A large aperture, large target surface, long focus optical lens and imaging method thereof

Abstract

The present invention relates to a large aperture, large target surface, long focus optical lens and an imaging method thereof, comprising a first lens, a second lens, a stop, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence from left to right along the incident light path of light; without considering the backcurvature caused by the aspheric coefficient, the first lens is a double concave negative lens, the second lens is a double convex positive lens, the third lens is a meniscus positive lens, the fourth lens is a double convex positive lens, the fifth lens is a double concave negative lens, the sixth lens is a double convex positive lens, and the seventh lens is a meniscus negative lens; wherein the fifth lens and the sixth lens are a cemented lens group. The lens can solve the problems of small imaging target surface and poor light transmission performance while meeting the requirements of high resolution and long focal length.

Description

Technical Field

[0001] The invention relates to a large aperture, large target surface, long focus optical lens and an imaging method thereof. Background Art

[0002] With the continuous development of the security and automotive fields, people's requirements for the imaging quality of optical lenses are constantly increasing, and the types and characteristics of optical lenses are gradually diversified, such as long-focus and short-focus lenses, surround-view lenses, etc. Among them, telephoto lenses are used to image distant objects, and their characteristics are small field of view, small relative aperture, large imaging, etc. At present, the market demand for telephoto lenses is constantly increasing, but the telephoto lenses on the market still have shortcomings, such as small imaging target surface, poor light transmission performance, and poor imaging quality. Summary of the invention

[0003] The object of the present invention is to provide a large aperture, large target surface, long focus optical lens and an imaging method thereof, which can solve the problems of small imaging target surface and poor light transmission performance while meeting the requirements of high resolution and long focal length.

[0004] The technical solution of the present invention is: a large aperture large target surface telephoto optical lens, comprising a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence from left to right along the incident light path of the light; without considering the backcurvature caused by the aspheric coefficient, the first lens is a double concave negative lens, the second lens is a double convex positive lens, the third lens is a meniscus positive lens, the fourth lens is a double convex positive lens, the fifth lens is a double concave negative lens, the sixth lens is a double convex positive lens, and the seventh lens is a meniscus negative lens; wherein the fifth lens and the sixth lens are a cemented lens group.

[0005] Furthermore, the first lens to the seventh lens are all made of glass material.

[0006] Furthermore, the first lens, the second lens, the fifth lens and the sixth lens are glass spherical lenses, and the third lens, the fourth lens and the seventh lens are glass aspherical lenses.

[0007] Furthermore, the focal length of the optical system of the lens is , the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are respectively , , , , , , ,in , , , , , , and Meet the following ratio: -2.5< / <-0.5, 0.5< / <2.5, 3.5< / <5.5, 0.5< / <2.5, -2.5< / <-0.5, 0.5< / <2.5, -2.5< / <-0.5.

[0008] Furthermore, the first lens satisfies the relationship: ≥1.5, ≥50.0; the second lens satisfies the relationship: ≤1.5, ≥50.0; the third lens satisfies the relationship: ≥1.5, ≥50.0; the fourth lens satisfies the relationship: ≥1.5, ≤50.0; the fifth lens satisfies the relationship: ≥1.5, ≤50.0; the sixth lens satisfies the relationship: ≥1.5, ≥50.0; The seventh lens satisfies the relationship: ≥1.5, ≤50.0; where is the refractive index, is the Abbe constant.

[0009] Furthermore, the total optical length TTL of the optical system of the lens and the focal length f of the optical system satisfy: TTL / f≤4.0.

[0010] Furthermore, the F number of the optical system of the lens is ≤1.5.

[0011] Furthermore, the image height H of the optical system of the lens and the focal length f of the optical system satisfy: H / f≥1.0.

[0012] An imaging method for a large-aperture, large-target-surface, telephoto optical lens, wherein light rays sequentially pass through a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens from left to right to form an image.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. The lens uses seven optical lenses. Through the reasonable combination of spherical lenses and aspherical lenses, the system not only has high resolution and long focal length, but also solves the problems of small target surface and poor light transmission.

[0015] 2. The seven optical lenses of this lens are all made of glass material. Glass material has higher light transmittance than plastic material, and the large aperture design of this lens improves the light transmission capacity of the optical system.

[0016] 3. The lens also has the characteristics of good high and low temperature performance, low lens tolerance sensitivity, small distortion, good illumination uniformity, etc.; it can be matched with a chip with a larger target surface while taking into account the requirements of imaging quality and environmental adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the optical structure of the first embodiment of the present invention;

[0018] Figure 2 is a full-operating-band axial chromatic aberration diagram of the first embodiment of the present invention;

[0019] Figure 3 This is a vertical axis chromatic aberration diagram of the full working band of the first embodiment of the present invention;

[0020] Figure 4 This is a field curvature distortion diagram of the full working band of the first embodiment of the present invention;

[0021] Figure 5 is a schematic diagram of the optical structure of the second embodiment of the present invention;

[0022] Figure 6 is a full-operating-band axial chromatic aberration diagram of the second embodiment of the present invention;

[0023] Figure 7 This is a vertical axis chromatic aberration diagram of the full working band of the second embodiment of the present invention;

[0024] Figure 8 This is a field curvature distortion diagram of the full working band of the second embodiment of the present invention;

[0025] Fig. 9 is a schematic diagram of the optical structure of the third embodiment of the present invention;

[0026] Fig.10 is a full-operating-band axial chromatic aberration diagram of Embodiment 3 of the present invention;

[0027] Fig.11 This is a full-operating-band vertical-axis chromatic aberration diagram of Embodiment 3 of the present invention;

[0028] Fig.12 This is a field curvature distortion diagram of the full working band of the third embodiment of the present invention;

[0029] In the figure: L1-first lens; L2-second lens; STO-aperture; L3-third lens; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-seventh lens; L8-equivalent glass plate; IMA-imaging surface. DETAILED DESCRIPTION

[0030] In order to make the above features and advantages of the present invention more understandable, embodiments are given below with reference to the accompanying drawings for detailed description, but the present invention is not limited thereto.

[0031] Example 1 Reference Figures 1 to 4

[0032] A large aperture, large target surface, telephoto optical lens, comprising a first lens L1, a second lens L2, an aperture STO, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7, which are arranged in sequence from left to right along a light incident path; without considering the backcurvature caused by an aspheric coefficient, the first lens is a double concave negative lens, the second lens is a double convex positive lens, the third lens is a meniscus positive lens, the fourth lens is a double convex positive lens, the fifth lens is a double concave negative lens, the sixth lens is a double convex positive lens, and the seventh lens is a meniscus negative lens; wherein the fifth lens and the sixth lens are a cemented lens group.

[0033] In this embodiment, the first lens, the second lens, the fifth lens and the sixth lens are spherical lenses, and the third lens, the fourth lens and the seventh lens are aspherical lenses. The aspherical curve equation is expressed as:

[0034]

[0035] Wherein, Z is the height of the aspheric surface from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface; k is the cone constant; All are high-order coefficients.

[0036] In this embodiment, the first lens to the seventh lens are all made of glass material.

[0037] In this embodiment, the aspheric coefficients of the aspheric lenses of the optical system are as follows:

[0038] .

[0039] In this embodiment, the focal length of the optical system of the lens is , the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are respectively , , , , , , ,in , , , , , , and Meet the following ratio: -2.5< / <-0.5, 0.5< / <2.5, 3.5< / <5.5, 0.5< / <2.5, -2.5< / <-0.5, 0.5< / <2.5, -2.5< / <-0.5.

[0040] In this embodiment, the first lens satisfies the relationship: ≥1.5, ≥50.0; the second lens satisfies the relationship: ≤1.5, ≥50.0; the third lens satisfies the relationship: ≥1.5, ≥50.0; the fourth lens satisfies the relationship: ≥1.5, ≤50.0; the fifth lens satisfies the relationship: ≥1.5, ≤50.0; the sixth lens satisfies the relationship: ≥1.5, ≥50.0; The seventh lens satisfies the relationship: ≥1.5, ≤50.0; where is the refractive index, is the Abbe constant.

[0041] In this embodiment, the total optical length TTL of the optical system of the lens and the focal length f of the optical system satisfy: TTL / f≤4.0.

[0042] In this embodiment, the image height H of the optical system of the lens and the focal length f of the optical system satisfy: H / f≥1.0.

[0043] In this embodiment, the technical indicators achieved by the optical system are as follows:

[0044] (1) Focal length: 7.0 ≤ EFFL ≤ 9.0 mm;

[0045] (2) Aperture F ≤ 1.5;

[0046] (3) Field of view: 2w ≥ 60°;

[0047] (4) Working band: visible light band.

[0048] In this embodiment, in order to achieve the above design parameters, the specific design adopted by the optical system is shown in the following table:

[0049] .

[0050] In this embodiment, the optical system realizes a large target surface, a large aperture, a long focal length, and a low temperature drift design, while performing good corrections on-axis and off-axis aberrations.

[0051] Example 2 Reference Figures 5 to 8

[0052] A large aperture, large target surface, telephoto optical lens, comprising a first lens L1, a second lens L2, an aperture STO, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7, which are arranged in sequence from left to right along a light incident path; without considering the backcurvature caused by an aspheric coefficient, the first lens is a double concave negative lens, the second lens is a double convex positive lens, the third lens is a meniscus positive lens, the fourth lens is a double convex positive lens, the fifth lens is a double concave negative lens, the sixth lens is a double convex positive lens, and the seventh lens is a meniscus negative lens; wherein the fifth lens and the sixth lens are a cemented lens group.

[0053] In this embodiment, the first lens, the second lens, the fifth lens and the sixth lens are spherical lenses, the third lens, the fourth lens and the seventh lens are aspherical lenses, and the aspherical curve equation is expressed as:

[0054]

[0055] Wherein, Z is the height of the aspheric surface from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface; k is the cone constant; All are high-order coefficients.

[0056] In this embodiment, the first lens to the seventh lens are all made of glass material.

[0057] In this embodiment, the aspheric coefficients of the aspheric lenses of the optical system are as follows:

[0058] .

[0059] In this embodiment, the focal length of the optical system of the lens is , the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are respectively , , , , , , ,in , , , , , , and Meet the following ratio: -2.5< / <-0.5, 0.5< / <2.5, 3.5< / <5.5, 0.5< / <2.5, -2.5< / <-0.5, 0.5< / <2.5, -2.5< / <-0.5.

[0060] In this embodiment, the first lens satisfies the relationship: ≥1.5, ≥50.0; the second lens satisfies the relationship: ≤1.5, ≥50.0; the third lens satisfies the relationship: ≥1.5, ≥50.0; the fourth lens satisfies the relationship: ≥1.5, ≤50.0; the fifth lens satisfies the relationship: ≥1.5, ≤50.0; the sixth lens satisfies the relationship: ≥1.5, ≥50.0; The seventh lens satisfies the relationship: ≥1.5, ≤50.0; where is the refractive index, is the Abbe constant.

[0061] In this embodiment, the total optical length TTL of the optical system of the lens and the focal length f of the optical system satisfy: TTL / f≤4.0.

[0062] In this embodiment, the image height H of the optical system of the lens and the focal length f of the optical system satisfy: H / f≥1.0.

[0063] In this embodiment, the technical indicators achieved by the optical system are as follows:

[0064] (1) Focal length: 7.00 ≤ EFFL ≤ 8.00 mm;

[0065] (2) Aperture F ≤ 1.5;

[0066] (3) Field of view: 2w ≥ 60°;

[0067] (4) Working band: visible light band.

[0068] In this embodiment, in order to achieve the above design parameters, the specific design adopted by the optical system is shown in the following table:

[0069] .

[0070] In this embodiment, the optical system realizes a large target surface, a large aperture, a long focal length, and a low temperature drift design, while performing good corrections on-axis and off-axis aberrations.

[0071] Example 3 Reference Figures 9 to 12

[0072] A large aperture, large target surface, telephoto optical lens, comprising a first lens L1, a second lens L2, a stop STO, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 arranged in sequence from left to right along the incident light path of the light; without considering the backcurvature caused by the aspheric coefficient, the first lens is a double concave negative lens, the second lens is a double convex positive lens, the third lens is a meniscus positive lens, the fourth lens is a double convex positive lens, the fifth lens is a double concave negative lens, the sixth lens is a double convex positive lens, and the seventh lens is a meniscus negative lens; wherein the fifth lens and the sixth lens are a cemented lens group. The first lens to the seventh lens are all made of glass material.

[0073] In this embodiment, the first lens, the second lens, the fifth lens and the sixth lens are glass spherical lenses, and the third lens, the fourth lens and the seventh lens are glass aspherical lenses. The aspherical curve equation is:

[0074]

[0075] Wherein, Z is the height of the aspheric surface from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface; k is the cone constant; All are high-order coefficients.

[0076] In this embodiment, the aspheric coefficients of the aspheric lenses of the optical system are as follows:

[0077] .

[0078] In this embodiment, the focal length of the optical system of the lens is , the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are respectively , , , , , , ,in , , , ,,, and Meet the following ratio: -2.5< / <-0.5, 0.5< / <2.5, 3.5< / <5.5, 0.5< / <2.5, -2.5< / <-0.5, 0.5< / <2.5, -2.5< / <-0.5.

[0079] In this embodiment, the first lens satisfies the relationship: ≥1.5, ≥50.0; the second lens satisfies the relationship: ≤1.5, ≥50.0; the third lens satisfies the relationship: ≥1.5, ≥50.0; the fourth lens satisfies the relationship: ≥1.5, ≤50.0; the fifth lens satisfies the relationship: ≥1.5, ≤50.0; the sixth lens satisfies the relationship: ≥1.5, ≥50.0; The seventh lens satisfies the relationship: ≥1.5, ≤50.0; where is the refractive index, is the Abbe constant.

[0080] In this embodiment, the total optical length TTL of the optical system of the lens and the focal length f of the optical system satisfy: TTL / f≤4.0.

[0081] In this embodiment, the image height H of the optical system of the lens and the focal length f of the optical system satisfy: H / f≥1.0.

[0082] In this embodiment, the technical indicators achieved by the optical system are as follows:

[0083] (1) Focal length: 7.00 ≤ EFFL ≤ 8.00 mm;

[0084] (2) Aperture F ≤ 1.5;

[0085] (3) Field of view: 2w ≥ 60°;

[0086] (4) Working band: visible light band.

[0087] In this embodiment, in order to achieve the above design parameters, the specific design adopted by the optical system is shown in the following table:

[0088] .

[0089] In this embodiment, the optical system realizes a large target surface, a large aperture, a long focal length, and a low temperature drift design, while performing good corrections on-axis and off-axis aberrations.

[0090] In the imaging method of the large aperture large target surface telephoto optical lens, light is imaged after passing through a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens in sequence from left to right.

[0091] The above description is only a preferred embodiment of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, designing different forms of large-aperture, large-target-surface, long-focus optical lenses does not require creative labor. Without departing from the principles and spirit of the present invention, all equal changes, modifications, substitutions and variations made within the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A large aperture, large target surface, long focus optical lens, characterized in that: It is composed of a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are arranged in sequence from left to right along the incident optical path of the light; without considering the backcurvature caused by the aspheric coefficient, the first lens is a double concave negative lens, the second lens is a double convex positive lens, the third lens is a meniscus positive lens, the fourth lens is a double convex positive lens, the fifth lens is a double concave negative lens, the sixth lens is a double convex positive lens, and the seventh lens is a meniscus negative lens; wherein the fifth lens and the sixth lens are a cemented lens group; the first lens, the second lens, the fifth lens and the sixth lens are spherical lenses, and the third lens, the fourth lens and the seventh lens are aspherical lenses; the focal length of the optical system of the lens is , the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are respectively , , , , , , ,in , , , , , , and Meet the following ratio: -2.5< / <-0.5, 0.5< / <2.5, 3.5< / <5.5,0.5< / <2.5, -2.5< / <-0.5, 0.5< / <2.5, -2.5< / <-0.5; the first lens satisfies the relationship: ≥1.5, ≥50.0; the second lens satisfies the relationship: ≤1.5, ≥50.0; the third lens satisfies the relationship: ≥1.5, ≥50.0; the fourth lens satisfies the relationship: ≥1.5, ≤50.0; the fifth lens satisfies the relationship: ≥1.5, ≤50.0; the sixth lens satisfies the relationship: ≥1.5, ≥50.0; The seventh lens satisfies the relationship: ≥1.5, ≤50.0; where is the refractive index, is the Abbe constant; the total optical length TTL of the optical system of the lens and the focal length f of the optical system satisfy: TTL / f≤4.0; the F number of the optical system of the lens ≤1.5; the image height H of the optical system of the lens and the focal length f of the optical system satisfy: H / f≥1.

0.

2. The large aperture, large target surface, long focus optical lens according to claim 1, characterized in that: The first lens to the seventh lens are all made of glass material.

3. An imaging method applied to the large aperture, large target surface, and long focus optical lens as claimed in claim 1, characterized in that: The light passes through the first lens, the second lens, the aperture, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens from left to right to form an image.

Images