Optical lens

Abstract

The application provides an optical lens, which comprises six lenses in sequence along an optical axis from an object side to an imaging surface, and the six lenses comprise: a first lens with positive refractive power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; a second lens with negative refractive power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; a third lens with negative refractive power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; a fourth lens with negative refractive power, the image side surface of the fourth lens is a concave surface; a fifth lens with positive refractive power, the object side surface and the image side surface of the fifth lens are both convex surfaces; and a sixth lens with positive refractive power, the object side surface of the sixth lens is a convex surface; wherein the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: -16.2 < R5 / R6 < -3.2. The optical lens provided by the application adopts six lenses with specific refractive power, and through specific surface shape matching and reasonable refractive power distribution, the lens has one or more advantages of high pixels, high imaging quality, miniaturization and the like.

Description

Technical Field

[0001] This invention relates to the technical field of imaging lenses, and in particular to an optical lens. Background Technology

[0002] In the field of intelligent manufacturing, industrial lenses are widely used due to their advantages such as high precision, high speed, and high efficiency. They can record key parameters and data in the production process at any time, thereby improving production efficiency and product quality. It is foreseeable that the market for industrial lenses will experience explosive growth in the future, and their application in intelligent manufacturing will become even more widespread. With the continuous upgrading of industrial lenses, the requirements for them in intelligent manufacturing will become increasingly stringent, with high resolution, miniaturization, and excellent imaging effects becoming the main development trends for industrial lenses.

[0003] However, existing industrial lenses still have many shortcomings, such as being too long, bulky, and heavy, which makes them difficult to install; the increased field of view of the lenses makes it difficult to correct aberrations in the system and reduces image quality; and they are unable to meet market demands.

[0004] Therefore, it is necessary to develop an optical lens with one or more advantages such as high pixel count, high image quality, and miniaturization to better meet the high demands of the market. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide an optical lens that has one or more advantages such as high pixel count, high image quality, and miniaturization.

[0006] The technical solution adopted in this invention is as follows:

[0007] An optical lens comprises six lenses, arranged sequentially along the optical axis from the object side to the imaging plane:

[0008] The first lens with positive optical power has a convex object side and a concave image side.

[0009] A second lens with negative optical power has a convex object side and a concave image side.

[0010] A third lens with negative optical power has a convex object side and a concave image side.

[0011] The fourth lens has negative optical power and its image-side surface is concave.

[0012] The fifth lens with positive optical power has convex surfaces on both its object side and image side.

[0013] The sixth lens has positive optical power and its object side is convex.

[0014] Among them, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -16.2 < R5 / R6 < -3.2.

[0015] Further preferably, the total optical length TTL of the optical lens and the effective focal length f satisfy: 2 < TTL / f < 2.5.

[0016] Further preferably, the total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle satisfy: 2.7 < TTL / IH < 3.4.

[0017] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.5 < f3 / f < -0.8.

[0018] Further preferably, the focal length f5 of the fifth lens, the focal length f6 of the sixth lens, and the distance CT56 between the fifth lens and the sixth lens on the optical axis satisfy: 5 < (f5 + f6) / CT56 < 12.2.

[0019] Further preferably, the combined focal length F123 of the first lens, the second lens, and the third lens and the combined focal length F456 of the fourth lens, the fifth lens, and the sixth lens satisfy: -2.8 < F123 / F456 < -1.8.

[0020] Further preferably, the effective focal length f3 of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -1.0 < R6 / f3 < -0.4

[0021] Further preferably, the edge thickness ET4 of the fourth lens and the central thickness CT4 of the fourth lens satisfy: 0.9 < ET4 / CT4 < 1.3.

[0022] Further preferably, the clear aperture semi-diameter d5 of the object side surface of the third lens and the sagittal height sag5 of the clear aperture of the object side surface of the third lens satisfy: 10 < d5 / sag5 < 14; the object side surface of the fourth lens is concave, and the image side surface of the sixth lens is convex.

[0023] Further preferably, the second lens, the third lens, and the sixth lens are aspherical lenses; the optical lens includes at least one glass lens and one plastic lens; the object side surface of the fourth lens is convex, and the image side surface of the sixth lens is convex or concave.

[0024] The optical lens provided by this invention uses six lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as high pixel count, high imaging quality, and miniaturization. Attached Figure Description

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0026] Figure 1 This is a schematic diagram of the optical lens structure in Embodiment 1 of the present invention.

[0027] Figure 2 This is the F-Tanθ distortion curve of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 5 This is a relative illumination curve of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 6 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0032] Figure 7 This is the F-Tanθ distortion curve of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 8 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 9 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 10 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 11 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0037] Figure 12 This is the F-Tanθ distortion curve of the optical lens in Embodiment 3 of the present invention.

[0038] Figure 13 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0039] Figure 14 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0040] Figure 15 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0041] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0042] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0044] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0045] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, 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-side surface of the lens.

[0046] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0047] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0049] The optical lens provided in this embodiment of the invention consists of six lenses, which are arranged sequentially along the optical axis from the object side to the imaging plane as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens.

[0050] In some embodiments, the first lens may have positive optical power, with a convex object-side surface and a concave image-side surface. The second lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The third lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The fourth lens may have negative optical power, with a concave image-side surface. The fifth lens may have positive optical power, with both its object-side and image-side surfaces being convex. The sixth lens may have positive optical power, with a convex object-side surface.

[0051] More specifically, the object-side surface of the fourth lens is concave, and the image-side surface of the sixth lens is convex. Alternatively, the object-side surface of the fourth lens is convex, and the image-side surface of the sixth lens is either convex or concave.

[0052] In some embodiments, the optical lens may further include an aperture, which may be located between the third lens and the fourth lens. It can be understood that the aperture is used to limit the amount of incident light to change the brightness of the image. Additionally, when the aperture is located between the third lens and the fourth lens, the aperture can reasonably distribute the functions of the first lens to the sixth lens. For example, the first lens, the second lens, and the third lens can be used to receive light to a greater extent, and the fourth lens to the sixth lens can be used to correct aberrations. At this time, the number of lenses for receiving light and the number of lenses for correcting aberrations in the optical lens of this embodiment are matched, which is beneficial to balancing the structure of the entire optical system. Furthermore, when the aperture is located between the third lens and the fourth lens, it is convenient to correct the aperture aberration.

[0053] In some embodiments, the optical lens may further include a filter and a protective glass, which may be sequentially arranged along the optical axis between the sixth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass plays a role in protecting the optical lens, which can improve the impact resistance and scratch resistance of the optical lens, and has almost no impact on the imaging quality of the optical lens.

[0054] In some embodiments, the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: -16.2 < R5 / R6 < -3.2. By satisfying the above conditional formula, the spherical aberration can be corrected, the imaging quality can be optimized, and the imaging quality can be improved by reasonably setting the surface shape of the third lens.

[0055] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f satisfy: 2 < TTL / f < 2.5. By satisfying the above conditional formula, it is beneficial to achieve miniaturization of the optical lens.

[0056] In some embodiments, the total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle satisfy: 2.7 < TTL / IH < 3.4. By satisfying the above conditional formula, the requirements for the image height and size of the optical lens can be balanced, which is beneficial to limiting the total length of the lens and better achieving large target surface imaging of the lens.

[0057] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.5 < f3 / f < -0.8. By satisfying the above conditional formula, the third lens bears an appropriate negative refractive power, which can increase the field angle and improve the imaging quality.

[0058] In some embodiments, the focal length f5 of the fifth lens, the focal length f6 of the sixth lens, and the spacing distance CT56 of the fifth lens and the sixth lens on the optical axis satisfy: 5 < (f5 + f6) / CT56 < 12.2. Satisfying the above conditional expression enables the optical lens to have better imaging capabilities while also having good thermal stability.

[0059] In some embodiments, the combined focal length F123 of the first lens, the second lens, and the third lens and the combined focal length F456 of the fourth lens, the fifth lens, and the sixth lens satisfy: -2.8 < F123 / F456 < -1.8. Satisfying the above conditional expression optimizes the imaging quality and improves the imaging performance by reasonably distributing the proportion of the focal lengths before and after the aperture.

[0060] In some embodiments, the effective focal length f3 of the third lens and the image-side curvature radius R6 of the third lens satisfy: -1.0 < R6 / f3 < -0.4. Satisfying the above conditional expression is conducive to better adjusting various chromatic aberrations of the system and improving the resolution by reasonably setting the surface shape of the third lens.

[0061] In some embodiments, the edge thickness ET4 of the fourth lens and the central thickness CT4 of the fourth lens satisfy: 0.9 < ET4 / CT4 < 1.3. Satisfying the above conditional expression makes the shape of the fourth lens transition smoothly and reduces the processing difficulty.

[0062] In some embodiments, the clear aperture semi-diameter d5 of the object side of the third lens and the sagittal height sag5 of the clear aperture of the object side of the third lens satisfy: 10 < d5 / sag5 < 14; satisfying the above conditional expression is conducive to controlling the trend of the marginal field light rays and highlighting the detailed information of the central field of the optical lens.

[0063] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens can be spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the second lens, the third lens, and the sixth lens of the present invention adopt aspherical lenses, and the first lens, the fourth lens, and the fifth lens adopt spherical lenses.

[0064] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. More specifically, the optical lens provided by the present invention includes at least one glass lens and one plastic lens. The combination of six lenses, with glass and plastic mixed, can have good thermal stability on the premise of meeting high pixels, and can reduce costs.

[0065] In some embodiments, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: 0.1 < f3 / f4 < 0.9. By satisfying the above conditional formula and reasonably distributing the focal length ratio of the third lens and the fourth lens, it is possible to avoid excessive deflection of light when passing through the system, reduce the difficulty of aberration correction, and at the same time better correct the field curvature and distortion of the lens, ensuring that the field curvature and distortion of the lens are controlled at a relatively small level and achieving high-pixel imaging of the system.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -1.0 < f2 / f < -0.5. By satisfying the above conditional formula, the second lens bears an appropriate negative refractive power, reducing the difficulty of correcting distortion and chromatic aberration for the rear-end lens.

[0067] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -5.5 < f4 / f < -1.5. By satisfying the above conditional formula, the fourth lens has an appropriate negative refractive power, reducing distortion and improving the imaging quality of the optical lens.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.3 < f5 / f < 0.9. By satisfying the above conditional formula, the fifth lens has an appropriate positive refractive power, improving the light converging ability, balancing aberrations, and improving the imaging quality.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.2 < f6 / f < 2.4. By satisfying the above conditional formula, the sixth lens has an appropriate positive refractive power, which is beneficial to suppressing the angle of incidence of the marginal field on the imaging surface.

[0070] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -8.6 < f4 / f5 < -3.2. By satisfying the above conditional formula, it is beneficial to balance the aberrations generated by the front-end lens and improve the imaging quality of the optical lens.

[0071] In some embodiments, the central thickness CT1 of the first lens and the central thickness CT2 of the second lens satisfy: 2.3 < CT1 / CT2 < 5.2. By satisfying the above conditional formula, through reasonable setting of the thicknesses of the first lens and the second lens, it is beneficial to adjust the light distribution, making the light transition relatively gentle when passing through the lens, which is beneficial to the control of lens distortion and enables the lens to have less distortion.

[0072] In some embodiments, the clear aperture radius d6 of the image side of the third lens and the sagittal height sag6 of the clear aperture of the image side of the third lens satisfy: 4 < d6 / sag6 < 7; by satisfying the above conditional formula, it is beneficial to control the trend of the light rays in the marginal field of view and highlight the detailed information of the central field of view of the optical lens.

[0073] In some embodiments, the optical lens satisfies the conditional formula: 25 mm < TTL < 28 mm, 11 mm < f < 13 mm, 8 mm < IH < 10 mm, where TTL represents the total optical length of the optical lens, f represents the effective focal length of the optical lens, and IH represents the image height corresponding to the maximum field of view angle of the optical lens. By satisfying the above conditions, it shows that the optical lens provided by the embodiments of the present invention at least has the characteristics of a larger target surface and miniaturization.

[0074] In each embodiment of the present invention, when the lens is an aspherical lens, the surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0075]

[0076] where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the conic coefficient, and B, C, D, E, F, G, H are the surface coefficients of the fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order respectively.

[0077] The present invention will be further described in multiple embodiments below. In each embodiment, the thicknesses, radii of curvature, and material selections of the respective lenses in the optical lens are somewhat different. For specific differences, refer to the parameter tables of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent replacement methods and are all included in the protection scope of the present invention.

[0078] Embodiment 1

[0079] Please refer to Figure 1The figure shows a schematic diagram of the structure of the optical lens provided in Embodiment 1 of the present invention. The optical lens includes, in sequence along the optical axis from the object side to the imaging plane: a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a filter G1, and a protective glass G2.

[0080] The first lens L1 has positive optical power, its object side S1 is convex, and its image side S2 is concave.

[0081] The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave.

[0082] The third lens L3 has negative optical power, and its object side S5 and image side S6 are both convex surfaces.

[0083] Aperture ST;

[0084] The fourth lens L4 has negative optical power, and both its object-side surface S7 and image-side surface S8 are concave.

[0085] The fifth lens L5 has positive optical power, and both its object-side surface S9 and image-side surface S10 are concave.

[0086] The sixth lens L6 has positive optical power, and both its object-side surface S11 and image-side surface S12 are convex.

[0087] The object-side surface S13 and the image-side surface S14 of filter G1 are both planar.

[0088] The object side S15 and the image side S16 of the protective glass G2 are both flat.

[0089] The imaging plane S17 is a plane.

[0090] The first lens L1, the fourth lens L4, and the fifth lens L5 are glass spherical lenses, while the second lens L2, the third lens L3, and the sixth lens L6 are plastic aspherical lenses.

[0091] The relevant parameters of each lens in the optical lens of Example 1 are shown in Table 1-1.

[0092] Table 1-1

[0093]

[0094] The surface profile parameters of the aspherical lens in Example 1 are shown in Table 1-2.

[0095] Table 1-2

[0096]

[0097]

[0098] In this embodiment, the F-Tanθ distortion curve, MTF curve, transverse chromatic aberration curve, and relative illuminance curve of the optical lens are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown.

[0099] Figure 2 The F-Tanθ distortion curve of Example 1 is shown, which represents the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents the F-Tanθ distortion value (unit: %), and the vertical axis represents the field of view (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within -2% to 0, and the image compression in the edge angle region is relatively smooth, effectively improving the sharpness of the unfolded image.

[0100] Figure 3 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in various fields of view. The horizontal axis represents the frequency range (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this example is above 0.4 throughout the entire field of view. Within the range of 0–160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0101] Figure 4 The diagram shows the transverse chromatic aberration curves for Example 1, representing the chromatic aberration of each wavelength relative to the center wavelength (0.546 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the figure, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2 μm, indicating that the optical lens can excellently correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0102] Figure 5 The relative illumination curves for Example 1 are shown, representing the relative illumination values ​​at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half-field angle, indicating that the optical lens has good relative illumination.

[0103] Example 2

[0104] Please see Figure 6The figure shows a schematic diagram of the optical lens provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S7 of the fourth lens L4 is convex, the image side surface S12 of the sixth lens L6 is concave, and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0105] The relevant parameters of each lens in the optical lens of Example 2 are shown in Table 2-1.

[0106] Table 2-1

[0107]

[0108]

[0109] The surface profile parameters of the aspherical lens in Example 2 are shown in Table 2-2.

[0110] Table 2-2

[0111]

[0112] In this embodiment, the F-Tanθ distortion curve, MTF curve, transverse chromatic aberration curve, and relative illuminance curve of the optical lens are respectively as follows: Figure 7 , Figure 8 , Figure 9 , Figure 10 As shown. From Figure 7 As can be seen, the F-Tanθ distortion of the optical lens is controlled within -2% to 0, and the image compression in the edge angle region is relatively smooth, effectively improving the sharpness of the unfolded image. From Figure 8 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. Within the range of 0–160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies. Figure 9 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2μm, indicating that the optical lens can excellently correct chromatic aberration at the edges of the field of view and the second-order spectrum of the entire image plane. From Figure 10 As can be seen, the relative illumination value of the optical lens is still greater than 70% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0113] Example 3

[0114] Please see Figure 11The figure shows a schematic diagram of the optical lens provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S7 of the fourth lens L4 is a convex surface; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0115] The relevant parameters of each lens in the optical lens of Example 3 are shown in Table 3-1.

[0116] Table 3-1

[0117]

[0118] The surface profile parameters of the aspherical lens in Example 3 are shown in Table 3-2.

[0119] Table 3-2

[0120]

[0121]

[0122] In this embodiment, the F-Tanθ distortion curve, MTF curve, transverse chromatic aberration curve, and relative illuminance curve of the optical lens are respectively as follows: Figure 12 , Figure 13 , Figure 14 , Figure 15 As shown. From Figure 12 As can be seen, the F-Tanθ distortion of the optical lens is controlled within -2% to 0, and the image compression in the edge angle region is relatively smooth, effectively improving the sharpness of the unfolded image. From Figure 13 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. Within the range of 0–160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies. Figure 14 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2.5μm, indicating that this optical lens can excellently correct chromatic aberration at the edges of the field of view and the second-order spectrum of the entire image plane. From Figure 15 As can be seen, the relative illumination value of the optical lens is still greater than 75% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0123] Please refer to Table 4 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value FNO, true image height IH corresponding to the maximum field of view, principal ray incident angle CRA, and maximum field of view FOV, as well as the values ​​corresponding to each conditional expression in each embodiment.

[0124] Table 4

[0125]

[0126]

[0127] In summary, the optical lens provided by the present invention uses six lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as high pixel count, high imaging quality, and miniaturization.

[0128] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0129] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens comprising six lenses, characterized in that, It successively includes from the object side to the imaging surface along the optical axis: A first lens with positive optical power, whose object side is convex and whose image side is concave; A second lens with negative optical power, whose object side is convex and whose image side is concave; A third lens with negative optical power, whose object side is convex and whose image side is concave; A fourth lens with negative optical power, whose image side is concave; A fifth lens with positive optical power, whose object side and image side are both convex; A sixth lens with positive optical power, whose object side is convex; Wherein, the curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: -16.2 < R5 / R6 < -3.2; The overall optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle satisfy: 2.7 < TTL / IH < 3.

4.

2. The optical lens according to claim 1, characterized in that, The overall optical length TTL of the optical lens and the effective focal length f satisfy: 2 < TTL / f < 2.

5.

3. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.2 < f6 / f < 2.

4.

4. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.5 < f3 / f < -0.

8.

5. The optical lens according to claim 1, characterized in that, The focal length f5 of the fifth lens, the focal length f6 of the sixth lens, and the interval distance CT56 of the fifth lens and the sixth lens on the optical axis satisfy: 5 < (f5 + f6) / CT56 < 12.

2.

6. The optical lens according to claim 1, characterized in that, The combined focal length F123 of the first lens, the second lens, and the third lens and the combined focal length F456 of the fourth lens, the fifth lens, and the sixth lens satisfy: -2.8 < F123 / F456 < -1.

8.

7. The optical lens according to claim 1, characterized in that, The effective focal length f3 of the third lens and the curvature radius R6 of the image side of the third lens satisfy: -1.0 < R6 / f3 < -0.

4.

8. The optical lens according to claim 1, characterized in that, The edge thickness ET4 of the fourth lens and the central thickness CT4 of the fourth lens satisfy: 0.9 < ET4 / CT4 < 1.

3.

9. The optical lens according to claim 1, characterized in that, The clear aperture semi-diameter d5 of the object side of the third lens and the sagittal height sag5 of the clear aperture of the object side of the third lens satisfy: 10 < d5 / sag5 < 14; the object side of the fourth lens is concave, and the image side of the sixth lens is convex.

10. The optical lens according to claim 1, characterized in that, The second lens, the third lens, and the sixth lens are aspherical lenses; the optical lens includes at least one glass lens and one plastic lens; the object side of the fourth lens is convex, and the image side of the sixth lens is convex or concave.

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