CN112014942A

CN112014942A - Lens assembly, image capturing module and medical equipment

Info

Publication number: CN112014942A
Application number: CN201910456586.5A
Authority: CN
Inventors: 谢晗; 刘彬彬; 邹海荣
Original assignee: OFilm Tech Co Ltd
Current assignee: OFilm Group Co Ltd
Priority date: 2019-05-29
Filing date: 2019-05-29
Publication date: 2020-12-01

Abstract

The invention relates to a lens assembly, an image capturing module and medical equipment. The lens assembly sequentially comprises a first lens with negative refractive power from an object side to an image side, and the image side surface of the first lens is a concave surface; a diaphragm; a second lens element with positive refractive power having a convex image-side surface; a third lens element with positive refractive power having a convex object-side surface at an optical axis, a concave object-side surface at a circumference, a concave image-side surface at the optical axis, and a convex image-side surface at the circumference; the lens assembly satisfies the following relationship: FOV (1.0F) is not less than 130 degrees; the lens assembly with the three-piece structure is beneficial to realizing miniaturization design, so that the size of the assembled image capturing module is reduced; when the relation is satisfied, the lens assembly has wide-angle characteristics and can acquire a large-range image.

Description

Lens assembly, image capturing module and medical equipment

Technical Field

The present invention relates to the field of optical imaging, and in particular, to a lens assembly, an image capturing module and a medical device.

Background

In recent years, with the rapid development of the medical field, there has been an increasing demand in society for medical equipment, and in particular, there has been an increasing demand for performance of a camera mounted on medical inspection equipment. For example, in order to enter a human body more flexibly and more comprehensively to acquire images, medical devices such as endoscopes and the like with camera lenses are generally adopted, but cameras in such traditional medical devices are large in size and difficult to acquire large-range images, and cannot meet the requirements of precise medical detection.

Disclosure of Invention

Therefore, it is necessary to provide a lens assembly, an image capturing module and a medical device for the miniaturization and large viewing angle of a camera.

A lens assembly comprises, in order from an object side to an image side:

the lens comprises a first lens element with negative refractive power, a second lens element with negative refractive power and a third lens element with negative refractive power, wherein the image side surface of the first lens element is concave;

a diaphragm;

a second lens element with positive refractive power having a convex image-side surface;

a third lens element with positive refractive power having a convex object-side surface at an optical axis, a concave object-side surface at a circumference, a concave image-side surface at the optical axis, and a convex image-side surface at the circumference;

the lens assembly satisfies the following relationship:

FOV(1.0F)≥130°；

wherein, FOV (1.0F) is the maximum field angle of the lens assembly, i.e. the field angle of the lens assembly corresponding to the image height of 1.0 field of view.

The lens assembly adopting the three-piece structure is beneficial to realizing the miniaturization design, so that the size of the assembled image capturing module can be reduced; in addition, when satisfying above-mentioned relation, the camera lens subassembly possesses wide angle characteristic to can gather large-range image, be convenient for observe object around, and be favorable to accurate detection.

In one embodiment, the lens assembly satisfies the following relationship:

FOV(0.7F)≥100°；

wherein, the FOV (0.7F) is the field angle corresponding to the lens assembly at the image height of 0.7 field of view. When the above relation is satisfied, the lens assembly is favorable for collecting a large-range image, thereby facilitating the observation of surrounding objects.

In one embodiment, the lens assembly satisfies the following relationship:

RI (1.0F) > 50%, wherein RI (1.0F) is the relative illumination of the lens assembly in a 1.0 field of view; alternatively, the relative illumination of all fields of view of the lens assembly is greater than 50%. When the above relation is satisfied, the picture brightness of the lens component during macro shooting can be improved, so that the shot picture is higher in definition, and careful observation of objects is facilitated.

In one embodiment, the lens assembly satisfies the following relationship:

TTL＜4.25；

wherein, TTL is the distance on the optical axis from the object side surface of the first lens to the image surface of the lens component, and the unit of TTL is mm. When the relation is met, the lens assembly has shorter optical length, so that the miniaturization design is facilitated; when the camera lens subassembly is applied to medical equipment, be favorable to reducing medical equipment's size in order to make things convenient for putting into the medical equipment narrow and small internal or space in space, greatly avoid causing the sore to the human body because of medical equipment is bulky, simultaneously, also more be favorable to medical equipment's nimble removal to gather omnidirectional image information.

In one embodiment, the lens assembly satisfies the following relationship:

FNO≤3.0；

wherein FNO is the f-number of the lens assembly. When the above relation is satisfied, the lens assembly has excellent shooting performance, and is favorable for satisfying the characteristic of high relative illumination.

In one embodiment, the lens assembly satisfies the following relationship:

SD1≤1.7；

wherein SD1 is the maximum effective half aperture of the object side surface of the first lens, and SD1 is in mm. When the above relation is satisfied, the miniaturization design of the lens assembly is facilitated.

In one embodiment, the lens assembly satisfies the following relationship:

-1＜f/f1＜0；

wherein f is the total effective focal length of the lens assembly, and f1 is the effective focal length of the first lens. When the above relation is satisfied, the light rays with large visual angles can enter the lens assembly. If the above relationship is lower than the lower limit, it becomes difficult to correct chromatic aberration of the lens unit, and it becomes difficult to obtain a good image.

In one embodiment, the lens assembly satisfies the following relationship:

3＜TTL/BF＜5；

wherein, TTL is a distance on an optical axis from an object side surface of the first lens to an image surface of the lens assembly, and BF is a distance on the optical axis from an image side surface of the third lens to the image surface of the lens assembly. If the relation exceeds the upper limit value, the total length of the lens assembly is lengthened, and the miniaturization design is difficult to realize; in addition, the third lens is likely to be too close to the image plane of the lens assembly, which may result in insufficient space when the lenses of the lens assembly are assembled with components such as a photosensitive element and an optical filter, and may easily cause problems such as color shift, thereby affecting the imaging quality. If the above relationship is lower than the lower limit, the total length of the lens assembly is excessively compressed, the lens thickness is difficult to be reasonably arranged, and the aberration correction is liable to be insufficient.

In one embodiment, the lens assembly satisfies the following relationship:

TTL/ImgH＜2.8；

wherein, TTL is a distance on an optical axis from an object side surface of the first lens to an image plane of the lens assembly, and ImgH is a half of a diagonal length of an effective pixel area of the lens assembly on the image plane. When the above relation is satisfied, the optical total length of the lens assembly can be effectively compressed, and the requirement of miniaturization design is further satisfied.

In one embodiment, the lens assembly satisfies the following relationship:

CT1/ET1＜1.5；

wherein CT1 is the central thickness of the first lens, and ET1 is the thickness of the first lens at the maximum effective aperture of the object side. When the above relationship is satisfied, the thickness ratio of the center thickness to the edge thickness (the thickness at the maximum effective aperture of the object side surface) of the first lens element can be made uniform, which is favorable for processing and molding the first lens element L1.

In one embodiment, the lens assembly satisfies the following relationship:

-20＜Tan[FOV(1.0F)/2]/f1＜-1；

wherein FOV (1.0F) is the maximum field angle of the lens assembly, F1 is the effective focal length of the first lens, and F1 is in mm. When the above relation is satisfied, the effective focal length of the first lens can be reasonably configured, so that the lens assembly has a larger field angle.

An image capturing module includes a photosensitive element and the lens assembly according to any of the above embodiments, wherein the photosensitive element is disposed on an image side of the lens assembly.

A medical apparatus, comprising the image capturing module of the above embodiment.

Drawings

Fig. 1 is a schematic structural diagram of a lens assembly according to a first embodiment of the present application;

fig. 2 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) -of the lens assembly in the first embodiment;

FIG. 3 is a graph showing the variation of the relative illumination of the lens assembly with the image height according to the first embodiment;

fig. 4 is a schematic structural diagram of a lens assembly according to a second embodiment of the present application;

fig. 5 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) -of the lens assembly in the second embodiment;

FIG. 6 is a graph showing the variation of the relative illumination of the lens assembly with the image height according to the second embodiment;

fig. 7 is a schematic structural diagram of a lens assembly according to a third embodiment of the present application;

fig. 8 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) -of the lens assembly in the third embodiment;

FIG. 9 is a graph showing the variation of the relative illumination of the lens assembly with the image height according to the third embodiment;

fig. 10 is a schematic structural diagram of a lens assembly according to a fourth embodiment of the present application;

fig. 11 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) -of the lens assembly in the fourth embodiment;

FIG. 12 is a graph showing the variation of the relative illumination of the lens assembly with the image height according to the fourth embodiment;

fig. 13 is a schematic structural diagram of a lens assembly according to a fifth embodiment of the present application;

fig. 14 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) -of the lens assembly in the fifth embodiment;

fig. 15 is a graph showing the variation of the relative illumination of the lens assembly with the image height according to the fifth embodiment;

fig. 16 is a schematic structural diagram of a lens assembly according to a sixth embodiment of the present application;

fig. 17 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) -of the lens assembly in the sixth embodiment;

fig. 18 is a graph showing the variation of the relative illuminance of the lens assembly with the image height in the sixth embodiment;

fig. 19 is a schematic view of an image capturing module according to an embodiment of the present application;

fig. 20 is a schematic view of a medical device provided in an embodiment of the present application.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, the lens assembly 100 in the present application includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a second lens element L2 with positive refractive power, and a third lens element L3 with positive refractive power. The lens assembly 100 having the three-piece structure is advantageous for miniaturization design, so that the size of the assembled image capturing module can be reduced.

The first lens L1 includes an object-side surface S1 and an image-side surface S2, the second lens L2 includes an object-side surface S3 and an image-side surface S4, and the third lens L3 includes an object-side surface S5 and an image-side surface S6. In addition, the image side of the third lens L3 has an image plane S9, and the image plane S9 may be photosensitive surfaces of the photosensitive elements.

In some embodiments, the lens assembly 100 further includes a stop STO, which may be disposed on the object side of the first lens L1, between the first lens L1 and the second lens L2, or between the second lens L2 and the third lens L3.

For example, light rays carrying subject information can sequentially pass through the first lens L1, the stop STO, the second lens L2, and the third lens L3 and finally form an image on the image plane S9.

The image-side surface S2 of the first lens L1 is concave. The image-side surface S4 of the second lens element L2 is convex. The object-side surface S5 of the third lens element L3 is convex along the optical axis, the object-side surface S5 of the third lens element L3 is concave along the circumference, the image-side surface S6 of the third lens element L3 is concave along the optical axis, and the image-side surface S6 of the third lens element L3 is convex along the circumference.

In some embodiments, the object-side surface S5 and the image-side surface S6 of the third lens element L3 are aspheric, and at least one of the object-side surface S5 and the image-side surface S6 of the third lens element L3 has at least one inflection point. In some embodiments, the object-side and image-side surfaces of the first, second and third lenses L1, L2 and L3 are aspheric. The aspheric surface type formula is:

z is the distance from a corresponding point on the aspheric surface to a plane tangent to the surface vertex, r is the distance from the corresponding point on the aspheric surface to the optical axis, c is the curvature of the aspheric surface vertex, k is a conic constant, and Ai is a coefficient corresponding to the i-th high-order term in the aspheric surface type formula.

In some embodiments, the first lens L1, the second lens L2, and the third lens L3 are all made of plastic, and the plastic lens can reduce the weight of the lens assembly 100 and the production cost. In some embodiments, the first lens L1, the second lens L2, and the third lens L3 are made of glass, and the glass lens can withstand higher temperature and has better optical performance. In other embodiments, only the first lens L1 may be made of glass, and the other lenses may be made of plastic, in which case, the first lens L1 closest to the object side can better withstand the environment temperature at the object side, and the production cost of the lens assembly 100 can also be reduced because the other lenses are made of plastic.

In some embodiments, an infrared filter 110 is further disposed on the image side of the third lens L3, and the infrared filter 110 includes an object side surface S7 and an image side surface S8. In other embodiments, the infrared filter 110 may also be disposed on the object side of the first lens L1. By arranging the infrared filter 110, the lens assembly 100 can filter out infrared light, and prevent the infrared light from reaching the photosensitive element to interfere with normal visible light imaging, thereby improving the imaging quality. It should be noted that, in some embodiments, the lens assembly 100 does not include the infrared filter and the photosensitive element, and at this time, the infrared filter may be disposed in the module when the lens assembly 100 and the photosensitive element are packaged together into the module.

In some embodiments, the lens assembly 100 satisfies the following relationship:

FOV (1.0F) is not less than 130 degrees; wherein, the FOV (1.0F) is the maximum field angle of the lens assembly 100, i.e. the field angle of the lens assembly 100 corresponding to the image height of the 1.0 field of view. In some embodiments, the FOV (1.0F) may be 135 °, 140 °, 145 °, 150 °, 155 °, or 160 °. The lens assembly 100 adopts a three-piece structure, thereby being beneficial to miniaturization design, and also being beneficial to reducing the volume of equipment when being applied to medical equipment (such as an endoscope), thereby effectively avoiding the skin sore of a human body caused by the overlarge volume of the equipment; in addition, when the above relationship is satisfied, the lens assembly 100 has a wide-angle characteristic, so that it is possible to collect a wide range of images, facilitate observation of objects around the device, and facilitate precise detection.

FOV (0.7F) is more than or equal to 100 degrees; wherein, the FOV (0.7F) is the field angle corresponding to the lens assembly 100 at the image height of the 0.7 field of view. In some embodiments, the FOV (0.7F) may be 101 °, 102 °, 103 °, 105 °, or 106 °. Satisfying the above relationship facilitates the lens assembly 100 to capture a wide range of images, thereby facilitating the observation of surrounding objects.

RI (1.0F) > 50%; wherein RI (1.0F) is the relative illumination of the lens assembly 100 in the 1.0 field of view; alternatively, the relative illumination of all fields of view of the lens assembly 100 is greater than 50%. In some embodiments, the RI (1.0F) may be 52%, 54%, 56%, 58%, 60%, or 62%. When the above relationship is satisfied, the brightness of the shot image of the lens assembly 100 during macro shooting can be improved, so that the shot image is more high-definition, and careful observation of the object is facilitated.

TTL is less than 4.25; wherein, TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the image surface S9 of the lens assembly 100, and the unit of TTL is mm. In some embodiments, the TTL can be 3.80, 3.85, 3.90, 4.00, 4.05, 4.10, 4.15, or 4.20. When the above relationship is satisfied, the lens assembly 100 has a shorter optical length, thereby facilitating the realization of a miniaturized design; when lens subassembly 100 is applied to medical equipment, be favorable to reducing medical equipment's size in order to conveniently put into the medical equipment narrow and small internal or the space in space, greatly avoid causing the sore to the human body because of medical equipment is bulky, simultaneously, also more be favorable to medical equipment's nimble removal to gather omnidirectional image information.

FNO is less than or equal to 3.0; wherein, FNO is the lens subassembly 100 f-number. In some embodiments, the FNO may be 2.3, 2.5, 2.6, 2.7, 2.8, or 2.9. When the above relationship is satisfied, the lens assembly 100 has excellent image pickup performance, which is advantageous for satisfying the characteristic of high relative illuminance.

SD1 is less than or equal to 1.7; wherein SD1 is the maximum effective half aperture of the object-side surface S1 of the first lens L1, and SD1 is in mm. In some embodiments, SD1 may be 1.52, 1.54, 1.56, 1.58, 1.60, 1.62, 1.64, 1.66, or 1.68. Satisfying the above relationship is advantageous for the miniaturization design of the lens assembly 100.

-1 < f/f1 < 0; where f is the total effective focal length of the lens assembly 100, and f1 is the effective focal length of the first lens L1. In some embodiments, the relationship of f/f1 may be-0.53, -0.52, -0.51, -0.50, or-0.49. When the above relationship is satisfied, it is advantageous for light rays with a large viewing angle to enter the lens assembly 100. If the above relationship is lower than the lower limit, it becomes difficult to correct chromatic aberration of the lens assembly 100, and it becomes difficult to obtain a good image.

TTL/BF is more than 3 and less than 5; wherein, TTL is an axial distance from the object-side surface S1 of the first lens L1 to the image plane S9 of the lens assembly 100, and BF is an axial distance from the image-side surface S6 of the third lens L3 to the image plane S9 of the lens assembly 100. In some embodiments, the TTL/BF relationship may be 3.35, 3.40, 3.45, 3.50, 3.60, 3.70, 3.80, 3.85, 3.90, or 3.95. If the above relationship exceeds the upper limit, the total length of the lens assembly 100 will become long, and it is difficult to realize a miniaturized design; in addition, the third lens L3 is likely to be too close to the image plane S9 of the lens assembly 100, and thus, when the lenses (the first lens L1, the second lens L2, and the third lens L3) of the lens assembly 100 are assembled with components such as a photosensitive element and a filter, a space is not sufficient, and problems such as color shift are likely to occur, which affects the imaging quality. If the above relationship is lower than the lower limit, the total length of the lens assembly 100 is excessively compressed, the lens thickness is difficult to be reasonably arranged, and the aberration correction is liable to be insufficient.

TTL/ImgH is less than 2.8; wherein, TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the image plane S9 of the lens assembly 100, and ImgH is half the diagonal length of the effective pixel area of the lens assembly 100 on the image plane S9. In some embodiments, the TTL/ImgH relationship may be 2.55, 2.60, 2.65, 2.70, or 2.75. When the above relationship is satisfied, the total optical length of the lens assembly 100 can be effectively compressed, thereby satisfying the requirement of miniaturization design.

CT1/ET1 is less than 1.5; CT1 is the central thickness of the first lens element L1, and ET1 is the thickness of the first lens element L1 at the maximum effective aperture of the object-side surface S1. In some embodiments, the relationship of CT1/ET1 may be 0.89, 0.92, 0.96, 0.99, 1.05, 1.09, or 1.11. When the above relationship is satisfied, the thickness ratio of the center thickness to the edge thickness (the thickness at the maximum effective aperture of the object-side surface S1) of the first lens element L1 can be made uniform, which is favorable for processing and molding the first lens element L1.

-20＜Tan[FOV(1.0F)/2]/f1＜-1；

where FOV (1.0F) is the maximum angle of view of the lens assembly 100, F1 is the effective focal length of the first lens L1, and F1 is in mm. In some embodiments, the Tan [ FOV (1.0F)/2]/F1 relationship can be-3.10, -3.00, -2.00, -1.90, -1.60, -1.40, or-1.30. When the above relationship is satisfied, the effective focal length of the first lens L1 can be configured properly, so that the lens assembly 100 has a large angle of view.

First embodiment

In the first embodiment shown in fig. 1, the lens assembly 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a stop STO, a second lens element L2 with positive refractive power, a third lens element L3 with positive refractive power, and an ir filter 110. In addition, fig. 2 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the lens assembly 100 in the first embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength (see the notation in table 1). Fig. 3 is a graph showing the relative illuminance of the lens assembly 100 according to the first embodiment as a function of the image height, wherein the abscissa is a half image height value, i.e., the origin of coordinates corresponds to the center of the effective pixel area of the image plane S9, the maximum value of the abscissa corresponds to half the length of the diagonal line of the effective pixel area of the image plane S9, and the ordinate is a relative illuminance value.

The object-side surface S1 of the first lens element L1 is concave along the optical axis, and the image-side surface S2 of the first lens element L1 is concave along the optical axis; the object-side surface S1 of the first lens element L1 is convex at the circumference, and the image-side surface S2 of the first lens element L1 is concave at the circumference. The object-side surface S3 of the second lens element L2 is convex along the optical axis, and the image-side surface S4 of the second lens element L2 is convex along the optical axis; the object-side surface S3 of the second lens element L2 is convex at the circumference, and the image-side surface S4 of the second lens element L2 is convex at the circumference. The object-side surface S5 of the third lens element L3 is convex along the optical axis, and the image-side surface S6 of the third lens element L3 is concave along the optical axis; the object-side surface S5 of the third lens element L3 is concave at the circumference, and the image-side surface S6 of the third lens element L3 is convex at the circumference.

The object-side and image-side surfaces of the first lens element L1, the second lens element L2, and the third lens element L3 are aspheric.

The first lens L1, the second lens L2 and the third lens L3 are all made of plastic.

The lens assembly 100 has a three-piece structure, thereby facilitating miniaturization, and reducing the volume of the device when applied to medical devices (such as endoscopes), thereby effectively preventing the body from being sore due to the over-large volume of the device.

Specifically, the lens assembly 100 also satisfies the following relationship:

FOV (1.0F) 135 °; wherein, the FOV (1.0F) is the maximum field angle of the lens assembly 100, i.e. the field angle of the lens assembly 100 corresponding to the image height of the 1.0 field of view. When the above relationship is satisfied, the lens assembly 100 can acquire a wide range of images, which is convenient for observing objects around the device and is beneficial to precise detection.

FOV (0.7F) 100 °; wherein, the FOV (0.7F) is the field angle corresponding to the lens assembly 100 at the image height of the 0.7 field of view. Satisfying the above relationship facilitates the lens assembly 100 to capture a wide range of images, thereby facilitating the observation of surrounding objects.

The relative illumination of all the fields of view of the lens assembly 100 is greater than 50%, where RI (1.0F) ═ 58.4%, RI (1.0F) is the relative illumination of the lens assembly 100 in 1.0 field of view. When the above relationship is satisfied, the brightness of the shot image of the lens assembly 100 during macro shooting can be improved, so that the shot image is more high-definition, and careful observation of the object is facilitated.

TTL is 4.0; wherein, TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the image surface S9 of the lens assembly 100, and the unit of TTL is mm. When the above relationship is satisfied, the lens assembly 100 has a shorter optical length, thereby facilitating the realization of a miniaturized design; when lens subassembly 100 is applied to medical equipment, be favorable to reducing medical equipment's size in order to conveniently put into the medical equipment narrow and small internal or the space in space, greatly avoid causing the sore to the human body because of medical equipment is bulky, simultaneously, also more be favorable to medical equipment's nimble removal to gather omnidirectional image information.

FNO 3.0; wherein, FNO is the lens subassembly 100 f-number. When the above relationship is satisfied, the lens assembly 100 has excellent image pickup performance, which is advantageous for satisfying the characteristic of high relative illuminance.

SD1 ═ 1.556; wherein SD1 is the maximum effective half aperture of the object-side surface S1 of the first lens L1, and SD1 is in mm. Satisfying the above relationship is advantageous for the miniaturization design of the lens assembly 100.

f/f1 ═ 0.524; where f is the total effective focal length of the lens assembly 100, and f1 is the effective focal length of the first lens L1. When the above relationship is satisfied, it is favorable for the light with a large viewing angle to enter the lens assembly 100, thereby satisfying the design requirement of miniaturization.

TTL/BF 3.317; wherein, TTL is an axial distance from the object-side surface S1 of the first lens L1 to the image plane S9 of the lens assembly 100, and BF is an axial distance from the image-side surface S6 of the third lens L3 to the image plane S9 of the lens assembly 100.

TTL/ImgH is 2.667; wherein, TTL is the distance on the optical axis from the object side surface S1 of the first lens L1 to the image plane S9 of the lens assembly 100, and ImgH is half the diagonal length of the effective pixel area of the lens assembly 100 on the image plane S9. When the above relationship is satisfied, the total optical length of the lens assembly 100 can be effectively compressed, thereby satisfying the requirement of miniaturization design.

CT1/ET 1-1.118; CT1 is the central thickness of the first lens element L1, and ET1 is the thickness of the first lens element L1 at the maximum effective aperture of the object-side surface S1. When the above relationship is satisfied, the thickness ratio of the center thickness to the edge thickness (the thickness at the maximum effective aperture of the object-side surface S1) of the first lens element L1 can be made uniform, which is favorable for processing and molding the first lens element L1.

Tan [ FOV (1.0F)/2]/F1 ═ 1.189; where FOV (1.0F) is the maximum angle of view of the lens assembly 100, F1 is the effective focal length of the first lens L1, and F1 is in mm. When the above relationship is satisfied, the effective focal length of the first lens L1 can be configured properly, so that the lens assembly 100 has a large angle of view.

In the first embodiment, the total effective focal length F of the lens assembly 100 is 1.063mm, the F-number FNO is 3.0, the maximum field angle FOV is 135.0 degrees (deg.), that is, FOV (1.0F) is 135.0 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image surface S9 on the optical axis is 4.0 mm.

In addition, the parameters of the lens assembly 100 are given by table 1 and table 2. The elements from the object side to the image side are arranged in the order of the elements from top to bottom in table 1. In the same lens, the surface with the smaller surface number is the object side surface of the lens, and the surface with the larger surface number is the image side surface of the lens, and for example, the

surface numbers

1 and 2 correspond to the object side surface S1 and the image side surface S2 of the first lens L1, respectively. The Y radius in table 1 is the radius of curvature of the object-side surface or the image-side surface of the corresponding surface number at the optical axis. The first value in the "thickness" parameter column of the first lens element L1 is the thickness of the lens element along the optical axis (center thickness), and the second value is the distance from the image-side surface of the lens element to the object-side surface of the subsequent lens element along the optical axis. The numerical value of the stop STO in the "thickness" parameter column is the distance on the optical axis from the stop STO to the vertex of the object-side surface of the subsequent lens (the vertex refers to the intersection point of the lens and the optical axis), the direction from the object-side surface of the first lens to the image-side surface of the last lens is the positive direction of the optical axis by default, when the value is negative, the stop STO is shown to be arranged on the right side of the vertex of the object-side surface of the subsequent lens, and if the thickness of the stop STO is positive, the stop is arranged on the left side of the vertex of the object-side surface. The numerical value corresponding to the surface number 9 in the "thickness" parameter of the infrared filter 110 is the distance on the optical axis from the image side surface S8 to the image surface S9 of the infrared filter 110. Table 2 is a table of relevant parameters of the aspherical surface of each lens in table 1, where K is a conic constant and Ai is a coefficient corresponding to the i-th high-order term in the aspherical surface type formula.

In the following examples, the refractive index, abbe number, and focal length of each lens are numerical values at a reference wavelength.

TABLE 1

TABLE 2

Second embodiment

In the second embodiment shown in fig. 4, the lens assembly 100 includes, in order from the object side to the image side, the first lens element L1 with negative refractive power, the stop STO, the second lens element L2 with positive refractive power, the third lens element L3 with positive refractive power, and the ir filter 110. In addition, fig. 5 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the lens assembly 100 in the second embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength (see the notation in table 1). Fig. 6 is a graph of relative illuminance of the lens assembly 100 according to the second embodiment with the abscissa being a half-image height value and the ordinate being a relative illuminance value.

In addition, the parameters of the lens assembly 100 are given in tables 3 and 4, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

In the second embodiment, the total effective focal length f of the lens assembly 100 is 1.07mm, the f-number FNO is 2.8, the maximum field angle FOV is 150.0 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image surface S9 on the optical axis is 4.066 mm.

TABLE 3

TABLE 4

The following data can be derived according to the provided parameter information:

third embodiment

In the third embodiment shown in fig. 7, the lens assembly 100 includes, in order from the object side to the image side, the first lens element L1 with negative refractive power, the stop STO, the second lens element L2 with positive refractive power, the third lens element L3 with positive refractive power, and the ir filter 110. In addition, fig. 8 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the lens assembly 100 in the third embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength (see the notation in table 1). Fig. 9 is a graph of relative illuminance of the lens assembly 100 according to the third embodiment with a half-image height value on the abscissa and a relative illuminance value on the ordinate.

In addition, the parameters of the lens assembly 100 are given in tables 5 and 6, and the definitions of the parameters can be obtained from the first embodiment, which is not repeated herein.

In the third embodiment, the total effective focal length f of the lens assembly 100 is 1.057mm, the f-number FNO is 2.4, the maximum field angle FOV is 161.0 degrees (deg.), and the distance TTL between the object-side surface S1 of the first lens L1 and the image surface S9 on the optical axis is 4.225 mm.

TABLE 5

TABLE 6

fourth embodiment

In the fourth embodiment shown in fig. 10, the lens assembly 100 includes, in order from the object side to the image side, the first lens element L1 with negative refractive power, the stop STO, the second lens element L2 with positive refractive power, the third lens element L3 with positive refractive power, and the ir filter 110. In addition, fig. 11 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the lens assembly 100 in the fourth embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength (see the notation in table 1). Fig. 12 is a graph of relative illuminance of the lens assembly 100 according to the fourth embodiment with the abscissa being a half-image height value and the ordinate being a relative illuminance value.

In addition, the parameters of the lens assembly 100 are given in tables 7 and 8, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

In the fourth embodiment, the total effective focal length f of the lens assembly 100 is 1.027mm, the f-number FNO is 3.0, the maximum field angle FOV is 142.4 degrees (deg.), and the distance TTL from the object side surface S1 of the first lens L1 to the image surface S9 on the optical axis is 3.8 mm.

TABLE 7

TABLE 8

fifth embodiment

In the fifth embodiment shown in fig. 13, the lens assembly 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a stop STO, a second lens element L2 with positive refractive power, a third lens element L3 with positive refractive power, and an ir filter 110. In addition, fig. 14 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the lens assembly 100 in the fifth embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength (see the notation in table 1). Fig. 15 is a graph of relative illuminance of the lens assembly 100 according to the fifth embodiment with a half-image height value on the abscissa and a relative illuminance value on the ordinate.

In addition, the parameters of the lens assembly 100 are given in tables 9 and 10, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

In the fifth embodiment, the total effective focal length f of the lens assembly 100 is 1.051mm, the f-number FNO is 2.2, the maximum field angle FOV is 145.6 degrees (deg.), and the distance TTL from the object-side surface S1 of the first lens L1 to the image surface S9 on the optical axis is 4.123 mm.

TABLE 9

Watch 10

sixth embodiment

In the sixth embodiment shown in fig. 16, the lens assembly 100 includes, in order from an object side to an image side, a first lens element L1 with negative refractive power, a stop STO, a second lens element L2 with positive refractive power, a third lens element L3 with positive refractive power, and an ir filter 110. In addition, fig. 17 is a spherical aberration diagram (mm), an astigmatism diagram (mm), and a distortion diagram (%) of the lens assembly 100 in the sixth embodiment, wherein the astigmatism diagram and the distortion diagram are data diagrams at a reference wavelength (see the notation in table 1). Fig. 18 is a graph of relative illuminance of the lens assembly 100 according to the sixth embodiment with a half-image height value on the abscissa and a relative illuminance value on the ordinate.

In addition, the parameters of the lens assembly 100 are given in tables 11 and 12, and the definitions of the parameters can be obtained from the first embodiment, which is not described herein.

In the sixth embodiment, the total effective focal length f of the lens assembly 100 is 1.061mm, the f-number FNO is 3.0, the maximum field angle FOV is 139.6 degrees (deg.), and the distance TTL between the object-side surface S1 of the first lens L1 and the image surface S9 on the optical axis is 4.154 mm.

TABLE 11

TABLE 12

referring to fig. 19, in some embodiments, the lens assembly and the photosensitive element 210 are assembled into the image capturing module 200, and the photosensitive element 210 is disposed on the image side of the lens assembly. The light beam carrying the subject information sequentially passes through the first lens L1, the stop STO, the second lens L2, the third lens L3 and the infrared filter 110, is imaged on the image plane S9, and is received by the photosensitive element 210. In some embodiments, the image plane S9 may be a receiving plane where the light receiving element 210 receives light. In addition, the photosensitive element 210 may be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). By adopting the lens assembly, the image capturing module 200 has miniaturization and wide-angle characteristics.

In some embodiments, the distance between the photosensitive element 210 and each lens in the lens assembly is relatively fixed, and at this time, the image capturing module 200 is a fixed focus module. In other embodiments, a voice coil motor may be provided to enable the photosensitive element 210 to move relative to each lens in the lens assembly, so as to achieve the focusing function. Specifically, the voice coil motor can drive the lens barrel carrying each lens of the lens assembly to move so as to realize the focusing function.

Further, the image capturing module 200 may be applied to a medical device or a robot requiring a micro-camera function. Specifically, referring to fig. 20, the image capturing module 200 in some embodiments is applied to an endoscope 30, and the endoscope 30 can be used as a medical examination device such as a gastroscope or an enteroscope. The endoscope 30 includes a probe in which the image capturing module 200 is installed and a display module 310. In addition, the detecting head may further include a light source to cooperate with the image capturing module 200 to capture an image in a dark environment. Specifically, the detecting head is placed inside the human body, the image capturing module 200 can obtain image information of the inside of the human body, and transmit and display the image information to the display module 310. By adopting the image capturing module 200, the volume of the probe of the endoscope 30 can be made smaller, so that the sore injury to the human body can be reduced in the human body by the probe; meanwhile, since the image capturing module 200 has a wide-angle characteristic, the probe can acquire a large-range image during probing, so as to acquire more complete probing information, which is beneficial to precise detection. In other embodiments, the image capturing module 200 can also be applied to an industrial inspection apparatus for inspecting the microstructure of a workpiece.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A lens assembly, comprising, in order from an object side to an image side:

a diaphragm;

the lens assembly satisfies the following relationship:

FOV(1.0F)≥130°；

wherein the FOV (1.0F) is the maximum field angle of the lens assembly.

2. The lens assembly of claim 1, wherein the following relationship is satisfied:

FOV(0.7F)≥100°；

wherein, the FOV (0.7F) is the field angle corresponding to the lens assembly at the image height of 0.7 field of view.

3. The lens assembly of claim 1, wherein the following relationship is satisfied:

RI (1.0F) > 50%; wherein RI (1.0F) is the relative illumination of the lens assembly in the 1.0 field of view;

alternatively, the relative illumination of all fields of view of the lens assembly is greater than 50%.

4. The lens assembly of claim 1, wherein the following relationship is satisfied:

TTL＜4.25；

wherein, TTL is the distance on the optical axis from the object side surface of the first lens to the image surface of the lens component, and the unit of TTL is mm.

5. The lens assembly of claim 1, wherein the following relationship is satisfied:

FNO≤3.0；

wherein FNO is the f-number of the lens assembly.

6. The lens assembly of claim 1, wherein the following relationship is satisfied:

SD1≤1.7；

wherein SD1 is the maximum effective half aperture of the object side surface of the first lens, and SD1 is in mm.

7. The lens assembly of claim 1, wherein the following relationship is satisfied:

-1＜f/f1＜0；

wherein f is the total effective focal length of the lens assembly, and f1 is the effective focal length of the first lens.

8. The lens assembly of claim 1, wherein the following relationship is satisfied:

3＜TTL/BF＜5；

wherein, TTL is a distance on an optical axis from an object side surface of the first lens to an image surface of the lens assembly, and BF is a distance on the optical axis from an image side surface of the third lens to the image surface of the lens assembly.

9. The lens assembly of claim 1, wherein the following relationship is satisfied:

TTL/ImgH＜2.8；

wherein, TTL is a distance on an optical axis from an object side surface of the first lens to an image plane of the lens assembly, and ImgH is a half of a diagonal length of an effective pixel area of the lens assembly on the image plane.

10. The lens assembly of claim 1, wherein the following relationship is satisfied:

CT1/ET1＜1.5；

wherein CT1 is the central thickness of the first lens, and ET1 is the thickness of the first lens at the maximum effective aperture of the object side.

11. The lens assembly of claim 1, wherein the following relationship is satisfied:

-20＜Tan[FOV(1.0F)/2]/f1＜-1；

wherein f1 is the effective focal length of the first lens, and the unit of f1 is mm.

12. An image capturing module, comprising a photosensitive element and the lens assembly of any one of claims 1 to 11, wherein the photosensitive element is disposed on an image side of the lens assembly.

13. A medical device comprising the image capture module of claim 12.