A relay lens for spectral imaging

Abstract

The invention discloses a relay lens for spectral imaging, comprising a front relay lens group and a rear relay lens group, wherein the front relay lens group is used to receive the image output by the imaging lens, and output the image to the filter device by light beam arrangement, and the rear relay lens group is used to receive the light beam output by the filter device, and image the light beam on the photosensitive device again. The invention ingeniously designs the specific lens combination of the front relay lens group and the rear relay lens group, and under the synergistic effect of each lens of the front relay lens group and the rear relay lens group, the relay lens group can achieve a large aperture and a large field of view, with a designed aperture of F2.8, an imaging range diameter of nearly 20mm, and a very short length, including a long space of 60mm in the middle of only about 180mm, and a resolution of up to 4 million pixels, which well meets the requirements of spectral imaging, and has a simple structure, a short length, and a light weight, and is suitable for the design of a high-definition compact relay lens with a large aperture and a large field of view.

Description

Technical Field

[0001] The invention relates to the field of optical technology, and in particular to a relay lens for spectral imaging. Background Art

[0002] In spectral imaging systems, a spectral filter is usually used to split light to achieve images of different spectral shooting targets. Adding a filter in the imaging light path often requires adding a set of relay lenses after the imaging lens to extend the light path and meet the filter's requirements for the incident aperture angle, while transmitting the image of the imaging lens to the photosensitive device.

[0003] Existing relay lenses are generally complex in structure, large in size and weight, which makes the total length of the system relatively long and the equipment bulky, especially portable equipment is very inconvenient to use. The imaging surface is not large enough, and the imaging quality does not meet the requirements of high-resolution systems. There is an urgent need for the design of a compact and high-quality relay lens system. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a high-definition compact relay mirror design which is simple in structure, short in length and suitable for large aperture and large field of view.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A relay lens for spectral imaging comprises a front relay lens group and a rear relay lens group. The front relay lens group is used to receive the image output by the imaging lens, arrange the light beam to meet the requirements of the filter for the light beam, and output it to the filter device. The rear relay lens group is used to receive the light beam output by the filter device and image the light beam on the photosensitive device again.

[0007] The front relay lens group includes a first double-cemented lens, a first single lens, and a second single lens, which are located on the same optical axis and are arranged in sequence; the first double-cemented lens is a cemented piece of a double concave lens and a double convex lens, and the double concave lens is used to receive the image light beam output by the imaging lens; the first single lens is a double concave negative lens; and the second single lens is a double convex positive lens;

[0008] The rear relay lens assembly comprises a front lens assembly part and a rear lens assembly part which are arranged in sequence and are both located on the same optical axis as the front relay lens assembly;

[0009] The front lens group part includes a third single lens and a second double cemented lens arranged in sequence; the third single lens is a double convex positive lens; the second double cemented lens is a cemented piece of a double concave lens and a double convex lens, and the light beam output by the third single lens is projected into the double concave lens;

[0010] The rear mirror group includes a fourth single lens, a fifth single lens and a sixth single lens arranged in sequence; the fourth single lens is a double convex positive lens; the fifth single lens is a meniscus positive lens with the convex surface facing the fourth single lens; the sixth single lens is a quasi-plano-concave negative lens with the quasi-plane facing the fifth single lens.

[0011] The first doublet is used for achromatism and higher-order aberrations of the field of view.

[0012] The first single lens is used to eliminate image curvature and coma.

[0013] The second single lens is used to achieve the focal length of the front group of the relay lens and to lower the exit height of the light. The second single lens is combined with the first double-cemented lens to enable the image output by the imaging lens to be imaged at infinity, and to achieve an air gap of 60 mm in the middle and an angle between the main light and the optical axis of less than 7.5 degrees.

[0014] The second doublet is used to ameliorate chromatic aberration and higher-order aberrations of the field of view.

[0015] The fourth single lens is used to reduce the length of the relay lens.

[0016] The fifth single lens is used to correct distortion and change the position of the image-side principal plane of the entire relay lens.

[0017] The sixth single lens is used to control the rear working distance of the entire relay lens and achieve a 1x magnification ratio.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention ingeniously designs the specific lens combination of the front relay lens group and the rear relay lens group. Under the synergistic effect of the lenses of the front relay lens group and the rear relay lens group, the relay lens group can achieve a large aperture and a large field of view. The designed aperture is F2.8, the imaging range diameter is nearly 20 mm, and the length is controlled to be very short, including the long space of 60 mm in the middle is only about 180 mm, and the resolution is as high as 4 million pixels, which well meets the requirements of spectral imaging. In addition, the structure is simple, the length is short, and the weight is light, so it is suitable for the design of a high-definition compact relay lens with a large aperture and a large field of view. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a relay lens for spectral imaging provided by an embodiment of the present invention;

[0021] In the figure: 1, first double glued lens; 2, first single lens; 3, second single lens; 4, third single lens; 5, second double glued lens; 6, fourth single lens; 7, fifth single lens; 8, sixth single lens; 11, biconcave lens; 12, biconvex lens; 51, biconcave lens; 52, biconvex lens; 100, filter device. DETAILED DESCRIPTION

[0022] The content of the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0023] Example:

[0024] like Figure 1 As shown, the relay lens for spectral imaging provided in this embodiment is divided into a front relay lens group and a rear relay lens group, wherein the front relay lens group is used to receive the image output by the imaging lens (i.e., the image plane of the objective lens), and to make it meet the requirements of the filter for the light beam through light beam arrangement, and output it to the filter device 100, and the rear relay lens group receives the light beam output by the filter device, and images the light beam on the photosensitive device again. Specifically, the front relay lens group images the image (Y'1) of the objective lens at infinity (Y'2), and at the same time realizes the space interval of 60mm in the middle and the maximum angle between the main light and the optical axis is less than 7.5 degrees; the rear relay lens group then images the intermediate image (Y'2) at infinity on the SENSOR plane (Y'3) of the camera, and makes the system meet the performance requirement of 1x magnification.

[0025] Specifically, the front relay lens group includes a first double-cemented lens 1, a first single lens 2, and a second single lens 3, which are located on the same optical axis and arranged in sequence. The first double-cemented lens 1 is a cemented piece of a double concave lens 11 and a double convex lens 12. The image beam (i.e., the image plane of the object image) output by the imaging lens is projected into the double concave lens 11. In the entire relay lens, the main function of the first double-cemented lens 1 is to eliminate chromatic aberration and higher-order aberrations of the field of view (high-order aberrations refer to aberrations of a higher order than primary aberrations). The first single lens 2 is a double concave negative lens, and its main function is to eliminate image curvature (field curvature) and coma. The second single lens 3 is a double convex positive lens, which is mainly used to achieve the focal length of the front group and lower the exit height of the light. It is combined with the first double-cemented lens 1 to make the image of the front objective lens at infinity, and to achieve an air interval of 60 mm in the middle and an angle between the main light and the optical axis of less than 7.5 degrees.

[0026] The rear relay lens group includes a front lens group part and a rear lens group part which are arranged in sequence and are both located on the same optical axis as the front relay lens group. The front lens group part includes a third single lens 4 and a second double cemented lens 5 which are arranged in sequence; the third single lens 4 is a double convex positive lens, which is mainly used to achieve optical performance in the entire relay lens; the second double cemented lens 5 is a cemented part of a double concave lens 51 and a double convex lens 52, which is mainly suitable for achromatism and high-order aberrations of field of view.

[0027] The rear lens group includes a fourth single lens 6, a fifth single lens 7 and a sixth single lens 8 which are arranged in sequence. The fourth single lens 5 is a double convex positive lens, which is made of a material with a high refractive index and high dispersion. Its main function is to reduce the length of the entire relay lens and achieve the main focal length performance of the relay lens. The fifth single lens 7 is a meniscus positive lens with a convex surface facing the fourth single lens 6. Its main function is to correct distortion and change the position of the image-side principal plane of the entire relay lens; the sixth single lens 8 is a quasi-plano-concave negative lens with a quasi-plane facing the fifth single lens 7. Its main function is to control the rear working distance of the entire relay lens and achieve a magnification of one times the image, wherein the quasi-plane refers to the surface of the surface close to a plane.

[0028] The present application ingeniously designs the specific lens combination of the front relay lens group and the rear relay lens group. Under the synergistic effect of the various lenses of the front relay lens group and the rear relay lens group, the relay lens group can achieve a large aperture and a large field of view. The designed aperture is F2.8, the imaging range diameter is nearly 20mm, and the length is controlled to be very short, including the long space of 60mm in the middle is only about 180mm. The resolution is as high as 4 million pixels, which well meets the requirements of spectral imaging. In addition, the structure is simple, the length is short, and the weight is light, which is suitable for the design of high-definition compact relay lenses with large aperture and large field of view.

[0029] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention.

Claims

1. A relay lens for spectral imaging, comprising a front relay lens group and a rear relay lens group, wherein the front relay lens group is used to receive the image output by the imaging lens, arrange the light beam to meet the requirements of the filter for the light beam, and output it to the filter device, and the rear relay lens group is used to receive the light beam output by the filter device and image the light beam on the photosensitive device again, characterized in that: The front relay lens group includes a first double-cemented lens, a first single lens, and a second single lens, which are located on the same optical axis and are arranged in sequence; the first double-cemented lens is a cemented piece of a double concave lens and a double convex lens, and the double concave lens is used to receive the image light beam output by the imaging lens; the first single lens is a double concave negative lens; and the second single lens is a double convex positive lens; The rear relay lens assembly comprises a front lens assembly part and a rear lens assembly part which are arranged in sequence and are both located on the same optical axis as the front relay lens assembly; The front lens group part includes a third single lens and a second double cemented lens arranged in sequence; the third single lens is a double convex positive lens; the second double cemented lens is a cemented piece of a double concave lens and a double convex lens, and the light beam output by the third single lens is projected into the double concave lens; The rear lens assembly comprises a fourth single lens, a fifth single lens and a sixth single lens arranged in sequence; the fourth single lens is a double convex positive lens; the fifth single lens is a meniscus positive lens with the convex surface facing the fourth single lens; the sixth single lens is a quasi-plano-concave negative lens with the quasi-plane facing the fifth single lens; The first doublet is used for achromatism and higher-order aberrations of the field of view; The first single lens is used to eliminate image curvature and coma; The second single lens is used to achieve the focal length of the front relay lens group and lower the exit height of the light. The second single lens is combined with the first double-cemented lens to enable the image output by the imaging lens to be imaged at infinity, and to achieve an air gap of 60 mm in the middle and an angle between the main light and the optical axis of less than 7.5 degrees.

2. The relay lens for spectral imaging according to claim 1, characterized in that: The second doublet is used to ameliorate chromatic aberration and higher-order aberrations of the field of view.

3. The relay lens for spectral imaging according to claim 1, characterized in that: The fourth single lens is used to reduce the length of the relay lens.

4. The relay lens for spectral imaging according to claim 1, characterized in that: The fifth single lens is used to correct distortion and change the position of the image-side principal plane of the entire relay lens.

5. The relay lens for spectral imaging according to claim 1, characterized in that: The sixth single lens is used to control the rear working distance of the entire relay lens and achieve a 1x magnification ratio.

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