An optical lens

Abstract

This invention provides an optical lens comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object side to the image side. The first lens has negative optical power, with a convex object-side surface and a concave image-side surface. The second lens has negative optical power, with a concave object-side surface and a convex image-side surface. The third lens has positive optical power, with a convex object-side surface. The fourth lens has a convex object-side surface and concave image-side surfaces. The fifth lens has positive optical power, with both its object-side and image-side surfaces being convex. The sixth lens has negative optical power, with both its object-side and image-side surfaces being concave. The seventh lens has negative optical power, with a concave object-side surface and a convex image-side surface. This achieves small size, low cost, large target area, high pixel count, and high transmittance.

Description

Technical Field

[0001] This utility model relates to the field of lens technology, and in particular to an optical lens. Background Technology

[0002] In recent years, the photography industry has been pursuing high-quality images, and this trend is also true for conventional security lenses. High-quality lenses and high-resolution sensors are necessary conditions for achieving high-quality final images. However, after the pixel count of sensors has reached a certain limit, a large sensor surface has become a requirement for high-resolution sensors. Utility Model Content

[0003] This utility model provides an optical lens that features small size, low cost, large target area, high pixel count, and high transmittance.

[0004] This utility model embodiment provides an optical lens, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object side to the image side;

[0005] The first lens has negative optical power, the object side of the first lens is convex, and the image side of the first lens is concave.

[0006] The second lens has negative optical power, the object side of the second lens is concave, and the image side of the second lens is convex.

[0007] The third lens has positive optical power, and the object side of the third lens is convex.

[0008] The object-side surface of the fourth lens is convex, and the image-side surface of the fourth lens is concave.

[0009] The fifth lens has positive optical power, and both the object-side and image-side surfaces of the fifth lens are convex.

[0010] The sixth lens has negative optical power, and both the object-side and image-side surfaces of the sixth lens are concave.

[0011] The seventh lens has negative optical power, the object side of the seventh lens is concave, and the image side of the seventh lens is convex.

[0012] Optionally, the fourth lens is cemented to the fifth lens.

[0013] Optionally, it may also include an aperture stop located between the third lens and the fourth lens.

[0014] Optionally, at least four of the first to seventh lenses are plastic lenses, and at least two of the first to seventh lenses are glass lenses.

[0015] Optionally, the optical power of the first lens is The optical power of the second lens is The optical power of the third lens is The optical power of the fifth lens is The optical power of the sixth lens is The optical power of the seventh lens is The optical lens has an optical power of ,satisfy:

[0016] -0.486< <-0.304, -0.274< <-0.079, 0.261< <0.781, 1.094< <1.403, -1.159< <-0.541, -0.062< <-0.026.

[0017] Optionally, at least four of the first to seventh lenses have an Abbe number greater than 40.

[0018] Optionally, the Abbe number of the first lens is vd1, the Abbe number of the third lens is vd3, the Abbe number of the fifth lens is vd5, and the Abbe number of the seventh lens is vd7, satisfying:

[0019] 38.00 <vd1<62.00,38.00<vd3<62.00,37.00<vd5<69.00,38.00<vd7<62.00。

[0020] Optionally, the second lens has a refractive index of nd2, and the fourth lens has a refractive index of nd4, satisfying: 1.660 <nd2,1.660<nd4。

[0021] Optionally, the Abbe number of the sixth lens is vd6, satisfying: 17.50 <vd6<29.50。

[0022] Optionally, the total optical length of the optical lens is TTL, satisfying: TTL < 16.000 mm.

[0023] The optical lens provided in this embodiment employs seven lenses, from the first to the seventh. By setting the optical power and surface shape of the first to the seventh lenses, it achieves the characteristics of small size, low cost, large target area, high pixel count, and high transmittance. The optical power of the first, second, and third lenses is negative-negative-positive, while the optical power of the fifth, sixth, and seventh lenses is positive-negative-negative. The symmetrical distribution of optical power between the first three lenses and the last three lenses not only balances the aberrations of single lenses and optical lenses but also adjusts the overall optical length of the optical lenses, ultimately enabling the optical lens to meet the characteristics of small size, large target area, and high pixel count, allowing the small-sized optical lens to be compatible with a 1 / 2.7-inch target area. Attached Figure Description

[0024] Figure 1 This is a structural diagram of an optical lens according to Embodiment 1;

[0025] Figure 2 This is a chromatic aberration curve of an optical lens according to Embodiment 1.

[0026] Figure 3 This is a transverse chromatic aberration diagram of an optical lens according to Embodiment 1.

[0027] Figure 4 This is a structural diagram of an optical lens according to Embodiment 2;

[0028] Figure 5 This is a chromatic aberration curve of an optical lens according to Embodiment 2.

[0029] Figure 6 This is a transverse chromatic aberration diagram of an optical lens according to Embodiment 2;

[0030] Figure 7 This is a structural diagram of an optical lens according to Embodiment 3;

[0031] Figure 8 This is a chromatic aberration curve of an optical lens according to Embodiment 3;

[0032] Figure 9 This is a chromatic aberration diagram of an optical lens according to Embodiment 3. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0034] Example 1

[0035] Figure 1 This is a structural diagram of an optical lens according to Embodiment 1; see reference. Figure 1 The optical lens comprises a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, and a seventh lens 7 arranged sequentially along the optical axis from the object side to the image side. The first lens 1 has negative optical power, its object-side surface is convex, and its image-side surface is concave; the first lens 1 is a convex-concave lens. The second lens 2 has negative optical power, its object-side surface is concave, and its image-side surface is convex; the second lens 2 is a concave-convex lens. The third lens 3 has positive optical power, its object-side surface is convex; the image-side surface of the third lens 3 can be either convex or concave. The third lens 3 can be a biconvex lens or a convex-concave lens. The fourth lens 4 has a convex object-side surface, and both its image-side surfaces are concave; the fourth lens 4 is a convex-concave lens. The fifth lens 5 has positive optical power, and both its object-side and image-side surfaces are convex; the fifth lens 5 is a biconvex lens. Lens 6 has negative optical power, and both its object-side and image-side surfaces are concave; lens 6 is a biconcave lens. Lens 7 has negative optical power, its object-side surface is concave, and its image-side surface is convex; lens 7 is a concave-convex lens.

[0036] The optical lens provided in this embodiment employs seven lenses, from the first lens 1 to the seventh lens 7. By setting the optical power and surface shape of the first lens 1 to the seventh lens 7, it achieves the characteristics of small size, low cost, large target surface, high pixel count, and high transmittance. The optical power of the first lens 1, the second lens 2, and the third lens 3 are negative-negative-positive, respectively, while the optical power of the fifth lens 5, the sixth lens 6, and the seventh lens 7 are positive-negative-negative, respectively. The symmetrical optical power distribution of the first three lenses and the last three lenses not only balances the aberrations of single lenses and optical lenses but also adjusts the overall optical length of the optical lens, ultimately enabling the optical lens to meet the characteristics of small size, large target surface, and high pixel count, allowing the small-sized optical lens to be compatible with a 1 / 2.7-inch target surface.

[0037] Optical power refers to the reciprocal of the rectified focal length, used to characterize the ability of an optical lens or optical system to converge or diverge light. Since the optical power value in this application is relatively large, it is adopted... This is used to represent the magnitude of optical power.

[0038] Optionally, the fourth lens 4 and the fifth lens 5 are cemented together. The fourth lens 4 and the fifth lens 5 form a cemented lens.

[0039] Optionally, the optical lens also includes an aperture stop STO, located between the third lens 3 and the fourth lens 4. By placing the aperture stop STO between the third lens 3 and the fourth lens 4, the image quality of the off-axis field of view can be significantly improved. Simultaneously, a cemented lens (i.e., a cemented lens composed of the fourth lens 4 and the fifth lens 5) is placed near the aperture stop STO to reduce on-axis chromatic aberration. This ensures that chromatic aberration is well controlled from the on-axis field of view to the off-axis field of view. The cemented lens near the aperture stop STO also helps to further reduce the tolerance of the optical lens, enabling it to simultaneously meet the quality requirements of a large sensor size and high pixel count, as well as the tolerance requirements in the production process.

[0040] For example, the aperture of the object side of the fourth lens 4 defines the aperture stop STO.

[0041] Optionally, at least four of the first lens 1 to the seventh lens 7 are plastic lenses, and at least two of the first lens 1 to the seventh lens 7 are glass lenses. Using at least two glass lenses ensures high transmittance, while using at least four plastic lenses ensures low-cost operation in the optical lens manufacturing process.

[0042] For example, the plastic lens is a plastic aspherical lens, and the glass lens is a glass spherical lens. Plastic lenses have lower mass and greater adaptability in shape, allowing them to be manufactured into various complex shapes to reduce overall lens aberrations. The image quality of multiple glass spherical lenses can be achieved with a small number of plastic aspherical lenses, which is beneficial for achieving high resolution, low cost, and small size in optical lenses. Simultaneously, this optical lens also includes at least two glass lenses. Glass lenses have a wider range of refractive indices and Abbe numbers than plastic lenses, which can effectively optimize chromatic aberration and aperture, further contributing to high resolution and small size. Furthermore, the use of a glass-plastic hybrid material facilitates a heat-free design for the optical lens.

[0043] Optionally, the optical power of the first lens 1 is The optical power of the second lens 2 is The optical power of the third lens 3 is The optical power of the fifth lens 5 is The optical power of the sixth lens 6 is The optical power of the seventh lens 7 is The optical lens has an optical power of The condition is satisfied: -0.486 < <-0.304, -0.274< <-0.079, 0.261< <0.781, 1.094< <1.403, -1.159< <-0.541, -0.062< <-0.026. The reasonable optical power of the single lens and the symmetrical optical power distribution of the preceding three lenses and the following three lenses can not only balance the aberrations of the single lenses and the optical lens, but also adjust the total optical length of the optical lens, finally enabling the optical lens to satisfy the characteristics of small volume, large target surface and high pixel.

[0044] Optionally, the Abbe number of at least four of the first lens 1 to the seventh lens 7 is greater than 40. High transmittance is achieved by using a plurality of high Abbe number materials. A high Abbe number material means low dispersion. The optical lens comprises at least four lenses made of low dispersion materials. Low dispersion materials are generally crystal clear, having high and stable transmittance for light rays. The use of a certain amount of low dispersion materials helps the optical lens achieve the characteristic of high transmittance. Images presented by an optical lens with high transmittance have distinct colors, which can avoid the influence of color cast of the optical lens to a certain extent.

[0045] Optionally, let the Abbe number of the first lens 1 be vd1, the Abbe number of the third lens 3 be vd3, the Abbe number of the fifth lens 5 be vd5, and the Abbe number of the seventh lens 7 be vd7, which satisfies: 38.00 < vd1 < 62.00, 38.00 < vd3 < 62.00, 37.00 < vd5 < 69.00, 38.00 < vd7 < 62.00. The symmetrical lens design with Abbe number materials near the stop STO can well reduce the lateral chromatic aberration of the optical lens. It should be noted that the symmetrical lens design with Abbe number materials herein means that the selection ranges of Abbe number materials for the first lens 1, the third lens 3, the fifth lens 5 and the seventh lens 7 are close. After a certain Abbe number material value is selected, their Abbe numbers are all greater than 30, and they are not typical lenses made of low Abbe number materials.

[0046] Optionally, let the refractive index of the second lens 2 be nd2, and the refractive index of the fourth lens 4 be nd4, which satisfies: 1.660 < nd2, 1.660 < nd4. The second lens 2 and the fourth lens 4 are made of high refractive index materials, which maintain the optical power distribution of the entire optical lens to achieve a small volume. The high refractive index material of the second lens 2 can well balance the requirements of aberration and light aperture, and the refractive index material of the fourth lens 4 can well reduce the spherical aberration of the optical lens, which is beneficial for improving the on-axis image quality of the optical lens.

[0047] Further, let the Abbe number of the sixth lens 6 be vd6, which satisfies: 17.50 < vd6 < 29.50. Selecting a plastic aspheric lens material with a low Abbe number for the sixth lens 6 can well optimize the off-axis aberration of the optical lens. The combination of the above-mentioned refractive index and Abbe number materials is beneficial for the optical lens to achieve the characteristics of small volume, low cost, large target surface and high pixel.

[0048] Optionally, the total optical length of the optical lens is TTL, satisfying: TTL < 16.000 mm. This ultimately enables the optical lens to meet the characteristics of small size, large target surface, and high pixel count, allowing the small-sized optical lens to be compatible with a 1 / 2.7-inch target surface.

[0049] For example, the optical lens may further include a flat glass CG, which is located on the side of the seventh lens 7 away from the first lens 1 and on the side of the seventh lens 7 adjacent to the image plane IMA, to protect the photosensitive chip in the imaging sensor. The photosensitive chip is used to convert the light signals collected by the lens into electrical signals, thereby ensuring the imaging effect of the lens.

[0050] For example, an aspherical lens (including a plastic aspherical lens) satisfies the following formula:

[0051]

[0052] Where Z is the aspherical elevation, c is the fundamental curvature at the vertex, k is the conic section constant, and r is the radial coordinate perpendicular to the optical axis. For higher-order terms, For aspherical surfaces, the term is of higher order. Among them, The numbers are 2, 3, 4, 5, 6, 7, and 8 respectively.

[0053] Table 1. Design values ​​for an optical lens in Example 1.

[0054]

[0055] Table 1 shows one design value for the optical lens in Embodiment 1. The specific values ​​can be adjusted according to product requirements and are not intended to limit the embodiments of this utility model. The optical lens shown in Table 1 can be... Figure 1As shown. A lens generally consists of two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are assigned according to the surfaces of each lens. Surface number S1 represents the front surface (object side) of the first lens 1, surface number S2 represents the rear surface (image side) of the first lens 1, and so on, which will not be elaborated further here. The radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the object surface, with the center closer to the image surface; a negative value indicates that the surface bends towards the image surface, with the center closer to the object surface. "Infinite" indicates that the surface is flat, with an infinite radius of curvature, and the unit is mm. The values ​​in the thickness column represent the axial distance between the center of the current surface and the next surface, and the unit is mm. Because the different number of decimal places of each parameter value can cause focusing errors, the thickness corresponding to S15 is undetermined and no specific value is given. The value can be adjusted as needed to achieve a clear focus. The refractive index column represents the refractive index of the medium between the current surface and the next surface, representing the ability of the material between the current surface and the next surface to deflect light. The blank space in the refractive index column represents the refractive index of air, which is 1. The Abbe number represents the dispersion characteristics of light by the material between the current surface and the next surface; a blank space indicates the current location is air. The half-diameter refers to the radius of the lens's light-transmitting area (i.e., half the effective light-transmitting diameter), measured in mm.

[0056] Table 2 Aspherical coefficients of the optical lens in Example 1

[0057]

[0058] The "Face Number" column in Table 2 has the same meaning as the "Face Number" column in Table 1. In the various embodiments of this utility model, "E" represents a power base 10.

[0059] The optical lens in this embodiment meets the following parameters: focal length of 3.568mm, aperture of F2.3, field of view of 101.2°, and total optical length of 13.316mm.

[0060] In this embodiment, the object-side surface of the third lens 3 is convex; the image-side surface of the third lens 3 is also convex. The first lens 1, the third lens 3, the sixth lens 6, and the seventh lens 7 are plastic aspherical lenses, and the first lens 2, the fourth lens 4, and the fifth lens 5 are glass spherical lenses. The Abbe number of the first lens 1, the second lens 2, the third lens 3, the fifth lens 5, and the seventh lens 7 is greater than 40.

[0061] Figure 2 This is a chromatic aberration curve of an optical lens according to Embodiment 1; Reference Figure 2The vertical direction represents the normalization of the 0-field pupil plane, where 0 represents the pupil center, and the vertical vertex represents the pupil vertex; the horizontal direction represents the axial chromatic aberration of different wavelengths, in millimeters (mm). As shown in the figure, the axial chromatic aberration is within ±0.05mm, indicating that the optical lens has good chromatic aberration correction.

[0062] Figure 3 This is a transverse chromatic aberration diagram of an optical lens according to Embodiment 1; Reference Figure 3 The vertical direction represents the field of view angle, with 0 representing the field of view angle incident parallel to the optical axis, and the vertical vertex representing the maximum half-field of view angle. The horizontal direction represents the offset within the meridian range with 0.546μm as the reference, in micrometers (μm). The numbers on the curves in the figure represent the wavelengths represented by the curves, in micrometers (μm). As shown in the figure, the chromatic aberration along the vertical axis for each wavelength is within ±10μm, indicating that the optical lens has good chromatic aberration correction. As the angle increases, the chromatic aberrations along the vertical axis for each wavelength overlap, indicating that the optical lens has a certain degree of chromatic aberration correction for each field of view.

[0063] Example 2

[0064] Similarities to the above embodiments will not be repeated here.

[0065] Table 3 shows a design value for the optical lens in Example 2.

[0066]

[0067] Table 3 shows one design value for the optical lens in Embodiment 2. The specific values ​​can be adjusted according to product requirements and are not intended to limit the embodiments of this utility model. The optical lens shown in Table 3 can be... Figure 4 As shown.

[0068] Table 4 Aspherical coefficients of the optical lens in Example 2

[0069]

[0070] The meaning of the "Face Number" column in Table 4 is consistent with that in Table 3. In the various embodiments of this utility model, "E" represents a power base 10.

[0071] The optical lens of this embodiment meets the following parameters: focal length of 3.319mm, aperture of F2.3, field of view of 104.0°, and total optical length of 14.008mm.

[0072] In this embodiment, the object-side surface of the third lens 3 is convex, and the image-side surface of the third lens 3 is concave. The Abbe numbers of the first lens 1, the third lens 3, the fourth lens 4, the fifth lens 5, and the seventh lens 7 are greater than 40.

[0073] Figure 5This is a chromatic aberration curve of an optical lens according to Embodiment 2; Reference Figure 5 The vertical direction represents the normalization of the 0-field pupil plane, where 0 represents the pupil center, and the vertical vertex represents the pupil vertex; the horizontal direction represents the axial chromatic aberration of different wavelengths, in millimeters (mm). As shown in the figure, the axial chromatic aberration is within ±0.05mm, indicating that the optical lens has good chromatic aberration correction.

[0074] Figure 6 This is a transverse chromatic aberration diagram of an optical lens according to Embodiment 2; Reference Figure 6 The vertical direction represents the field of view angle, with 0 representing the field of view angle incident parallel to the optical axis, and the vertical vertex representing the maximum half-field of view angle. The horizontal direction represents the offset within the meridian range with 0.546μm as the reference, in micrometers (μm). The numbers on the curves in the figure represent the wavelengths represented by the curves, in micrometers (μm). As shown in the figure, the chromatic aberration along the vertical axis for each wavelength is within ±10μm, indicating that the optical lens has good chromatic aberration correction. As the angle increases, the chromatic aberrations along the vertical axis for each wavelength overlap, indicating that the optical lens has a certain degree of chromatic aberration correction for each field of view.

[0075] Example 3

[0076] Similarities to the above embodiments will not be repeated here.

[0077] Table 5 shows a design value for the optical lens in Example 3.

[0078]

[0079] Table 5 shows one design value for the optical lens in Embodiment 3. The specific values ​​can be adjusted according to product requirements and are not intended to limit the embodiments of this utility model. The optical lens shown in Table 5 can be... Figure 7 As shown.

[0080] Table 6 Aspherical coefficients of the optical lens in Example 3

[0081]

[0082] The meaning of the "Face Number" column in Table 6 is consistent with that in Table 5. In the various embodiments of this utility model, "E" represents a power base 10.

[0083] The optical lens in this embodiment meets the following parameters: focal length of 3.351mm, aperture of F2.3, field of view of 104.0°, and total optical length of 13.653mm.

[0084] In this embodiment, the object-side surface of the third lens 3 is convex, and the image-side surface of the third lens 3 is concave. The Abbe numbers of the first lens 1, the third lens 3, the fourth lens 4, and the fifth lens 5 are greater than 40.

[0085] Figure 8 This is a chromatic aberration curve of an optical lens according to Embodiment 3; Reference Figure 8 The vertical direction represents the normalization of the 0-field pupil plane, where 0 represents the pupil center, and the vertical vertex represents the pupil vertex; the horizontal direction represents the axial chromatic aberration of different wavelengths, in millimeters (mm). As shown in the figure, the axial chromatic aberration is within ±0.05mm, indicating that the optical lens has good chromatic aberration correction.

[0086] Figure 9 This is a transverse chromatic aberration diagram of an optical lens according to Embodiment 3; Reference Figure 9 The vertical direction represents the field of view angle, with 0 representing the field of view angle incident parallel to the optical axis, and the vertical vertex representing the maximum half-field of view angle. The horizontal direction represents the offset within the meridian range with 0.546μm as the reference, in micrometers (μm). The numbers on the curves in the figure represent the wavelengths represented by the curves, in micrometers (μm). As shown in the figure, the chromatic aberration along the vertical axis for each wavelength is within ±10μm, indicating that the optical lens has good chromatic aberration correction. As the angle increases, the chromatic aberrations along the vertical axis for each wavelength overlap, indicating that the optical lens has a certain degree of chromatic aberration correction for each field of view.

[0087] Table 7 Parameter Design Values ​​for Each Embodiment

[0088]

[0089] In summary, the fourth lens 4 has different positive and negative optical power settings in different embodiments. This utility model embodiment achieves high transmittance by employing multiple high Abbe material lenses and / or glass lenses, and large target area and high pixel count by using cemented lenses and / or symmetrical structures; it achieves small volume by employing a certain number of high refractive index materials and / or protecting the optical power distribution of the entire lens; and it utilizes a large number of plastic aspherical lenses to ensure low cost in the lens manufacturing process.

[0090] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An optical lens, characterized in that, It includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object side to the image side; The first lens has negative optical power, the object side of the first lens is convex, and the image side of the first lens is concave. The second lens has negative optical power, the object side of the second lens is concave, and the image side of the second lens is convex. The third lens has positive optical power, and the object side of the third lens is convex. The object-side surface of the fourth lens is convex, and the image-side surface of the fourth lens is concave. The fifth lens has positive optical power, and both the object-side and image-side surfaces of the fifth lens are convex. The sixth lens has negative optical power, and both the object-side and image-side surfaces of the sixth lens are concave. The seventh lens has negative optical power, the object side of the seventh lens is concave, and the image side of the seventh lens is convex.

2. The optical lens according to claim 1, characterized in that, The fourth lens is cemented to the fifth lens.

3. The optical lens according to claim 1, characterized in that, It also includes an aperture stop, which is located between the third lens and the fourth lens.

4. The optical lens according to claim 1, characterized in that, At least four of the first to the seventh lenses are plastic lenses, and at least two of the first to the seventh lenses are glass lenses.

5. The optical lens according to claim 1, characterized in that, The optical power of the first lens is The optical power of the second lens is The optical power of the third lens is The optical power of the fifth lens is The optical power of the sixth lens is The optical power of the seventh lens is The optical lens has an optical power of ,satisfy: ， ， ， ， ， 。 6. The optical lens according to claim 1, characterized in that, At least four of the first to seventh lenses have an Abbe number greater than 40.

7. The optical lens according to claim 6, characterized in that, The Abbe number of the first lens is vd1, the Abbe number of the third lens is vd3, the Abbe number of the fifth lens is vd5, and the Abbe number of the seventh lens is vd7, satisfying the following: ， ， ， 。 8. The optical lens according to claim 1, characterized in that, The second lens has a refractive index of nd2, and the fourth lens has a refractive index of nd4, satisfying the following: , .

9. The optical lens according to claim 8, characterized in that, The Abbe number of the sixth lens is vd6, which satisfies: .

10. The optical lens according to claim 1, characterized in that, The total optical length of the optical lens is TTL, satisfying: .

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