Large-field-of-view head-mounted optical system

Abstract

The large-view-field head-mounted optical system comprises an objective optical system, a movement module and an eyepiece optical system, the objective optical system is detachably connected with the movement module and located on one side of the movement module, and the other side of the movement module is detachably connected with the eyepiece optical system; the objective optical system comprises a first spherical lens, a second spherical lens, a third spherical lens, a fourth spherical lens, a doublet lens and a first aspheric lens which are sequentially arranged from the object side to the image side in the optical axis direction. The eyepiece optical system comprises a second aspheric lens, a seventh spherical lens and an eighth spherical lens, and the second aspheric lens, the seventh spherical lens and the eighth spherical lens are sequentially arranged from the eye point side to the object side in the optical axis direction. The large-view-field head-mounted optical system solves the problem that the large view field, high imaging quality, small size and light weight are difficult to meet at the same time, and can be widely applied to the low-light night vision field or the night vision head-mounted field.

Description

Technical Field

[0001] The invention belongs to the technical field of digital low-light-level night vision equipment and optical elements, and in particular relates to a head-mounted optical system with a large field of view. Background Art

[0002] Digital night vision equipment usually uses low-light CCD / CMOS, EBAPS devices and other core components, combined with eyepiece and objective optical systems, to achieve the acquisition and observation of night vision scenes. Digital night vision optical systems are head-mounted optical systems. In order to reduce the feeling of dizziness, they are generally required to be small in size, light in weight, with a large field of view and high imaging quality. The eyepiece and objective optical systems of existing digital night vision equipment have a relatively small observation field range, generally covering a maximum field of view angle of only 45°~50°, and the eyepiece and objective optical systems are relatively large in size and heavy in weight.

[0003] The field of view and imaging quality of night vision eyepieces and objective optical systems are directly related to their volume and weight. To achieve high-quality imaging, a multi-lens combination design is generally required to achieve high-resolution, low-distortion imaging effects; to achieve a large field of view of more than 50° while ensuring imaging quality, a long focal length, large aperture, and multi-lens combination design are generally required; all of which will increase the volume and weight of the eyepiece and objective optical system. How to resolve the contradiction between field of view size, imaging quality, volume, and weight, and to achieve an eyepiece and objective optical system with a large field of view, high imaging quality, small volume, and light weight is a difficult problem that urgently needs to be broken through. Summary of the invention

[0004] The purpose of the present invention is to provide a head-mounted optical system with a large field of view, which solves the problem of insufficient large field of view and high imaging quality of existing night vision eyepieces and objective lens optical systems by combining spherical lenses and aspherical lenses.

[0005] The technical solution adopted by the present invention is a head-mounted optical system with a large field of view, comprising an objective optical system, a core module and an eyepiece optical system, wherein the objective optical system is detachably connected to the core module and is located on one side of the core module, and the other side of the core module is detachably connected to the eyepiece optical system; The objective optical system comprises a first spherical lens, a second spherical lens, a third spherical lens, a fourth spherical lens, a doublet lens and a first aspherical lens which are arranged in sequence from the object side to the image side along the optical axis; The eyepiece optical system comprises a second aspherical lens, a seventh spherical lens and an eighth spherical lens, which are arranged in sequence from the eye point side to the object side along the optical axis.

[0006] The technical solution of the present invention is also characterized in that: The first spherical lens and the seventh spherical lens are both concave-convex lenses, the second spherical lens, the third spherical lens, the fourth spherical lens and the eighth spherical lens are all convex lenses, and the first aspherical lens and the second aspherical lens are both plano-convex lenses.

[0007] The doublet lens comprises a fifth spherical lens and a sixth spherical lens. The fifth spherical lens is close to the fourth spherical lens. Both the fifth spherical lens and the sixth spherical lens are convex lenses.

[0008] The first spherical lens is made of optical glass H-ZF62, the second spherical lens and the fifth spherical lens are made of optical glass H-ZF88, the third spherical lens is made of optical glass H-K9L, the fourth spherical lens is made of optical glass H-LAF2, the sixth spherical lens is made of optical glass H-ZLAF52A, and the first aspherical lens is made of optical glass H-ZLAF68C.

[0009] The relative aperture of the objective optical system is between 1:1.4 and 1:1.6, the total length of the objective optical system does not exceed 60mm, the focal length does not exceed 15mm, and the total weight does not exceed 45g; The horizontal field of view of the objective optical system is not less than 50°, the vertical field of view is not less than 35°, and the distortion within the overall field of view of the objective optical system is not more than 5%; The imaging resolution of the objective optical system is not less than 800lp / mm, and the clear imaging range is 250mm~infinity; The working band of the objective optical system covers visible light to near infrared.

[0010] The second aspherical lens is made of optical glass H-LA52, the seventh spherical lens is made of optical glass H-ZLAF68C, and the eighth spherical lens is made of optical glass H-ZF88.

[0011] The exit pupil distance of the eyepiece optical system shall not be less than 15mm, and the exit pupil diameter shall not be less than 4mm; the focal length of the eyepiece optical system shall not be greater than 20mm, the total length of the eyepiece optical system shall not be greater than 30mm, and the total weight shall not be greater than 50g; The distortion within the overall field of view of the eyepiece optical system is no more than 5%; The working band of the eyepiece optical system covers visible to near infrared; The objective optical system and the eyepiece optical system can be used alone or in combination.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) The large-field-of-view head-mounted optical system provided by the present invention is based on universal optical glass materials. By optimizing the design of a combination of spherical lenses and aspherical lenses, the system solves the problem of simultaneously satisfying the requirements of large field of view, high imaging quality, small size, and light weight. The system can be widely used in the field of low-light-level night vision or night vision head-mounted optical systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic structural diagram of a head-mounted optical system with a large field of view according to the present invention; Figure 2 is a distortion diagram of the objective optical system of Example 6 of the present invention; Figure 3 is a dispersion pattern of the objective optical system of Example 6 of the present invention; Figure 4 is an optical transfer function diagram of the objective optical system of Example 6 of the present invention; Figure 5 is a distortion diagram of the eyepiece optical system of Example 6 of the present invention; Figure 6 is a dispersion pattern of the eyepiece optical system of Example 6 of the present invention; Figure 7 2 is an optical transfer function diagram of the eyepiece optical system of Example 6 of the present invention.

[0014] In the figure, 1. the first spherical lens, 2. the second spherical lens, 3. the third spherical lens, 4. the fourth spherical lens, 5. the fifth spherical lens, 6. the sixth spherical lens, 7. the first aspherical lens, 8. the second aspherical lens, 9. the seventh spherical lens, 10. the eighth spherical lens, 11. the movement module. DETAILED DESCRIPTION

[0015] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] The present invention provides a head-mounted optical system with a large field of view, such as Figure 1 As shown, it includes an objective optical system, a movement module 11 and an eyepiece optical system. The objective optical system is detachably connected to the movement module 11 and is located on one side of the movement module 11, and the other side of the movement module 11 is detachably connected to the eyepiece optical system; the objective optical system includes a first spherical lens 1, a second spherical lens 2, a third spherical lens 3, a fourth spherical lens 4, a doublet lens and a first aspherical lens 7, which are arranged in sequence from the object side to the image side along the optical axis.

[0017] Among them, the double cemented lens includes a fifth spherical lens 5 and a sixth spherical lens 6, the fifth spherical lens 5 is close to the fourth spherical lens 4, the first spherical lens 1 is a concave-convex lens, the second spherical lens 2, the third spherical lens 3, the fourth spherical lens 4, the fifth spherical lens and the sixth spherical lens are all convex lenses, the first aspherical lens 7 is a plano-convex lens, the movement module 11 includes a shell, a sensor, a processing board and a display screen are arranged in the shell, the sensor is used to receive external light collected by the eyepiece optical system and convert it into an electrical signal, the processing board converts the transmitted electrical signal into an analog-to-digital signal, and performs image processing, the processed image is output to the display screen, and the eyepiece optical system observes the image on the display screen.

[0018] The first spherical lens 1 is made of optical glass H-ZF62, the second spherical lens 2 and the fifth spherical lens 5 are made of optical glass H-ZF88, the third spherical lens 3 is made of optical glass H-K9L, the fourth spherical lens 4 is made of optical glass H-LAF2, the sixth spherical lens 6 is made of optical glass H-ZLAF52A, and the first aspherical lens 7 is made of optical glass H-ZLAF68C.

[0019] The relative aperture of the objective optical system is between 1:1.4 and 1:1.6, the total length of the objective optical system does not exceed 60mm, the focal length does not exceed 15mm, and the total weight does not exceed 45g; the horizontal field of view of the objective optical system is not less than 50°, the vertical field of view is not less than 35°, and the distortion within the overall field of view of the objective optical system is not more than 5%; the imaging resolution of the objective optical system is not less than 800lp / mm, and the clear imaging range is 250mm~infinity; the working band of the objective optical system covers visible light~near infrared.

[0020] The eyepiece optical system includes a second aspherical lens 8, a seventh spherical lens 9 and an eighth spherical lens 10, which are arranged in sequence from the eye point side to the object side along the optical axis.

[0021] Among them, the second aspheric lens 8 is a plano-convex lens, the seventh spherical lens 9 is a meniscus lens, the eighth spherical lens 10 is a convex lens, the second aspheric lens 8 is made of optical glass H-LA52, the seventh spherical lens 9 is made of optical glass H-ZLAF68C, and the eighth spherical lens 10 is made of optical glass H-ZF88.

[0022] The pupil distance of the eyepiece optical system shall not be less than 15mm, and the pupil diameter shall not be less than 4mm; the focal length of the eyepiece optical system shall not be greater than 20mm, the total length of the eyepiece optical system shall not be greater than 30mm, and the total weight shall not be greater than 50g. The distortion within the overall field of view of the eyepiece optical system shall not be greater than 5%. The working band of the eyepiece optical system covers visible to near infrared. The objective optical system and the eyepiece optical system can be used separately or in combination.

[0023] Example 1 This embodiment provides a head-mounted optical system with a large field of view, such as Figure 1 As shown, it includes an objective optical system, a movement module 11 and an eyepiece optical system. The objective optical system is detachably connected to the movement module 11 and is located on one side of the movement module 11, and the other side of the movement module 11 is detachably connected to the eyepiece optical system; the objective optical system includes a first spherical lens 1, a second spherical lens 2, a third spherical lens 3, a fourth spherical lens 4, a doublet lens and a first aspheric lens 7, which are arranged in sequence from the object side to the image side along the optical axis direction; the first spherical lens 1 and the seventh spherical lens 9 are both concave-convex lenses, the second spherical lens 2, the third spherical lens 3, the fourth spherical lens 4 and the eighth spherical lens 10 are all convex lenses, and the first aspheric lens 7 and the second aspheric lens 8 are both plano-convex lenses.

[0024] The eyepiece optical system includes a second aspherical lens 8, a seventh spherical lens 9 and an eighth spherical lens 10, which are arranged in sequence from the eye point side to the object side along the optical axis.

[0025] Example 2 On the basis of Example 1, the double cemented lens includes a fifth spherical lens 5 and a sixth spherical lens 6, the fifth spherical lens 5 is close to the fourth spherical lens 4, and the fifth spherical lens 5 and the sixth spherical lens 6 are both convex lenses. The core module 1111 includes a housing, in which a sensor, a processing board and a display screen are arranged, the sensor is used to receive the external light collected by the eyepiece optical system and convert it into an electrical signal, the processing board performs analog-to-digital conversion on the transmitted electrical signal, and performs image processing, the processed image is output to the display screen, and the eyepiece optical system observes the image on the display screen.

[0026] Example 3 On the basis of Example 2, the first spherical lens 1 is made of optical glass H-ZF62, the second spherical lens 2 and the fifth spherical lens 5 are made of optical glass H-ZF88, the third spherical lens 3 is made of optical glass H-K9L, the fourth spherical lens 4 is made of optical glass H-LAF2, the sixth spherical lens 6 is made of optical glass H-ZLAF52A, and the first aspherical lens 7 is made of optical glass H-ZLAF68C. The relative aperture of the objective optical system is between 1:1.4 and 1:1.6, the total length of the objective optical system does not exceed 60mm, the focal length is not greater than 15mm, and the total weight is not greater than 45g; the horizontal field of view of the objective optical system is not less than 50°, the vertical field of view is not less than 35°, and the distortion within the overall field of view of the objective optical system is not greater than 5%; the imaging resolution of the objective optical system is not less than 800lp / mm, and the clear imaging range is 250mm~infinity; the working band of the objective optical system covers visible light~near infrared.

[0027] Example 4 The second aspherical lens 8 is made of optical glass H-LA52, the seventh spherical lens 9 is made of optical glass H-ZLAF68C, the eighth spherical lens 10 is made of optical glass H-ZF88, the exit pupil distance of the eyepiece optical system is not less than 15 mm, and the exit pupil diameter is not less than 4 mm; the focal length of the eyepiece optical system is not greater than 20 mm, the total length of the eyepiece optical system is not greater than 30 mm, the total weight is not greater than 50 g, the distortion within the overall field of view of the eyepiece optical system is not greater than 5%, and the working band of the eyepiece optical system covers visible to near-infrared.

[0028] Example 5 Based on Example 4, the objective optical system and the eyepiece optical system can be used alone or in combination.

[0029] Example 6 This embodiment provides a head-mounted optical system with a large field of view, such as Figure 1 As shown, it includes an objective optical system, a core module 11 and an eyepiece optical system, the shell of the objective optical system is detachably connected to the core module 11 and is located on one side of the core module 11, and the other side of the core module 11 is detachably connected to the shell of the eyepiece optical system; the objective optical system shell includes a first spherical lens 1, a second spherical lens 2, a third spherical lens 3, a fourth spherical lens 4, a double cemented lens and a first aspherical lens 7 which are arranged in sequence from the object side to the image side along the optical axis direction, wherein the double cemented lens includes a fifth spherical lens 5 and a sixth spherical lens 6, the fifth spherical lens 5 is close to the fourth spherical lens 4, the first spherical lens 1 is a concave-convex lens, the second spherical lens 2, the third spherical lens 3, the fourth spherical lens 4, the fifth spherical lens and the sixth spherical lens are all convex lenses, and the first aspherical lens 7 is a plano-convex lens. The eyepiece optical system housing includes a second aspherical lens 8, a seventh spherical lens 9 and an eighth spherical lens 10, which are arranged in sequence from the eye point side to the object side along the optical axis direction, wherein the second aspherical lens 8 is a plano-convex lens, the seventh spherical lens 9 is a concave-convex lens, and the eighth spherical lens 10 is a convex lens; The movement module 11 includes a shell, in which a sensor, a processing board and a display screen are arranged. The sensor is used to receive external light collected by the objective lens and convert it into an electrical signal. The processing board converts the transmitted electrical signal into an analog-to-digital signal and performs image processing. The processed image is output to the display screen, and the eyepiece observes the image on the display screen.

[0030] The lens material information of the eyepiece optical system and the objective optical system is shown in Table 1. The eyepiece optical system has an exit pupil diameter of 4.5 mm, an exit pupil distance of 20 mm, a total length of 25 mm, and a total weight of 49 g; the objective optical system has a relative aperture of 1 / 1.4, a horizontal field of view of 50°, a vertical field of view of 39°, a total length of 55 mm, and a total weight of 37 g.

[0031] Table 1 Optical material information of objective lens and eyepiece

[0032] like Figure 2-4 As shown in the figure, they are the distortion diagram, dispersion pattern diagram and optical transfer function diagram of the objective optical system. Figure 2 It can be seen that the objective optical system has negative distortion, and the distortion value of the entire field of view is no more than -3%; Figure 3 It can be seen that the diameter of the diffuse spot of the objective optical system is less than 0.013mm in both the on-axis field of view and the off-axis field of view, which has high resolution. Figure 4 It can be seen that when the optical transfer function (MTF) value of the objective optical system is 38.5 line pairs, the modulation frequency in the meridian and sagittal directions of the full field of view is greater than 50%.

[0033] like Figure 5-7 As shown in the figure, they are the distortion diagram, dispersion pattern diagram and optical transfer function diagram of the eyepiece optical system. Figure 5 It can be seen that the eyepiece optical system has positive distortion, and the distortion value of the entire field of view is less than 3%. Figure 6 It can be seen that the diameter of the diffuse spot of the eyepiece optical system is less than 0.025mm in both the on-axis field of view and the off-axis field of view, which has high resolution. Figure 7 It can be seen that when the optical transfer function (MTF) value of the eyepiece optical system is 70 line pairs, the modulation frequency in the meridian and sagittal directions of the full field of view is greater than 10%.

[0034] In summary, the large-field-of-view head-mounted optical system of the present invention is based on universal optical glass materials and can achieve a large-field-of-view observation range of more than 50° horizontal field of view and more than 35° vertical field of view through a combination optimization design of spherical lenses and aspherical lenses. The total length of the eyepiece and objective optical system is no more than 80 mm, and the total weight is no more than 90 g. This solves the problem of how to simultaneously meet the requirements of large field of view, high imaging quality, small size, and light weight, and can be widely used in the field of night vision equipment or head-mounted optical systems.

Claims

1. A head-mounted optical system with a large field of view, characterized in that: It comprises an objective optical system, a core module (11) and an eyepiece optical system, wherein the objective optical system is detachably connected to the core module (11) and is located on one side of the core module, and the other side of the core module (11) is detachably connected to the eyepiece optical system; The objective optical system comprises a first spherical lens (1), a second spherical lens (2), a third spherical lens (3), a fourth spherical lens (4), a doublet lens and a first aspherical lens (7) which are arranged in sequence from the object side to the image side along the optical axis; The eyepiece optical system comprises a second aspheric lens (8), a seventh spherical lens (9) and an eighth spherical lens (10), wherein the second aspheric lens (8), the seventh spherical lens (9) and the eighth spherical lens (10) are arranged in sequence from the eye point side to the object side along the optical axis direction.

2. The large field of view head-mounted optical system according to claim 1, characterized in that: The first spherical lens (1) and the seventh spherical lens (9) are both concave-convex lenses, the second spherical lens (2), the third spherical lens (3), the fourth spherical lens (4) and the eighth spherical lens (10) are all convex lenses, and the first aspherical lens (7) and the second aspherical lens (8) are both plano-convex lenses.

3. The large field of view head-mounted optical system according to claim 2, characterized in that: The doublet lens comprises a fifth spherical lens (5) and a sixth spherical lens (6); the fifth spherical lens (5) is close to the fourth spherical lens (4); and both the fifth spherical lens (5) and the sixth spherical lens (6) are convex lenses.

4. The large field of view head-mounted optical system according to claim 3, characterized in that: The first spherical lens (1) is made of optical glass H-ZF62, the second spherical lens (2) and the fifth spherical lens (5) are made of optical glass H-ZF88, the third spherical lens (3) is made of optical glass H-K9L, the fourth spherical lens (4) is made of optical glass H-LAF2, the sixth spherical lens (6) is made of optical glass H-ZLAF52A, and the first aspherical lens (7) is made of optical glass H-ZLAF68C.

5. The large field of view head-mounted optical system according to claim 1, characterized in that: The relative aperture of the objective optical system is between 1:1.4 and 1:1.6, the total length of the objective optical system does not exceed 60 mm, the focal length does not exceed 15 mm, and the total weight does not exceed 45 g; The horizontal field of view of the objective optical system is not less than 50°, the vertical field of view is not less than 35°, and the distortion within the overall field of view of the objective optical system is not greater than 5%; The imaging resolution of the objective optical system is not less than 800lp / mm, and the clear imaging range is 250mm~infinity; The working wavelength band of the objective optical system covers visible light to near infrared.

6. The large field of view head-mounted optical system according to claim 1, characterized in that: The second aspherical lens (8) is made of optical glass H-LA52, the seventh spherical lens (9) is made of optical glass H-ZLAF68C, and the eighth spherical lens (10) is made of optical glass H-ZF88.

7. The large field of view head-mounted optical system according to claim 1, characterized in that: The eyepiece optical system has an exit pupil distance of not less than 15 mm and an exit pupil diameter of not less than 4 mm; the focal length of the eyepiece optical system is not greater than 20 mm, the total length of the eyepiece optical system is not greater than 30 mm, and the total weight is not greater than 50 g; The distortion within the overall field of view of the eyepiece optical system is no more than 5%; The working band of the eyepiece optical system covers visible to near infrared.

8. The large field of view head-mounted optical system according to claim 1, characterized in that: The objective optical system and the eyepiece optical system may be used alone or in combination.

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