Gastrointestinal objective lens

Abstract

The utility model relates to a kind of digestive tract objective lens, the optical structure of digestive tract objective lens includes first lens, second lens, third lens, diaphragm, fourth lens, fifth lens, sixth lens sequentially arranged from object side to image side direction along optical axis, the first lens, second lens, third lens combination is front group system, fourth lens, fifth lens, sixth lens combination is rear group system, front group system is divided into gastroscope front group system and enteroscope front group system two kinds of forms, rear group system is common to gastroscope front group system and enteroscope front group system, the optical total length after the combination of gastroscope front group system and rear group system, the optical total length after the combination of enteroscope front group system and rear group system is identical. The utility model design is reasonable, and aberration is balanced reasonably, with small volume, imaging quality is good, lens common rear group, gastroscope system and enteroscope system common module and the like features.

Description

Technical fields:

[0001] This utility model relates to a digestive tract objective lens. Background technology:

[0002] Gastrointestinal endoscopes are of great significance for the early diagnosis of gastrointestinal tumors, serving as the gold standard for early screening of gastrointestinal cancers and a core instrument for endoscopic gastrointestinal surgery, thus safeguarding public health. Gastrointestinal endoscopes are generally divided into gastroscopes and colonoscopes based on their natural passageways. The field of view of gastroscopes differs from that of colonoscopes, with the colonoscope generally having a larger field of view than the gastroscope. This invention provides a gastrointestinal objective lens that features a different front group but a shared rear group, and a consistent total optical length. Utility model content:

[0003] The purpose of this invention is to provide a digestive tract objective lens that features differences in the front group and shared rear group, while maintaining a consistent total optical length.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is: a digestive tract objective lens, the optical structure of which includes a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side. The first lens, the second lens, and the third lens are combined to form a front group system, and the fourth lens, the fifth lens, and the sixth lens are combined to form a rear group system. The front group system is divided into two forms: a gastroscopy front group system and a colonoscopy front group system. The rear group system is shared by the gastroscopy front group system and the colonoscopy front group system. The total optical length of the combined gastroscopy front group system and the rear group system is the same as that of the combined colonoscopy front group system and the rear group system.

[0005] Furthermore, the first lens is a plano-concave lens, the second lens is a negative meniscus lens, the third lens is a plano-convex lens, the fourth lens is a biconvex lens, the fifth lens is a biconvex lens, the sixth lens is a biconcave lens, and the fifth and sixth lenses are combined to form a cemented doublet lens.

[0006] Furthermore, the absolute focal length of the first lens is 1mm-2mm; the absolute focal length of the second lens is 2mm-4mm with its concave surface facing the aperture stop; the absolute focal length of the third lens is 1mm-2mm with its flat surface facing the aperture stop; the absolute focal length of the fourth lens is 1mm-2mm; the absolute focal length of the fifth lens is 1mm-2mm; the absolute focal length of the sixth lens is 1mm-2mm; and the absolute focal length of the cemented doublet lens is 50mm-100mm.

[0007] Furthermore, the first lens, the second lens, the third lens, the aperture stop, the fourth lens, the fifth lens, and the sixth lens are all spherical lenses made of glass.

[0008] Further, the overall optical length is the same after the combination of the front group system and the rear group system.

[0009] Further, the effective focal length f1 of the front group system of the gastroscope and the effective focal length f2 of the front group system of the colonoscope satisfy: 0.5 < f1 / f2 < 2; the effective focal length f1 of the front group system of the gastroscope and the effective focal length f0 of the rear group system satisfy: 0.5 < f1 / f0 < 2; the effective focal length f2 of the front group system of the colonoscope and the effective focal length f0 of the rear group system satisfy: 0.5 < f2 / f0 < 2.

[0010] Further, after the combination of the front group system and the rear group system of the gastroscope, it forms a gastroscope system with a FOV of 130° - 150°; after the combination of the front group system and the rear group system of the colonoscope, it forms a colonoscope system with a FOV of 160° - 180°.

[0011] Further, the dispersion coefficient of the fifth lens is between 50 - 70; the dispersion coefficient of the sixth lens is between 10 - 30.

[0012] Further, the thermal expansion coefficients of the fifth lens and the sixth lens are between 6 PPM / K - 9 PPM / K.

[0013] Compared with the prior art, the present utility model has the following effects: The present utility model is reasonably designed, with reasonable balance of aberrations, and has the characteristics of small volume, good imaging quality, sharing the rear group of the lens, and sharing modules between the gastroscope system and the colonoscope system. BRIEF DESCRIPTION OF THE DRAWINGS:

[0014] Figure 1 is a schematic structural diagram of the gastroscope system in an embodiment of the present utility model;

[0015] Figure 2 is a schematic structural diagram of the colonoscope system in an embodiment of the present utility model;

[0016] Figure 3 is an image quality evaluation diagram of the gastroscope system;

[0017] Figure 4 is an image quality evaluation diagram of the colonoscope system.

[0018] Figure 1 In the figures:

[0019] 11 - First lens; 12 - Second lens; 13 - Third lens; 04 - Fourth lens; 05 - Fifth lens; 06 - Sixth lens; 07 - Aperture; 08 - Filter;

[0020] Figure 2 In the figures:

[0021] 21 - First lens; 22 - Second lens; 23 - Third lens. SPECIFIC EMBODIMENTS:

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] like Figures 1-2 As shown, this utility model discloses a digestive tract objective lens, which has two forms of the front group system, corresponding to gastroscopy and colonoscopy respectively, and the rear group is shared by both forms with the same total optical length. Specifically, the optical structure of the digestive tract objective lens includes a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, a sixth lens, and a filter arranged sequentially along the optical axis from the object side to the image side. The first lens, second lens, and third lens combine to form the front group system, and the fourth lens, fifth lens, and sixth lens combine to form the rear group system. The front group system is divided into two forms according to the type of digestive tract endoscope: a gastroscopy front group system and a colonoscopy front group system. The rear group system is shared by both the gastroscopy front group system and the colonoscopy front group system. The gastroscopy front group system and the rear group system together form a gastroscopy system, and the colonoscopy front group system and the rear group system together form a colonoscopy system. The total optical length of the combined gastroscopy front group system and the combined colonoscopy front group system are the same.

[0025] In this embodiment, the first lens is a plano-concave lens with an absolute focal length of 1mm-2mm. The concave surface faces the aperture stop. It is made of a grade 1 acid- and weather-resistant material, and the flat surface is beneficial for cleaning the digestive endoscope during operation.

[0026] In this embodiment, the second lens is a negative meniscus lens with an absolute focal length of 2mm-4mm. Its concave surface faces the aperture stop, which is beneficial for adjusting the angle of light and balancing aberrations.

[0027] In this embodiment, the third lens is a plano-convex lens with an absolute focal length of 1mm-2mm. The plane faces the aperture stop, which helps to balance phase difference and reduce manufacturing difficulty.

[0028] In this embodiment, the fourth lens is a biconvex lens with an absolute focal length of 1mm-2mm.

[0029] In this embodiment, the fifth lens is a biconvex lens with an absolute focal length of 1mm-2mm.

[0030] In this embodiment, the sixth lens is a biconcave lens with an absolute focal length of 1mm-2mm.

[0031] In this embodiment, the fifth lens and the sixth lens are combined to form a cemented doublet lens with an absolute focal length of 50mm-100mm, which is beneficial for adjusting the incident angle of the principal ray to match the sensor.

[0032] In this embodiment, the first lens, the second lens, the third lens, the aperture stop, the fourth lens, the fifth lens, and the sixth lens are all spherical lenses made of glass.

[0033] In this embodiment, the total optical length of the front system and the rear system is the same after combination.

[0034] In this embodiment, the total optical length of the gastroscopy system and the colonoscopy system is the same, both being 6.5mm, which facilitates the sharing of the imaging module between the gastroscopy system and the colonoscopy system.

[0035] In this embodiment, the effective focal length f1 of the pre-endoscopic system and the effective focal length f2 of the pre-endoscopic system satisfy: 0.5 <f1 / f2<2。

[0036] In this embodiment, the effective focal length f1 of the anterior group system and the effective focal length f0 of the posterior group system of the endoscope satisfy: 0.5 <f1 / f0<2。

[0037] In this embodiment, the effective focal length f2 of the anterior group system and the effective focal length f0 of the posterior group system satisfy: 0.5 <f2 / f0<2。

[0038] In this embodiment, the gastroscopy system is formed by combining the anterior and posterior gastroscopy systems, with a field of view (FOV) of 130°-150°.

[0039] In this embodiment, the pre- and post-colonoscope systems are combined to form a colonoscopy system with a field of view (FOV) of 160°-180°.

[0040] In this embodiment, the front-end system adopts a negative-then-positive structure, which can effectively increase the field of view and balance phase aberration. The rear-end system uses a combination of positive lenses and cemented lenses to balance the residual phase aberration of the front-end system and adjust the light angle to match the sensor.

[0041] In this embodiment, the dispersion coefficient of the fifth lens is between 50 and 70.

[0042] In this embodiment, the dispersion coefficient of the sixth lens is between 10 and 30.

[0043] In this embodiment, the coefficients of thermal expansion of the fifth and sixth lenses are between 6 PPM / K and 9 PPM / K, which helps to reduce the aging effects caused by repeated high-temperature sterilization.

[0044] In this embodiment, the specific parameters of each lens are as follows: (R1 refers to the surface radius of curvature along the object plane direction of the optical path, R2 refers to the surface radius of curvature along the image plane direction of the optical path, and D refers to the center thickness. Unit: mm)

[0045] Pre-endoscopic system:

[0046] The first lens has R1 = ∞, R2 = 1.029, material: H-ZLAF68N, D = 0.3;

[0047] Air thickness D = 0.387;

[0048] The second lens has R1 = 2.102, R2 = 1.022, material: H-ZLAF66, D = 0.3;

[0049] Air thickness D = 0.139;

[0050] The third lens has R1 = 1.348, R2 = ∞, material: H-ZLAF4LA, D = 0.67; 5

[0051] Air thickness D = 0.680;

[0052] Pre-colonoscopy system:

[0053] The first lens has R1 = ∞, R2 = 1.036, material: H-ZLAF68N, D = 0.3;

[0054] Air thickness D = 0.410;

[0055] The second lens has R1 = 2.392, R2 = 0.972, material: H-FK61B, D = 0.3;

[0056] Air thickness D = 0.178;

[0057] The third lens has R1 = 1.604, R2 = ∞, material: H-ZLAF68N, D = 0.638;

[0058] Air thickness D = 0.680;

[0059] Rear group system:

[0060] Aperture

[0061] Air thickness D = 0.05;

[0062] The fourth lens has R1 = 15.346, R2 = -1.455, material: H-LAK51A, D = 0.668;

[0063] Air thickness D = 0.05;

[0064] The fifth lens has R1 = 1.552, R2 = -1.364, and is made of H-K9L material. D = 0.811.

[0065] The sixth lens has R1 = -1.364, R2 = 15.476, material: H-ZLAF90, and D = 0.3.

[0066] like Figure 3 The gastroscopy system shown has an MTF close to the diffraction limit, and its dot pattern is smaller than the Airy disk; as shown Figure 4 The colonoscopy system shown has an MTF close to the diffraction limit, and its dot pattern is smaller than the Airy disk.

[0067] If this utility model discloses or relates to mutually fixedly connected parts or structural components, then, unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured using a casting process) (except where it is obviously impossible to use an integral forming process).

[0068] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this utility model to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0069] Any component provided by this utility model can be assembled from multiple individual components, or it can be a single component manufactured by a one-piece molding process.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. A digestive tract objective lens, characterized in that: The optical structure of the digestive tract objective lens includes a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, and a sixth lens arranged in sequence from the object side to the image side along the optical axis. The first lens, the second lens, and the third lens are combined into a front group system, and the fourth lens, the fifth lens, and the sixth lens are combined into a rear group system. The front group system has two forms: the gastroscope front group system and the colonoscope front group system; the rear group system is shared by the gastroscope front group system and the colonoscope front group system, and the overall optical length after the combination of the gastroscope front group system and the rear group system is the same as that after the combination of the colonoscope front group system and the rear group system.

2. The digestive tract objective lens according to claim 1, characterized in that: The first lens is a plano-concave lens, the second lens is a negative meniscus lens, the third lens is a plano-convex lens, the fourth lens is a biconvex lens, the fifth lens is a biconvex lens, the sixth lens is a biconcave lens, and the fifth lens and the sixth lens are combined into a doublet lens.

3. A digestive tract objective lens according to claim 2, characterized in that: The absolute value of the focal length of the first lens is: 1 mm - 2 mm; the concave surface of the second lens faces the aperture stop, and the absolute value of the focal length is: 2 mm - 4 mm; the plane of the third lens faces the aperture stop, and the absolute value of the focal length is: 1 mm - 2 mm; the absolute value of the focal length of the fourth lens is: 1 mm - 2 mm; the absolute value of the focal length of the fifth lens is: 1 mm - 2 mm; the absolute value of the focal length of the sixth lens is: 1 mm - 2 mm; the absolute value of the focal length of the doublet lens is: 50 mm - 100 mm.

4. A digestive tract objective lens according to claim 1, characterized in that: The first lens, the second lens, the third lens, the aperture stop, the fourth lens, the fifth lens, and the sixth lens are all spherical lenses made of glass materials.

5. A digestive tract objective lens according to claim 1, characterized in that: The overall optical length after the combination of the front group system and the rear group system is the same.

6. A digestive tract objective lens according to claim 1, characterized in that: The effective focal length f1 of the gastroscope front group system and the effective focal length f2 of the colonoscope front group system satisfy: 0.5 < f1 / f2 < 2; the effective focal length f1 of the gastroscope front group system and the effective focal length f0 of the rear group system satisfy: 0.5 < f1 / f0 < 2; the effective focal length f2 of the colonoscope front group system and the effective focal length f0 of the rear group system satisfy: 0.5 < f2 / f0 < 2.

7. A digestive tract objective lens according to claim 1, characterized in that: The combination of the gastroscope front group system and the rear group system forms a gastroscope system with a FOV of 130° - 150°; the combination of the colonoscope front group system and the rear group system forms a colonoscope system with a FOV of 160° - 180°.

8. A digestive tract objective lens according to claim 1, characterized in that: The dispersion coefficient of the fifth lens is between: 50 - 70; the dispersion coefficient of the sixth lens is between: 10 - 30.

9. A digestive tract objective lens according to claim 1, characterized in that: The thermal expansion coefficients of the fifth lens and the sixth lens are between 6 PPM / K - 9 PPM / K.

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