Lens assembly, capsule endoscope and system thereof

Abstract

The utility model discloses a lens assembly, a capsule endoscope and a system thereof. The lens assembly is sequentially provided with a first lens, a second lens, a diaphragm, a third lens and a fourth lens at intervals from an object side to an image side, each lens in the lens assembly is an aspherical mirror and is provided with an object side face facing the object side and an image side face facing the image side. The first lens element with negative refractive power has an object-side surface being convex in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof. The second lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof. The third lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof. The fourth lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof, and the lens element provided by the present application has a large field angle.

Description

Technical Field

[0001] The utility model relates to the technical field of medical equipment, and in particular to a lens assembly, a capsule endoscope and a capsule endoscope system. Background Art

[0002] At present, the examinee can take a capsule endoscope with built-in image acquisition and wireless communication device orally to collect images in the digestive tract. The doctor uses an external instrument to receive the images taken by the capsule endoscope to understand the digestive tract condition of the examinee and make a diagnosis of his condition. Capsule endoscopy has the advantages of convenient examination, no trauma, no wires, no pain, no cross infection, and no impact on the normal work of the patient. It expands the field of view of digestive tract examination and overcomes the defects of traditional insertable endoscopy such as poor tolerance and unsuitability for the elderly, weak and critically ill. It can be used as a preferred method for diagnosing digestive tract diseases, especially small intestinal diseases.

[0003] Of course, it is easy to know from the above that the quality of the gastrointestinal images taken by the capsule endoscope directly affects the effect of the capsule endoscopy. However, in the actual use of the capsule endoscope, such as in the stomach, where there is a large space, the optical imaging system of the capsule endoscope often has a small field of view and a small observation range, which easily forms an observation blind spot, leading to problems such as difficulty in image splicing, difficulty in accurately locating the lesion site, and incomplete diagnosis. Utility Model Content

[0004] In order to solve the above technical problems existing in the prior art, the utility model provides a lens assembly, a capsule endoscope and a capsule endoscope system.

[0005] In a first aspect, the present application provides a lens assembly, which comprises: a first lens, a second lens, an aperture, a third lens, and a fourth lens, which are sequentially arranged from the object side to the image side; each lens in the lens assembly is an aspherical lens, and has an object side surface facing the object side and an image side surface facing the image side;

[0006] The first lens has negative refractive power, the object side surface of the first lens is convex at the near optical axis, and the image side surface of the first lens is concave at the near optical axis;

[0007] The second lens has positive refractive power, and its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis;

[0008] The third lens has positive refractive power, and its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis;

[0009] The fourth lens has positive refractive power, and its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis.

[0010] A second aspect of the present application provides a capsule endoscope, comprising a shell and the lens assembly as described above, wherein the shell forms a receiving space, the lens assembly is received in the receiving space, and the capsule endoscope is used to capture images through the lens assembly.

[0011] A third aspect of the present application provides a capsule endoscope system, comprising:

[0012] A capsule endoscope as described above; and

[0013] The terminal is used to receive and display the images taken by the capsule endoscope.

[0014] In the lens assembly provided by the present application, the first lens adopts a negative refractive power configuration, the object side surface of the first lens is convex at the near optical axis, and the image side surface is concave at the near optical axis, which is beneficial to expanding the field of view angle of the lens assembly; the second lens has positive refractive power, which is used to correct the aberration of the convergent light beam emitted by the first lens; the third lens and the fourth lens both have positive refractive power, and through the reasonable setting of the concave and convex shapes of the lens surfaces and the refractive power matching between the lenses, the lens assembly is beneficial to have better light convergence ability and a larger field of view angle.

[0015] Furthermore, in the lens assembly, the image side surface of the first lens is concave at the near optical axis, and the object side surface of the second lens is convex at the near optical axis, so that the image side surface of the first lens and the object side surface of the second lens have a matching concave and convex shape at the near optical axis, which is conducive to the close fit between the first lens and the second lens with a small gap. It is conducive to the design of the two lenses being close to each other, reducing the total optical length of the lens assembly, realizing the miniaturization of the lens assembly, and having a better aberration correction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the embodiments of the present utility model and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present utility model, but do not constitute a limitation on the embodiments of the present utility model.

[0017] Figure 1A A schematic structural diagram of a lens assembly provided in the first embodiment of the present application;

[0018] Figure 1B for Figure 1A Field curvature and distortion curves of the lens assembly shown;

[0019] Figure 1C for Figure 1A Axial aberration curve diagram of the lens assembly shown;

[0020] Figure 1D for Figure 1A Vertical axis chromatic aberration curve of the lens assembly shown;

[0021] Figure 1E for Figure 1A The polychromatic light diffraction through-focus MTF curve of the lens assembly shown;

[0022] Figure 1F for Figure 1A Relative illumination graph of the lens assembly shown;

[0023] Figure 1G To include Figure 1A A schematic structural diagram of a capsule endoscope with a lens assembly and a capsule endoscope system shown;

[0024] Figure 2A A schematic structural diagram of a lens assembly provided in a second embodiment of the present application;

[0025] Figure 2B for Figure 2A Field curvature and distortion curves of the lens assembly shown;

[0026] Figure 2C for Figure 2A Axial aberration curve diagram of the lens assembly shown;

[0027] Figure 2D for Figure 2A A vertical axis chromatic aberration curve diagram of the lens assembly shown;

[0028] Figure 2E for Figure 2A The polychromatic light diffraction through-focus MTF curve of the lens assembly shown;

[0029] Figure 2F for Figure 2A Relative illumination graph of the lens assembly shown;

[0030] Figure 3A A schematic structural diagram of a lens assembly provided in a third embodiment of the present application;

[0031] Figure 3B for Figure 3A Field curvature and distortion curves of the lens assembly shown;

[0032] Figure 3C for Figure 3A Axial aberration curve diagram of the lens assembly shown;

[0033] Figure 3D for Figure 3A A vertical axis chromatic aberration curve diagram of the lens assembly shown;

[0034] Figure 3E for Figure 3A The polychromatic light diffraction through-focus MTF curve of the lens assembly shown;

[0035] Figure 3F for Figure 3A Relative illumination graph of the lens assembly shown. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and implementation methods. It should be understood that the specific implementation methods described here are only used to explain the utility model and are not used to limit the utility model.

[0037] Definition: The side of an optical component or element facing the subject is called the object side, and the side facing the imaging surface is called the image side.

[0038] ND1: The refractive index of the first lens

[0039] ND2: The refractive index of the second lens

[0040] ND3: The refractive index of the third lens

[0041] ND4: The refractive index of the fourth lens

[0042] Vd2: Abbe number of the second lens

[0043] T12: The distance between the first lens and the aperture on the optical axis

[0044] T45: The distance between the third lens and the fourth lens on the optical axis

[0045] f: focal length of the lens assembly

[0046] ENPD: Entrance pupil diameter

[0047] WFno: Lens component F number

[0048] Fov: The field of view of the lens assembly

[0049] RI: Relative Illumination of the Lens Assembly

[0050] k: cone coefficient

[0051] A4: The 4th order coefficient of the aspheric surface

[0052] A6: The sixth-order coefficient of the aspheric surface

[0053] A8: 8th order coefficient of aspheric surface

[0054] A10: The 10th-order coefficient of the aspheric surface

[0055] A12: 12th order coefficient of aspheric surface

[0056] A14: 14th order coefficient of aspheric surface

[0057] A16: 16th order coefficient of aspheric surface

[0058] The present application provides a lens assembly with a large field of view for optical imaging, which can be applied to multi-field products requiring lens assemblies with a large field of view, such as smart terminals, medical examination and surgical systems, industrial cameras, security monitoring equipment, wearable devices, drones, virtual reality (VR) and augmented reality (AR) devices, etc. In the present application, the application of the lens assembly to a capsule endoscope system in the medical field is used as an example for explanation. It can be understood that the lens assembly provided by the present application can also be used in the above-mentioned or unmentioned devices or equipment, which is not limited here.

[0059] The lens assembly provided by this application, such as Figure 1A The lens assembly 100, Figure 2A The lens assembly 200, and Figure 3A The lens assembly 300 in the figure. The lens assembly has an imaging surface IM, which is located on the right side in the corresponding figure, that is, the right side in the figure is the image side, and the left side in the figure is the object side. Correspondingly, the surface of the optical element in the lens assembly facing the right side is the image side surface, and the surface of the optical element in the lens assembly facing the left side is the object side surface.

[0060] The lens assembly is provided with a first lens L1, a second lens L2, an aperture ST, a third lens L3 and a fourth lens L4 in sequence from the object side to the image side. Each lens in the lens assembly is an aspherical lens, and each lens has an object side surface facing the object side and an image side surface facing the image side.

[0061] The first lens L1 has negative refractive power, its object side surface is convex at the near optical axis, and its image side surface is concave at the near optical axis; the second lens L2 has positive refractive power, its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis; the third lens L3 has positive refractive power, its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis; the fourth lens L4 has positive refractive power, its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis.

[0062] In the lens assembly provided in the present application, the first lens L1 adopts a negative refractive power configuration, the object side surface of the first lens L1 is convex at the near optical axis, and the image side surface is concave at the near optical axis, which is beneficial to expanding the field of view angle of the lens assembly; the second lens L2 has a positive refractive power, which is used to correct the aberration of the convergent light beam emitted by the first lens L1; the third lens L3 and the fourth lens L4 both have positive refractive power, and through the reasonable setting of the concave and convex shapes of the lens surfaces and the refractive power matching between the lenses, the lens assembly is beneficial to have better light convergence ability and a larger field of view angle.

[0063] Furthermore, in the lens assembly, the image side surface of the first lens L1 is concave at the near optical axis, and the object side surface of the second lens L2 is convex at the near optical axis, so that the image side surface of the first lens L1 and the object side surface of the second lens L2 have a matching concave and convex shape at the near optical axis, which is conducive to the close fit between the first lens L1 and the second lens L2 with a small gap. It is conducive to the design of the two lenses being close to each other, reducing the total optical length of the lens assembly, realizing the miniaturization of the lens assembly, and having a better aberration correction effect.

[0064] In some embodiments, the first lens L1 and the second lens L2 are nested with each other, for example, the object-side surface of the second lens L2 is disposed in a concave space formed by the image-side surface of the first lens L1.

[0065] The object side surface of the lens described in the utility model is a convex surface, which means that when a section is made through any point on the surface of the lens object side surface, the object side surface is always on the right side of the section surface, and its radius of curvature is positive, otherwise the object side surface is a concave surface, and its radius of curvature is negative. The image side surface is a convex surface, which means that when a section is made through any point on the surface of the lens image side surface, the image side surface is always on the left side of the section surface, and its radius of curvature is negative, otherwise the image side surface is a concave surface, and its radius of curvature is positive. If a section is made through any point on the surface of the lens object side surface or image side surface, the surface has both a part on the left side of the section surface and a part on the right side of the section surface, then the surface has a curve inflection point, and the judgment of the concavity and convexity of the object side surface and the image side surface at the near optical axis still applies to the above.

[0066] The above defines the concavo-convex shapes of the object-side surface and the image-side surface at the near optical axis of each lens. It can be understood that the object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 can have a plurality of inflection points. The inflection point is a point located on the lens surface, and the tangent line of the point is perpendicular to the optical axis.

[0067] The lens assembly includes a filter G disposed between the fourth lens L4 and the imaging surface IM, and specifically, the filter G is an infrared filter. It is understandable that the filter G can be disposed at any position of the lens assembly 100 as required.

[0068] Preferably, the lens assembly satisfies the following conditions: ND1≥1.8, ND2=1.497, ND3=ND4=1.544.

[0069] Among them, ND1 is the refractive index of the first lens L1, ND2 is the refractive index of the second lens L2, ND3 is the refractive index of the third lens L3, and ND4 is the refractive index of the fourth lens L47. Controlling the refractive index is conducive to maintaining good imaging quality. The higher the refractive index of the first lens L1, the more conducive it is to deflect large-angle light into the optical system. The first lens L1 uses a high-refractive material to further increase the deflection ability of light and further improve the field of view of the lens assembly.

[0070] The lens assembly satisfies the following conditions: 1.198≦R12 / R21≦1.42, where R12 is the curvature radius of the image side surface of the first lens L1, and R21 is the curvature radius of the object side surface of the second lens L2. By controlling the curvature of the image side surface of the first lens L1 and the object side surface of the second lens L2, the field of view is further expanded.

[0071] Preferably, the first lens L1 and the second lens L2 are both made of glass.

[0072] In some embodiments, the second lens L2 is made of glass with a low refractive index and a high Abbe number, which can effectively correct the aberration generated by the first lens L1. Optionally, the second lens L2 satisfies:

[0073] Vd2=81.59, where Vd2 is the dispersion coefficient of the second lens L2.

[0074] Preferably, 0.215 mm ≤ T12 ≤ 1.242 mm, wherein T12 is the distance between the first lens and the second lens on the optical axis. The spacing between the first lens L1 and the second lens L2 is limited. When the spacing is small, a better MTF curve can be obtained, and the overall length of the lens assembly can be reduced.

[0075] Preferably, 0.02565 mm ≤ T45 ≤ 0.044 mm, where T45 is the distance between the third lens L3 and the fourth lens L4 on the optical axis. Controlling the distance between the third lens and the fourth lens is conducive to a compact structure between the two, further reducing the length of the lens assembly.

[0076] Preferably, f / ENPD=3, wherein f is the focal length of the lens assembly, and ENPD is the entrance pupil diameter of the lens assembly. By controlling the ratio of the focal length of the lens assembly to the entrance pupil diameter, the aperture is enlarged, the amount of light passing is increased, and the relative illumination of the entire lens assembly is controlled to achieve RI (relative illumination) greater than 75%.

[0077] Preferably, any two adjacent lenses in the lens assembly do not move relative to each other. That is, there is no relative movement between the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 in the lens assembly. In some embodiments, at least one lens in the lens assembly can move relative to other optical elements.

[0078] The present application makes the entire lens assembly have better light convergence ability and larger field of view by reasonably designing the concave-convex surface structure of the lens, matching the refractive power and selecting the material parameters. The following three embodiments specifically illustrate the lens assembly parameters, capsule endoscope 10 and capsule endoscope system 11 provided by the present application.

[0079] First embodiment

[0080] See also Figure 1A The first embodiment of the present application provides a lens assembly 100 for optical imaging. The lens assembly 100 has an imaging surface IM. Figure 1A As shown, the imaging surface IM is located on the right side in the figure, that is, the right side in the figure is the image side, and the left side in the figure is the object side. Correspondingly, the surface of the optical element in the lens assembly 100 facing the right side is the image side, and the surface of the optical element in the lens assembly 100 facing the left side is the object side.

[0081] like Figure 1A As shown, the lens assembly 100 is provided with a first lens L1, a second lens L2, an aperture ST, a third lens L3 and a fourth lens L4 in sequence from the object side to the image side, and each lens has an object side surface facing the object side and an image side surface facing the image side. In this embodiment, the field of view of the lens assembly 100 can reach 170°.

[0082] The lens assembly 100 includes a filter G disposed between the fourth lens L4 and the imaging surface IM, and specifically, the filter G is an infrared filter. It is understandable that the lens assembly 100 can be provided with various types of filters G at any position as required.

[0083] The optical parameters of the element in this embodiment are exemplified below.

[0084] Table 1.1 Optical parameters of the components in the lens assembly provided in the first embodiment of the present application

[0085]

[0086]

[0087] The aspheric curve equation of each lens is expressed as follows:

[0088]

[0089] Among them, Z is the distance vector height from the origin of the aspherical surface when the aspherical surface is at a height r along the optical axis direction, c is the paraxial curvature of the aspherical surface (the radius of curvature R = 1 / c, which is the inverse of the curvature); k is the cone coefficient; Ai is the i-th order coefficient of the aspherical surface, and the high-order coefficients used in the present utility model are A4, A6, A8, A10, A12, A14 and A16.

[0090] Table 1.2 Aspheric coefficients of each lens in the lens assembly provided in the first embodiment of the present application

[0091]

[0092] Table 1.3 Optical parameters satisfied by the lens assembly provided in the first embodiment of the present application

[0093] Optical parameters Numeric f / ENPD 3.00 R12 / R21 1.198

[0094] Second embodiment

[0095] See also Figure 2A The second embodiment of the present application provides a lens assembly 200 for optical imaging. The lens assembly 200 has an imaging surface IM. Figure 2A As shown, the imaging surface IM is located on the right side in the figure, that is, the right side in the figure is the image side, and the left side in the figure is the object side. Correspondingly, the surface of the optical element in the lens assembly 200 facing the right side is the image side, and the surface of the optical element in the lens assembly 200 facing the left side is the object side.

[0096] like Figure 2A As shown, the lens assembly 200 is provided with a first lens L1, a second lens L2, an aperture ST, a third lens L3 and a fourth lens L4 in sequence from the object side to the image side, and each lens has an object side surface facing the object side and an image side surface facing the image side. In this embodiment, the field of view of the lens assembly 200 can reach 170°.

[0097] The lens assembly 200 includes a filter G disposed between the fourth lens L4 and the imaging surface IM, and specifically, the filter G is an infrared filter. It is understandable that the lens assembly 200 can be provided with various types of filters G at any position as required.

[0098] The difference between the lens assembly 200 provided in the second embodiment and the lens assembly 100 provided in the first embodiment lies at least in the following optical parameters of the components.

[0099] The optical parameters of the element in this embodiment are exemplified below.

[0100] Table 2.1 Optical parameters of components in the lens assembly provided in the second embodiment of the present application

[0101]

[0102]

[0103] Table 2.2 Aspheric coefficients of each lens in the lens assembly provided in the second embodiment of the present application

[0104]

[0105] Table 2.3 Optical parameters satisfied by the lens assembly provided in the second embodiment of the present application

[0106] Optical parameters Numeric f / ENPD 3.00 R12 / R21 1.42

[0107] Third embodiment

[0108] See also Figure 3A The third embodiment of the present application provides a lens assembly 300 for optical imaging. The lens assembly 300 has an imaging surface IM. Figure 3A As shown, the imaging surface IM is located on the right side in the figure, that is, the right side in the figure is the image side, and the left side in the figure is the object side. Correspondingly, the surface of the optical element in the lens assembly 300 facing the right side is the image side, and the surface of the optical element in the lens assembly 300 facing the left side is the object side.

[0109] like Figure 3A As shown, the lens assembly 300 is provided with a first lens L1, a second lens L2, an aperture ST, a third lens L3 and a fourth lens L4 in sequence from the object side to the image side, and each lens has an object side surface facing the object side and an image side surface facing the image side. In this embodiment, the field of view of the lens assembly 100 can reach 164°.

[0110] The lens assembly 300 includes a filter G disposed between the fourth lens L4 and the imaging surface IM, and specifically, the filter G is an infrared filter. It is understandable that the lens assembly 300 can be provided with various types of filters G at any position as required.

[0111] The difference between the lens assembly 300 provided in the third embodiment and the lens assembly 100 and the lens assembly 200 provided in the aforementioned embodiments lies at least in the optical parameters of the following components.

[0112] The optical parameters of the element in this embodiment are exemplified below.

[0113] Table 3.1 Optical parameters of components in the lens assembly provided in the third embodiment of the present application

[0114]

[0115] Table 3.2 Aspheric coefficients of each lens in the lens assembly provided in the third embodiment of the present application

[0116]

[0117] Table 3.3 Optical parameters satisfied by the lens assembly provided in the third embodiment of the present application

[0118] Optical parameters Numeric f / ENPD 3.00 R12 / R21 1.36

[0119] For the sake of clarity, the performance curves of the lens assembly provided in this application are all in color, which will be described in detail below.

[0120] Figure 1B , Figure 2B as well as Figure 3BThey are respectively the field curvature curve diagram and the distortion curve diagram corresponding to the lens assembly provided in the first embodiment, the second embodiment and the third embodiment.

[0121] Figure 1B , Figure 2B as well as Figure 3B The figure on the left shows a field curvature curve of the lens assembly of the corresponding embodiment. The field curvature curve represents the field curvature of the image plane at different image heights in the meridian direction and the sagittal direction. The horizontal axis in the figure represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the lens assembly has a large field angle, which is ≥164°. The field curvature offset in the meridian direction and the sagittal direction on the image plane is controlled within ±0.04mm, indicating that the field curvature correction of the optical lens is good.

[0122] Figure 1B , Figure 2B and Figure 3B The figure on the right side shows the distortion curve of the lens assembly of the corresponding embodiment. The optical distortion curve represents the distortion corresponding to different image heights on the image plane. The horizontal axis in the figure represents the distortion size (unit: %), and the vertical axis represents the half field of view angle (unit: °).

[0123] Figure 1C , Figure 2C as well as Figure 3C The axial aberration curves of the lens assembly provided in the first embodiment, the second embodiment and the third embodiment are respectively shown. The axial aberration curve represents the aberration on the optical axis at the imaging surface IM, and the abscissa in the figure represents the offset (unit: mm), and the ordinate represents the pupil radius. It can be seen from the figure that the chromatic aberration offset of the central wavelength at the zero pupil position is controlled within ±0.025mm, and the axial aberration of the shortest wavelength and the maximum wavelength is controlled within ±0.02mm, indicating that the axial aberration of the lens assembly is well corrected.

[0124] Figure 1D , Figure 2D as well as Figure 3D The vertical axis chromatic aberration curves of the lens assembly provided by the first embodiment, the second embodiment and the third embodiment are respectively shown. The vertical axis chromatic aberration curve represents the chromatic aberration of each wavelength at different image heights on the image plane. The horizontal axis in the figure represents the offset (unit: μm), and the vertical axis represents the field angle. It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±3μm, indicating that the lens assembly can well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0125] Figure 1E , Figure 2E as well as Figure 3EThe polychromatic light diffraction defocus MTF curves of the lens assembly provided by the first embodiment, the second embodiment and the third embodiment in the 0.47-0.65 μm band are respectively shown. It can be seen from the figure that the lens assembly can achieve good imaging quality.

[0126] Figure 1F , Figure 2F as well as Figure 3F Relative illumination curves of the lens assemblies provided in the first embodiment, the second embodiment, and the third embodiment are shown respectively. Among them, relative illumination refers to the ratio of the illumination of different coordinate points on the image plane to the illumination of the center point, the ordinate represents the normalized illumination value, and the abscissa represents the field of view angle of the lens. Under the same conditions, a smooth transition of the relative illumination curves of each field of view represents uniform illumination in the imaged image, and the closer the relative illumination value of each field of view is to 1, the higher the final imaging brightness. As shown in the figure, in the three embodiments, the relative illumination of the lens assembly at each position within the field of view angle range of 160°-170° is above 75%, which indicates that the lens assembly has a high uniformity of image plane illumination, and it can also be inferred that the lens assembly has the characteristics of high efficiency and high brightness.

[0127] It can be seen from the above curve graph that the lens assembly provided in each embodiment can achieve a larger field of view and good imaging quality.

[0128] See also Figure 1G The lens assembly 100 provided in the embodiment of the present application can be applied to the capsule endoscope 10 and the capsule endoscope system 11. It can be understood that the lens assembly 200 and the lens assembly 300 provided in other embodiments of the present application can also replace the lens assembly 100 and be applied to the capsule endoscope 10 and the capsule endoscope system 11 provided in the present application, which will not be described in detail below.

[0129] The capsule endoscope 10 comprises a lens assembly 100 and a housing 700, wherein the housing 700 forms a receiving space 701, wherein the lens assembly 100 is received in the receiving space 701, and the capsule endoscope 10 is used to capture images through the lens assembly 100. Preferably, the housing 700 has a transparent portion, and the lens assembly 100 is used to capture images through the transparent portion of the housing 700.

[0130] The capsule endoscope system 11 includes a capsule endoscope 10 and a terminal 90. The capsule endoscope 10 is swallowed by a living being or placed in a living being; the terminal 90 is used to receive and display images captured by the capsule endoscope 10. The terminal 90 can also be used to receive user operation instructions. In some embodiments, the terminal 90 is used to control the capsule endoscope 10 to capture images through the lens assembly 100. In other embodiments, the capsule endoscope 100 can be controlled to capture images in other ways.

[0131] The terminal 90 includes, for example, at least one of a mobile phone, a wearable device, an Internet of Things device, a tablet computer, a computer with wireless transceiver function, a virtual reality terminal device, an augmented reality terminal device, a wireless terminal device in industrial control, and a wireless terminal device in remote surgery, but is not limited thereto.

[0132] For the sake of clarity, Figure 1G The capsule endoscope 10 and the terminal 90 are shown for illustration only and are not drawn in proportion to their actual size.

[0133] The optional implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above implementation modes. Within the technical concept of the present invention, the technical scheme of the present invention can be modified in a variety of simple ways, and these simple modifications all belong to the protection scope of the present invention.

[0134] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the various possible combinations of the embodiments of the present utility model will not be described separately.

[0135] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A lens assembly, characterized in that: The lens assembly is provided with a first lens, a second lens, an aperture, a third lens and a fourth lens in order from the object side to the image side; each lens in the lens assembly is an aspherical lens and has an object side surface facing the object side and an image side surface facing the image side; The first lens has negative refractive power, the object side surface of the first lens is convex at the near optical axis, and the image side surface of the first lens is concave at the near optical axis; The second lens has positive refractive power, and its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis; The third lens has positive refractive power, and its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis; The fourth lens has positive refractive power, and its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis.

2. The lens assembly according to claim 1, wherein: The lens assembly meets the following conditions: ND1≥1.8, ND2=1.497, ND3=ND4=1.544, Wherein, ND1 is the refractive index of the first lens, ND2 is the refractive index of the second lens, ND3 is the refractive index of the third lens, and ND4 is the refractive index of the fourth lens.

3. The lens assembly according to claim 2, characterized in that: The lens assembly meets the following conditions: 1.198≦R12 / R21≦1.42, Wherein, R12 is the curvature radius of the image side surface of the first lens, and R21 is the curvature radius of the object side surface of the second lens.

4. The lens assembly according to claim 2, wherein: The second lens satisfies: Vd2=81.59, Wherein, Vd2 is the dispersion coefficient of the second lens.

5. The lens assembly according to any one of claims 1 to 4, characterized in that: The lens assembly meets the following conditions: 0.215mm≤T12≤1.242mm, Wherein, T12 is the distance between the first lens and the second lens on the optical axis.

6. The lens assembly according to any one of claims 1 to 4, characterized in that: The lens assembly satisfies: 0.02565mm≤T45≤0.044mm, T45 is the distance between the third lens and the fourth lens on the optical axis.

7. The lens assembly according to any one of claims 1 to 4, characterized in that: The lens assembly meets the following conditions: f / ENPD=3; Wherein, f is the focal length of the lens assembly, and ENPD is the entrance pupil diameter of the lens assembly.

8. The lens assembly according to any one of claims 1 to 4, characterized in that: Any two adjacent lenses in the lens assembly do not move relative to each other.

9. A capsule endoscope, characterized in that: It comprises a shell and a lens assembly as described in any one of claims 1 to 8, wherein the shell forms a receiving space, the lens assembly is received in the receiving space, and the capsule endoscope is used to capture images through the lens assembly.

10. A capsule endoscope system, characterized in that: include: The capsule endoscope according to claim 9; as well as The terminal is used to receive and display the images taken by the capsule endoscope.

Images