Aerial and underwater lens

Abstract

The application discloses a water-air dual-purpose lens, which comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens in sequence along an optical axis from an object side to an image side, the first lens has a negative refractive power, the object side is a plane, and the image side is a concave surface; the second lens has a negative refractive power, the object side is a concave surface, and the image side is a concave surface; the third lens has a positive refractive power, the object side is a convex surface, and the image side is a convex surface; the fourth lens has a positive refractive power, the object side is a convex surface, and the image side is a convex surface; the fifth lens has a negative refractive power, the object side is a concave surface, and the image side is a concave surface; the sixth lens has a positive refractive power, the object side is a plane or a concave surface, and the image side is a convex surface; the seventh lens has a positive refractive power, the object side is a convex surface, and the image side is a concave surface; wherein the fourth lens and the fifth lens are glued; the first lens is made of a material with a hardness of 680*10^7 Pa or above, and the first lens is coated with a hydrophobic film. The water-air dual-purpose lens has the advantages of low cost and high-definition water-air imaging.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and in particular to a lens that can be used both underwater and in the air. Background Technology

[0002] Existing lenses typically only provide high-definition imaging in one of two environments: air or underwater, and cannot be used in both simultaneously. Generally, the field of view and depth of field of a lens decrease significantly when used underwater. Underwater photography lenses usually use a flat glass or dome lens to waterproof the front, but this affects image quality and increases costs.

[0003] Some underwater and air-to-air lenses consist of many lenses, which results in excessive costs. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a low-cost underwater and air-to-air lens.

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

[0006] A water-and-air dual-purpose lens, which includes a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, a sixth lens and a seventh lens in sequence along an optical axis from the object side to the image side. Each of the first lens to the seventh lens includes an object side facing the object side and allowing imaging light to pass through, and an image side facing the image side and allowing imaging light to pass through.

[0007] The first lens has negative refractive power, with a planar object-side surface and a concave image-side surface;

[0008] The second lens has negative refractive power, and both the object-side and image-side surfaces are concave.

[0009] The third lens has positive refractive power, and the object side is convex, as is the image side;

[0010] The fourth lens has positive refractive power, and the object-side surface is convex, as is the image-side surface;

[0011] The fifth lens has negative refractive power, and the object side is concave, as is the image side;

[0012] The sixth lens has positive refractive power, and the object side is either flat or concave, while the image side is convex.

[0013] The seventh lens has positive refractive power, with a convex object-side surface and a concave image-side surface;

[0014] The image side of the fourth lens and the object side of the fifth lens are glued together.

[0015] The first lens is made of a material with a Knoop hardness of 680*10^7 Pa or higher, and the first lens is coated with a hydrophobic film.

[0016] The beneficial effects of this invention are as follows: It employs a 7-element spherical design, resulting in low cost, structural stability, strong practicality, high yield, and good mass production capabilities. The first lens is coated with a hydrophobic film, allowing direct contact with water without the need for a spherical dome or flat glass for front-end waterproofing. This reduces costs and mitigates issues such as reduced field of view, lower illumination, and aberration changes caused by flat glass or spherical domes, thus improving image quality. Furthermore, the first lens material has a Knoop hardness of over 680*10^7 Pa, ensuring excellent stability under deep-sea water pressure, enabling dual-use in water and air. Attached Figure Description

[0017] Figure 1 The diagram shown is a structural schematic of the underwater and air-to-air lens according to Embodiment 1 of the present invention;

[0018] Figure 2 The image shown is an MTF curve of the underwater dual-purpose lens of Embodiment 1 of the present invention when the operating environment is underwater and the spatial frequency is 200 lp / mm.

[0019] Figure 3 The image shown is an MTF curve of the underwater and air-to-air lens of Embodiment 1 of the present invention when the operating environment is air and the spatial frequency is 100 lp / mm.

[0020] Figure 4 The image shown is the RI diagram of the water-and-air dual-purpose lens of Embodiment 1 of the present invention.

[0021] Figure 5 The diagram shown is a structural schematic of the water-and-air dual-purpose lens of Embodiment 2 of the present invention;

[0022] Figure 6 The image shown is an MTF curve of the underwater dual-purpose lens of Embodiment 2 of the present invention when the operating environment is underwater and the spatial frequency is 200 lp / mm.

[0023] Figure 7 The image shown is an MTF curve of the underwater and air-to-air lens of Embodiment 2 of the present invention when used in air and with a spatial frequency of 100 lp / mm.

[0024] Figure 8 The image shown is the RI diagram of the water-and-air dual-purpose lens of Embodiment 2 of the present invention;

[0025] Figure 9 The diagram shown is a structural schematic of the water-and-air dual-purpose lens of Embodiment 3 of the present invention;

[0026] Figure 10The image shown is an MTF curve of the underwater dual-purpose lens of Embodiment 3 of the present invention when the operating environment is underwater and the spatial frequency is 200 lp / mm.

[0027] Figure 11 The image shown is the MTF curve of the underwater and air-to-air lens of Embodiment 3 of the present invention when the operating environment is air and the spatial frequency is 100 lp / mm.

[0028] Figure 12 The image shown is the RI diagram of the water-and-air dual-purpose lens of Embodiment 3 of the present invention.

[0029] Figure 13 The diagram shown is a structural schematic of the water-and-air dual-purpose lens of Embodiment 4 of the present invention;

[0030] Figure 14 The image shown is an MTF curve of the underwater dual-purpose lens of Embodiment 4 of the present invention when the operating environment is underwater and the spatial frequency is 200 lp / mm.

[0031] Figure 15 The image shown is the MTF curve of the underwater and air-to-air lens of Embodiment 4 of the present invention when the operating environment is air and the spatial frequency is 100 lp / mm.

[0032] Figure 16 The image shown is the RI diagram of the underwater and air-to-air lens of Embodiment 4 of the present invention. Detailed Implementation

[0033] To better understand the technical content, objectives, and effects of this invention, the following detailed description, in conjunction with specific embodiments and accompanying drawings, is provided. It should be noted that, unless otherwise specified, the embodiments and features of this invention can be combined with each other. Numerous specific details are set forth in the following description to provide a thorough understanding of this invention. The described embodiments are merely a part of, and not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0034] Please refer to Figure 1 , 5 As shown in Figures 9 and 13, the technical solution provided by this invention is as follows:

[0035] A water-and-air dual-purpose lens, which includes a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, a sixth lens and a seventh lens in sequence along an optical axis from the object side to the image side. Each of the first lens to the seventh lens includes an object side facing the object side and allowing imaging light to pass through, and an image side facing the image side and allowing imaging light to pass through.

[0036] The first lens has negative refractive power, with a planar object-side surface and a concave image-side surface;

[0037] The second lens has negative refractive power, and both the object-side and image-side surfaces are concave.

[0038] The third lens has positive refractive power, and the object side is convex, as is the image side;

[0039] The fourth lens has positive refractive power, and the object-side surface is convex, as is the image-side surface;

[0040] The fifth lens has negative refractive power, and the object side is concave, as is the image side;

[0041] The sixth lens has positive refractive power, and the object side is either flat or concave, while the image side is convex.

[0042] The seventh lens has positive refractive power, with a convex object-side surface and a concave image-side surface;

[0043] The image side of the fourth lens and the object side of the fifth lens are glued together.

[0044] The first lens is made of a material with a Knoop hardness of 680*10^7 Pa or higher, and the first lens is coated with a hydrophobic film.

[0045] Furthermore, the aforementioned dual-purpose underwater and air-to-air lens satisfies the following requirements:

[0046] Vd4 > 65, Vd5 < 25, and |Vd4 - Vd5| > 40, where Vd4 is the dispersion coefficient of the fourth lens and Vd5 is the dispersion coefficient of the fifth lens.

[0047] Combining high- and low-dispersion materials helps correct chromatic aberration and optimize image quality. Cemented composites can reduce tolerance sensitivity, while retaining some chromatic aberration to balance the optical system's overall chromatic aberration. They can also reduce tolerance sensitivity issues such as lens tilting / eccentricity that occur during assembly.

[0048] Furthermore, the optical power of the fourth lens is positive, and its dn / dt < -8×10E-6 / ℃, where dn / dt is the temperature coefficient of refractive index.

[0049] The fourth lens, with the aforementioned settings for optical power and refractive index temperature coefficient, can effectively reduce lens temperature drift under high and low temperature conditions, thus ensuring good resolution within a temperature range of -40℃ to 85℃.

[0050] Furthermore, the aforementioned dual-purpose underwater and air-to-air lens satisfies the following requirements:

[0051] The lens has a focal length of 2.36mm, an aperture of f / 2.8, an overall optical length of 22mm, a principal ray angle of 4.9°, and a maximum field of view of 175°. It is highly practical.

[0052] Furthermore, each lens surface is coated with a broadband anti-reflective coating. As a result, the reflectivity of the lens in the visible light spectral range is less than 0.4%, which can effectively reduce ghosting and improve the quality of the image.

[0053] Furthermore, it also includes a sensor, which is adapted to each lens, and the sensor has a size of 1 / 2.8″ and a pixel size of 2µm.

[0054] The underwater and air-to-air lens of the present invention will be described in detail below with reference to specific embodiments.

[0055] Example 1

[0056] like Figure 1 As shown, a water-and-air dual-purpose lens includes, in sequence along an optical axis from the object side to the image side, a first lens 1, a second lens 2, a third lens 3, an aperture, a fourth lens 4, a fifth lens 5, a sixth lens 6, and a seventh lens 7. Each of the first lens 1 to the seventh lens 7 includes an object side facing the object side and allowing imaging light to pass through, and an image side facing the image side and allowing imaging light to pass through.

[0057] The first lens 1 has negative refractive power, with a planar object-side surface and a concave image-side surface;

[0058] The second lens 2 has negative refractive power, and the object-side surface is concave, as is the image-side surface;

[0059] The third lens 3 has positive refractive power, and the object side is convex, as is the image side;

[0060] The fourth lens 4 has positive refractive power, and the object side is convex, as is the image side;

[0061] The fifth lens 5 has negative refractive power, and the object side is concave, as is the image side;

[0062] The sixth lens 6 has positive refractive power, and the object side is either flat or concave, while the image side is convex.

[0063] The seventh lens 7 has positive refractive power, with a convex object side and a concave image side;

[0064] The image side of the fourth lens 4 and the object side of the fifth lens 5 are glued together.

[0065] The first lens 1 is made of a material with a Knoop hardness of 680*10^7 Pa or higher, and the first lens 1 is coated with a hydrophobic film. The first lens 1 to the seventh lens 7 are made of glass, and each lens surface is coated with a broadband anti-reflective coating (BBAR film).

[0066] The underwater / air-use lens meets the following conditions:

[0067] Vd4 > 65, Vd5 < 25, and |Vd4 - Vd5| > 40, where Vd4 is the dispersion coefficient of the fourth lens 4 and Vd5 is the dispersion coefficient of the fifth lens 5.

[0068] The fourth lens has a positive optical power and its dn / dt < -8×10E-6 / ℃, where dn / dt is the temperature coefficient of refractive index.

[0069] The underwater / air-use lens is used with a sensor that has a size of 1 / 2.8″ and a pixel size of 2µm.

[0070] Detailed optical data for this embodiment are shown in Table 1.

[0071]

[0072] Table 1

[0073] The underwater / airborne lens of this embodiment has a focal length of 2.36mm, an aperture of F2.8, a total optical length (TTL) of 22mm, and a principal ray angle (CRA) of 4.5°. The MTF curve for underwater use at a spatial frequency of 200 lp / mm is shown below. Figure 2 As shown, the MTF curve for use in air at a spatial frequency of 100 lp / mm is as follows. Figure 3 As shown, the RI diagram is as follows Figure 4 As shown.

[0074] Example 2

[0075] like Figure 5 As shown, the surface concavity and convexity of each lens in this embodiment are roughly the same as those in Embodiment 1, with the only difference being the optical parameters of each lens. Detailed optical data are shown in Table 2.

[0076]

[0077] Table 2

[0078] The underwater / airborne lens of this embodiment has a focal length of 2.36mm, an aperture of F2.8, a total optical length (TTL) of 22mm, and a principal ray angle (CRA) of 4.9°. The MTF curve for underwater use at a spatial frequency of 200 lp / mm is shown below. Figure 6As shown, the MTF curve for use in air at a spatial frequency of 100 lp / mm is as follows. Figure 7 As shown, the RI diagram is as follows Figure 8 As shown.

[0079] Example 3

[0080] like Figure 9 As shown, the surface concavity and convexity of each lens in this embodiment are roughly the same as those in Embodiment 1, with the only difference being the optical parameters of each lens. Detailed optical data are shown in Table 3.

[0081]

[0082] Table 3

[0083] The underwater / airborne lens of this embodiment has a focal length of 2.36mm, an aperture of F2.8, a total optical length (TTL) of 22mm, and a principal ray angle (CRA) of 4.5°. The MTF curve for underwater use at a spatial frequency of 200 lp / mm is shown below. Figure 10 As shown, the MTF curve for use in air at a spatial frequency of 100 lp / mm is as follows. Figure 11 As shown, the RI diagram is as follows Figure 12 As shown.

[0084] Example 4

[0085] like Figure 13 As shown, the surface concavity and convexity of each lens in this embodiment are roughly the same as those in Embodiment 1, except that the optical parameters of each lens are different. Detailed optical data are shown in Table 4.

[0086]

[0087] Table 4

[0088] The underwater / airborne lens of this embodiment has a focal length of 2.36mm, an aperture of F2.8, a total optical length (TTL) of 22mm, and a principal ray angle (CRA) of 4.7°. The MTF curve for underwater use at a spatial frequency of 200 lp / mm is shown below. Figure 14 As shown, the MTF curve for use in air at a spatial frequency of 100 lp / mm is as follows. Figure 15 As shown, the RI diagram is as follows Figure 16 As shown.

[0089] As can be seen from the underwater MTF curves of the above embodiments, at a spatial frequency of 200 lp / mm, the center MTF value is greater than 0.55 and the edge MTF value is greater than 0.3, indicating high resolution and good imaging effect for underwater use.

[0090] As can be seen from the air MTF curves of the above embodiments, at a spatial frequency of 100 lp / mm, the center MTF value is greater than 0.76 and the edge MTF value is greater than 0.3, and the imaging effect in the air is also very good.

[0091] As can be seen from the RI diagrams of the above embodiments, the lens still has more than 70% illuminance in a 160° field of view, with high relative illuminance values ​​at the edges, and good image brightness even in low-light environments.

[0092] In summary, the underwater / air-use lens of this invention features a 7-element all-glass spherical design, resulting in low cost. The first lens is designed to directly contact the water, eliminating the need for a protective cover and allowing direct use in seawater, thus achieving dual-use capability. It also exhibits good MTF in both underwater and air environments, enabling high-definition imaging in both conditions. The lens has a focal length of 2.36mm, an aperture of F2.8, a total optical length (TTL) of 22mm, a principal ray angle (CRA) of up to 4.9°, and a maximum field of view of 175°. It is suitable for a wide working distance (0.2m-inf) and is highly practical.

[0093] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Therefore, any modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An aerial and underwater lens, characterized by, Along an optical axis from the object side to the image side, the lens comprises a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The optical element with optical power in the lens is composed of the first lens to the seventh lens. Each of the first lens to the seventh lens includes an object side facing the object side and allowing imaging light to pass through, and an image side facing the image side and allowing imaging light to pass through. The first lens has negative refractive power, with a planar object-side surface and a concave image-side surface; The second lens has negative refractive power, and both the object-side and image-side surfaces are concave. The third lens has positive refractive power, and the object side is convex, as is the image side; The fourth lens has positive refractive power, and the object-side surface is convex, as is the image-side surface; The fifth lens has negative refractive power, and the object side is concave, as is the image side; The sixth lens has positive refractive power, and the object side is either flat or concave, while the image side is convex. The seventh lens has positive refractive power, with a convex object-side surface and a concave image-side surface; The image side of the fourth lens and the object side of the fifth lens are glued together. The first lens is made of a material with a Knoop hardness of 680*10^7 Pa or higher, and the first lens is coated with a hydrophobic film.

2. The dual-purpose lens for water and air according to claim 1, wherein The underwater / air-use lens satisfies the following requirements: Vd4 > 65, Vd5 < 25, and |Vd4 - Vd5| > 40, where Vd4 is the dispersion coefficient of the fourth lens and Vd5 is the dispersion coefficient of the fifth lens.

3. The dual-purpose lens according to claim 1, wherein The fourth lens has a positive optical power and its dn / dt < -8×10E-6 / ℃, where dn / dt is the temperature coefficient of refractive index.

4. The dual-purpose lens according to claim 1, wherein The underwater / air-use lens satisfies the following requirements: The lens has a focal length of 2.36mm, an aperture of f / 2.8, an optical length of 22mm, a principal ray angle of 4.9°, and a maximum field of view of 175°.

5. The dual-purpose lens according to claim 1, wherein Each lens surface is coated with a broadband anti-reflective coating.

6. The underwater / air-use lens according to claim 1, characterized in that, It also includes a sensor that is adapted to each lens, the sensor having a size of 1 / 2.8″ and a pixel size of 2µm.

Images