Ultra-wide-angle capsule endoscope lens

Abstract

An ultra-wide-angle capsule endoscope lens is characterized in that the ultra-wide-angle capsule endoscope lens sequentially comprises a transparent cover (TC), a first lens (L1), a second lens (L2), a third lens (L3), a diaphragm (STO), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6) and a filter (IR) from an object plane to an image plane, and a first lens group (E1) is formed by the first lens (L1), the second lens (L2) and the third lens (L3); the fourth lens (L4), the fifth lens (L5) and the sixth lens (L6) form a second lens group (E2); the lens satisfies the following conditional expressions:-4mmlt; f1-3 / flt; -3 mm; 0.8 mm < lt >; f < 4-6 > / f < lt >; -0.7 mm; 17mm < = TTL / f < = 18mm; the ultra-wide-angle capsule endoscope lens has the advantages of being short in TTL, large in aperture, high in resolution ratio, good in depth of field, large in view field angle and the like.

Description

Technical Field

[0001] This design includes an ultra-wide-angle capsule endoscope lens.

Background Art

[0002] In recent years, capsule endoscopes have developed rapidly in the medical industry. Due to the small viewing range, traditional capsule endoscope lenses have blind spots during examinations and low clarity, and are easily restricted in actual use. Compared with traditional capsule endoscope technology, ultra-wide-angle capsule endoscope lenses have a larger field of view angle, which can make up for the problem of the small field of view of traditional capsule endoscope lenses. However, most of the current ultra-wide-angle capsule endoscope lenses on the market also have problems such as serious lens distortion and large volume. The ultra-wide-angle capsule endoscope lens of this design has characteristics such as short TTL, large aperture, high resolution, and good depth of field, which can not only effectively solve the problems commonly existing in ultra-wide-angle capsule endoscope lenses, but also make up for the deficiencies of traditional ultra-wide-angle capsule endoscope lenses.

Summary of the Invention

[0003] This design provides an ultra-wide-angle capsule endoscope lens, which has a smaller volume while ensuring a larger field of view angle, and also has characteristics such as short TTL, large aperture, high resolution, good depth of field, and high cost performance.

[0004] This design is achieved through the following technical solutions:

[0005] An ultra-wide-angle capsule endoscope lens, characterized in that it sequentially includes a transparent cover (TC), a first lens (L1), a second lens (L2), a third lens (L3), a diaphragm (STO), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), and a filter (IR) from the object plane to the image plane. The first lens group (E1) is composed of the first lens (L1), the second lens (L2), and the third lens (L3), and the second lens group (E2) is composed of the fourth lens (L4), the fifth lens (L5), and the sixth lens (L6);

[0006] The first lens (L1), the second lens (L2), the third lens (L3), and the sixth lens (L6) are all lenses with negative optical power; the fourth lens (L4) and the fifth lens (L5) are all lenses with positive optical power; the rear surface of the fifth lens (L5) and the front surface of the sixth lens (L6) are glued to each other.

[0007] According to the ultra-wide-angle capsule endoscope lens described in claim 1, characterized in that the relationship between the length TTL of the lens and the effective focal length f of the lens is:

[0008] 17mm ≤ TTL / f ≤ 18mm.

[0009] The ultra-wide-angle capsule endoscope lens according to claim 1, wherein: the total length TTL of the lens is:

[0010] TTL ≤ 9 mm.

[0011] The ultra-wide-angle capsule endoscope lens according to claim 1, wherein:

[0012] 4 < FNO < 5;

[0013] FOV > 115°;

[0014] wherein, FNO is the F-number of the lens, and FOV is the maximum half field of view angle of the lens.

[0015] The effective focal length f of the ultra-wide-angle capsule endoscope lens according to claim 1 and its maximum half field of view angle FOV satisfy:

[0016] -2 mm < f × tan(FOV) < -1 mm.

[0017] The overall optical length TTL of the ultra-wide-angle capsule endoscope lens according to claim 1 and the image height IH corresponding to its maximum half field of view angle satisfy:

[0018] 8 mm < TTL / IH < 9 mm.

[0019] The ultra-wide-angle capsule endoscope lens according to claim 1, wherein the maximum half field of view angle FOV of the ultra-wide-angle capsule endoscope lens, the image height IH corresponding to the maximum half field of view angle of the ultra-wide-angle capsule endoscope lens, and the effective focal length f of the ultra-wide-angle capsule endoscope lens satisfy:

[0020] 230° < FOV × IH / f < 250°.

[0021] The ultra-wide-angle capsule endoscope lens according to claim 1, and the lens satisfies the following relational expressions:

[0022] -7 mm < f1 / f < -6 mm;

[0023] -3 mm < f2 / f < -2 mm;

[0024] -3 mm < f3 / f < -2 mm;

[0025] 1 mm < f4 / f < 2 mm;

[0026] -4 mm < f5-6 / f < -3 mm;

[0027] 0.45 mm < f < 0.55 mm;

[0028] 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, f5-6 is the effective focal length of the cemented lens formed by cementing the fifth lens and the sixth lens, and f is the effective focal length of this lens.

[0029] Compared with the prior art, this design has the following advantages:

[0030] 1) The TTL of the ultra-wide-angle capsule endoscope lens in this design is short, which is beneficial to reducing the volume of the lens;

[0031] 2) The F-number of the ultra-wide-angle capsule endoscope lens in this design is large, and the maximum field of view angle is greater than 230°, making the visible range of this lens larger and the resolution higher;

[0032] 3) The image distortion of the ultra-wide-angle capsule endoscope lens in this design is low, and the image distortion is relatively small. It can effectively ensure the resolution and clarity of the captured image while ensuring a large field of view angle;

[0033] 4) The effective focal length of the ultra-wide-angle capsule endoscope lens in this design is small, and the axial distance between each lens group is small, which is beneficial to the depth of field of the lens.

Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of the overall ultra-wide-angle capsule endoscope lens.

[0035] Figure 2 It is the vertical chromatic aberration diagram (mm) of the ultra-wide-angle capsule endoscope lens.

[0036] Figure 3 It is the field curvature distortion diagram (%) of the ultra-wide-angle capsule endoscope lens.

[0037] Figure 4 It is the diffraction MTF diagram of the ultra-wide-angle capsule endoscope lens.

Specific Embodiments

[0038] The following content is the specific embodiments of this design.

[0039] An ultra-wide-angle capsule endoscope lens, characterized in that it sequentially includes a transparent cover (TC), a first lens (L1), a second lens (L2), a third lens (L3), a diaphragm (STO), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), and a filter (IR) from the object plane to the image plane. The first lens group (E1) is composed of the first lens (L1), the second lens (L2) and the third lens (L3), and the second lens group (E2) is composed of the fourth lens (L4), the fifth lens (L5) and the sixth lens (L6);

[0040] The first lens (L1), the second lens (L2), the third lens (L3), and the sixth lens (L6) are all negative-powered lenses; the fourth lens (L4) and the fifth lens (L5) are both positive-powered lenses; the rear surface of the fifth lens (L5) is adhesively bonded to the front surface of the sixth lens (L6).

[0041] In some embodiments, the effective focal length f of the ultra-wide-angle capsule endoscope lens and its maximum half field of view angle FOV satisfy:

[0042] -2mm < f × tan(FOV) < -1mm;

[0043] Satisfying the above conditional formula, by reasonably restricting the field of view angle and focal length of the optical lens, it is beneficial to achieve the balance between the large field of view angle and large target surface imaging of the lens.

[0044] In some embodiments, for the ultra-wide-angle capsule endoscope lens, characterized in that the maximum half field of view angle FOV of the ultra-wide-angle capsule endoscope lens, the image height IH corresponding to the maximum half field of view angle of the ultra-wide-angle capsule endoscope lens, and the effective focal length f of the ultra-wide-angle capsule endoscope lens satisfy:

[0045] 230° < FOV × IH / f < 250°;

[0046] Satisfying the above conditional formula, by reasonably restricting the relationship between the focal length, field of view angle, and image height of the lens, large target surface imaging can be achieved when the lens takes large-angle shots.

[0047] In some embodiments, the overall optical length TTL of the ultra-wide-angle capsule endoscope lens and the image height IH corresponding to its maximum half field of view angle satisfy:

[0048] 8mm < TTL / IH < 9mm;

[0049] Satisfying the above conditional formula, by reasonably restricting the ratio of the overall optical length of the lens to the image height, large target surface imaging can be achieved while shortening the overall optical length, realizing the balance between the miniaturization of the lens and large target surface imaging, and improving the market competitiveness.

[0050] For the above conditions, restricting the second lens group to have positive optical power is mainly used to converge the light rays passing through the first lens group onto the image plane to balance the aberration. When |f2| / f is greater than the upper limit of 2, it will increase the high-order aberration of the system and affect the imaging quality; when |f2| / f is less than the lower limit of 3, it is difficult to correct the system distortion, and the light brightness of the peripheral image of the imaging decreases.

[0051] Let the focal lengths of the first lens (L1), the second lens (L2), the third lens (L3), and the fourth lens (L4) be represented as f1, f2, f3, and f4 respectively, and the focal length of the cemented lens formed by cementing the fifth lens (L5) and the sixth lens (L6) be represented as f5-6. If the effective focal length of this lens is f, the ranges of each focal length value should also satisfy:

[0052] 1) -7mm < f1 / f < -6mm;

[0053] 2) -3mm < f2 / f < -2mm;

[0054] 3) -3mm < f3 / f < -2mm;

[0055] 4) 1mm < f4 / f < 2mm;

[0056] 5) -4mm < f5-6 / f < -3mm;

[0057] 6) 0.45mm < f < 0.55mm;

[0058] The aperture stop of the optical system is located between the first lens group and the second lens group to limit the light flux passing through the first lens group and entering the second lens group optically. A filter (IR) is provided between the cemented lens formed by cementing the fifth lens (L5) and the sixth lens (L6) and the image plane, which can filter out stray light outside the designed wavelength band to achieve the best imaging effect.

[0059] The first lens (L1), the second lens (L2), and the sixth lens (L6) are all spherical lenses; the third lens (L3), the fourth lens (L4), and the fifth lens (L5) are all aspherical lenses.

[0060] The relationship between the length TTL of the ultra-wide-angle capsule endoscope lens and the effective focal length f of this lens is: 17mm ≤ TTL / f ≤ 18mm.

[0061] The length of the ultra-wide-angle capsule endoscope lens satisfies:

[0062] TTL ≤ 9mm.

[0063] The following table is the lens data table of the embodiment:

[0064] Table 1 Structural parameter table of an ultra-wide-angle capsule endoscope lens

[0065]

[0066] Table 2 Aspherical lens surface coefficient table of an ultra-wide-angle capsule endoscope lens

[0067]

[0068]

[0069]

[0070] The above content is only the optimal implementation case of the design content and is not used to limit the design content. Any modified content within the design and its principles should be included in the protection scope of the design.

Claims

1. An ultra-wide-angle capsule endoscope lens, characterized in that: The optical system includes, from the object plane to the image plane, a transparent cover (TC), a first lens (L1), a second lens (L2), a third lens (L3), a stop (STO), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), and a filter (IR); the first lens (L1), the second lens (L2) and the third lens (L3) form a first lens group (E1); the fourth lens (L4), the fifth lens (L5) and the sixth lens (L6) form a second lens group (E2); The first lens (L1), the second lens (L2), the third lens (L3), and the sixth lens (L6) are all lenses with negative optical power; the fourth lens (L4) and the fifth lens (L5) are all lenses with positive optical power; and the rear surface of the fifth lens (L5) and the front surface of the sixth lens (L6) are glued to each other.

2. The ultra-wide-angle capsule endoscope lens according to claim 1, characterized in that: The relationship between the length TTL of the lens and the effective focal length f of the lens is: 17mm≤TTL / f≤18mm.

3. The ultra-wide-angle capsule endoscope lens according to claim 1, characterized in that: The length of this lens TTL: TTL≤9mm.

4. The ultra-wide-angle capsule endoscope lens according to claim 1, characterized in that: 4<FNO<5; FOV>115°; Among them, FNO is the F number of the lens, and FOV is the maximum half field of view angle of the lens.

5. The effective focal length f of the ultra-wide-angle capsule endoscope lens according to claim 1 and its maximum half field of view FOV satisfy: -2mm<f×tan(FOV)<-1mm.

6. The total optical length TTL of the ultra-wide-angle capsule endoscope lens according to claim 1 and the image height IH corresponding to its maximum half-viewing angle satisfy: 8mm<TTL / IH<9mm.

7. The ultra-wide-angle capsule endoscope lens according to claim 1, characterized in that: The maximum half field of view FOV of the ultra-wide-angle capsule endoscope lens, the image height IH corresponding to the maximum half field of view of the ultra-wide-angle capsule endoscope lens, and the effective focal length f of the ultra-wide-angle capsule endoscope lens satisfy: 230°<FOV×IH / f<250°.

8. The ultra-wide-angle capsule endoscope lens according to claim 1 satisfies the following relationship: -7mm<f1 / f<-6mm; -3mm<f2 / f<-2mm; -3mm<f3 / f<-2mm; 1mm<f4 / f<2mm; -4mm<f5-6 / f<-3mm; 0.45mm<f<0.55mm; in, 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, f5-6 is the effective focal length of the cemented lens formed by the fifth lens and the sixth lens, and f is the effective focal length of the lens.

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