Optical structure, system and device for an eyepiece

Abstract

The application discloses an optical structure, a system and equipment of an ocular lens, the optical structure comprises five lenses, and the optical structure is sequentially arranged with a first lens, a second lens, a third lens, a fourth lens and a fifth lens in the direction of an optical axis from an object side to an image side. Wherein, the object side surface of the fifth lens is an even aspheric surface, and the image side surface is a binary surface. The focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens and the total focal length f of the optical structure satisfy the following relations: 0.1 < f / f1 < 0.5, 0.1 < f / f2 < 0.5, 0.5 < f / f3 < 1.5, -1.6 < f / f4 < -0.9, 0.9 < f / f5 < 1.5. By adopting the combination of the new optical surface type and the binary surface type, and under the condition that the focal lengths of the lenses and the lens groups satisfy specific conditions, the optical structure aberration is greatly eliminated, the sensitivity of each optical component is reduced, the imaging quality is good, and the long pupil distance is provided, so that the use is more convenient and comfortable, and the application can be widely applied in the field of optical technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical technology, in particular to an optical structure of an eyepiece, a system and a device. BACKGROUND

[0002] Eyepieces are commonly used in devices such as microscopes, sighting scopes, telescopes, etc. With the upgrading of production processes, the pixel points of displays are made smaller and smaller, and the volume of displays is also getting smaller and smaller, resulting in the emergence of small-volume displays of 0.4 inches and 0.5 inches. The traditional optical viewfinder on some devices cannot meet the demand of adding user interface elements on real-time images, and small displays are currently commonly used to replace them. Therefore, it is necessary to use an eyepiece to image the display and magnify the content displayed on the display for the human eye to view. In order to facilitate the user to wear goggles or glasses while still being able to normally use the eyepiece, the eyepiece needs to have a long exit pupil distance. In the prior art, the eyepiece optical system often has the defects of short exit pupil distance and poor imaging quality. SUMMARY

[0003] Therefore, the purpose of the embodiments of the present application is to provide an optical structure of an eyepiece, a system and a device, which have a long exit pupil distance and good imaging quality through reasonable optical structure design.

[0004] In a first aspect, the embodiments of the present application provide an optical structure of an eyepiece, which includes five lenses. The optical structure is arranged in the order of 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 the optical axis. The object side surface of the fifth lens is an even aspheric surface, and the image side surface is a binary surface. The focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens and the total focal length f of the optical structure satisfy any one or more of the following relationships:

[0005] 0.1 < f / f1 < 0.5

[0006] 0.1 < f / f2 < 0.5

[0007] 0.5 < f / f3 < 1.5

[0008] -1.6 < f / f4 < -0.9

[0009] 0.9 < f / f5 < 1.5

[0010] The third lens and the fourth lens are cemented into a cemented lens, and the focal length of the cemented lens is f6. f and f6 satisfy the following relationship: -0.1 < f / f6 < 0.

[0011] Optionally, the first lens has a positive optical power, the second lens has a positive optical power, the third lens has a positive optical power, the fourth lens has a negative optical power, and the fifth lens has a positive optical power.

[0012] Optionally, the first lens comprises a meniscus lens, the second lens comprises a meniscus lens, the third lens comprises a meniscus lens, the fourth lens comprises a meniscus lens, and the fifth lens comprises a double convex lens.

[0013] Optionally, the first lens has a radius of curvature that satisfies the following condition:

[0014] 30mm≤R1≤45mm

[0015] 70mm≤R2≤85mm

[0016] wherein R1 represents a radius of curvature of an object side surface of the first lens, and R2 represents a radius of curvature of an image side surface of the first lens.

[0017] Optionally, the second lens has a radius of curvature that satisfies the following condition:

[0018] 15mm≤R3≤30mm

[0019] 20mm≤R4≤35mm

[0020] wherein R3 represents a radius of curvature of an object side surface of the second lens, and R4 represents a radius of curvature of an image side surface of the second lens.

[0021] Optionally, the cemented lens has a radius of curvature that satisfies the following condition:

[0022] 15mm≤R5≤25mm

[0023] 115mm≤R6≤130mm

[0024] 10mm≤R7≤20mm

[0025] wherein R5 represents a radius of curvature of an object side surface of the third lens, R6 represents a radius of curvature of a cemented surface of the cemented lens, and R7 represents a radius of curvature of an image side surface of the fourth lens.

[0026] Optionally, the fifth lens has a radius of curvature that satisfies the following condition:

[0027] 15mm≤R8≤25mm

[0028] -25mm≤R9≤-15mm

[0029] wherein R8 represents a radius of curvature of an object side surface of the fifth lens, and R9 represents a radius of curvature of an image side surface of the fifth lens.

[0030] Optionally, the fifth lens is made of an optical resin material.

[0031] In a second aspect, an embodiment of the present application provides an optical system of an ocular, wherein the optical system is provided with the optical structure as described above.

[0032] In a third aspect, an embodiment of the present application provides an optical device of an ocular, wherein the optical device is provided with the optical system as described above.

[0033] The implementation of the embodiment of the present application has the following beneficial effects: the embodiment of the present application provides an optical structure of an ocular, which includes five lenses, and the optical structure is arranged in the order of a first lens, a second lens, a third lens, a fourth lens and a fifth lens in the direction of the optical axis from the object side to the image side; wherein the object side surface of the fifth lens is an even aspheric surface, and the image side surface is a binary surface; the focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens and the total focal length f of the optical structure satisfy the following relationships: 0.1<f / f1<0.5, 0.1<f / f2<0.5, 0.5<f / f3<1.5, -1.6<f / f4<-0.9, 0.9<f / f5<1.5; the third lens and the fourth lens are glued into a glued lens by ultraviolet light sensitive glue, and the focal length of the glued lens is f6, and f and f6 satisfy the following relationship: -0.1<f / f6<0. By adopting the combination of the new optical surface type and the binary surface type, and under the condition that the focal lengths of the lenses and the lens groups satisfy specific conditions, the structure aberration is greatly eliminated, the sensitivity of each optical component is reduced, the imaging quality of the optical structure is good, and the optical structure has a long exit pupil distance, which is more convenient and comfortable to use. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a structural schematic diagram of an optical structure of an ocular according to the first embodiment of the present application;

[0035] Figure 2 is an MTF curve diagram of the optical structure of the ocular according to the first embodiment of the present application;

[0036] Figure 3 is a field curvature and distortion curve diagram of the optical structure of the ocular according to the first embodiment of the present application;

[0037] Figure 4 is an axial aberration performance diagram of the optical structure of the ocular according to the first embodiment of the present application;

[0038] Figure 5 is a point spread diagram of the optical structure of the ocular according to the first embodiment of the present application;

[0039] Figure 6 This is a schematic diagram of the optical structure of an eyepiece according to Embodiment 2 of the present invention;

[0040] Figure 7 This is an MTF curve diagram of the optical structure of an eyepiece according to Embodiment 2 of the present invention;

[0041] Figure 8 This is a field curvature and distortion curve diagram of the optical structure of an eyepiece according to Embodiment 2 of the present invention;

[0042] Figure 9 This is an axial aberration performance diagram of the optical structure of an eyepiece according to Embodiment 2 of the present invention;

[0043] Figure 10 This is a dot diagram of the optical structure of an eyepiece according to Embodiment 2 of the present invention. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

[0045] Example 1

[0046] like Figure 1 As shown, Embodiment 1 of the present invention provides an optical structure for an eyepiece, comprising five lenses. The optical structure is arranged coaxially from the object side to the image side, consisting of a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), and a fifth lens (5). The object side (S8) of the fifth lens is an even-order aspherical surface, and the image side (S9) is a binary surface. The focal lengths f1 of the first lens, f2 of the second lens, f3 of the third lens, f4 of the fourth lens, f5 of the fifth lens, and the total focal length f of the optical structure satisfy any one or more of the following relationships:

[0047] 0.1 <f / f1<0.5

[0048] 0.1 <f / f2<0.5

[0049] 0.5 <f / f3<1.5

[0050] -1.6 <f / f4<-0.9

[0051] 0.9 <f / f5<1.5

[0052] The third lens and the fourth lens are cemented into a cemented lens, and a focal length of the cemented lens is f6, and f and f6 satisfy the following relationship: -0.1

[0053] The second lens provides most of the optical power of the optical structure; the third lens and the fourth lens are cemented into a cemented lens by ultraviolet light-sensitive cement; the object side surface (S5) of the third lens is a convex surface, and the image side surface (S7) of the fourth lens is a concave surface, and the cemented lens is used to correct aberrations.

[0054] The object side surface (S8) of the fifth lens is an even aspheric surface, used to correct aberrations; the image side surface (S9) is a binary surface, mainly used to correct chromatic aberration, and also has the effect of correcting aberrations.

[0055] Aspheric surface: the general spherical surface refers to the curvature of each point on the surface of the optical lens is fixed, while the aspheric surface has different curvatures at different positions.

[0056] Binary surface: a binary surface element is a kind of diffractive optical element, which essentially draws a plurality of concentric steps with different radii on the aspheric surface, and has the characteristics of negative chromatic aberration and negative thermal aberration.

[0057] The stop (STO) is located at the exit pupil position, and the protective glass (6) is located at the image side surface of the fifth lens.

[0058] Specifically, the light ray enters the first lens from the stop, wherein the first lens is a meniscus lens with positive optical power, and then enters the second lens, wherein the second lens is a meniscus concave lens with positive optical power, which provides most of the optical power of the optical structure; the light ray enters the cemented lens composed of the third lens and the fourth lens after the optical power compensation of the second lens, wherein the third lens is a meniscus lens with positive optical power, and the fourth lens is a meniscus lens with negative optical power, the object side surface of the third lens is a convex surface, and the image side surface of the fourth lens is a concave surface, and the cemented lens is used to correct aberrations; the light ray enters the fifth lens after the correction of aberrations by the cemented lens, wherein the object side surface of the fifth lens is an even aspheric surface, used to correct aberrations; the image side surface is a binary surface, mainly used to correct chromatic aberration, and also has the effect of correcting aberrations; the light ray enters the protective glass after the correction of aberrations and chromatic aberration by the fifth lens, and then completes imaging.

[0059] Specifically, in the optical structure, the binary surface profile satisfies the following formula:

[0060]

[0061] wherein is the phase of light, is the diffraction order, is the number of polynomial coefficients in the technology, is where the coefficients of 2i are the normalized aperture coordinates. By filling in the appropriate values in the formula, one can define multiple diffraction steps - annuli - on the lens surface. Table 1 shows the parameters for each binary surface in the first embodiment of the application:

[0062] Table 1 Parameters for each binary surface in the first embodiment of the application

[0063]

[0064] Optionally, the first lens has positive optical power, the second lens has positive optical power, the third lens has positive optical power, the fourth lens has negative optical power, and the fifth lens has positive optical power.

[0065] Optionally, the first lens comprises a meniscus lens, the second lens comprises a meniscus lens, the third lens comprises a meniscus lens, the fourth lens comprises a meniscus lens, and the fifth lens comprises a double convex lens.

[0066] Optionally, the first lens has a radius of curvature that satisfies the following condition:

[0067] 30mm≤R1≤45mm

[0068] 70mm≤R2≤85mm

[0069] where R1 represents the radius of curvature of the object side surface of the first lens, and R2 represents the radius of curvature of the image side surface of the first lens.

[0070] Optionally, the second lens has a radius of curvature that satisfies the following condition:

[0071] 15mm≤R3≤30mm

[0072] 20mm≤R4≤35mm

[0073] where R3 represents the radius of curvature of the object side surface of the second lens, and R4 represents the radius of curvature of the image side surface of the second lens.

[0074] Optionally, the third lens has a radius of curvature that satisfies the following condition:

[0075] 15mm≤R5≤25mm

[0076] 115mm≤R6≤130mm

[0077] 10mm≤R7≤20mm

[0078] where R5 represents the radius of curvature of the object side surface of the third lens, R6 represents the radius of curvature of the cemented surface of the cemented lens, and R7 represents the radius of curvature of the image side surface of the fourth lens.

[0079] Optionally, the radius of curvature of the fifth lens satisfies the following condition:

[0080] 15mm≤R8≤25mm

[0081] -25mm≤R9≤-15mm

[0082] wherein R8 represents the radius of curvature of the object side surface of the fifth lens, and R9 represents the radius of curvature of the image side surface of the fifth lens.

[0083] Specifically, referring to Table 2, the parameters of the optical structure of the eyepiece in Embodiment One of the present application, and referring to Table 3, the conic coefficients and high-order coefficients of the even aspherical surfaces in Embodiment One of the present application: Figure 1

[0084] Table 2: Parameters of the optical structure of the eyepiece in Embodiment One of the present application

[0085]

[0086] Specifically, the radius of curvature of the object side surface of the first lens is 70mm~85mm, the thickness is 0mm~0.5mm, the refractive index is 1.8Nd~1.9Nd, and the Abbe number is 38Vd~48Vd; the radius of curvature of the image side surface of the first lens is 70mm~85mm, the thickness is 0mm~0.5mm; the radius of curvature of the object side surface of the second lens is 15mm~30mm, the thickness is 4.3mm~4.9mm, the refractive index is 1.9Nd~2.1Nd, and the Abbe number is 20Vd~30Vd; the radius of curvature of the image side surface of the second lens is 20mm~35mm, the thickness is 0mm~0.5mm; the radius of curvature of the object side surface of the cemented lens is 15mm~25mm, the thickness is 8.1mm~8.7mm, the refractive index is 1.8Nd~2.0Nd, and the Abbe number is 35Vd~45Vd; the radius of curvature of the cemented surface of the cemented lens is 115mm~130mm, the thickness is 1.5mm~2.0mm, the refractive index is 1.9Nd~2.1Nd, and the Abbe number is 10Vd~20Vd; the radius of curvature of the image side surface of the cemented lens is 10mm~20mm, the thickness is 2.3mm~3.0mm; the radius of curvature of the object side surface of the fifth lens is 15mm~25mm, the thickness is 4.5mm~5.0mm, the refractive index is 1.4Nd~1.6Nd, and the Abbe number is 50Vd~60Vd; the radius of curvature of the image side surface of the fifth lens is -25mm~-15mm, the thickness is 4.5mm~5.0mm.

[0087] In the optical structure, each even aspherical surface satisfies the following formula:

[0088]

[0089] ​Wherein, f is the height of the even aspheric surface along the optical axis direction in the position of h, the distance from the vertex of the even aspheric surface, R is the curvature of the even aspheric surface, k is the conic coefficient, A, B, C are all high order coefficients, the following table is the conic coefficient and high order coefficient of each even aspheric surface in the embodiment one of the application:

[0090] Table 3 the conic coefficient and high order coefficient of even aspheric surface in the embodiment one of the application

[0091]

[0092] Optionally, the material of the fifth lens comprises optical resin material.

[0093] Specifically, the fifth lens 5 uses optical resin material, through reasonable selection of material, the ocular lens has the characteristics of light weight, easy processing and low cost.

[0094] In one specific embodiment, the ratio of the exit pupil distance of the optical structure to the total focal length of the optical structure is between 2.75 and 3.25, the magnification is 10-13 times, the exit pupil distance of the optical structure is 55-65mm, the exit pupil diameter of the optical structure is 6mm, the total focal length of the optical structure is 20-25mm, the allowed eye movement range is ±5D, the working wavelength is 480-650nm, the display size is 0.4 inches, and the MTF at 50lp / mm is 0.1.

[0095] Referring to Figure 2 , the MTF curve of the optical structure of the ocular lens in the embodiment one of the application: Figure 2 The MTF curve of the optical structure of the ocular lens in the embodiment one of the application, the horizontal coordinate is spatial frequency, unit is per millimeter line logarithm, the vertical coordinate is MTF value, MTF (Modulation Transfer Function, modulation transfer function) can reflect the imaging quality of the optical structure, the smoother the MTF curve transition is, the better the imaging quality of the optical structure is. As can be seen from the figure, the MTF of the optical structure at 50lp / mm spatial frequency in the edge field reaches 0.13, which has good contrast and meets the requirements of human eye observation.

[0096] Referring to Figure 3 , the field curvature and distortion curve of the optical structure of the ocular lens in the embodiment one of the application: Figure 3The figures show the field curvature and distortion curves of the eyepiece optical structure in Embodiment 1 of this invention under three different wavelengths of light: 486nm (A), 587nm (B), and 656nm (C). The vertical axis represents the field of view. Field curvature is an aberration in the formation of a curved image from an object plane, characterized by meridional and sagittal field curvatures. Excessive curvature in either severely affects the off-axis ray imaging quality of the optical structure. When the distortion of the structure is less than 4%, it is difficult for the human eye to perceive. As can be seen from the figures, the maximum field curvature of this optical structure at a wavelength of 587nm is approximately 0.15, and the maximum distortion is approximately 3%, indicating relatively small distortion that is difficult to detect.

[0097] Reference Figure 4 Axial aberration performance diagram of the optical structure of an eyepiece according to Embodiment 1 of the present invention: Figure 4 This is an axial aberration performance diagram of the optical structure of the eyepiece in Embodiment 1 of the present invention. The horizontal axis of the diagram represents the position difference, and the vertical axis represents the entrance pupil radius. The diagram describes the magnitude and trend of spherical aberration at different wavelengths (486nm, 587nm, 656nm) and different pupil sizes. As can be seen from the diagram, the spherical aberration of this optical structure is relatively small, at ±0.08mm.

[0098] Reference Figure 5 The dot plot of an eyepiece optical structure according to Embodiment 1 of the present invention reflects the geometric structure of the optical structure for imaging. In image quality evaluation, the density of the dot plot can intuitively reflect the quality of the image. The smaller the RMS radius and the more rounded the shape in the dot plot, the smaller the aberrations and the better the imaging quality of the structure. As can be seen from the figure, the dot plot of this optical structure is relatively round, the RMS radius is small (within 0.015 mm), and the variation in the RMS radius does not exceed 0.008 mm, indicating good aberration correction and good imaging quality of the optical structure.

[0099] The embodiment one of the present application has the following beneficial effects: the embodiment one of the present application provides an optical structure of an ocular lens, which includes five lenses, and the optical structure is arranged in sequence along an optical axis direction from an object side to an image side, and the five lenses are a first lens, a second lens, a third lens, a fourth lens and a fifth lens; wherein the object side surface of the fifth lens is an even aspheric surface, and the image side surface of the fifth lens is a binary surface; the focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens and the total focal length f of the optical structure satisfy the following relationships: 0.1 < f / f1 < 0.5, 0.1 < f / f2 < 0.5, 0.5 < f / f3 < 1.5, -1.6 < f / f4 < -0.9, 0.9 < f / f5 < 1.5; the third lens and the fourth lens are glued into a glued lens by ultraviolet light sensitive glue, the focal length of the glued lens is f6, and f and f6 satisfy the following relationship: -0.1 < f / f6 < 0. By adopting the combination of the new optical surface type and the binary surface type, and by satisfying the specific conditions of the focal lengths of the lenses and the lens groups, the optical structure aberration is greatly eliminated, the sensitivity of each optical component is reduced, the imaging quality is good, and the ocular lens has a long exit pupil distance, and is more convenient and comfortable to use.

[0100] By adopting the resin material, the cost of the ocular lens is lower, the quality is lighter, the quality of the entire lens is lighter, and the price is lower; by using the binary surface to correct chromatic aberration, the chromatic aberration of the optical structure of the ocular lens is smaller than that of a general ocular lens; the exit pupil distance of the ocular lens optical structure of the present application reaches 60-65mm, which is an ultra-long exit pupil distance ocular lens, and is more convenient to use in the scene of installing an eye shield, wearing glasses or goggles and the like.

[0101] Embodiment two

[0102] As Figure 6As shown, the second embodiment of the present application provides an optical structure of an objective lens, which includes six lenses. The optical structure is arranged in the order of a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5) and a sixth lens (6) along the optical axis direction from the object side to the image side. The object side surface (S9) of the sixth lens is an even aspheric surface, and the image side surface (S10) is a biaxial surface. The focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens, the focal length f6 of the sixth lens and the total focal length f of the optical structure satisfy any one or more of the following relationships: -0.05 < f / f1 < 0; 0.13 < f / f2 < 0.23; 0.28 < f / f3 < 0.38; 0.8 < f / f4 < 0.9; -1.5 < f / f5 < -0.5; 0.9 < f / f6 < 1.0. The focal length of the cemented lens composed of the first lens 1 and the second lens 2 is f7, and the focal length of the cemented lens composed of the fourth lens 4 and the fifth lens 5 is f8. The relationship between f and f7 is 0.13 < f / f7 < 0.23, and the relationship between f and f8 is -0.05 < f / f8 < 0.

[0103] The first lens and the second lens are cemented into a cemented lens by ultraviolet light sensitive cement, and the optical power is positive. The first lens is a plano-convex lens, and the optical power is positive. The object side surface is a plane, and the image side surface is a convex surface. The second lens is a negative meniscus lens, and the optical power is negative. The object side surface is a concave surface, and the image side surface is a convex surface. The cemented lens is used to correct aberration.

[0104] The third lens is a meniscus lens, and the optical power is positive, which provides most of the optical power of the optical system.

[0105] The fourth lens and the fifth lens are cemented into a cemented lens by ultraviolet light sensitive cement, and the optical power is negative. The fourth lens is a meniscus lens, and the optical power is positive. The object side surface is a convex surface, and the image side surface is a concave surface. The fifth lens is a meniscus lens, and the optical power is negative. The object side surface is a convex surface, and the image side surface is a concave surface. The cemented lens is used to correct aberration.

[0106] The sixth lens is a double-convex lens, and the optical power is positive. The object side surface is an even aspheric surface, and the image side surface is a biaxial surface. The even aspheric surface is used to correct aberration, and the biaxial surface is mainly used to correct chromatic aberration, and also has the effect of correcting aberration. The optical resin material is adopted, which has the characteristics of light weight, easy processing and low cost.

[0107] The sixth lens is followed by a protective glass (7).

[0108] Specifically, referring to Figure 6, referring to Table 4 for parameters of the optical structure of the eyepiece in Embodiment Two of the present application, referring to Table 5 for conic coefficients and high-order coefficients of the even aspherical surface in Embodiment Two of the present application, and referring to Table 6 for parameters of each binary surface in Embodiment Two of the present application:

[0109] Table 4 for parameters of the optical structure of the eyepiece in Embodiment One of the present application

[0110]

[0111] The even aspherical surface satisfies the following formula:

[0112]

[0113] wherein f is the sag of the even aspherical surface at a height of h along the optical axis, R is the curvature of the even aspherical surface, k is the conic coefficient, and the 2n-th order even aspherical surface coefficients are .

[0114] Table 5 for conic coefficients and high-order coefficients of the even aspherical surface in Embodiment Two of the present application

[0115]

[0116] Table 6 for parameters of each binary surface in Embodiment Two of the present application

[0117]

[0118] In one specific embodiment, the ratio of the exit pupil distance of the optical structure to the total focal length of the optical structure is between 2.2 and 2.9, the exit pupil distance of the optical structure is 50-60 mm, the exit pupil diameter of the optical structure is 6 mm, the total focal length of the optical structure is 20.8-21.2 mm, the allowable eye movement range is ±5D, the working wavelength is 480-650 nm, the display size is 0.5 inches, and the MTF at 50 lp / mm is 0.2.

[0119] Referring to Figure 7 , the MTF curve of the optical structure of the eyepiece in Embodiment Two of the present application: the MTF curve of the eyepiece optical structure in Embodiment Two of the present application, wherein the abscissa is the spatial frequency, the unit is the logarithm of the line per millimeter, and the ordinate is the MTF value. The MTF can reflect the imaging quality of the optical structure. The smoother the MTF curve transition is, the better the imaging quality of the optical structure is. As can be seen from the figure, the MTF of the optical structure at the edge of the field of view reaches 0.23 at a spatial frequency of 30 lp / mm, has good contrast, and meets the requirements of human eye observation.

[0120] Referring to Figure 8A field curvature and distortion curve diagram of an optical structure of an eyepiece of the second embodiment of the present application: the field curvature and distortion curve of the eyepiece optical structure of the second embodiment of the present application at three different wavelengths of light, 486nm (A), 587nm (B), and 656nm (C), respectively, wherein the vertical coordinate is the field angle. Field curvature is a kind of aberration of the object plane forming a curved image, and is characterized by meridional and sagittal field curvature. If the two are too large, the imaging quality of the optical structure will be seriously affected. When the distortion of the structure is less than 4%, the human eye is difficult to detect. As can be seen from the figure, the maximum value of the field curvature of the optical structure at a wavelength of 587nm is about 0.17, and the maximum value of the distortion is about 3.1%, so the distortion is small and difficult to detect.

[0121] Referring to Figure 9 An axial aberration performance diagram of the optical structure of the eyepiece of the second embodiment of the present application: the axial aberration performance diagram of the optical structure of the second embodiment of the present application, wherein the horizontal coordinate is the position difference, and the vertical coordinate is the entrance pupil radius. The diagram describes the size and variation trend of the spherical aberration at different wavelengths (486nm, 587nm, 656nm) and different pupil sizes. As can be seen from the diagram, the spherical aberration of the optical structure is small, ±0.1mm.

[0122] Referring to Figure 10 A point diagram of the optical structure of the eyepiece of the second embodiment of the present application: as can be seen from the diagram, the point diagram of the optical structure is relatively round, the RMS radius is within 0.015mm, the change amount of the RMS radius is not more than 0.008mm, the aberration correction is good, and the imaging quality of the optical structure is good.

[0123] The embodiment two of the present application has the following beneficial effects: the embodiment two of the present application provides an optical structure of an ocular lens, which includes six lenses, and the optical structure is sequentially arranged with a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens in the direction of the optical axis from the object side to the image side; wherein the object side surface of the sixth lens is an even aspheric surface, and the image side surface is a binary surface; the focal length f1 of the first lens, the focal length f2 of the second lens, the focal length f3 of the third lens, the focal length f4 of the fourth lens, the focal length f5 of the fifth lens, the focal length f6 of the sixth lens and the total focal length f of the optical structure satisfy any one or more of the following relationships: -0.05 < f / f1 < 0; 0.13 < f / f2 < 0.23; 0.28 < f / f3 < 0.38; 0.8 < f / f4 < 0.9; -1.5 < f / f5 < -0.5; 0.9 < f / f6 < 1.0. The focal length of the cemented lens composed of the first lens and the second lens is f7, and the focal length of the cemented lens composed of the fourth lens and the fifth lens is f8, then f and f7 have the following relationship: 0.13 < f / f7 < 0.23, and f and f8 have the following relationship: -0.05 < f / f8 < 0. By adopting the combination of the even aspheric surface and the binary surface, the cementing of the lenses, and the focal lengths of the lenses and the cemented lenses satisfying specific conditions, the optical structure aberration is greatly eliminated, the sensitivity of each optical component is reduced, the imaging quality is good, and the ocular lens has a long exit pupil distance, which is more convenient and comfortable to use.

[0124] The ocular lens optical structure of the embodiment two of the present application is suitable for a larger 0.5-inch display; the use of resin material has lower cost and lighter weight, so that the whole lens has lighter weight and lower price; the use of the binary surface to correct chromatic aberration makes the chromatic aberration of the optical structure smaller; the exit pupil distance of the ocular lens optical structure reaches 50-60 mm, which is a long exit pupil distance ocular lens, and is more convenient to use in the scene of installing an eye shield, wearing glasses or goggles, etc.

[0125] Embodiment three

[0126] An optical system of an ocular lens, wherein the optical system is provided with the optical structure as described above, in addition to which the optical system further includes a display (p) for displaying an image.

[0127] It can be seen that the above optical structure embodiments are all suitable for the optical system embodiments, the functions of the optical system embodiments are the same as those of the above optical structure embodiments, and the beneficial effects achieved by the optical system embodiments are also the same as those achieved by the above optical structure embodiments.

[0128] Embodiment four

[0129] An optical device of an ocular lens, wherein the optical device is provided with the optical system as described above, in addition to which the optical device further includes a fixing or dismounting device which can be used for head wearing or hand holding.

[0130] It can be seen that the above optical system embodiments are all applicable to the present optical device embodiment, the present optical device embodiment specifically implements the same functions as the above optical system embodiments, and achieves the same beneficial effects as the above optical system embodiments.

[0131] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

1. An optical structure for an eyepiece, characterized in that, The optical structure consists of five lenses, arranged sequentially along the optical axis from the object side to the image side: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The object side of the fifth lens is an even-order aspherical surface, and the image side is a binary surface. The focal lengths f1 of the first lens, f2 of the second lens, f3 of the third lens, f4 of the fourth lens, f5 of the fifth lens, and the total focal length f of the optical structure satisfy the following relationship: 0.1 <f / f1<0.5 0.1 <f / f2<0.5 0.5 <f / f3<1.5 -1.6 <f / f4<-0.9 0.9 <f / f5<1.5 The third lens and the fourth lens are cemented together to form a cemented lens. The focal length of the cemented lens is f6. Then, f and f6 satisfy the following relationship: -0.1 <f / f6<0。 2. The optical structure according to claim 1, characterized in that, The first lens includes a meniscus, the second lens includes a meniscus, the third lens includes a meniscus lens, the fourth lens includes a meniscus lens, and the fifth lens includes a biconvex lens.

3. The optical structure according to claim 1, characterized in that, The radius of curvature of the first lens satisfies the following condition: 30mm≤R1≤45mm 70mm≤R2≤85mm Wherein, R1 represents the radius of curvature of the object side of the first lens, and R2 represents the radius of curvature of the image side of the first lens.

4. The optical structure according to claim 1, characterized in that, The radius of curvature of the second lens satisfies the following condition: 15mm≤R3≤30mm 20mm≤R4≤35mm Wherein, R3 represents the radius of curvature of the object side of the second lens, and R4 represents the radius of curvature of the image side of the second lens.

5. The optical structure according to claim 1, characterized in that, The radius of curvature of the cemented lens satisfies the following condition: 15mm≤R5≤25mm 115mm≤R6≤130mm 10mm≤R7≤20mm Wherein, R5 represents the radius of curvature of the object-side surface of the third lens, R6 represents the radius of curvature of the cemented surface of the cemented lens, and R7 represents the radius of curvature of the image-side surface of the fourth lens.

6. The optical structure according to claim 1, characterized in that, The radius of curvature of the fifth lens satisfies the following condition: 15mm≤R8≤25mm -25mm≤R9≤-15mm Wherein, R8 represents the radius of curvature of the object side of the fifth lens, and R9 represents the radius of curvature of the image side of the fifth lens.

7. The optical structure according to any one of claims 1-6, characterized in that, The fifth lens is made of optical resin.

8. An optical system for an eyepiece, characterized in that, The optical system is provided with an optical structure as described in any one of claims 1-7.

9. An optical device for an eyepiece, characterized in that, The optical device is provided with the optical system as described in claim 8.

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