Small long-focus optical system

Abstract

The invention discloses a small long-focus optical system, and belongs to the technical field of optical lenses. Comprising a first lens with positive focal power, a diaphragm, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power and a seventh lens with positive focal power which are sequentially arranged along the direction of an optical axis, the first lens with the positive focal power, the eighth lens with the negative focal power, the ninth lens with the positive focal power and the tenth lens with the negative focal power are arranged in a reasonably set value range. The small size, the long focal length and the large aperture are realized, the wide spectral response is realized, the cost is reduced, and the imaging quality is improved.

Description

Technical Field

[0001] This invention belongs to the field of optical lens technology, and specifically relates to a small telephoto optical system. Background Technology

[0002] In recent years, the application of imaging detection devices in security monitoring, field reconnaissance, intelligent monitoring, and spectral sensing has been continuously expanding. In particular, the technical demand for long-distance low-light observation and wide-spectrum sensing has continued to grow, which has placed higher demands on the performance of optical lenses that are compatible with them. For example, as the spectral response band continues to widen and the receiving area continues to increase, more target information can be obtained. Telephoto lenses can clearly capture distant targets and achieve long-distance shooting, which has led to the continuous development of telephoto lenses towards features such as long focal length, full-spectrum response, miniaturization, and high imaging quality.

[0003] However, traditional telephoto lenses struggle to balance magnification, light-gathering efficiency with large apertures, wide-spectrum aberration correction, and lightweight design. Either their optical performance is insufficient, directly impacting observation or sensing accuracy, or they employ more complex optical structures, such as combinations of eleven or more aspherical lenses, to ensure optical performance. This results in high manufacturing costs, increased size, and an unavoidable sacrifice in spectral response. In particular, the aperture numbers of traditional telephoto lenses are generally above f / 2.0, further limiting their widespread application in numerous fields. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by proposing a small long-focal-length optical system with small size, long focal length, large aperture, wide spectral response of 435nm-960nm, improved edge resolution capability, clear and sharp image, high contrast, low ghosting level, and good portability.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention proposes a small long-focal-length optical system, comprising a first lens with positive optical power, an aperture stop, a second lens with positive optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with negative optical power, a ninth lens with positive optical power, and a tenth lens with negative optical power, arranged sequentially along the optical axis, and satisfying the following conditions:

[0007]

[0008] in, The total optical length of a small telephoto optical system, in mm; The focal length of a small telephoto optical system, in mm; This refers to the aperture number of a small telephoto optical system.

[0009] Preferably, the compact telephoto optical system also satisfies the following conditions:

[0010]

[0011] in, The effective focal length of the first lens. The combined effective focal length of the second and third lenses. The combined effective focal length of the seventh and eighth lenses is in mm.

[0012] Preferably, the compact telephoto optical system also satisfies the following conditions:

[0013]

[0014] in, The thickness is measured in mm from the center of the image side of the eighth lens to the object side of the ninth lens.

[0015] Preferably, the compact telephoto optical system also satisfies the following conditions:

[0016]

[0017] in, Let be the radius of curvature of the object-side surface of the seventh lens. Let be the radius of curvature of the image-side surface of the eighth lens. The radius of curvature of the image-side surface of the tenth lens is in mm.

[0018] Preferably, the compact telephoto optical system also satisfies the following conditions:

[0019]

[0020] in, Let be the Abbe number of the first lens. The Abbe number of the third lens. Let be the Abbe number of the fourth lens.

[0021] Preferably, the compact telephoto optical system also satisfies the following conditions:

[0022] 1.5≤ ≤1.75; .

[0023] Preferably, the second and third lenses are cemented lenses, the fifth and sixth lenses are cemented lenses, the seventh and eighth lenses are cemented lenses, and the ninth and tenth lenses are cemented lenses.

[0024] Preferably, the compact telephoto optical system also satisfies the following conditions:

[0025] ; ;

[0026] ; ;

[0027] in, The effective focal length of the first lens. The combined effective focal length of the second and third lenses. The effective focal length of the fourth lens. The combined effective focal length of the seventh and eighth lenses. The combined effective focal length of the ninth and tenth lenses is in mm.

[0028] Preferably, the compact telephoto optical system also satisfies the following conditions:

[0029]

[0030] in, The center thickness of the first lens, The thickness of the eighth lens is shown in mm.

[0031] Preferably, the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens and tenth lens are all glass spherical lenses.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] This compact long-focal-length optical system employs a ten-lens architecture and, through optimized optical parameter settings, achieves a small size, long focal length, and large aperture while maintaining a wide spectral response of 435nm-960nm. It also enhances edge resolution, ensuring sharp and clear images with high contrast, low ghosting levels, good portability, and low cost. Specifically, the materials used in the first, third, and fourth lenses ensure a good match between positive and negative lenses, while cementing tolerance-sensitive lenses to reduce local sensitivity, significantly minimizing chromatic and spherical aberration across the wide spectrum, ensuring minimal infrared defocus and low risk of short-wave purple fringing. The optimized curvature radii of the seventh, eighth, and tenth lenses result in low ghosting levels, ensuring image purity. Furthermore, the preferred all-glass lens architecture provides more stable performance. It can be matched with a 1 / 1.8” chip, resulting in good image quality and a long focal length. It has a diameter of 49.0mm or more, an aperture number of 1.75 or less, and a total optical length of 55mm or less. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the small telephoto optical system of Embodiment 1 of the present invention;

[0035] Figure 2 The longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the small long-focal-length optical system of Embodiment 1 of the present invention are shown below.

[0036] Figure 3 This is a schematic diagram of the structure of the small telephoto optical system of Embodiment 2 of the present invention;

[0037] Figure 4 The longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the small long-focal-length optical system of Embodiment 2 of the present invention are shown below.

[0038] Figure 5 This is a schematic diagram of the structure of the small telephoto optical system of Embodiment 3 of the present invention;

[0039] Figure 6 The longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the small long-focal-length optical system of Embodiment 3 of the present invention are shown below.

[0040] Figure 7 This is a schematic diagram of the structure of the small telephoto optical system in Embodiment 4 of the present invention;

[0041] Figure 8 The images show the longitudinal spherical aberration, astigmatism, and distortion of the small long-focal-length optical system in Embodiment 4 of the present invention.

[0042] Explanation of reference numerals in the attached diagram: L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; L7, seventh lens; L8, eighth lens; L9, ninth lens; L10, tenth lens; STO, aperture stop; CG, protective glass; IMA, image plane. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application.

[0045] like Figure 1 , Figure 3 , Figure 5 , Figure 7 As shown, a small telephoto optical system includes a first lens L1 with positive optical power, an aperture stop STO, a second lens L2 with positive optical power, a third lens L3 with negative optical power, a fourth lens L4 with positive optical power, a fifth lens L5 with positive optical power, a sixth lens L6 with negative optical power, a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with positive optical power, and a tenth lens L10 with negative optical power, arranged sequentially along the optical axis, and satisfying the following condition:

[0046]

[0047] in, The total optical length of a small telephoto optical system, in mm; The focal length of a small telephoto optical system, in mm; This refers to the aperture number of a small telephoto optical system.

[0048] Specifically, the first lens L1 has positive optical power, which can quickly compress long-distance light rays into a funnel shape, reducing the aperture of subsequent lenses and facilitating chip size matching. An aperture stop STO is placed between the first lens L1 and the second lens L2, limiting the aperture of the first lens L1 and helping to compress the angle of incidence. The second lens L2, with positive optical power, and the third lens, with negative optical power, work together to quickly reduce chromatic aberration and spherical aberration in the optical system, reducing the difficulty of chromatic aberration compensation in subsequent lenses. The fourth lens L4, with positive optical power, preferably has a high Abbe number, making it suitable for glass materials with large abnormal dispersion, used to further compensate for remaining axial chromatic aberration. The fifth lens L5, with positive optical power, is preferably set with a high refractive index to reduce surface curvature, significantly reducing tolerance sensitivity and improving assemblability. The sixth lens L6, with negative optical power, combined with the fifth lens L5, can smoothly connect the refracted light rays of the fifth lens L5, avoiding large deflection angles that lead to poor tolerance characteristics. The combination of the seventh lens L7 (positive optical power) and the eighth lens L8 (negative optical power) can quickly compress light rays, bringing the light intensity down to match the image plane size. This facilitates the matching of the final lens group (ninth lens L9 and tenth lens L10) with the chip. The combination of the ninth lens L9 (positive optical power) and the tenth lens L10 (negative optical power) compensates for field curvature in both the inner and outer fields of view, smoothly elevates light rays, and lowers the angle of incidence of light rays onto the image plane, resulting in better chip matching and helping to reduce overall sensitivity.

[0049] Specifically, If the above conditions are met, the telephoto lens has strong overall compactness and large aperture characteristics, can detect distant low-light environments, and has a wide range of applications; if the upper limit is exceeded, the total length of the telephoto lens is large or the aperture number is large, and the miniaturization characteristics or aperture improvement are not obvious; if the lower limit is exceeded, the total length of the telephoto lens is small, the internal space is compressed too much, which will greatly increase the processing cost and assembly cost.

[0050] In one embodiment, the small telephoto optical system also satisfies the following condition:

[0051]

[0052] in, The effective focal length of the first lens L1 is... The combined effective focal length of the second lens L2 and the third lens L3. The combined effective focal length of the seventh lens L7 and the eighth lens L8 is in mm.

[0053] Specifically, If the above conditions are met, the first lens L1 can provide a reasonable contribution to the overall optical power, avoiding excessive or insufficient contribution that would lead to unreasonable imaging state and assembly characteristics of the optical system. Exceeding the upper limit, the proportion of optical power of the first lens L1 decreases, failing to fully utilize the lens's light-gathering capacity, resulting in insufficient optical power at the position of the first lens L1, requiring more lenses to compensate for spherical aberration; exceeding the lower limit, the proportion of optical power of the first lens L1 increases, leading to greater curvature and larger lens assembly eccentricity and tilt tolerances, failing to meet mass production assembly requirements.

[0054] If the above conditions are met, the combined effective focal length of the second lens L2 and the third lens L3 is within a reasonable range, reducing interference with descending light. The opposite signs of the optical power generated by the second lens L2 and the third lens L3 create a positive-negative power combination, which helps reduce chromatic aberration, forming a complementary relationship, reducing spherical aberration and broadband chromatic aberration, and evenly distributing overall tolerance sensitivity. If this range is exceeded, the combined effective focal length of the second lens L2 and the third lens L3 deviates too much from the defined range, weakening the chromatic aberration compensation effect and easily leading to severe eccentricity tolerance in this cemented lens, which is detrimental to actual assembly.

[0055] If the above conditions are met, and the seventh lens L7 and the eighth lens L8 are located in the middle of the optical system, at a position where light refraction is significant, reasonable constraints on the optical power can ensure good overall optical performance and tolerance. If the combined effective focal length of the seventh lens L7 and the eighth lens L8 is within a reasonable range, the thickness and the combination of positive and negative optical powers of the seventh lens L7 and the eighth lens L8 can achieve a smooth descent of light, avoiding the problem of large light refraction at the interface. The image side of the eighth lens L8 can also serve as a support surface to ensure a small assembly tilt on the object side of the eighth lens L8. If this range is exceeded, the combined effective focal length of the seventh lens L7 and the eighth lens L8 is unreasonable, and the optical power is prone to excessive concentration, increasing the eccentricity sensitivity at this location and reducing product yield.

[0056] In one embodiment, the small telephoto optical system also satisfies the following condition:

[0057]

[0058] in, The thickness is measured in mm, from the image-side surface of the eighth lens L8 to the object-side surface of the ninth lens L9.

[0059] Specifically, If the above conditions are met, the spatial gap between the image side of the eighth lens L8 and the object side of the ninth lens L9 is within a reasonable range. This ensures that the thickness of other lenses is reasonable and that the gap is sufficient to accommodate the lens barrel step, allowing for redundant space in lens material selection and thickness control. This helps reduce costs and improve product resolution. If the upper limit is exceeded, the internal space is excessively compressed, which is not conducive to material selection (such as glass) and chromatic aberration control, and brings too many difficulties to stray light suppression. If the lower limit is exceeded, the internal space utilization is insufficient, and the overall lens miniaturization characteristics are insufficient.

[0060] In one embodiment, the small telephoto optical system also satisfies the following condition:

[0061]

[0062] in, Let be the radius of curvature of the object-side surface of the seventh lens L7. Let be the radius of curvature of the image-side surface of the eighth lens L8. The radius of curvature of the image-side surface of the tenth lens L10 is in mm.

[0063] Specifically, If the above conditions are met, the ratio of the radius of curvature of the object side of the seventh lens L7 to the radius of curvature of the image side of the tenth lens L10 is within a reasonable range. This maintains the proportion of the optical power of the seventh lens L7 in the entire optical system while avoiding the risk of increasing flat ghost images due to the reverse sign (sign reversal) of the radius of curvature of the image side of the tenth lens L10. This ensures a smooth transition of the surface shape of the tenth lens L10, and both processability and ghost image performance are well guaranteed. If the ratio exceeds the range, the radius of curvature of the object side of the seventh lens L7 and the radius of curvature of the image side of the tenth lens L10 will be mismatched. This can easily cause a secondary reflection on the object side of the seventh lens L7 after the first reflection on the image side of the tenth lens L10, forming a high-energy ghost point on the image plane IMA, which seriously affects the image quality.

[0064] If the above conditions are met, the ratio of the curvature radius of the image-side surface of the eighth lens L8 to that of the tenth lens L10 is appropriate, maintaining their concave-convex relationship while limiting their sizes. This allows for controllable lens curvature and further restricts secondary reflection ghost images from the image-side surfaces of both lenses, while preventing excessive bending due to excessively small curvature radii. If the ratio exceeds this range, it becomes unreasonable, potentially causing a secondary reflection from the image-side surface of the eighth lens L8 after the primary reflection from the image-side surface of the tenth lens L10, resulting in a high-energy ghost image near the IMA of the image plane, severely impacting imaging performance.

[0065] In one embodiment, the small telephoto optical system also satisfies the following condition:

[0066]

[0067] in, Let L1 be the Abbe number. The Abbe number of the third lens L3. Let L4 be the Abbe number of the fourth lens.

[0068] Specifically, To meet the above conditions, the Abbe numbers of the first lens L1, the third lens L3, and the fourth lens L4 must be within a reasonable range. This ensures that all three lenses can use high Abbe number materials, even HZPK or HFK series materials, to fully utilize the anomalous dispersion characteristics of the materials. Combined with positive and negative optical power matching and cemented lens combinations, this rapidly reduces on-axis chromatic aberration and spherical aberration in telephoto lenses, while compensating for broad-spectrum chromatic aberration from 435nm to 940nm, achieving minimal infrared defocus and excellent purple fringing performance. Exceeding this range can easily lead to difficulties in compensating for broad-spectrum chromatic aberration and spherical aberration, increasing design complexity, reducing aberration compensation effectiveness, and affecting overall image quality.

[0069] In one embodiment, the small telephoto optical system also satisfies the following condition:

[0070] 1.5≤ ≤1.75; .

[0071] In one embodiment, the second lens L2 and the third lens L3 are cemented lenses, the image planes of the fifth lens L5 and the sixth lens L6 are cemented lenses, the image planes of the seventh lens L7 and the eighth lens L8 are cemented lenses, and the image planes of the ninth lens L9 and the tenth lens L10 are cemented lenses.

[0072] Specifically, the second lens L2 and the third lens form a cemented lens, which, through the matching of high Abbe numbers and special materials (such as the TK series and TF series), can quickly reduce chromatic aberration and spherical aberration in the optical system, reducing the difficulty of subsequent lens chromatic aberration compensation. The sixth lens L6 and the fifth lens L5 form a cemented lens, which can smoothly connect light rays and avoid large deflection angles after separation, resulting in poor tolerance characteristics. The seventh lens L7 and the eighth lens L8 form a cemented lens, which can quickly compress light rays, suppressing the light beam height to match the image plane size, facilitating chip matching. The ninth lens L9 and the tenth lens L10 form a cemented lens, which can compensate for field curvature in the inner and outer fields of view, smoothly raise the light beam, and lower the incident angle of the light beam to the image plane, which can better match the chip and help reduce overall sensitivity.

[0073] In one embodiment, the small telephoto optical system also satisfies the following condition:

[0074] ; ;

[0075] ; ;

[0076] in, The effective focal length of the first lens L1 is... The combined effective focal length of the second lens L2 and the third lens L3. The effective focal length of the fourth lens L4. The combined effective focal length of the seventh lens L7 and the eighth lens L8. The effective focal length of the combination of the ninth lens L9 and the tenth lens L10 is in mm. Meeting the above range ensures good aberration balance, lower assembly process precision requirements, and good image resolution.

[0077] In one embodiment, the small telephoto optical system also satisfies the following condition:

[0078]

[0079] in, The center thickness of the first lens L1 The values ​​represent the center thickness of the eighth lens L8, all in mm. Meeting the above range indicates that the center and edge thicknesses of the first lens L1 are appropriate and have good machinability. The center thickness of the eighth lens L8 is suitable and meets the impact requirements of the overall optical system.

[0080] In one embodiment, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, and the tenth lens L10 are all glass spherical lenses.

[0081] Among them, the all-glass spherical lens architecture makes the working performance more stable and facilitates the reduction of processing costs.

[0082] For ease of understanding, the following detailed embodiments are provided. The reference wavelength for the effective focal length, Abbe number, and refractive index in each embodiment is 546 nm.

[0083] Example 1:

[0084] like Figure 1 As shown, the compact telephoto optical system of this embodiment includes a first lens L1, an aperture stop STO, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and a protective glass CG arranged sequentially along the optical axis. The second lens L2 and the third lens L3 form a cemented doublet lens; the fourth lens L4, the fifth lens L5, and the sixth lens L6 form a cemented triplet lens; the seventh lens L7 and the eighth lens L8 form a cemented doublet lens; and the ninth lens L9 and the tenth lens L10 form a cemented doublet lens. All lenses are glass spherical lenses. This compact telephoto optical system satisfies... =50mm, =1.596, =54.9mm, , , , , , , It can achieve features such as telephoto, large aperture, and miniaturization, and can still maintain high resolution under mixed light conditions of visible light, 850nm, 940nm and 435nm-960nm.

[0085] Specifically, the optical parameters of the small telephoto optical system in this embodiment are shown in Table 1.

[0086] Table 1

[0087]

[0088] As shown in Table 1, surface number S0 represents the object plane, and surface numbers S1, S3, S4, S6, S7, S8, S10, S11, S13, S14, and S16 represent the object-side surfaces of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, and the protective glass CG, respectively. Surface numbers S2, S4, S5, S7, S8, S9, S11, S12, S14, S15, and S17 represent the image-side surfaces of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, and the protective glass CG, respectively. The cemented surface of the cemented lens is considered as one surface. Surface number STO represents the aperture stop, and surface number S18 represents the image plane IMA. Thickness is the axial distance, which is the distance along the optical axis of the lens.

[0089] Figure 2 This document presents the longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the compact long-focal-length optical system in this embodiment. The longitudinal spherical aberration diagram (LONGITUDINAL SPHERICAL ABER.) represents the deviation of the convergence point of light rays of different wavelengths after passing through the lens. The vertical axis of the LONGITUDINAL SPHERICAL ABER. represents the normalized pupil coordinates (from the pupil center to the pupil edge), and the horizontal axis represents the distance (in mm) from the image plane to the intersection of the ray and the optical axis. The LONGITUDINAL SPHERICAL ABER. shows that the deviation of the convergence point of light rays of different wavelengths in this embodiment tends to be consistent and is all within 0.05 mm, effectively suppressing blur spots or chromatic aberration in the image. In the astigmatism diagram (ASTIGMATIC FIELD CURVES), the S-curve represents the sagittal field curvature at a wavelength of 546 nm, and the T-curve represents the meridional field curvature at a wavelength of 546 nm. As shown in the astigmatism diagram, the field curvature in this embodiment is all within 0.1 mm, and the field curvature and astigmatism of each field of view are well corrected, with clear imaging at both the center and edges of the field of view. The distortion diagram indicates that the optical distortion is all within 2.0%, with minimal image deformation caused by the main beam, indicating excellent imaging quality of the optical system. In summary, the longitudinal spherical aberration, field curvature, and distortion of this optical system are well controlled, resulting in good imaging quality.

[0090] Example 2:

[0091] like Figure 3As shown, the compact telephoto optical system of this embodiment includes a first lens L1, a second lens L2, an aperture stop STO, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and a protective glass CG arranged sequentially along the optical axis. The second lens L2 and the third lens L3 form a cemented doublet; the fifth lens L5 and the sixth lens L6 form a cemented doublet; the seventh lens L7 and the eighth lens L8 form a cemented doublet; and the ninth lens L9 and the tenth lens L10 form a cemented doublet. All lenses are glass spherical lenses. This compact telephoto optical system satisfies... =51.5mm, =1.576, TTL=54.9mm, , , , , , , It can achieve features such as telephoto, large aperture, and miniaturization, and can still maintain high resolution under mixed light conditions of visible light, 850nm, 940nm and 435nm-960nm.

[0092] Specifically, the optical parameters of the small telephoto optical system in this embodiment are shown in Table 2.

[0093] Table 2

[0094]

[0095] As shown in Table 2, surface number S0 represents the object surface, and surface numbers S1, S3, S4, S6, S8, S9, S11, S12, S14, S15, and S17 represent the object surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, and the protective glass CG, respectively. S7, S9, S10, S12, S13, S15, S16, and S18 represent the image-side surfaces of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, and the protective glass CG, respectively. The cemented surface of the cemented lens is considered as one surface. The surface number STO indicates the aperture stop, and the surface number S19 indicates the image plane IMA.

[0096] Figure 4This document presents the longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the compact long-focal-length optical system in this embodiment. The longitudinal spherical aberration diagram (LONGITUDINAL SPHERICAL ABER.) represents the deviation of the convergence point of light rays of different wavelengths after passing through the lens. The vertical axis of the LONGITUDINAL SPHERICAL ABER. represents the normalized pupil coordinates from the pupil center to the pupil edge, and the horizontal axis represents the distance (in mm) from the image plane to the intersection of the ray and the optical axis. The LONGITUDINAL SPHERICAL ABER. shows that the deviation of the convergence point of light rays of different wavelengths in this embodiment tends to be consistent and is all within 0.1 mm, effectively suppressing blur spots or chromatic aberration in the image. In the astigmatism diagram (ASTIGMATIC FIELD CURVES), the S-curve represents the sagittal field curvature at a wavelength of 546 nm, and the T-curve represents the meridional field curvature at a wavelength of 546 nm. As shown in the astigmatism diagram, the field curvature in this embodiment is all within 0.1 mm, and the field curvature and astigmatism of each field of view are well corrected, with clear imaging at both the center and edges of the field of view. The distortion diagram indicates that the optical distortion is all within 2.0%, with minimal image deformation caused by the main beam, indicating excellent imaging quality of the optical system. In summary, the longitudinal spherical aberration, field curvature, and distortion of this optical system are well controlled, resulting in good imaging quality.

[0097] Example 3:

[0098] like Figure 5 As shown, the compact telephoto optical system of this embodiment includes a first lens L1, a second lens L2, an aperture stop STO, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and a protective glass CG arranged sequentially along the optical axis. The second lens L2 and the third lens L3 form a cemented doublet; the fifth lens L5 and the sixth lens L6 form a cemented doublet; the seventh lens L7 and the eighth lens L8 form a cemented doublet; and the ninth lens L9 and the tenth lens L10 form a cemented doublet. All lenses are glass spherical lenses. This compact telephoto optical system satisfies... =53.3mm, =1.606, =54.9mm, , , , , , , It can achieve features such as telephoto, large aperture, and miniaturization, and can still maintain high resolution under mixed light conditions of visible light, 850nm, 940nm and 435nm-960nm.

[0099] Specifically, the optical parameters of the small telephoto optical system in this embodiment are shown in Table 3.

[0100] Table 3

[0101]

[0102] As shown in Table 3, surface number S0 represents the object surface, and surface numbers S1, S3, S4, S6, S8, S9, S11, S12, S14, S15, and S17 represent the object surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, and the protective glass CG, respectively. S7, S9, S10, S12, S13, S15, S16, and S18 represent the image-side surfaces of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, and the protective glass CG, respectively. The cemented surface of the cemented lens is considered as one surface. The surface number STO indicates the aperture stop, and the surface number S19 indicates the image plane IMA.

[0103] Figure 6 This document presents the longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the compact long-focal-length optical system in this embodiment. The longitudinal spherical aberration diagram (LONGITUDINAL SPHERICAL ABER.) represents the deviation of the convergence focal point of light rays of different wavelengths after passing through the lens. The vertical axis of the LONGITUDINAL SPHERICAL ABER. represents the normalized pupil coordinates (from the pupil center to the pupil edge), and the horizontal axis represents the distance (in mm) from the image plane to the intersection of the ray and the optical axis. The LONGITUDINAL SPHERICAL ABER. shows that the deviation of the convergence focal point of light rays of different wavelengths in this embodiment tends to be consistent and is within 0.1m, effectively suppressing blur spots or chromatic aberration in the image. In the astigmatism diagram (ASTIGMATIC FIELD CURVES), the S-curve represents the sagittal field curvature at a wavelength of 546nm, and the T-curve represents the meridional field curvature at a wavelength of 546nm. As shown in the astigmatism diagram, the field curvature in this embodiment is within 0.1m, and both field curvature and astigmatism in each field of view are well corrected, with clear imaging at both the center and edges of the field of view. The distortion diagram indicates that optical distortion is within 2.0%, with minimal image deformation caused by the main beam, indicating excellent imaging quality of the optical system. In summary, the longitudinal spherical aberration, field curvature, and distortion of this optical system are well controlled, resulting in good imaging quality.

[0104] Example 4:

[0105] like Figure 7As shown, the compact telephoto optical system of this embodiment includes a first lens L1, an aperture stop STO, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and a protective glass CG arranged sequentially along the optical axis. The second lens L2 and the third lens L3 form a cemented doublet lens; the fourth lens L4, the fifth lens L5, and the sixth lens L6 form a cemented triplet lens; the seventh lens L7 and the eighth lens L8 form a cemented doublet lens; and the ninth lens L9 and the tenth lens L10 form a cemented doublet lens. All lenses are glass spherical lenses. This compact telephoto optical system satisfies... =52mm, =1.546, =54.9mm, , , , , , , It can achieve features such as telephoto, large aperture, and miniaturization, and can still maintain high resolution under mixed light conditions of visible light, 850nm, 940nm and 435nm-960nm.

[0106] Table 4

[0107]

[0108] As shown in Table 4, surface number S0 represents the object plane, and surface numbers S1, S3, S4, S6, S7, S8, S10, S11, S13, S14, and S16 represent the object-side surfaces of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, and the protective glass CG, respectively. Surface numbers S2, S4, S5, S7, S8, S9, S11, S12, S14, S15, and S17 represent the image-side surfaces of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, and the protective glass CG, respectively. The cemented surface of the cemented lens is considered as one surface. Surface number STO represents the aperture stop, and surface number S18 represents the image plane IMA.

[0109] Figure 8This document presents the longitudinal spherical aberration diagram, astigmatism diagram, and distortion diagram of the compact long-focal-length optical system in this embodiment. The longitudinal spherical aberration diagram (LONGITUDINAL SPHERICAL ABER.) represents the deviation of the convergence focal point of light rays of different wavelengths after passing through the lens. The vertical axis of the LONGITUDINAL SPHERICAL ABER. represents the normalized pupil coordinates (from the pupil center to the pupil edge), and the horizontal axis represents the distance (in mm) from the image plane to the intersection of the ray and the optical axis. The LONGITUDINAL SPHERICAL ABER. shows that the deviation of the convergence focal point of light rays of different wavelengths in this embodiment tends to be consistent and is within 0.1m, effectively suppressing blur spots or chromatic aberration in the image. In the astigmatism diagram (ASTIGMATIC FIELD CURVES), the S-curve represents the sagittal field curvature at a wavelength of 546nm, and the T-curve represents the meridional field curvature at a wavelength of 546nm. As shown in the astigmatism diagram, the field curvature in this embodiment is within 0.1m, and both field curvature and astigmatism in each field of view are well corrected, with clear imaging at both the center and edges of the field of view. The distortion diagram indicates that optical distortion is within 2.0%, with minimal image deformation caused by the main beam, indicating excellent imaging quality of the optical system. In summary, the longitudinal spherical aberration, field curvature, and distortion of this optical system are well controlled, resulting in good imaging quality.

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] The embodiments described above are merely specific and detailed examples of the embodiments described in this application, and should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A small telephoto optical system, characterized in that: It includes a first lens (L1) with positive optical power, an aperture stop (STO), a second lens (L2) with positive optical power, a third lens (L3) with negative optical power, a fourth lens (L4) with positive optical power, a fifth lens (L5) with positive optical power, a sixth lens (L6) with negative optical power, a seventh lens (L7) with positive optical power, an eighth lens (L8) with negative optical power, a ninth lens (L9) with positive optical power, and a tenth lens (L10) with negative optical power, arranged sequentially along the optical axis, and satisfying the following condition: in, The total optical length of the small telephoto optical system is expressed in mm. The focal length of the small telephoto optical system is in mm. The aperture number of the small telephoto optical system is given.

2. The compact telephoto optical system as described in claim 1, characterized in that: The small telephoto optical system also meets the following conditions: in, The effective focal length of the first lens (L1) is... The combined effective focal length of the second lens (L2) and the third lens (L3) is... The combined effective focal length of the seventh lens (L7) and the eighth lens (L8) is in mm.

3. The compact telephoto optical system as described in claim 1, characterized in that: The small telephoto optical system also meets the following conditions: in, The thickness is the center thickness from the image side of the eighth lens (L8) to the object side of the ninth lens (L9), in mm.

4. The compact telephoto optical system as described in claim 1, characterized in that: The small telephoto optical system also meets the following conditions: in, Let be the radius of curvature of the object-side surface of the seventh lens (L7). The radius of curvature of the image-side surface of the eighth lens (L8) is given. The radius of curvature of the image-side surface of the tenth lens (L10) is in mm.

5. The compact telephoto optical system as described in claim 1, characterized in that: The small telephoto optical system also meets the following conditions: in, The Abbe number of the first lens (L1) is... The Abbe number of the third lens (L3) is... The Abbe number of the fourth lens (L4).

6. The compact telephoto optical system as described in claim 1, characterized in that: The small telephoto optical system also meets the following conditions: 1.5≤ ≤1.75； 。 7. The compact telephoto optical system as described in claim 1, characterized in that: The second lens (L2) and the third lens (L3) are cemented lenses, the fifth lens (L5) and the sixth lens (L6) are cemented lenses, the seventh lens (L7) and the eighth lens (L8) are cemented lenses, and the ninth lens (L9) and the tenth lens (L10) are cemented lenses.

8. The compact telephoto optical system as described in claim 1, characterized in that: The small telephoto optical system also meets the following conditions: ； ； ； ； in, The effective focal length of the first lens (L1) is... The combined effective focal length of the second lens (L2) and the third lens (L3) is... The effective focal length of the fourth lens (L4) is... The combined effective focal length of the seventh lens (L7) and the eighth lens (L8) is... The combined effective focal length of the ninth lens (L9) and the tenth lens (L10) is in mm.

9. The compact telephoto optical system as described in claim 1, characterized in that: The small telephoto optical system also meets the following conditions: in, The center thickness of the first lens (L1) is... The thickness of the center of the eighth lens (L8) is in mm.

10. The compact telephoto optical system as described in claim 1, characterized in that: The first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), the sixth lens (L6), the seventh lens (L7), the eighth lens (L8), the ninth lens (L9), and the tenth lens (L10) are all glass spherical lenses.

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