S6	-4.1261E-03	8.4079E-02	-2.0573E-02	1.5122E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-5.0268E-01	2.2921E-01	-3.0583E-02	-3.4870E-02	2.7014E-02	-5.5272E-03	0.0000E+00
S8	-3.3662E-01	2.0591E-01	-7.4841E-02	1.3514E-02	-5.7119E-04	-1.1052E-04	0.0000E+00

Table 23

F1 (mm)	3.52	f(mm)	2.37
F2 (mm)	4.52	TTL (mm)	3.63
F3 (mm)	-361.27	ImgH(mm)	1.95
F4(mm)	-28.79

Table 24

Fig. 16A shows an axial chromatic aberration curve of the optical imaging system of Embodiment 8, which indicates that light of different wavelengths is deviated from the focus point after the system. Fig. 16B shows an astigmatism curve of the optical imaging system of Embodiment 8, which shows meridional field curvature and sagittal image plane curvature. Fig. 16C shows a distortion curve of the optical imaging system of Embodiment 8, which shows distortion magnitude values in the case of different viewing angles. Fig. 16D shows a magnification chromatic aberration curve of the optical imaging system of Example 8, which shows the deviation of the different image heights on the imaging plane after the light passes through the system. 16A to 16D, the optical imaging system given in Embodiment 8 can achieve good imaging quality.

Example 9

An optical imaging system according to Embodiment 9 of the present application is described below with reference to FIGS. 17 to 18D. Figure 17 is a block diagram showing the structure of an optical imaging system according to Embodiment 9 of the present application.

As shown in FIG. 17, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 and the image side surface S2 of the first lens E1 are both aspherical surfaces.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 and the image side surface S4 of the second lens E2 are aspherical surfaces.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 and the image side surface S6 of the third lens E3 are aspherical surfaces.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 25 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 9, in which the unit of curvature radius and thickness are both millimeters (mm). Table 26 shows the high order coefficient which can be used for each aspherical mirror surface in Embodiment 9, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1. Table 27 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 9, the total effective focal length f of the optical imaging system, the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and the imaging plane. The effective pixel area on S11 is half the length of the diagonal ImgH.

Table 25

Face number	A4	A6	A8	A10	A12	A14	A16
S1	-2.2221E-02	-5.1782E-02	6.0697E-02	-7.3917E-02	0.0000E+00	0.0000E+00	0.0000E+00

S2	-8.2697E-02	-6.1885E-02	1.1784E-02	-5.2779E-03	0.0000E+00	0.0000E+00	0.0000E+00
S3	-1.5859E-01	1.5249E-01	1.5423E-02	-3.0886E-02	0.0000E+00	0.0000E+00	0.0000E+00
S4	5.0611E-02	3.6287E-02	1.8259E-04	-1.7915E-02	0.0000E+00	0.0000E+00	0.0000E+00
S5	4.1083E-01	-2.8284E-01	1.4559E-01	-3.1292E-02	0.0000E+00	0.0000E+00	0.0000E+00
S6	4.3675E-02	6.2899E-02	-4.6464E-02	2.4774E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-4.8905E-01	2.1725E-01	-3.2842E-02	-3.4073E-02	2.6630E-02	-5.3582E-03	0.0000E+00
S8	-3.7479E-01	2.3211E-01	-8.3709E-02	1.3609E-02	2.7294E-04	-2.6942E-04	0.0000E+00

Table 26

F1 (mm)	3.63	f(mm)	2.43
F2 (mm)	4.27	TTL (mm)	3.71
F3 (mm)	-63.48	ImgH(mm)	2.00
F4(mm)	-25.42

Table 27

Fig. 18A shows an axial chromatic aberration curve of the optical imaging system of Example 9, which shows that light of different wavelengths is deviated from the focus point after the system. Fig. 18B shows an astigmatism curve of the optical imaging system of Embodiment 9, which shows meridional field curvature and sagittal image plane curvature. Fig. 18C shows a distortion curve of the optical imaging system of Embodiment 9, which shows distortion magnitude values in the case of different viewing angles. Fig. 18D shows a magnification chromatic aberration curve of the optical imaging system of Example 9, which shows the deviation of the different image heights on the imaging plane after the light passes through the system. 18A to 18D, the optical imaging system given in Embodiment 9 can achieve good imaging quality.

Example 10

An optical imaging system according to Embodiment 10 of the present application is described below with reference to FIGS. 19 to 20D. FIG. 19 is a block diagram showing the structure of an optical imaging system according to Embodiment 10 of the present application.

As shown in FIG. 19, an optical imaging system according to an exemplary embodiment of the present application sequentially includes an aperture STO, a first lens E1, a second lens E2, and a third lens E3, along the optical axis from the object side to the image side. Four lenses E4 and an imaging surface S11.

The first lens E1 has a positive refractive power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface, and the object side surface S1 of the first lens E1 is aspherical, and the image side surface S2 is a spherical surface.

The second lens E2 has a positive refractive power, the object side surface S3 is a concave surface, the image side surface S4 is a convex surface, and the object side surface S3 of the second lens E2 is an aspherical surface, and the image side surface S4 is a spherical surface.

The third lens E3 has a negative refractive power, the object side surface S5 is a concave surface, the image side surface S6 is a convex surface, and the object side surface S5 of the third lens E3 is an aspherical surface, and the image side surface S6 is a spherical surface.

The fourth lens E4 has a negative refractive power, the object side surface S7 is a convex surface, the image side surface S8 is a concave surface, and the object side surface S7 and the image side surface S8 of the fourth lens E4 are aspherical surfaces.

Alternatively, the optical imaging system may further include a filter E5 having an object side S9 and an image side S10. The filter E5 may be an infrared band pass filter having a band pass band of from about 750 nm to about 950 nm, and further, a band pass band may be from about 850 nm to about 940 nm. Light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

Table 28 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the optical imaging system of Example 10, in which the unit of curvature radius and thickness are both millimeters (mm). Table 29 shows the high order coefficient which can be used for each aspherical mirror surface in Embodiment 10, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1. Table 30 gives the effective focal lengths f1 to f4 of the lenses in Embodiment 10, the total effective focal length f of the optical imaging system, the distance from the center of the object side surface S1 of the first lens E1 to the imaging plane S11 on the optical axis, and the imaging plane. The effective pixel area on S11 is half the length of the diagonal ImgH.

Table 28

Face number	A4	A6	A8	A10	A12	A14	A16
S1	-1.4467E-02	1.9190E-02	-3.4642E-02	2.5832E-02	0.0000E+00	0.0000E+00	0.0000E+00

S3	-1.0067E-01	3.0442E-02	-5.2897E-02	5.5773E-02	0.0000E+00	0.0000E+00	0.0000E+00
S5	2.0618E-01	-1.3642E-01	8.2309E-02	-2.0502E-02	0.0000E+00	0.0000E+00	0.0000E+00
S7	-3.4483E-01	9.0594E-02	-3.0599E-02	1.1817E-02	-1.8751E-04	0.0000E+00	0.0000E+00
S8	-2.6299E-01	1.5066E-01	-6.1127E-02	1.3694E-02	-1.3322E-03	0.0000E+00	0.0000E+00

Table 29

F1 (mm)	3.79	f(mm)	2.85
F2 (mm)	3.85	TTL (mm)	4.00
F3 (mm)	-12.42	ImgH(mm)	2.00
F4(mm)	-8.60

Table 30

Figure 20A shows an axial chromatic aberration curve for the optical imaging system of Example 10, which shows that light of different wavelengths deviate from the focus point after the system. Fig. 20B shows an astigmatism curve of the optical imaging system of Embodiment 10, which shows meridional field curvature and sagittal image plane curvature. Fig. 20C shows a distortion curve of the optical imaging system of Embodiment 10, which shows distortion magnitude values in the case of different viewing angles. Fig. 20D shows a magnification chromatic aberration curve of the optical imaging system of Embodiment 10, which shows the deviation of different image heights on the imaging plane after the light passes through the system. 20A to 20D, the optical imaging system given in Embodiment 10 can achieve good imaging quality.

In summary, Embodiments 1 to 10 satisfy the relationship shown in Table 31, respectively.

Conditional formula\example	1	2	3	4	5	6	7	8	9	10
f/EPD	1.66	1.66	1.66	1.50	1.50	1.40	1.30	1.20	1.20	1.66
|f/f1|+|f/f2|	1.40	1.46	1.56	1.47	1.50	1.43	1.35	1.20	1.24	1.49
|R3+R4|/|R3-R4|	2.78	2.86	1.29	1.44	2.16	2.53	2.72	4.42	4.79	2.31
f/f4	-0.38	-0.57	-0.49	-0.44	-0.50	-0.50	-0.31	-0.08	-0.10	-0.33
TTL/∑AT	4.49	4.52	3.84	4.03	4.36	4.32	4.46	4.79	4.70	4.59
|V2-V3|	35.80	35.80	35.80	35.80	35.80	35.80	35.80	35.80	35.80	35.80
|R1+R2|/|R1-R2|	1.91	1.52	2.01	2.09	1.28	1.50	1.49	1.06	1.00	1.76

Table 31

The present application also provides an image forming apparatus whose electronic photosensitive element may be a photosensitive coupling element (CCD) or a complementary metal oxide semiconductor element (CMOS). The imaging device may be a stand-alone imaging device such as a digital camera, or an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging system described above.

The above description is only a preferred embodiment of the present application and a description of the principles of the applied technology. It should be understood by those skilled in the art that the scope of the invention referred to in the present application is not limited to the specific combination of the above technical features, and should also be covered by the above technical features without departing from the inventive concept. Other technical solutions formed by any combination of their equivalent features. For example, the above features are combined with the technical features disclosed in the present application, but are not limited to the technical features having similar functions.

Claims (21)

1. The optical imaging system includes, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens, wherein

   The first lens has a positive power, the object side is a convex surface, and the image side is a concave surface;

   The second lens has a positive power;

   The third lens has a positive power or a negative power;

   The fourth lens has a negative power;

   Wherein, the total effective focal length f of the optical imaging system and the entrance pupil diameter EPD of the optical imaging system satisfy f/EPD≤1.70.
2. The optical imaging system according to claim 1, wherein the object side surface of the second lens is a concave surface and the image side surface is a convex surface.
3. The optical imaging system of claim 1 wherein said third lens has a negative power.
4. The optical imaging system according to claim 1, wherein said optical imaging system further comprises an infrared band pass filter disposed between said fourth lens and said image side, said infrared band pass filter The strip pass band is from 750 nm to 950 nm.
5. The optical imaging system according to claim 4, wherein said infrared band pass filter has a band pass band of 850 nm to 940 nm.
6. The optical imaging system according to any one of claims 1 to 5, wherein a total effective focal length f of the optical imaging system, an effective focal length f1 of the first lens, and an effective focal length f2 of the second lens It satisfies 1.0 ≤ |f / f1 | + | f / f2 | ≤ 2.0.
7. The optical imaging system according to any one of claims 1 to 5, wherein a radius of curvature R3 of the side surface of the second lens object and a radius of curvature R4 of the side surface of the second lens image satisfy 1.0 ≤ |R3 + R4 |/|R3-R4|≤5.0.
8. The optical imaging system according to any one of claims 1 to 5, characterized in that the total effective focal length f of the optical imaging system and the effective focal length f4 of the fourth lens satisfy -1.0 ≤ f / f4 ≤ 0.
9. The optical imaging system according to any one of claims 1 to 5, wherein a distance TTL between a center of a side surface of the first lens object to an imaging surface of the optical imaging system on the optical axis and the first The sum of the separation distances ∑AT of a lens to any adjacent one of the fourth lenses on the optical axis satisfies 3.5 ≤ TTL / ∑ AT ≤ 5.0.
10. The optical imaging system according to any one of claims 1 to 5, characterized in that the dispersion coefficient V2 of the second lens and the dispersion coefficient V3 of the third lens satisfy |V2-V3|<45.
11. The optical imaging system according to any one of claims 1 to 5, wherein a radius of curvature R1 of a side surface of the first lens object and a radius of curvature R2 of a side surface of the second lens image satisfy 1.0 ≤ |R1 + R2 |/|R1-R2|≤2.5.
12. The optical imaging system includes, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, and a fourth lens, wherein

    The first lens has a positive power, the object side is a convex surface, and the image side is a concave surface;

    The second lens has a positive power;

    The third lens has a positive power or a negative power;

    The fourth lens has a negative power;

    Wherein, the total effective focal length f of the optical imaging system, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy 1.0≤|f/f1|+|f/f2|≤2.0.
13. The optical imaging system according to claim 12, wherein a radius of curvature R1 of the side surface of the first lens object and a radius of curvature R2 of the side surface of the second lens image satisfy 1.0 ≤ |R1+R2|/|R1-R2 |≤2.5.
14. The optical imaging system according to claim 12, wherein a radius of curvature R3 of the side surface of the second lens object and a radius of curvature R4 of the side surface of the second lens image satisfy 1.0 ≤ |R3+R4|/|R3-R4 |≤5.0.
15. The optical imaging system according to claim 14, wherein the object side surface of the second lens is a concave surface and the image side surface is a convex surface.
16. The optical imaging system according to claim 12, wherein the total effective focal length f of the optical imaging system and the effective focal length f4 of the fourth lens satisfy -1.0 ≤ f / f4 ≤ 0.
17. The optical imaging system according to claim 12, wherein the dispersion coefficient V2 of the second lens and the dispersion coefficient V3 of the third lens satisfy |V2-V3|<45.
18. The optical imaging system according to claim 12, wherein a distance from a center of the side of the first lens to a distance TTL of the imaging surface of the optical imaging system on the optical axis and the first lens to the first The sum of the separation distances 任意AT of any two adjacent lenses in the four lenses on the optical axis satisfies 3.5 ≤ TTL / ∑ AT ≤ 5.0.
19. The optical imaging system according to any one of claims 12 to 17, wherein the optical imaging system further comprises an infrared band pass filter disposed between the fourth lens and the image side, The band pass band of the infrared band pass filter is 750 nm to 950 nm.
20. The optical imaging system according to claim 19, wherein said infrared band pass filter has a band pass band of 850 nm to 940 nm.
21. The optical imaging system according to any one of claims 13 to 17, wherein the total effective focal length f of the optical imaging system and the entrance pupil diameter EPD of the optical imaging system satisfy f/EPD ≤ 1.70.

Images