All-glass endoscope

Abstract

An all-glass endoscope is characterized by sequentially comprising a first lens (L1) which is a negative lens, a second lens (L2) which is a positive lens, a third lens (L3) which is a positive lens, a fourth lens (L4) which is a positive lens, a fifth lens (L5) which is a negative lens, a sixth lens (L6) which is a positive lens, a seventh lens (L7) which is a negative lens and an optical filter (IR). Wherein the first lens (L1) and the second lens (L2) form a first lens group (E1), the fourth lens (L4) and the fifth lens (L5) form a second lens group (E2), the sixth lens (L6) and the seventh lens (L7) form a third lens group (E3), and an optical filter (IR) is arranged; f1 / F is greater than or equal to-0.9 and less than or equal to 0; 1.59 < = F2 / F < = 3.5; -8 < = F3 / F < =-6; 0.5 < = f / F < = 2.5; the all-glass endoscope has the advantages of stable optical performance, small size, wide visual field, high imaging quality and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical imaging, and more specifically, relates to a fully glass endoscope.

Background Art

[0002] In recent years, endoscope lens technology has developed rapidly in the directions of high resolution, miniaturization, and multi-functional integration. In traditional endoscopes, plastic or hybrid material lenses are mostly used, and their materials are prone to heat deformation, aging, etc., which extremely affects the imaging quality. Due to the stable optical performance and strong corrosion resistance of fully glass endoscopes, they have gradually become a research hotspot in the fields of high-end medical treatment and industrial inspection. To make up for the shortcomings of traditional endoscopes, a fully glass endoscope will be further described herein.

Summary of the Invention

[0003] Aiming at the problems existing in the prior art, the present invention provides a fully glass endoscope, aiming to make up for the shortcomings of traditional endoscopes such as being prone to heat deformation and low imaging quality, and realizing characteristics such as stable optical performance, large field of view, and clear imaging.

[0004] The present invention is realized through the following technical solutions:

[0005] A fully glass endoscope, characterized in that it successively includes a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), a seventh lens (L7), and a filter (IR), consisting of a total of 8 lenses; wherein, the first lens (L1) and the second lens (L2) form a first lens group (E1), the fourth lens (L4) and the fifth lens (L5) form a second lens group (E2), and the sixth lens (L6) and the seventh lens (L7) form a third lens group (E3);

[0006] The first lens (L1) is made of glass material and has a negative optical power. Its object side is convex and its image side is concave;

[0007] The second lens (L2) is made of glass material and has a positive optical power. Its object side is convex and its image side is concave;

[0008] The third lens (L3) is made of glass material and has a positive optical power. Its object side is convex and its image side is convex;

[0009] The fourth lens (L4) is made of glass material and has a positive optical power. Its object side is convex and its image side is convex;

[0010] The fifth lens (L5) is made of glass material and has a negative optical power. Its object side is concave and its image side is convex;

[0011] The sixth lens (L6) is made of glass and has a positive optical power. Its object side is convex and its image side is convex;

[0012] The seventh lens (L7) is made of glass and has a negative optical power. Its object side is concave and its image side is convex;

[0013] This all-glass endoscope satisfies the following conditional expressions:

[0014] -0.9 ≤ F1 / F ≤ 0;

[0015] 1.59 ≤ F2 / F ≤ 3.5;

[0016] -8 ≤ F3 / F ≤ -6;

[0017] 0.5 ≤ f / F ≤ 2.5;

[0018] Where F1, F2, F3, f, and F are the effective focal lengths of the first lens group (E1), the second lens group (E2), the third lens group (E3), the third lens (L3), and the entire all-glass endoscope lens, respectively.

[0019] Preferably, the following relational expressions are satisfied:

[0020] 0.2 ≤ ΣT1 / TTL ≤ 0.5;

[0021] 0.1 ≤ ΣT2 / TTL ≤ 0.35;

[0022] 0.15 ≤ ΣT3 / TTL ≤ 0.3;

[0023] Where ΣT1 is the on-axis distance from the object side of the first lens (L1) to the image side of the second lens (L2), ΣT2 is the on-axis distance from the object side of the fourth lens (L4) to the image side of the fifth lens (L5), ΣT3 is the on-axis distance from the object side of the sixth lens (L6) to the image side of the seventh lens (L7), and TTL is the on-axis distance from the object side of the first lens of this all-glass endoscope to the imaging surface.

[0024] Preferably, the following relational expressions are satisfied:

[0025] 140° ≤ FOV ≤ 145°;

[0026] 3.5 ≤ FNO ≤ 4.5;

[0027] Where FOV is the maximum field of view angle of the entire all-glass endoscope lens, and FNO is the F-number of the entire all-glass endoscope lens.

[0028] Preferably, the following relational expressions are satisfied:

[0029] 0.45 < D1 / D2 < 0.6;

[0030] Among them, D1 is the entrance pupil diameter of the entire all-glass endoscope lens, and D2 is the exit pupil diameter of the entire all-glass endoscope lens.

[0031] Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention have the following characteristics:

[0032] (1) The lenses of the all-glass endoscope lens of the present invention are all made of glass materials, and have characteristics such as good optical performance stability and high temperature resistance;

[0033] (2) The field of view angle of the all-glass endoscope lens of the present invention is 140° ≤ FOV ≤ 145°, effectively increasing the viewing range of the lens and facilitating the user to observe more details;

[0034] (3) The all-glass endoscope lens of the present invention has the characteristics of small volume, small distortion, and high resolution, and has high flexibility.

Description of the Drawings

[0035] Figure 1 It is a schematic structural diagram of an all-glass endoscope lens.

[0036] Figure 2 It is the MTF diagram of the all-glass endoscope lens.

[0037] Figure 3 It is the aberration curve diagram of the all-glass endoscope lens.

[0038] Figure 4 It is the distortion diagram of the all-glass endoscope lens.

Detailed Embodiments

[0039] The following content is the detailed embodiment of the present invention.

[0040] 1. An all-glass endoscope, characterized in that it sequentially includes a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), a seventh lens (L7), and a filter (IR), consisting of a total of 8 lenses; among them, the first lens (L1) and the second lens (L2) form a first lens group (E1), the fourth lens (L4) and the fifth lens (L5) form a second lens group (E2), and the sixth lens (L6) and the seventh lens (L7) form a third lens group (E3);

[0041] The first lens (L1) is made of glass material and has a negative optical power. Its object side is convex and its image side is concave;

[0042] The second lens (L2) is made of glass material and has a positive optical power. Its object side is convex and its image side is concave;

[0043] The third lens (L3) is made of glass and has a positive optical power. Its object side is convex and its image side is convex;

[0044] The fourth lens (L4) is made of glass and has a positive optical power. Its object side is convex and its image side is convex;

[0045] The fifth lens (L5) is made of glass and has a negative optical power. Its object side is concave and its image side is convex;

[0046] The sixth lens (L6) is made of glass and has a positive optical power. Its object side is convex and its image side is convex;

[0047] The seventh lens (L7) is made of glass and has a negative optical power. Its object side is concave and its image side is convex;

[0048] This all-glass endoscope satisfies the following conditional expressions:

[0049] -0.9 ≤ F1 / F ≤ 0;

[0050] 1.59 ≤ F2 / F ≤ 3.5;

[0051] -8 ≤ F3 / F ≤ -6;

[0052] 0.5 ≤ f / F ≤ 2.5;

[0053] where F1, F2, F3, f, and F are the effective focal lengths of the first lens group (E1), the second lens group (E2), the third lens group (E3), the third lens (L3), and the entire all-glass endoscope lens, respectively.

[0054] 2. The all-glass endoscope described above is characterized in that:

[0055] 0.2 ≤ ΣT1 / TTL ≤ 0.5;

[0056] 0.1 ≤ ΣT2 / TTL ≤ 0.35;

[0057] 0.15 ≤ ΣT3 / TTL ≤ 0.3;

[0058] where ΣT1 is the on-axis distance from the object side of the first lens (L1) to the image side of the second lens (L2), ΣT2 is the on-axis distance from the object side of the fourth lens (L4) to the image side of the fifth lens (L5), ΣT3 is the on-axis distance from the object side of the sixth lens (L6) to the image side of the seventh lens (L7), and TTL is the on-axis distance from the object side of the first lens of this all-glass endoscope to the imaging surface.

[0059] 3. The all-glass endoscope described above is characterized in that:

[0060] 140° ≤ FOV ≤ 145°;

[0061] 3.5 ≤ FNO ≤ 4.5;

[0062] Wherein, FOV is the maximum field of view angle of the entire all - glass endoscope lens, and FNO is the F - number of the entire all - glass endoscope lens.

[0063] 4. The all - glass endoscope as described above is characterized in that:

[0064] 0.45 < D1 / D2 < 0.6;

[0065] Wherein, D1 is the entrance pupil diameter of the entire all - glass endoscope lens, and D2 is the exit pupil diameter of the entire all - glass endoscope lens.

[0066] In the lens data table of this embodiment, the unit of the radius of curvature and thickness is mm.

[0067] Figure 1 is a schematic structural diagram of an all - glass endoscope lens.

[0068] Figure 2 is the MTF graph of the all - glass endoscope lens.

[0069] Figure 3 is the aberration curve graph of the all - glass endoscope lens.

[0070] Figure 4 is the distortion graph of the all - glass endoscope lens.

[0071] The following table is the parameter table of the embodiment

[0072] Table 1 Structural parameter table of an all - glass endoscope lens

[0073]

[0074]

[0075] The above content is only an illustration of the optimal implementation case of the content of the present invention, and does not limit the content of the present invention. Any modified content made within the design and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An all-glass endoscope, characterized by: The optical system comprises a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), a seventh lens (L7), and an optical filter (IR), a total of 8 lenses; wherein the first lens (L1) and the second lens (L2) constitute a first lens group (E1), the fourth lens (L4) and the fifth lens (L5) constitute a second lens group (E2), and the sixth lens (L6) and the seventh lens (L7) constitute a third lens group (E3); The first lens (L1) is made of glass, has negative optical power, has a convex object side surface and a concave image side surface; The second lens (L2) is made of glass, has positive power, has a convex object side surface and a concave image side surface; The third lens (L3) is made of glass, has positive power, and has a convex object-side surface and a convex image-side surface. The fourth lens (L4) is made of glass, has positive power, has a convex object-side surface and a convex image-side surface; The fifth lens (L5) is made of glass, has negative optical power, has a concave object side surface and a convex image side surface; The sixth lens (L6) is made of glass, has positive power, has a convex object-side surface and a convex image-side surface; The seventh lens (L7) is made of glass, has negative optical power, has a concave object-side surface and a convex image-side surface; The all-glass endoscope meets the following conditions: -0.9≤F1 / F≤0; 1.59≤F2 / F≤3.5; -8≤F3 / F≤-6; 0.5≤f / F≤2.5; Among them, F1, F2, F3, f, and F are respectively the effective focal lengths of the first lens group (E1), the second lens group (E2), the third lens group (E3), the third lens (L3), and the entire all-glass endoscope lens.

2. The all-glass endoscope according to claim 1, characterized in that: 0.2≤ΣT1 / TTL≤0.5; 0.1≤ΣT2 / TTL≤0.35; 0.15≤ΣT3 / TTL≤0.3; Wherein, ΣT1 is the on-axis distance from the object side of the first lens (L1) to the image side of the second lens (L2), ΣT2 is the on-axis distance from the object side of the fourth lens (L4) to the image side of the fifth lens (L5), ΣT3 is the on-axis distance from the object side of the sixth lens (L6) to the image side of the seventh lens (L7), and TTL is the distance from the object side of the first lens of the all-glass endoscope to the imaging surface on the optical axis.

3. The all-glass endoscope according to claim 1, characterized in that: 140°≤FOV≤145°; 3.5≤FNO≤4.5; Among them, FOV is the maximum field of view of the entire all-glass endoscope lens, and FNO is the F number of the entire all-glass endoscope lens.

4. The all-glass endoscope according to claim 1, characterized in that: 0.45<D1 / D2<0.6; Among them, D1 is the entrance pupil diameter of the entire all-glass endoscope lens, and D2 is the exit pupil diameter of the entire all-glass endoscope lens.

Images