Long-eye-distance eyepiece and optical system

Abstract

The utility model provides a long-lens-eye-distance eyepiece and an optical system, and the long-lens-eye-distance eyepiece comprises a plurality of lenses which are a first lens, a second lens, a third lens, a fourth lens and a fifth lens from the object side to the image side along an optical axis in sequence. The first lens has positive diopter, the object side surface is a convex surface, and the image side surface is a concave surface; the second lens has positive diopter, the object side surface is a convex surface, and the image side surface is a convex surface; the third lens has negative diopter, the object side surface is a concave surface, and the image side surface is a concave surface; the fourth lens has positive diopter, the object side surface is a convex surface, and the image side surface is a plane; the fifth lens has negative diopter, and the object side surface of the fifth lens is a concave surface; the image side surface is a plane. The long-lens-eye-distance eyepiece has the advantages that the long-lens-eye-distance eyepiece is long, the use comfort is effectively improved, the exit pupil diameter is large, and the problem of pupil drift can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to an eyepiece with a long lens-eye distance and an optical system. Background Art

[0002] 1. Conventional eyepieces are limited by the size of the exit pupil distance. The shorter the distance, the shorter the eyepiece distance, which can easily cause visual fatigue during observation.

[0003] 2. When the exit pupil diameter of the eyepiece is small, the observation position of the human eye must be consistent with the optical axis of the eyepiece. Once it is inconsistent, pupil drift will occur; when the exit pupil diameter is larger, the corresponding light transmission becomes larger, and the observed image contrast will also decrease significantly.

[0004] 3. Since the eyepiece is used directly by the human eye, it generally has higher requirements on distortion. Therefore, for eyepieces with relatively large magnification, distortion correction is a big difficulty.

[0005] 4. Conventional eyepieces are usually designed according to the vision of normal human eyes. However, for people with myopia or hyperopia, there will be deviations in the position of the image due to different refractive powers. When the eyepiece is in a fixed position, the image clarity observed by different people will be significantly different. Utility Model Content

[0006] The utility model aims to solve the above problems and provide an eyepiece with a long lens-eye distance.

[0007] The technical solution of the present disclosure is achieved as follows:

[0008] In a first aspect, the present disclosure provides a long-eye distance eyepiece, comprising a plurality of lenses, wherein the plurality of lenses are, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a fourth lens and a fifth lens;

[0009] The refractive index of the first lens is 1.8, the refractive index of the second lens is 1.6, the refractive index of the third lens is 1.8, the refractive index of the fourth lens is 1.8, and the refractive index of the fifth lens is 1.6-1.8.

[0010] The first lens has positive refractive power, the object side surface is convex, and the image side surface is concave;

[0011] The second lens has positive refractive power, the object side surface is convex, and the image side surface is convex;

[0012] The third lens has negative refractive power, the object side surface is concave, and the image side surface is concave;

[0013] The fourth lens has positive refractive power, the object side surface is convex, and the image side surface is flat;

[0014] The fifth lens element has negative refractive power, and its object side surface is concave; and its image side surface is flat.

[0015] In one embodiment, the second lens and the third lens are combined into a cemented lens, wherein the second lens is a positive lens and the third lens is a negative lens.

[0016] In one embodiment, the optical system of the eyepiece satisfies the following relationship: 正 --V| 负 |>40;

[0017] Among them, Vd 正 is the Abbe number of the second lens, Vd 正 is the Abbe number of the third lens.

[0018] In one embodiment, the optical system of the eyepiece satisfies the following relationship: 1.8<n1<1.9, 40<|Vd1|<50;

[0019] Wherein, n1 is the refractive index of the first lens, and Vd1 is the Abbe number of the first lens.

[0020] In one embodiment, the refractive index temperature coefficient of the second lens is defined as dn2 / Dt,t, and satisfies the following relationship: dn2 / Dt<0.

[0021] In one embodiment, the optical system of the eyepiece satisfies the following relationship: f5<0; f5 is the focal length of the fifth lens

[0022] The advantages or beneficial effects of the above technical solution include at least:

[0023] 1. Under the premise that the illumination is not too small, increase the pupil distance to improve the user's comfort when observing.

[0024] 2. Set an appropriate exit pupil diameter to avoid pupil drift as much as possible while ensuring that the imaging resolution is not less than the resolution of the human eye.

[0025] 3. Optimize the system structure to ensure that the absolute value of distortion is no more than 2%.

[0026] 4. Add a certain range of diopter adjustment mechanism to ensure that users with different vision can use it normally and increase the practicality of the lens.

[0027] In a second aspect, the present disclosure provides an optical system comprising an eyepiece with a long lens-eye distance as described in any one of the above items.

[0028] The beneficial effects of this optical system have been clearly explained in the above-mentioned long-eye distance eyepiece, so they will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings illustrate exemplary implementations of the present disclosure of embodiments of the utility model and, together with the description, are used to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure, and the accompanying drawings are included in and constitute a part of this specification.

[0030] Figure 1 The MTF diagram of the first embodiment of the utility model is shown;

[0031] Figure 2 The distortion curve of the first embodiment of the utility model is shown;

[0032] Figure 3 The relative illumination diagram of the first embodiment of the utility model is shown;

[0033] Figure 4 The lens arrangement diagram of the first embodiment of the utility model is shown (from left to right, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the protective lens);

[0034] Figure 5 The MTF diagram of the second embodiment of the utility model is shown;

[0035] Figure 6 The distortion curve of the second embodiment of the utility model is shown;

[0036] Figure 7 The relative illumination diagram of the second embodiment of the present utility model is shown;

[0037] Figure 8 The lens arrangement diagram of the second embodiment of the present utility model is shown (from left to right are the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the protective lens). DETAILED DESCRIPTION

[0038] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0039] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] It should be understood that the term "including" and its variations used in this document are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". Relevant definitions of other terms will be given in the description below. It should be noted that the concepts of "first", "second", etc. mentioned in this disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0041] It should be noted that the modifications of "one" and "plurality" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0042] The names of the messages or information exchanged between multiple devices in the embodiments of the present disclosure are only used for illustrative purposes and are not used to limit the scope of these messages or information.

[0043] A long-eye distance eyepiece includes a plurality of lenses, which are sequentially arranged along the optical axis from the object side to the image side as a first lens, a second lens, a third lens, a fourth lens and a fifth lens. The lens adopts a total of five spherical lenses. By reasonably allocating the optical focal length of each lens, an eyepiece with a magnification of 6 times is realized, and the maximum imaging target surface size can reach 13 mm.

[0044] The first lens has positive refractive power, with a convex object side and a concave image side;

[0045] The second lens has positive refractive power, with a convex object-side surface and a convex image-side surface;

[0046] The third lens has negative refractive power, with a concave object-side surface and a concave image-side surface;

[0047] The fourth lens has positive refractive power, the object side surface is convex, and the image side surface is flat;

[0048] The fifth lens has negative refractive power, the object side surface is concave, and the image side surface is flat;

[0049] Among them, the refractive index of the first lens is: 1.8, the refractive index of the second lens is: 1.6, the refractive index of the third lens is: 1.8, the refractive index of the fourth lens is: 1.8, and the refractive index of the fifth lens is: 1.6~1.8.

[0050] The second lens and the third lens are combined into a cemented lens, wherein the second lens is a positive lens, the third lens is a negative lens, and the optical system satisfies the relationship |Vdpositive-Vd||>40, wherein Vdpositive is the Abbe number of the second lens, and Vdneg is the Abbe number of the third lens, and the cemented lens group can effectively correct chromatic aberration;

[0051] Based on the above, the exit pupil diameter of the lens is 18mm, the maximum lens-to-eye distance can reach 35mm, and the imaging resolution is far superior to that of the human eye.

[0052] Based on the above, the diopter adjustment range of the optical system of the lens is -4dpt to +4dpt, and the optical system is equipped with an adjustment ring that can be used to adjust the lens-object distance.

[0053] Furthermore, the optical distortion of the optical system of the lens is less than 0.5%, the relative illumination is greater than 60%, the system dimensions are φ57mm*49mm, and the total optical length is less than 43mm

[0054] Specifically, the optical system of the eyepiece satisfies the following relationship: 1.8<n1<1.9, 40<|Vd1|<50; wherein n1 is the refractive index of the first lens, and Vd1 is the Abbe number of the first lens, which can make the lens have a higher refractive index, which is not only beneficial for correcting off-axis aberrations, but also beneficial for reducing the lens aperture.

[0055] The refractive index temperature coefficient of the second lens is defined as dn2 / Dt and satisfies the following relationship: dn2 / Dt<0; this is conducive to the optical athermal design of the system and ensures clear imaging of the lens at an ambient temperature of +80℃ to -40℃.

[0056] The optical system of the eyepiece satisfies the following relationship: f5<0; f5 is the focal length of the fifth lens, which serves to increase the eyepiece distance.

[0057] The refractive index of the first lens is 1.8, the refractive index of the second lens is 1.6, the refractive index of the third lens is 1.8, the refractive index of the fourth lens is 1.8, and the refractive index of the fifth lens is 1.6-1.8. Preferably, the refractive index of the fifth lens is 1.5.

[0058] In the first embodiment, the parameters of the first to fifth lenses are shown in Table 1:

[0059] Table 1:

[0060]

[0061] Among them, the focal length parameters of the first to fifth lenses are shown in Table 2:

[0062] Table 2:

[0063] LENS focal length (1-2)P1 37 (3-4)P2 23 (4-5)P3 -11.4 (6-7)P4 25 (8-9)P5 -43.6 (10-11)P6 Infinity

[0064] In the second embodiment, the parameters of the first to fifth lenses are shown in Table 3:

[0065] Table 3:

[0066]

[0067] Among them, the focal length parameters of the first to fifth lenses are shown in Table 4:

[0068] Table 4:

[0069] LENS focal length (1-2)P1 28 (3-4)P2 26.8 (4-5)P3 -10.2 (6-7)P4 24.5 (8-9)P5 -39.7 (10-11)P6 Infinity

[0070] The comparison of optical system parameters of the first embodiment and the second embodiment is shown in Table 5:

[0071] Table 5: Wherein, f is the focal length of the optical system; BFL is the optical back focus of the optical system; y is the image height (the total image height of the image on the sensor); the unit of TTL optical total length (the distance from the first surface of the first lens to the image plane) is: mm.

[0072] The present application also provides an optical system, comprising the long-eye-distance eyepiece as described in any of the above items; the beneficial effects of this optical system have been clearly explained in the above-mentioned long-eye-distance eyepiece, and will not be repeated here.

[0073] In the description of the present disclosure, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure.

[0074] Those skilled in the art should understand that the above embodiments are only for the purpose of clearly illustrating the present disclosure, and are not intended to limit the scope of the present disclosure. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present disclosure.

Claims

1. A long-eye distance eyepiece, characterized in that: it comprises a plurality of lenses, wherein the plurality of lenses are, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a fourth lens and a fifth lens; Among them, the refractive index of the first lens is: 1.8, the refractive index of the second lens is: 1.6, the refractive index of the third lens is: 1.8, and the refractive index of the fourth lens is: 1.8, the refractive index of the fifth lens is: 1.6-1.8; The first lens has positive refractive power, the object side surface is convex, and the image side surface is concave; The second lens has positive refractive power, the object side surface is convex, and the image side surface is convex; The third lens has negative refractive power, the object side surface is concave, and the image side surface is concave; The fourth lens has positive refractive power, the object side surface is convex, and the image side surface is flat; The fifth lens element has negative refractive power, and its object side surface is concave; and its image side surface is flat.

2. The long-eye distance eyepiece according to claim 1, characterized in that: The second lens and the third lens are combined into a cemented lens, wherein the second lens is a positive lens and the third lens is a negative lens.

3. The long-eye distance eyepiece according to claim 2, characterized in that: The optical system of the eyepiece satisfies the following relationship: |Vd 正 -Vd||>40; Among them, Vd 正 is the Abbe number of the second lens, Vd 正 is the Abbe number of the third lens.

4. The long-eye distance eyepiece according to claim 1, characterized in that: The optical system of the eyepiece satisfies the following relationship: 1.8<n1<1.9, 40<|Vd1|<50; Wherein, n1 is the refractive index of the first lens, and Vd1 is the Abbe number of the first lens.

5. The long-eye distance eyepiece according to claim 1, characterized in that: The refractive index temperature coefficient of the second lens is defined as dn2 / Dt, and satisfies the following relationship: dn2 / Dt<0.

6. The long-eye distance eyepiece according to claim 1, characterized in that: The optical system of the eyepiece satisfies the following relationship: f5<0; f5 is the focal length of the fifth lens.

7. An optical system, characterized in that: Including an eyepiece with a long lens eye distance as described in any one of claims 1-6.

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