Low-distortion large-magnification all-plastic low-cost eyepiece

Abstract

The invention discloses a low-distortion large-magnification all-plastic low-cost eyepiece, and relates to the technical field of lenses, the eyepiece comprises an eyepiece body, the eyepiece body is internally provided with an optical system, the optical system is composed of a diaphragm STO, a first lens, a second lens, a third lens, protective glass and a screen, the first lens, the second lens, the third lens and the protective glass are all made of resin materials, the diaphragm STO is located at the exit pupil position of the eyepiece, the aperture diameter is 3 mm, and the diaphragm STO is used for controlling the clear aperture and the light beam emission angle. The low-distortion large-magnification all-plastic low-cost eyepiece disclosed by the invention has the technical effects of more compact overall design, lighter weight and lower production cost.

Description

Technical Field

[0001] This invention relates to the field of lens technology, and in particular to a low-distortion, high-magnification, all-plastic, low-cost eyepiece. Background Technology

[0002] In everyday use, eyepieces are commonly used in microscopes, aiming scopes, telescopes, and other fields. With the advent of small-sized displays, eyepieces can also be used to image displays, magnifying the content displayed on the display for human viewing.

[0003] However, some existing search and aiming eyepieces have large exit pupil diameters but low magnification, while those with high magnification can only be used with small screens. Eyepieces that meet both exit pupil diameter and magnification requirements have a large number of lenses, a relatively complex structure, and are relatively expensive. Therefore, there is an urgent need to develop a low-distortion, high-magnification, all-plastic, low-cost eyepiece to solve these problems.

[0004] For example, eyepieces that meet both exit pupil diameter and magnification requirements typically require a combination of glass spherical lenses. These traditional glass lenses require precision grinding and polishing, which is a complex process. Furthermore, multiple lenses (5-6 lenses) are needed to achieve high magnification and low distortion, resulting in high production costs. Summary of the Invention

[0005] This invention discloses a low-distortion, high-magnification, all-plastic, low-cost eyepiece, which aims to solve the technical problems of traditional eyepieces that meet both exit pupil diameter and magnification requirements, but have complex structures and high costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A low-distortion, high-magnification, all-plastic, low-cost eyepiece includes an eyepiece body, in which an optical system is provided. The optical system consists of an aperture stop (STO), a first lens, a second lens, a third lens, a protective glass, and a screen. The first lens, the second lens, the third lens, and the protective glass are all made of resin material.

[0007] In this solution, resin material is used instead of traditional glass material to make the first lens, second lens, third lens and protective glass. Compared with the traditional complex precision grinding and polishing process, resin material can be molded and formed. At the same time, the three-element lens structure is more compact, and the overall lens body is lighter and less expensive.

[0008] In a preferred embodiment, the aperture stop STO is located at the exit pupil of the eyepiece, and has an aperture diameter of 3 mm, used to control the light transmission aperture and the beam emission angle.

[0009] This enables effective control of the beam divergence angle and improves edge imaging uniformity.

[0010] In a preferred embodiment, the first lens has a radius of curvature ranging from 10 to 13 mm, a thickness ranging from 5.2 to 5.8 mm, and a refractive index ranging from 1.5 to 1.6; the second lens has a radius of curvature ranging from -10 to 13 mm and a thickness ranging from 2.7 mm; the third lens has a radius of curvature ranging from -5 to 2 mm and a thickness ranging from 4.2 to 4.8 mm; the eyepiece body has a focal length of 12.5 mm, an exit pupil distance of 20 mm, an exit pupil diameter of 6 mm, and a full field-of-view distortion ≤ 2.3%.

[0011] Setting the exit pupil distance to 20mm ensures comfortable viewing for the human eye and meets the wearing requirements of head-mounted devices. At the same time, the exit pupil diameter of 6mm provides sufficient light intake in low-light environments, improving brightness.

[0012] In a preferred embodiment, the distance between the first lens and the second lens is 0.8-1.2 mm, the distance between the second lens and the third lens is 1.5-2.0 mm, the surface of the protective glass is coated with an anti-reflection film with a light transmittance ≥98% and an anti-reflection wavelength range covering 480-650 nm, the display resolution adapted to the eyepiece body is ≥1280×1024 pixels, and the pixel size is 8-12 μm, and the thickness of the protective glass is in the range of 1.4-2.0 mm.

[0013] In addition, protective glass of a certain thickness can protect the internal lens when the eyepiece is in use, preventing it from being damaged.

[0014] As described above, a low-distortion, high-magnification, all-plastic, low-cost eyepiece includes an eyepiece body. The eyepiece body houses an optical system, which comprises an aperture stop (STO), a first lens, a second lens, a third lens, a protective glass, and a screen. The first lens, second lens, third lens, and protective glass are all made of resin material. The low-distortion, high-magnification, all-plastic, low-cost eyepiece provided by this invention offers the advantages of a more compact overall design, lighter weight, and lower production costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the optical system of a low-distortion, high-magnification, all-plastic, low-cost eyepiece proposed in this invention.

[0016] Figure 2 The distortion field curvature performance diagram is shown for a low-distortion, high-magnification, all-plastic, low-cost eyepiece proposed in this invention.

[0017] Figure 3 This is a relative illumination performance diagram of a low-distortion, high-magnification, all-plastic, low-cost eyepiece proposed in this invention.

[0018] Figure 4 The MTF performance diagram is shown for a low-distortion, high-magnification, all-plastic, low-cost eyepiece proposed in this invention.

[0019] In the diagram: 1. First lens; 2. Second lens; 3. Third lens; 4. Protective glass; 5. Screen. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] The low-distortion, high-magnification, all-plastic, low-cost eyepiece disclosed in this invention is mainly used in scenarios where traditional eyepieces that meet both exit pupil diameter and magnification requirements have complex structures and high costs.

[0022] Reference Figure 1 A low-distortion, high-magnification, all-plastic, low-cost eyepiece includes an eyepiece body, an optical system within the eyepiece body, and the optical system consists of an aperture stop STO, a first lens 1, a second lens 2, a third lens 3, a protective glass 4, and a screen 5. The first lens 1, the second lens 2, the third lens 3, and the protective glass 4 are all made of resin material.

[0023] In the eyepiece body of this solution, resin material is used instead of traditional glass material to make the first lens 1, the second lens 2, the third lens 3 and the protective glass 4. Compared with the traditional complex precision grinding and polishing process, resin material can be molded and formed. At the same time, the three-element lens structure is more compact, and the overall lens body is lighter and less expensive.

[0024] In particular, it should be noted that the lightweight advantage makes the eyepiece suitable for integration into portable devices such as drones and AR glasses.

[0025] The resin material used for the first lens 1, the second lens 2, and the third lens 3 is polycarbonate.

[0026] The aperture stop STO is located at the exit pupil of the eyepiece, with a diameter of 3mm. It is used to control the light-passing aperture and the beam emission angle, thereby effectively controlling the beam divergence angle and improving the uniformity of edge imaging.

[0027] It should be noted that, Figure 1 The diagram clearly depicts the process by which light rays start from the incident end, pass through a series of optical elements, and finally form a light spot or image at the receiving end. The densely packed light rays in the diagram represent light rays emitted from different incident angles or different object points.

[0028] Among them, the first lens 1 is a biconvex positive lens, the second lens 2 is a meniscus negative lens, and the third lens 3 is a meniscus positive lens. The radius of curvature of the first lens 1 is in the range of 10-13mm, the thickness is in the range of 5.2-5.8mm, and the refractive index is in the range of 1.5-1.6. The radius of curvature of the second lens 2 is in the range of -10-13mm, and the thickness is in the range of 2.7mm. The radius of curvature of the third lens 3 is in the range of -5-2mm, and the thickness is in the range of 4.2-4.8mm.

[0029] The eyepiece body has a focal length of 12.5mm, an exit pupil distance of 20mm, an exit pupil diameter of 6mm, and a full field-of-view distortion of ≤2.3%.

[0030] The 20mm exit pupil distance ensures comfortable viewing for the human eye and is suitable for wearing head-mounted devices. Meanwhile, the 6mm exit pupil diameter provides sufficient light intake in low-light environments, enhancing brightness.

[0031] It should be noted that the lens body of this solution allows for an eye movement range of ±5°, which can adapt to the differences in interpupillary distance among different users and expand the applicable population.

[0032] Reference Figure 1 In a preferred embodiment, the distance between the first lens 1 and the second lens 2 is 0.8-1.2 mm, the distance between the second lens 2 and the third lens 3 is 1.5-2.0 mm, the surface of the protective glass 4 is coated with an anti-reflection film with a light transmittance ≥98% and an anti-reflection wavelength range covering 480-650 nm, the display resolution adapted to the eyepiece body is ≥1280×1024 pixels, and the pixel size is 8-12 μm.

[0033] The thickness of the protective glass 4 is in the range of 1.4-2.0mm.

[0034] A protective glass of a certain thickness 4 can protect the internal lens from damage when the eyepiece body is in use.

[0035] Reference Figure 2 The field curvature and distortion curves visually demonstrate the aberration performance of the optical system in this scheme under different fields of view and wavelengths.

[0036] The curve in the figure shows a monotonic change, and the absolute value of the distortion rate increases with the increase of the field of view, which is a typical pincushion distortion; the distortion rate reaches a higher value at the edge of the field of view (such as 20.375°).

[0037] Reference Figure 3 The relative illumination performance shown reflects the uniformity of image illumination of the optical system at a magnification of 20X. In the central field of view (0~2.82 mm): the relative illumination decreases slowly from 1.0 to about 0.89, and the overall uniformity is good.

[0038] Reference Figure 4 This paper presents the diffraction modulation transfer function (MTF) curves of the optical system of this scheme at different spatial frequencies for multicolor light. It can be seen that the MTF is greater than 0.1 across the entire field of view for 50 line pairs. Figure 3 As can be seen from the image plane illumination, this solution has a higher magnification and higher image quality. When the human eye observes the screen through the eyepiece for a long time, it is less likely to cause fatigue and the user experience is better.

[0039] Working principle: This solution first replaces the traditional glass lens with a resin material. Compared to glass, resin is cheaper and lighter, resulting in a lighter and cheaper overall lens. Furthermore, while glass is typically expensive to manufacture aspherical lenses, resin can be molded, offering a more significant advantage. In addition, the eyepiece optical system of this invention has a magnification of 20X, an exit pupil distance of 20mm, an exit pupil diameter of 6mm, and optical distortion of less than 2.3, providing greater magnification and higher image quality.

[0040] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A low-distortion, high-magnification, all-plastic, low-cost eyepiece, comprising an eyepiece body, wherein an optical system is provided in the eyepiece body, characterized in that, The optical system consists of an aperture stop (STO), a first lens (1), a second lens (2), a third lens (3), a protective glass (4), and a screen (5). The first lens (1), the second lens (2), the third lens (3), and the protective glass (4) are all made of resin material.

2. The low-distortion, high-magnification, all-plastic, low-cost eyepiece according to claim 1, characterized in that, The resin material used for the first lens (1), the second lens (2), and the third lens (3) is polycarbonate.

3. The low-distortion, high-magnification, all-plastic, low-cost eyepiece according to claim 2, characterized in that, The aperture stop STO is located at the exit pupil of the eyepiece, with an aperture diameter of 3mm, and is used to control the light transmission aperture and the beam emission angle.

4. The low-distortion, high-magnification, all-plastic, low-cost eyepiece according to claim 3, characterized in that, The first lens (1) is a biconvex positive lens, the second lens (2) is a meniscus negative lens, and the third lens (3) is a meniscus positive lens.

5. The low-distortion, high-magnification, all-plastic, low-cost eyepiece according to claim 1, characterized in that, The first lens (1) has a radius of curvature ranging from 10 to 13 mm, a thickness ranging from 5.2 to 5.8 mm, and a refractive index ranging from 1.5 to 1.

6. The second lens (2) has a radius of curvature ranging from -10 to 13 mm and a thickness ranging from 2.7 mm. The third lens (3) has a radius of curvature ranging from -5 to 2 mm and a thickness ranging from 4.2 to 4.8 mm.

6. The low-distortion, high-magnification, all-plastic, low-cost eyepiece according to claim 5, characterized in that, The eyepiece body has a focal length of 12.5mm, an exit pupil distance of 20mm, an exit pupil diameter of 6mm, and a full field-of-view distortion of ≤2.3%.

7. The low-distortion, high-magnification, all-plastic, low-cost eyepiece according to claim 6, characterized in that, The distance between the first lens (1) and the second lens (2) is 0.8-1.2 mm, and the distance between the second lens (2) and the third lens (3) is 1.5-2.0 mm.

8. The low-distortion, high-magnification, all-plastic, low-cost eyepiece according to claim 1, characterized in that, The protective glass (4) is coated with an anti-reflective film with a light transmittance of ≥98% and an anti-reflection wavelength range covering 480-650nm.

9. A low-distortion, high-magnification, all-plastic, low-cost eyepiece according to claim 8, characterized in that, The eyepiece body is compatible with a display resolution of ≥1280×1024 pixels and a pixel size of 8-12μm.

10. A low-distortion, high-magnification, all-plastic, low-cost eyepiece according to claim 8, characterized in that, The thickness of the protective glass (4) is in the range of 1.4-2.0 mm.

Images