High-definition athermalization optical lens

Abstract

The invention discloses a high-definition athermalization optical lens. The optical lens sequentially comprises a front lens group, an aperture diaphragm and a rear lens group from an object side to an image side along an optical axis. The front lens group comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, wherein the first lens, the second lens and the third lens have negative focal power, and the fourth lens and the fifth lens have positive focal power. And the rear lens group comprises a sixth lens with negative focal power, a seventh lens with positive focal power and an eighth lens with positive focal power. Wherein the third lens, the fourth lens, the sixth lens and the seventh lens are at least combined into two bonding lenses. The optical lens is compact in structure, fully meets the requirement of miniaturization development, successfully solves the problem that miniaturization and high definition of an existing optical lens are difficult to consider at the same time, basically has no thermal out-of-focus phenomenon under various temperature conditions, the imaging quality is kept at a high level all the time, and the optical lens is suitable for large-scale popularization and application. The stability of the lens used in a complex environment is remarkably enhanced, and more excellent use experience is brought to a user.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and particularly to a high-definition athermalized optical lens. Background Art

[0002] With the continuous progress of technology and the continuous expansion of application fields, high-definition optical lenses have become increasingly prominent in modern society. However, most current high-definition optical lenses are not only bulky but also costly. At the same time, in the face of complex and changing environmental temperatures, especially in high-temperature and low-temperature environments, the imaging quality of the lenses generally deteriorates significantly, which also limits the application of the lenses to a certain extent. Summary of the Invention

[0003] To solve the above problems, the present invention aims to provide a new optical architecture, specifically a high-definition athermalized optical lens. This architecture uses a smaller number of lenses and a smaller system volume. By reasonably distributing the optical power and relative positions of each lens, the production cost and assembly difficulty are reduced, and at the same time, the influence of thermal effects on the imaging quality is effectively reduced, thereby improving the stability and reliability of the optical system operating in complex environments.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A high-definition athermalized optical lens, which sequentially includes a front lens group with positive optical power, an aperture stop, and a rear lens group with positive optical power from the object plane to the image plane;

[0006] The front lens group includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens; wherein:

[0007] The first lens has negative optical power, its object surface is convex, and its image surface is concave;

[0008] The second lens has negative optical power, its object surface is concave, and its image surface can be concave or convex;

[0009] The third lens has negative optical power, and both its object surface and image surface are concave;

[0010] The fourth lens has positive optical power, and both its object surface and image surface are convex;

[0011] The fifth lens has positive optical power, its object surface is convex, and its image surface can be concave or convex;

[0012] The rear lens group includes a sixth lens, a seventh lens, and an eighth lens; wherein:

[0013] The sixth lens has negative optical power, and both its object surface and image surface are concave;

[0014] The seventh lens has a positive focal power, and both its object surface and image surface are convex surfaces;

[0015] The eighth lens has a positive focal power, and both its object surface and image surface are convex surfaces;

[0016] Wherein, the effective focal length EFFL of the optical lens and the overall optical length TTL satisfy EFFL / TTL < 0.3;

[0017] The maximum field of view DFOV of the optical lens and the effective focal length EFFL satisfy EFFL / tan(DFOV) > 7.5;

[0018] The third lens, the fourth lens, the sixth lens and the seventh lens are at least combined into a group of doublet lenses; and there is at least one aspherical lens in the optical system.

[0019] Furthermore, the maximum diameter D of the lens in the optical lens max and the overall optical length TTL of the lens satisfy D max / TTL < 0.4.

[0020] At least one of the first lens and the eighth lens is an aspherical lens.

[0021] When the first lens is an aspherical lens, it is a negative meniscus glass lens, which reduces the spherical aberration of the optical system and improves the thermal stability of the system.

[0022] The Abbe numbers of the third lens, the fourth lens, the sixth lens and the seventh lens are VD3, VD4, VD6, VD7 respectively, and VD3, VD4, VD6, VD7 satisfy: 29 < VD3, VD4 < 45, VD6 < 30, VD7 > 60.

[0023] All the lenses in the optical lens are glass lenses.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The first lens in the front lens group of the optical lens is a meniscus negative lens, which can effectively reduce the spherical aberration of the system. At the same time, the third lens and the fourth lens with high refractive index are combined into a doublet lens. While correcting chromatic aberration, it further converges the off-axis field light, reducing the influence of off-axis aberration on image quality. The fifth lens is a meniscus positive lens, which undertakes the main optical power of the front lens group and weakens the field curvature of the overall optical system. At the same time, the sixth lens and the seventh lens are combined into a doublet lens. While correcting the remaining chromatic aberration of the front lens group, it reduces the air gap between the lenses and compresses the volume of the optical system. Finally, in the present invention, by designing the eighth lens as a glass aspherical lens or designing the first lens as a glass aspherical lens, the remaining spherical aberration and other off-axis aberrations of the system are effectively improved, the imaging quality is further enhanced, and the thermal stability of the system is enhanced.

[0026] Through reasonable optical power distribution, this optical architecture effectively avoids the incidence of large-angle light and reduces the loss of light refraction and scattering. At the same time, this architecture significantly reduces the tolerance sensitivity, which means that even if there are certain deviations during the assembly process, the overall performance and stability of the system can be maintained. Brief Description of the Drawings

[0027] Figure 1 Shows the structural schematic diagram of the optical lens provided in Embodiment 1 of the present invention;

[0028] Figure 2 Shows the ray tracing diagram provided in Embodiment 1 of the present invention;

[0029] Figure 3 Shows the MTF (Modulation Transfer Function) curve graph under normal temperature (20°C) conditions provided in Embodiment 1 of the present invention;

[0030] Figure 4 Shows the MTF (Modulation Transfer Function) curve graph under low temperature (-20°C) conditions provided in Embodiment 1 of the present invention;

[0031] Figure 5 Shows the MTF (Modulation Transfer Function) curve graph under high temperature (85°C) conditions provided in Embodiment 1 of the present invention;

[0032] Figure 6 Shows the spot diagram under normal temperature (20°C) conditions provided in Embodiment 1 of the present invention.

[0033] Figure 7 Shows the distortion schematic diagram A of Embodiment 1 of the present invention;

[0034] Figure 8 Shows the distortion schematic diagram B of Embodiment 1 of the present invention;

[0035] Figure 9Shows the axial chromatic aberration schematic diagram of Embodiment 1 of the present invention;

[0036] Figure 10 Shows the lateral chromatic aberration schematic diagram of Embodiment 1 of the present invention.

[0037] Among them, the above-mentioned drawings include the following markings:

[0038] The first lens group G1; the first lens L1; the second lens L2; the third lens L3; the fourth lens L4; the fifth lens L5; the aperture stop STOP; the second lens group G2; the sixth lens L6; the seventh lens L7; the eighth lens L8; the prism 01; the protective glass 02; the image chip 03. Detailed implementation manners

[0039] Next, in combination with the drawings and specific embodiments, the technical solutions of the present invention will be described in detail.

[0040] As Figure 1 shown, a high-definition athermalized optical lens sequentially includes, from the object surface to the image surface, a front lens group G1 with positive optical power, an aperture stop STOP, and a rear lens group G2 with positive optical power, an equivalent right-angle prism 01, a protective glass 02, and an image chip 03.

[0041] The front lens group G1 includes a first lens L1, a second lens L2, and a third lens L3 with negative optical power, and a fourth lens L4 and a fifth lens L5 with positive optical power.

[0042] The rear lens group G2 includes a sixth lens L6 with negative optical power, a seventh lens L7 with positive optical power, and an eighth lens L8. Among them, at least the third lens, the fourth lens, the sixth lens, and the seventh lens are combined into a group of doublet lenses, and there is at least one aspherical lens in the optical system. Preferably, at least one of the first lens and the eighth lens is an aspherical lens. When the first lens is an aspherical lens, it is a negative meniscus glass lens, which improves the thermal stability of the system while reducing the spherical aberration of the optical system. The Abbe numbers of the third lens, the fourth lens, the sixth lens, and the seventh lens are VD3, VD4, VD6, and VD7 respectively, and VD3, VD4, VD6, and VD7 satisfy: 29 < VD3, VD4 < 45, VD6 < 30, VD7 > 60.

[0043] The lenses in the optical lens are all glass lenses, and:

[0044] The first lens has negative optical power, its object surface is convex, and its image surface is concave;

[0045] The second lens has negative optical power, its object surface is concave, and its image surface can be concave or convex;

[0046] The third lens has a negative optical power, and both its object surface and image surface are concave surfaces;

[0047] The fourth lens has a positive optical power, and both its object surface and image surface are convex surfaces;

[0048] The fifth lens has a positive optical power, its object surface is convex, and its image surface can be concave or convex;

[0049] The sixth lens has a negative optical power, and both its object surface and image surface are concave surfaces;

[0050] The seventh lens has a positive optical power, and both its object surface and image surface are convex surfaces;

[0051] The eighth lens has a positive optical power, and both its object surface and image surface are convex surfaces.

[0052] The aperture stop is located between the front group of lenses and the rear group of lenses, which can significantly reduce optical aberrations.

[0053] For the optical lens, the object surface and image surface of the first lens L1 are S1 and S2 respectively; the object surface and image surface of the second lens L2 are S3 and S4 respectively; the object surface and image surface of the third lens L3 are S5 and S6 respectively; the object surface and image surface of the fourth lens L4 are S7 and S8 respectively; the object surface and image surface of the fifth lens L5 are S9 and S10 respectively; the aperture stop STOP is S11; the object surface and image surface of the sixth lens L6 are S12 and S13 respectively; the object surface and image surface of the seventh lens L7 are S14 and S15 respectively; the object surface and image surface of the eighth lens L8 are S16 and S17 respectively; the object surface and image surface of the prism are S18 and S19 respectively; the object surface and image surface of the protective glass are S20 and S21 respectively; the image surface is S22.

[0054] In this Embodiment 1, the first lens is a meniscus negative lens, the second lens is a biconcave negative lens, the fifth lens is a meniscus positive lens, and the eighth lens is a glass aspherical lens.

[0055] In this Embodiment 3, the first lens is a negative meniscus aspherical lens. It not only shortens the total length of the system but also reduces the spherical aberration of the system.

[0056] For the optical lens, the maximum field of view angle DFOV and the effective focal length EFFL satisfy EFFL / tan(DFOV)>7.5.

[0057] For the lens, the total optical length TTL and the effective focal length EFFL satisfy EFFL / TTL<0.3. The maximum diameter D of the lens in the optical lens max and the total optical length TTL of the lens satisfy D max / TTL<0.4. Within the above range, it is beneficial to realize the miniaturization of the optical system.

[0058] In summary, the optical architecture of the present invention is reasonable, and the distortion is controlled within 1.10%. By reasonably distributing the optical power of each lens, while effectively improving the optical performance of the lens, good processability is ensured. In addition, this structure has a low sensitivity to tolerances, which means that during the manufacturing and assembly processes, even if there are certain parameter deviations, good optical performance stability can be maintained.

[0059] This design not only ensures high-quality optical performance but also reduces production costs and assembly difficulties. Therefore, the present invention has a series of advantages such as high resolution, small structural volume, and strong practicability.

[0060] The specific embodiments are shown in the following table:

[0061] Table 1 below shows the basic structural parameter table of the optical lens of Embodiment 1:

[0062]

[0063] Table 1

[0064] In Table 1, the eighth lens L8 is an even aspherical lens, and the remaining lenses are all spherical lenses. Among them, the even aspherical formula is:

[0065]

[0066] Among them, in the formula, the parameter c is the curvature corresponding to the radius, r is the radial height of the lens, k is the conic constant, and a2 to a6 are the aspherical coefficients corresponding to the second to twelfth orders respectively.

[0067] The preferred values of the even aspherical parameters of the object surface S16 and the image surface S17 of the eighth lens L8 are shown in Table 2:

[0068]

[0069] Table 2

[0070] Table 3 shows the curvature radius R, thickness / distance, refractive index Nd, and dispersion coefficient Vd of each lens of the optical lens of Embodiment 2.

[0071]

[0072] Table 3

[0073] The preferred values of the even aspherical parameters of the object surface S16 and the image surface S17 of the eighth lens L8 are shown in Table 4:

[0074]

[0075] Table 4

[0076] In Embodiment 3, the present invention uses the first lens L1 instead of the eighth lens L8 as the aspherical lens. This glass aspherical lens is a meniscus negative lens, which reduces the NA value of the optical system, further reduces the overall spherical aberration of the optical system, and improves the image quality.

[0077] Table 5 shows the radius of curvature R, thickness / distance, refractive index Nd, and dispersion coefficient Vd of each lens of the optical lens in Embodiment 3. The specific parameters are as follows:

[0078]

[0079] Table 5

[0080] The preferred values of the even aspherical parameters of the object surface S1 and the image surface S2 of the first lens L1 are as

[0081] shown in Table 6:

[0082]

[0083] Table 6

[0084] Figure 3 , Figure 4 and Figure 5 are the schematic diagrams of the imaging MTF of Embodiment 1 at different temperatures. It can be Figure 3 seen that the MTF of the entire field of view of this optical lens is higher than 0.49, and within the range of -20°C to 85°C, the meridional and sagittal curves coincide well, the astigmatism is small, and the image quality stability is high.

[0085] Figure 6 is the spot diagram of Embodiment 1 provided under normal temperature (20°C) conditions. It can be Figure 3 seen that this optical lens has a good correction effect on aberrations such as chromatic aberration, astigmatism, and field curvature.

[0086] Figure 7 and Figure 8 are the distortion schematic diagrams of Embodiment 1 of the present invention. The maximum distortion of this optical lens is 1.0235%.

[0087] Figure 9 is the axial chromatic aberration schematic diagram of Embodiment 1 of the present invention.

[0088] Figure 10 is the lateral chromatic aberration schematic diagram of Embodiment 1 of the present invention. Since this optical structure uses two groups of doublet lenses, the chromatic aberration of this structure is small. During actual use, there will be no obvious color separation at the edge of the projection screen.

[0089] In summary, with fewer lenses, this optical structure effectively eliminates various optical aberrations by reasonably distributing the optical power of the optical lenses. While ensuring the optical image quality, it controls the volume of the optical system and meets the requirements of the miniaturization development of vehicle-mounted devices.

[0090] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

[0091] It should be noted that the terms "first", "second", etc. in the specification, claims and drawings of this application are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of this application described here can be implemented in an order other than those illustrated or described here.

Claims

1. A high-definition athermal optical lens, characterized in that: The lens system includes, from the object plane to the image plane, a front lens group with positive power, an aperture stop, and a rear lens group with positive power; the front lens group includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens; wherein: The first lens has negative optical power, its object surface is convex and its image surface is concave; The second lens has negative optical power, its object surface is concave, and its image surface can be concave or convex; The third lens has negative optical power, and its object surface and image surface are both concave; The fourth lens has positive refractive power, and its object surface and image surface are both convex; The fifth lens has positive refractive power, its object surface is convex, and its image surface can be concave or convex; The rear lens group includes a sixth lens, a seventh lens and an eighth lens; wherein: The sixth lens has negative optical power, and its object surface and image surface are both concave; The seventh lens has positive refractive power, and its object surface and image surface are both convex; The eighth lens has positive refractive power, and its object surface and image surface are both convex; Wherein, the effective focal length EFFL of the optical lens and the total optical length TTL satisfy EFFL / TTL<0.3; The maximum field of view DFOV and the effective focal length EFFL of the optical lens satisfy the condition that EFFL / tan(DFOV)>7.5; The third lens, the fourth lens, the sixth lens and the seventh lens are combined into at least one group of doublet lenses; and there is at least one aspherical lens in the optical system.

2. The high-definition athermal optical lens according to claim 1, characterized in that: The maximum diameter D of the lens in the optical lens max The total optical length of the lens meets TTL, D max / TTL<0.

4.

3. The high-definition athermal optical lens according to claim 1, characterized in that: At least one of the first lens and the eighth lens is an aspherical lens.

4. The high-definition athermal optical lens according to claim 1, characterized in that: When the first lens is used as an aspherical lens, it is a negative meniscus glass lens, which reduces the spherical aberration of the optical system and improves the thermal stability of the system.

5. The high-definition athermal optical lens according to claim 1, characterized in that: The Abbe numbers of the third lens, the fourth lens, the sixth lens and the seventh lens are VD3, VD4, VD6 and VD7 respectively, and VD3, VD4, VD6 and VD7 satisfy: 29<VD3, VD4<45, VD6<30, VD7>60.

6. The high-definition athermal optical lens according to claim 5, characterized in that: The lenses in the optical lens are all glass lenses.

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