Optical imaging structure, imaging lens and endoscope
By setting up a spectroscopic prism and lens group in the optical imaging structure of the endoscope, the integration of lighting and imaging is achieved, solving the lens processing problem in the endoscope miniaturization design, and improving accuracy and stability.
Patent Information
- Application Number
- CN202420971817.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2034-04-30
AI Technical Summary
During the miniaturization design process of endoscopes, due to the structural constraints of the separation of imaging lenses and lighting lenses, the lens size is small, the processing accuracy, consistency and stability are difficult to guarantee, and the cost is high.
An optical imaging structure is designed, by providing a spectroscopic prism between the object side and the imaging side, the light introduced by the light guide fiber is reflected to the object side for illumination, and imaging is achieved through the first lens group and the second lens group without adding a separate illumination lens.
The integration of the lighting and imaging functions of the endoscope is achieved, reducing the number and size of the lenses, promoting the miniaturization of the endoscope, and improving the processing accuracy and stability of the lenses.
Smart Images
Figure CN222672047U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of optical equipment, and in particular to an optical imaging structure, an imaging lens and an endoscope. Background Art
[0002] An electronic flexible endoscope is a device that can be inserted into the human body for inspection or treatment. When working, an endoscope needs a light source to illuminate the inspection target. The main principle is to use optical fiber to guide the illumination light inside the light source to the front end of the scope, and then irradiate it onto the inspection target after passing through the illumination lens. Because the spatial distribution of the light intensity and the divergence angle of the light emitted by ordinary light-guiding optical fibers cannot be well adapted to the imaging field of view and inspection requirements of the endoscope, an illumination lens is required to shape the light emitted by the optical fiber.
[0003] However, since the structural dimensions of the insertion part of the endoscope are relatively small, the imaging lens and the lighting lens must be arranged at the same time, which makes the end of the endoscope lens very large. In order to meet the demand for miniaturization of endoscopes, it is necessary to process smaller lenses. However, the smaller the lens, the more difficult it is to ensure the processing accuracy, consistency and stability, and the processing cost will be higher, which is not conducive to the further development of endoscopes towards miniaturization. Utility Model Content
[0004] In view of this, the utility model provides an optical imaging structure, an imaging lens and an endoscope to solve the problem that the structure of the imaging lens and the illumination lens being separated restricts the miniaturization of the endoscope.
[0005] In a first aspect, the utility model provides an optical imaging structure for an endoscope, wherein the optical imaging structure has an object side and an imaging side arranged opposite to each other, and the optical imaging structure comprises:
[0006] Light-guiding optical fiber, used to introduce illumination light;
[0007] A first lens group, disposed on the object side, for illumination and imaging;
[0008] A second lens group, arranged on the imaging side, for imaging;
[0009] The beam splitter prism is arranged between the object side and the imaging side, and is used to reflect the light introduced by the light-guiding optical fiber to the object side, and transmit the imaging light focused by the first lens group to the second lens group.
[0010] Beneficial effects: A beam splitter prism is arranged between the object side and the imaging side of the optical imaging structure, a first lens group for lighting and imaging is arranged on the object side, and a second lens group for imaging is arranged on the imaging side. The beam splitter prism reflects the light introduced by the light-guiding optical fiber to the object side for lighting. After adopting this optical imaging structure, the illumination and imaging of the endoscope can be realized simultaneously without adding a separate lighting lens. Compared with the endoscope with a separate imaging lens and a lighting lens in the related art, it is conducive to realizing the miniaturization design of the endoscope.
[0011] In some embodiments, the first lens group includes:
[0012] An illumination lens, disposed adjacent to the beam splitter prism;
[0013] The front lens is spaced apart and arranged on a side of the illumination lens away from the beam splitter prism.
[0014] Beneficial effects: The illumination lens of the first lens group is mainly used to transmit the incident light entering from the light-guiding optical fiber, realize the illumination of the imaging structure, meet the imaging conditions, and realize the normal operation of the endoscope; and the lens is used as the transmission medium of the illumination light, the structure is simple and easy to implement.
[0015] In some embodiments, the absolute value of the curvature radius of the end surface of the illumination lens facing the front lens is greater than the absolute value of the curvature radius of the end surface of the front lens facing the illumination lens.
[0016] Beneficial effect: The absolute value of the curvature radius of the end face of the illumination lens facing the front lens is greater than the absolute value of the curvature radius of the end face of the front lens facing the illumination lens. This design can achieve a larger field of view angle and divergence angle during endoscopic observation, expand the area of the observation area, and obtain better observation clarity.
[0017] In some embodiments, the second lens group includes:
[0018] a rear lens, disposed adjacent to the beam splitter prism;
[0019] The cemented lens is spaced apart and arranged on a side of the rear lens away from the beam splitter prism.
[0020] Beneficial effect: After the stray light is removed and the resolution is improved through the aperture diaphragm on the beam splitter prism, the image is transmitted through the rear lens and the cemented lens and then received, identified and transmitted by the imaging sensor, with high reliability.
[0021] In some embodiments, a side of the rear lens close to the beam splitter prism is a plane.
[0022] Beneficial effect: The side of the rear lens close to the beam splitter prism is a plane, and compared with a curved surface, a plane design is more convenient for fixing and installation.
[0023] In some embodiments, a stop is disposed on a side of the beam splitter prism facing the imaging side.
[0024] Beneficial effect: The aperture is arranged on the side of the beam splitter prism facing the imaging side to ensure the imaging quality.
[0025] In some embodiments, a light guiding prism is further disposed between the light guiding optical fiber and the beam splitting prism.
[0026] Beneficial effect: Compared with the method in which the light of the light-guiding optical fiber directly enters the beam splitter prism, the light-guiding prism is added to guide the light beam for propagation, and the light-guiding optical fiber does not need to be bent, thereby avoiding the breakage of the light-guiding optical fiber and achieving better reliability.
[0027] In some embodiments, the first lens group includes an illumination lens and a front lens, and the second lens group includes a rear lens and a cemented lens; the front lens, the illumination lens, the beam splitter prism, the rear lens and the cemented lens are arranged in sequence along the axial direction of the optical imaging structure; a light guiding prism is also provided between the light guiding optical fiber and the beam splitter prism.
[0028] Beneficial effects: By adopting the above-mentioned optical imaging structure, the layout of each lens is reasonable and the structure is compact, and illumination and imaging are achieved simultaneously. After adopting this optical imaging structure, the endoscope can further realize miniaturization design; in addition, a light-guiding prism is used to guide light, which avoids the bending of the light-guiding optical fiber and has high reliability.
[0029] In a second aspect, the utility model further provides an imaging lens, comprising an imaging sensor and any one of the above-mentioned optical imaging structures.
[0030] Beneficial effect: Due to the adoption of the optical imaging structure of the utility model, the imaging lens has the same technical effect as the optical imaging structure, which will not be described in detail here.
[0031] In a third aspect, the utility model also provides an endoscope, comprising the above-mentioned imaging lens.
[0032] Beneficial effect: The imaging lens of the endoscope adopts the optical imaging structure of the utility model, and there is no need to set up a separate lighting lens. The imaging lens has both imaging and lighting functions, and one lens has two uses. The endoscope is easy to realize miniaturized design and the structure is more compact. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0034] Figure 1 This is a layout diagram of the optical imaging structure of an embodiment of the utility model, in which the light propagation direction is given;
[0035] Figure 2 for Figure 1 A schematic diagram of the position of the light-guiding surface of each lens in the optical imaging structure;
[0036] Figure 3 A field curvature diagram of an imaging lens according to an embodiment of the utility model;
[0037] Figure 4 A distortion diagram of the imaging lens of an embodiment of the utility model;
[0038] Figure 5 A vertical axis chromatic aberration diagram of the imaging lens of an embodiment of the utility model;
[0039] Figure 6 This is the MTF diagram of the imaging lens of the embodiment of the utility model at a working distance of 3mm;
[0040] Figure 7 This is the MTF diagram of the imaging lens of the embodiment of the utility model at a working distance of 100 mm;
[0041] Figure 8 is a light distribution curve diagram of the illumination structure of the imaging lens of an embodiment of the utility model;
[0042] Fig. 9 It is a light schematic diagram of the illumination structure of the imaging lens of an embodiment of the utility model.
[0043] Description of reference numerals:
[0044] 1. Front lens; 2. Illumination lens; 3. Beam splitter prism; 4. Rear lens; 5. Cemented lens; 6. Protective glass; 7. Imaging sensor; 8. Aperture; 9. Light guide prism; 10. Light guide fiber;
[0045] 100, first lens group; 200, second lens group. DETAILED DESCRIPTION
[0046] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.
[0047] In the description of the utility model, it should be noted that, unless otherwise specified, "multiple" means two or more; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the utility model. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0048] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.
[0049] Combine the following Figures 1 to 9 , describing an embodiment of the utility model.
[0050] According to an embodiment of the present utility model, on the one hand, an optical imaging structure for an endoscope is provided, the optical imaging structure having an object side and an imaging side arranged opposite to each other, and the optical imaging structure comprises:
[0051] Light-guiding optical fiber 10, used to introduce illumination light;
[0052] A first lens group 100 is disposed on the object side and is used for illumination and imaging;
[0053] A second lens group 200 is disposed on the imaging side and is used for imaging;
[0054] The beam splitter prism 3 is disposed between the object side and the imaging side, and is used to reflect the light introduced by the light-guiding optical fiber 10 to the object side, and transmit the imaging light focused by the first lens group 100 to the second lens group 200 .
[0055] A beam splitter prism 3 is arranged between the object side and the imaging side of the optical imaging structure, a first lens group 100 for illumination and imaging is arranged on the object side, and a second lens group 200 for imaging is arranged on the imaging side. The beam splitter prism 3 reflects the light introduced by the light guide optical fiber 10 to the object side for illumination. After using the optical imaging structure, the illumination and imaging of the endoscope can be realized simultaneously without adding a separate illumination lens, which is conducive to realizing the miniaturization design of the endoscope compared with the existing endoscope with separate imaging lens and illumination lens.
[0056] In some embodiments, first lens group 100 includes:
[0057] An illumination lens 2 is arranged adjacent to the beam splitter prism 3;
[0058] The front lens 1 is spaced apart and arranged on a side of the illumination lens 2 away from the beam splitter prism 3 .
[0059] The illumination lens 2 of the first lens group 100 is mainly used to transmit the incident light entering from the light-guiding optical fiber 10 to realize the illumination of the imaging structure, meet the imaging conditions, and realize the normal operation of the endoscope; and the lens is used as the transmission medium of the illumination light, which has a simple structure and is easy to implement.
[0060] In some embodiments, the absolute value of the curvature radius of the illumination lens 2 close to the front lens 1 is greater than the absolute value of the curvature radius of the front lens 1 close to the illumination lens 2 .
[0061] The absolute value of the curvature radius of the illumination lens 2 on the side close to the front lens 1 is greater than the absolute value of the curvature radius of the front lens 1 on the side close to the illumination lens 2. This design can achieve a larger field of view angle and divergence angle during endoscopic observation, expand the area of the observation area, and obtain better observation clarity.
[0062] In some embodiments, second lens group 200 includes:
[0063] A rear lens 4 is arranged adjacent to the beam splitter prism 3;
[0064] The cemented lens 5 is spaced apart and arranged on a side of the rear lens 4 away from the beam splitter prism 3 .
[0065] In addition, a stop 8 is provided on the side of the dichroic prism 3 facing the imaging side. The stop 8 is an aperture stop. The aperture stop is provided on the side of the dichroic prism 3 facing the second lens group 200 .
[0066] After the stray light is removed and the resolution is improved by the aperture stop on the beam splitter prism 3, the light is then transmitted through the rear lens 4 and the cemented lens 5 for imaging and then received, identified and transmitted by the imaging sensor 7, with high reliability. The cemented lens 5 is adopted, and the structure is compact while the light propagation path is controlled. The aperture stop is provided on the side of the beam splitter prism 3 facing the second lens group 200, which ensures the imaging quality while also making the structure relatively compact.
[0067] In some embodiments, a side of the rear lens 4 close to the beam splitter prism 3 is a plane.
[0068] The side of the rear lens 4 close to the beam splitter prism 3 is a flat surface. Compared with a curved surface, a flat surface design is more convenient for fixing and installation.
[0069] In some embodiments, a light guiding prism 9 is further disposed between the light guiding optical fiber 10 and the beam splitting prism 3 .
[0070] Compared with the method in which the light from the light-guiding optical fiber 10 directly enters the beam splitter prism 3, the light-guiding prism 9 is added to guide the light beam for propagation, and the light-guiding optical fiber 10 does not need to be bent, thereby avoiding the breakage of the light-guiding optical fiber 10 and improving reliability.
[0071] It should be noted that the lighting light source is conducted by the light-guiding optical fiber 10 and deflected by the light-guiding prism 9, which avoids the high heat generated by directly using LED light to burn the head end or cause harm to the human body, and also prevents leakage problems caused by front-end rupture.
[0072] In some embodiments, Figure 1 As shown, the optical imaging structure for endoscope includes a light-guiding optical fiber 10, a beam splitter prism 3 located in the light propagation path of the light-guiding optical fiber 10, a first lens group 100 located on the object side, and a second lens group 200 located on the imaging side; it is used to reflect the light introduced by the light-guiding optical fiber 10 to the object side, and transmit the imaging light focused by the first lens group 100 to the second lens group 200. The first lens group 100 includes an illumination lens 2 and a front lens 1, and the second lens group 200 includes a rear lens 4 and a cemented lens 5; the front lens 1, the illumination lens 2, the beam splitter prism 3, the rear lens 4 and the cemented lens 5 are arranged in sequence along the axial direction of the optical imaging structure; a light-guiding prism 9 is also arranged between the light-guiding optical fiber 10 and the beam splitter prism 3.
[0073] By adopting the above-mentioned optical imaging structure, the layout of each lens is reasonable and the structure is compact, and illumination and imaging are achieved simultaneously. After adopting this optical imaging structure, the endoscope can further achieve miniaturized design; in addition, the light-guiding prism 9 is used for light guidance, which avoids the bending of the light-guiding optical fiber 10 and has high reliability.
[0074] like Figure 2As shown, if the light transmission surfaces are numbered from left to right along the axial direction of the optical imaging structure (surface a to surface n), the specific parameters are shown in the following table:
[0075] Face number Radius of curvature interval Nd Vd a 10 0.3 2 25.4 b 0.55 0.322 c -1.992 0.456 1.95 17.9 d -1.147 0.02 e(Prism) ∞ 0.8 1.52 64.2 f(aperture) ∞ 0.02 g ∞ 0.616 1.44 94.5 h -0.557 0.02 i 0.959 0.659 1.52 58.6 j -0.6 0.3 2 25.4 k ∞ 0.586 l ∞ 0.1 1.52 64.2 m ∞ 0.01 n ∞
[0076] Other various data:
[0077] The field of view of 2W is 150°, the illumination divergence angle is 150°, and the FNO (F number) is 7.
[0078] According to an embodiment of the present utility model, on the other hand, an imaging lens is provided, comprising an imaging sensor 7 and an optical imaging structure.
[0079] The imaging lens combines the functions of the imaging lens and the lighting lens in the related technology, which further reduces the size of the optical system, makes it possible to miniaturize the endoscope in a compact space, and also provides more operability. Since the space of the lighting lens is saved, the lens size can be increased accordingly, which improves the processing accuracy, consistency and stability of the lens.
[0080] A protective glass 6 is also provided on the receiving side of the imaging sensor 7 to protect the imaging sensor 7 .
[0081] like Figure 3-Figure 5 As shown in Figure 2, at a 150° field of view, the optical imaging structure corrects the off-axis aberration well, and each aberration is small. Figure 6 and Figure 7 It can be seen that the MTF of 3mm close-up and 100mm distant view is not much different (MTF indicates the minimum detail size that the optical system can transmit under a certain contrast), achieving a larger depth of field. Figure 8 It can be seen from the light distribution curve that the imaging lens of the present invention adopts a unique lighting structure layout. The lighting structure composed of a light-guiding optical fiber 10, a light-guiding prism 9, a beam splitter prism 3, an illumination lens 2 and a front lens 1 achieves a larger illumination divergence angle. For example, the illumination divergence angle can reach 150° when the light intensity is 15%.
[0082] According to an embodiment of the present utility model, on another aspect, an endoscope is provided, comprising the above-mentioned imaging lens.
[0083] The imaging lens of the endoscope adopts the optical imaging structure of the utility model, and there is no need to set up a separate lighting lens. The imaging lens has both imaging and lighting functions, and one lens has two uses. The endoscope is easy to realize miniaturized design and has a more compact structure.
[0084] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.
Claims
1. An optical imaging structure for an endoscope, characterized in that: The optical imaging structure has an object side and an imaging side arranged opposite to each other, and the optical imaging structure comprises: A light-guiding optical fiber (10) for introducing illumination light; A first lens group (100), arranged on the object side, for illumination and imaging; A second lens group (200), arranged on the imaging side, for imaging; The beam splitter prism (3) is arranged between the object side and the imaging side, and is used to reflect the light introduced by the light-guiding optical fiber (10) to the object side, and transmit the imaging light focused by the first lens group (100) to the second lens group (200).
2. The optical imaging structure according to claim 1, characterized in that: The first lens group (100) comprises: An illumination lens (2) is arranged adjacent to the beam splitter prism (3); The front lens (1) is arranged at a distance from the illumination lens (2) on a side away from the beam splitter prism (3).
3. The optical imaging structure according to claim 2, characterized in that: The absolute value of the curvature radius of the end surface of the illumination lens (2) facing the front lens (1) is greater than the absolute value of the curvature radius of the end surface of the front lens (1) facing the illumination lens (2).
4. The optical imaging structure according to claim 1, characterized in that: The second lens group (200) comprises: A rear lens (4) is arranged adjacent to the beam splitting prism (3); A cemented lens (5) is arranged at a distance on a side of the rear lens (4) away from the beam splitting prism (3).
5. The optical imaging structure according to claim 4, characterized in that: The side of the rear lens (4) close to the beam splitting prism (3) is a plane.
6. The optical imaging structure according to claim 1, characterized in that: A diaphragm (8) is provided on the side of the beam splitter prism (3) facing the imaging side.
7. The optical imaging structure according to any one of claims 1 to 6, characterized in that: A light guiding prism (9) is also provided between the light guiding optical fiber (10) and the light splitting prism (3).
8. The optical imaging structure according to claim 1, characterized in that: The first lens group (100) comprises an illumination lens (2) and a front lens (1), and the second lens group (200) comprises a rear lens (4) and a cemented lens (5); the front lens (1), the illumination lens (2), the beam splitter prism (3), the rear lens (4) and the cemented lens (5) are arranged in sequence along the axial direction of the optical imaging structure; and a light guiding prism (9) is also provided between the light guiding optical fiber (10) and the beam splitter prism (3).
9. An imaging lens, characterized in that: It comprises an imaging sensor (7) and the optical imaging structure according to any one of claims 1 to 8.
10. An endoscope, characterized in that: The imaging lens according to claim 9 is included.