Optical lens and imaging device

Abstract

The present application relates to an optical lens and an imaging device, the optical lens comprising six lenses arranged along an optical axis from an object side to an image side in sequence, which are a first lens with negative refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens with positive refractive power, a fifth lens with positive refractive power and a sixth lens with negative refractive power. The optical lens satisfies FOV >= 180°, f / OTTL >= 0.110, wherein FOV is the maximum field of view angle of the optical lens, f is the total effective focal length of the optical lens, and OTTL is the total optical length of the optical lens. The imaging device of the present application comprises the above optical lens and an imaging element for converting the optical image formed by the optical lens into an electrical signal. The imaging device can maintain high imaging quality while improving the imaging field of view angle, is suitable for various electronic devices, and can be applied to unmanned aerial vehicles, vehicle-mounted surround view image devices and the like that need to be equipped with surround view optical image capturing requirements.

Description

Technical Field

[0001] This invention relates to optical lenses and imaging devices, and particularly to an optical lens and imaging device comprising six lenses. Background Technology

[0002] With the rapid development of science and technology, especially electronic technology, drones and vehicle surround-view imaging have become increasingly widespread, driving the vigorous development of imaging module technologies used in electronic devices. Imaging modules are being used more and more extensively, such as in drones, vehicle surround-view imaging, and panoramic shooting. As these electronic products continue to upgrade, people are demanding greater and greater field of view from lenses. Traditional lens structures, with their refractive power configurations, cannot maintain high image quality while meeting the requirements for surround-view imaging. Summary of the Invention

[0003] The purpose of this invention is to provide an optical lens and imaging device that can maintain high imaging quality while increasing the imaging field of view.

[0004] An optical lens includes six lenses: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, arranged sequentially from the object side to the image side along the optical axis. The first lens has negative refractive power, with its object side being convex near the optical axis and its image side being concave near the optical axis. The second lens has negative refractive power, with its image side being concave near the optical axis. The third lens has positive refractive power, with its object side being convex near the optical axis and its image side being concave near the optical axis. The fourth lens has positive refractive power, with both its object and image sides being convex near the optical axis. The fifth lens has positive refractive power, with both its object and image sides being convex near the optical axis. The sixth lens has negative refractive power, with both its object and image sides being concave near the optical axis. The optical lens satisfies FOV≥180° and f / OTTL≥0.110, where FOV is the maximum field of view of the optical lens, f is the total effective focal length of the optical lens, and OTTL is the total optical length of the optical lens.

[0005] Preferably, the optical lens satisfies (CT1 / ET1)+(CT2 / ET2)≥0.7, where CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, ET1 is the edge thickness of the first lens, and ET2 is the edge thickness of the second lens.

[0006] Preferably, the maximum F-theta distortion of the optical lens across the entire field of view is less than or equal to 10%.

[0007] Preferably, the optical lens further includes an aperture stop located between the third and fourth lenses and a filter located on the image side of the sixth lens. The optical lens satisfies 1.85 ≤ FNO ≤ 2.1, where FNO is the relative aperture of the optical lens.

[0008] Preferably, the optical lens satisfies ATmax / CTmax≤0.6, where ATmax is the maximum distance between adjacent lenses on the optical axis, and CTmax is the maximum thickness of the lens with the largest thickness on the optical axis among the six lenses.

[0009] Preferably, the optical lens satisfies 0.1≤CT4 / ΣCT≤0.3, where CT4 is the thickness of the fourth lens on the optical axis, and ΣCT is the sum of the thicknesses of the six lenses on the optical axis.

[0010] Preferably, the optical lens satisfies the following condition: 2≤f3 / f4≤5, where f3 is the focal length of the third lens and f4 is the focal length of the fourth lens.

[0011] Preferably, the object-side and image-side surfaces of the first and fourth lenses are both glass spherical surfaces, while the object-side and image-side surfaces of the second, third, fifth, and sixth lenses are plastic aspherical surfaces.

[0012] Preferably, the optical lens satisfies L1D1 / f≤9.5, where L1D1 is the effective optical dimension of the object-side surface of the first lens. The optical lens also satisfies |L4R1 / L4R2|≥0.9, where L4R1 is the radius of curvature of the object-side surface of the fourth lens, and L4R2 is the radius of curvature of the image-side surface of the fourth lens.

[0013] The imaging device of the present invention includes the aforementioned optical lens and an imaging element for converting the optical image formed by the optical lens into an electrical signal. This imaging device can maintain high imaging quality while increasing the imaging field of view, is compatible with various electronic devices, and can be applied to drones, vehicle-mounted surround-view imaging devices, and other applications requiring surround-view optical imaging. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the imaging device according to Embodiment 1 of the present invention.

[0015] Figure 2 This is a graph showing the astigmatism and distortion curves of the imaging device in Embodiment 1 of the present invention.

[0016] Figure 3 This is a schematic diagram of the imaging device according to Embodiment 2 of the present invention.

[0017] Figure 4 This is a graph showing the astigmatism and distortion curves of the imaging device in Embodiment 2 of the present invention.

[0018] Figure 5 This is a schematic diagram of the imaging device according to Embodiment 3 of the present invention.

[0019] Figure 6 This is a graph showing the astigmatism and distortion curves of the imaging device in Embodiment 3 of the present invention.

[0020] Figure 7 This is a schematic diagram of the imaging device according to Embodiment 4 of the present invention.

[0021] Figure 8 This is a graph showing the astigmatism and distortion curves of the imaging device in Embodiment 4 of the present invention.

[0022] Figure 9 This is a schematic diagram of the imaging device according to Embodiment 5 of the present invention.

[0023] Figure 10 This is a graph showing the astigmatism and distortion curves of the imaging device in Embodiment 5 of the present invention. Detailed Implementation

[0024] In the description of this invention, the object side of a lens refers to the side of the lens facing the object, and the image side refers to the side of the lens facing the imaging plane. When a cross-section is made at any point on the object side surface of the lens, if the object side surface is always located on the image side of the cross-section and its radius of curvature is positive, then the object side surface of the lens is convex; otherwise, the object side surface of the lens is concave. When a cross-section is made at any point on the image side surface of the lens, if the image side surface is always on the object side of the cross-section and its radius of curvature is negative, then the image side surface of the lens is convex; otherwise, the image side surface of the lens is concave. If a cross-section is made at any point on the object side surface or the cross-section of the image side surface of the lens, and the object side surface or the image side surface is partially on the image side of the cross-section and partially on the object side of the cross-section, then the surface has a point of inflection. The determination of the concavity or convexity of the object side and image side surfaces near the optical axis still applies to the above method.

[0025] Furthermore, the equations for the aspherical curves of each aspherical lens are expressed as follows: (1) Where Z is the distance vector from the origin of the aspherical surface at a height of r along the optical axis; c is the paraxial curvature of the aspherical surface (radius of curvature R = 1 / c, which is the reciprocal of the curvature); k is the conic coefficient; Ai is the i-th order coefficient of the aspherical surface, and the higher order coefficients used in this invention are A4, A6, A8, and A... 10 A 12 A 14 A 16 .

[0026] The imaging device of the present invention mainly includes a housing with a through hole, an optical lens assembled within the housing, and an imaging element for converting the optical image formed by the optical lens into an electrical signal. The imaging element is disposed on the imaging surface of the optical lens. The optical lens includes six mutually isolated lenses with optical power, namely a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first to sixth lenses are arranged sequentially and at intervals along the optical axis from the object side to the image side.

[0027] The first lens has negative refractive power, with its object-side surface being convex near the optical axis and its image-side surface being concave near the optical axis. This configuration of the first lens allows it to effectively collect edge rays, increasing light transmission and helping to reduce aberrations and facilitate large field-of-view imaging.

[0028] The second lens has negative refractive power, and its image-side surface is concave near the optical axis. The placement of the second lens facilitates the convergence of peripheral light rays, eliminating off-axis astigmatism.

[0029] The third lens has positive refractive power; its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis. The configuration of the third lens allows it to balance off-axis aberrations.

[0030] The fourth lens has positive refractive power, and both its object-side and image-side surfaces are convex near the optical axis. This configuration allows the fourth lens to effectively correct paraxial spherical aberration and balance higher-order aberrations in the optical system.

[0031] The fifth lens has positive refractive power, and both its object-side and image-side surfaces are convex near the optical axis. This configuration of the fifth lens helps to further eliminate higher-order aberrations.

[0032] The sixth lens has negative refractive power, and its object-side surface is concave near the optical axis, while its image-side surface is also concave near the optical axis. The configuration of the sixth lens helps to move the principal point of the optical imaging system away from the image-side end, thereby effectively shortening the overall length of the optical imaging system. At the same time, it can correct off-axis aberrations to improve peripheral image quality.

[0033] Furthermore, the optical lens meets the requirements of FOV ≥ 180° and f / OTTL ≥ 0.110, where FOV is the maximum field of view of the optical lens, f is the total effective focal length of the optical lens, and OTTL is the total optical length of the optical lens. A field of view of 180° or more ensures sufficient field of view to meet the requirements of panoramic image capture. An f / OTTL ≥ 0.110 keeps the overall size of the lens within a reasonable range, allowing it to meet a wider range of application structural requirements.

[0034] The optical lens can also optionally satisfy (CT1 / ET1)+(CT2 / ET2)≥0.7, where CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, ET1 is the edge thickness of the first lens, and ET2 is the edge thickness of the second lens. This configuration can effectively control the thickness ratio of the first and second lenses in the optical lens, helping to ensure the manufacturability of the lens.

[0035] The optical lens can also optionally have a maximum F-theta distortion of less than or equal to 10% across the entire field of view. This configuration helps to keep the distortion of the shooting angle and the actual linearity of the image on the image plane within a reasonable range, ensuring the effect of the final product.

[0036] The optical lens may optionally include an aperture stop located between the third and fourth lenses and a filter located on the image side of the sixth lens. The aperture stop improves image quality, and the filter can be used to correct chromatic aberration. The optical lens satisfies 1.85 ≤ FNO ≤ 2.1, where FNO is the relative aperture of the optical lens. This configuration ensures that the overall optical lens has both a wide angle and sufficient light intake.

[0037] The optical lenses can also optionally satisfy ATmax / CTmax ≤ 0.6, where ATmax is the maximum distance between adjacent lenses on the optical axis, and CTmax is the maximum thickness of the lens with the largest thickness on the optical axis among the six lenses. This configuration can effectively balance the optical lens configuration to achieve better space utilization.

[0038] The optical lens can also optionally satisfy 0.1≤CT4 / ΣCT≤0.3, where CT4 is the thickness of the fourth lens on the optical axis, and ΣCT is the sum of the thicknesses of the six lenses on the optical axis. This configuration ensures uniformity of lens dimensions and facilitates lens processing and assembly.

[0039] The optical lens may also optionally satisfy the following condition: 2 ≤ f3 / f4 ≤ 5, where f3 is the focal length of the third lens and f4 is the focal length of the fourth lens. This configuration balances the refractive power of the optical lens, effectively reducing sensitivity.

[0040] Optionally, the object-side and image-side surfaces of the first and fourth lenses are both made of glass spherical surfaces, while the object-side and image-side surfaces of the second, third, fifth, and sixth lenses are made of plastic aspherical surfaces. This six-element structure, combining two glass elements and four plastic elements, provides better aberration correction.

[0041] The optical lens may also optionally satisfy L1D1 / f≤9.5, where L1D1 is the effective optical dimension of the object-side surface of the first lens. This configuration allows for control of the size of the first lens, and a reasonable first lens volume facilitates subsequent structural design and manufacturing. The optical lens may also optionally satisfy |L4R1 / L4R2|≥0.9, where L4R1 is the radius of curvature of the object-side surface of the fourth lens, and L4R2 is the radius of curvature of the image-side surface of the fourth lens. This configuration helps the lens with positive refractive power to better converge light, helps eliminate spherical aberration, and contributes to a more uniform shape, reducing its tolerance sensitivity.

[0042] Specific embodiments of the imaging device applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0043] Example 1: like Figure 1 As shown, the imaging device of Embodiment 1 mainly includes a housing with a through hole (not shown), an optical lens 10 assembled within the housing, and an imaging element 19 for converting the optical image formed by the optical lens 10 into an electrical signal. The optical lens 10 mainly includes six lenses spaced apart from each other, specifically, from the object side to the image side, including: a first lens 11, a second lens 12, a third lens 13, an aperture 17, a fourth lens 14, a fifth lens 15, a sixth lens 16, and a filter 18. The aperture 17 is located near the object-side surface of the fourth lens 14.

[0044] The optical lens 10 of Embodiment 1 is configured to meet the parameters listed in Tables 1.1, 1.2 and 1.3.

[0045] Table 1.1 lists the basic parameters of the optical lens in Example 1, including the total effective focal length f, the relative aperture FNO, the maximum field of view FOV, the radius of curvature (in mm), the thickness (in mm), the refractive index and dispersion coefficient of the lens material, and the focal length (in mm). Surface numbers are numbered from the object side to the image side.

[0046] Table 1.2 shows the aspherical coefficients of each lens in Example 1. These coefficients all satisfy the aspherical formula (1) above.

[0047] Table 1.3 shows the values ​​of the conditions satisfied by the optical lens in Example 1.

[0048] Appendix Figure 2 The diagram shows the astigmatism and distortion curves of the optical lens in Embodiment 1.

[0049]

[0050]

[0051]

[0052] Example 2:

[0053] like Figure 3 As shown, the imaging device of Embodiment 2 mainly includes a housing with a through hole (not shown), an optical lens 20 assembled within the housing, and an imaging element 29 for converting the optical image formed by the optical lens 20 into an electrical signal. The optical lens 20 mainly includes six lenses spaced apart from each other, specifically, from the object side to the image side, including: a first lens 21, a second lens 22, a third lens 23, an aperture 27, a fourth lens 24, a fifth lens 25, a sixth lens 26, and a filter 28. The aperture 27 is located closer to the object-side surface of the fourth lens 24 than the third lens 23.

[0054] The optical lens 20 of Embodiment 2 is configured to meet the parameters listed in Tables 2.1, 2.2 and 2.3.

[0055] Table 2.1 lists the basic parameters of the optical lens in Example 2, including the total effective focal length f, the relative aperture FNO, the maximum field of view FOV, the radius of curvature (in mm), the thickness (in mm), the refractive index and dispersion coefficient of the lens material, and the focal length (in mm). The surface numbers are numbered from the object side to the image side.

[0056] Table 2.2 shows the aspherical coefficients of each lens in Example 2. These coefficients all satisfy the above aspherical formula (1).

[0057] Table 2.3 shows the values ​​of the conditions satisfied by the optical lens in Example 2.

[0058] Appendix Figure 4 The diagram shows the astigmatism and distortion curves of the optical lens in Embodiment 2.

[0059]

[0060]

[0061]

[0062] Example 3:

[0063] like Figure 5As shown, the imaging device of Embodiment 3 mainly includes a housing with a through hole (not shown), an optical lens 30 assembled within the housing, and an imaging element 39 for converting the optical image formed by the optical lens 30 into an electrical signal. The optical lens 30 mainly includes six lenses spaced apart from each other, specifically, from the object side to the image side, including: a first lens 31, a second lens 32, a third lens 33, an aperture 37, a fourth lens 34, a fifth lens 35, a sixth lens 36, and a filter 38. The aperture 37 is located closer to the object-side surface of the fourth lens 34 than the third lens 33.

[0064] The optical lens 30 of Embodiment 3 is configured to meet the parameters listed in Tables 3.1, 3.2 and 3.3.

[0065] Table 3.1 lists the basic parameters of the optical lens in Example 3, including the total effective focal length f, the relative aperture FNO, the maximum field of view FOV, the radius of curvature (in mm), the thickness (in mm), the refractive index and dispersion coefficient of the lens material, and the focal length (in mm). The surface numbers are numbered from the object side to the image side.

[0066] Table 3.2 shows the aspherical coefficients of each lens in Example 3. These coefficients all satisfy the above aspherical formula (1).

[0067] Table 3.3 shows the values ​​of the conditions satisfied by the optical lens in Example 3.

[0068] Appendix Figure 6 The diagram shows the astigmatism and distortion curves of the optical lens in Embodiment 3.

[0069]

[0070]

[0071]

[0072] Example 4:

[0073] like Figure 7 As shown, the imaging device of Embodiment 4 mainly includes a housing with a through hole (not shown), an optical lens 40 assembled within the housing, and an imaging element 49 for converting the optical image formed by the optical lens 40 into an electrical signal. The optical lens 40 mainly includes six lenses spaced apart from each other, specifically, from the object side to the image side, including: a first lens 41, a second lens 42, a third lens 43, an aperture 47, a fourth lens 44, a fifth lens 45, a sixth lens 46, and a filter 48. The aperture 47 is located near the object-side surface of the fourth lens 44.

[0074] The optical lens 40 of Embodiment 4 is configured to meet the parameters listed in Tables 4.1, 4.2 and 4.3.

[0075] Table 4.1 lists the basic parameters of the optical lens in Example 4, including the total effective focal length f, the relative aperture FNO, the maximum field of view FOV, the radius of curvature (in mm), the thickness (in mm), the refractive index and dispersion coefficient of the lens material, and the focal length (in mm). The surface numbers are numbered from the object side to the image side.

[0076] Table 4.2 shows the aspherical coefficients of each lens in Example 4. These coefficients all satisfy the aspherical formula (1) above.

[0077] Table 4.3 shows the values ​​of the conditions satisfied by the optical lens in Example 4.

[0078] Appendix Figure 8 The diagram shows the astigmatism and distortion curves of the optical lens in Embodiment 4.

[0079]

[0080]

[0081]

[0082] Example 5:

[0083] like Figure 9 As shown, the imaging device of Embodiment 5 mainly includes a housing with a through hole (not shown), an optical lens 50 assembled within the housing, and an imaging element 59 for converting the optical image formed by the optical lens 50 into an electrical signal. The optical lens 50 mainly includes six lenses spaced apart from each other, specifically, from the object side to the image side, including: a first lens 51, a second lens 52, a third lens 53, an aperture 57, a fourth lens 54, a fifth lens 55, a sixth lens 56, and a filter 58. The aperture 57 is located at the edge of the object-side surface of the fourth lens 54.

[0084] The optical lens 50 of Embodiment 5 is configured to meet the parameters listed in Tables 5.1, 5.2 and 5.3.

[0085] Table 5.1 lists the basic parameters of the optical lens in Example 5, including the total effective focal length f, the relative aperture FNO, the maximum field of view FOV, the radius of curvature (in mm), the thickness (in mm), the refractive index and dispersion coefficient of the lens material, and the focal length (in mm). The surface numbers are numbered from the object side to the image side.

[0086] Table 5.2 shows the aspherical coefficients of each lens in Example 5. These coefficients all satisfy the aspherical formula (1) above.

[0087] Table 5.3 shows the values ​​of the conditions satisfied by the optical lens in Example 5.

[0088] Appendix Figure 10 The diagram shows the astigmatism and distortion curves of the optical lens of Embodiment 5.

[0089]

[0090]

[0091]

[0092] In summary, Examples 1 to 5 respectively satisfy the relationships shown in Table 6 below.

[0093] Table 6 Comparison of optical lens parameters of the imaging devices in the five embodiments

[0094] In summary, the aforementioned optical lens employs a six-element lens structure. Through appropriate material selection and refractive power matching, under specific conditions, the entire optical lens possesses excellent light-gathering capabilities, satisfying imaging requirements while achieving a 360-degree imaging effect. Furthermore, it offers advantages such as good optical performance, excellent space utilization, and ease of lens processing and assembly.

[0095] Furthermore, the terms "first," "second," etc., are used only to distinguish one feature from another, and do not imply any limitation on the feature.

[0096] Although the description of the invention has been given in conjunction with the specific embodiments described above, it will be apparent to those skilled in the art that many substitutions, modifications, and variations can be made based on the foregoing. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. An optical lens comprising six lenses: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, wherein the first to sixth lenses are sequentially spaced along the optical axis from the object side to the image side; characterized in that: The first lens has negative refractive power, and its object side is convex near the optical axis, while its image side is concave near the optical axis. The second lens has negative refractive power, and its image-side surface is concave near the optical axis; The third lens has positive refractive power, and its object side is convex near the optical axis, while its image side is concave near the optical axis. The fourth lens has positive refractive power, and its object side is convex near the optical axis, and its image side is convex near the optical axis. The fifth lens has positive refractive power, and its object side is convex near the optical axis, and its image side is convex near the optical axis. The sixth lens has negative refractive power, and its object side is concave near the optical axis, and its image side is concave near the optical axis. The optical lens satisfies 194°≥FOV≥180°, 0.123≥f / OTTL≥0.110, 0.1≤CT4 / ΣCT≤0.3, 0.9≤|L4R1 / L4R2|≤3.101, where FOV is the maximum field of view of the optical lens, f is the total effective focal length of the optical lens, OTTL is the total optical length of the optical lens, CT4 is the thickness of the fourth lens on the optical axis, ΣCT is the sum of the thicknesses of the six lenses on the optical axis, L4R1 is the radius of curvature of the object side of the fourth lens, and L4R2 is the radius of curvature of the image side of the fourth lens. The optical lens further includes an aperture stop located between the third lens and the fourth lens, and a filter located on the image side of the sixth lens; the optical lens satisfies 1.9≤FNO≤2.0, where FNO is the relative aperture of the optical lens; The optical lens satisfies the following condition: 2≤f3 / f4≤5, where f3 is the focal length of the third lens and f4 is the focal length of the fourth lens.

2. The optical lens according to claim 1, characterized in that, The optical lens satisfies (CT1 / ET1)+(CT2 / ET2)≥0.7, where CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, ET1 is the edge thickness of the first lens, and ET2 is the edge thickness of the second lens.

3. The optical lens according to claim 1, characterized in that, The maximum F-theta distortion of the optical lens across the entire field of view is less than or equal to 10%.

4. The optical lens according to claim 1, characterized in that, The optical lens satisfies ATmax / CTmax≥0.6, where ATmax is the maximum distance between adjacent lenses on the optical axis, and CTmax is the maximum thickness of the lens with the largest thickness on the optical axis among the six lenses.

5. The optical lens according to claim 1, characterized in that, The object-side and image-side surfaces of the first and fourth lenses are both glass spherical surfaces, while the object-side and image-side surfaces of the second, third, fifth, and sixth lenses are plastic aspherical surfaces.

6. The optical lens according to claim 1, characterized in that, The optical lens satisfies L1D1 / f≤9.5, where L1D1 is the effective optical dimension of the object-side surface of the first lens.

7. An imaging device, characterized in that, It includes an optical lens as described in any one of claims 1-6 and an imaging element for converting an optical image formed by the optical lens into an electrical signal.

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