Lens module and optical lens

Abstract

A lens module and an optical lens. The lens module comprises an eyepiece. The eyepiece comprises a first lens group and a second lens group which are arranged along the same optical axis on an exit pupil side, wherein the first lens group comprises a first lens (1) and a second lens (2), and the first lens group has a positive focal power; and the second lens group comprises a third lens (3) and a fourth lens (4), and the second lens group has a negative focal power. The eyepiece comprises a beam splitting element (7), a phase retarder (6), and a polarization reflective element (5), wherein the beam splitting element (7) is arranged on the side of the fourth lens (4) close to the exit pupil side, the polarization reflective element (5) is arranged on the side of the first lens (1) close to the exit pupil side, and the phase retarder (6) is located between the beam splitting element (7) and the polarization reflective element (5).

Description

Lens module and optical lens Technical Field

[0001] This application relates to the field of optical technology, and more specifically, to a lens module and an optical lens. Background Technology

[0002] As a crucial component of optical instruments such as telescopes and microscopes, the eyepiece's performance directly impacts the observer's visual experience and observation results. Traditional eyepiece designs often struggle to meet basic imaging requirements while simultaneously satisfying multiple demands such as miniaturization, lightweight design, and high image quality. In particular, with the continuous advancement of modern optical technology, higher requirements have been placed on eyepiece resolution, exit pupil diameter, and exit pupil distance. Summary of the Invention

[0003] The purpose of this application is to provide a new technical solution for a lens module and an optical lens.

[0004] In a first aspect, this application provides a lens module. The lens module includes an eyepiece;

[0005] The eyepiece includes a first lens group and a second lens group arranged along the same optical axis on the exit pupil side;

[0006] The first lens group includes a first lens and a second lens, and the first lens group has positive optical power;

[0007] The second lens group includes a third lens and a fourth lens, and the second lens group has negative optical power;

[0008] The eyepiece further includes a beam splitter, a phase retarder, and a polarization reflection element. The beam splitter is located on the side of the fourth lens near the exit pupil, the polarization reflection element is located on the side of the first lens near the exit pupil, and the phase retarder is located between the beam splitter and the polarization reflection element.

[0009] Optionally, the eyepiece satisfies: 6.5mm≤F1+F2+f≤7.1mm; where F1 is the focal length of the first lens group, F2 is the focal length of the second lens group, and f is the total focal length of the eyepiece.

[0010] Optionally, the eyepiece satisfies: 0.6 < (EP × ED) / (f × h) < 2.03; where EP is the exit pupil distance of the eyepiece, ED is the exit pupil diameter of the eyepiece, f is the total focal length of the eyepiece, and h is the image height of the eyepiece.

[0011] Optionally, the eyepiece satisfies: 0.6 < EP / (NA×h) < 2.03; where NA is the aperture of the eyepiece.

[0012] Optionally, the first mirror group satisfies: 4.74≤(f1+f2) / F1≤5;

[0013] Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, and F1 is the focal length of the first lens group.

[0014] Optionally, both the first lens and the second lens have positive optical power.

[0015] Optionally, the second mirror group satisfies: 4.34≤(f3+f4) / F2≤4.38;

[0016] Wherein, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and F2 is the focal length of the second lens group.

[0017] Optionally, both the third lens and the fourth lens have negative optical power.

[0018] Optionally, the first lens group satisfies: 2.29≤f1 / f2≤2.59, and the second lens group satisfies: 1.75≤f4 / f3≤1.81.

[0019] Optionally, the eyepiece satisfies: 4.35≤|(F1+F2) / TG|≤4.52;

[0020] Wherein, TG is the interval between the first lens group and the second lens group.

[0021] Optionally, the polarizing reflection element and the phase retarder are stacked on the surface of the first lens near the exit pupil side;

[0022] The beam splitter is disposed on the surface of the fourth lens near the exit pupil side.

[0023] Optionally, a polarizing element is provided on the surface of the fourth lens away from the exit pupil side.

[0024] Optionally, the first lens is a plano-convex spherical mirror, the second lens is a convex-concave aspherical mirror, the third lens is a concave-convex spherical mirror, and the fourth lens is a plano-convex spherical mirror.

[0025] Optionally, the eyepiece has an exit pupil distance EP of 15mm to 25mm, an exit pupil aperture ED of 25mm to 35mm, an aperture NA of 1.337 to 1.872, an image height h of 9.2mm to 13mm, and an FOV of 11.2° to 15.9°.

[0026] Optionally, the lens module further includes an objective lens system located on the side of the eyepiece away from the exit pupil.

[0027] Optionally, when the light received by the objective lens system is infrared light, the lens module further includes a display screen, which is located between the second lens group and the objective lens system.

[0028] Optionally, the display screen shows a dividing line mark;

[0029] The objective lens system includes an imaging device, which is electrically connected to the display screen. The target image captured by the imaging device can be displayed on the display screen.

[0030] Optionally, when the light received by the objective lens system is visible light, the objective lens system is located on the side of the second lens group away from the exit pupil side, and the objective lens system and the second lens group are spaced apart.

[0031] Secondly, this application provides an optical lens, the optical lens comprising:

[0032] The outer casing; and

[0033] The lens module as described in the first aspect.

[0034] The beneficial effects of this application are as follows:

[0035] The lens module provided in this application is a high-definition viewing and aiming lens module with a large exit pupil. Through the combination of a first lens group with positive optical power and a second lens group with negative optical power, and by introducing optical films such as beam-splitting elements, phase retarders, and polarization reflective elements into the module, excellent optical imaging performance is achieved, which is beneficial for improving image quality and clarity. In the lens module provided in this application, the large exit pupil design of the eyepiece not only improves user comfort but also expands the applicability of the eyepiece. Furthermore, this application achieves a miniaturized and lightweight design of the eyepiece. These advantages make the lens module of this application have broad application prospects in optical instruments such as telescopes and microscopes, and it has high practical value and market potential.

[0036] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0038] Figure 1 is a schematic diagram of the lens module provided in an embodiment of this application;

[0039] Figure 2 is a dot array diagram of the eyepiece in the lens module provided in the embodiment of this application;

[0040] Figure 3 is the MTF diagram of the eyepiece in the lens module provided in the embodiment of this application;

[0041] Figure 4 shows the distortion and field curvature of the eyepiece in the lens module provided in the embodiment of this application;

[0042] Figure 5 is a chromatic aberration diagram of the eyepiece in the lens module provided in the embodiment of this application.

[0043] Explanation of reference numerals in the attached drawings: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Polarizing reflector; 6. Phase retarder; 7. Beam splitter; 8. Polarizing element; 9. Objective lens system; 10. Display screen. Detailed Implementation

[0044] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0045] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0046] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0047] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0048] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0049] The lens module and optical lens provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0050] According to one embodiment of this application, a lens module is provided. Referring to FIG1, the lens module includes an eyepiece. The eyepiece includes a first lens group and a second lens group arranged along the same optical axis on the exit pupil side. The first lens group includes a first lens 1 and a second lens 2, and the first lens group has positive optical power. The second lens group includes a third lens 3 and a fourth lens 4, and the second lens group has negative optical power. The eyepiece further includes a beam splitter 7, a phase retarder 6, and a polarizing reflector 5. The beam splitter 7 is disposed on the side of the fourth lens 4 near the exit pupil side, the polarizing reflector 5 is disposed on the side of the first lens 1 near the exit pupil side, and the phase retarder 6 is located between the beam splitter 7 and the polarizing reflector 5.

[0051] The lens module proposed in this application is a high-definition viewing and aiming lens module that can also accommodate a large exit pupil, and has a wide range of applications. The following is a detailed description of its application scope.

[0052] The lens module of this application can be applied to telephoto lenses, especially those requiring high-resolution observation and a wide exit pupil to meet the needs of comfortable observation over extended periods. The lens module of this application provides an excellent visual observation experience.

[0053] In sports such as shooting and archery, the accuracy and clarity of the aiming lens are crucial. The lens module provided in this application, based on the high definition and precise optical design of its eyepiece, can serve as a suitable aiming lens. Furthermore, its large exit pupil design allows shooters to be more comfortable when aiming, reducing eye fatigue.

[0054] The lens module of this application is also suitable for photographic and video equipment that requires high resolution and clear imaging. It can complement macro lenses, telephoto lenses, or wide-angle lenses, helping to capture more detailed and clearer images.

[0055] The lens module provided in this application, as shown in Figure 1, comprises two main parts: an eyepiece and an objective lens. The eyepiece will be described first. Specifically, the eyepiece of this application includes two lens groups: a first lens group and a second lens group, both arranged along the same optical axis. The first lens group is located on the exit pupil side, i.e., the side closer to the observer's eye; while the second lens group is located on the side of the first lens group away from the exit pupil side, i.e., closer to the observed object or imaging plane. This design ensures effective transmission and focusing of light from the object side to the image side.

[0056] Please refer to Figure 1. The first lens group includes a first lens 1 and a second lens 2, and the first lens group has positive optical power, which can be used to converge light rays. The second lens group includes a third lens 3 and a fourth lens 4, and the second lens group has negative optical power, which can be used to correct aberrations and adjust the focal length. This combination of positive and negative optical power in the optical path helps to achieve high-quality imaging results.

[0057] In the eyepiece provided in this embodiment, the first lens group has positive optical power, while the second lens group has negative optical power. The combination of positive and negative optical power helps to correct chromatic aberration. Different wavelengths of light have different refractive indices when passing through a lens, which can cause a shift in the imaging position, i.e., chromatic aberration. By appropriately combining positive and negative optical power, light of different wavelengths can be more accurately focused at the same point after passing through the eyepiece, thereby reducing or eliminating chromatic aberration and improving image quality.

[0058] Distortion is a common problem in optical systems that causes image distortion. Combining positive and negative optical powers can effectively control distortion by varying the refraction and convergence of light, resulting in more realistic and accurate images.

[0059] Furthermore, by appropriately combining positive and negative optical powers, the number and complexity of lenses can be reduced while ensuring the optical performance of the eyepiece. This helps to reduce the size and weight of the eyepiece, improving its portability and ease of use.

[0060] In the eyepiece provided in this application, referring to Figure 1, the polarizing reflective element 5 is disposed on the side of the first lens 1 opposite to the second lens 2. The polarizing reflective element 5 has polarization properties and can reflect or transmit light in a specific direction, thereby realizing the control of the optical path.

[0061] The beam splitter 7 is disposed on the side of the fourth lens 4 near the third lens 3. The beam splitter 7 is, for example, a semi-transparent and semi-reflective film that can simultaneously transmit and reflect light.

[0062] The phase retarder 6 is disposed between the polarization reflecting element 5 and the beam splitting element 7. The phase retarder 6 can change the phase of the light rays, further realizing control over the optical path. Specifically, the phase retarder 6 is a quarter-wave plate.

[0063] It should be noted that the phase delayer 6 should be located between the beam splitter 7 and the polarization reflection element 5.

[0064] In this application, a folded optical path design is achieved by setting a polarizing reflection element 5 on the side of the first lens 1 away from the second lens 2, and setting a beam splitting element 7 (semi-transparent and semi-reflective film) on the side of the fourth lens 4 near the third lens 3, combined with a phase retarder 6 (quarter-wave plate) arranged between the two. This design not only makes the eyepiece structure more compact, but also reduces the length of the optical path, which helps to reduce light loss and improve image quality.

[0065] The eyepiece solution provided in this application, by dividing the eyepiece into a first lens group and a second lens group and employing a folding optical path design, makes the overall structure of the eyepiece more compact. This compact structural design not only reduces the size and weight of the eyepiece but also improves its portability, enabling the eyepiece to be more widely used in various handheld or portable observation and aiming devices.

[0066] It should be noted that the first lens group of the eyepiece provided in this application includes, but is not limited to, two lenses, and additional lenses may be added as needed. Similarly, the second lens group also includes, but is not limited to, two lenses, and the number of lenses can be flexibly adjusted as required.

[0067] The lens module provided in this application is a high-definition viewing and aiming lens module with a large exit pupil. Through the combination of a first lens group with positive optical power and a second lens group with negative optical power, and the introduction of optical films such as a beam splitter 7, a phase retarder 6, and a polarization reflector 5 into the module, excellent optical imaging performance is achieved, which is beneficial for improving image quality and clarity. In the lens module provided in this application, the large exit pupil design of the eyepiece not only improves user comfort but also expands the applicability of the eyepiece. Furthermore, this application achieves a miniaturized and lightweight design of the eyepiece. These advantages make the lens module of this application have broad application prospects in optical instruments such as telescopes and microscopes, and it has high practical value and market potential.

[0068] In some examples of this application, the eyepiece satisfies: 6.5mm≤F1+F2+f≤7.1mm; where F1 is the focal length of the first lens group, F2 is the focal length of the second lens group, and f is the total focal length of the eyepiece.

[0069] The eyepiece provided in this example satisfies a specific focal length relationship: 6.5mm ≤ F1 + F2 + f ≤ 7.1mm; where F1 is the focal length of the first lens group, F2 is the focal length of the second lens group, and f is the total focal length of the eyepiece. This focal length relationship is designed to optimize the optical performance of the eyepiece, ensuring high image clarity and a large exit pupil effect.

[0070] If the sum of focal lengths F1+F2+f is less than 6.5mm, it will lead to a decrease in image sharpness. Specifically, a focal length that is too short may cause light to not converge sufficiently when passing through the eyepiece, resulting in a blurry image on the retina and affecting the observer's visual experience.

[0071] If the sum of focal lengths F1+F2+f is less than 6.5mm, it may reduce the overall field of view of the eyepiece, limiting its application range. Furthermore, an excessively short sum of focal lengths may increase distortion and chromatic aberration in the eyepiece, especially in the peripheral areas, where these problems may be more pronounced and affect image quality.

[0072] If the sum of focal lengths, F1 + F2 + f, is greater than 7.1mm, this indicates that the focal length of the eyepiece may be too long. An excessively long focal length usually means the eyepiece requires more lens elements and a more complex structural design, which can increase the size and weight of the eyepiece, consequently increasing the size and weight of the entire lens module. Furthermore, an excessively long focal length may reduce the exit pupil diameter, affecting the observer's visual experience in low-light conditions and reducing observation comfort and accuracy.

[0073] In this example of the application, the eyepiece satisfies a specific focal length relationship: 6.5mm ≤ F1 + F2 + f ≤ 7.1mm. This focal length range is designed to balance multiple optical performance parameters, including image sharpness and exit pupil effect. Through focal length matching and lens design, it can be ensured that light converges optimally when passing through the eyepiece, forming a high-quality image while maintaining a large exit pupil diameter.

[0074] Thanks to the special design of the eyepiece, the eyepiece in this example of the application can maintain high resolution and clarity while also possessing excellent performance such as a large exit pupil and high contrast. In particular, the large exit pupil design improves user comfort and adaptability, while the high contrast design helps reduce glare and reflections, and improves the stereoscopic effect and realism of the image.

[0075] In some examples of this application, the eyepiece satisfies: 0.6 < (EP × ED) / (f × h) < 2.03; where EP is the exit pupil distance of the eyepiece, ED is the exit pupil diameter of the eyepiece, f is the total focal length of the eyepiece, and h is the image height of the eyepiece.

[0076] By controlling the proportional relationship between the eyepiece's exit pupil distance (EP) and exit pupil diameter (ED) and the eyepiece's total focal length (f) and image height (h), this example ensures that the eyepiece provides a large and clear field of view. It should be particularly noted that the eyepiece of this application is primarily intended for observation and aiming applications. Compared to optical devices such as virtual reality (VR), its field of view (FOV) is relatively small. However, the "larger field of view" emphasized here is relative to similar aiming lenses, reflecting a significant advantage in specific application areas. For example, the field of view of the eyepiece in this application is 11°–16°.

[0077] A larger exit pupil distance (EP) allows the observer to comfortably view the eyepiece from a greater distance, reducing eye strain. A larger exit pupil diameter (ED) allows more light to enter the eyepiece, improving image brightness and contrast, especially in low-light conditions. By controlling these proportional relationships, optimal image quality of the eyepiece can be ensured. Small variations in image height (h) have a limited impact on image quality, thus improving the accuracy and stability of observation.

[0078] The proportional relationship in this example allows the eyepiece to adapt to different observation conditions and observer needs. It maintains a clear image regardless of whether the observation is close-up or distant.

[0079] When the value of (EP×ED) / (f×h) is less than 0.6, it means that the eyepiece's exit pupil diameter (ED) and / or exit pupil distance (EP) are small relative to the eyepiece's total focal length (f) and image height (h). This may result in a limited field of view for the observer, preventing them from obtaining a sufficient range of observation. A smaller exit pupil diameter (ED) reduces the amount of light entering the eyepiece, thus affecting the brightness and contrast of the image. In low-light environments, this may cause the image to become blurry or difficult to discern. A smaller exit pupil distance (EP) may also require the observer to bring their eye closer to the eyepiece, which can increase eye fatigue and discomfort. Due to the limited field of view and reduced image sharpness, the observer's observation accuracy may be affected, especially in scenes requiring precise identification.

[0080] When the value of (EP×ED) / (f×h) is greater than 2.03, it means that the exit pupil diameter (ED) and / or exit pupil distance (EP) of the eyepiece are too large relative to the total focal length (f) and image height (h) of the eyepiece. This may cause the eyepiece to introduce more aberrations, thus affecting image sharpness. Furthermore, to meet larger exit pupil diameters (ED) and exit pupil distances (EP), the design and manufacturing of the eyepiece become more complex, which undoubtedly increases manufacturing costs and difficulty, and may also reduce the reliability of the entire lens module.

[0081] Therefore, a ratio of (EP×ED) / (f×h) less than 0.6 or greater than 2.03 can lead to a series of problems, including limited field of view, decreased image sharpness, reduced observer comfort, limited observation accuracy, increased aberrations, increased system complexity, limited observation range, and unnecessary weight and volume. Therefore, when designing high-definition, large exit pupil eyepieces, this ratio needs to be precisely controlled to ensure optimal eyepiece performance.

[0082] In some examples of this application, the eyepiece satisfies: 0.6 < EP / (NA×h) < 2.03; where NA is the aperture of the eyepiece.

[0083] In this example of the application, by controlling the proportional relationship between the exit pupil distance EP of the eyepiece and its aperture NA and image height h, the exit pupil distance can be optimized while ensuring sufficient light intake, so that the observer can observe the eyepiece from a more comfortable distance.

[0084] A larger exit pupil distance helps reduce eye fatigue and improve observation comfort.

[0085] The size of the aperture (NA) directly affects the amount of light entering the eyepiece. Under the proportional relationship provided in this example, by appropriately setting the aperture size, it can be ensured that the eyepiece provided in this application receives sufficient light, thereby improving the brightness and contrast of the image. This is especially important in low-light environments, significantly improving image visibility and recognizability.

[0086] Variations in image height (h) have a certain impact on image quality. By precisely controlling the ratio between EP and NA×h, the impact of image height variations on image quality can be reduced, thereby improving the accuracy and stability of observation.

[0087] When the value of EP / (NA×h) is less than 0.6, it means that the exit pupil distance EP is too small relative to a given aperture NA and image height h. This may cause the observer to need to place their eye very close to the eyepiece when using it, resulting in a narrow field of view and increased eye fatigue and discomfort. A small exit pupil distance EP may limit the angle and range of light entering the eyepiece, leading to insufficient light utilization. This will affect the brightness and contrast of the image, especially in low-light environments, potentially causing the image to become dim or difficult to observe. Due to the narrow field of view and insufficient light utilization, the observer's observation accuracy may be affected.

[0088] When the value of EP / (NA×h) is greater than 2.03, it means that the exit pupil distance EP is too large relative to a given aperture NA and image height h. This may cause the eyepiece to introduce more aberrations, thus affecting image sharpness and quality. Furthermore, to accommodate a larger exit pupil distance EP, the eyepiece design and manufacturing may require more complex structures and more materials. In addition, a larger exit pupil distance EP may increase the overall size of the eyepiece, thereby limiting the observer's head movement range and viewing angle.

[0089] Therefore, an EP / (NA×h) ratio less than 0.6 or greater than 2.03 can lead to a series of problems, including a narrow field of view, insufficient light utilization, limited observation accuracy, increased aberrations, increased structural complexity, and limited observation range. Thus, when designing high-definition, large exit pupil eyepieces, this ratio needs to be precisely controlled to ensure optimal eyepiece performance.

[0090] In some examples of this application, the first lens group satisfies: 4.74≤(f1+f2) / F1≤5; where f1 is the focal length of the first lens 1 and f2 is the focal length of the second lens 2.

[0091] In this example of the application, the focal length relationship of the first lens group in the eyepiece is: 4.74≤(f1+f2) / F1≤5. This ratio reflects the relationship between the sum of the focal lengths of the first lens 1 and the second lens 2 and the overall focal length of the first lens group.

[0092] f1: The focal length of the first lens 1, which determines the ability of the first lens 1 to converge or diverge light.

[0093] F2: The focal length of the second lens 2, which also affects the convergence or divergence of light.

[0094] F1: The focal length of the first lens group is the overall focal length of the combination of the first lens 1 and the second lens 2, reflecting the overall effect of the first lens group on light.

[0095] According to this example of the present application, by controlling the focal lengths of the first lens 1 and the second lens 2, and their proportional relationship with the overall focal length of the first lens group, the refraction and convergence of light can be optimized, thereby improving the clarity of the image.

[0096] By rationally designing the focal lengths of the first lens 1 and the second lens 2, as well as their proportional relationship with the focal length of the first lens group, distortion can be effectively controlled, making the image more accurate.

[0097] By rationally designing the focal lengths of the first lens 1 and the second lens 2, as well as their proportional relationship with the focal length of the first lens group, chromatic aberration can be reduced or eliminated, thereby improving image quality.

[0098] In some examples of this application, both the first lens 1 and the second lens 2 have positive optical power.

[0099] In this example of the application, the first lens 1 and the second lens 2 are designed to have positive optical power, and the first lens group they form also has positive optical power, while satisfying the above relationship: 4.74≤(f1+f2) / F1≤5; where f1 is the focal length of the first lens 1 and f2 is the focal length of the second lens 2.

[0100] In this example of the application, both the first lens 1 and the second lens 2 have positive optical power, meaning they can both converge light rays. The sum of the focal lengths of the first lens 1 and the second lens 2, together with the focal length of the first lens group, satisfies 4.74 ≤ (f1 + f2) / F1 ≤ 5. Because both the first lens 1 and the second lens 2 have positive optical power, they can jointly converge light rays, allowing the light rays to be focused more accurately at a single point after passing through the first lens group. This helps improve the sharpness of the image, especially in applications using high-definition large exit pupil eyepieces.

[0101] Positive power lenses can increase the convergence angle of light, thereby enhancing light collection capabilities. In the first lens group of this application, the combined action of two positive power lenses can further improve the light collection efficiency of the eyepiece, enabling better imaging results even under low-light conditions.

[0102] In some examples of this application, the second lens group satisfies: 4.34≤(f3+f4) / F2≤4.38; where f3 is the focal length of the third lens 3 and f4 is the focal length of the fourth lens 4.

[0103] According to the example provided in this application, 4.34≤(f3+f4) / F2≤4.38, this focal length ratio reflects the focal length control of the second lens group, which means that there is a balance between the combined focal length of the third lens 3 and the fourth lens 4 and the focal length of the second lens group.

[0104] In this example of the application, by controlling the ratio of the sum of the focal lengths of the third lens 3 and the fourth lens 4 to the focal length of the second lens group, the light transmission path can be optimized, thereby reducing aberrations and distortions and improving image sharpness. This ratio range may help ensure that light maintains proper diffusion as it passes through the eyepiece, thus providing a sufficiently large exit pupil while ensuring high sharpness, suitable for users with different interpupillary distances and pupil sizes.

[0105] The eyepiece provided in this application, in which the first lens group is typically responsible for collecting and focusing light, and its precise cooperation with the second lens group (especially f3 and f4 in this example of the application) can further ensure image quality.

[0106] When (f3+f4) / F2 < 4.34, it means that the combined focal length of the third lens 3 and the fourth lens 4 is relatively small compared to the overall focal length of the second lens group. This may result in an unoptimized refraction path for light passing through these two lenses, leading to increased aberrations and distortions. These aberrations and distortions directly affect the sharpness and accuracy of the image.

[0107] Furthermore, an excessively small ratio may result in insufficient light diffusion as it passes through the eyepiece, thus limiting the size of the exit pupil. The size of the exit pupil is crucial for the comfort and usability of the eyepiece. If the exit pupil is too small, it may prevent some users from using the eyepiece comfortably, especially for users with wide-set eyes or small pupils.

[0108] When (f3+f4) / F2 > 4.38, the combined focal length of the third lens 3 and the fourth lens 4 is relatively large compared to the overall focal length of the second lens group. This may cause light to diverge excessively when passing through these two lenses, making it difficult to refocus in subsequent optical elements to form a clear image. Furthermore, excessively diverged light may limit the field of view of the eyepiece. The user may not be able to see a sufficiently wide scene, thus affecting their observation efficiency and experience.

[0109] In some examples of this application, both the third lens 3 and the fourth lens 4 have negative optical power.

[0110] In this example of the application, both the third lens 3 and the fourth lens 4 are designed to have negative optical power, and the second lens group formed by their combination also has negative optical power. By appropriately designing lenses with negative optical power, aberrations introduced by other lenses, such as spherical aberration and chromatic aberration, can be corrected. Lenses with negative optical power help to expand the field of view of the eyepiece, allowing the observer to see a wider scene.

[0111] In some examples of this application, the first lens group satisfies: 2.29≤f1 / f2≤2.59, and the second lens group satisfies: 1.75≤f4 / f3≤1.81.

[0112] f1 and f2 represent the focal lengths of the first lens 1 and the second lens 2 in the first lens group, respectively. This ratio range ensures the balance of the two lenses in terms of optical power.

[0113] It should be noted that optical power is a measure of a lens's ability to refract light. A balanced combination of optical powers helps reduce aberrations and distortions, thereby improving image quality.

[0114] When f1 / f2 is too small, such as less than 2.29, the focal length of the first lens 1 is relatively small compared to the focal length of the second lens 2. This results in an unoptimized refraction path for light after passing through the first lens 1, preventing it from properly cooperating with the second lens 2, thus increasing aberrations and distortion and reducing image quality.

[0115] Furthermore, an excessively small ratio may result in insufficient focusing of light within the first lens group, preventing the light from reaching the ideal focusing state before entering the second lens group. This affects the processing of light by subsequent lenses, thereby impacting the imaging effect of the eyepiece.

[0116] When f1 / f2 is too large, such as greater than 2.59, the focal length of the first lens 1 is relatively large compared to the focal length of the second lens 2. This causes the light to be over-focused in the first lens group, resulting in excessive concentration of light when entering the second lens group, thus affecting the formation of a large and uniform field of view. An excessively large ratio may also cause aberrations and distortions. The light may be excessively deflected after passing through the first lens 1, making it difficult to coordinate with the second lens 2, thereby affecting image quality.

[0117] f3 and f4 represent the focal lengths of the third lens 3 and the fourth lens 4 in the second lens group, respectively. This ratio range ensures that the combination of these two lenses in terms of optical power can correct aberrations introduced by the first lens group or other lenses. By adjusting the ratio of f3 and f4, aberrations can be further reduced and image quality improved.

[0118] When f4 / f3 is too small, such as less than 1.75, the focal length of the fourth lens 4 is relatively small compared to the focal length of the third lens 3. This will result in insufficient correction capability of the fourth lens 4 for aberrations and distortions introduced by the third lens 3, thus affecting image quality. An excessively small ratio may lead to insufficient light diffusion in the second lens group, thereby limiting the field of view of the eyepiece.

[0119] When f4 / f3 is too large, such as greater than 1.81, the focal length of the fourth lens 4 is relatively large compared to the focal length of the third lens 3. This will cause excessive light diffusion in the second lens group, making it difficult to refocus the light to form a clear image. An excessively large ratio may also cause an increase in aberrations and distortions, because the light may be excessively deflected after passing through the fourth lens 4, making it difficult to coordinate with subsequent optical elements.

[0120] When the ratios of f1 / f2 and f4 / f3 exceed a given range, they may adversely affect the imaging quality and field of view of the eyepiece. Therefore, this application controls these ratio relationships during the design of the eyepiece to ensure that the eyepiece has excellent performance and user experience.

[0121] In some examples of this application, the eyepiece satisfies: 4.35≤|(F1+F2) / TG|≤4.52; where TG is the interval between the first lens group and the second lens group.

[0122] In this example of the application, F1 and F2 represent the focal lengths of the first lens group and the second lens group, respectively, and TG represents the interval between the first lens group and the second lens group, that is, the interval between the second lens 2 and the third lens 3. This formula describes the proportional relationship between the sum of the focal lengths of the two lens groups and the interval between them.

[0123] By controlling the ratio of the sum of the focal lengths of the two lens groups to their spacing, various aberrations can be effectively corrected, thereby improving the image quality of the eyepiece. The reduction of aberrations directly enhances image sharpness, allowing the observer to see more detailed images through the eyepiece.

[0124] Furthermore, optimizing the relationship between focal length and spacing helps to achieve a larger exit pupil diameter, which is especially important for observers who require a wide field of view or wear glasses.

[0125] In some examples of this application, referring to FIG1, the polarization reflection element 5 and the phase delayer 6 are disposed on the surface of the first lens 1 near the exit pupil side; the beam splitter 7 is disposed on the surface of the fourth lens 4 near the exit pupil side.

[0126] In this example of the application, the polarization reflection element 5 and the phase delayer 6 are disposed on the surface of the first lens 1 near the exit pupil side, while the beam splitter 7 is disposed on the surface of the fourth lens 4 near the exit pupil side.

[0127] The polarization reflective element 5 and the phase retarder 6 can be designed to be stacked to form a composite film, which facilitates the film application process. The phase retarder 6 is, for example, a quarter-wave plate.

[0128] The combined use of the polarization reflector 5 and the phase retarder 6 can effectively manage the polarization state of light. By placing them on the surface of the first lens 1 near the exit pupil, it can be ensured that the light is optimized before entering the observer's eye, thereby reducing adverse factors such as glare and ghosting, and improving the clarity and contrast of the observation.

[0129] The beam splitting element 7 is, for example, a semi-transparent and semi-reflective film, which can be disposed on the surface of the fourth lens 4 by means of coating or film application.

[0130] By placing the polarizing reflective element 5, the phase delayer 6, and the beam splitter 7 at specific positions on the first lens 1 and the fourth lens 4, not only is the optical effect optimized, but the integration of the eyepiece is also improved. This configuration makes the entire viewing lens more compact and lightweight, which is beneficial to improving the user experience and portability.

[0131] In some examples of this application, referring to FIG1, a polarizing element 8 is provided on the surface of the fourth lens 4 away from the exit pupil side.

[0132] The polarizing element 8 is a polarizing film, an optical thin film capable of selectively transmitting or reflecting light with a specific vibration direction. Introducing the polarizing element 8 into the eyepiece of this application enables polarization control of light, thereby improving the viewing experience and enhancing image contrast and clarity.

[0133] For example, the introduction of the polarizing element 8 can significantly reduce glare and reflected light from water surfaces, snow, smooth surfaces, etc., which often interfere with the observer's line of sight and reduce the visibility of the image.

[0134] For example, by filtering out unnecessary polarized light, the polarization element 8 can enhance the contrast between different objects in the image, making the observed target more prominent and easier to identify.

[0135] By placing the polarizing element 8 on the surface of the fourth lens 4 away from the exit pupil, it is ensured that light undergoes polarization control only after passing through the main optical components of the eyepiece, thus making more efficient use of the polarizing element's function. This design also reduces interference with the internal structure of the eyepiece, maintaining its compactness and lightweight nature.

[0136] In some examples of this application, referring to Figure 1, the first lens 1 is a plano-convex spherical mirror, the second lens 2 is a convex-concave aspherical mirror, the third lens 3 is a concave-convex spherical mirror, and the fourth lens 4 is a plano-convex spherical mirror.

[0137] The first lens 1 is a plano-convex spherical mirror: one side of the plano-convex spherical mirror is a plane, and the other side is a convex spherical surface. This design helps to correct astigmatism and field curvature while maintaining a wide field of view.

[0138] The second lens 2 is a convex-concave aspherical mirror: one side of the convex-concave aspherical mirror is convex, and the other side is concave. The aspherical design can more effectively correct various aberrations, such as spherical aberration and coma, thereby improving image sharpness. At the same time, the convex-concave design helps to control the refraction path of light, achieving more precise optical performance.

[0139] The third lens 3 is a concave-convex spherical mirror: one side of the concave-convex spherical mirror is convex, and the other side is concave. This design can correct aberrations to a certain extent while maintaining a relatively simple manufacturing process. The concave-convex spherical mirror helps to balance the refraction of light of different wavelengths and improve color reproduction.

[0140] The fourth lens 4 is a plano-convex spherical mirror: a plano-convex spherical mirror helps to further correct astigmatism and field curvature, and it can also provide additional focusing ability to ensure that light can be clearly imaged when it reaches the observer's eye.

[0141] The first lens 1 to the fourth lens 4 can all be made of glass.

[0142] By combining different types of lenses, especially using aspherical lenses, aberrations can be significantly reduced and image sharpness improved.

[0143] The lenses in this application offer flexibility in material selection, allowing for the use of either all-plastic or all-glass materials to meet diverse application needs and cost considerations. In terms of surface design, the lenses can be entirely aspherical, a design that more effectively corrects aberrations and improves image sharpness and quality. Furthermore, the concave-convex orientation of the lenses can be modified to accommodate different optical designs and performance requirements.

[0144] In some examples of this application, the eyepiece has an exit pupil distance EP of 15mm to 25mm, an exit pupil aperture ED of 25mm to 35mm, an aperture NA of 1.337 to 1.872, an image height h of 9.2mm to 13mm, and an FOV of 11.2° to 15.9°.

[0145] In this example of the application, the exit pupil distance EP of the eyepiece is 15mm to 25mm. This range allows the observer to clearly see the image in the eyepiece while maintaining a comfortable distance. A longer exit pupil distance helps reduce eye fatigue, especially during prolonged use, thus improving the comfort and duration of observation.

[0146] In this example of the application, the eyepiece has an exit pupil diameter (ED) of 25mm to 35mm, which provides sufficient light path, allowing the observer to obtain a wider field of view. This is particularly important in scenarios requiring wide-area observation, as it enhances the observer's ability to capture environmental information.

[0147] In this example of the application, the aperture NA of the eyepiece is set to 1.337–1.872. This range ensures sufficient light enters the eyepiece while avoiding glare or image distortion caused by excessive light. By controlling the aperture size, the eyepiece of this application can provide stable imaging effects under different lighting conditions and adapt to various complex environments.

[0148] In this example of the application, the image height h of the eyepiece is controlled within the range of 9.2 mm to 13 mm, ensuring the accuracy and clarity of the imaging. A reasonable image height setting helps reduce aberrations and distortion, improving image recognition and accuracy.

[0149] In this example of the application, the field of view (FOV) of the eyepiece is 11.2° to 15.9°, which, in the field of aiming lenses, allows the observer to observe a wider area without moving their head. However, this differs from the application of traditional folded optical paths in VR. This application achieves a large aperture effect within a small field of view.

[0150] By utilizing the aforementioned key parameters, the overall performance of the eyepiece has been significantly improved. Whether in terms of sharpness, contrast, brightness, or field of view, the eyepiece performs exceptionally well, meeting the needs of various high-precision and demanding applications.

[0151] In some examples of this application, referring to Figure 1, the lens module further includes an objective lens system 9 located on the side of the eyepiece away from the exit pupil.

[0152] In the lens module provided in this application embodiment, the objective lens system 9 is located on the side of the eyepiece away from the exit pupil side, and is able to receive light from the observed object.

[0153] By rationally designing the parameters of the objective lens system 9 (such as focal length, aperture, etc.), the light-gathering ability of the lens module can be significantly enhanced, thereby increasing the light transmission and brightness of the lens module.

[0154] The introduction of the objective lens system 9 further enhances the optical performance of the lens module. The objective lens system 9 can perform preliminary adjustments and optimizations to the light, reducing light loss and distortion during propagation, thereby improving the overall image quality and sharpness of the lens module. The effect of the objective lens system 9 is particularly pronounced in long-distance observation or low-light environments.

[0155] With the introduction of the objective lens system 9, the application areas of the lens module can be further expanded.

[0156] In some examples of this application, when the light received by the objective lens system 9 is infrared light, the lens module further includes a display screen 10, which is located between the second lens group and the objective lens system 9.

[0157] When the objective lens system 9 receives infrared light, the lens module can capture and image the infrared light. Infrared imaging technology can be applied to fields such as night observation and thermal imaging. With the addition of the display screen 10, the infrared imaging results can be displayed in real time, providing users with an intuitive observation experience.

[0158] In some examples of this application, the display screen 10 displays reticle markings; the objective lens system 9 includes an imaging device electrically connected to the display screen 10, and the target image captured by the imaging device can be displayed on the display screen 10.

[0159] The reticle markings displayed on the screen 10 provide the user with an intuitive reference frame. Users can use these reticles to more accurately locate the observation target, especially in scenarios requiring precise measurement or aiming; this design significantly improves the accuracy and precision of observations.

[0160] The electrical connection between the shooting device and the display screen 10 allows the target image captured by the shooting device to be displayed on the display screen 10 in real time. This real-time image display function facilitates immediate observation and judgment by the user.

[0161] With the reticle markings and real-time image display function on the display screen 10, users can observe more intuitively and conveniently. This design not only improves the practicality of the lens module but also enhances the user experience.

[0162] In some examples of this application, when the light received by the objective lens system 9 is visible light, the objective lens system 9 is located on the side of the second lens group away from the exit pupil side, and the objective lens system 9 and the second lens group are spaced apart.

[0163] When visible light passes through the objective lens system 9, it is focused and forms a clear image on a plane, which is the image plane of the objective lens system 9. Because there is a gap between the objective lens system 9 and the second lens group of the eyepiece, this gap provides the necessary space for the formation of the image plane.

[0164] According to this example of the application, the spacing allows light to travel a sufficient distance after passing through the objective lens system 9 for diffusion and focusing, thereby forming a sharper and clearer image plane. The sharpness and position of the image plane are crucial for subsequent imaging processes, as they directly affect the image quality seen by the observer through the eyepiece; the spacing also helps reduce optical interference between the objective lens system 9 and the second lens group, which could degrade image quality, and the spacing helps mitigate these adverse effects.

[0165] According to another embodiment of this application, an optical lens is provided, which includes a housing and a lens module as described above.

[0166] The eyepiece in this application is further described below through Examples 1 and 2.

[0167] Example 1

[0168] The eyepiece provided in this embodiment 1, as shown in Figure 1, includes a first lens group and a second lens group arranged along the same optical axis. The first lens group is located on the exit pupil side, and the second lens group is located on the focal plane side.

[0169] The first lens group includes a first lens 1 and a second lens 2. The first lens group has positive optical power, wherein both the first lens 1 and the second lens 2 have positive optical power.

[0170] The second lens group includes a third lens 3 and a fourth lens 4. The second lens group has negative optical power, wherein both the third lens 3 and the fourth lens 4 have negative optical power.

[0171] The first lens 1 is a plano-convex spherical mirror, the second lens 2 is a convex-concave aspherical mirror, the third lens 3 is a concave-convex spherical mirror, and the fourth lens 4 is a plano-convex spherical mirror. All of the first lenses 1 to the fourth lenses 4 are made of glass.

[0172] The eyepiece further includes a polarizing reflection element 5, a phase retarder 6, and a beam splitter 7. The polarizing reflection element 5 and the phase retarder 6 are disposed on the surface of the first lens 1 near the exit pupil side; the beam splitter 7 is disposed on the surface of the fourth lens 4 near the exit pupil side.

[0173] The focal length of the first lens group F1 is 98.81mm, and the focal length of the second lens group F2 is -139.1mm.

[0174] The total focal length f of the eyepiece is 46.8 mm, and the total system length of the eyepiece is 31 mm.

[0175] The eyepiece has an exit pupil distance EP of 15mm to 25mm and an exit pupil diameter ED of 25mm to 35mm.

[0176] The aperture NA of the eyepiece is 1.337-1.872;

[0177] The image height h of the eyepiece is 9.2mm to 13mm;

[0178] The field of view (FOV) of the eyepiece is 11.2° to 15.9°.

[0179] Table 1 shows the optical parameters of each lens in the eyepiece, as detailed below.

[0180] Table 1

[0181] Example 2

[0182] The eyepiece provided in this embodiment 2 has the same optical structure as that in embodiment 1 described above, as shown in Figure 1. The difference is:

[0183] The focal length of the first lens group is F1, which is 99.75 mm, and the focal length of the second lens group is F2, which is -139.5 mm.

[0184] The total focal length f of the eyepiece is 46.8 mm, and the total system length of the eyepiece is 30.9 mm.

[0185] The eyepiece has an exit pupil distance EP of 15mm to 25mm and an exit pupil diameter ED of 25mm to 35mm.

[0186] The aperture NA of the eyepiece is 1.337-1.872;

[0187] The image height h of the eyepiece is 9.2 mm to 12.4 mm;

[0188] The field of view (FOV) of the eyepiece is 11.2° to 15.1°.

[0189] The optical parameters of each lens in the eyepiece are detailed in Table 2.

[0190] Table 2

[0191] The optical performance of the eyepieces provided in Examples 1 and 2 is shown in Figures 2 to 5: Figure 2 is a schematic diagram of the dot plot, Figure 3 is a MTF curve, Figure 4 is a field curvature distortion diagram, and Figure 5 is a transverse chromatic aberration diagram.

[0192] Referring to Figure 2, the maximum value of the image point in the dot plot of the eyepieces provided in Examples 1 and 2 is less than 8 μm.

[0193] Referring to Figure 3, the eyepieces provided in Examples 1 and 2 have an MTF > 0.6 at 30 lp / mm.

[0194] Referring to Figure 4, the eyepieces provided in Examples 1 and 2 exhibit maximum distortion at field of view 1, with an absolute value of less than 8%, indicating very small distortion.

[0195] Referring to Figure 5, the eyepieces provided in Examples 1 and 2 have a maximum chromatic difference value of less than 16 μm.

[0196] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0197] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A lens module, characterized in that, Including the eyepiece; The eyepiece includes a first lens group and a second lens group arranged along the same optical axis on the exit pupil side; The first lens group includes a first lens (1) and a second lens (2), and the first lens group has positive optical power; The second lens group includes a third lens (3) and a fourth lens (4), and the second lens group has negative optical power; The eyepiece further includes a beam splitter (7), a phase retarder (6), and a polarization reflection element (5). The beam splitter (7) is located on the side of the fourth lens (4) near the exit pupil side. The polarization reflection element (5) is located on the side of the first lens (1) near the exit pupil side. The phase retarder (6) is located between the beam splitter (7) and the polarization reflection element (5).

2. The lens module according to claim 1, wherein, The eyepiece satisfies the following condition: 6.5mm≤F1+F2+f≤7.1mm; where F1 is the focal length of the first lens group, F2 is the focal length of the second lens group, and f is the total focal length of the eyepiece.

3. The lens module according to claim 1, wherein, The eyepiece satisfies: 0.6 < (EP × ED) / (f × h) < 2.03; where EP is the exit pupil distance of the eyepiece, ED is the exit pupil diameter of the eyepiece, f is the total focal length of the eyepiece, and h is the image height of the eyepiece.

4. The lens module according to claim 3, wherein, The eyepiece satisfies: 0.6 < EP / (NA×h) < 2.03; where NA is the aperture of the eyepiece.

5. The lens module according to claim 1, wherein, The first mirror group satisfies: 4.74≤(f1+f2) / F1≤5; Wherein, f1 is the focal length of the first lens (1), f2 is the focal length of the second lens (2), and F1 is the focal length of the first lens group.

6. The lens module according to claim 5, wherein, Both the first lens (1) and the second lens (2) have positive optical power.

7. The lens module according to claim 1, wherein, The second mirror group satisfies: 4.34≤(f3+f4) / F2≤4.38; Wherein, f3 is the focal length of the third lens (3), f4 is the focal length of the fourth lens (4), and F2 is the focal length of the second lens group. 8.The lens module according to claim 7, wherein, Both the third lens (3) and the fourth lens (4) have negative optical power. 9.The lens module according to claim 1, wherein, The first lens group satisfies: 2.29≤f1 / f2≤2.59, and the second lens group satisfies: 1.75≤f4 / f3≤1.

81. 10.The lens module according to claim 1, wherein, The eyepiece satisfies: 4.35≤|(F1+F2) / TG|≤4.52; Wherein, TG is the interval between the first lens group and the second lens group. 11.The lens module according to claim 1, wherein, The polarization reflection element (5) and the phase delayer (6) are stacked on the surface of the first lens (1) near the exit pupil side; The beam splitter (7) is disposed on the surface of the fourth lens (4) near the exit pupil side.

12. The lens module according to claim 11, wherein, A polarizing element (8) is provided on the surface of the fourth lens (4) away from the exit pupil side. 13.The lens module according to claim 1, wherein, The first lens (1) is a plano-convex spherical mirror, the second lens (2) is a convex-concave aspherical mirror, the third lens (3) is a concave-convex spherical mirror, and the fourth lens (4) is a plano-convex spherical mirror. 14.The lens module according to claim 1, wherein, The eyepiece has an exit pupil distance EP of 15mm to 25mm, an exit pupil aperture ED of 25mm to 35mm, an aperture NA of 1.337 to 1.872, an image height h of 9.2mm to 13mm, and an FOV of 11.2° to 15.9°.

15. The lens module according to claim 1, wherein, The lens module also includes an objective lens system (9), which is located on the side of the eyepiece away from the exit pupil.

16. The lens module according to claim 15, wherein, When the light received by the objective lens system (9) is infrared light, the lens module also includes a display screen (10), which is located between the second lens group and the objective lens system (9).

17. The lens module according to claim 16, wherein, The display screen (10) displays the dividing line markings; The objective lens system (9) includes an imaging device that is electrically connected to the display screen (10), and the target image captured by the imaging device can be displayed on the display screen (10). 18.The lens module according to claim 15, wherein, When the light received by the objective lens system (9) is visible light, the objective lens system (9) is located on the side of the second lens group away from the exit pupil side, and the objective lens system (9) and the second lens group are spaced apart.

19. An optical lens, characterized in that, include: shell; and The lens module as described in any one of claims 1-18.

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