A wide-angle endoscope optical system

Abstract

The present invention provides a wide-angle endoscope optical system, which includes, from the object side to the image side, a first lens with negative optical power, a second lens with negative optical power, an aperture, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, and a filter. The optical system satisfies the following conditional formula: f / H(L1r1)<2; H(L1r1) / IMH<1.5; wherein f is the focal length of the wide-angle endoscope optical system, H(L1r1) is the height corresponding to the main light corresponding to the maximum image height during normal observation when passing through the object side of the first lens, and IMH is the maximum image height on the photosensitive surface of the chip corresponding to normal observation. The wide-angle endoscope optical system involved in the present invention has the advantages of large depth of field, wide field of view, small size, high relative illumination, etc.

Description

[Technical field]

[0001] The present invention comprises a wide-angle endoscope optical system. [Background technology]

[0002] With the development of science and technology, medical equipment is constantly being updated. As a medical optical detection instrument, the endoscope can enter the human body through the natural channels of the human body or through a small incision made during surgery to examine internal organs, determine the location and scope of lesions, take pictures of diseased tissues or perform minimally invasive surgery. In addition, image processing technology can be used to perform quantitative analysis and quantitative diagnosis on images of diseased tissues.

[0003] In order to better adapt to the various environments inside the human body and improve the accuracy of doctors' diagnosis, it is necessary to further reduce the volume of the endoscopic optical system, and on this basis improve the clarity of its imaging and increase the imaging range; the wide-angle endoscopic optical system involved in the present invention has the advantages of large depth of field, wide field of view, small volume, high relative illumination, etc., and has a great competitive advantage. [Summary of the invention]

[0004] The present invention provides a wide-angle endoscope optical system with high resolution and a large field of view. The optical system has a compact structure and can reduce the volume to a great extent while ensuring a large imaging range. The optical aperture of the optical system is small, which is conducive to increasing the relative illumination. At the same time, the present invention can obtain good imaging results within the object distance range of 3mm to 100mm, meeting the needs of practical applications.

[0005] The technical solution adopted by the present invention is:

[0006] A wide-angle endoscope optical system includes, from the object side to the image side, a first lens with negative optical power, a second lens with negative optical power, an aperture, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, and a filter. The optical system satisfies the following conditional formula:

[0007] f / H(L1r1)<2; (1)

[0008] H(L1-1) / IMH<1.5; (2)

[0009] Among them, f is the focal length of the wide-angle endoscope optical system, H(L1r1) is the height corresponding to the main light corresponding to the maximum image height during normal observation passing through the object side surface of the first lens, and IMH is the maximum image height on the chip photosensitive surface corresponding to normal observation.

[0010] The first lens of the optical system has negative focal power, its object side surface is convex, and its image side surface is concave; the second lens has negative focal power, its object side surface is concave, and its image side surface is convex; the third lens has positive focal power, its object side surface is convex, and its image side surface is convex; the fourth lens has positive focal power, its object side surface is concave, and its image side surface is convex; the fifth lens has negative focal power, its object side surface is concave, and its image side surface is convex; the entire optical system is composed of at least 5 plastic lenses.

[0011] In order to increase the field of view of the optical system as much as possible, the first lens has negative optical power and a large aperture to collect as much light as possible. The image side of the first lens is concave, the object side of the third lens is convex, and an anti-telephoto structure is adopted, which is conducive to increasing the field of view, reducing the total length of the optical system, and making the system structure compact.

[0012] The above wide-angle endoscope optical system is characterized by:

[0013] 0.1 <f / TTL<0.3; (3)

[0014] Wherein, TTL is the distance from the object side to the imaging surface of the optical system on the optical axis, and f is the effective focal length of the optical system.

[0015] A wide-angle endoscope optical system satisfying formula (3) can ensure a shorter working distance, a larger depth of field and a larger field of view, while having a higher resolution.

[0016] The above wide-angle endoscope optical system is characterized by:

[0017] -2 <f1 / f<0; (4)

[0018] -10 <f2 / f<0; (5)

[0019] 0 <f3 / f<2; (6)

[0020] 1.3 <f4 / f<1.9; (7)

[0021] -2.5 <f5 / f<-1.5; (8)

[0022] Among them, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, and f is the effective focal length of the optical system.

[0023] A wide-angle endoscope optical system that satisfies equations (4), (5), and (6) can collect as much light as possible while allowing the light to enter the optical system smoothly, which is beneficial to reducing optical aberrations and lowering its tolerance sensitivity, while making the optical structure compact and meeting the needs of miniaturization.

[0024] A wide-angle endoscope optical system that satisfies equations (7) and (8) is beneficial for reducing optical aberrations and chromatic aberrations while reducing the total optical length.

[0025] The above wide-angle endoscope optical system is characterized by:

[0026] 0 <Dr1r4 / TTL<0.6; (9)

[0027] 1 <Dr1r4 / f<4; (10)

[0028] Wherein, Dr1r4 is the on-axis distance from the object side S1 of the first lens to the image side S4 of the second lens of the optical system, TTL is the distance from the object side to the imaging surface of the optical system on the optical axis, and f is the effective focal length of the optical system.

[0029] The wide-angle endoscope optical system that satisfies formula (9) is beneficial to reducing the total optical length while ensuring that the system has a larger field of view.

[0030] A wide-angle endoscope optical system that satisfies equation (10) can effectively improve the distortion of the system.

[0031] The above wide-angle endoscope optical system is characterized by:

[0032] 0 <Dr5r10 / TTL<0.4; (11)

[0033] 1 <Dr5r10 / f<3; (12)

[0034] Wherein, Dr6r11 is the on-axis distance from the object side S6 of the third lens to the image side S11 of the fifth lens of the optical system, TTL is the distance from the object side to the imaging plane of the optical system on the optical axis, and f is the effective focal length of the optical system.

[0035] A wide-angle endoscope optical system that satisfies formula (11) is beneficial for ensuring a smaller total optical length and reducing the optical aberration of the system.

[0036] A wide-angle endoscope optical system that satisfies formula (12) is beneficial to reducing the distortion and field curvature of the system.

[0037] The above wide-angle endoscope optical system is characterized by:

[0038] 2 <Dr7i / f<4; (13)

[0039] Wherein, Dr7i is the axial distance from the image side surface S7 of the third lens of the optical system to the image plane, and f is the effective focal length of the optical system.

[0040] A wide-angle endoscope optical system that satisfies formula (13) is beneficial to reducing the total optical length of the system and ensuring that the system has a larger field of view.

Brief Description of the Drawings

[0041] Figure 1 It is a schematic structural diagram of the wide-angle endoscope optical system of the present invention;

[0042] Figure 2 is a distortion diagram of the wide-angle endoscope optical system of the present invention;

[0043] Figure 3 is an aberration curve diagram of the wide-angle endoscope optical system of the present invention; [Specific implementation method]

[0044] The present invention is described in further detail below in conjunction with the accompanying drawings.

[0045] Please refer to Figure 1 A wide-angle endoscope optical system, characterized in that it includes, from the object side to the image side, a first lens with negative optical power, a second lens with negative optical power, an aperture, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, and a filter. The optical system satisfies the following conditional formula:

[0046] f / H(L1r1)<2; (1)

[0047] H(L1-1) / IMH<1.5; (2)

[0048] Among them, f is the focal length of the wide-angle endoscope optical system, H(L1r1) is the height corresponding to the main light corresponding to the maximum image height during normal observation passing through the object side surface of the first lens, and IMH is the maximum image height on the chip photosensitive surface corresponding to normal observation.

[0049] The first lens of the optical system has negative focal power, its object side surface is convex, and its image side surface is concave; the second lens has negative focal power, its object side surface is concave, and its image side surface is convex; the third lens has positive focal power, its object side surface is convex, and its image side surface is convex; the fourth lens has positive focal power, its object side surface is concave, and its image side surface is convex; the fifth lens has negative focal power, its object side surface is concave, and its image side surface is convex; the entire optical system is composed of at least 5 plastic lenses.

[0050] The wide-angle endoscope optical system involved in the present invention has the advantages of large depth of field, wide field of view, small size, etc., and has good resolution in both near and far views.

[0051] The following are some optical parameters of the wide-angle endoscope optical system embodiment. In the lens data table of this embodiment, the units of radius and thickness are mm, and S (solid line) and T (dashed line) in the aberration curve diagram represent the sagittal image plane and the meridional image plane, respectively.

[0052] The following table is a lens data table of a specific embodiment.

[0053] Table 1 is the structural parameters of the wide-angle endoscope

[0054] Surface Type Radius(mm) Thickness(mm) Glass Object Sphere Infinity 6.5233 1 Asphere 11.8217 0.383 1.544:56.2 2 Asphere 0.4767 0.5217 3 Asphere -1.5735 1.028 1.642:22.4 4 Asphere -4.317 0.01 Stop Sphere Infinity 0.01 6 Asphere 0.8970 0.506 1.544:56.2 7 Asphere -1.0872 0.1969 8 Asphere -13.1794 0.5098 1.544:56.2 9 Asphere -0.5143 0.01 10 Asphere -0.5734 0.2200 1.642:22.4 11 Asphere -2.7219 0.44 12 Sphere Infinity 0.61 1.516:64.2 13 Sphere Infinity 0.0730 Image Sphere Infinity 0

[0055] Table 1

[0056] Table 2 shows the ratio of the sag height to the radius R of the first lens L1 of the wide-angle endoscope system

[0057]

[0058]

[0059] Table 2

[0060] Table 3 shows the ratio of the sagittal height to the radius R of the second lens L2 of the wide-angle endoscope system

[0061]

[0062] Table 3

[0063] Table 4 shows the ratio of the sagittal height to the radius R of the third lens L3 of the wide-angle endoscope system

[0064]

[0065] Table 4

[0066] Table 5 shows the ratio of the sagittal height to the radius R of the fourth lens L4 of the wide-angle endoscope system

[0067]

[0068]

[0069] Table 5

[0070] Table 6 shows the ratio of the sag height to the radius R of the fifth lens L5 of the wide-angle endoscope system

[0071]

[0072] Table 6.

Claims

1. A wide-angle endoscope optical system, characterized in that: The optical system includes, from the object side to the image side, a first lens with negative power, a second lens with negative power, an aperture, a third lens with positive power, a fourth lens with positive power, a fifth lens with negative power, and a filter. The number of lenses with power is five. The optical system satisfies the following conditional formula: f / H(L1r1)<2; H(L1r1) / IMH<1.5; Wherein, f is the focal length of the wide-angle endoscope optical system, H(L1r1) is the height corresponding to the principal ray corresponding to the maximum image height during conventional observation passing through the object side surface of the first lens, and IMH is the maximum image height on the photosensitive surface of the chip corresponding to conventional observation; -2 <f1 / f<0; -10 <f2 / f<0; 0 <f3 / f<2; 1.3 <f4 / f<1.9; -2.5 <f5 / f<-1.5; Among them, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, and f5 is the effective focal length of the fifth lens.

2. The wide-angle endoscope optical system according to claim 1, characterized in that: The first lens of the optical system has a convex object side surface and a concave image side surface; the second lens has a concave object side surface and a convex image side surface; the third lens has a convex object side surface and a convex image side surface; the fourth lens has a concave object side surface and a convex image side surface; and the fifth lens has a concave object side surface and a convex image side surface.

3. The wide-angle endoscope optical system according to claim 1 or 2, characterized in that: 0.1 <f / TTL<0.3; Wherein, TTL is the distance from the object side to the imaging surface of the optical system on the optical axis.

4. The wide-angle endoscope optical system according to claim 1 or 2, characterized in that: 0 <Dr1r4 / TTL<0.6; 1 <Dr1r4 / f<4; Wherein, Dr1r4 is the on-axis distance from the object side surface S1 of the first lens to the image side surface S4 of the second lens of the optical system, and TTL is the distance from the object side surface to the imaging surface of the optical system on the optical axis.

5. The wide-angle endoscope optical system according to claim 1 or 2, characterized in that: 0 <Dr6r11 / TTL<0.4; 1 <Dr6r11 / f<4; Wherein, Dr6r11 is the on-axis distance from the object side surface S6 of the third lens to the image side surface S11 of the fifth lens of the optical system, and TTL is the distance from the object side surface to the imaging surface of the optical system on the optical axis.

6. The wide-angle endoscope optical system according to claim 1 or 2, characterized in that: 2 <Dr7i / f<4; Wherein, Dr7i is the axial distance from the image side surface S7 of the third lens of the optical system to the image plane.

Images