Equivalent 60mm standard lens

Abstract

The invention provides an equivalent 60mm standard lens. The equivalent 60mm standard lens consists of a diaphragm, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and plate glass in sequence from an object side surface to an image surface, the first lens is set to be a positive focal power lens, the second lens is set to be a negative focal power lens, the third lens is set to be a negative focal power lens, the fourth lens is set to be a negative focal power lens, the fifth lens is set to be a positive focal power lens, and the sixth lens is set to be a positive focal power lens; the first lens and the second lens meet the conditional expressions that phi 1 + phi 3 is larger than or equal to 0.072 and phi 1 / phi 3 is larger than or equal to 0.319, phi 1 represents the focal power of the first lens, and phi 3 represents the focal power of the third lens. The large field angle and the low optical distortion are considered, and meanwhile the characteristics of light weight and miniaturization are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of photographic lenses, and in particular to a 60mm equivalent standard lens. Background Art

[0002] With the increasing popularity of outdoor sports (such as cycling, driving, and traveling), users are increasingly demanding action cameras for capturing photos, especially when sharing photos on social media, seeking realistic and visually appealing images. Current mainstream action cameras generally use wide-angle lenses with a field of view of approximately 150°. This advantage lies in their ability to capture a wider range of scene information, making them suitable for shooting in confined or dynamic environments. However, these wide-angle lenses have significant drawbacks:

[0003] Image distortion problem: Wide-angle lenses (especially those with a focal length below 24mm) will produce barrel distortion, causing the edges of the image to stretch and deform. At the same time, the strong sense of perspective will distort the spatial relationship and destroy the true restoration of the scene.

[0004] Deviation of human visual perception: The viewing angle (45° to 50°) of a standard focal length lens (40-60mm) is closest to the human visual experience and can avoid exaggerated spatial compression or distortion. However, existing sports cameras are difficult to integrate with this focal length due to size limitations.

[0005] To address wide-angle distortion, existing technologies attempt to optimize optical performance through multi-lens lens structures. For example, seven aspherical lenses (made of glass and plastic) are combined to increase the aperture and field of view while limiting the overall lens length. However, such designs cannot fundamentally eliminate edge distortion, and their complex structure can increase manufacturing costs and pose thermal stability risks.

[0006] In summary, the market urgently needs a sports camera lens solution that combines a large field of view (to meet the needs of shooting sports scenes), low optical distortion (close to the natural visual effect of standard focal lengths), and a compact structure to break through the existing technical bottleneck. Summary of the Invention

[0007] In response to the above problems, the present invention provides a 60mm equivalent standard lens, which has a wide field of view, low optical distortion, and is lightweight and miniaturized.

[0008] To achieve the above object, the present invention solves it through the following technical solutions:

[0009] A 60mm equivalent standard lens, which consists of an aperture, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a flat glass in order from the object side to the image side;

[0010] The first lens is configured as a positive power lens, the second lens is configured as a negative power lens, the third lens is configured as a negative power lens, the fourth lens is configured as a negative power lens, the fifth lens is configured as a positive power lens, and the sixth lens is configured as a positive power lens;

[0011] It satisfies the conditional formula |Φ1+Φ3|≥0.072, |Φ1 / Φ3|≥0.319, where Φ1 represents the optical power of the first lens, and Φ3 represents the optical power of the third lens.

[0012] Preferably, it satisfies the conditional formula f3 / f4≤1.452, wherein f3 represents the focal length of the third lens, and f4 represents the focal length of the fourth lens.

[0013] Preferably, it satisfies the conditional expression f6 / f≥3.77, wherein f6 is the focal length of the sixth lens, and f is the focal length of the standard lens.

[0014] Preferably, it satisfies the conditional formula TTL / ImgH≤2.872, wherein TTL is the distance from the object side surface of the first lens to the image plane on the optical axis, and ImgH is half the length of the diagonal of the effective imaging area of ​​the standard lens.

[0015] Preferably, it satisfies the conditional formula ImgH / Fno≥2.7, wherein ImgH is half of the diagonal length of the effective imaging area of ​​the standard lens, and Fno is the aperture number of the standard lens.

[0016] Preferably, the conditional formula SAG61 / CT6≤0.377 is satisfied, wherein SAG61 represents the displacement from the intersection of the objective side surface of the sixth lens and the optical axis to the boundary of the optically effective area of ​​the objective side surface of the sixth lens parallel to the optical axis, and CT6 represents the maximum thickness of the sixth lens on the optical axis.

[0017] Preferably, it satisfies the conditional formula (CT6-SAG61+SAG62) / CT6≥0.454, wherein CT6 is the maximum thickness of the sixth lens on the optical axis, SAG61 represents the displacement from the intersection of the object side surface of the sixth lens and the optical axis to the boundary of the optically effective area of ​​the object side surface of the sixth lens parallel to the optical axis, and SAG62 represents the displacement from the intersection of the image side surface of the sixth lens and the optical axis to the boundary of the optically effective area of ​​the image surface of the sixth lens parallel to the optical axis.

[0018] Preferably, it satisfies the conditional formula |R9 / f5|≥0.219, wherein R9 represents the radius of curvature of the object-side surface of the fifth lens, and f6 is the focal length of the sixth lens.

[0019] Preferably, it satisfies the conditional formula f56 / f≤1.911, wherein f56 represents the combined focal length of the fifth lens and the sixth lens, and f represents the focal length of the equivalent 60mm standard lens.

[0020] The beneficial effects of the present invention are:

[0021] 1. The conditions |Φ1+Φ3|≥0.072, |Φ1 / Φ3|≥0.319 are satisfied, and TTL≤15.862m is achieved, thereby making the present invention lightweight and miniaturized;

[0022] 2. Satisfying the condition f3 / f4 ≤ 1.452, by adjusting the focal length ratio of the third and fourth lenses, helps increase the symmetry of the equivalent 60mm standard lens and reduce the spot size in the center field of view;

[0023] 3. If the condition f6 / f ≥ 3.77 is met, the ratio of the focal length of the sixth lens to the focal length of the entire lens can be adjusted to reduce the sensitivity of the sixth lens.

[0024] 4. The conditional formula TTL / ImgH ≤ 2.872 is met to ensure that the equivalent 60mm standard lens has a large image area and is compact;

[0025] 5. The conditional formula ImgH / Fno ≥ 2.7 is met to ensure a large target area equivalent to a 60mm standard lens while also having a large aperture to increase the amount of light entering;

[0026] 6. The conditional formula SAG61 / CT6 ≤ 0.377 is satisfied. By adjusting the ratio of the effective semi-aperture vertex of the object side of the sixth lens on the optical axis to the maximum thickness of the sixth lens on the optical axis, the machinability of the sixth lens is improved while reducing sensitivity, thereby increasing manufacturing yield.

[0027] 7. The conditional formula (CT6 - SAG61 + SAG62) / CT6 ≥ 0.454 is satisfied. By adjusting the ratio of the thickness of the sixth lens at its maximum effective aperture to its thickness at the optical axis, the manufacturing feasibility of the sixth lens is improved.

[0028] 8. The condition |R9 / f5|≥0.219 is satisfied. By adjusting the ratio of the radius of curvature of the object-side surface of the fifth lens to the focal length of the sixth lens, the fifth lens is ensured to smoothly receive light passing through the fourth lens. This allows light rays with smaller angles to pass through the fifth lens, reducing higher-order aberrations introduced by the rear optical path and improving image quality.

[0029] 9. When the condition f56 / f ≤ 1.911 is satisfied, the focal length of the fifth and sixth lenses is adjusted relative to the focal length of an equivalent 60mm standard lens to increase the focal power of the rear-end optical system lens group. This, in turn, reduces the incident angle of the principal ray, better matches the CRA curve of the receiving chip, and improves relative illumination. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic cross-sectional structural diagram of a first embodiment of the present invention;

[0031] Figure 2 is an optical transfer function curve diagram of the first embodiment of the present invention;

[0032] Figure 3 is a spot diagram of the first embodiment of the present invention;

[0033] Figure 4 is a schematic cross-sectional structural diagram of a second embodiment of the present invention;

[0034] Figure 5 is an optical transfer function curve diagram of the second embodiment of the present invention;

[0035] Figure 6 is a spot diagram of a second embodiment of the present invention;

[0036] Figure 7 is a schematic cross-sectional view of a third embodiment of the present invention;

[0037] Figure 8 is an optical transfer function curve diagram of the third embodiment of the present invention;

[0038] Figure 9 FIG. 4 is a spot diagram of the third embodiment of the present invention.

[0039] Reference numerals are: image plane 10 , aperture 18 , first lens 12 , second lens 13 , third lens 14 , fourth lens 15 , fifth lens 16 , sixth lens 17 , and flat glass 11 . DETAILED DESCRIPTION

[0040] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate several embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] In this embodiment, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the position of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is undefined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image surface of the lens.

[0043] The present invention provides a 60mm equivalent standard lens, which comprises, from the object side to the image plane 10, an aperture 18, a first lens 12, a second lens 13, a third lens 14, a fourth lens 15, a fifth lens 16, a sixth lens 17, and a flat glass 11. The first lens 12 is configured as a positive power lens, the second lens 13 is configured as a negative power lens, the third lens 14 is configured as a negative power lens, the fourth lens 15 is configured as a negative power lens, the fifth lens 16 is configured as a positive power lens, and the sixth lens 17 is configured as a positive power lens. The lens satisfies the following condition:

[0044] |Φ1+Φ3|≥0.072, |Φ1 / Φ3|≥0.319, where Φ1 represents the focal length of the first lens 12, and Φ3 represents the focal length of the third lens 14, achieving TTL≤15.862m, thereby making the present invention lightweight and miniaturized.

[0045] It satisfies the conditional formula f3 / f4≤1.452, where f3 represents the focal length of the third lens 14 and f4 represents the focal length of the fourth lens 15. By adjusting the focal length ratio of the third lens and the fourth lens, it helps to increase the symmetry of the equivalent 60mm standard lens and reduce the spot size of the central field of view.

[0046] It satisfies the conditional expression f6 / f≥3.77, where f6 is the focal length of the sixth lens 17 and f is the focal length of the standard lens. The ratio of the focal length of the sixth lens to the focal length of the entire lens can be adjusted to reduce the sensitivity of the sixth lens.

[0047] It satisfies the conditional formula TTL / ImgH≤2.872, where TTL is the distance from the object side surface of the first lens 12 to the image plane 10 on the optical axis, and ImgH is half the length of the diagonal of the effective imaging area of ​​the standard lens, ensuring that the equivalent 60mm standard lens has a large image surface and is miniaturized.

[0048] It satisfies the conditional formula ImgH / Fno≥2.7, where ImgH is half of the diagonal length of the effective imaging area of ​​the standard lens, and Fno is the aperture number of the standard lens, ensuring a large target surface equivalent to a 60mm standard lens while having a large aperture to increase the amount of light entering.

[0049] The conditional equation SAG61 / CT6 ≤ 0.377 is satisfied, where SAG61 represents the displacement from the intersection of the object side surface of the sixth lens 17 and the optical axis to the boundary of the optically effective area of ​​the object side surface of the sixth lens 17 parallel to the optical axis, and CT6 represents the maximum thickness of the sixth lens 17 on the optical axis. By adjusting the ratio of the distance between the effective semi-aperture vertex of the object side surface of the sixth lens on the optical axis and the maximum thickness of the sixth lens on the optical axis, the machinability of the sixth lens is improved while the sensitivity is reduced, thereby improving the manufacturing yield.

[0050] It satisfies the conditional formula (CT6-SAG61+SAG62) / CT6≥0.454, where CT6 is the maximum thickness of the sixth lens element 17 on the optical axis, SAG61 represents the displacement from the intersection of the object side surface of the sixth lens element 17 and the optical axis to the boundary of the optically effective area of ​​the object side surface of the sixth lens element 17 parallel to the optical axis, and SAG62 represents the displacement from the intersection of the image plane 10 side of the sixth lens element 17 and the optical axis to the boundary of the optically effective area of ​​the image plane 10 of the sixth lens element 17 parallel to the optical axis. By adjusting the ratio between the thickness of the sixth lens element at the maximum effective aperture and the thickness of the sixth lens element at the optical axis, the manufacturing feasibility of the sixth lens element is improved.

[0051] The conditional formula |R9 / f5|≥0.219 is satisfied, where R9 represents the radius of curvature of the object-side surface of the fifth lens 16, and f6 is the focal length of the sixth lens 17. By adjusting the ratio of the radius of curvature of the object-side surface of the fifth lens to the focal length of the sixth lens, the fifth lens is ensured to smoothly receive light passing through the fourth lens, allowing light of a smaller angle to pass through the fifth lens, thereby reducing high-order aberrations introduced by the rear-end optical path and improving image quality.

[0052] The conditional formula f56 / f≤1.911 is satisfied, where f56 represents the combined focal length of the fifth lens 16 and the sixth lens 17, and f represents the focal length of the equivalent 60mm standard lens. By adjusting the ratio of the combined focal length of the fifth lens and the sixth lens to the focal length of the equivalent 60mm standard lens, the optical power of the lens group of the rear-end optical system is improved, thereby reducing the incident angle of the main light, better matching the CRA curve of the receiving chip, and improving the relative illumination.

[0053] Through the above configuration, the present invention can take into account a large field of view angle, low optical distortion, and has the characteristics of lightness and miniaturization.

[0054] For the first example, please refer to Figure 1-3 The first embodiment of the present invention provides an equivalent 60mm standard lens. The relevant parameters of each lens in the lens are shown in Table 1-1, and the parameters of the aspheric surfaces of each lens in this embodiment are shown in Table 1-2.

[0055] Table 1-1

[0056]

[0057] Table 1-2

[0058]

[0059] The aspheric surfaces all satisfy the following equation:

[0060]

[0061] Where: z represents the distance vector from the aspheric surface vertex along the optical axis when the distance from the optical axis to the surface is h, c represents the curvature of the surface vertex, K represents the quadratic surface coefficient, and B, C, D, E, F, G, and H represent the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients, respectively. All aspheric surface shapes meet this formula.

[0062] In the first embodiment, the system focal length f=14.625 mm, FNO=2.0, the field of view angle is 39.6 degrees, and the system total length TOTR=15.862 mm. Table 1-3 shows the conditional calculation results.

[0063] Table 1-3

[0064] Conditional expression actual result |Φ1+Φ3|≥0.072 0.072 conform to |Φ1 / Φ3|≥0.319 0.319 conform to f3 / f4≤1.452 1.452 conform to f6 / f≥3.77 4.011 conform to TTL / ImgH≤2.872 2.872 conform to ImgH / Fno≥2.7 2.752 conform to SAG61 / CT6≤0.377 0.377 conform to (CT6-SAG61+SAG62) / CT6≥0.454 0.504 conform to |R9 / f5|≥0.219 0.219 conform to f56 / f≤1.911 1.911 conform to

[0065] For the second embodiment, please refer to Figures 4-6 The second embodiment of the present invention provides an equivalent 60mm standard lens, and the relevant parameters of each lens are shown in Table 2-1. The parameters of the aspherical surfaces of each lens in this embodiment are shown in Table 2-2.

[0066] Table 2-1

[0067]

[0068] Table 2-2

[0069]

[0070] The aspheric surfaces all satisfy the following equation:

[0071]

[0072] Where: z represents the distance vector from the aspheric surface vertex along the optical axis when the distance from the optical axis to the surface is h, c represents the curvature of the surface vertex, K represents the quadratic surface coefficient, and B, C, D, E, F, G, and H represent the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients, respectively. All aspheric surface shapes meet this formula.

[0073] In the second embodiment, the system focal length f = 14.50 mm, FNO = 2.0, the field of view angle is 40.6 degrees, and the system total length TOTR = 15.86 mm. Table 2-3 shows the conditional calculation results.

[0074] Table 2-3

[0075] Conditional expression actual result |Φ1+Φ3|≥0.072 0.072 conform to |Φ1 / Φ3|≥0.319 0.324 conform to f3 / f4≤1.452 1.418 conform to f6 / f≥3.77 3.770 conform to TTL / ImgH≤2.872 2.937 conform to ImgH / Fno≥2.7 2.700 conform to SAG61 / CT6≤0.377 0.377 conform to (CT6-SAG61+SAG62) / CT6≥0.454 0.454 conform to |R9 / f5|≥0.219 0.229 conform to f56 / f≤1.911 1.823 conform to

[0076] For the third embodiment, please refer to Figures 7-9 The third embodiment of the present invention provides an equivalent 60mm standard lens, and the parameters of each lens are shown in Table 3-1. The parameters of the aspheric surfaces of each lens in this embodiment are shown in Table 3-2.

[0077] Table 3-1

[0078]

[0079]

[0080] Table 3-2

[0081]

[0082] The aspheric surfaces all satisfy the following equation:

[0083]

[0084] Where: z represents the distance vector from the aspheric surface vertex along the optical axis when the distance from the optical axis to the surface is h, c represents the curvature of the surface vertex, K represents the quadratic surface coefficient, and B, C, D, E, F, G, and H represent the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients, respectively. All aspheric surface shapes meet this formula.

[0085] In the third embodiment, the system focal length f = 14.526 mm, FNO = 2.0, the field of view angle is 40.6 degrees, and the system total length TOTR = 15.841 mm. Table 3-3 shows the conditional calculation results.

[0086] Table 3-3

[0087]

[0088]

[0089] The above-described embodiments merely represent three implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A 60 mm equivalent standard lens, comprising, from the object side to the image side (10), an aperture (18), a first lens (12), a second lens (13), a third lens (14), a fourth lens (15), a fifth lens (16), a sixth lens (17), and a flat glass (11); Its characteristics are: The first lens (12) is configured as a positive power lens, the second lens (13) is configured as a negative power lens, the third lens (14) is configured as a negative power lens, the fourth lens (15) is configured as a negative power lens, the fifth lens (16) is configured as a positive power lens, and the sixth lens (17) is configured as a positive power lens; It satisfies the condition: |Φ1+Φ3|≥0.072, |Φ1 / Φ3|≥0.319, wherein Φ1 represents the optical focal length of the first lens (12), and Φ3 represents the optical focal length of the third lens (14).

2. The 60mm equivalent standard lens according to claim 1, characterized in that: It satisfies the conditional formula f3 / f4≤1.452, wherein f3 represents the focal length of the third lens (14), and f4 represents the focal length of the fourth lens (15).

3. The 60mm equivalent standard lens according to claim 1, characterized in that: It satisfies the conditional formula f6 / f≥3.77, wherein f6 is the focal length of the sixth lens (17), and f is the focal length of the standard lens.

4. The 60mm equivalent standard lens according to claim 1, characterized in that: It satisfies the conditional formula TTL / ImgH≤2.872, wherein TTL is the distance from the object side of the first lens (12) to the image plane (10) on the optical axis, and ImgH is half the length of the diagonal of the effective imaging area of ​​the standard lens.

5. The 60mm equivalent standard lens according to claim 1, characterized in that: It satisfies the conditional formula ImgH / Fno≥2.7, wherein ImgH is half of the diagonal length of the effective imaging area of ​​the standard lens, and Fno is the aperture number of the standard lens.

6. The 60mm equivalent standard lens according to claim 1, characterized in that: It satisfies the conditional formula SAG61 / CT6≤0.377, wherein SAG61 represents the displacement from the intersection of the object side surface of the sixth lens (17) and the optical axis to the boundary of the optically effective area of ​​the object side surface of the sixth lens (17) parallel to the optical axis, and CT6 represents the maximum thickness of the sixth lens (17) on the optical axis.

7. The 60mm equivalent standard lens according to claim 1, characterized in that: It satisfies the conditional formula (CT6-SAG61+SAG62) / CT6≥0.454, wherein CT6 is the maximum thickness of the sixth lens (17) on the optical axis, SAG61 represents the displacement from the intersection of the object side surface of the sixth lens (17) and the optical axis to the boundary of the optically effective area of ​​the object side surface of the sixth lens (17) parallel to the optical axis, and SAG62 represents the displacement from the intersection of the image plane (10) side of the sixth lens (17) and the optical axis to the boundary of the optically effective area of ​​the image plane (10) of the sixth lens (17) parallel to the optical axis.

8. The 60mm equivalent standard lens according to claim 1, characterized in that: It satisfies the conditional formula |R9 / f5|≥0.219, wherein R9 represents the radius of curvature of the object side surface of the fifth lens (16), and f6 is the focal length of the sixth lens (17).

9. The 60mm equivalent standard lens according to claim 1, characterized in that: It satisfies the conditional formula f56 / f≤1.911, wherein f56 represents the combined focal length of the fifth lens (16) and the sixth lens (17), and f represents the focal length of the equivalent 60mm standard lens.

Images