An ultra-wide angle capsule endoscope lens

Abstract

An ultra-wide-angle capsule endoscope lens is characterized in that, from an object plane to an image plane, 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 an infrared filter (IR) are sequentially arranged, the first lens (L1), the second lens (L2), and the third lens (L3) constitute a first lens group (E1), the fourth lens (L4), the fifth lens (L5), and the sixth lens (L6) constitute a second lens group (E2), and the lens satisfies the following conditional expressions: -4mm < f1-3 / f < -3mm; -0.8mm < f4-6 / f < -0.7mm; and 17mm <= TTL / f <= 18mm. The ultra-wide-angle capsule endoscope lens has the characteristics of a short TTL, a large aperture, high resolution, good depth of field, and a large field of view.

Description

Technical Field

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

[0002] In recent years, capsule endoscopy has developed rapidly in the medical industry. Traditional capsule endoscope lenses, due to their small field of view, suffer from blind spots and low clarity during examinations, limiting their practical use. Compared to traditional capsule endoscopy technology, ultra-wide-angle capsule endoscope lenses offer a wider field of view, compensating for the limited field of view of traditional lenses. However, most ultra-wide-angle capsule endoscope lenses on the market currently suffer from severe lens distortion and large size. This design presents an ultra-wide-angle capsule endoscope lens with short TTL, large aperture, high resolution, and good depth of field, effectively solving the common problems of ultra-wide-angle capsule endoscope lenses while also overcoming the shortcomings of traditional ultra-wide-angle capsule endoscope lenses. Summary of the Invention

[0003] This design provides an ultra-wide-angle capsule endoscope lens that maintains a large field of view while having a smaller size.

[0004] In addition to its compact size, it also features short TTL, large aperture, high resolution, good depth of field, and high cost-effectiveness.

[0005] This design was achieved through the following technical solutions:

[0006] An ultra-wide-angle capsule endoscope lens is characterized in that, from the object plane to the image plane, it comprises a transparent cover (TC), a first lens (L1), a second lens (L2), a third lens (L3), an aperture stop (STO), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), and an IR filter. The first lens (L1), the second lens (L2), and the third lens (L3) constitute a first lens group (E1), and the fourth lens (L4), the fifth lens (L5), and the sixth lens (L6) constitute a second lens group (E2).

[0007] 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 both lenses with positive optical power; the rear surface of the fifth lens (L5) and the front surface of the sixth lens (L6) are bonded together.

[0008] The ultra-wide-angle capsule endoscope lens is characterized in that: the effective focal length f of the lens and its maximum half-field of view (FOV) satisfy the following:

[0009] -2mm < f×tan(FOV) < -1mm.

[0010] The ultra-wide-angle capsule endoscope lens is characterized in that: the maximum half-field-of-view (FOV) of the lens, the image height (IH) corresponding to the maximum half-field-of-view, and the effective focal length (f) of the lens satisfy the following:

[0011] 230° < FOV × IH / f < 250°.

[0012] The ultra-wide-angle capsule endoscope lens is characterized in that: the total optical length TTL of the lens and the image height IH corresponding to its maximum half-field angle satisfy the following:

[0013] 8mm < TTL / IH < 9mm.

[0014] Compared with existing technologies, this design has the following advantages:

[0015] 1) The ultra-wide-angle capsule endoscope lens in this design has a short TTL, which helps to reduce the size of the lens;

[0016] 2) The ultra-wide-angle capsule endoscope lens of this design has a large F-number and a maximum field of view of more than 230°, which makes the lens have a wider field of view and higher resolution;

[0017] 3) The ultra-wide-angle capsule endoscope lens of this design has low image distortion and minimal image loss. While ensuring a large field of view, it can also effectively guarantee the resolution and clarity of the captured images.

[0018] 4) The ultra-wide-angle capsule endoscope lens of this design has a small effective focal length and a small on-axis distance between each lens group, which is beneficial to the depth of field of the lens. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of an ultra-wide-angle capsule endoscope lens.

[0020] Figure 2 This is a transverse chromatic aberration diagram (mm) of an ultra-wide-angle capsule endoscope lens.

[0021] Figure 3 This is a field curvature distortion (%) diagram of an ultra-wide-angle capsule endoscope lens.

[0022] Figure 4 This is a diffraction MTF pattern of an ultra-wide-angle capsule endoscope lens. Detailed Implementation

[0023] The following describes a specific implementation of this design. An ultra-wide-angle capsule endoscope lens, characterized in that, from the object plane to the image plane, it sequentially comprises a transparent cover (TC), a first lens (L1), a second lens (L2), a third lens (L3), an aperture stop (STO), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), and an IR filter. The first lens (L1), the second lens (L2), and the third lens (L3) constitute a first lens group (E1), and the fourth lens (L4), the fifth lens (L5), and the sixth lens (L6) constitute a second lens group (E2).

[0024] 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 both lenses with positive optical power; the rear surface of the fifth lens (L5) and the front surface of the sixth lens (L6) are bonded together.

[0025] In some implementations, the effective focal length f of the ultra-wide-angle capsule endoscope lens and its maximum field of view (FOV) satisfy the following:

[0026] -2mm < f×tan(FOV) < -1mm;

[0027] By satisfying the above conditions and reasonably limiting the field of view and focal length of the optical lens, it is beneficial to achieve a balance between the large field of view and the imaging of a large target surface.

[0028] In some embodiments, the ultra-wide-angle capsule endoscope lens is characterized in that the maximum half-field angle (FOV) of the ultra-wide-angle capsule endoscope lens, the image height (IH) corresponding to the maximum half-field angle of the ultra-wide-angle capsule endoscope lens, and the effective focal length (f) of the ultra-wide-angle capsule endoscope lens satisfy the following:

[0029] 230°<FOV×IH / f<250°; satisfying the above conditions, by reasonably limiting the relationship between the lens's focal length, field of view, and image height, the lens can achieve large target surface imaging when shooting at large angles.

[0030] In some implementations, the total optical length (TTL) of the ultra-wide-angle capsule endoscope lens satisfies the following condition:

[0031] 8mm < TTL / IH < 9mm;

[0032] By satisfying the above conditions and reasonably limiting the ratio of the total optical length to the image height of the lens, it is possible to achieve large target surface imaging while shortening the total optical length, thus achieving a balance between miniaturization and large target surface imaging, and improving market competitiveness.

[0033] For the above conditions, the second lens group is limited to having positive optical power, mainly used to converge the light rays passing through the first lens group onto the image plane to balance aberrations. When |f2| / f is greater than the upper limit of 2, it will increase the higher-order aberrations of the system and the image quality; when |f2| / f is less than the lower limit of 3, the system distortion is difficult to correct, and the brightness of the peripheral image decreases. Let the focal lengths of the first lens (L1), second lens (L2), third lens (L3), and fourth lens (L4) be expressed as f1, f2, f3, and f4 respectively, and the focal length of the cemented lens formed by the fifth lens (L5) and sixth lens (L6) be expressed as f5-6, where f is the effective focal length of the lens. Then, the range of each focal length value must also satisfy:

[0034] 1) -7mm < f1 / f < -6mm;

[0035] 2) -3mm < f2 / f < -2mm;

[0036] 3) -3mm < f3 / f < -2mm;

[0037] 4) 1mm < f4 / f < 2mm;

[0038] 5) -4mm < f5-6 / f < -3mm;

[0039] 6) 0.45mm < f < 0.55mm;

[0040] The aperture stop of the optical system is located between the first and second lens groups to limit the light throughput entering the second lens group after passing through the first lens group. An IR filter is placed between the cemented lens (L5 and L6) and the image plane to filter out stray light outside the designed wavelength range, achieving optimal imaging results. The first lens (L1), second lens (L2), and sixth lens (L6) are all spherical lenses; the third lens (L3), fourth lens (L4), and fifth lens (L5) are all aspherical lenses.

[0041] The relationship between the length TTL of the ultra-wide-angle capsule endoscope lens and the effective focal length f of the lens is as follows:

[0042] 17mm≤TTL / f≤18mm.

[0043] The length of the ultra-wide-angle capsule endoscope lens meets the following requirements:

[0044] TTL≤9mm.

[0045] The following table is a lens data sheet for an example:

[0046] Table 1. Structural parameters of an ultra-wide-angle capsule endoscope lens.

[0047]

[0048] Table 2. Surface coefficient of aspherical lens for an ultra-wide-angle capsule endoscope.

[0049]

[0050]

[0051]

[0052] The above content is only the optimal implementation example of this design and is not intended to limit the content of this design. Any modifications made within the scope of this design and its principles shall be included within the protection scope of this design.

Claims

1. An ultra-wide-angle capsule endoscope lens, characterized in that, From the object plane to the image plane, the lens consists of a transparent cover (TC), a first lens (L1), a second lens (L2), a third lens (L3), an aperture stop (STO), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), and a filter (IR). 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). 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 both lenses with positive optical power; the rear surface of the fifth lens (L5) and the front surface of the sixth lens (L6) are bonded together.

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

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

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

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

6. The ultra-wide angle endoscopy lens according to claim 1, characterized in that: The total optical length TTL of the lens and the image height IH corresponding to its maximum half field of view satisfy the following: 8mm < TTL / IH < 9mm.

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

8. The ultra-wide field capsule endoscope lens of claim 1, wherein: The lens 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; 45mm < f < 0.55mm; Where 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 are the effective focal lengths of the cemented lens formed by the fifth and sixth lenses, and f is the effective focal length of the lens.

Images