Optical system

Abstract

The present invention provides an optical system comprising: a lens group in which a first lens having a negative refractive power, a second lens having a positive refractive power, and a third lens having a positive refractive power are sequentially provided; the spacing elements are located between the first lens and the second lens and at least partially abut against the light source side face of the first lens, and the spacing elements are located between the second lens and the third lens and at least partially abut against the light source side face of the second lens; a lens barrel; the air space between the first lens and the second lens on the optical axis is maximum; the inner diameter d1m of the light source side face of the first spacing element and the air spacing T12 of the first lens and the second lens on the optical axis meet the condition that d1m / T12 is larger than or equal to 0.96 and smaller than or equal to 3.15. The air interval T12 of the first lens and the second lens on the optical axis and the maximum thickness CP1 of the first interval element meet the condition that T12 / CP1 is larger than or equal to 1.17 and smaller than or equal to 6.69. The problem that stray light at one end, close to the imaging side, of a three-piece optical system in the prior art is serious is solved.

Description

Technical Field

[0001] This invention relates to the field of optical imaging equipment technology, and more specifically, to an optical system. Background Technology

[0002] With the rapid development of the VR / AR / MR industry, various types of head-mounted imaging devices have emerged on the market. Among these, the optical system, as a crucial component of such electronic products, is receiving increasing attention from consumers. In particular, the three-element wide-angle optical system, while ensuring effective light transmission, suffers from significant light refraction over a large field of view. Furthermore, the large air gap between the first and second lenses leads to a higher risk of stray light reflection from the lens mechanism and the inner diameter surface of the spacer element near the imaging end, thus affecting image quality. Therefore, controlling the shape and size of the lens and spacer element near the imaging end of the three-element optical system to reduce stray light impact is a critical issue. Summary of the Invention

[0003] The main objective of this invention is to provide an optical system that solves the problem of severe stray light at the end of the three-element optical system near the imaging side in the prior art.

[0004] To achieve the above objectives, according to one aspect of the present invention, an optical system is provided, comprising: a lens group having three lenses having optical power, wherein a first lens having negative optical power, a second lens having positive optical power, and a third lens having positive optical power are sequentially arranged from the imaging side of the optical system to the light source side of the optical system; and a plurality of spacers, wherein the first spacer is located between the first lens and the second lens and at least partially abuts against the light source side of the first lens, and the spacers are located between the second lens and the third lens and abut against the light source side of the second lens. The source side is at least partially supported by a second spacer element; the lens barrel, lens group and multiple spacer elements are all housed in the lens barrel; among them, the first lens and the second lens have the largest air gap on the optical axis of the optical system; the inner diameter d1m of the source side of the first spacer element and the air gap T12 of the first lens and the second lens on the optical axis satisfy: 0.96≤d1m / T12≤3.15; the air gap T12 of the first lens and the second lens on the optical axis and the maximum thickness CP1 of the first spacer element satisfy: 1.17≤T12 / CP1≤6.69.

[0005] According to one aspect of the present invention, an optical system is provided, comprising: a lens group having three lenses having optical power, wherein a first lens having negative optical power, a second lens having positive optical power, and a third lens having positive optical power are sequentially arranged from the imaging side to the light source side of the optical system; and a plurality of spacer elements, wherein a first spacer element is located between the first lens and the second lens and at least partially abuts against the light source side of the first lens, and a second spacer element is located between the second lens and the third lens and at least partially abuts against the light source side of the second lens. Spacer elements; a lens barrel, a lens group, and multiple spacer elements are all housed in the lens barrel; among them, the first lens and the second lens have the largest air gap on the optical axis of the optical system; the inner diameter d1m of the light source side of the first spacer element and the air gap T12 of the first lens and the second lens on the optical axis satisfy: 0.96≤d1m / T12≤3.15; the center thickness CT2 of the second lens on the optical axis, the center thickness CT1 of the first lens on the optical axis, and the maximum thickness CP1 of the first spacer element satisfy: 0.56≤CT2 / (CT1+CP1)≤1.43.

[0006] Furthermore, the inner diameter d1s of the imaging side of the first spacer element and the center thickness CT1 of the first lens on the optical axis satisfy the following condition: 2.08≤d1s / CT1≤7.20.

[0007] Furthermore, the effective focal length f1 of the first lens and the inner diameter d1s of the imaging side of the first spacer element satisfy the following condition: -2.57≤d1s / f1≤-1.08.

[0008] Furthermore, the radius of curvature R1 of the imaging side of the first lens and the radius of curvature R2 of the light source side of the first lens satisfy the following: -6.2964≤R1 / R2≤6.6283; the outer diameter D1s of the imaging side of the first spacer element and the radius of curvature R2 of the light source side of the first lens satisfy the following: 3.56≤D1s / R2≤6.67.

[0009] Furthermore, the combined focal length f12 of the first lens and the second lens, and the distance EP12 between the first spacer element and the second spacer element along the optical axis satisfy the following condition: 0.93≤f12 / EP12≤2.59.

[0010] Furthermore, the center thickness CT2 of the second lens on the optical axis and the distance EP12 between the first spacer element and the second spacer element along the optical axis satisfy the following condition: 1.05≤CT2 / EP12≤2.05.

[0011] Furthermore, the effective focal length f2 of the second lens and the inner diameter d2s of the imaging side of the second spacer element satisfy the following condition: 0.54≤f2 / d2s≤1.16.

[0012] Furthermore, the radius of curvature R3 of the imaging side of the second lens and the inner diameter d1m of the imaging side of the second spacer element satisfy the following: -2.09≤d1m / R3≤1.59; the radius of curvature R4 of the light source side of the second lens and the inner diameter d2s of the imaging side of the second spacer element satisfy the following: -2.77≤d2s / R4≤-1.85.

[0013] Furthermore, the center thickness CT2 of the second lens on the optical axis, the center thickness CT1 of the first lens on the optical axis, and the maximum thickness CP1 of the first spacer element satisfy the following condition: 0.56≤CT2 / (CT1+CP1)≤1.43.

[0014] Furthermore, the effective focal length f3 of the third lens and the inner diameter d2m of the light source side of the second spacer element satisfy the following condition: 0.76≤f3 / d2m≤3.47.

[0015] Furthermore, among the multiple spacer elements, the one located between the first spacer element and the first lens and at least partially abutting against the light source side of the first spacer element is the first auxiliary spacer element. The central thickness CT1 of the first lens on the optical axis and the inner diameter d1bs of the imaging side of the first auxiliary spacer element satisfy the following: 0.29≤CT1 / d1bs≤0.83.

[0016] Furthermore, the air gap T23 between the second and third lenses on the optical axis, the maximum thickness CP2 of the second spacer element, and the center thickness CT3 of the third lens on the optical axis satisfy the following condition: 1.44≤CT3 / (T23+CP2)≤6.04.

[0017] Furthermore, the inner diameter d2m of the light source side of the second spacer element, the air gap T23 between the second and third lenses on the optical axis, and the center thickness CT3 of the third lens on the optical axis satisfy the following: 2.18≤d2m / (T23+CT3)≤4.32.

[0018] Furthermore, the light source side of the first lens is concave, the light source side of the second lens is convex, and the light source side of the third lens is convex.

[0019] According to the technical solution of this invention, the optical system includes a lens group, multiple spacer elements, and a lens barrel. The lens group has three lenses with optical power. From the imaging side to the light source side of the optical system, a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power are arranged sequentially. Among the multiple spacer elements, the first spacer element is located between the first lens and the second lens and at least partially abuts against the light source side of the first lens, and the second spacer element is located between the second lens and the third lens and at least partially abuts against the light source side of the second lens. The lens group and the multiple spacer elements are all housed within the lens barrel. The air gap between the first lens and the second lens on the optical axis of the optical system is the largest. The inner diameter d1m of the light source side of the first spacer element and the air gap T12 between the first lens and the second lens on the optical axis satisfy the following: 0.96≤d1m / T12≤3.15. The air gap T12 between the first lens and the second lens on the optical axis and the maximum thickness CP1 of the first spacer element satisfy the following: 1.17≤T12 / CP1≤6.69.

[0020] This application's three-element wide-angle optical system satisfies the aforementioned power ratio and 0.96≤d1m / T12≤3.15. The air gap between the first and second lenses on the optical axis is the largest. The large field-of-view light is significantly deflected by the second lens, leading to a higher risk of edge light rays incident on the inner diameter surface of the first spacer element or even the structural portion of the first lens, thus generating a large amount of stray light. This application, by controlling the air gap between the first and second lenses on the optical axis and the maximum thickness of the first spacer element, can indirectly control the shape of the first and second lenses, thereby controlling the light trajectory, reducing the risk of internal reflection stray light generation on the inner diameter surface of the first spacer element, and preventing light rays from incident on the structural portion of the first lens, further aggravating stray light. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 A schematic diagram showing partial parameters of the optical system of any optional embodiment of the present invention is shown;

[0023] Figure 2 A schematic diagram of the optical system according to Embodiment 1 of the present invention is shown;

[0024] Figure 3 The on-axis chromatic aberration curve of the optical system according to Embodiment 1 of the present invention is shown;

[0025] Figure 4 The astigmatism curve of the optical system of Embodiment 1 of the present invention is shown;

[0026] Figure 5 The magnification chromatic aberration curve of the optical system of Embodiment 1 of the present invention is shown;

[0027] Figure 6 A schematic diagram of the optical system according to Embodiment 2 of the present invention is shown;

[0028] Figure 7 A schematic diagram of the optical system according to Embodiment 3 of the present invention is shown;

[0029] Figure 8 A schematic diagram of the optical system according to Embodiment 4 of the present invention is shown;

[0030] Figure 9 The on-axis chromatic aberration curve of the optical system of Embodiment 4 of the present invention is shown;

[0031] Figure 10 The astigmatism curve of the optical system of Embodiment 4 of the present invention is shown;

[0032] Figure 11 The magnification chromatic aberration curve of the optical system of Embodiment 4 of the present invention is shown;

[0033] Figure 12 A schematic diagram of the optical system according to Embodiment 5 of the present invention is shown;

[0034] Figure 13 A schematic diagram of the optical system according to Embodiment Six of the present invention is shown;

[0035] Figure 14 A schematic diagram of the optical system according to Embodiment 7 of the present invention is shown;

[0036] Figure 15 The on-axis chromatic aberration curve of the optical system of Embodiment 7 of the present invention is shown;

[0037] Figure 16 The astigmatism curve of the optical system of Embodiment 7 of the present invention is shown;

[0038] Figure 17 The magnification chromatic aberration curve of the optical system of Embodiment 7 of the present invention is shown;

[0039] Figure 18 A schematic diagram of the optical system of Embodiment 8 of the present invention is shown;

[0040] Figure 19 A schematic diagram of the optical system according to Embodiment 9 of the present invention is shown;

[0041] Figure 20The diagram shows a stray light spot pattern near the imaging side of an optical system of an alternative embodiment 1 of the present invention under the condition 1.17≤T12 / CP1≤6.69.

[0042] Figure 21 The stray light spot pattern of the optical system of Comparative Example 1 is shown near the imaging side under the condition T12 / CP1≤1.12.

[0043] Figure 22 The image shows stray light spots near the imaging side of the optical system in Comparative Example 2 under the condition T12 / CP1>6.74.

[0044] The above figures include the following reference numerals:

[0045] P0, Lens tube; E1, First lens; S1, Imaging side of the first lens; S2, Light source side of the first lens; P1, First spacer element; P1b, First auxiliary spacer element; E2, Second lens; S3, Imaging side of the second lens; S4, Light source side of the second lens; P2, Second spacer element; P2b, Second auxiliary spacer element; E3, Third lens; S5, Imaging side of the third lens; S6, Light source side of the third lens. Detailed Implementation

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0048] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0049] 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 this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0050] 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 drawn strictly to scale.

[0051] In this paper, the paraxial region refers to the area near the optical axis. If the lens surface is convex and its location is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and its location is not defined, it means that the lens surface is concave at least in the paraxial region. The surface shape in the paraxial region can be determined by the sign of the R value (R refers to the radius of curvature of the paraxial region, usually the R value in the lens data in optical software). For the imaging side surface, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave; for the light source side surface, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex.

[0052] In this paper, effective light refers to light rays that can be accurately focused onto the imaging surface, either directly or after refraction within the optical system. These rays follow optical laws, such as the laws of refraction and reflection, as they pass through the optical system, ultimately forming a clear image on the imaging surface.

[0053] In this article, ineffective light refers to light rays that do not participate in the imaging process. This includes light rays that enter the optical system but are not focused on the imaging surface, or light rays that are scattered, reflected, or absorbed within the optical system. Ineffective light rays can be caused by physical limitations in the optical system design (such as asymmetrical or imperfect lens shapes), or by factors such as unevenness, dust, scratches, or uneven coatings on the surface of optical elements. Ineffective light rays not only fail to improve image quality but may also lead to undesirable effects such as image blurring, reduced contrast, or the production of light spots and glare.

[0054] In this paper, each lens consists of an integrally formed effective diameter portion and a mechanism portion. The mechanism portion is annular and connected to the outer peripheral side of the effective diameter portion. The effective diameter portion is used for light to pass through and participate in imaging; while the mechanism portion is not used for light to pass through and does not participate in imaging, but is used to contact adjacent spacer elements, adjacent lenses, or lens barrels.

[0055] To address the problem of severe stray light at the imaging end of existing three-element optical systems, this invention provides an optical system.

[0056] First Implementation Method

[0057] like Figures 1 to 20As shown, the optical system includes a lens group, multiple spacers, and a lens barrel. The lens group has three lenses with optical power. From the imaging side to the light source side of the optical system, a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power are arranged sequentially. Among the multiple spacers, the first spacer is located between the first and second lenses and at least partially abuts the light source side of the first lens, while the second spacer is located between the second and third lenses and at least partially abuts the light source side of the second lens. The lens group and multiple spacers are all housed within the lens barrel. The air gap between the first and second lenses on the optical axis of the optical system is the largest. The inner diameter d1m of the light source side of the first spacer and the air gap T12 between the first and second lenses on the optical axis satisfy the following: 0.96≤d1m / T12≤3.15. The air gap T12 between the first and second lenses on the optical axis and the maximum thickness CP1 of the first spacer satisfy the following: 1.17≤T12 / CP1≤6.69.

[0058] This application's three-element wide-angle optical system satisfies the aforementioned power ratio and 0.96≤d1m / T12≤3.15. The air gap between the first and second lenses on the optical axis is the largest. The large field-of-view light is significantly deflected by the second lens, leading to a higher risk of edge light rays incident on the inner diameter surface of the first spacer element or even the structural portion of the first lens, thus generating a large amount of stray light. This application, by controlling the air gap between the first and second lenses on the optical axis and the maximum thickness of the first spacer element, can indirectly control the shape of the first and second lenses, thereby controlling the light trajectory, reducing the risk of internal reflection stray light generation on the inner diameter surface of the first spacer element, and preventing light rays from incident on the structural portion of the first lens, further aggravating stray light.

[0059] As shown in Table 1 and Figures 20 to 22 As shown, stray light spot diagrams are presented for the optical systems of Comparative Example 1, Comparative Example 2, and an alternative scheme 1 of this application, under the condition of the same d1m / T12 but different T12 / CP1, near the imaging side. It should be noted that during the simulation, the matrix light source is positioned on the imaging side of the optical system to simulate stray light distribution in reverse, and the image is cropped in the projection direction. Therefore, in the stray light spot diagram of this application, the brighter and more concentrated arc-shaped area on the left is the location of the matrix light source, and the spot to the right of the matrix light source shows the stray light distribution.

[0060] Table 1

[0061]

[0062] As shown in Table 1 and Figure 21As shown, the optical system of Comparative Example 1 is presented, satisfying the conditions d1m / T12=0.02 and T12 / CP1=12. The risk of multiple reflections of stray light from the inner diameter surface of the first spacer element is high, and the stray light is more pronounced near the imaging side of the optical system, exhibiting a relatively concentrated thin stripe distribution on the right side of the matrix light source's spot. For example... Figure 22 As shown, the optical system of Comparative Example 2 satisfies the conditions d1m / T12 = 8.00 and T12 / CP1 = 0.02. However, the distance between the first and second lenses is too large, increasing the risk of edge incidence on the inner diameter surface of the first spacer element and the mechanism of the first lens. This results in severe stray light near the imaging side of the optical system, exhibiting a relatively dispersed, patchy distribution on the right side of the matrix light source's spot. In contrast, Scheme 1 of this application... Figure 20 As shown, under the conditions of d1m / T12=1.89 and T12 / CP1=3.02, that is, 0.96≤d1m / T12≤3.15 and 1.17≤T12 / CP1≤6.69, the stray light spot near the imaging side of the optical system is effectively controlled.

[0063] In this embodiment, the inner diameter d1s of the imaging side of the first spacer element and the center thickness CT1 of the first lens on the optical axis satisfy the following condition: 2.08 ≤ d1s / CT1 ≤ 7.20. By limiting d1s / CT1 within a reasonable range, the inner diameter of the imaging side of the first spacer element can be controlled, thereby controlling the size of the mating fit between the first spacer element and the light source side of the first lens, enhancing assembly stability. At the same time, the center thickness of the first lens on the optical axis can be controlled, thereby ensuring the manufacturability of the first lens, and thus simultaneously reducing the risk of assembly instability and component processing defects.

[0064] In this embodiment, the effective focal length f1 of the first lens and the inner diameter d1s of the imaging side of the first spacer element satisfy the following condition: -2.57 ≤ d1s / f1 ≤ -1.08. By limiting d1s / f1 within a reasonable range, the trajectory of light within the first lens can be constrained, ensuring that the principal ray transmitted from the second lens is effectively converged, ultimately controlling the magnitude of the principal ray's exit angle. Simultaneously, the inner diameter of the imaging side of the first spacer element can be constrained, ensuring that light is not blocked and that the overall optical performance remains within the design range.

[0065] In this embodiment, the radius of curvature R1 of the imaging side of the first lens and the radius of curvature R2 of the light source side of the first lens satisfy the following condition: -6.2964 ≤ R1 / R2 ≤ 6.6283; the outer diameter D1s of the imaging side of the first spacer element and the radius of curvature R2 of the light source side of the first lens satisfy the following condition: 3.56 ≤ D1s / R2 ≤ 6.67. By limiting R1 / R2 and D1s / R2 to a reasonable range, the surface shape trend of the light source side and imaging side of the first lens can be controlled, which is beneficial to the molding and processing of the first lens. At the same time, the effective focal length of the first lens can be controlled to ensure optical performance. In addition, controlling the outer diameter of the imaging side of the first spacer element can control the misalignment between the first spacer element and the first lens, reducing the risk of deformation of the first lens caused by excessive misalignment during assembly.

[0066] In this embodiment, the combined focal length f12 of the first and second lenses and the distance EP12 between the first and second spacers along the optical axis satisfy the following condition: 0.93 ≤ f12 / EP12 ≤ 2.59. By limiting f12 / EP12 within a reasonable range, the trend and direction of light between the first and second lenses can be controlled, reducing the sensitivity of the first and second lenses. Simultaneously, the position and surface shape of the third lens can be controlled and adjusted, improving the symmetry of the overall optical system structure. Combined with the control of the edge thickness of the second lens, this facilitates the injection molding process of the optical system.

[0067] In this embodiment, the center thickness CT2 of the second lens along the optical axis and the distance EP12 between the first spacer element and the second spacer element along the optical axis satisfy the following condition: 1.05 ≤ CT2 / EP12 ≤ 2.05. By limiting CT2 / EP12 within a reasonable range, the center thickness and edge thickness of the second lens can be controlled, improving the symmetry of the overall structure of the second lens. This is beneficial for lens mold processing and injection molding, and reduces the risk of stress concentration and structural asymmetry during assembly.

[0068] In this embodiment, the effective focal length f2 of the second lens and the inner diameter d2s of the imaging side of the second spacer element satisfy the following condition: 0.54 ≤ f2 / d2s ≤ 1.16. By limiting f2 / d2s within a reasonable range, the direction and trajectory of light within the second lens can be controlled, ensuring effective transmission of light to the first lens. Simultaneously, the inner diameter of the imaging side of the second spacer element is constrained to prevent light from being blocked during transmission, thus maintaining the overall performance of the optical system.

[0069] In this embodiment, the radius of curvature R3 of the imaging side of the second lens and the inner diameter d1m of the imaging side of the second spacer element satisfy the following: -2.09 ≤ d1m / R3 ≤ 1.59; the radius of curvature R4 of the light source side of the second lens and the inner diameter d2s of the imaging side of the second spacer element satisfy the following: -2.77 ≤ d2s / R4 ≤ -1.85. By limiting d1m / R3 and d2s / R4 within a reasonable range, the shape of the effective diameter portion of the second lens can be controlled, which is beneficial for its processing and shaping. At the same time, by controlling the inner diameter dimensions of the first and second spacers, stray light at the edge of the effective diameter portion of the second lens is effectively blocked, improving image quality and imaging performance.

[0070] In this embodiment, the center thickness CT2 of the second lens on the optical axis, the center thickness CT1 of the first lens on the optical axis, and the maximum thickness CP1 of the first spacer element satisfy the following condition: 0.56 ≤ CT2 / (CT1+CP1) ≤ 1.43. By limiting CT2 / (CT1+CP1) within a reasonable range, the sagittal dimensions of the light source side of the first lens and the imaging side of the second lens can be indirectly controlled. Simultaneously, the center thicknesses of the first and second lenses can be controlled, optimizing the structural design of the effective diameter portions and mechanism portions of the first and second lenses. This facilitates processing and forming, reduces irregular deformation, and avoids a decline in optical performance.

[0071] In this embodiment, the effective focal length f3 of the third lens and the inner diameter d2m of the light source side of the second spacer element satisfy the following condition: 0.76 ≤ f3 / d2m ≤ 3.47. By limiting f3 / d2m within a reasonable range, the direction and trajectory of the effective light transmitted to the third lens can be controlled, ensuring effective light transmission within the third lens, thereby controlling the exit angle of the principal ray. Simultaneously, the inner diameter of the light source side of the second spacer element is constrained to ensure that the light is not blocked, maintaining the overall performance of the optical system within the design requirements.

[0072] In this embodiment, among the multiple spacer elements, the first auxiliary spacer element is located between the first spacer element and the first lens and at least partially abuts against the light source side of the first spacer element. The central thickness CT1 of the first lens on the optical axis and the inner diameter d1bs of the imaging side of the first auxiliary spacer element satisfy the following: 0.29 ≤ CT1 / d1bs ≤ 0.83. By limiting CT1 / d1bs within a reasonable range, the abutment fit dimensions between the first lens and the first auxiliary spacer element can be precisely controlled, reducing the abutment misalignment. At the same time, the central thickness of the first lens can be controlled to ensure uniform stress on the first lens during assembly, reducing surface shape changes of the first lens, thereby reducing the impact on field curvature and improving the stability of the overall structure and the consistency of optical performance.

[0073] In this embodiment, the air gap T23 between the second and third lenses on the optical axis, the maximum thickness CP2 of the second spacer element, and the center thickness CT3 of the third lens on the optical axis satisfy the following condition: 1.44 ≤ CT3 / (T23+CP2) ≤ 6.04. By limiting CT3 / (T23+CP2) within a reasonable range, the sagittal dimensions of the light source side of the second lens and the imaging side of the third lens can be effectively controlled. Maintaining the sagittal within a reasonable and controllable range is beneficial for lens molding and filling, reduces the risk of weld lines, and improves the optical matching between lenses and the overall performance of the optical system.

[0074] In this embodiment, the inner diameter d2m of the light source side of the second spacer element, the air gap T23 between the second and third lenses on the optical axis, and the center thickness CT3 of the third lens on the optical axis satisfy the following condition: 2.18 ≤ d2m / (T23+CT3) ≤ 4.32. By limiting d2m / (T23+CT3) within a reasonable range, the air gap between the second and third lenses can be controlled, reducing the impact on field curvature changes. Simultaneously, controlling the inner diameter of the light source side of the second spacer element ensures that edge rays of the optical system are not blocked, maintaining principal optical parameters such as RI and FNO, thereby optimizing the overall design of the optical system and improving the stability of imaging quality and optical performance.

[0075] Second Implementation Method

[0076] like Figures 1 to 20 As shown, the optical system includes a lens group, multiple spacers, and a lens barrel. The lens group has three lenses with optical power. From the imaging side to the light source side of the optical system, a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power are arranged sequentially. Among the multiple spacers, the first spacer is located between the first lens and the second lens and at least partially abuts the light source side of the first lens, and the second spacer is located between the second lens and the third lens and at least partially abuts the light source side of the second lens. The lens group and multiple spacer elements are housed in the lens barrel; among them, the first lens and the second lens have the largest air gap on the optical axis of the optical system; the inner diameter d1m of the light source side of the first spacer element and the air gap T12 of the first lens and the second lens on the optical axis satisfy: 0.96≤d1m / T12≤3.15; the center thickness CT2 of the second lens on the optical axis, the center thickness CT1 of the first lens on the optical axis and the maximum thickness CP1 of the first spacer element satisfy: 0.56≤CT2 / (CT1+CP1)≤1.43.

[0077] This application's three-element wide-angle optical system satisfies the aforementioned power matching and 0.96≤d1m / T12≤3.15. The air gap between the first and second lenses on the optical axis is the largest, resulting in significant deflection of large field-of-view light by the second lens. This increases the risk of edge light rays incident on the inner diameter surface of the first spacer element or even the structural portion of the first lens, generating a large amount of stray light. This application addresses this by controlling the center thickness of the first and second lenses and the maximum thickness of the first spacer element. This allows for indirect control of the sag dimensions of the light source side of the first lens and the imaging side of the second lens. Simultaneously, controlling the center thickness of the first and second lenses optimizes the structural design of their effective diameter portions and structural portions, thereby controlling the light trajectory and reducing the risk of internal reflection stray light on the inner diameter surface of the first spacer element. It also prevents light rays from incident on the structural portion of the first lens, further aggravating stray light. Furthermore, it facilitates lens fabrication, reduces irregular deformation, and avoids a decline in optical performance.

[0078] It should be noted that this embodiment may also include other conditional expressions from the above embodiments, which will not be elaborated here.

[0079] Optionally, the optical system may also include protective glass for protecting the photosensitive element located on the imaging surface.

[0080] The optical system in this application may employ multiple lenses, such as the three lenses described above. In this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. An aspherical lens is characterized by a continuously changing curvature from its center to its periphery. Unlike a spherical lens, which has a constant curvature from its center to its periphery, an aspherical lens has superior curvature radius characteristics, offering advantages in improving distortion and astigmatism. By using aspherical lenses, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality.

[0081] Figure 1 A schematic diagram showing the dimensions of an optical system according to this application is provided. Figure 1 The parameters D1s, d2m, EP12, etc., are indicated to provide a clear and intuitive understanding of their meaning. To facilitate the description of the optical system and the surface shape of specific lenses, these parameters will not be shown in the accompanying drawings when describing specific embodiments.

[0082] It should be noted that in an optical system, the surface closest to the imaging side of the lens barrel is the imaging side end face, and the surface closest to the light source side of the lens barrel is the light source side end face.

[0083] The following description, with reference to the accompanying drawings, further illustrates examples of specific surface shapes and parameters of the optical system applicable to the above embodiments.

[0084] It should be noted that any one of the following embodiments, from Embodiment 1 to Embodiment 9, is applicable to all implementation methods of this application.

[0085] Example 1

[0086] like Figure 2 The optical system of Embodiment 1 of this application is described as shown. Figure 2 A schematic diagram of the optical system of Embodiment 1 is shown.

[0087] like Figure 2 As shown, the optical system, from the imaging side to the light source side, sequentially includes the following components housed within the lens barrel: a first lens E1, a first spacer element P1, a first auxiliary spacer element P1b, a second lens E2, a second spacer element P2, a second auxiliary spacer element P2b, and a third lens E3. The second auxiliary spacer element P2b is located between the second spacer element and the third lens, and at least partially abuts against the light source side of the second spacer element.

[0088] In this embodiment, the first lens E1 has negative optical power, its imaging side S1 is convex, and its light source side S2 is concave. The second lens E2 has positive optical power, its imaging side S3 is concave, and its light source side S4 is convex. The third lens E3 has positive optical power, its imaging side S5 is convex, and its light source side S6 is convex.

[0089] Table 2 shows the basic structural parameters of the optical system in Embodiment 1, where the units for radius of curvature, thickness / distance, and focal length are millimeters (mm). STO (not shown in the figure) is the aperture stop, which is located between the first lens and the second lens.

[0090] Table 2

[0091]

[0092]

[0093] In Embodiment 1, all lenses are aspherical lenses, and the shape of the aspherical surface can be defined using, but is not limited to, the following aspherical formula:

[0094]

[0095] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R, that is, the paraxial curvature c is the reciprocal of the radius of curvature R in Table 2 above; k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 3 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20 that can be used for each aspherical mirror S1-S6 in Example 1.

[0096] Table 3

[0097] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 1.9251E-02 -1.2969E+00 7.6461E+00 -2.4791E+01 5.0140E+01 -6.4116E+01 5.0139E+01 -2.1822E+01 4.0425E+00 S2 4.0535E-01 2.7108E+01 -9.1797E+02 1.5576E+04 -1.5171E+05 8.9351E+05 -3.1366E+06 6.0335E+06 -4.8939E+06 S3 -1.6634E+00 -6.2541E+00 5.9524E+01 -7.4841E+02 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 -2.3628E-01 -4.7328E+00 3.4258E+01 -1.5790E+02 3.9322E+02 -4.3290E+02 0.0000E+00 0.0000E+00 0.0000E+00 S5 3.4305E-01 -4.4192E+00 3.5532E+01 -1.8413E+02 6.5056E+02 -1.5551E+03 2.4181E+03 -2.2143E+03 9.0175E+02 S6 -2.8500E-01 1.8210E-01 3.3411E+00 -2.4308E+01 1.1781E+02 -3.9231E+02 8.3444E+02 -9.9283E+02 4.9167E+02

[0098] Figure 3 The on-axis chromatic aberration curve of the optical system of Embodiment 1 is shown, which represents the deflection of the focal point of light of different wavelengths after passing through the optical system. Figure 4 The astigmatism curves of the optical system of Embodiment 1 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 5 The magnification chromatic aberration curve of the optical system of Embodiment 1 is shown, which represents the degree to which the focal points of light of different wavelengths do not completely coincide.

[0099] according to Figures 3 to 5 As can be seen, the optical system given in Example 1 can achieve good imaging quality.

[0100] Example 2

[0101] like Figure 6 The image shows an optical system according to Embodiment 2 of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment 1, but the structural parameters are different. Please refer to the relevant description in Embodiment 1, which will not be repeated here.

[0102] Example 3

[0103] like Figure 7 The image shows an optical system according to Embodiment 3 of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment 1, but the structural parameters are different. Please refer to the relevant description in Embodiment 1, which will not be repeated here.

[0104] Example 4

[0105] like Figure 8 As shown, an optical system according to Embodiment 4 of this application is described. Figure 8 A schematic diagram of the optical system of Embodiment 4 is shown.

[0106] like Figure 8As shown, the optical system includes, in sequence from the imaging side to the light source side, the following components housed within the lens barrel: a first lens E1, a first spacer element P1, a first auxiliary spacer element P1b, a second lens E2, a second spacer element P2, and a third lens E3.

[0107] In this embodiment, the first lens E1 has negative optical power, and its imaging side S1 and light source side S2 are both concave. The second lens E2 has positive optical power, and its imaging side S3 and light source side S4 are both convex. The third lens E3 has positive optical power, and its imaging side S5 and light source side S6 are both convex.

[0108] Table 4 shows the basic structural parameters of the optical system in Embodiment 4, where the units for radius of curvature, thickness / distance, and focal length are millimeters (mm). STO (not shown in the figure) is the aperture stop, which is located between the first lens and the second lens.

[0109] Table 4

[0110] Face number Surface type radius of curvature Thickness / Distance Refractive index Abbe number Conic coefficient Imaging spherical endless 600.0000 S1 aspherical -3.4435 0.3929 1.63 20.37 0.0000 S2 aspherical 0.5469 0.7566 -0.2081 STO spherical endless 0.3798 S3 aspherical 1.0638 0.7600 1.62 23.52 0.0000 S4 aspherical -0.7023 0.0309 -4.4036 S5 aspherical -2.1913 0.3196 1.62 23.52 0.0000 S6 aspherical -1.3868 0.8177 1.5547 light source spherical endless 0.0000

[0111] In Example 4, all lenses are aspherical lenses, and the shape of the aspherical surface can be defined using, but is not limited to, formula (1) in Example 1. Table 5 below gives the higher-order coefficients that can be used for each aspherical mirror S1-S6 in Example 4.

[0112] Table 5

[0113] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 6.6490E-01 -1.8596E+00 4.3269E+00 -6.9367E+00 6.4748E+00 -1.6870E+00 -3.1938E+00 3.5303E+00 -1.1501E+00 S2 7.1509E-01 3.6844E+01 -1.1521E+03 2.1385E+04 -2.5245E+05 1.9248E+06 -9.0883E+06 2.4009E+07 -2.7039E+07 S3 -2.8769E-01 3.1944E-01 1.1566E-01 -5.2651E+00 1.3508E+01 -1.1289E+01 0.0000E+00 0.0000E+00 0.0000E+00 S4 -2.6819E-01 -1.4328E+00 1.5791E+01 -5.2039E+01 7.4888E+01 -4.0613E+01 0.0000E+00 0.0000E+00 0.0000E+00 S5 -1.8453E-01 -3.3532E+00 1.0169E+01 4.1483E+01 -3.6016E+02 1.1472E+03 -1.9876E+03 1.8740E+03 -7.6119E+02 S6 -7.5763E-01 2.6270E+00 -1.0889E+01 4.5125E+01 -1.0486E+02 1.3161E+02 -6.7365E+01 0.0000E+00 0.0000E+00

[0114] Figure 9 The on-axis chromatic aberration curve of the optical system of Embodiment 4 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the optical system. Figure 10 The astigmatism curves of the optical system of Embodiment 4 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 11 The magnification chromatic aberration curve of the optical system of Embodiment 4 is shown, which represents the degree to which the focal points of light of different wavelengths do not completely coincide.

[0115] according to Figures 9 to 11 As can be seen, the optical system given in Example 4 can achieve good imaging quality.

[0116] Example 5

[0117] like Figure 12 The image shows an optical system according to Embodiment 5 of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment 4, but the structural parameters are different. Please refer to the relevant description in Embodiment 4; it will not be repeated here.

[0118] Example 6

[0119] like Figure 13 The image shows an optical system according to Embodiment Six of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment Four, but the structural parameters are different. Please refer to the relevant description in Embodiment Four; it will not be repeated here.

[0120] Example 7

[0121] like Figure 14 As shown, an optical system according to Embodiment Seven of this application is described. Figure 14 A schematic diagram of the optical system of Embodiment Seven is shown.

[0122] like Figure 14 As shown, the optical system, from the imaging side to the light source side, sequentially includes the following components housed within the lens barrel: a first lens E1, a first spacer element P1, a first auxiliary spacer element P1b, a second lens E2, a second spacer element P2, a second auxiliary spacer element P2b, and a third lens E3. The second auxiliary spacer element P2b is located between the second spacer element and the third lens, and at least partially abuts against the light source side of the second spacer element.

[0123] In this embodiment, the first lens E1 has negative optical power, and its imaging side S1 and light source side S2 are both concave. The second lens E2 has positive optical power, its imaging side S3 is concave, and its light source side S4 is convex. The third lens E3 has positive optical power, its imaging side S5 is convex, and its light source side S6 is convex.

[0124] Table 6 shows the basic structural parameters of the optical system in Embodiment 7, where the units for radius of curvature, thickness / distance, and focal length are millimeters (mm). STO (not shown in the figure) is the aperture stop, which is located between the first lens and the second lens.

[0125] Table 6

[0126]

[0127]

[0128] In Example 7, all lenses are aspherical lenses, and the shape of the aspherical surface can be defined using, but is not limited to, formula (1) in Example 1. Table 7 below gives the higher-order coefficients of each aspherical mirror S1-S6 that can be used in Example 7.

[0129] Table 7

[0130] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 6.9970E-01 -2.8491E+00 9.4591E+00 -1.6228E+01 -1.9433E+01 2.0209E+02 -6.1190E+02 1.1137E+03 -1.3581E+03 S2 1.5279E+00 1.6378E+01 -5.8904E+02 9.7247E+03 -8.6792E+04 4.4258E+05 -1.2326E+06 1.5625E+06 -4.0145E+05 S3 -1.2277E+00 -2.6195E+01 1.7995E+03 -6.7611E+04 1.3497E+06 -1.3710E+07 5.5250E+07 0.0000E+00 0.0000E+00 S4 -3.9897E-01 2.3126E+00 -3.0657E+01 1.6194E+02 -4.0347E+02 3.5745E+02 0.0000E+00 0.0000E+00 0.0000E+00 S5 1.1628E-01 2.7175E+00 -3.8118E+01 2.6443E+02 -1.0702E+03 2.6792E+03 -4.1068E+03 3.5372E+03 -1.3148E+03 S6 -2.2705E-01 1.5127E-01 7.0859E+00 -4.4350E+01 1.4284E+02 -2.2298E+02 1.2963E+02 0.0000E+00 0.0000E+00

[0131] Figure 15 The on-axis chromatic aberration curve of the optical system of Embodiment 7 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the optical system. Figure 16 The astigmatism curves of the optical system of Embodiment 7 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 17 The magnification chromatic aberration curve of the optical system of Embodiment 7 is shown, which represents the degree to which the focal points of light of different wavelengths do not completely coincide.

[0132] according to Figures 15 to 17 It can be seen that the optical system given in Example 7 can achieve good imaging quality.

[0133] Example 8

[0134] like Figure 18 The image shows an optical system according to Embodiment 8 of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment 7, but the structural parameters are different. Please refer to the relevant description in Embodiment 7; it will not be repeated here.

[0135] Example 9

[0136] like Figure 19 The image shows an optical system according to Embodiment Nine of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment Seven, but the structural parameters are different. Please refer to the relevant description in Embodiment Seven; it will not be repeated here.

[0137] In summary, embodiments one through nine of the optical system satisfy the relationships shown in Table 8.

[0138] Table 8

[0139]

[0140]

[0141] Table 9 shows the optical parameters of the optical systems in Examples 1 to 9.

[0142] Table 9

[0143] Parameters / Examples one two three Four five six seven eight Nine f(mm) 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 0.38 f1(mm) -0.87 -0.87 -0.87 -0.72 -0.72 -0.72 -0.80 -0.80 -0.80 f2 (mm) 1.38 1.38 1.38 0.82 0.82 0.82 1.42 1.42 1.42 f3 (mm) 1.43 1.43 1.43 5.16 5.16 5.16 1.34 1.34 1.34 f12 (mm) 1.24 1.24 1.24 0.42 0.42 0.42 1.48 1.48 1.48 FOV (°) 130.00 130.00 130.00 135.00 135.00 135.00 137.00 137.00 137.00

[0144] Table 10 provides the parameters of each spacer element of the optical systems in Examples 1 to 9, in mm.

[0145] Table 10

[0146] Parameters / Examples one two three Four five six seven eight Nine d1s 2.0318 2.1318 2.2318 1.2836 1.2836 1.5147 1.3257 1.1024 0.8705 d1m 1.6458 2.7404 1.8404 1.6666 1.6766 1.6866 0.8794 0.6730 0.8705 D1s 2.6608 2.8647 2.9647 2.2972 2.0864 2.4267 2.6608 2.7608 3.1200 d2s 1.3233 1.4233 1.5599 1.4861 1.5134 1.5050 1.2266 1.3080 1.5050 d2m 1.7051 1.8051 1.8651 1.4861 1.5134 1.5020 1.6610 1.7512 1.7645 CP1 0.3879 0.3379 0.2879 0.9680 0.8180 0.6680 0.3313 0.2313 0.1050 EP12 0.5160 0.5660 0.5960 0.3904 0.3699 0.4505 0.5726 0.6726 0.7126 CP2 0.4130 0.3330 0.3030 0.0220 0.0220 0.0220 0.4800 0.3300 0.2600 d1bs 0.5054 0.5154 0.5254 1.3768 1.3007 1.2245 0.5054 0.5154 0.5254

[0147] This application also provides an imaging device, whose electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device such as a digital camera, or an imaging module integrated into a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical system described above.

[0148] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0149] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0150] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0151] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optical system, characterized in that, The optical system includes: The lens group has three lenses with optical power, and a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power are arranged sequentially from the imaging side to the light source side of the optical system. A plurality of spacer elements, wherein the first spacer element is located between the first lens and the second lens and at least partially abuts against the light source side of the first lens, and the second spacer element is located between the second lens and the third lens and at least partially abuts against the light source side of the second lens; The lens and the plurality of spacers are all housed within the lens barrel; Among them, the air gap between the first lens and the second lens on the optical axis of the optical system is the largest; The inner diameter d1m of the light source side of the first spacer element and the air gap T12 between the first lens and the second lens on the optical axis satisfy the following: 0.96≤d1m / T12≤3.15; The first lens and the second lens satisfy the following condition regarding the air gap T12 on the optical axis and the maximum thickness CP1 of the first spacer element: 1.17≤T12 / CP1≤6.

69.

2. The optical system according to claim 1, characterized in that, The inner diameter d1s of the imaging side of the first spacer element and the center thickness CT1 of the first lens on the optical axis satisfy the following condition: 2.08≤d1s / CT1≤7.

20.

3. The optical system according to claim 1, characterized in that, The effective focal length f1 of the first lens and the inner diameter d1s of the imaging side of the first spacer element satisfy the following condition: -2.57≤d1s / f1≤-1.

08.

4. The optical system according to claim 1, characterized in that, The radius of curvature R1 of the imaging side of the first lens and the radius of curvature R2 of the light source side of the first lens satisfy the following condition: -6.2964≤R1 / R2≤6.6283; the outer diameter D1s of the imaging side of the first spacer element and the radius of curvature R2 of the light source side of the first lens satisfy the following condition: 3.56≤D1s / R2≤6.

67.

5. The optical system according to claim 1, characterized in that, The combined focal length f12 of the first lens and the second lens, and the distance EP12 between the first spacer element and the second spacer element along the optical axis satisfy the following: 0.93≤f12 / EP12≤2.

59.

6. The optical system according to claim 1, characterized in that, The center thickness CT2 of the second lens on the optical axis and the distance EP12 from the first spacer element to the second spacer element along the optical axis satisfy the following condition: 1.05≤CT2 / EP12≤2.

05.

7. The optical system according to claim 1, characterized in that, The effective focal length f2 of the second lens and the inner diameter d2s of the imaging side of the second spacer element satisfy the following condition: 0.54≤f2 / d2s≤1.

16.

8. The optical system according to claim 1, characterized in that, The radius of curvature R3 of the imaging side of the second lens and the inner diameter d1m of the imaging side of the second spacer element satisfy the following: -2.09≤d1m / R3≤1.59; the radius of curvature R4 of the light source side of the second lens and the inner diameter d2s of the imaging side of the second spacer element satisfy the following: -2.77≤d2s / R4≤-1.

85.

9. The optical system according to claim 1, characterized in that, The center thickness CT2 of the second lens on the optical axis, the center thickness CT1 of the first lens on the optical axis, and the maximum thickness CP1 of the first spacer element satisfy the following condition: 0.56≤CT2 / (CT1+CP1)≤1.

43.

10. The optical system according to claim 1, characterized in that, The effective focal length f3 of the third lens and the inner diameter d2m of the light source side of the second spacer element satisfy the following condition: 0.76≤f3 / d2m≤3.47.

Images