Automatic focusing endoscope bayonet lens optical assembly
By designing the automatic focus endoscope bayonet lens optical component composed of six spherical lenses, the inconvenience of manually adjusting focus in traditional endoscope bayonet lenses is solved, and wide spectrum imaging and hyperoptics are achieved in the visible light to the near-infrared band. Performance, simplifies operation and improves image clarity.
Patent Information
- Application Number
- CN202411338465.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2024-12-31
AI Technical Summary
Traditional endoscopic bayonet lenses require doctors to manually adjust the focus knob, which is inconvenient to operate, affecting image clarity and diagnostic effectiveness.
Design an automatic focus endoscope mount lens optical assembly composed of six spherical lenses, which can achieve wide spectrum imaging in the visible to near infrared band and achieve high optical performance at both the proximal and distal ends of the focus distance. A specific lens combination and power relationship enable autofocus.
The autofocus function is realized, simplifies operation, improves image clarity and diagnostic effectiveness, ensuring high-quality imaging at different object distances.
Smart Images
Figure CN119224989A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an optical lens system, and more particularly to an auto-focus endoscope bayonet lens optical assembly. Background Art
[0002] As an indispensable part of minimally invasive surgery, endoscope is a modern medical device integrating "examination-diagnosis-treatment". The endoscope bayonet lens is the main component that connects the hard lens at the front end of the endoscope with the back end display system. Its function is to transmit the image information collected by the front end hard lens to the back end photosensitive chip and display it through the display for medical staff to observe. Therefore, the imaging quality of the endoscope bayonet lens is very important, which affects the image clarity of the entire endoscope system and the effectiveness of clinical diagnosis.
[0003] In actual clinical use, for photographing lesions at different object distances, traditional endoscope bayonet lenses often require doctors to manually adjust the adapter focus knob, which brings inconvenience to doctors during surgery. Therefore, the autofocus endoscope bayonet lens can achieve one-button focus, which can effectively solve the above problem. Summary of the invention
[0004] In view of the above technical problems, the present invention proposes an autofocus endoscope bayonet lens optical assembly, which can achieve wide-spectrum imaging in the visible light to near-infrared band and achieve high optical performance at both the near and far ends of the focusing distance.
[0005] The invention is composed of only six spherical lenses, and has the advantages of simple structure and easy implementation. The invention provides a simple solution for the auto-focus endoscope bayonet lens.
[0006] The present invention specifically relates to an auto-focus endoscope bayonet lens optical assembly, which comprises: a first lens with positive focal power and a convex surface facing the object surface, a second lens with negative focal power and a concave surface facing the image surface, a doublet lens with positive focal power composed of a third lens and a fourth lens, a fifth lens with negative focal power and a concave surface facing the image surface, and a sixth lens with positive focal power and a convex surface facing the image surface, which are arranged in sequence along the optical axis from the object side. The focal power of the first lens is φ1, and the second lens is φ2. The optical focal length of the lens assembly is φ2, the optical focal length of the doublet lens composed of the third lens and the fourth lens is φ34, the optical focal length of the fifth lens is φ5, the optical focal length of the sixth lens is φ6, and the optical focal length of the entire lens assembly is φ, which satisfies the following relationship: 0.037≤φ≤0.029; wherein the total optical length of the lens assembly, i.e., TTL<35mm, and the optical focal length φ1 of the first lens and the optical focal length φ of the entire lens assembly satisfy the following relationship: 2.11≤φ1 / φ≤2.69.
[0007] Furthermore, the focal power φ2 of the second lens and the focal power φ of the entire lens assembly satisfy the following relationship: -3.76≤φ2 / φ≤-2.95.
[0008] Furthermore, the focal length φ34 of the doublet lens composed of the third lens and the fourth lens and the focal length φ of the entire lens assembly satisfy the following relationship: 2.74≤φ34 / φ≤3.48.
[0009] Furthermore, the optical power φ5 of the fifth lens and the optical power φ of the entire lens assembly satisfy the following relationship: -3.93≤φ5 / φ≤-3.08.
[0010] Furthermore, the focal power φ6 of the sixth lens and the focal power φ of the entire lens assembly satisfy the following relationship: 1.38≤φ6 / φ≤1.76.
[0011] Furthermore, the refractive index of the third lens is n3, and the refractive index of the fourth lens is n4, satisfying the following relationship: 0<|n4-n3|<0.18.
[0012] Furthermore, the Abbe number of the third lens is Vd3, and the Abbe number of the fourth lens is Vd4, satisfying the following relationship: 10<|Vd4-Vd3|<30.
[0013] Further, when the lens assembly focuses on an object at an infinite distance, the spatial distance from the first lens to the sixth lens to the window is set to D1, and when the system focuses on an object at an object distance of 150 mm, the spatial distance from the first lens to the sixth lens to the window is set to D2, and the following conditions are met: <D2 / D1<1.5。
[0014] In addition, the present invention also relates to an endoscope system, which includes the above-mentioned auto-focus endoscope bayonet lens optical component.
[0015] The present invention proposes an auto-focus endoscope bayonet lens optical assembly, which consists of only six spherical lenses, can achieve wide-spectrum imaging in the visible light to near-infrared band, and achieve high optical performance at both the near and far ends of the focusing distance. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The drawings described herein are used to provide a further understanding of the present disclosure and constitute a part of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure. In the drawings: Figure 1 It is a structural schematic diagram of the auto-focus endoscope bayonet lens of the present invention when the object distance is infinite; Figure 2 It is a schematic structural diagram of the auto-focus endoscope bayonet lens of the present invention when the focusing object distance is 150 mm; Figure 3 It is a curve diagram of the modulation transfer function of the auto-focus endoscope bayonet lens of the present invention when the focusing object is at an infinite distance; Figure 4 It is a curve diagram of the modulation transfer function of the auto-focus endoscope bayonet lens of the present invention when the focusing object distance is 150 mm. DETAILED DESCRIPTION
[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.
[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0019] In the following description, the shape (convex or concave) of the surface of a lens element is defined as viewed from the corresponding side (ie, viewed from the object side or from the image side).
[0020] In the embodiment disclosed in the present invention, in order from the object side to the image side, the auto-focus endoscope bayonet lens optical assembly includes: a first lens 101 with positive optical power and a convex surface facing the object plane, a second lens 102 with negative optical power and a concave surface facing the image plane, a doublet lens with positive optical power composed of a third lens 103 and a fourth lens 104, a fifth lens 105 with negative optical power and a concave surface facing the image plane, and a sixth lens 106 with positive optical power and a convex surface facing the image plane.
[0021] In one embodiment, Figure 1 and Figure 2 As shown, in the embodiment given in the present invention, the first lens 101 is a plano-concave lens element with negative optical power and a concave surface facing the image plane; the second lens 102 is a meniscus lens element with negative optical power and a concave surface facing the image plane; the third lens 103 is a biconvex lens element with positive optical power.
[0022] The third lens 103 is a plastic lens element having a convex object side surface 104a and a convex image side surface 104b and having positive power, and the fourth lens 104 is a plastic lens element having a concave object side surface 105a and a convex image side surface 105b and having negative power. The third lens and the fourth lens form a doublet lens with positive power. The design of the doublet lens with positive power composed of positive and negative power lens elements with different Abbe numbers helps to eliminate chromatic aberration of the entire optical system.
[0023] Furthermore, an image sensor (not shown) is arranged at the image plane for imaging.
[0024] In the specific embodiment disclosed in the present invention, the optical focal length of the first lens is φ1, the optical focal length of the second lens is φ2, the optical focal length of the doublet lens composed of the third lens and the fourth lens is φ34, the optical focal length of the fifth lens is φ5, the optical focal length of the sixth lens is φ6, and the optical focal length of the entire lens assembly is φ, and φ satisfies the following relationship: 0.037≤φ≤0.029.
[0025] The total optical length TTL of the lens assembly is defined as the distance between the object-side surface of the first lens element on the optical axis and the image sensor (ie, the image plane). In all embodiments disclosed in the present invention, the total optical length TTL of the lens assembly is less than 35 mm.
[0026] In one embodiment, the focal power φ1 of the first lens and the focal power φ of the entire lens assembly satisfy the following relationship: 2.11≤φ1 / φ≤2.69. The above lens focal power setting helps to ensure that the lens assembly can produce clear images in the 400nm-900nm multi-spectral range.
[0027] In one embodiment, the focal power φ2 of the second lens and the focal power φ of the entire lens assembly satisfy the following relationship: -3.76≤φ2 / φ≤-2.95.
[0028] In one embodiment, the focal power φ34 of the doublet lens composed of the third lens and the fourth lens and the focal power φ of the entire lens assembly satisfy the following relationship: 2.74≤φ34 / φ≤3.48.
[0029] In one embodiment, the optical power φ5 of the fifth lens and the optical power φ of the entire lens assembly satisfy the following relationship: -3.93≤φ5 / φ≤-3.08.
[0030] In one embodiment, the focal power φ6 of the sixth lens and the focal power φ of the entire lens assembly satisfy the following relationship: 1.38≤φ6 / φ≤1.76.
[0031] Through the preferred implementation of the above lens optical power, it can be further ensured that the lens assembly can produce clear images in the multi-spectral range of 400nm-900nm.
[0032] In one embodiment, the refractive index of the third lens is n3, and the refractive index of the fourth lens is n4, satisfying the following relationship: 0<|n4-n3|<0.18.
[0033] In one embodiment, the Abbe number of the third lens is Vd3, and the Abbe number of the fourth lens is Vd4, satisfying the following relationship: 10<|Vd4-Vd3|<30.
[0034] In one embodiment, when the lens assembly focuses on an object at an infinite distance, the spatial distance from the first lens to the sixth lens to the window is set to D1, and when the system focuses on an object at an object distance of 150 mm, the spatial distance from the first lens to the sixth lens to the window is set to D2, and the following conditions are met: <D2 / D1<1.5。
[0035] In the present invention, all lens element surfaces are aspherical. Detailed optical data of each lens element in a specific embodiment are given in Table 1, where the units of the radius of curvature (r), the thickness of the lens element and / or the distance between elements along the optical axis and the diameter are all expressed in mm. "Nd" is the refractive index, and "Vd" is the Abbe number.
[0036] In Table 1, the distances between various elements (and / or surfaces) are labeled "Lmn" (where m refers to the lens element number, n=1 refers to the element thickness, and n=2 refers to the air gap to the next lens element), and are measured on the optical axis z. Each number is measured from the previous surface.
[0037] Specifically, the first lens 101 has a first surface and a second surface along the optical axis from the object side (not shown in the figure), the second lens 102 has a first surface and a second surface along the optical axis from the object side (not shown in the figure), the third lens 103 has a first surface and a second surface along the optical axis from the object side (not shown in the figure), the fourth lens 104 has a first surface and a second surface along the optical axis from the object side (not shown in the figure), the fifth lens 105 has a first surface and a second surface along the optical axis from the object side (not shown in the figure), and the sixth lens 106 has a first surface and a second surface along the optical axis from the object side (not shown in the figure).
[0038] As shown in Table 1, a first distance L11 from a first surface of the first lens 101 to a second surface of the first lens 101 is 2.5 mm, that is, a thickness of the first lens element 101 is 2.5 mm; an air gap L12 between the second surface of the first lens 101 and the first surface of the second lens is 0.6 mm, that is, a distance from the first lens element 101 to the second lens element 102 is 0.6 mm; a distance L21 between the first surface of the second lens and the second surface of the second lens is 3.9 mm, that is, a thickness of the second lens element 102 is 3.9 mm, and so on.
[0039] Table 1
[0040] In a preferred embodiment, the distance (1.2 mm) between the doublet lens formed by the third lens and the fourth lens and the fifth lens 105 (the air gap between the surface 104 b and the surface 105 a ) is less than one twentieth of TTL (35 mm) (1.2<1.75 mm).
[0041] Furthermore, the distance between the third lens 103 and the sixth lens 106 (i.e., the distance between the surface 103a and the surface 106b) is less than one quarter of TTL (35mm) (8.6mm<8.75mm). The above distance setting helps to ensure that the lens assembly can produce clear images in the 400nm-900nm multi-spectral range.
[0042] Figure 3 The figure shows a curve diagram of the modulation transfer function of the auto-focus endoscope bayonet lens of the present invention when the focusing object is at infinity. Figure 4 The figure shows a schematic diagram of the modulation transfer function curve of the auto-focus endoscope bayonet lens of the present invention when the focus object distance is 150 mm. The black solid line at the top of the figure and close to the straight line represents the diffraction limit, which is the theoretical maximum resolution capability of the lens assembly. The other curves are schematic diagrams of the modulation transfer function curves of the variable-power endoscope lens of the present invention at multiple field angles. It can be seen that the curves of these modulation transfer functions are all close to the diffraction limit, and the closer to the diffraction limit, the higher the resolution capability of the lens. It can be seen from the figure that the auto-focus endoscope bayonet lens optical assembly proposed by the present invention has excellent resolution capability whether the focus object distance is infinite (i.e., the far end) or the focus object distance is 150 mm (i.e., the near end).
[0043] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.
Claims
1. An auto-focus endoscope bayonet lens optical assembly, characterized in that: include: Arranged in sequence along the optical axis from the object side are a first lens with positive refractive power and a convex surface facing the object plane, a second lens with negative refractive power and a concave surface facing the image plane, a doublet lens with positive refractive power consisting of a third lens and a fourth lens, a fifth lens with negative refractive power and a concave surface facing the image plane, and a sixth lens with positive refractive power and a convex surface facing the image plane; The focal power of the first lens is φ1, the focal power of the second lens is φ2, the focal power of the doublet lens composed of the third lens and the fourth lens is φ34, the focal power of the fifth lens is φ5, the focal power of the sixth lens is φ6, and the focal power of the entire lens assembly is φ, which satisfies the following relationship: 0.037≤φ≤0.029; The total optical length of the lens assembly, ie, TTL < 35 mm, and the focal length φ1 of the first lens and the focal length φ of the entire lens assembly satisfy the following relationship: 2.11≤φ1 / φ≤2.
69.
2. The auto-focus endoscope bayonet lens optical assembly according to claim 1, characterized in that: The optical power φ2 of the second lens and the optical power φ of the entire lens assembly satisfy the following relationship: -3.76≤φ2 / φ≤-2.
95.
3. The auto-focus endoscope bayonet lens optical assembly according to claim 1, characterized in that: The focal power φ34 of the doublet lens composed of the third lens and the fourth lens and the focal power φ of the entire lens assembly satisfy the following relationship: 2.74≤φ34 / φ≤3.
48.
4. The auto-focus endoscope bayonet lens optical assembly according to claim 1, characterized in that: The optical power φ5 of the fifth lens and the optical power φ of the entire lens assembly satisfy the following relationship: -3.93≤φ5 / φ≤-3.
08.
5. The auto-focus endoscope bayonet lens optical assembly according to claim 1, characterized in that: The focal power φ6 of the sixth lens and the focal power φ of the entire lens assembly satisfy the following relationship: 1.38≤φ6 / φ≤1.
76.
6. The auto-focus endoscope bayonet lens optical assembly according to any one of claims 1 to 5, characterized in that: The refractive index of the third lens is n3, and the refractive index of the fourth lens is n4, satisfying the following relationship: 0<|n4-n3|<0.
18.
7. The auto-focus endoscope bayonet lens optical assembly according to any one of claims 1 to 5, characterized in that: The Abbe number of the third lens is Vd3, and the Abbe number of the fourth lens is Vd4, which satisfy the following relationship: 10<|Vd4-Vd3|<30.
8. The auto-focus endoscope bayonet lens optical assembly according to any one of claims 1 to 5, characterized in that: When the lens assembly focuses on an object at an infinite distance, the spatial distance from the first lens to the sixth lens to the window is set to D1. When the system focuses on an object at an object distance of 150 mm, the spatial distance from the first lens to the sixth lens to the window is set to D2, and the following conditions are met: <D2 / D1<1.5。 9. An endoscope system, characterized in that: include: An autofocus endoscope bayonet lens optical assembly as claimed in any one of claims 1 to 8.