Eyepiece lens

Abstract

The utility model relates to an eyepiece lens, which sequentially comprises a first lens with positive focal power, a second lens with positive focal power, a third lens with negative focal power and a fourth lens with positive focal power along an optical axis from an object side to an image side, the focal length F1 of the first lens and the combined focal length F23 of the second lens and the third lens meet the following relation:-0.99 < = F1 / F23 < = 0.29. The eyepiece lens at least has one of the characteristics of large exit pupil distance, low cost, light weight, small volume, simple structure and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of lenses, in particular to an eyepiece lens. Background Art

[0002] Eyepieces are lenses used to expand the human eye's field of view and observation distance, and are key components in visual optical instruments. With the development of society and the advancement of science and technology, eyepieces are not only widely used in optical instruments such as telescopes and microscopes, but also play an important role in medical, military, aerospace, and consumer electronics fields. As the demand for eyepieces continues to increase, people's requirements for their optical performance are also becoming higher and higher.

[0003] However, the current eyepiece still has the following problems:

[0004] 1. The existing eyepiece still has a relatively small pupil distance;

[0005] 2. The existing eyepiece is heavy and cannot meet the requirements of lightweighting;

[0006] 3. Existing eyepieces have the disadvantages of being large in size and having a complex structure, and cannot meet the requirements of miniaturization.

[0007] Therefore, designing an eyepiece lens that meets at least one of the characteristics of large exit pupil distance, low cost, light weight, small size, and simple structure has become a market development trend. Utility Model Content

[0008] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an eyepiece lens having at least one of the characteristics of large exit pupil distance, low cost, light weight, small size and simple structure.

[0009] To achieve the above-mentioned purpose, the present invention provides an eyepiece lens, characterized in that, along the direction from the object side to the image side of the optical axis, it includes: a first lens with positive optical power, a second lens with positive optical power, a third lens with negative optical power, and a fourth lens with positive optical power.

[0010] The focal length F1 of the first lens and the combined focal length F23 of the second lens and the third lens satisfy the following relationship: -0.99≤F1 / F23≤0.29.

[0011] According to a technical solution of the present utility model, the object side surface of the first lens is a convex surface;

[0012] The object side surface of the second lens is convex;

[0013] The image side surface of the third lens is concave;

[0014] The object-side surface of the fourth lens is a convex surface.

[0015] According to a technical solution of the present invention, the second lens and the third lens form a cemented lens group.

[0016] According to a technical solution of the present invention, the Abbe number Vd2 of at least one lens in the cemented lens group satisfies the following relationship: 38.32≤Vd2≤70.00.

[0017] According to a technical solution of the present invention, the refractive index Nd2 of at least one lens in the cemented lens group satisfies the following relationship: 1.67≤Nd2≤2.10.

[0018] According to a technical solution of the present invention, the focal length F1 of the first lens and the total focal length F of the eyepiece lens satisfy the following relationship: 1.14≤F1 / F≤3.5.

[0019] According to a technical solution of the present invention, the combined focal length F23 of the second lens and the third lens and the total focal length F of the eyepiece lens satisfy the following relationship: -21.75≤F23 / F≤37.

[0020] According to a technical solution of the present invention, the focal length F4 of the fourth lens and the total focal length F of the eyepiece lens satisfy the following relationship: 0.35≤F4 / F≤3.3.

[0021] According to a technical solution of the present invention, the focal length F2 of the second lens and the total focal length F of the eyepiece lens satisfy the following relationship: 0.94≤F2 / F≤2.37.

[0022] According to a technical solution of the present invention, the focal length F3 of the third lens and the total focal length F of the eyepiece lens satisfy the following relationship: -2.00≤F3 / F≤-0.72.

[0023] According to a technical solution of the present invention, the distance TTL from the object side surface of the first lens to the image plane and the total focal length F of the eyepiece lens satisfy the following relationship: 1.18≤TTL / F≤2.50.

[0024] According to a technical solution of the present invention, the distance between the third lens and the fourth lens on the optical axis satisfies the following relationship: 0.10≤L34≤1.00.

[0025] According to a technical solution of the present invention, the combined focal length F23 of the second lens and the third lens and the focal length F2 of the second lens satisfy the following relationship: -0.82≤F2 / F23≤0.21.

[0026] According to a technical solution of the present invention, the focal length F1 of the first lens and the focal length F4 of the fourth lens satisfy the following relationship: 0≤F1 / F4≤3.92.

[0027] According to a technical solution of the present invention, the focal length F2 of the second lens and the focal length F3 of the third lens satisfy the following relationship: -2.50≤F2 / F3≤-0.50.

[0028] According to a technical solution of the present invention, the thickness CT2 of the second lens on the optical axis and the thickness CT3 of the third lens on the optical axis satisfy the following relationship: 2.84≤CT2 / CT3≤9.37.

[0029] According to a technical solution of the present invention, the eyepiece lens satisfies at least one of the following conditions:

[0030] 1.38≤F1 / F≤2.94,

[0031] -13.41≤F23 / F≤28.66,

[0032] 0.72≤F4 / F≤2.93,

[0033] 1.09≤F2 / F≤2.21,

[0034] -1.56≤F3 / F≤-0.80,

[0035] 1.30≤TTL / F≤2.29,

[0036] 42.75≤Vd2≤65.25,

[0037] 1.69≤Nd2≤1.89,

[0038] 0.27≤L34≤0.72,

[0039] -0.72≤F2 / F23≤0.12,

[0040] -0.86≤F1 / F23≤0.16,

[0041] 0.44≤F1 / F4≤3.4,

[0042] -2.01≤F2 / F3≤-1.11,

[0043] 3.72≤CT2 / CT3≤8.49,

[0044] Among them, F1 is the focal length of the first lens; F is the total focal length of the eyepiece lens; F23 is the combined focal length of the second lens and the third lens; F4 is the focal length of the fourth lens; F2 is the focal length of the second lens; F3 is the focal length of the third lens; TTL is the distance from the first lens to the image plane; Vd2 is the Abbe number of at least one lens in the cemented lens group consisting of the second lens and the third lens; Nd2 is the refractive index of at least one lens in the cemented lens group consisting of the second lens and the third lens; L34 is the distance between the third lens and the fourth lens on the optical axis; CT2 is the thickness of the second lens on the optical axis; CT3 is the thickness of the third lens on the optical axis.

[0045] According to the solution of the present invention, by setting the number and optical focal length of the eyepiece lenses, the ultra-wide-angle lens can achieve at least one of the following beneficial effects: a large exit pupil distance of 45mm; a glass-plastic hybrid structure to reduce cost and lens weight; a small size and a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0047] Figure 1 This is a schematic structural diagram of the eyepiece lens of Example 1 of the present utility model;

[0048] Figure 2 This is a schematic structural diagram of the eyepiece lens of Example 2 of the present utility model;

[0049] Figure 3 This is a schematic structural diagram of the eyepiece lens of Example 3 of the present utility model;

[0050] Figure 4 This is a schematic structural diagram of the eyepiece lens of Example 4 of the present utility model;

[0051] Figure 5 This is a structural diagram of the eyepiece lens of Example 5 of the present utility model. DETAILED DESCRIPTION

[0052] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0053] It should be noted that in this specification, the expressions first, second, third, etc. are only used to distinguish one feature from another, and do not represent any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the first lens.

[0054] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0055] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0056] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0057] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0058] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The following examples only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they should not be understood as limiting the scope of the patent application. It should be pointed out that for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all fall within the scope of protection of the present application.

[0059] like Figures 1 to 5 As shown, an embodiment of the present invention provides an eyepiece lens, which includes, along the optical axis from the object side to the image side, an aperture STO, a first lens L1 with positive optical focal power, a second lens L2 with positive optical focal power, a third lens L3 with negative optical focal power, a fourth lens L4 with positive optical focal power and an image plane IMA.

[0060] In the embodiment of the present invention, the object-side surface of the first lens L1 is convex and has positive refractive power, which can reduce the incident angle of light on the object-side surface of the first lens L1, thereby expanding the field of view and correcting the field curvature at different object distances.

[0061] The object-side surface of the second lens L2 is convex and has positive refractive power, which helps to reduce the incident angle of the object-side surface of the second lens L2 and expand the field of view.

[0062] The image-side surface of the third lens element L3 is concave and has negative optical power. The third lens element L3 and the second lens element L2 form a good match in optical power, which is beneficial to reducing chromatic aberration.

[0063] The object-side surface of the fourth lens L4 is convex and has positive refractive power, which is conducive to smooth transition of light and reducing the chief ray angle of the lens.

[0064] In the embodiment of the present invention, the exit pupil distance reaches 45mm. The design of long exit pupil distance is convenient for matching with other equipment and improves the comfort of human eyes. The glass-plastic hybrid structure is adopted to reduce costs while ensuring a large field of view.

[0065] In the embodiment of the present invention, the second lens L2 and the third lens L3 form a cemented lens group, forming a structure of single lens + cemented lens + single lens, which is beneficial to expanding the field of view of the lens.

[0066] In some embodiments of the present invention, the focal length F1 of the first lens element L1 and the combined focal length F23 of the second lens element L2 and the third lens element L3 satisfy the following relationship: -0.99 ≤ F1 / F23 ≤ 0.29, preferably, -0.86 ≤ F1 / F23 ≤ 0.16. By properly arranging the focal length of the first lens element L1 and the combined focal length of the second lens element L2 and the third lens element L3, the refractive power of the lenses is optimally configured, facilitating a smooth transition of light and expanding the lens's field of view.

[0067] In some embodiments of the present invention, the focal length F1 of first lens L1 and the total focal length F of the eyepiece lens satisfy the following relationship: 1.14 ≤ F1 / F ≤ 3.5, preferably, 1.38 ≤ F1 / F ≤ 2.94. Properly controlling the ratio of the focal length of first lens L1 to the total focal length of the eyepiece lens facilitates converging wide-angle incident light into the optical system, effectively expanding the optical system's field of view.

[0068] In some embodiments of the present invention, the combined focal length F23 of the second lens element L2 and the third lens element L3 satisfies the following relationship with the total focal length F of the eyepiece lens: -21.75 ≤ F23 / F ≤ 37, preferably, -13.41 ≤ F23 / F ≤ 28.66. Properly controlling the combined focal length of the second lens element L2 and the third lens element L3 is beneficial for correcting chromatic aberration.

[0069] In some embodiments of the present invention, the focal length F4 of the fourth lens element L4 and the total focal length F of the eyepiece lens satisfy the following relationship: 0.35 ≤ F4 / F ≤ 3.3, preferably 0.72 ≤ F4 / F ≤ 2.93. Properly allocating the focal length of the fourth lens element L4 facilitates smooth light transition and reduces the CRA of the lens.

[0070] In some embodiments of the present invention, the focal length F2 of the second lens L2 and the total focal length F of the eyepiece lens satisfy the following relationship: 0.94 ≤ F2 / F ≤ 2.37, preferably 1.09 ≤ F2 / F ≤ 2.21. Properly controlling the focal length of the second lens L2 facilitates smooth entry of light into the rear optical system, expanding the field of view.

[0071] In some embodiments of the present invention, the focal length F3 of the third lens element L3 and the total focal length F of the eyepiece lens satisfy the following relationship: -2.00 ≤ F3 / F ≤ -0.72, preferably, -1.56 ≤ F3 / F ≤ -0.80. By properly controlling the focal length of the third lens element L3 and properly pairing it with the second lens element L2, chromatic aberration of the system can be effectively reduced.

[0072] In some embodiments of the present invention, the distance TTL from the object side of the first lens L1 to the image plane and the total focal length F of the eyepiece lens satisfy the following relationship: 1.18 ≤ TTL / F ≤ 2.50, preferably 1.30 ≤ TTL / F ≤ 2.29. By properly controlling the total optical length of the eyepiece lens, miniaturization of the eyepiece lens is facilitated.

[0073] In some embodiments of the present invention, the Abbe number Vd2 of at least one lens in the cemented lens group satisfies the following relationship: 38.32≤Vd2≤70.00, preferably, 42.75≤Vd2≤65.25. By properly allocating the Abbe numbers of the cemented lenses, chromatic aberration of the lens can be effectively corrected.

[0074] In some embodiments of the present invention, the refractive index Nd2 of at least one lens in the cemented lens group satisfies the following relationship: 1.67≤Nd2≤2.10, preferably 1.69≤Nd2≤1.89. By properly distributing the refractive indices of the cemented lenses, system chromatic aberration can be effectively corrected.

[0075] In some embodiments of the present invention, the distance L34 between the third lens L3 and the fourth lens L4 on the optical axis satisfies the following relationship: 0.10 ≤ L34 ≤ 1.00, preferably 0.27 ≤ L34 ≤ 0.72. By properly controlling the distance between the third lens L3 and the fourth lens L4 on the optical axis, a smooth transition of light is ensured while also facilitating system miniaturization.

[0076] In some embodiments of the present invention, the combined focal length F23 of the second lens element L2 and the third lens element L3 satisfies the following relationship with the focal length F2 of the second lens element L2: -0.82≤F2 / F23≤0.21, preferably, -0.72≤F2 / F23≤0.12. This allows the second lens element L2 to have a light-collecting effect, thereby ensuring bright light transmission.

[0077] In some embodiments of the present invention, the focal length F1 of the first lens element L1 and the focal length F4 of the fourth lens element L4 satisfy the following relationship: 0 ≤ F1 / F4 ≤ 3.92, preferably, 0.44 ≤ F1 / F4 ≤ 3.4. By properly setting the focal length ratio of the first lens element L1 to the fourth lens element L4, the refractive power of the first lens element L1 and the fourth lens element L4 is optimally configured, thereby expanding the lens's field of view.

[0078] In some embodiments of the present invention, the focal length F2 of the second lens element L2 and the focal length F3 of the third lens element L3 satisfy the following relationship: -2.50 ≤ F2 / F3 ≤ -0.50, preferably, -2.01 ≤ F2 / F3 ≤ -1.11. Properly setting the focal length ratio of the second lens element L2 to the third lens element L3 helps reduce lens tolerance sensitivity and improve yield.

[0079] In some embodiments of the present invention, the thickness CT2 of the second lens element L2 and the thickness CT3 of the third lens element L3 along the optical axis satisfy the following relationship: 2.84 ≤ CT2 / CT3 ≤ 9.37, preferably, 3.72 ≤ CT2 / CT3 ≤ 8.49. Properly setting the ratio of the thicknesses of the second lens element L2 and the third lens element L3 along the optical axis improves lens manufacturability.

[0080] The following describes five specific embodiments of the optical lens according to the present invention, based on the above-described configuration. The optical lens according to the present invention comprises four lenses, with each cemented surface of the cemented lens being referred to as a surface. Together with the aperture stop STO, protective glass CG, and image plane IMA, this results in a total of 12 surfaces. The aperture stop STO is positioned before the first lens L1. For ease of description, the lens surfaces, aperture stop STO, and protective glass CG are numbered S1, S2, through S13. Furthermore, the aspheric surface satisfies the following formula:

[0081]

[0082] In the above formula, z is the axial distance from the surface to the vertex at a height y perpendicular to the optical axis along the optical axis; c represents the curvature at the vertex of the aspheric surface; k is the conic coefficient; A4, A6, A8, A 10 、A 12 、A 14 、A 16 ···represent the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, sixteenth-order···aspheric coefficients respectively.

[0083] The data of the five groups of examples are shown in Table 1 below:

[0084]

[0085]

[0086] Table 1

[0087] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not limited to the following embodiments.

[0088] Example 1

[0089] Figure 1 This is a schematic structural diagram of the eyepiece lens of Example 1 of the present utility model.

[0090] In Example 1, the first lens L1 is a convex-convex lens with positive optical power, the second lens L2 is a convex-convex lens with positive optical power, the third lens L3 is a concave-concave lens with negative optical power, and the fourth lens L4 is a convex-concave lens with positive optical power.

[0091] The second lens L2 and the third lens L3 form a cemented lens group, and the fourth lens L4 is an aspherical lens. The aperture STO is set before the first lens L1.

[0092] Table 2 lists the relevant parameters of each lens in the eyepiece lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0093] Surface serial number Surface type Curvature radius R Thickness d Refractive index Nd Abbe number Vd S1(STO) spherical surface Infinity 45.000 S2 spherical surface 33.207 6.185 1.888 40.85 S3 spherical surface -126.106 0.124 S4 spherical surface 21.221 6.632 1.863 42.85 S5 spherical surface -901.738 0.786 1.999 16.48 S6 spherical surface 18.247 0.426 S7 Aspheric 19.628 6.470 1.538 55.71 S8 Aspheric 43.913 4.756 S9 spherical surface Infinity 1.100 1.519 64.20 S10 spherical surface Infinity 1.326 S11 spherical surface Infinity 0.700 1.519 64.20 S12(IMA) spherical surface Infinity

[0094] Table 2

[0095] Table 3 lists the aspheric coefficients of the aspheric lenses of the optical lens of this embodiment, including: the quadratic surface constant K, the fourth-order aspheric coefficient A4, the sixth-order aspheric coefficient A6, the eighth-order aspheric coefficient A8, the tenth-order aspheric coefficient A 10 , 12th-order aspheric coefficient A 12 , fourteenth-order aspheric coefficient A 14 and the sixteenth-order aspheric coefficient A 16 .

[0096]

[0097]

[0098] Table 3

[0099] In the first embodiment, the image height of the eyepiece lens is 10.4 mm, and the field of view angle is 29.89°.

[0100] Combine Figure 1 As shown in Tables 1 to 3 above, the first embodiment of the present invention is an eyepiece lens having at least one of the following characteristics: a large exit pupil distance (up to 45 mm), a glass-plastic hybrid structure, low weight and cost, a small size, and a simple structure.

[0101] Example 2

[0102] Figure 2 This is a schematic structural diagram of the eyepiece lens of Example 2 of the present utility model.

[0103] In the second embodiment, the first lens L1 is a convex-convex lens with positive optical power, the second lens L2 is a convex-convex lens with positive optical power, the third lens L3 is a meniscus-concave lens with negative optical power, and the fourth lens L4 is a convex-convex lens with positive optical power.

[0104] The second lens L2 and the third lens L3 form a cemented lens group, and the fourth lens L4 is an aspherical lens. The aperture STO is set before the first lens L1.

[0105] Table 4 lists the relevant parameters of each lens in the eyepiece lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0106] Surface serial number Surface type Curvature radius R Thickness d Refractive index Nd Abbe number Vd S1(STO) spherical surface Infinity 45.000 S2 spherical surface 37.579 5.982 1.888 40.85 S3 spherical surface -283.386 0.185 S4 spherical surface 20.094 6.993 1.844 65.18 S5 spherical surface -510.949 1.793 1.999 16.48 S6 spherical surface 20.514 0.618 S7 Aspheric 11.499 6.776 1.538 55.71 S8 Aspheric -12.413 3.734 S9 spherical surface Infinity 1.100 1.519 64.20 S10 spherical surface Infinity 1.020 S11 spherical surface Infinity 0.700 1.519 64.20 S12(IMA) spherical surface Infinity

[0107] Table 4

[0108] Table 5 lists the aspheric coefficients of the aspheric lenses of the optical lens of this embodiment, including: the quadratic surface constant K, the fourth-order aspheric coefficient A4, the sixth-order aspheric coefficient A6, the eighth-order aspheric coefficient A8, the tenth-order aspheric coefficient A 10 , 12th-order aspheric coefficient A 12 , fourteenth-order aspheric coefficient A 14 and the sixteenth-order aspheric coefficient A 16 .

[0109] Surface number K <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> <![CDATA[A 12 ]]> <![CDATA[A 14 ]]> <![CDATA[A 16 <!-- 7 -->]]> S7 -10.014 1.33E-04 -2.42E-07 1.05E-09 2.82E-11 -1.42E-13 -1.72E-16 -1.19E-17 S8 -98.671 1.40E-04 -1.08E-07 -2.51E-09 -2.45E-11 -3.28E-13 -3.93E-16 1.81E-17

[0110] Table 5

[0111] In the second embodiment, the image height of the eyepiece lens is 10.4 mm, and the field angle is 32.55°.

[0112] Combine Figure 2 As shown in Tables 1, 4 and 5 above, the second embodiment of the present invention is an eyepiece lens having at least one of the following characteristics: a large exit pupil distance (up to 45 mm), a glass-plastic hybrid structure, low weight and cost, a small size, and a simple structure.

[0113] Example 3

[0114] Figure 3 This is a schematic structural diagram of the eyepiece lens of Example 3 of the present utility model.

[0115] In the third embodiment, the first lens L1 is a convex-convex lens with positive optical power, the second lens L2 is a convex-concave lens with positive optical power, the third lens L3 is a convex-concave lens with negative optical power, and the fourth lens L4 is a convex-convex lens with positive optical power.

[0116] The second lens L2 and the third lens L3 form a cemented lens group, and the fourth lens L4 is an aspherical lens. The aperture STO is set before the first lens L1.

[0117] Table 6 lists the relevant parameters of each lens in the eyepiece lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0118] Surface serial number Surface type Curvature radius R Thickness d Refractive index Nd Abbe number Vd S1(STO) spherical surface Infinity 45.000 S2 spherical surface 37.087 5.981 1.888 40.85 S3 spherical surface -211.984 0.239 S4 spherical surface 20.182 6.968 1.794 65.00 S5 spherical surface 617.639 1.845 1.999 16.48 S6 spherical surface 17.900 0.666 S7 Aspheric 12.692 6.818 1.538 55.71 S8 Aspheric -8.651 3.800 S9 spherical surface Infinity 1.100 1.519 64.20 S10 spherical surface Infinity 1.087 S11 spherical surface Infinity 0.700 1.519 64.20 S12(IMA) spherical surface Infinity 0.000

[0119] Table 6

[0120] Table 7 lists the aspheric coefficients of the aspheric lenses of the optical lens of this embodiment, including: the quadratic surface constant K, the fourth-order aspheric coefficient A4, the sixth-order aspheric coefficient A6, the eighth-order aspheric coefficient A8, the tenth-order aspheric coefficient A 10 , 12th-order aspheric coefficient A12 , fourteenth-order aspheric coefficient A 14 and the sixteenth-order aspheric coefficient A 16 .

[0121] Surface number K <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> <![CDATA[A 12 ]]> <![CDATA[A 14 ]]> <![CDATA[A 16 ]]> S7 -29.897 2.21E-04 -8.61E-07 -2.80E-10 3.81E-11 -4.42E-14 -4.39E-16 -7.09E-19 S8 -80.752 1.36E-04 -7.13E-08 -1.05E-09 -3.41E-11 -3.78E-13 -2.84E-15 -1.7E-17

[0122] Table 7

[0123] In the third embodiment, the image height of the eyepiece lens is 10.4 mm, and the field angle is 26.95°.

[0124] Combine Figure 3 As shown in Tables 1, 6 and 7 above, the third embodiment of the present invention is an eyepiece lens having at least one of the following characteristics: a large exit pupil distance (up to 45 mm), a glass-plastic hybrid structure, low weight and cost, a small size, and a simple structure.

[0125] Example 4

[0126] Figure 4 This is a schematic structural diagram of the eyepiece lens of Example 4 of the present utility model.

[0127] In Example 4, the first lens L1 is a convex-convex lens with positive optical power, the second lens L2 is a convex-concave lens with positive optical power, the third lens L3 is a convex-concave lens with negative optical power, and the fourth lens L4 is a convex-convex lens with positive optical power.

[0128] The second lens L2 and the third lens L3 form a cemented lens group, and the fourth lens L4 is an aspherical lens. The aperture STO is set before the first lens L1.

[0129] Table 8 lists the relevant parameters of each lens in the eyepiece lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0130]

[0131]

[0132] Table 8

[0133] Table 9 lists the aspheric coefficients of the aspheric lenses of the optical lens of this embodiment, including: the quadratic surface constant K, the fourth-order aspheric coefficient A4, the sixth-order aspheric coefficient A6, the eighth-order aspheric coefficient A8, the tenth-order aspheric coefficient A 10 , 12th-order aspheric coefficient A 12 , fourteenth-order aspheric coefficient A 14 and the sixteenth-order aspheric coefficient A 16 .

[0134] Surface number K <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> <![CDATA[A 12 ]]> <![CDATA[A 14 ]]> <![CDATA[A 16 ]]> S7 -8.497 2.37E-04 -8.03E-07 -2.33E-10 3.10E-11 -1.90E-13 -4.71E-16 -4.8E-18 S8 -12.511 1.01E-04 1.92E-07 -2.11E-09 -1.93E-11 -4.44E-13 -2.19E-15 3.49E-18

[0135] Table 9

[0136] In the fourth embodiment, the image height of the eyepiece lens is 10.4 mm, and the field angle is 25.6°.

[0137] Combine Figure 4 As shown in Tables 1, 8, and 9 above, the fourth embodiment of the present invention is an eyepiece lens having at least one of the following characteristics: a large exit pupil distance (up to 45 mm), a glass-plastic hybrid structure, low weight and cost, a small size, and a simple structure.

[0138] Example 5

[0139] Figure 5 This is a schematic structural diagram of the eyepiece lens of Example 5 of the present utility model.

[0140] In Example 5, the first lens L1 is a convex-concave lens with positive optical power, the second lens L2 is a convex-concave lens with positive optical power, the third lens L3 is a convex-concave lens with negative optical power, and the fourth lens L4 is a convex-convex lens with positive optical power.

[0141] The second lens L2 and the third lens L3 form a cemented lens group, and the fourth lens L4 is an aspherical lens. The aperture STO is set before the first lens L1.

[0142] Table 10 lists the relevant parameters of each lens in the eyepiece lens of this embodiment, including: surface type, curvature radius R, thickness d, refractive index Nd and Abbe number Vd of the material.

[0143]

[0144]

[0145] Table 10

[0146] Table 11 lists the aspheric coefficients of the aspheric lenses of the optical lens of this embodiment, including: the quadratic surface constant K, the fourth-order aspheric coefficient A4, the sixth-order aspheric coefficient A6, the eighth-order aspheric coefficient A8, the tenth-order aspheric coefficient A 10 , 12th-order aspheric coefficient A 12 , fourteenth-order aspheric coefficient A 14 and the sixteenth-order aspheric coefficient A 16 .

[0147] Surface number K <![CDATA[A4]]> <![CDATA[A6]]> <![CDATA[A8]]> <![CDATA[A 10 ]]> <![CDATA[A 12 ]]> <![CDATA[A 14 ]]> <![CDATA[A 16 ]]> S7 -12.335 2.56E-04 -5.88E-07 8.24E-12 2.90E-11 -2.01E-13 -7.24E-16 -6.19E-18 S8 -6.651 1.30E-04 1.67E-07 -1.92E-09 -1.50E-11 -4.38E-13 -1.24E-15 1.91E-17

[0148] Table 11

[0149] In the fifth embodiment, the image height of the eyepiece lens is 10.4 mm, and the field angle is 23.37°.

[0150] Combine Figure 5 As shown in Tables 1, 10, and 11 above, the fifth embodiment is an eyepiece lens having at least one of the following characteristics: a large exit pupil distance (up to 45 mm), a glass-plastic hybrid structure, low weight and cost, a small size, and a simple structure.

[0151] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the utility model disclosed herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the concept of the utility model. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An eyepiece lens, characterized in that: Along the optical axis from the object side to the image side, it includes: a first lens (L1) with positive focal power, a second lens (L2) with positive focal power, a third lens (L3) with negative focal power, and a fourth lens (L4) with positive focal power. The focal length F1 of the first lens (L1) and the combined focal length F23 of the second lens (L2) and the third lens (L3) satisfy the following relationship: -0.99≤F1 / F23≤0.

29.

2. The eyepiece lens according to claim 1, wherein: The object side surface of the first lens (L1) is a convex surface; The object-side surface of the second lens (L2) is a convex surface; The image side surface of the third lens (L3) is concave; The object-side surface of the fourth lens (L4) is convex.

3. The eyepiece lens according to claim 1, wherein: The second lens (L2) and the third lens (L3) form a cemented lens group.

4. The eyepiece lens according to claim 3, wherein: The Abbe number Vd2 of at least one lens in the cemented lens group satisfies the following relationship: 38.32≤Vd2≤70.

00.

5. The eyepiece lens according to claim 3, wherein: The refractive index Nd2 of at least one lens in the cemented lens group satisfies the following relationship: 1.67≤Nd2≤2.

10.

6. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The focal length F1 of the first lens (L1) and the total focal length F of the eyepiece lens satisfy the following relationship: 1.14≤F1 / F≤3.

5.

7. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The combined focal length F23 of the second lens (L2) and the third lens (L3) and the total focal length F of the eyepiece lens satisfy the following relationship: -21.75≤F23 / F≤37.

8. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The focal length F4 of the fourth lens (L4) and the total focal length F of the eyepiece lens satisfy the following relationship: 0.35≤F4 / F≤3.

3.

9. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The focal length F2 of the second lens (L2) and the total focal length F of the eyepiece lens satisfy the following relationship: 0.94≤F2 / F≤2.

37.

10. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The focal length F3 of the third lens (L3) and the total focal length F of the eyepiece lens satisfy the following relationship: -2.00≤F3 / F≤-0.

72.

11. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The distance TTL from the object side surface of the first lens (L1) to the image plane and the total focal length F of the eyepiece lens satisfy the following relationship: 1.18≤TTL / F≤2.

50.

12. The eyepiece lens according to any one of claims 1 to 5, characterized in that: A distance L34 between the third lens (L3) and the fourth lens (L4) on the optical axis satisfies the following relationship: 0.10≤L34≤1.

00.

13. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The combined focal length F23 of the second lens (L2) and the third lens (L3) and the focal length F2 of the second lens (L2) satisfy the following relationship: -0.82≤F2 / F23≤0.

21.

14. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The focal length F1 of the first lens (L1) and the focal length F4 of the fourth lens (L4) satisfy the following relationship: 0≤F1 / F4≤3.

92.

15. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The focal length F2 of the second lens (L2) and the focal length F3 of the third lens (L3) satisfy the following relationship: -2.50≤F2 / F3≤-0.

50.

16. The eyepiece lens according to any one of claims 1 to 5, characterized in that: The thickness CT2 of the second lens (L2) on the optical axis and the thickness CT3 of the third lens (L3) on the optical axis satisfy the following relationship: 2.84≤CT2 / CT3≤9.

37.

17. The eyepiece lens according to claim 1, wherein: The eyepiece lens meets at least one of the following conditions: 1.38≤F1 / F≤2.94, -13.41≤F23 / F≤28.66, 0.72≤F4 / F≤2.93, 1.09≤F2 / F≤2.21, -1.56≤F3 / F≤-0.80, 1.30≤TTL / F≤2.29, 42.75≤Vd2≤65.25, 1.69≤Nd2≤1.89, 0.27≤L34≤0.72， -0.72≤F2 / F23≤0.12, -0.86≤F1 / F23≤0.16, 0.44≤F1 / F4≤3.4, -2.01≤F2 / F3≤-1.11, 3.72≤CT2 / CT3≤8.49, Wherein, F1 is the focal length of the first lens (L1); F is the total focal length of the eyepiece lens; F23 is the combined focal length of the second lens (L2) and the third lens (L3); F4 is the focal length of the fourth lens (L4); F2 is the focal length of the second lens (L2); F3 is the focal length of the third lens (L3); TTL is the distance from the first lens (L1) to the image plane; Vd(B1) is the Abbe number of at least one lens in the cemented lens group consisting of the second lens (L2) and the third lens (L3); Nd(B1) is the refractive index of at least one lens in the cemented lens group consisting of the second lens (L2) and the third lens (L3); L34 is the distance between the third lens (L3) and the fourth lens (L4) on the optical axis; CT2 is the thickness of the second lens (L2) on the optical axis; CT3 is the thickness of the third lens (L3) on the optical axis.

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