Optical lens of endoscope

Abstract

The utility model relates to the technical field of industrial and medical instruments, in particular to an endoscope optical lens, which comprises protective glass, a first lens, a diaphragm, an optical filter and a second lens which are sequentially arranged along a light incident light path, the first lens and the second lens are both glass aspheric lenses, the first lens is a plano-concave lens, the second lens is a plano-concave lens, and the diaphragm is a diaphragm. The second lens is a biconvex positive lens, and incident light sequentially passes through the protective glass, the first lens, the diaphragm, the optical filter and the second lens and then is imaged so as to form an imaging surface; in the embodiment, through the cooperation of the protective glass, the first lens, the diaphragm, the optical filter and the second lens, a large view field is realized while the miniaturization of the overall structure of the lens is ensured, and the optical performances of high resolution, high stability and the like are met.

Description

Technical Field

[0001] The utility model relates to the technical field of industry and medical equipment, in particular to an endoscope optical lens. Background Art

[0002] An endoscope is an industrial and medical device that is usually composed of a flexible, slender tube that contains a light source and an optical lens. As an important component of the endoscope, the optical lens needs to be small in size for ease of use, while also having a larger field of view to capture a wider image.

[0003] Therefore, designing an endoscope optical lens with small volume and wide viewing angle is very important for those skilled in the art. Utility Model Content

[0004] The technical problem to be solved by the embodiments of the utility model is to provide an endoscope optical lens to meet the demand of having a small volume and a wide viewing angle.

[0005] The utility model discloses an endoscope optical lens, which comprises: a protective glass, a first lens, an aperture, a filter and a second lens which are sequentially arranged along the incident light path of the light, the first lens and the second lens are both glass aspheric lenses, and the first lens is a plano-concave lens, and the second lens is a double-convex positive lens, and the incident light is imaged after passing through the protective glass, the first lens, the aperture, the filter and the second lens in sequence to form an imaging surface.

[0006] Optionally, the object-side surface of the first lens is a plane, and the image-side surface of the first lens is a concave surface; the object-side surface of the second lens is a convex surface, and the image-side surface of the second lens is a convex surface.

[0007] Optionally, a ratio of a distance from a side surface of the first lens close to the protective glass to an imaging surface to a focal length is not less than 2 and not greater than 3.

[0008] Optionally, the ratio of the total optical length of the endoscope optical lens to its focal length is not greater than 2.5.

[0009] Optionally, the ratio of the focal length f of the endoscope optical lens, the focal length f1 of the first lens, and the focal length f2 of the second lens satisfies: 30 <f1 / f<33,0.5<f2 / f<1.5。

[0010] Optionally, the first lens satisfies: Nd≤1.5, Vd≥50.0; the second lens satisfies: Nd≤1.5, Vd≥50.0; wherein Nd is the refractive index, and Vd is the Abbe constant.

[0011] Optionally, the F number of the endoscope optical lens is not greater than 5.3.

[0012] Optionally, the endoscopic optical lens satisfies: H / f≥1.53; wherein H is the image height of the endoscopic optical lens, and f is the focal length of the endoscopic optical lens.

[0013] Optionally, the imaging band of the endoscope optical lens is 400nm to 700nm.

[0014] Optionally, the protective glass is sapphire, and the first lens, the second lens and the filter are all quartz glass.

[0015] Compared with the prior art, the beneficial effect of the endoscope optical lens provided by the embodiment of the utility model is: by designing an endoscope optical lens, including a protective glass, a first lens, an aperture, a filter and a second lens arranged in sequence along the incident light path of the light, the first lens and the second lens are both glass aspherical lenses, and the first lens is a plano-concave lens, and the second lens is a double convex positive lens; through the coordination between the protective glass, the first lens, the aperture, the filter and the second lens, a large field of view is achieved while ensuring the miniaturization of the overall structure of the lens, and optical properties such as high resolution and high stability are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution of the utility model will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0017] Figure 1 It is a schematic structural diagram of an endoscope optical lens provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, a preferred embodiment of the present utility model is described in detail.

[0019] like Figure 1 As shown, the utility model provides a specific embodiment of an endoscope optical lens.

[0020] An endoscope optical lens, reference Figure 1 The endoscope optical lens includes a protective glass 1, a first lens 2, an aperture 3, a filter 4 and a second lens 5 which are sequentially arranged along the incident light path of the light. The first lens 2 and the second lens 5 are both glass aspherical lenses, and the first lens 2 is a plano-concave lens, and the second lens 5 is a double-convex positive lens. The incident light sequentially passes through the protective glass 1, the first lens 2, the aperture 3, the filter 4 and the second lens 5 to form an imaging surface.

[0021] Specifically, refer to Figure 1 The protective glass 1 is arranged at the incident end of the light, in front of the lens, to protect the lens surface from damage and to prevent the key optical components inside the lens from being scratched, contaminated or otherwise damaged, thereby ensuring the stability and reliability of the system and improving the service life of the endoscope optical lens.

[0022] Further, refer to Figure 1 The first lens 2 is arranged behind the protective glass 1. The first lens 2 is a glass aspherical lens. By adopting the aspherical design, the number of lenses in the entire endoscope optical lens can be reduced, and the size of the first lens 2 can be reduced, thereby enhancing the imaging quality and improving the resolution. The first lens 2 is specifically a plano-concave lens. The plano-concave lens has a flat side and a concave side. The concave surface can make the optical fiber converge or diverge. According to the concavity of the lens and the angle of incidence of the light, the effect of collecting or diverging the light can be achieved. By cooperating with the plano-concave lens and other lenses, the light convergence or divergence effect can also be adjusted.

[0023] Further, refer to Figure 1 The filter 4 is specifically an infrared filter 4, which can filter out infrared band light; the aperture 3 is arranged at the front end of the filter 4, mainly used to control the propagation of light and limit the incident range of light. It can control the size and shape of light by limiting the incident range of light, prevent unnecessary light from entering the system, thereby reducing scattering and interference to improve imaging quality, and the aperture 3 can also reduce the scattering of light, avoid unnecessary reflection and refraction of light inside the system, reduce the aberration of the optical system, and improve clarity and contrast; by setting the aperture 3 at the front end of the infrared filter 4, a large field of view can be designed, and the size of the first lens 2 can be reduced to achieve the effect of reducing the overall structure of the endoscope optical lens.

[0024] Further, refer to Figure 1 The second lens 5 is arranged at the rear end of the filter 4. The second lens 5 is a glass aspherical lens. By adopting the aspherical design, the number of lenses in the entire endoscope optical lens can be reduced, and the size of the second lens 5 can also be reduced, thereby enhancing the imaging quality and improving the resolution. The second lens 5 is specifically a double convex positive lens. The second lens 5 has two convex lens surfaces, which can converge the incident light to a focal point to form a clear real image. According to the focal length of the second lens 5 and the distance from the object to the lens, the size and clarity of the image can be adjusted. Moreover, by adjusting the position of the second lens 5 or changing the angle of the incident light, the light can be focused to a specific focal point. By adjusting the focal length and position of the second lens 5, the magnification effect of the object image can be achieved.

[0025] The second lens 5 converges the incident light to a focal point and then forms an image to form an imaging surface at the rear end.

[0026] In one embodiment, reference Figure 1 The object side surface of the first lens 2 is a plane, and the image side surface of the first lens 2 is a concave surface; the object side surface of the second lens 5 is a convex surface, and the image side surface of the second lens 5 is a convex surface.

[0027] Specifically, the concave surface of the first lens 2 is mainly used to converge light in a large field of view, and can focus the incident light in the large field of view to achieve the effect of a large field of view and a short focal length. It can effectively reduce the diameter of the lens, thereby ensuring that there is enough assembly space for the back focus; the convex surface of the second lens 5 has a scattering effect, and can diverge the focused light to obtain a larger field of view.

[0028] In one embodiment, the ratio of the distance from the front surface of the first lens 2 to the imaging plane to the focal length is not less than 2 and not greater than 3.

[0029] Specifically, the front surface of the first lens 2 refers to a side surface of the first lens 2 close to the protective glass 1 , and the imaging surface refers to an imaging surface formed after the second lens 5 converges the incident light to a focus.

[0030] In one embodiment, the ratio of the total optical length of the endoscope optical lens to its focal length is no greater than 2.5.

[0031] Specifically, by limiting the ratio between the total optical length of the endoscope optical lens and its focal length, it is possible to achieve optimal optical performance, system stability and imaging quality while ensuring that the endoscope optical lens structure is compact and small.

[0032] In one embodiment, the ratio of the focal length f of the endoscope optical lens, the focal length f1 of the first lens 2, and the focal length f2 of the second lens 5 satisfies: 30 <f1 / f<33,0.5<f2 / f<1.5。

[0033] Specifically, the ratio of the focal length f1 of the first lens 2 to the total focal length f of the endoscope optical lens will be greater than 30 and less than 33; the ratio of the focal length f2 of the second lens 5 to the total focal length f of the endoscope optical lens will be greater than 0.5 and less than 1.5.

[0034] In one embodiment, the first lens 2 satisfies: Nd≤1.5, Vd≥50.0; the second lens 5 satisfies: Nd≤1.5, Vd≥50.0; wherein Nd is the refractive index, and Vd is the Abbe constant.

[0035] Specifically, the refractive index is an important parameter in optics and has a significant impact on the imaging quality. The change in the refractive index will affect the spherical aberration and astigmatism of the lens, and the refractive index of the lens will also affect its transmittance. In this embodiment, the refractive index of the first lens 2 and the second lens 5 is limited, which can optimize the shape of the aspheric lens and effectively reduce aberrations, thereby improving the final imaging quality.

[0036] In one embodiment, the center distance between the protective glass 1 and the first lens 2 is 0.03 mm, the center distance between the first lens 2 and the aperture 3 is 0.17 mm, the center distance between the aperture 3 and the filter 4 is 0 mm, and the center distance between the filter 4 and the second lens 5 is 0.02 mm.

[0037] Specifically, in an optical system, a combination of multiple lenses is usually required to achieve a specific optical function, and the center distance between different lenses will affect the propagation path of light, which may eventually cause the position, size or clarity of the image to change. In this embodiment, by limiting the center distances between the protective glass 1 and the first lens 2, between the first lens 2 and the aperture 3, between the aperture 3 and the filter 4, and between the filter 4 and the second lens 5, not only can the desired imaging effect be achieved, but also the stability of the lens during operation can be ensured, thereby improving the reliability of the system.

[0038] In one embodiment, the F number of the endoscope optical lens is not greater than 5.3.

[0039] Specifically, the smaller the F number, the larger the aperture, and the more light enters, which is suitable for shooting in a dimly lit environment to increase the brightness of the image; the larger the F number, the smaller the aperture and the deeper the depth of field, which is suitable for shooting scenes that require a larger depth of field so that the foreground and background objects can remain clear. At the same time, the lens has different imaging clarity and resolution performance at different F numbers.

[0040] Since endoscopes generally work under low-light conditions, a smaller F number can allow more light to enter the system, improve imaging effects, and reduce noise and blur.

[0041] In one of the embodiments, the endoscope optical lens satisfies: H / f≥1.53; wherein H is the image height of the endoscope optical lens, and f is the focal length of the endoscope optical lens.

[0042] In one embodiment, the imaging wavelength band of the endoscope optical lens is 400nm to 700nm.

[0043] In one embodiment, the protective glass 1 satisfies: R1=∞mm, R2=∞mm, Nd=1.772, Vd=72.2, D=0.30mm; the first lens 2 satisfies: R1=∞mm, R2=-10.45mm, Nd=1.49, Vd=70.4, D=0.21mm; the second lens 5 satisfies: R1=0.44mm, R2=-0.67mm, Nd=1.44, Vd=94.5, D=0.43mm; the filter 4 satisfies: R1=∞mm, R2=∞mm, Nd=1.52, Vd=64.2, D=0.2mm.

[0044] Among them, R1 refers to the radius of curvature of the center point of the first side of the lens, R2 refers to the radius of curvature of the center point of the second side of the lens, Nd refers to the refractive index of the lens, Vd refers to the Abbe constant of the lens, and D refers to the center thickness of the lens. The selection of R1 and R2 affects the imaging characteristics of the lens, such as focusing ability, distortion and aberration. The refractive index is used to change the propagation and refraction angle of light in the lens, and the Abbe constant describes the dispersion properties of the lens. Appropriate selection of the center thickness can control the shape, thickness and weight of the lens, and at the same time affect the imaging characteristics of the lens.

[0045] In one embodiment, the protective glass 1 is made of sapphire, and the first lens 2, the second lens 5 and the filter 4 are all made of quartz glass.

[0046] Specifically, the hardness of sapphire is second only to diamond, so it has very high wear resistance and can maintain its luster for a long time. Sapphire has excellent transparency, which gives it outstanding optical properties. Sapphire has high chemical stability and is not easily susceptible to chemical corrosion, which makes its protective function stronger.

[0047] Furthermore, quartz glass has high temperature stability, chemical inertness and excellent optical properties. It has excellent optical transparency and refractive index, making quartz glass an ideal material for making lenses.

[0048] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present utility model rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present utility model.

Claims

1. An endoscope optical lens, characterized in that: include: A protective glass, a first lens, an aperture, a filter and a second lens are arranged in sequence along the incident light path of the light, the first lens and the second lens are both glass aspheric lenses, the first lens is a plano-concave lens, and the second lens is a double-convex positive lens. The incident light passes through the protective glass, the first lens, the aperture, the filter and the second lens in sequence to form an imaging surface.

2. The endoscope optical lens according to claim 1, characterized in that: The object side surface of the first lens is a plane surface, and the image side surface of the first lens is a concave surface; the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a convex surface.

3. The endoscope optical lens according to claim 1, characterized in that: The ratio of the distance from the side surface of the first lens close to the protective glass to the imaging surface to the focal length is not less than 2 and not greater than 3.

4. The endoscope optical lens according to claim 1, characterized in that: The ratio of the total optical length of the endoscope optical lens to its focal length is no more than 2.

5.

5. The endoscope optical lens according to claim 1, characterized in that: The ratio between the focal length f of the endoscope optical lens, the focal length f1 of the first lens and the focal length f2 of the second lens satisfies: 30 <f1 / f<33,0.5<f2 / f<1.5。 6. The endoscope optical lens according to claim 1, characterized in that: The first lens satisfies: Nd≤1.5, Vd≥50.0; the second lens satisfies: Nd≤1.5, Vd≥50.0; wherein Nd is the refractive index, and Vd is the Abbe constant.

7. The endoscope optical lens according to claim 1, characterized in that: The F number of the endoscope optical lens is not greater than 5.

3.

8. The endoscope optical lens according to claim 1, characterized in that: The endoscope optical lens satisfies: H / f≥1.53; wherein H is the image height of the endoscope optical lens, and f is the focal length of the endoscope optical lens.

9. The endoscope optical lens according to claim 1, characterized in that: The imaging wavelength band of the endoscope optical lens is 400nm to 700nm.

10. The endoscope optical lens according to claim 1, characterized in that: The protective glass is sapphire, and the first lens, the second lens and the filter are all made of quartz glass.

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