A secondary optical magnification and image relay system for stereo fluorescence endoscope based on dual optical path design

Abstract

The present invention relates to a stereoscopic fluorescence endoscope secondary optical magnification and image relay system based on a dual optical path design. The optical system increases the optical axis spacing of a conventional dual optical path laparoscope from 4-5mm to more than 10mm through a secondary image relay magnification design, and ensures that the image quality is not lost while magnifying the image surface. The relay system includes a first-stage image relay magnification group, a steering prism group, and a second-stage image relay magnification group. For any optical path system, the endoscope imaging optical system divides the imaging light channel into a visible light channel and a near-infrared fluorescence channel. This system can increase the optical axis spacing of the existing dual optical path laparoscope to a reasonable size through the design of a secondary optical magnification and image relay system, so as to solve the problem that the existing camera system is too large and cannot realize the synchronous camera of the dual optical path laparoscope.

Description

Technical Field

[0001] The invention relates to the technical field of optical design, and in particular to a secondary optical magnification and image relay system of a stereoscopic fluorescence endoscope based on a dual-light path design. Background Art

[0002] Nowadays, minimally invasive surgery has become an important development direction in all fields of surgical medicine. For patients, minimally invasive surgery has the characteristics of less damage and fast postoperative recovery, and any minimally invasive surgery cannot be carried out without the help of endoscopes. Endoscopes have the characteristics of both diagnosis and treatment, which caters to the medical development direction of early diagnosis and low-traumatic treatment, and is one of the key development areas of medical devices. There are some problems with existing endoscopes (especially domestic endoscopes): such as low image clarity, which affects early diagnosis capabilities; low optical magnification, small field of view angle, etc. These problems limit the early diagnosis capabilities of endoscopes, and often force doctors to perform more biopsies on patient tissues to make up for their shortcomings. Therefore, the development of 4K ultra-clear endoscopes is currently a major development direction for medical endoscopes.

[0003] For endoscopes, fluoroscopes (working spectrum of 400-900nm) have a wider working spectrum than traditional white light endoscopes (working spectrum of 400-700nm), and the near-infrared band has stronger penetration ability, which can provide images of human surface tissues and fluorescent angiography of tissues below the surface, such as blood vessel development, while white light endoscopes mainly show images of the surface of human tissues. Therefore, fluoroscopes have been widely used in clinical practice.

[0004] During the operation, if the operation is performed only through the 2D plane image captured by a single-channel endoscope, the doctor lacks an intuitive three-dimensional sense of the surgical environment, which limits the doctor's operating ability, increases the workload of the operation, and reduces the accuracy of the operation. According to the needs of doctors, stereo endoscopes can provide doctors with three-dimensional images, which can provide doctors with more accurate patient information and avoid doctors' misoperation.

[0005] Current clinical needs hope that endoscopes can provide clearer (4K) and more three-dimensional (3D) images. However, as far as current endoscope products are concerned, there are corresponding products on the market for separate 4K ultra-clear endoscopes, separate 3D endoscopes, and fluorescent endoscopes. However, among the endoscope products on the market that meet the ultra-clear image function of 4K, none of them can achieve the requirements of stereoscopic imaging and can only provide 2D white light or fluorescent images; endoscopes that meet the requirements of stereoscopic imaging are limited by their resolution and have clarity problems. This means that doctors can only choose between clarity and stereoscopic images during clinical procedures. How to combine stereoscopic imaging with 4K is a major problem facing the current development of endoscopes. Therefore, it is very important to develop a set of fluorescent endoscopes that can achieve both 4K imaging and stereoscopic imaging.

[0006] However, in actual use, the diameter of the endoscope barrel itself is limited. Generally, the front end diameter of the endoscope is limited to within 10 mm. Under this condition, the size of the imaging surface obtained by the stereo dual-optical path system is limited and cannot meet the space requirements for placing the CMOS required for 4K imaging. How to solve this problem is the key to achieving the fusion of 4K and stereo imaging. Summary of the invention

[0007] In view of the above-mentioned prior art and existing problems, the present invention proposes a secondary optical magnification and image relay system of a stereoscopic fluorescence endoscope optical system based on a dual optical path design. The optical system is connected with the dual optical path channel, and the relay optical system includes: a first-stage image magnification group, a steering prism group, and a second-stage image magnification group.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] The present invention discloses a stereoscopic fluorescence endoscope optical system based on a dual-light path design, which includes a left optical system and a right optical system symmetrically arranged along the central axis of the mirror tube. The left and right optical systems both include an objective lens imaging unit (including an imaging objective lens group and a rotating lens group in sequence), a first-stage rotating image magnifying group, a turning prism group, a second-stage rotating image magnifying group, and an eyepiece imaging unit (which may include an imaging eyepiece group, a coupling lens group, and an imaging element group in sequence) from the object side to the imaging side. The displacement parallax when the human eye observes an object is simulated by adjusting the parallel spacing.

[0010] The imaging objective lens group is used to capture the scene.

[0011] The image transfer lens group is a symmetrical structure with an imaging magnification ratio of 1:1. The image captured by the imaging objective lens group is transmitted over a long distance, and at the same time, the image aberration is corrected together with the imaging objective lens group to obtain better image quality.

[0012] The image relay magnification group in the present invention is a two-stage magnification group. The first-stage image relay magnification group is placed in the lens barrel together with the 1:1 image relay lens group, and is located in front of the steering prism group; the second-stage image relay magnification group is placed after the steering prism group, and is located in the same lens barrel as the eyepiece imaging unit. The two-stage magnification method can effectively avoid the problem of the front-end endoscope diameter being too large while ensuring that the image plane size meets the imaging requirements. For an endoscopic laparoscope, the front end diameter is generally limited to less than 10 mm. In the case of a dual optical path, the maximum diameter of a single optical path cannot exceed 5 mm. In this case, it is unrealistic to achieve 4K-level image quality because the image plane is too small and the size of the CMOS / CCD is limited, which cannot meet the requirements of 4K imaging. In order to meet the 4K image quality, the enlargement of the image plane is essential, and in order to meet the diameter requirements of the front end, it is designed as a two-stage magnification system. The first-stage image relay magnification group is connected to the image relay lens group at the objective end and is located in the same lens barrel, and is used to magnify the output image once and transmit it through the steering prism group arranged outside the lens barrel; the second-stage image relay magnification group is connected to the imaging eyepiece and is located in the same lens barrel, and performs secondary magnification on the first-stage relay magnified image while completing aberration correction.

[0013] Furthermore, the first-stage image relay magnification group includes a first double-cemented positive lens, a second double-cemented positive lens, a third double-cemented negative lens, and a fourth double-cemented positive lens in sequence. The diameter of the first-stage image relay magnification group in the direction perpendicular to the optical axis does not exceed 4.8mm, and the first relay half-image height is within 1.5-2mm, ensuring that the aperture of the subsequent single-channel optical system is no more than 15mm. The second-stage image relay magnification group will magnify the first relay image to the required image height, and the half-image height is generally within 2-3mm; the distance between the second-stage image relay magnification group and the first-stage image relay magnification group in the direction of the optical axis should be no less than 25mm.

[0014] The steering prism group is located between the first-stage image-relaying and magnifying group and the second-stage image-relaying and magnifying group. It increases the distance between the optical axes of the two optical channels of the stereo endoscope through two reflections (three rhombic prisms can be used to achieve two 90-degree turns of the two optical axes through surface reflection to achieve separation of the optical axes of the dual-channel optical paths), thereby meeting the spatial layout requirements of the subsequent lens group and the two CMOS / CCDs.

[0015] The imaging eyepiece group forms an image at infinity after image transfer and amplification, so as to facilitate the coordinated completion of imaging with the subsequent coupling lens group.

[0016] The coupling lens group images the infinite image obtained through the eyepiece on the CMOS / CCD image sensor, and the image size can also be adjusted by zooming. A beam splitter is set in front of the CMOS / CCD to image the light on the CMOS / CCD used for white light and the CCD / CMOS used for fluorescence.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The stereoscopic fluorescence endoscope optical system based on dual optical path design can achieve 4K imaging and stereoscopic imaging through a unique secondary image magnification and steering relay system. The combination of 4K ultra-clear images and stereoscopic images can greatly enhance doctors' ability to examine patients and the accuracy of surgical operations.

[0019] 2. The present invention, through a unique secondary image magnification and steering relay system, increases the spacing of the optical axes of the stereoscopic dual-channel optical path while meeting the needs of 4K imaging and stereoscopic imaging (the optical axis spacing of a conventional dual-optical path laparoscope can be increased from 4-5mm to more than 10mm, and the image quality is not lost while the image surface is magnified), provides space for setting a spectroscopic element, and can simultaneously realize fluorescence imaging and white light imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 is a schematic diagram of the structure of an optical system according to an embodiment of the present invention;

[0022] Figure 2 It is a structural schematic diagram of an image-reversing magnifying objective lens and a turning prism assembly of an optical system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to specific embodiments and accompanying drawings.

[0024] Figure 1 The overall structure diagram of the stereoscopic fluorescence endoscope optical system based on the dual optical path design of the present invention is shown. The optical system of the present invention is composed of two optical systems arranged at intervals, independent of each other, with the same structure and symmetrically placed. Each optical system is composed of an imaging objective lens 1, a 1:1 image transfer lens group 2, a first-stage image transfer magnification group 3-1, a steering prism group 3-2, a second-stage image transfer magnification group 3-3, an imaging eyepiece group 4, a variable coupling lens group and a spectroscopic imaging CMOS group 5 in order from the object side to the image side along the optical axis.

[0025] In the embodiment of the present invention, the imaging objective lens 1 is placed at the front end of the optical system, followed by a 1:1 image transfer lens group 2. The image transfer lens group 2 can adjust the image quality of the captured image without changing the size of the image captured by the imaging objective lens 1. The imaging objective lens is a common 75° field of view endoscope objective lens. The 1:1 image transfer lens group performs aberration correction while transmitting the image obtained by the objective lens.

[0026] The image relay magnification group is placed behind the 1:1 image relay system, and is used for performing secondary magnification on the relay image transmitted by the image relay system, including a first-stage image relay magnification group and a second-stage image relay magnification group. The first-stage image relay magnification group is connected with the image relay lens group at the objective end and is located in the same lens barrel, and is used for performing primary magnification on the transmitted image, and transmitting it through the steering prism group arranged outside the lens barrel; the second-stage image relay magnification group is connected with the imaging eyepiece group, and is located in the same lens barrel, and performs secondary magnification on the first-stage relay magnified image while completing aberration correction.

[0027] Figure 2 Table 1 is a schematic diagram of the image-relay magnifying group and the steering lens group. Table 1 is the lens parameters of the image-relay magnifying group. The first-stage image-relay magnifying group includes, in sequence, the first double-cemented positive lens, i.e., lenses 3-1-1 and 3-1-2 in the figure, the second double-cemented positive lens, i.e., lenses 3-2-1 and 3-2-2 in the figure, the third double-cemented negative lens, i.e., lenses 3-3-1 and 3-3-2 in the figure, and the fourth double-cemented positive lens, i.e., lenses 3-4-1 and 3-4-2 in the figure. The second-stage image-relay magnifying group includes, in sequence, the seventh double-cemented positive lens, i.e., lenses 3-7-1 and 3-7-2 in the figure, the eighth double-cemented positive lens, i.e., lenses 3-8-1 and 3-8-2 in the figure, the ninth double-cemented negative lens, i.e., lenses 3-9-1 and 3-9-2 in the figure, and the tenth double-cemented positive lens, i.e., lenses 3-10-1 and 3-10-2 in the figure. S94-S105 are mirrors corresponding to the first-stage image-relay magnifying lens group, and S109-S120 are mirrors corresponding to the second-stage image-relay magnifying lens group. Since the first-stage image-relay magnifying lens group is placed in the same lens barrel as the imaging objective lens group and the image-relay lens group, the radius of the lens used is limited to no more than 4.8mm. The size of the obtained first-stage magnified relay image needs to be controlled to avoid the lens being too large, and the first-stage relay half-image height is controlled within 1.5-2mm to ensure that the aperture of the subsequent single-channel optical system is no more than 15mm. However, in order to obtain a larger image surface, it is necessary to perform a secondary magnification on the first-stage magnified relay image so that the half-image height is generally within 2-3mm after the secondary magnification; when performing optical design, a longer distance is reserved between S105 and S109, which is not less than 25mm. It is used to simulate the optical axis distance of light propagation when placing a total reflection steering prism, and at the same time ensure that there is enough space to place the steering prism. The middle turning prism group can use three rhombic prisms 3-5 and 3-6 to reflect the 90° turning optical axis. After two reflections, each optical path is emitted in a direction parallel to the optical axis of the image transmission element. And the optical axis interval of the subsequent double optical paths is increased, which is convenient for the installation of subsequent CMOS / CCD and other components.

[0028] Table 1 Parameters of image relay magnifying lens set

[0029]

[0030]

[0031] Note: S106~108 in the table are virtual surfaces, which actually correspond to the reflection surfaces where the image-relay prism is placed.

[0032] The imaging eyepiece is located behind the second-stage image-reversing magnifying lens group, and is used to image the image obtained by the image-reversing magnification at infinity to obtain parallel outgoing light. The angle of the obtained parallel light relative to the optical axis corresponds to the requirements of the subsequent coupling lens.

[0033] In addition, the system also includes a fiber optic lighting device, which can be installed using the conventional installation method of an ordinary rigid tube endoscope and is therefore not described in this patent.

[0034] In summary, the secondary optical magnification and image relay system of the stereoscopic fluorescence endoscope optical system based on the dual optical path design of the present invention realizes the combination of 4K imaging and stereoscopic imaging through the secondary magnification design when the endoscope diameter and space are limited, and can realize white light imaging and fluorescence imaging at the same time, greatly improving the doctor's ability to examine the patient and the accuracy of surgical operations.

[0035] The embodiments described above are only for illustrating the technical ideas and features of the present invention, and their purpose is to enable people skilled in the art to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the patent scope of the present invention. That is, all equivalent changes or modifications made according to the spirit disclosed by the present invention should still be included in the patent scope of the present invention.

Claims

1. A secondary optical magnification and image relay system of a stereoscopic fluorescence endoscope optical system based on a dual optical path design, characterized in that: The endoscope optical system is symmetrically provided with double optical paths along the central axis of the scope tube, and the relay system comprises from front to back: a first-stage image relay magnification group, a steering prism group, and a second-stage image relay magnification group, the first-stage image relay magnification group is connected with the objective lens imaging unit in the endoscope optical system and is arranged in the same scope, the second-stage image relay magnification group is connected with the eyepiece imaging unit in the endoscope optical system, and the steering prism group and the second-stage image relay magnification group are arranged outside the scope; The objective lens imaging unit includes an imaging objective lens group and a 1:1 image transfer lens group. The diameter of the first-stage image transfer magnification group in the direction perpendicular to the optical axis does not exceed 4.8 mm. The imaging objective lens group, the 1:1 image transfer lens group and the first-stage image transfer magnification group are placed in the same lens barrel, and the primary relay half image height is within 1.5-2 mm, ensuring that the aperture of the subsequent single-path optical system is no greater than 15 mm. The turning prism group is used to make two 90-degree turns of the dual light paths to achieve separation of the optical axes of the dual light paths; The second-stage image relay magnification group is placed in the same lens barrel as the imaging eyepiece, and is used to magnify the primary relay image to the required image height, with the half image height within 2~3mm; the second-stage image relay magnification group cooperates with the first-stage image relay magnification group to complete aberration correction; The distance between the second-stage image relay magnification group and the first-stage image relay magnification group in the direction of the optical axis is not less than 25 mm.

2. The secondary optical amplification and image relay system of the stereoscopic fluorescence endoscope optical system based on dual optical path design according to claim 1, characterized in that: The first-stage image relay and magnification group includes, in sequence, a first double-cemented positive lens, a second double-cemented positive lens, a third double-cemented negative lens, and a fourth double-cemented positive lens.

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