Wide-angle lens of small handheld motion camera and working method of wide-angle lens

Abstract

The invention relates to a small-sized handheld motion camera wide-angle lens and a working method thereof, the lens adopts an optical structure of a full-plastic lens, the advantage of aberration correction of an aspherical lens is brought into full play, high-definition imaging is met, the lens outer diameter is smaller, the optical total length is shorter, and miniaturization and low cost of the lens are guaranteed. The field angle of the lens for a 1 / 1. 3 ''imaging target surface is greater than 110 degrees, and the lens has the advantages of high imaging definition, large clear aperture, low tolerance sensitivity, good high and low temperature peak performance and the like, and can shoot a target more comprehensively.

Description

Technical Field

[0001] This invention relates to the field of lens technology, and in particular to a wide-angle lens for a small handheld action camera and its working method. Background Technology

[0002] Although the traditional camera industry has been impacted by the rise of mobile phone photography this century, imaging devices, especially smart imaging devices, remain irreplaceable in many fields. Benefiting from large-size CMOS sensors and wide-angle lens capabilities, smart imaging devices far surpass mobile phone lenses in image accuracy and quality. Therefore, the positioning of smart imaging devices has gradually shifted from everyday shooting tools to two main categories: specialized high-precision imaging devices for industrial applications (professional-grade smart imaging devices) or high-end consumer products focused on enhancing people's photography experience and meeting the photography needs of specific groups (consumer-grade smart imaging devices).

[0003] Driven by marketing efforts from brands like GoPro and Insta360, the consumer-grade handheld smart imaging device market has seen continuous growth in recent years. By 2022, the global market size had grown from RMB 16.43 billion in 2017 to RMB 30.75 billion, representing a compound annual growth rate (CAGR) of 13.4%. Currently, the consumer-grade handheld smart imaging device market has begun to take off, and the industry is expected to enter a period of rapid growth. However, lenses that combine large sensor size, low cost, wide spectrum, large relative aperture, miniaturization, and high image quality are currently relatively scarce. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a small handheld action camera wide-angle lens and its working method, which simultaneously takes into account optical characteristics such as large target area, low cost, wide spectrum, large relative aperture, miniaturization and high image quality.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A wide-angle lens for a small handheld action camera, characterized in that: the optical system of the lens comprises a first lens, a second lens, an aperture stop, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from left to right along the incident light path; the first lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; the second lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface; the third lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; the fourth lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; the fifth lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; the sixth lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; and the seventh lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; wherein the first, second, third, fourth, fifth, sixth, and seventh lenses are all plastic aspherical lenses.

[0007] Preferably, the focal length of the optical system is f, and the focal lengths of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, and seventh lens are f1, f2, f3, f4, f5, f6, and f7, respectively, wherein f1, f2, f3, f4, f5, f6, and f7 satisfy the following ratio with f: -3.0 <f1 / f<-2.0,-32.0<f2 / f<-31.0,1.0<f3 / f<2.0,-3.0<f4 / f<-2.0,-15.0<f5 / f<-14.0,1.0<f6 / f<2.0,-2.0<f7 / f<-1.0。

[0008] Preferably, the first lens satisfies the relationship: 1.5 ≤ N d ≤1.8, V d ≥50.0; The second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The third lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; The fourth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The fifth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; The sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; The seventh lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; where N d V is the refractive index. d Let be Abbe's constant.

[0009] Preferably, the on-axis distances between the lenses satisfy the following relationships: the air gap between the first lens and the second lens is 1.5–2.0 mm; the air gap between the second lens and the aperture stop is 0.0–0.5 mm; the air gap between the aperture stop and the third lens is 0.0–0.5 mm; the air gap between the third lens and the fourth lens is 0.0–0.5 mm; the air gap between the fourth lens and the fifth lens is 0.1–0.5 mm; the air gap between the fifth lens and the sixth lens is 0.1–0.5 mm; and the air gap between the sixth lens and the seventh lens is 1.0–1.5 mm.

[0010] Preferably, the first, second, third, fourth, fifth, sixth, and seventh lenses are all aspherical lenses. The equation for the aspherical curve is:

[0011]

[0012] Where Z is the distance from the vertex of the aspherical surface to the optical axis at a height of r; c is the paraxial curvature of the aspherical surface; k is the conic constant; and α1, α2, α3, α4, α5, α6, α7, and α8 are all higher-order coefficients.

[0013] Preferably, the total optical length (TTL) of the optical system and the focal length (f) of the optical system satisfy the following condition: TTL / f ≤ 2.5.

[0014] Preferably, the F-number of the optical system is ≤1.8.

[0015] Preferably, the image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f≤1.3.

[0016] Preferably, a filter is provided on the rear side of the seventh lens.

[0017] The present invention relates to a working method for a wide-angle lens of a small handheld action camera. Light rays pass sequentially from left to right through a first lens, a second lens, an aperture stop, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an equivalent glass plate before forming an image on the IMA-imaging plane. The first and second lenses are aspherical lenses with negative optical power, which adjust the large-angle light rays while reducing optical system distortion.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. This lens has a field of view of more than 110° for a 1 / 1.3" imaging target surface. At the same time, it has the advantages of high imaging clarity, large light transmission diameter, low tolerance sensitivity and good high and low temperature peak performance, which can capture the target more comprehensively.

[0020] 2. By rationally matching the various optical lenses, the system structure is compact and reasonable, easy to assemble, has low tolerance sensitivity, and is more suitable for large-scale high-yield production;

[0021] 3. The use of seven plastic lenses reduces costs while adapting to different environments;

[0022] 4. The chromatic aberration along each axis, the transverse chromatic aberration, and higher-order chromatic aberrations have been corrected to ensure that the imaging system can maintain high imaging quality even at large angles.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the optical structure of the present invention;

[0025] Figure 2 This is the axial chromatic aberration diagram of the entire working band of the present invention;

[0026] Figure 3 This is the transverse chromatic aberration diagram of the entire working band of the present invention;

[0027] Figure 4 This is the field curvature distortion diagram of the entire working band of the present invention;

[0028] In the diagram: STO - aperture stop; L1 - first lens; L2 - second lens; L3 - third lens; L4 - fourth lens; L5 - fifth lens; L6 - sixth lens; L7 - seventh lens; L8 - equivalent glass plate; IMA - imaging plane. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific implementation methods.

[0030] like Figure 1 As shown, the present invention relates to a small handheld action camera wide-angle lens. The optical system of the lens consists of a first lens, a second lens, an aperture stop, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from left to right along the incident light path. The first and second lenses are aspherical lenses with negative optical power, which adjust for large-angle light while reducing optical system distortion. This reasonable lens arrangement enables the optical system to achieve a low-cost, small-volume, and large-area design, while also providing good correction for on-axis and off-axis aberrations, resulting in good image quality. Figures 2 to 4 As shown.

[0031] Specifically, without considering the curvature caused by the aspherical coefficient, the first lens is a meniscus negative lens with a convex object side and a concave image side; the second lens is a meniscus negative lens with a concave object side and a convex image side; the third lens is a biconvex positive lens with a convex object side and a convex image side; the fourth lens is a meniscus negative lens with a convex object side and a concave image side; the fifth lens is a meniscus negative lens with a convex object side and a concave image side; the sixth lens is a biconvex positive lens with a convex object side and a convex image side; and the seventh lens is a meniscus negative lens with a convex object side and a concave image side. All lenses are made of plastic, with the first, second, third, fourth, fifth, sixth, and seventh lenses being plastic aspherical lenses.

[0032] The focal length of the optical system is f. The focal lengths of the first, second, third, fourth, fifth, sixth, and seventh lenses are f1, f2, f3, f4, f5, f6, and f7, respectively. The ratios of f1, f2, f3, f4, f5, f6, and f7 to f satisfy the following condition: -3.0 <f1 / f<-2.0,-32.0<f2 / f<-31.0,1.0<f3 / f<2.0,-3.0<f4 / f<-2.0,-15.0<f5 / f<-14.0,1.0<f6 / f<2.0,-2.0<f7 / f<-1.0。

[0033] The first lens satisfies the relationship: 1.5 ≤ N d ≤1.8, V d ≥50.0; The second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The third lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; The fourth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The fifth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; The sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; The seventh lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; where N d V is the refractive index. d Let be Abbe's constant.

[0034] The on-axis distances between the lenses satisfy the following relationships: the air gap between the first and second lenses is 1.5–2.0 mm; the air gap between the second lens and the aperture stop is 0.0–0.5 mm; the air gap between the aperture stop and the third lens is 0.0–0.5 mm; the air gap between the third and fourth lenses is 0.0–0.5 mm; the air gap between the fourth and fifth lenses is 0.1–0.5 mm; the air gap between the fifth and sixth lenses is 0.1–0.5 mm; and the air gap between the sixth and seventh lenses is 1.0–1.5 mm.

[0035] The equations for the aspherical curves of each lens are as follows:

[0036]

[0037] Where Z is the distance from the vertex of the aspherical surface to the optical axis at a height of r; c is the paraxial curvature of the aspherical surface; k is the conic constant; and α1, α2, α3, α4, α5, α6, α7, and α8 are all higher-order coefficients.

[0038] The total optical length (TTL) of the lens optical system and the focal length (f) of the optical system satisfy the following conditions: TTL / f ≤ 2.5; F-number of the optical system ≤ 1.8; image height (H) of the optical system and the focal length (f) of the optical system satisfy the following condition: H / f ≤ 1.3; the aperture stop of the optical system is located behind the second lens (S2); a filter is provided on the rear side of the seventh lens.

[0039] The technical specifications of the optical system achieved in a specific embodiment are as follows:

[0040] (1) Focal length: 4.0≤EFFL≤5.0mm;

[0041] (2) Aperture F≤1.8;

[0042] (3) Field of view: 2w ≥ 110°;

[0043] (4) Operating band: Visible light band.

[0044] To achieve the above design parameters, the specific design of the optical system adopted in this embodiment is shown in the table below:

[0045]

[0046]

[0047] The aspherical coefficients of the aspherical lenses of the optical system in the specific embodiment are shown in the table below:

[0048]

[0049] The optical system of this invention, by rationally allocating the optical power, surface shape, center thickness of each lens, and on-axis distance between each lens, can capture images of the target more comprehensively while satisfying the requirements of a field of view of the lens for a 1 / 1.3" imaging target surface greater than 110°, as well as high imaging clarity, large aperture, low tolerance sensitivity, and good high and low temperature peak performance.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A compact, hand-held action camera wide-angle lens, characterized by: The optical system of the lens is composed of a first lens, a second lens, a diaphragm, 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 light path of light incidence; the first lens is a meniscus concave negative lens, the object side surface of which is a convex surface and the image side surface of which is a concave surface; the second lens is a meniscus concave negative lens, the object side surface of which is a concave surface and the image side surface of which is a convex surface; the third lens is a double-convex positive lens, the object side surface of which is a convex surface and the image side surface of which is a convex surface; the fourth lens is a meniscus concave negative lens, the object side surface of which is a convex surface and the image side surface of which is a concave surface; the fifth lens is a meniscus concave negative lens, the object side surface of which is a convex surface and the image side surface of which is a concave surface; the sixth lens is a double-convex positive lens, the object side surface of which is a convex surface and the image side surface of which is a convex surface; and the seventh lens is a meniscus concave negative lens, the object side surface of which is a convex surface and the image side surface of which is a concave surface; each lens is a plastic aspheric lens.

2. The compact, hand-held action camera wide-angle lens of claim 1, wherein: The focal length of the optical system of the lens is f, and 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 f1, f2, f3, f4, f5, f6 and f7 respectively, wherein f1, f2, f3, f4, f5, f6 and f7 satisfy the following ratios: -3.0 < f1 / f < -2.0, -32.0 < f2 / f < -31.0, 1.0 < f3 / f < 2.0, -3.0 < f4 / f < -2.0, -15.0 < f5 / f < -14.0, 1.0 < f6 / f < 2.0 and -2.0 < f7 / f < -1.

0.

3. The compact, hand-held action camera wide-angle lens of claim 1, wherein: The first lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the second lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≤ 50.0; the third lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the fourth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≤ 50.0; the fifth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the sixth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the seventh lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≤ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

4. The compact, hand-held action camera wide-angle lens of claim 1, wherein: The on-axis distance between each lens of the lens satisfies the following relationship: the air gap between the first lens and the second lens is 1.5-2.0 mm; the air gap between the second lens and the diaphragm is 0.0-0.5 mm; the air gap between the diaphragm and the third lens is 0.0-0.5 mm; the air gap between the third lens and the fourth lens is 0.0-0.5 mm; the air gap between the fourth lens and the fifth lens is 0.1-0.5 mm; the air gap between the fifth lens and the sixth lens is 0.1-0.5 mm; and the air gap between the sixth lens and the seventh lens is 1.0-1.5 mm.

5. The compact, hand-held action camera wide-angle lens of claim 1, wherein: The aspheric curve equation expression of each lens of the lens is as follows: wherein Z is the sagittal height of the aspheric surface at a position with a height of r along the optical axis from the vertex of the aspheric surface; c is the paraxial curvature of the aspheric surface; k is the conic constant; and α1, α2, α3, α4, α5, α6, α7 and α8 are high-order coefficients.

6. The compact, hand-held action camera wide-angle lens of claim 1, wherein: The total optical length TTL of the optical system of the lens and the focal length f of the optical system satisfy TTL / f≤2.5; the F number of the optical system is ≤1.8; and the image height H of the optical system and the focal length f of the optical system satisfy H / f≤1.

3.

7. The wide-angle lens of a small-sized handheld motion camera according to claim 1, 2, 3, 4, 5 or 6, characterized in that: The technical indexes achieved by the optical system of the lens are as follows: (1) focal length: 4.0≤EFFL≤5.0 mm; (2) aperture: F≤1.8; (3) field of view: 2w≥110°; (4) working waveband: visible light waveband.

8. The compact, hand-held action camera wide-angle lens of claim 7, wherein: The parameters of the lens are shown in the following table:

9. The compact, hand-held action camera wide-angle lens of claim 8, wherein: The aspherical coefficients of each aspherical lens of the optical system of the lens are as follows:

10. The working method of the wide-angle lens of the small-sized handheld action camera according to claims 1-9, characterized in that: The light rays pass through the first lens, the second lens, the diaphragm, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the equivalent glass flat plate in sequence from left to right of the lens, and then are imaged on the IMA-imaging plane. The first lens and the second lens are aspherical lenses with negative focal power, which can adjust the large-angle light rays and reduce the distortion of the optical system.

Images