Large exit pupil distance eyepiece lens

Abstract

The embodiment of the utility model discloses an eyepiece lens with a large exit pupil distance. The eyepiece lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from an observation side to a display side along an optical axis, the first lens is a glass spherical lens with positive focal power, the second lens is a glass spherical lens with positive focal power, the third lens is a glass spherical lens with negative focal power, the fourth lens is a glass spherical lens with negative focal power, and the fifth lens is a glass spherical lens with positive focal power; the opposite surfaces of the second lens and the third lens are glued to form a first glued lens group. According to the embodiment of the utility model, an all-glass 5G structure is finally designed and adopted, and through matching of lens materials and reasonable distribution of focal power, the eyepiece lens with long exit pupil distance, long back intercept, small aberration and low cost is realized, the exit pupil distance reaches 48mm, and the back intercept is greater than 12mm.

Description

Technical Field

[0001] This utility model relates to the field of optical lens technology, and in particular to a large exit pupil eyepiece lens. Background Technology

[0002] The primary function of an eyepiece is to further magnify the image obtained from the objective lens, thus facilitating observation by the human eye. The eyepiece's construction is relatively simple, typically consisting of two parts: the upper lens, called the eyepiece lens, which magnifies the image; and the lower lens, called the converging lens or field lens, which ensures uniform image brightness. The eyepiece has a small aperture angle, resulting in lower resolution, but it is sufficient for magnifying the objective lens. Common eyepiece magnifications include 8×, 10×, 12.5×, and 16×. In general, the eyepiece, as an important component of instruments such as telescopes and microscopes, further magnifies the observed object, affecting the quality and clarity of the final image. In increasingly diverse applications, eyepiece lenses also need to have long external pupil distances and long backcuts to allow sufficient safe viewing distances and accommodate replacement and reassembly requirements.

[0003] Current eyepieces generally suffer from various problems such as small exit pupil distance (usually less than 22mm), large distortion, and severe chromatic aberration. Therefore, the development of eyepieces with longer exit pupil distance, smaller distortion, and better image quality is particularly important. Utility Model Content

[0004] This invention provides an eyepiece lens with a large exit pupil distance, thereby achieving an eyepiece lens with a long exit pupil distance, a long back focal length, and low distortion.

[0005] This utility model embodiment provides a large exit pupil distance eyepiece lens, including a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged sequentially along the optical axis from the observation side to the display side;

[0006] The first lens is a glass spherical lens with positive optical power, the second lens is a glass spherical lens with positive optical power, the third lens is a glass spherical lens with negative optical power, the fourth lens is a glass spherical lens with negative optical power, and the fifth lens is a glass spherical lens with positive optical power.

[0007] The opposing surfaces of the second lens and the third lens are glued together to form a first cemented lens group.

[0008] Optionally, the opposing surfaces of the fourth lens and the fifth lens are cemented together to form a second cemented lens group.

[0009] Optionally, the eyepiece lens satisfies the following condition: 0.41≤Φ1 / Φ≤0.7;

[0010] Wherein, Φ1 is the optical power of the first lens, and Φ is the optical power of the eyepiece lens.

[0011] Optionally, the eyepiece lens satisfies the following condition: 1.91 ≤ EL / TH ≤ 3.09;

[0012] Wherein, EL is the exit pupil distance of the eyepiece lens, and TH is the on-axis distance from the observation side surface of the first lens to the display side surface of the third lens.

[0013] Optionally, the second lens and the third lens satisfy the following condition: |vd2-vd3|≥26.2;

[0014] Wherein, vd2 is the Abbe number of the second lens, and vd3 is the Abbe number of the third lens.

[0015] Optionally, the eyepiece lens satisfies the following condition: -1.52≤Φ3 / Φ≤-0.87;

[0016] Wherein, Φ3 is the optical power of the third lens, and Φ is the optical power of the eyepiece lens.

[0017] Optionally, the eyepiece lens satisfies the following condition: -0.25≤Φ4 / Φ≤-0.02;

[0018] Wherein, Φ4 is the optical power of the fourth lens, and Φ is the optical power of the eyepiece lens.

[0019] Optionally, the eyepiece lens satisfies the following condition: 0.61≤(|SAG21|+|SAG22|) / TH2≤0.97;

[0020] Wherein, SAG21 is the sag at the maximum effective radius of the observation side surface of the second lens, SAG22 is the sag at the maximum effective radius of the display side surface of the second lens, and TH2 is the center thickness of the second lens.

[0021] Optionally, the eyepiece lens satisfies the following condition: 0.32≤(Φ4 / vd4+Φ5 / vd5)*1000≤0.74;

[0022] Wherein, Φ4 is the optical power of the fourth lens, vd4 is the Abbe number of the fourth lens, Φ5 is the optical power of the fifth lens, and vd5 is the Abbe number of the fifth lens.

[0023] In this embodiment of the invention, the first, second, and fifth lenses are configured to have positive optical power, while the third and fourth lenses are configured to have negative optical power. Essentially, this positive-positive-negative-negative-positive optical power distribution allows light to pass through the optical system more smoothly, balancing the distribution of aberrations and thus achieving better overall aberration correction, reducing distortion, and ensuring sufficiently clear image quality. Simultaneously, configuring the second and third lenses as a cemented lens group can, on the one hand, appropriately correct chromatic aberration and improve field curvature and coma, thereby further optimizing image quality; on the other hand, it can reduce the spacing between lenses, shrink the overall size of the lens, and increase the exit pupil distance of the eyepiece. Furthermore, using glass spherical lenses for all five lenses utilizes the properties of glass to reduce the sensitivity of the optical system's imaging process to temperature, minimizing lens deformation at different temperatures and ensuring clear imaging even in high and low temperature environments. Therefore, the present invention can ultimately achieve an eyepiece lens with a long exit pupil distance, a long back focal length, small aberrations, and low cost by designing an all-glass 5G structure and by matching lens materials and rationally allocating optical power. The exit pupil distance reaches 48mm and the back focal length is greater than 12mm. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a large exit pupil distance eyepiece lens provided in Embodiment 1 of this utility model;

[0025] Figure 2 This is a schematic diagram of the structure of a large exit pupil distance eyepiece lens provided in Embodiment 2 of this utility model;

[0026] Figure 3 for Figure 1 The dot diagram of the eyepiece lens is shown;

[0027] Figure 4 for Figure 1 The field curvature distortion curve of the eyepiece lens is shown.

[0028] Figure 5 for Figure 2 The dot diagram of the eyepiece lens is shown;

[0029] Figure 6 for Figure 2 The field curvature distortion curve of the eyepiece lens is shown.

[0030] Figure 7 This is a schematic diagram of the structure of a large exit pupil distance eyepiece lens provided in Embodiment 3 of this utility model;

[0031] Figure 8 for Figure 7 The dot diagram of the eyepiece lens is shown;

[0032] Figure 9 for Figure 7The field curvature distortion curve of the eyepiece lens is shown. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0034] Figure 1 This is a schematic diagram of the structure of a large exit pupil eyepiece lens provided in Embodiment 1 of this utility model, for reference. Figure 1 The eyepiece lens includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, and a fifth lens 50 arranged sequentially along the optical axis from the observation side to the display side; the first lens 10 is a glass spherical lens with positive optical power, the second lens 20 is a glass spherical lens with positive optical power, the third lens 30 is a glass spherical lens with negative optical power, the fourth lens 40 is a glass spherical lens with negative optical power, and the fifth lens 50 is a glass spherical lens with positive optical power; the opposing surfaces of the second lens 20 and the third lens 30 are cemented together to form a first cemented lens group.

[0035] First, for optical lenses, optical power equals the difference between the image-side beam convergence and the object-side beam convergence; it characterizes the optical system's ability to deflect light. The larger the absolute value of optical power, the stronger the bending ability of light; the smaller the absolute value, the weaker the bending ability. When optical power is positive, the refraction of light is converging; when optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).

[0036] In the eyepiece lens provided in this embodiment, each lens can be fixed in a lens barrel. Figure 1 (not shown in the image) such as Figure 1As shown, in this embodiment of the invention, the first lens 10, the second lens 20, and the fifth lens 50 are configured to have positive optical power, while the third lens 30 and the fourth lens 40 are configured to have negative optical power. Essentially, this positive-positive-negative-negative-positive optical power distribution allows light to pass through the optical system more smoothly, balancing the distribution of aberrations and thus achieving better overall aberration correction, reducing distortion, and ensuring sufficiently clear image quality. Simultaneously, configuring the second lens 20 and the third lens 30 as a cemented lens group can, on the one hand, appropriately correct chromatic aberration and improve field curvature and coma, thereby further optimizing image quality; on the other hand, it can reduce the spacing between the lenses, shrink the overall size of the lens, and increase the exit pupil distance of the eyepiece.

[0037] Furthermore, in this embodiment of the invention, all five lenses are made of glass spherical lenses. This utilizes the properties of glass to reduce the temperature sensitivity of the optical system's imaging process, minimize lens deformation at different temperatures, and ensure clear imaging even in high and low temperature environments. Therefore, this embodiment of the invention, through the design of an all-glass 5G structure and the appropriate combination and allocation of lens materials and optical power, achieves an eyepiece lens with a long exit pupil distance, a long back focal length, low aberration, and low cost, achieving an exit pupil distance of 48mm and a back focal length greater than 12mm.

[0038] Figure 2 This is a schematic diagram of the structure of a large exit pupil eyepiece lens provided in Embodiment 2 of this utility model, for reference. Figure 2 Optionally, the opposing surfaces of the fourth lens 40 and the fifth lens 50 are cemented together to form a second cemented lens group.

[0039] Similarly, by cementing the fourth lens 40 and the fifth lens 50 together to form a cemented lens group, the distance between the lenses can be reduced while correcting aberrations, thereby further reducing the overall size of the lens and further increasing the exit pupil distance of the eyepiece.

[0040] Optionally, the eyepiece lens satisfies the following condition: 0.41≤Φ1 / Φ≤0.7; where Φ1 is the optical power of the first lens 10 and Φ is the optical power of the eyepiece lens.

[0041] Specifically, by controlling the optical power of the first lens, the angle and direction of light rays can be effectively focused, preventing excessive divergence in the angle of light entering the lens, thereby reducing off-axis aberrations and improving the image quality of the eyepiece lens. Furthermore, controlling the optical power of the first lens 10 within the aforementioned range facilitates the distribution of the overall optical power of the system, rationally balancing the aberrations generated by each lens, and achieving a lower overall aberration level for the optical system.

[0042] Optionally, the eyepiece lens satisfies the following condition: 1.91≤EL / TH≤3.09; where EL is the exit pupil distance of the eyepiece lens, and TH is the on-axis distance from the observation side surface of the first lens 10 to the display side surface of the third lens 30.

[0043] Specifically, the exit pupil distance refers to the axial distance from the aperture stop STO to the object-side surface of the first lens 10. By limiting the space range of the front lens element to meet the above requirements, the lens structure can be made more compact, ensuring a longer exit pupil distance while constraining the overall length of the lens.

[0044] Optionally, the second lens 20 and the third lens 30 satisfy the following condition: |vd2-vd3|≥26.2; where vd2 is the Abbe number of the second lens 20 and vd3 is the Abbe number of the third lens 30.

[0045] Specifically, by constraining the dispersion capabilities of the second lens 20 and the third lens 30, the chromatic aberration of light entering the front lens of the eyepiece can be controlled, keeping the chromatic aberration within a certain range, which helps to reduce the overall chromatic aberration of the system.

[0046] Optionally, the eyepiece lens satisfies the following condition: -1.52≤Φ3 / Φ≤-0.87; where Φ3 is the optical power of the third lens 30, and Φ is the optical power of the eyepiece lens.

[0047] Specifically, by controlling the third lens and the system as a whole to be within a similar range of absolute optical power, it is beneficial to the smooth transition of light from the front to the back of the lens, resulting in better tolerances for individual lenses and assembly. Under the above conditions, it is also beneficial to cancel out the aberrations at the front and back of the system, reduce the overall aberrations of the optical system, and help improve the image quality of the system.

[0048] Optionally, the eyepiece lens satisfies the following condition: -0.25≤Φ4 / Φ≤-0.02; where Φ4 is the optical power of the fourth lens 40, and Φ is the optical power of the eyepiece lens.

[0049] Specifically, the fourth lens 40 is meniscus-shaped, which can be used to correct the field curvature of the system. At the same time, controlling the optical power of the fourth lens 40 to be relatively small is beneficial to the balanced distribution of optical power of the remaining lenses, thereby improving the tolerance sensitivity of the optical system.

[0050] Optionally, the eyepiece lens satisfies the following condition: 0.61≤(|SAG21|+|SAG22|) / TH2≤0.97; where SAG21 is the sag at the maximum effective radius of the observation side surface of the second lens 20, SAG22 is the sag at the maximum effective radius of the display side surface of the second lens 20, and TH2 is the center thickness of the second lens 20.

[0051] Specifically, by controlling the sagitta and thickness of the second lens 20, it is possible to avoid the second lens 20 being too thin or too thick, which can reduce the difficulty of aberration correction and is beneficial to improving the image quality of the eyepiece lens.

[0052] Optionally, the eyepiece lens satisfies the following condition: 0.32≤(Φ4 / vd4+Φ5 / vd5)*1000≤0.74; where Φ4 is the optical power of the fourth lens 40, vd4 is the Abbe number of the fourth lens 40, Φ5 is the optical power of the fifth lens 50, and vd5 is the Abbe number of the fifth lens 50.

[0053] Specifically, by constraining the chromatic aberration capability of the rear lens element, the chromatic aberration generated by other lenses in the system can be effectively offset, ensuring that the overall chromatic aberration of the system is within a small range.

[0054] Continue to refer to Figure 1 and Figure 2 In this embodiment of the invention, the eyepiece lens may also be provided with a flat glass plate 60; the flat glass plate 60 is located on the side of the fifth lens 50 away from the fourth lens 40. The flat glass plate 60 can be protective glass or a filter with a filtering function.

[0055] Based on the same concept, this utility model provides three different specific embodiments, and their optical power relationship and related physical optical parameter design ranges are shown in Table 1:

[0056] Table 1 shows the relationship between the optical power of each lens and the design values ​​of related physical and optical parameters in the three embodiments.

[0057] Scope of protection Example 1 Example 2 Example 3 lower limit upper limit Φ1 / Φ 0.6667 0.4792 0.4511 0.41 0.7 EL / TH 2.5144 1.9876 1.9917 1.91 3.09 |vd2-vd3| 44.8 38.3 28.3 26.2 Φ3 / Φ -0.9304 -1.1888 -1.2353 -1.52 -0.87 Φ4 / Φ -0.1133 -0.2401 -0.1095 -0.25 -0.02 (|SAG21|+|SAG22|) / TH2 0.9455 0.6624 0.6431 0.61 0.97 (Φ4 / vd4+Φ5 / vd5)*1000 0.3848 0.7179 0.6230 0.32 0.74

[0058] like Figure 1 The parameter design values ​​of each lens in the eyepiece lens of Embodiment 1 are shown in Table 2:

[0059] Table 2 shows a design value for each lens in the eyepiece lens of Example 1.

[0060]

[0061]

[0062] The surface numbers in Table 2 are assigned according to the surface sequence of each lens; “Object” represents the object plane of the eyepiece lens; “STO” represents the aperture stop of the eyepiece lens; “IMAGE” represents the image plane of the eyepiece lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; the thickness represents the central axial distance between the current surface and the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light; a blank space indicates that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface.

[0063] Figure 3 for Figure 1 The diagram shown is a dot plot of the eyepiece lens. A dot plot refers to the diffuse pattern formed by the aberrations of light rays emitted from a single light source. These rays, after passing through the optical system, no longer converge at a single point on the image plane, but instead form a scattered pattern over a certain area. The distribution of points in the dot plot can approximately represent the degree of concentration of the light rays and reflect the imaging quality of the system. For example... Figure 3 As shown, the diffusion patterns of light rays (0.436μm~0.656μm) are relatively concentrated in each field of view, indicating that the eyepiece lens has low chromatic aberration and aberration across the entire field of view, enabling high-resolution imaging.

[0064] Figure 4 for Figure 1 The diagram shows the field curvature distortion curve of the eyepiece lens. In the coordinate system on the left side of the diagram, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents the meridion and S represents the sagitta; from Figure 4 It can be seen that the eyepiece lens provided in this embodiment effectively controls the field curvature, that is, during imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of distortion, in percentage; the vertical axis represents the normalized image height, which has no unit; from Figure 4 As can be seen, the distortion of the lens provided in this embodiment has been well corrected, and the imaging distortion is small.

[0065] like Figure 2 The parameter design values ​​of each lens in the eyepiece lens of Embodiment 2 are shown in Table 3:

[0066] Table 3 shows a design value for each lens in the eyepiece lens of Example 2.

[0067]

[0068]

[0069] The surface numbers in Table 3 are assigned according to the surface sequence of each lens; “Object” represents the object plane of the eyepiece lens; “STO” represents the aperture stop of the eyepiece lens; “IMAGE” represents the image plane of the eyepiece lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; the thickness represents the central axial distance between the current surface and the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light; a blank space indicates that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface.

[0070] Figure 5 for Figure 2 The diagram shown is a dot plot of the eyepiece lens. A dot plot refers to the diffuse pattern formed by the aberrations of light rays emitted from a single light source. These rays, after passing through the optical system, no longer converge at a single point on the image plane, but instead form a scattered pattern over a certain area. The distribution of points in the dot plot can approximately represent the degree of concentration of the light rays and reflect the imaging quality of the system. For example... Figure 5 As shown, the diffusion patterns of light rays (0.436μm~0.656μm) are relatively concentrated in each field of view, indicating that the eyepiece lens has low chromatic aberration and aberration across the entire field of view, enabling high-resolution imaging.

[0071] Figure 6 for Figure 2 The diagram shows the field curvature distortion curve of the eyepiece lens. In the coordinate system on the left side of the diagram, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents the meridion and S represents the sagitta; from Figure 6 It can be seen that the eyepiece lens provided in this embodiment effectively controls the field curvature, that is, during imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of distortion, in percentage; the vertical axis represents the normalized image height, which has no unit; from Figure 6 As can be seen, the distortion of the lens provided in this embodiment has been well corrected, and the imaging distortion is small.

[0072] Figure 7 This is a schematic diagram of the structure of a large exit pupil eyepiece lens provided in Embodiment 3 of this utility model, for reference. Figure 7 The parameter design values ​​of each lens in the eyepiece lens of this embodiment three are shown in Table 4:

[0073] Table 4 shows a design value for each lens in the eyepiece lens of Example 3.

[0074]

[0075] The surface numbers in Table 4 are assigned according to the surface sequence of each lens; "Object" represents the object plane of the eyepiece lens; "STO" represents the aperture stop of the eyepiece lens; "IMAGE" represents the image plane of the eyepiece lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; the thickness represents the central axial distance between the current surface and the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light; a blank space indicates that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface.

[0076] Figure 8 for Figure 7 The diagram shown is a dot plot of the eyepiece lens. A dot plot refers to the diffuse pattern formed by the aberrations of light rays emitted from a single light source. These rays, after passing through the optical system, no longer converge at a single point on the image plane, but instead form a scattered pattern over a certain area. The distribution of points in the dot plot can approximately represent the degree of concentration of the light rays and reflect the imaging quality of the system. For example... Figure 8 As shown, the diffusion patterns of light rays (0.436μm~0.656μm) are relatively concentrated in each field of view, indicating that the eyepiece lens has low chromatic aberration and aberration across the entire field of view, enabling high-resolution imaging.

[0077] Figure 9 for Figure 7 The diagram shows the field curvature distortion curve of the eyepiece lens. In the coordinate system on the left side of the diagram, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents the meridion and S represents the sagitta; from Figure 9 It can be seen that the eyepiece lens provided in this embodiment effectively controls the field curvature, that is, during imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of distortion, in percentage; the vertical axis represents the normalized image height, which has no unit; from Figure 9 As can be seen, the distortion of the lens provided in this embodiment has been well corrected, and the imaging distortion is small.

[0078] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A large exit pupil distance eyepiece lens, characterized in that, It includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the observation side to the display side; The first lens is a glass spherical lens with positive optical power, the second lens is a glass spherical lens with positive optical power, the third lens is a glass spherical lens with negative optical power, the fourth lens is a glass spherical lens with negative optical power, and the fifth lens is a glass spherical lens with positive optical power. The opposing surfaces of the second lens and the third lens are glued together to form a first cemented lens group.

2. The eyepiece lens according to claim 1, characterized in that, The opposing surfaces of the fourth lens and the fifth lens are glued together to form a second cemented lens group.

3. The eyepiece lens according to claim 1, characterized in that, The eyepiece lens satisfies the following condition: 0.41≤Φ1 / Φ≤0.7; Wherein, Φ1 is the optical power of the first lens, and Φ is the optical power of the eyepiece lens.

4. The eyepiece lens according to claim 1, characterized in that, The eyepiece lens satisfies the following condition: 1.91≤EL / TH≤3.09; Wherein, EL is the exit pupil distance of the eyepiece lens, and TH is the on-axis distance from the observation side surface of the first lens to the display side surface of the third lens.

5. The eyepiece lens according to claim 1, characterized in that, The second lens and the third lens satisfy the following condition: |vd2-vd3|≥26.2; Wherein, vd2 is the Abbe number of the second lens, and vd3 is the Abbe number of the third lens.

6. The eyepiece lens according to claim 1, characterized in that, The eyepiece lens satisfies the following condition: -1.52≤Φ3 / Φ≤-0.87; Wherein, Φ3 is the optical power of the third lens, and Φ is the optical power of the eyepiece lens.

7. The eyepiece lens according to claim 1, characterized in that, The eyepiece lens satisfies the following condition: -0.25≤Φ4 / Φ≤-0.02; Wherein, Φ4 is the optical power of the fourth lens, and Φ is the optical power of the eyepiece lens.

8. The eyepiece lens according to claim 1, characterized in that, The eyepiece lens satisfies the following condition: 0.61≤(|SAG21|+|SAG22|) / TH2≤0.97; Wherein, SAG21 is the sag at the maximum effective radius of the observation side surface of the second lens, SAG22 is the sag at the maximum effective radius of the display side surface of the second lens, and TH2 is the center thickness of the second lens.

9. The eyepiece lens according to claim 1, characterized in that, The eyepiece lens satisfies the following condition: 0.32≤(Φ4 / vd4+Φ5 / vd5)*1000≤0.74; Wherein, Φ4 is the optical power of the fourth lens, vd4 is the Abbe number of the fourth lens, Φ5 is the optical power of the fifth lens, and vd5 is the Abbe number of the fifth lens.

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