Eyepiece and eyepiece optical system

Abstract

An embodiment of the present application provides an eyepiece and an eyepiece optical system; the eyepiece 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; the first lens group includes a first lens, a second lens, and a third lens arranged in sequence along the optical axis; the second lens group includes a fourth lens, a fifth lens, and a sixth lens arranged in sequence along the optical axis; the eyepiece satisfies the following: 0.049<n1 / f1+n2 / f2+n3 / f3+n4 / f4+n5 / f5+n6 / f6<0.08; wherein n1~n6 are the refractive indices of the first lens to the sixth lens, respectively, and f1~f6 are the focal lengths of the first lens to the sixth lens, respectively.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical technology, and more specifically, to an eyepiece and an eyepiece optical system. Background Art

[0002] Spotting lenses are widely used in scientific research, outdoor sports, and other fields. In recent years, with the advancement of technology, the performance requirements for spotting lenses have become increasingly stringent. Traditional spotting lenses often suffer from complex structures, high production costs, and poor imaging quality when meeting these requirements. Therefore, a new type of spotting lens is needed to address these issues. Summary of the Invention

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

[0004] In a first aspect, the present application provides an eyepiece. The eyepiece 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;

[0005] The first lens group includes a first lens, a second lens, and a third lens arranged in sequence along the optical axis;

[0006] The second lens group includes a fourth lens, a fifth lens, and a sixth lens arranged in sequence along the optical axis;

[0007] The eyepiece satisfies the following: 0.049<n1 / f1+n2 / f2+n3 / f3+n4 / f4+n5 / f5+n6 / f6<0.08; wherein n1 to n6 are the refractive indices of the first lens to the sixth lens, respectively, and f1 to f6 are the focal lengths of the first lens to the sixth lens, respectively.

[0008] Optionally, the eyepiece satisfies: 0.65<(EP×ED) / (f×h)<2.3; wherein 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.

[0009] Optionally, the fourth lens, the fifth lens and the sixth lens are cemented in sequence to form a cemented lens group.

[0010] Optionally, the fourth lens and the sixth lens both have positive optical power, and the fifth lens has negative optical power.

[0011] Optionally, the first lens, the second lens and the third lens all have positive optical power.

[0012] Optionally, the eyepiece satisfies: 0.042<(1 / F1)+(1 / F2)<0.08; wherein F1 is the focal length of the first lens group, and F2 is the focal length of the second lens group.

[0013] Optionally, the eyepiece satisfies: 1.19<F1 / f<1.3; wherein F1 is the focal length of the first lens group, and f is the total focal length of the eyepiece.

[0014] Optionally, the fourth lens is a biconvex lens, the fifth lens is a biconcave lens, and the sixth lens is a concave-convex lens.

[0015] Optionally, the first lens is a biconvex lens, the second lens is a plano-convex lens, and the third lens is a convex-concave lens.

[0016] Optionally, the exit pupil distance EP of the eyepiece is 35 mm to 45 mm, the exit pupil diameter ED of the eyepiece is 4 mm to 8 mm, and the F number of the eyepiece is 2.125 to 4.25.

[0017] Optionally, the image height of the eyepiece is 9.2 mm to 12.6 mm.

[0018] In a second aspect, the present application provides an eyepiece optical system. The eyepiece optical system comprises:

[0019] An eyepiece as described in the first aspect.

[0020] The beneficial effects of this application are:

[0021] The eyepiece provided in the embodiment of the present application is a sighting lens with a long exit pupil distance and a large aperture, which can solve the problems existing in the prior art. The eyepiece provided in the embodiment of the present application achieves excellent imaging effects at a long exit pupil distance through a specially designed combination of multiple lenses. At the same time, it has the characteristics of a large aperture and can provide clear imaging in low-light environments. The eyepiece provided in the embodiment of the present application provides a larger field of view and a comfortable visual observation experience based on the design of a long exit pupil distance. Therefore, the eyepiece of the present application has the effects of optimized imaging effects, a large aperture, a comfortable visual observation experience, and a wide range of application prospects, and can meet the observation needs of many fields such as scientific research and outdoor sports.

[0022] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0024] Figure 1 A schematic diagram of the structure of the eyepiece provided in an embodiment of the present application;

[0025] Figure 2 A dot array diagram of the eyepiece provided in an embodiment of the present application;

[0026] Figure 3 MTF diagram of the eyepiece provided in the embodiment of the present application;

[0027] Figure 4 Distortion and field curvature diagram of the eyepiece provided in the embodiment of the present application;

[0028] Figure 5 This is a diagram of vertical axial chromatic aberration of the eyepiece provided in an embodiment of the present application.

[0029] Description of reference numerals:

[0030] 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens. DETAILED DESCRIPTION

[0031] 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 arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0032] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0033] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0034] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0035] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0036] The eyepiece and the eyepiece optical system provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0037] According to one embodiment of the present application, an eyepiece is provided, see Figure 1The eyepiece 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; the first lens group includes a first lens 1, a second lens 2, and a third lens 3 arranged in sequence along the optical axis; the second lens group includes a fourth lens 4, a fifth lens 5, and a sixth lens 6 arranged in sequence along the optical axis; the eyepiece satisfies the following: 0.049<n1 / f1+n2 / f2+n3 / f3+n4 / f4+n5 / f5+n6 / f6<0.08; wherein n1~n6 are the refractive indices of the first lens 1 to the sixth lens 6, respectively, and f1~f6 are the focal lengths of the first lens 1 to the sixth lens 6, respectively.

[0038] The eyepiece proposed in the embodiments of the present application is a sighting lens with a long exit pupil distance and a large aperture, and has a wide range of applications. The following is a description of its application range.

[0039] The eyepiece provided in the embodiment of the present application has the characteristics of a long exit pupil distance and a large aperture, and can provide clear and stable imaging effects. Therefore, the eyepiece provided in the present application is very suitable for use in optical devices such as telescopes and riflescopes, and can meet the user's observation needs in complex environments.

[0040] In the field of scientific research, the imaging quality and stability of optical observation equipment are extremely high. The eyepiece of the embodiment of the present application, with its excellent optical performance, can be used in optical equipment / instruments such as scientific research telescopes and microscopes, helping researchers to obtain more accurate experimental data.

[0041] For outdoor sports enthusiasts, telescopes or sighting equipment with excellent optical performance are indispensable. The eyepiece of the embodiment of the present application has a wide field of view and a comfortable observation experience, which is very suitable for outdoor scenes.

[0042] In summary, the eyepiece provided in the embodiment of the present application has broad application prospects due to its long exit pupil distance, large aperture and excellent imaging quality, and can meet the usage needs of scientific research, outdoor sports and many other fields.

[0043] The eyepiece provided in the embodiment of the present application, from the perspective of its optical architecture, see Figure 1 The eyepiece consists of two lens groups: 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, closer to the observer's eye, while the second lens group is located on the focal plane side, closer to the observed object or the imaging surface. This layout ensures that light passes through the eyepiece along a predetermined path, resulting in a clear image.

[0044] Please continue to see Figure 1The first lens group mainly consists of the first lens 1, the second lens 2, and the third lens 3. These lenses work together to initially converge and adjust the light entering the eyepiece. The second lens group mainly consists of the fourth lens 4, the fifth lens 5, and the sixth lens 6. These lenses further focus and optimize the light to ensure the quality of the final image.

[0045] In the eyepiece optical architecture provided in the embodiments of this application, it should be noted that the specific number of lenses in the first and second lens groups is not absolutely fixed, but can be flexibly adjusted based on the actual application scenario requirements and design specifications. In other words, the number of lenses in these two lens groups can be appropriately increased or decreased based on the final imaging effect requirements.

[0046] The first lens group, located on the exit pupil side, primarily adjusts and controls the angle and path of light incident to ensure it enters the eyepiece. Therefore, depending on specific design requirements, the number of lenses in the first lens group can be adjusted or decreased to achieve the optimal optical effect.

[0047] The second lens group, located on the focal plane side, primarily focuses and optimizes light to achieve high-quality imaging. The number of lenses in the second lens group can be adjusted based on specific imaging requirements. By increasing or decreasing the number of lenses, performance parameters such as image quality, aperture size, and field of view can be further optimized.

[0048] The lens number adjustment mechanism allows the eyepiece of this application to better adapt to different application scenarios and usage requirements. Whether it is a telescope that requires high definition or an outdoor sports sighting device that requires a wide field of view, the number of lenses can be adjusted to meet specific performance requirements.

[0049] A key feature of the embodiments of the present application is that the eyepiece satisfies a specific relationship between the sum of the refractive index and the focal length, i.e., 0.049 < n1 / f1 + n2 / f2 + n3 / f3 + n4 / f4 + n5 / f5 + n6 / f6 < 0.08. This specific constraint relationship ensures that the optical performance of each lens can be matched and coordinated with each other, thereby achieving an overall optimized imaging effect. Specifically, the setting of this parameter in the present application can not only ensure the imaging quality, but also take into account the large aperture effect, and can also ensure the stability of the optical performance of the eyepiece, and control the manufacturing cost.

[0050] When n1 / f1+n2 / f2+n3 / f3+n4 / f4+n5 / f5+n6 / f6 is less than 0.049, it means that this parameter may be too small, which means that the refractive index of some lenses and their focal length are not ideally matched, which may result in the light not being fully converged and adjusted when passing through these lenses, thus affecting the final image quality.

[0051] Because the parameters n1 / f1+n2 / f2+n3 / f3+n4 / f4+n5 / f5+n6 / f6 are closely related to aperture performance, if these parameters are too small, the wide aperture effect may not be fully realized, which will affect the imaging quality of the eyepiece in low-light environments. In addition, this overly small parameter design may require more complex lens design or material selection, increasing the difficulty and cost of design and production.

[0052] When n1 / f1+n2 / f2+n3 / f3+n4 / f4+n5 / f5+n6 / f6 is greater than 0.08, it means that this parameter may be too large. This excessive parameter may also bring adverse effects, such as the increase of various aberrations (such as spherical aberration, chromatic aberration, etc.), which will seriously affect the clarity and accuracy of the imaging.

[0053] In application, controlling the parameter n1 / f1+n2 / f2+n3 / f3+n4 / f4+n5 / f5+n6 / f6 in the range of 0.049 to 0.08 can ensure that the overall performance of the eyepiece of the present application reaches the optimal state.

[0054] The eyepiece provided in the embodiment of the present application is shown in FIG. Figure 1 By rationally combining lenses and adjusting the refractive index and focal length of each lens, the entire eyepiece can maintain excellent imaging quality even at long exit pupil distances. This is due to the mutual matching and coordination of the optical performance of each lens. The eyepiece design provided in the embodiments of this application has the characteristics of a large aperture, which can provide clear imaging in low-light environments.

[0055] It should be noted that the design of long exit pupil distance enables the eyepiece to provide a larger field of view and a more comfortable visual observation experience during observation, which is especially suitable for scenarios of long-term use.

[0056] The eyepiece provided in the embodiment of the present application is a sighting lens with a long exit pupil distance and a large aperture, which can solve the problems existing in the prior art. The eyepiece provided in the embodiment of the present application achieves excellent imaging effects at a long exit pupil distance through a specially designed combination of multiple lenses. At the same time, it has the characteristics of a large aperture and can provide clear imaging in low-light environments. The eyepiece provided in the embodiment of the present application provides a larger field of view and a comfortable visual observation experience based on the design of a long exit pupil distance. Therefore, the eyepiece of the present application has the effects of optimized imaging effects, a large aperture, a comfortable visual observation experience, and a wide range of application prospects, and can meet the observation needs of many fields such as scientific research and outdoor sports.

[0057] In some examples of the present application, the eyepiece satisfies: 0.65<(EP×ED) / (f×h)<2.3; wherein 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.

[0058] In this example of the present application, a key mathematical inequality regarding the performance of the eyepiece is given: 0.65<(EP×ED) / (f×h)<2.3, where the meanings of the various symbols are as follows:

[0059] EP: It refers to the exit pupil distance of the eyepiece provided in this application, which refers to the distance from the rearmost surface of the eyepiece to the exit pupil (that is, the position where the observer's eyes should be placed).

[0060] ED: It refers to the exit pupil diameter of the eyepiece provided in this application. It is the diameter of the exit pupil, which will affect the brightness and width of the observer's field of view.

[0061] f: It refers to the total focal length of the eyepiece provided in this application, which is the distance from the optical center of the eyepiece to the imaging surface.

[0062] h: It refers to the image height of the eyepiece provided in this application, that is, the height of the imaging surface.

[0063] In this application, by adjusting the exit pupil diameter (ED), the observer's field of view can be expanded while ensuring sufficient field of view brightness. This is particularly important for sighting lenses, which need to ensure a clear and bright field of view under various lighting conditions.

[0064] The inequality provided in this example also takes into account the eyepiece's focal length (f) and image height (h), two parameters that directly affect image clarity and field of view. By calculating and adjusting these parameters, stable image quality can be maintained across different focal lengths and image heights, thereby enhancing the eyepiece's usability and performance.

[0065] The inequality provided in this example provides a comprehensive set of design parameters, helping technicians balance various performance indicators when designing eyepieces, such as field of view brightness, field of view range, image quality, and exit pupil distance. By optimizing these parameters, it is possible to create a sighting lens with excellent performance.

[0066] When (EP × ED) / (f × h) is less than 0.65, the exit pupil diameter (ED) is small relative to the other parameters, which can result in insufficient field of view brightness. In applications such as spotting lenses, a bright field of view is crucial for accurate observation and aiming. Insufficient brightness can make it difficult for the observer to see the target clearly in low-light conditions.

[0067] A smaller exit pupil diameter may also limit the observer's field of view, resulting in only a limited area near the target being visible during observation, which may affect the comprehensiveness and accuracy of observation.

[0068] In addition, for observation lenses that need to be worn for a long time, a smaller exit pupil distance (EP) may cause eye discomfort or fatigue to the wearer, especially for observers wearing glasses, who may need more frequent adjustments to maintain a clear field of view.

[0069] When (EP×ED) / (f×h) is greater than 2.3, the exit pupil diameter is too large relative to other parameters, which may cause imaging distortions such as barrel distortion or pincushion distortion. These distortions affect the observer's accurate judgment of the object's shape and size.

[0070] Excessively large exit pupil diameters can also increase the likelihood of flare and glare, especially near strong light sources. Flare and glare can interfere with the observer's vision and reduce observation accuracy.

[0071] In addition, under certain focal length and image height conditions, an excessively large ratio may lead to unstable imaging performance, such as focus drift or image blur, which will affect the applicability and performance of the eyepiece.

[0072] When the ratio of (EP×ED) / (f×h) falls between 0.65 and 2.3, the exit pupil diameter (ED) is relatively moderate, ensuring that the observer obtains sufficient field of view brightness under different lighting conditions. A moderate exit pupil diameter also helps to expand the observer's field of view, allowing the observer to have a more comprehensive understanding of the surrounding environment, thereby improving the accuracy and safety of observation. Through reasonable design, the eyepiece of the present application can provide the observer with a comfortable wearing experience while maintaining a clear field of view. This helps to reduce eye fatigue and discomfort, and improve the observer's satisfaction with use.

[0073] The ratio range provided in this example takes into account the eyepiece's total focal length and image height, two parameters that directly impact image clarity and field of view. Through precise calculation and adjustment, stable image quality can be maintained under varying focal lengths and image heights, thereby enhancing the eyepiece's applicability and performance. Because this ratio range balances various performance indicators, the eyepiece of this application is adaptable to a variety of application scenarios and observation needs. This increases the eyepiece's market competitiveness and scope of application.

[0074] In some examples of this application, see Figure 1 The fourth lens 4, the fifth lens 5 and the sixth lens 6 are glued together in sequence to form a glued lens group.

[0075] In this example, the cemented design of the fourth lens element 4, the fifth lens element 5, and the sixth lens element 6 helps correct chromatic aberration across wavelengths from visible light to infrared light, improving image quality. The cemented lens assembly also effectively controls various aberrations, such as spherical aberration, coma, and astigmatism. These aberrations are key factors affecting image clarity and sharpness.

[0076] Cemented lens designs offer greater mechanical strength than single lenses because the cementing material binds the lenses together tightly, creating a more robust overall structure.

[0077] In actual applications, sighting lenses may be affected by external factors such as vibration and impact. The design of the cemented lens group helps to improve the lens's impact resistance and stability.

[0078] Lenses made of different materials have different coefficients of thermal expansion as the temperature fluctuates. By properly selecting and combining these materials, the bonded lens assembly can maintain relatively stable optical performance despite temperature fluctuations. This is particularly important for sighting lenses that operate in both high and low temperature environments.

[0079] Furthermore, considering manufacturing costs and efficiency, the cemented lens assembly is processed and assembled as a single unit during the manufacturing process, which helps simplify the assembly process and improve production efficiency. In contrast, if a single lens design is used, the position and angle of each lens must be assembled and adjusted individually, which undoubtedly increases manufacturing difficulty and cost.

[0080] In some examples of the present application, the fourth lens 4 and the sixth lens 6 both have positive refractive power, and the fifth lens 5 has negative refractive power.

[0081] In this example of the present application, the fourth lens element 4 and the sixth lens element 6 both have positive refractive power, while the fifth lens element 5 has negative refractive power. This design produces significant technical benefits in the eyepiece of the present application, particularly when these three lenses are included as part of the second lens group (on the focal plane side). The following is a detailed analysis of this design.

[0082] Positive lenses, such as the fourth and sixth lenses, 6, help converge light, while negative lenses, such as the fifth lens 5, located between the two positive lenses, diverge light. By combining these three lenses in positive, negative, and positive configurations, the focal length of the second lens group, and thus the entire eyepiece, can be adjusted.

[0083] This design in this example of the present application helps correct various aberrations, such as spherical aberration, coma, and field curvature, thereby improving image quality. In particular, the negative optical power of the fifth lens element 5 effectively balances the aberrations introduced by the positive optical power lens element, thereby better controlling the aberrations of the entire second lens group.

[0084] In the eyepiece of this application, the combined design of positive and negative optical powers in the second lens group also helps achieve the optical effects of a large aperture and a long exit pupil distance. The large aperture increases the amount of light passing through the eyepiece, enabling bright images even in low-light environments. The long exit pupil distance helps reduce the distance between the eyepiece and the observer's eyes, improving viewing comfort.

[0085] In this example, the positive refractive power of the fourth and sixth lenses 4 and 6 converges more light, while the negative refractive power of the fifth lens 5 adjusts focal length and corrects aberrations, collectively achieving the design goals of a large aperture and a long exit pupil distance. Furthermore, the compact design of the fourth through sixth lenses 4 through 6, as part of the second lens group, contributes to the miniaturization of the entire eyepiece.

[0086] In some examples of the present application, the first lens 1 , the second lens 2 , and the third lens 3 all have positive refractive power.

[0087] In the eyepiece of the embodiment of the present application, the first lens group includes three lenses, namely a first lens 1, a second lens 2 and a third lens 3, which are sequentially arranged along the same optical axis.

[0088] In this example of the present application, all three lenses in the first lens group have positive optical power. That is, the first lens 1 through the third lens 3 are all positive lenses. Working together, they effectively converge light from the object being observed. This design helps increase light throughput through the eyepiece, ensuring clear images even in low-light conditions. Furthermore, the combination of positive optical power lenses helps correct various aberrations, which is crucial for improving image quality.

[0089] In this example, the first and second lens groups work in synergy. When the positive-power lens in the first lens group is paired with the three lenses in the second lens group (particularly the fourth lens 4 with positive power, the fifth lens 5 with negative power, and the sixth lens 6 with positive power), more complex and precise optical performance control can be achieved.

[0090] The negative power of the fifth lens element 5 helps balance the positive power introduced by the first lens group, the fourth lens element 4, and the sixth lens element 6, thereby further correcting aberrations and improving image quality. This design also helps achieve a long exit pupil distance and a large aperture.

[0091] The long exit pupil distance design helps reduce the distance between the eyepiece and the observer's eyes, improving viewing comfort. The positive power lens assembly in the first lens group converges light, providing the foundation for this long exit pupil distance design. When combined with the lenses in the second lens group, the entire eyepiece optical path is optimized, further ensuring the realization of a long exit pupil distance.

[0092] A large aperture increases the amount of light passing through a lens, enabling bright images even in low-light conditions. The positive power lens combination in the first lens group provides the foundation for achieving a large aperture by focusing more light. Simultaneously, the lens design in the second lens group also takes the need for a large aperture into account, achieving this goal through precise power distribution and aperture design.

[0093] In some examples of the present application, the eyepiece satisfies: 0.042<(1 / F1)+(1 / F2)<0.08; wherein F1 is the focal length of the first lens group, and F2 is the focal length of the second lens group.

[0094] The eyepiece proposed in this example satisfies the requirement for a constrained and rationally designed focal length ratio between the first and second lens groups. By controlling the reciprocal of the sum of the focal lengths of these two lens groups (i.e., (1 / F1) + (1 / F2)) within the range of 0.042 to 0.08, more precise optical performance control can be achieved. This rational focal length ratio facilitates better correction of various aberrations.

[0095] Specifically, when the focal length ratio of the first lens group and the second lens group meets the above conditions, the optical power and aberration correction capability of each lens can be more effectively balanced, thereby obtaining a clearer image.

[0096] Furthermore, this focal length ratio helps improve lens resolution. Resolution is a key indicator of lens imaging quality. By precisely controlling the focal length ratio, the eyepiece can better preserve object details during imaging, thereby improving resolution.

[0097] The design of a long exit pupil distance helps improve viewing comfort. In this example of the present application, by optimizing the focal length ratio, it is possible to ensure that the first lens group and the second lens group maintain a certain balance when converging light, thereby achieving the design goal of a long exit pupil distance.

[0098] The large aperture design can increase the amount of light transmitted by the eyepiece of this application, allowing for bright images even in low-light environments. The optimization of the focal length ratio provided in this example of this application helps ensure that the eyepiece of this application maintains a large aperture without sacrificing too much image quality. This allows the eyepiece to maintain good imaging effects even in low-light environments.

[0099] Optimizing the focal length ratio also helps improve the stability of the entire eyepiece. When the focal length ratio of the first lens group and the second lens group is maintained within a reasonable range, the eyepiece can maintain stable optical performance under various environmental conditions.

[0100] When (1 / F1) + (1 / F2) is less than 0.042, it means that the focal lengths of the first and second lens groups are relatively long, or the difference between their focal lengths is relatively large. This may result in a decrease in light convergence. This is because a longer focal length means that light is less able to converge as it passes through the eyepiece, which reduces the amount of light passing through the eyepiece, affecting the brightness and clarity of the image.

[0101] The increase in focal length is accompanied by a reduction in the field of view, which may limit the observation range of the eyepiece and hinder the user from capturing a wider scene.

[0102] In addition, a longer focal length may require the eyepiece to have a larger physical size, which is not conducive to achieving lightweight and miniaturization of the lens.

[0103] When (1 / F1) + (1 / F2) is greater than 0.08, it means that the focal lengths of the first and second lens groups are relatively short, or the difference between their focal lengths is relatively small. Short focal lengths can cause light to converge excessively when passing through the eyepiece, resulting in an overly strong converging effect. This can cause image distortion or other optical problems. Shortened focal lengths also increase the occurrence of various aberrations, which can affect image quality.

[0104] Furthermore, in order to achieve a shorter focal length while maintaining high-quality imaging, higher-precision manufacturing processes and materials may be required, which will increase the manufacturing cost of the eyepiece.

[0105] In summary, the condition of 0.042 < (1 / F1) + (1 / F2) < 0.08 plays a crucial role in the design of the eyepiece of this application. It ensures that the eyepiece can effectively correct aberrations and maintain stability while maintaining sufficient light throughput and field of view. When (1 / F1) + (1 / F2) exceeds the range constrained in this example of this application, it will lead to problems such as weakened light convergence ability, limited field of view, increased difficulty in aberration correction, and reduced structural compactness (less than 0.042), or it will lead to problems such as excessive light convergence, increased aberrations, reduced eyepiece stability, and increased manufacturing costs (greater than 0.08).

[0106] In some examples of the present application, the eyepiece satisfies: 1.19<F1 / f<1.3; wherein F1 is the focal length of the first lens group, and f is the total focal length of the eyepiece.

[0107] In this example of the present application, the ratio of 1.19 < F1 / f < 1.3 plays a crucial role in the design of the eyepiece, ensuring that the eyepiece maintains a sufficient field of view, light focusing capability, and image quality while achieving good aberration correction and optical stability. In this example of the present application, optimal optical performance is achieved by controlling the ratio of the focal length of the first lens group to the total focal length of the eyepiece.

[0108] When the ratio F1 / f is less than 1.19, it means that the focal length F1 of the first lens group is shorter than the total focal length f of the entire eyepiece. A shorter focal length of the first lens group may increase distortion at the edges of the field of view, affecting the accuracy and realism of the image. A shorter focal length of the first lens group may also result in insufficient light convergence as it passes through the eyepiece, resulting in reduced image brightness and contrast. A shorter focal length of the first lens group may also increase aberrations, thereby affecting image quality.

[0109] When the ratio F1 / f is greater than 1.3, this means that the focal length F1 of the first lens group is longer than the total focal length f of the entire eyepiece. This longer focal length of the first lens group may reduce the field of view of the entire eyepiece, hindering the user from capturing a wider scene. It also hinders the lightweight and compact design of the eyepiece.

[0110] In some examples of this application, see Figure 1 The fourth lens 4 is a biconvex lens, the fifth lens 5 is a biconcave lens, and the sixth lens 6 is a concave-convex lens.

[0111] In the eyepiece of the present application, the second lens group includes a fourth lens 4, which is adjacent to and spaced apart from the third lens 3 in the first lens group. The fourth lens 4 is a biconvex lens. The biconvex lens design means that the lens has a convex shape on both surfaces, which can be used to enhance the lens's positive optical power. In the eyepiece of the present application, the positive optical power helps focus light onto the focal plane, thereby improving image clarity.

[0112] By using a biconvex lens as the fourth lens, the aberrations introduced by the first lens group can be further corrected. In addition, it helps to improve the overall light throughput of the eyepiece, allowing it to better capture images in low-light environments.

[0113] In the eyepiece of the present application, the second lens group includes a fifth lens 5, which is a biconcave lens. A biconcave lens has a concave shape on both surfaces, which can be used to provide negative optical power. In the overall eyepiece design, the negative optical power lens helps to disperse light, thereby balancing the focusing effect introduced by the positive optical power lens.

[0114] The fifth lens 5, as a biconcave lens, can further correct aberrations such as field curvature and distortion. By introducing an appropriate amount of negative optical power, it can also help adjust the overall focal length of the entire eyepiece, ensuring that the image can be accurately focused on the focal plane.

[0115] The eyepiece of the present application also includes a sixth lens 6 in the second lens group. This sixth lens 6 is a meniscus lens. A meniscus lens has one convex surface and the other concave surface, which allows it to provide a combination of positive and negative optical powers. As a meniscus lens, the sixth lens can further fine-tune the imaging performance of the eyepiece. Furthermore, it helps improve the contrast and resolution of the lens, resulting in clearer and sharper images.

[0116] In this example of the present application, the design of each lens of the second lens group achieves excellent imaging performance of a long exit pupil distance and large aperture viewing lens through precise optical focal length distribution and surface shape combination.

[0117] In some examples of this application, see Figure 1 The first lens 1 is a biconvex lens, the second lens 2 is a plano-convex lens, and the third lens 3 is a convex-concave lens.

[0118] The eyepiece provided in the embodiment of the present application is shown in FIG. Figure 1 The first lens group includes a first lens 1 to a third lens 3.

[0119] The first lens 1 is a biconvex lens. The biconvex lens design features a convex shape on both surfaces, thereby enhancing the lens's positive focal power. In the eyepiece provided herein, positive focal power is a key factor in focusing light onto the focal plane. Using the first lens 1 as a biconvex lens efficiently collects and focuses incident light, improving the eyepiece's luminous flux and imaging quality.

[0120] The second lens 2 is a plano-convex lens, with one surface flat and the other convex. This design provides a certain degree of positive optical power while reducing weight and cost. As a plano-convex lens, the second lens 2 further corrects aberrations introduced by the first lens 1 while maintaining the overall optical power balance of the eyepiece. Its flat surface also simplifies processing and assembly.

[0121] The third lens element 3 is a convexo-concave lens, with one surface convex and the other concave. This allows it to provide a combination of positive and negative optical power. This design facilitates more complex aberration correction in the eyepiece. As a convexo-concave lens, the third lens element 3 can fine-tune the imaging performance of the eyepiece, correcting higher-order aberrations such as chromatic aberration and field curvature by adjusting its surface curvature and thickness. It also helps balance the optical power of the first lens group, ensuring that the image is accurately focused on the focal plane.

[0122] In the eyepiece of this application, the second lens group includes the fourth lens 4 through the sixth lens 6. As previously analyzed, the biconvex design of the fourth lens 4 enhances positive optical power, further corrects aberrations, and improves light throughput. The fifth lens 5 is a biconcave lens with negative optical power, which helps disperse light and correct field curvature and distortion. The sixth lens 6 is a concave-convex lens that can fine-tune the imaging performance of the eyepiece, correct for higher-order aberrations, and improve contrast and resolution.

[0123] By combining the first lens 1 to the third lens 3 (first lens group) and the fourth lens 4 to the sixth lens 6 (second lens group), a high-efficiency eyepiece can be formed. By precisely designing the optical power and surface shape of each lens, as well as the matching between them, various aberrations can be corrected and the luminous flux, contrast and resolution of the eyepiece can be improved. In addition, this design also helps to achieve the effects of long exit pupil distance and large aperture. The long exit pupil distance allows the eyepiece to maintain clear imaging over a wider viewing angle, while the large aperture allows the eyepiece to better capture images in low-light environments. These characteristics give the eyepiece excellent imaging performance in a variety of application scenarios.

[0124] Optionally, in the present application, the first lens 1 to the sixth lens 6 are all glass spherical lenses. Spherical lenses can provide stable imaging performance. Furthermore, the manufacturing process of spherical lenses is relatively simple, with high production efficiency, making them suitable for large-scale production. Glass materials have excellent light transmittance and refractive index stability, which enables lenses made of glass to provide clear, high-quality images.

[0125] Of course, the first lens 1 to the sixth lens 6 may also be partially or entirely made of plastic material. The first lens 1 to the sixth lens 6 may all be aspherical lenses.

[0126] In some examples of the present application, the exit pupil distance EP of the eyepiece is 35 mm to 45 mm, the exit pupil diameter ED of the eyepiece is 4 mm to 8 mm, and the F number of the eyepiece is 2.125 to 4.25.

[0127] In this example of the present application, the pupil distance (EP) is 35mm to 45mm. This design enhances wearing comfort. The pupil distance refers to the distance from the observer's eye to the exit pupil plane of the eyepiece. This range accommodates most people's eye distances, including those wearing glasses, providing a comfortable viewing experience.

[0128] The eyepiece provided in this application has a longer pupil distance. This longer pupil distance allows the observer to have a more comfortable distance between their eyes and the eyepiece when using the eyepiece, reducing eye fatigue during prolonged observation. This is particularly important for applications that require prolonged use of the sighting lens (such as shooting, telescope observation, etc.). As the pupil distance increases, the observer's field of view through the eyepiece also expands accordingly. This is a significant advantage for sighting tasks that require a wide field of view.

[0129] In this example, the exit pupil diameter (ED) is 4mm to 8mm. This design ensures sufficient field of view brightness. The size of the exit pupil directly affects the amount of light entering the observer's eyes. Within this range, the exit pupil diameter ensures a sufficiently bright field of view under various lighting conditions, thereby improving observation clarity.

[0130] The eyepiece provided in this application has a larger exit pupil diameter. A larger exit pupil diameter helps expand the observer's field of view, enabling a more comprehensive understanding of the surrounding environment and improving the accuracy and safety of observation.

[0131] In this example, the eyepiece has an F-number of 2.125 to 4.25. This design balances image quality and light throughput. The F-number is the ratio of the eyepiece focal length to the exit pupil diameter, reflecting the eyepiece's light transmission and image quality. Within this range, the F-number balances light throughput and image clarity, enabling the eyepiece to provide high-quality images under a variety of lighting conditions.

[0132] By adjusting the F-number, you can adapt to different observation needs and scenes. For example, a smaller F-number (i.e., greater light transmission) is suitable for bright environments, while a larger F-number (i.e., less light transmission but higher image clarity) is suitable for dim environments.

[0133] The eyepiece parameter range in this example of the present application, namely, the exit pupil distance EP is 35mm to 45mm, the exit pupil diameter ED is 4mm to 8mm, and the eyepiece F number is 2.125 to 4.25, which together achieve the following technical effects:

[0134] (1) Improve wearing comfort and adaptability: Through reasonable exit pupil distance and exit pupil diameter design, the eyepiece provided in this application can be suitable for a wider range of people and usage scenarios.

[0135] (2) Ensure the brightness and clarity of the field of view: Under different lighting conditions, it can provide a sufficiently bright field of view and clear imaging effects.

[0136] (3) Optimizing image quality and light throughput: By balancing the F number, the best match between image quality and light throughput is achieved to meet diverse observation needs.

[0137] The above-mentioned technical effects jointly improve the overall performance and user experience of the eyepiece, making the eyepiece have broad application prospects in the field of observation and aiming.

[0138] In some examples of the present application, the image height of the eyepiece is 9.2 mm to 12.6 mm.

[0139] Image height determines the size of the image presented by the eyepiece. Within this range, the image height ensures a sufficiently wide field of view for the observer, providing a more comprehensive understanding of the surrounding environment and improving observation efficiency. A larger image height results in a clearer and more detailed image, making it easier for the observer to discern target details and enhancing the observation experience.

[0140] When designing an eyepiece, a trade-off needs to be made between image quality and image height. An image height within this range ensures that the eyepiece provides a sufficiently large field of view while maintaining good image quality.

[0141] As a crucial component of the sighting lens, the eyepiece's performance directly impacts the overall performance of the lens. A reasonable image height design can improve the system's overall performance, including key indicators like resolution and contrast.

[0142] The eyepiece of the present application is further described below through Example 1 and Example 2.

[0143] Example 1

[0144] The eyepiece provided in this embodiment 1 is shown in FIG. Figure 1 , comprising a first lens group and a second lens group arranged along the same optical axis, wherein the first lens group is located on the exit pupil side, and the second lens group is located on the focal plane side;

[0145] The first lens group includes a first lens 1, a second lens 2, and a third lens 3, wherein the first lens 1, the second lens 2, and the third lens 3 all have positive refractive power;

[0146] The second lens group includes a fourth lens 4, a fifth lens 5, and a sixth lens 6, wherein the fifth lens 5 has a negative optical power, and the fourth lens 4 and the sixth lens 6 both have positive optical power; wherein the fourth lens 4 and the third lens 3 are disposed adjacent to each other;

[0147] The first lens 1 is a biconvex lens, the second lens 2 is a plano-convex lens, the third lens 3 is a convex-concave lens, the fourth lens 4 is a biconvex lens, the fifth lens 5 is a biconcave lens, and the sixth lens 6 is a concave-convex lens. The first lens 1 to the sixth lens 6 are glass spherical mirrors.

[0148] The focal length F1 of the first lens group is 20.33 mm, the focal length F2 of the second lens group is -65.81 mm, and the total focal length f of the eyepiece is 17 mm.

[0149] The eyepiece has an exit pupil distance EP of 35 mm to 45 mm and an exit pupil diameter ED of 4 mm to 8 mm;

[0150] The F number (aperture) of the eyepiece is 2.125 to 4.25;

[0151] The image height h of the eyepiece is 9.2 mm to 12.6 mm.

[0152] Table 1 shows the optical parameters of each lens in the eyepiece, which are as follows.

[0153] Table 1

[0154]

[0155] Example 2

[0156] The eyepiece provided in this embodiment 2 has the same optical structure as that of the above-mentioned embodiment 1, which can be seen in Figure 1 The differences are:

[0157] The focal length F1 of the first lens group is 22.24 mm, the focal length F2 of the second lens group is -476 mm, and the total focal length f of the eyepiece is 17 mm.

[0158] The eyepiece has an exit pupil distance EP of 35 mm to 45 mm and an exit pupil diameter ED of 4 mm to 8 mm;

[0159] The F number (aperture) of the eyepiece is 2.125 to 4.25;

[0160] The image height h of the eyepiece is 9.2 mm to 12.4 mm.

[0161] The optical parameters of each lens in the eyepiece are shown in Table 2.

[0162] Table 2

[0163]

[0164]

[0165] According to the eyepieces provided in the above-mentioned embodiment 1 and embodiment 2, the optical performance thereof is as follows: Figures 2 to 5 As shown: Figure 2 is a point diagram diagram. Figure 3 is the MTF curve graph, Figure 4 is the field curvature distortion diagram, Figure 5 This is a diagram of vertical chromatic aberration.

[0166] See also Figure 2 In the eyepieces provided in Example 1 and Example 2, the maximum value of the image point in the point array diagram is less than 30 μm.

[0167] See also Figure 3 The eyepieces provided in Examples 1 and 2 have an MTF greater than 0.2 at 14 lp / mm.

[0168] See also Figure 4For the eyepieces provided in Examples 1 and 2, the maximum distortion occurs in 1 field of view, and the absolute value is less than 14%, which is very small.

[0169] See also Figure 5 The eyepieces provided in Example 1 and Example 2 have a maximum chromatic aberration value of less than 3 μm.

[0170] According to another embodiment of the present application, an eyepiece optical system is provided, which includes the eyepiece as described above.

[0171] The above embodiments focus on 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. Considering the simplicity of the text, they will not be repeated here.

[0172] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above examples may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An eyepiece, characterized in that: The eyepiece is composed of 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; The first lens group is composed of a first lens (1), a second lens (2) and a third lens (3) which are sequentially arranged along the optical axis; The second lens group consists of a fourth lens (4), a fifth lens (5) and a sixth lens (6) arranged in sequence along the optical axis; The eyepiece satisfies: 0.049<n1 / f1+n2 / f2+n3 / f3+n4 / f4+n5 / f5+n6 / f6<0.08; wherein n1 to n6 are the refractive indices of the first lens (1) to the sixth lens (6), and f1 to f6 are the focal lengths of the first lens (1) to the sixth lens (6); The eyepiece satisfies the following: 0.65<(EP×ED) / (f×h)<2.3; wherein 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.

2. The eyepiece according to claim 1, wherein The fourth lens (4), the fifth lens (5) and the sixth lens (6) are glued together in sequence to form a glued lens group.

3. The eyepiece according to claim 2, wherein: The fourth lens (4) and the sixth lens (6) both have positive optical power, and the fifth lens (5) has negative optical power.

4. The eyepiece according to claim 3, wherein: The first lens (1), the second lens (2) and the third lens (3) all have positive optical power.

5. The eyepiece according to any one of claims 1 to 4, characterized in that The eyepiece satisfies the following: 0.042<(1 / F1)+(1 / F2)<0.08; wherein F1 is the focal length of the first lens group, and F2 is the focal length of the second lens group.

6. The eyepiece according to claim 5, wherein: The eyepiece satisfies: 1.19<F1 / f<1.3; wherein F1 is the focal length of the first lens group, and f is the total focal length of the eyepiece.

7. The eyepiece according to claim 2, wherein: The fourth lens (4) is a biconvex lens, the fifth lens (5) is a biconcave lens, and the sixth lens (6) is a concave-convex lens.

8. The eyepiece according to claim 7, wherein: The first lens (1) is a biconvex lens, the second lens (2) is a plano-convex lens, and the third lens (3) is a convex-concave lens.

9. The eyepiece according to claim 1, wherein: The exit pupil distance EP of the eyepiece is 35 mm to 45 mm, the exit pupil diameter ED of the eyepiece is 4 mm to 8 mm, and the F number of the eyepiece is 2.125 to 4.

25.

10. The eyepiece according to claim 1, wherein: The image height of the eyepiece is 9.2 mm to 12.6 mm.

11. An eyepiece optical system, characterized in that: include: The eyepiece according to any one of claims 1 to 10.

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