CN213023749U

CN213023749U - Endoscope adapter optical system of internal focusing

Info

Publication number: CN213023749U
Application number: CN202022249543.0U
Authority: CN
Inventors: 辜长明
Original assignee: Zibo Haitai Xinguang Optical Technology Co ltd
Current assignee: Zibo Haitai Xinguang Optical Technology Co ltd
Priority date: 2020-10-12
Filing date: 2020-10-12
Publication date: 2021-04-20
Anticipated expiration: 2030-10-12

Abstract

The utility model relates to an endoscope adapter optical system of interior focusing, belong to the technical field of wicresoft's medical treatment, utilize the design philosophy of zoom system, reduce the amount of focus movement, when guaranteeing that the imaging quality of whole focusing range approaches diffraction limit, can also make endoscope adapter optical system's combined focal length basically unchangeable, it is more accurate to have the focusing, and can realize advantages such as can see near infrared broadband formation of image, suitable be applied to in the endoscope adapter optical system of ultra-high definition, shorten the amount of focus movement, reach the purpose of accurate focusing.

Description

Endoscope adapter optical system of internal focusing

Technical Field

The invention relates to an endoscope adapter optical system with internal focusing, and belongs to the technical field of minimally invasive medical treatment.

Background

The endoscope adapter is connected with the endoscope and the image pickup part, the endoscope adapter is used for imaging a virtual image of an eyepiece of the endoscope onto the image pickup chip and displaying the image on a screen through the image pickup system, and the distance of the virtual image formed by the eyepiece of the endoscope is generally between-100 mm and infinity, so that the focusing range of the endoscope adapter is required to meet the range between 100mm and infinity.

The focusing mode of the endoscope adapter mainly adopts the mode of whole group focusing, namely the focusing ring drives the lens group to move back and forth together to achieve the purpose of focusing. The main disadvantage of this focusing approach is that the adapter optical lens cannot have good imaging quality over such a large focusing range. In addition, as the imaging system gradually develops towards the direction of 4K ultra high definition, the number of pixels is more and more, and the effective imaging size of the corresponding image sensor is also more and more, so that the focal length of the optical lens of the adapter is required to be larger, the distance that the lens needs to move for imaging focusing within the range from 100mm to infinity is also larger, for example, the focal length of the adapter with the focal length of 20mm is less than 4mm, and the focal length of the adapter with the focal length of 30mm is required to be larger than 6mm, that is, the focusing ring needs to move at least 6mm within the range of nearly 360 degrees in rotation, so that the focusing precision is reduced, the doctor often cannot focus to the clearest image position in the operation process, and the operation of the.

Therefore, it is urgent to overcome the above problems by using a new focusing method, and the endoscope adapter optical system with internal focusing according to the present disclosure is an effective solution to the problems.

Disclosure of Invention

The present disclosure provides an endoscope adapter optical system with internal focusing, which utilizes the design concept of a zoom system to reduce the amount of focusing movement and improve the accuracy of focusing. The combined focal length of the optical system of the endoscope adapter is basically unchanged while the imaging quality of the whole focusing range is ensured to approach the diffraction limit.

The technical solution of the present disclosure will now be described in detail with reference to the accompanying drawings:

an endoscope adapter optical system with internal focusing, the value of focal length f is in the range of 20mm to 40mm, and comprises an aperture diaphragm 1, a front fixed group 2, a focusing group 3, a rear fixed group 4, an imaging surface 5, the aperture diaphragm 1 is an entrance pupil of the adapter optical system, the diameter of the entrance pupil is more than 3mm, and is coincident with the exit pupil position of the endoscope optical system, the front fixed group 2 is a meniscus negative lens formed by a double convex positive lens and a double concave negative lens, the focusing group 3 is a triple cemented positive lens formed by two double convex positive lenses and a double concave negative lens, the double concave negative lens is positioned between the two double convex positive lenses, the rear fixed group 4 comprises a negative lens 41 and a double cemented lens 42, the negative lens 41 is a double concave lens, the double cemented lens 42 is a double convex positive lens formed by a double convex positive lens and a meniscus negative lens, the negative lens 41 is in front, the double cemented lens 42 is in rear, and a fixed air gap is arranged between the negative lens 41 and the double cemented lens 42, the imaging surface 5 is the focusing surface of the adapter optical system, that is, the target surface of the image sensor, the aperture diaphragm 1, the front fixed group 2, the focusing group 3, the rear fixed group 4, the imaging surface 5 is coaxially arranged in sequence, the optical system is characterized in that the aperture diaphragm 1, the front fixed group 2, the rear fixed group 4, the imaging surface 5 is fixed in position, the focusing group 3 is changeable in position between the front fixed group 2 and the rear fixed group 4, different positions correspond to focusing positions at different object distances, when the object distance is changed from infinity to 100mm, the focusing group 3 moves along the optical axis in the direction of the front fixed group 2, and the moving distance L is less than 3 mm.

The technical scheme of the disclosure is further technically characterized in that the imaging waveband range of the internal focusing endoscope adapter optical system covers visible light and near infrared and is between 400nm and 900 nm.

The technical scheme of the present disclosure is further technically characterized in that the imaging quality of the endoscope adapter optical system of the inner focusing is kept consistent during the focusing process, and the value of the transfer function (MTF) for the maximum exit field angle ± 7.5 ° of the endoscope is greater than 30% at 100 pairs/mm.

The technical scheme of the disclosure is further technically characterized in that the focal length of the endoscope adapter optical system with internal focusing is basically kept unchanged in the focusing process, and the variation is less than or equal to 1%.

The advantages of the present disclosure are:

1. focusing under different object distances is realized by utilizing an internal focusing mode, the moving distance of a focusing group is shortened, and the focusing is more accurate.

2. The focal length and the imaging quality can be kept consistent in the whole focusing range, and the wide-spectrum imaging from visible light to near infrared can be realized.

Drawings

FIG. 1: the endoscope adapter optics system of the present disclosure is schematically focused.

FIG. 2: the optical path diagram of embodiment one when the object distance is at infinity.

FIG. 3: the optical path diagram of the first embodiment when the object distance is 100 mm.

FIG. 4: the schematic diagram of the movement distance L of the focusing group 3 in the first embodiment.

Detailed Description

The first embodiment is as follows: this embodiment has a structure identical to that described in the disclosure, and only the key data is listed to avoid duplication. An endoscope adapter optical system with internal focusing, a focal length f =30mm, an entrance pupil diameter 3.5mm, an imaging band range 400nm-900nm, when an object distance changes from infinity to 100mm, a distance L =2mm that a focusing group 3 moves in a direction of an optical axis toward a front fixed group 2, when the object distance is infinity, the focal length f =30mm, when the object distance is 100mm, the focal length is 30.3mm, a focal length change amount is 1%, and a minimum value of MTF of a full field of view within a field angle + -7.5 ° is 35% at 100 pairs of lines/mm.

The working principle is as follows: the front fixed group 2, the focusing group 3 and the negative lens 41 form a negative-positive-negative optical structure, when the object distance changes from infinity to 100mm, the angle of the chief ray emitted from the negative lens 41 in the full field of view can be controlled to remain unchanged by adjusting the position of the positive lens, that is, the imaging distance is ensured to remain unchanged, the incident height of the chief ray on the double-cemented lens 42 can also be controlled to remain unchanged, that is, the image height is controlled to remain unchanged, that is, the focal length is also controlled to change only slightly, and the amount of focal length change in this embodiment is 1%. Meanwhile, the negative-positive-negative optical structure can effectively shorten the moving distance required by positive group focusing, and the moving distance is controlled to be 1.75mm in the embodiment. The full field MTF value is close to the diffraction limit in the range of imaging wave band 400nm-900nm, and the method can be realized through proper optical material selection and optical path optimization design.

The technical scheme disclosed by the invention is suitable for being applied to an optical system of an ultra-high-definition endoscope adapter, the focusing movement amount is shortened, and the purpose of accurate focusing is achieved.

Claims

1. An endoscope adapter optical system with internal focusing, the range of the focal length f is between 20mm and 40mm, the endoscope adapter optical system comprises an aperture diaphragm (1), a front fixing group (2), a focusing group (3), a rear fixing group (4), an imaging surface (5), the aperture diaphragm (1) is an entrance pupil of the adapter optical system, the diameter of the entrance pupil is larger than 3mm and is coincided with the exit pupil position of the endoscope optical system, the front fixing group (2) is a meniscus negative lens formed by gluing a biconvex positive lens and a biconcave negative lens, the focusing group (3) is a tri-glued positive lens formed by gluing two biconvex positive lenses and a biconcave negative lens, the biconcave negative lens is positioned between the two biconvex positive lenses, the rear fixing group (4) comprises a negative lens (41) and a biconcave lens (42), the negative lens (41) is a biconcave lens, and the biconcave lens (42) is a biconvex positive lens formed by gluing the biconvex positive lens and the biconvex negative lens, the negative lens (41) is arranged in front, the double-cemented lens (42) is arranged in back, a fixed air gap is arranged between the negative lens (41) and the double-cemented lens (42), the imaging surface (5) is the focusing surface of the optical system of the adapter, namely the target surface of the image sensor, the aperture diaphragm (1), the front fixing group (2), the focusing group (3), the back fixing group (4) and the imaging surface (5) are coaxially arranged in sequence, it is characterized in that the aperture diaphragm (1), the front fixed group (2), the rear fixed group (4), the imaging surface (5) are fixed, the focusing group (3) is changeable between the front fixed group (2) and the rear fixed group (4), different positions correspond to focusing positions under different object distances, when the object distance is changed from infinity to 100mm, the focusing group (3) moves along the direction of the optical axis forward fixing group (2), and the moving distance L is less than 3 mm.

2. The internally focused endoscope adapter optical system according to claim 1, wherein the imaging band range of said internally focused endoscope adapter optical system covers visible and near infrared, between 400nm-900 nm.

3. An internally focused endoscope adapter optical system according to claim 1 or 2, characterized in that the imaging quality of the internally focused endoscope adapter optical system is kept consistent during focusing, and the value of the transfer function (MTF) for the endoscope maximum exit field angle ± 7.5 ° is more than 30% at 100 lines/mm.

4. An internally focused endoscope adapter optical system according to claim 1 or 2, characterized in that the focus of the internally focused endoscope adapter optical system remains substantially unchanged during focusing, with a variation of less than or equal to 1%.

5. An internally focusing endoscope adapter optical system according to claim 1 or 2, characterized in that the adapter optical system focal length f =30mm, the entrance pupil diameter 3.5mm, the imaging band range 400nm-900nm, the focusing group (3) is moved in the direction of the optical axis forward fixed group (2) by a distance L =1.75mm when the object distance is changed from infinity to 100mm, the focal length f =30mm when the object distance is infinity, the focal length f =30.3mm when the object distance is 100mm, the focal length variation is 1%, and the MTF value of the full field of view within the field angle ± 7.5 ° is 35% at the minimum value at 100 lines/mm.