Optical imaging lens combination and optical endoscope device thereof

Abstract

The invention discloses an optical imaging lens assembly applied to an optical endoscope device and the optical endoscope device. The optical imaging lens assembly comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially aligned from an object side to an image side. The first lens has a negative refractive index, and further has a first object side surface and a first image side concave surface. The second lens has a positive refractive index, and further has a second object-side concave surface and a second image-side convex surface. The third lens has a positive refractive index, and further has a third object-side convex surface and a third image-side convex surface. The fourth lens has a negative refractive index, and further has a fourth object-side concave surface and a fourth image-side surface. The concave feature of the first image-side concave surface faces the image side, and the concave feature of the second object-side concave surface faces the object side.

Description

TECHNICAL FIELD

[0001] The present application provides an optical imaging lens assembly and an optical endoscope device thereof, in particular, an optical imaging lens assembly and an optical endoscope device thereof capable of achieving small size and being applied in air and liquid. BACKGROUND

[0002] With the progress of technology, minimally invasive surgery has the advantages of small wound and fast recovery time, and is widely used in various types of medical procedures. The existing minimally invasive surgery can use an endoscope to observe the affected area, and the monitoring image is transmitted to the screen for visual judgment. The endoscope enters the biological body and may be immersed in the body fluid of the biological body; however, the lens assembly used by the traditional endoscope is not suitable for observing the affected area immersed in liquid, so the traditional endoscope is difficult to achieve the technical characteristics of small size and visual demand applied in air and liquid. SUMMARY

[0003] The present application provides an optical imaging lens assembly and an optical endoscope device thereof capable of achieving small size and being applied in air and liquid to solve the above problems.

[0004] The present application discloses an optical imaging lens assembly, which is aligned in order from the object side to the image side and includes a first lens, a second lens, a third lens, and a fourth lens. The first lens has a negative refractive power and further has a first object side surface and a first image side surface, wherein the first object side surface is a concave surface or a convex surface. The second lens has a positive refractive power and further has a second object side concave surface and a second image side convex surface. The third lens has a positive refractive power and further has a third object side convex surface and a third image side convex surface. The fourth lens has a negative refractive power and further has a fourth object side concave surface and a fourth image side surface. The concave feature of the first image side surface faces the image side, the concave feature of the second object side surface faces the object side, and the ratio of the curvature radius of the first image side surface to the curvature radius of the second object side surface is less than zero. The convex structure of the third image side surface faces the image side, the concave feature of the fourth object side surface faces the object side, and the ratio of the curvature radius of the third image side surface to the curvature radius of the fourth object side surface is greater than zero.

[0005] The application further discloses that the distortion aberration of the optical imaging lens combination in liquid water is between -20% and +2%. The sum of the refractive indexes of the first lens, the second lens, the third lens and the fourth lens is between 5.6 and 7.6. The field angle of the optical imaging lens combination is between 100 and 160 degrees, and the tangent value of the half field angle of the optical imaging lens combination is between 1.19 and 5.67. The field angle of the optical imaging lens combination in liquid water is between 60 and 100 degrees, and the tangent value of the half field angle of the optical imaging lens combination in the liquid water is between 0.58 and 1.19.

[0006] The application further discloses that the ratio of the first focal length of the first lens to the second focal length of the second lens is between -0.9 and +0.9. The ratio of the effective focal length of the optical imaging lens combination to the second focal length of the second lens is between -0.3 and +0.3. The ratio of the effective focal length of the optical imaging lens combination to the third focal length of the third lens is between 0.5 and 1.5. The ratio of the third focal length of the third lens to the fourth focal length of the fourth lens is less than zero. The radius of any one of the first lens, the second lens, the third lens and the fourth lens is less than or equal to 5 mm.

[0007] The application further discloses an optical endoscope device, which comprises an optical imaging lens combination, a light source and an optical sensor. The optical imaging lens combination is sequentially aligned from an object side to an image side and comprises a first lens, a second lens, a third lens and a fourth lens. The first lens has a negative refractive power and further has a first object side surface and a first image side concave surface, wherein the first object side surface is a concave surface or a convex surface. The second lens has a positive refractive power and further has a second object side concave surface and a second image side convex surface. The third lens has a positive refractive power and further has a third object side convex surface and a third image side convex surface. The fourth lens has a negative refractive power and further has a fourth object side concave surface and a fourth image side surface. The light source is used for projecting imaging light to the optical imaging lens combination. The optical sensor is used for receiving a monitoring image generated by the optical imaging lens combination. The concave feature of the first image side concave surface faces the image side, the concave feature of the second object side concave surface faces the object side, and the ratio of the curvature radius of the first image side concave surface to the curvature radius of the second object side concave surface is less than zero. The convex structure of the third image side convex surface faces the image side, the concave feature of the fourth object side concave surface faces the object side, and the ratio of the curvature radius of the third image side convex surface to the curvature radius of the fourth object side concave surface is greater than zero.

[0008] The first lens of the optical imaging lens combination of the present application can have a negative refractive power, which is used to refract large-angle incident light to achieve a wide viewing angle; the second lens can have a positive refractive power, which can focus the light rays refracted via the first lens to converge, which, in combination with the first lens, can reduce distortion and improve relative luminance; the third lens can have a positive refractive power, which further focuses the light rays refracted via the second lens, which, in combination with the second lens, can reduce aberration and improve image resolution; the fourth lens can have a negative refractive power, which is used to control the light rays refracted via the third lens to meet the chief ray angle of each field angle incident to the optical sensor, thereby effectively reducing chromatic aberration. The present application uses small-size lenses to make an optical imaging lens combination of an optical endoscope device, which constitutes a small-size wide-angle lens that can be applied in air and liquid water and can effectively correct aberration and spherical aberration, so that the optical imaging lens combination and the optical endoscope device thereof have good optical performance. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 A functional block diagram of an optical endoscope device of an embodiment of the present application.

[0010] Figure 2 A schematic diagram of an optical imaging lens combination of a first embodiment of the present application.

[0011] Figure 3 A distortion aberration schematic diagram of the optical imaging lens combination of the first embodiment of the present application in air.

[0012] Figure 4 A distortion aberration schematic diagram of the optical imaging lens combination of the first embodiment of the present application in liquid water.

[0013] Figure 5 A data schematic diagram of various structures and optical parameters of the optical imaging lens combination of the first embodiment of the present application.

[0014] Figure 6 A data schematic diagram of optical data of the optical imaging lens combination of the first embodiment of the present application.

[0015] Figure 7 A data schematic diagram of aspheric surface data of the optical imaging lens combination of the first embodiment of the present application.

[0016] Figure 8 A schematic diagram of an optical imaging lens combination of a second embodiment of the present application.

[0017] Figure 9 A distortion aberration schematic diagram of the optical imaging lens combination of the second embodiment of the present application in air.

[0018] Figure 10The luminance change diagram of the optical imaging lens combination of the second embodiment of the present application in liquid water.

[0019] Figure 11 The data diagram of the structure and optical parameters of the optical imaging lens combination of the second embodiment of the present application.

[0020] Figure 12 The data diagram of the optical data of the optical imaging lens combination of the second embodiment of the present application.

[0021] Figure 13 The data diagram of the aspheric surface data of the optical imaging lens combination of the second embodiment of the present application.

[0022] Figure 14 The diagram of the optical imaging lens combination of the third embodiment of the present application.

[0023] Figure 15 The distortion aberration diagram of the optical imaging lens combination of the third embodiment of the present application in air.

[0024] Figure 16 The luminance change diagram of the optical imaging lens combination of the third embodiment of the present application in liquid water.

[0025] Figure 17 The data diagram of the structure and optical parameters of the optical imaging lens combination of the third embodiment of the present application.

[0026] Figure 18 The data diagram of the optical data of the optical imaging lens combination of the third embodiment of the present application.

[0027] Figure 19 The data diagram of the aspheric surface data of the optical imaging lens combination of the third embodiment of the present application.

[0028] In the diagram:

[0029] 10: optical endoscope device

[0030] 12: optical imaging lens combination

[0031] 14: light source

[0032] 16: optical sensor

[0033] 18: operation processor

[0034] 20: first lens

[0035] 201: first object side surface

[0036] 202: first image side surface (first image side concave surface)

[0037] 22: second lens

[0038] 221: second object-side surface (second object-side concave surface)

[0039] 222: second image-side surface (second image-side convex surface)

[0040] 24: aperture

[0041] 26: third lens

[0042] 261: third object-side surface (third object-side convex surface)

[0043] 262: third image-side surface (third image-side convex surface)

[0044] 28: fourth lens

[0045] 281: fourth object-side surface (fourth object-side concave surface)

[0046] 282: fourth image-side surface (fourth image-side convex or concave surface)

[0047] 30: imaging surface

[0048] Fno: f-number

[0049] H-IMH: maximum imaging height

[0050] f: effective focal length

[0051] f1: first focal length

[0052] f2: second focal length

[0053] f3: third focal length

[0054] f4: fourth focal length

[0055] H-FOV: half field of view in air

[0056] WH-FOV: half field of view in liquid water

[0057] R2: radius of curvature of first image-side concave surface

[0058] R3: radius of curvature of second object-side concave surface

[0059] R6: radius of curvature of third image-side convex surface

[0060] R7: radius of curvature of fourth object-side concave surface

[0061] n1: first refractive index

[0062] n2: second refractive index

[0063] n3: third refractive index

[0064] n4: fourth refractive

[0065] K, A2, A4, A6, A8, A10, A12, A14, A16: aspherical coefficients

[0066] V1: first Abbe number

[0067] V2: second Abbe number

[0068] V3: third Abbe number

[0069] V4: fourth Abbe number

[0070] A1: object side

[0071] A2: image side

[0072] I: optical axis. DETAILED DESCRIPTION

[0073] As used in the specification and claims of this application, the terms "concave" and "convex" are to be interpreted based on the definitions set forth in this specification. An optical system of this specification includes at least one lens that receives an imaging ray parallel to the optical axis within an angle of half field of view (HFOV) from the optical axis. The imaging ray is imaged by the optical system on an image plane. By "a lens has positive (or negative) refractive power," it is meant that the paraxial refractive power of the lens, calculated according to Gaussian optics, is positive (or negative). By "the object side (or image side) of a lens" is defined as a certain range of the lens surface through which the imaging ray passes. When the imaging ray parallel to the optical axis passes through a region, if the imaging ray is deflected toward the optical axis and the intersection point of the imaging ray and the optical axis is on the image side of the lens, then the region is convex. When the imaging ray parallel to the optical axis passes through a region, if the extension line of the imaging ray intersects the optical axis on the object side of the lens, then the region is concave.

[0074] On the other hand, the determination of the concave / convex surface shape of the image side or object side of a lens can also be made by the way commonly known to those skilled in the art, i.e., by the sign of the radius of curvature (abbreviated as R value) of the paraxial ray. The R value is commonly used in optical design software, such as Zemax or CodeV. The R value is also commonly found in the lens data sheet of the optical design software. In the case of the object side, when the R value is positive, it is determined that the object side is convex; when the R value is negative, it is determined that the object side is concave. Conversely, in the case of the image side, when the R value is positive, it is determined that the image side is concave; when the R value is negative, it is determined that the image side is convex. The results of this method of determination are consistent with the results of the aforementioned determination method by the intersection point of the ray / extension line of the ray and the optical axis, i.e., the determination of the concave / convex surface shape by the focus point of the ray parallel to the optical axis being on the object side or the image side of the lens.

[0075] Referring to Figure 1 , Figure 1 is a functional block diagram of an optical endoscope device 10 according to an embodiment of the present application. The optical endoscope device 10 can include an optical imaging lens assembly 12, a light source 14, an optical sensor 16, and a computing processor 18. The optical endoscope device 10 can be a medical device; or a part of a medical device. The optical endoscope device 10 usually has a soft tube shape or a similar design, and can be inserted into a living body to take monitoring images for further analysis and judgment. The light source 14 provides imaging light. The imaging light is projected into a diseased part of the living body through the optical imaging lens assembly 12, and the monitoring images generated by the optical imaging lens assembly 12 are received by the optical sensor 16. The computing processor 18 can store and analyze the monitoring images, or transmit the monitoring images to an external device for analysis. The computing processor 18 is an optional component, and can be a processing unit independent of the optical sensor 16, or a processing module built in the optical sensor 16, or an external component, which varies according to design requirements.

[0076] Referring to Figure 2 , Figure 2 is a schematic diagram of the optical imaging lens assembly 12 according to the first embodiment of the present application. The optical imaging lens assembly 12 is disposed between an object side Al where an object (not shown) is placed and an image side A2 where an image is formed, and sequentially includes a first lens 20, a second lens 22, an aperture 24, a third lens 26, a fourth lens 28, and an imaging surface 30 in alignment with each other along an optical axis I. Generally, the first lens 20, the second lens 22, the third lens 26, and the fourth lens 28 can be made of transparent glass, but the present application is not limited thereto. In the optical imaging lens assembly 12 of the present application, the first lens 20 and the fourth lens 28 have refractive powers, and the second lens 22 and the third lens 26 have positive refractive powers. The optical axis I is the optical axis of the entire optical imaging lens assembly 12, so the optical axis of each lens is the same as the optical axis of the optical imaging lens assembly 12.

[0077] The aperture 24 is disposed between the second lens 22 and the third lens 26. When a light ray (not shown) emitted from an object (not shown) located at the object side Al enters the optical imaging lens combination 12 of the present application, it will sequentially pass through the first lens 20, the second lens 22, the aperture 24, the third lens 26 and the fourth lens 28, and then focus on the imaging plane 30 at the image side A2 to form a clear image. In a possible embodiment of the present application, the optical imaging lens combination 12 can also optionally be provided with a filter (not shown) in front of the imaging plane 30, which can be a filter having various desired functions, such as a visible light cut-off filter, which is used to avoid the transmission of visible light in the ambient light source to the imaging plane 30 to affect the imaging quality.

[0078] Each lens in the optical imaging lens combination 12 of the present application has a respective object side surface facing the object side Al for passing the imaging light rays, and an image side surface facing the image side A2 for passing the imaging light rays. For example, the first lens 20 can have a first object side surface 201 and a first image side surface 202; the second lens 22 can have a second object side surface 221 and a second image side surface 222; the third lens 26 can have a third object side surface 261 and a third image side surface 262; and the fourth lens 28 can have a fourth object side surface 281 and a fourth image side surface 282. The structural characteristics of each object side surface and each image side surface will be described below respectively.

[0079] The first lens 20 can have a negative refractive power. The first object side surface 201 of the first lens 20 can be convex or concave, and the first image side surface 202 of the first lens 20 can be concave (i.e. first image side concave surface 202). Both the first object side surface 201 and the first image side surface 202 of the first lens 20 are spherical, but are not limited thereto. The negative refractive power lens design of the first lens 20 can refract large-angle incident light to achieve a wide viewing angle. The second lens 22 can have a positive refractive power. The second object side surface 221 of the second lens 22 can be concave (i.e. second object side concave surface 221), and the second image side surface 222 of the second lens 22 can be convex (i.e. second image side convex surface 222). Both the second object side concave surface 221 and the second image side convex surface 222 of the second lens 22 are spherical, but are not limited thereto. The positive refractive power lens design of the second lens 22 focuses the light rays refracted by the first lens 20 for convergence, which in combination can reduce distortion and improve relative illumination.

[0080] The third lens 26 can have a positive refractive power, the third object side surface 261 of the third lens 26 can be a convex surface (i.e., third object side convex surface 261), and the third image side surface 262 of the third lens 26 can be a convex surface (i.e., third image side convex surface 262). Both the third object side convex surface 261 and the third image side convex surface 262 of the third lens 26 can be spherical surfaces, but are not limited thereto. The positive refractive power lens design of the third lens 26 can further focus the light rays refracted by the second lens 22, both of which are combined to reduce aberration and improve image resolution. The fourth lens 28 can have a negative refractive power, the fourth object side surface 281 of the fourth lens 28 can be a concave surface (i.e., fourth object side concave surface 281), and the fourth image side surface 282 of the fourth lens 28 can be a convex surface or a concave surface (i.e., fourth image side convex surface or concave surface 282). Both the fourth object side concave surface 281 and the fourth image side convex surface 282 of the fourth lens 28 can be spherical surfaces, but are not limited thereto. The negative refractive power lens design of the fourth lens 28 can control the light rays refracted by the third lens 26 to meet the chief ray angle of each field angle incident to the optical sensor 16, both of which are combined to effectively reduce chromatic aberration.

[0081] It is particularly noted that the concave feature of the first image side concave surface 202 of the first lens 20 faces the image side A2, the concave feature of the second object side concave surface 221 of the second lens 22 faces the object side Al, and the ratio of the curvature radius R2 of the first image side concave surface 202 to the curvature radius R3 of the second object side concave surface 221 is preferably less than zero. In addition, the convex feature of the third image side convex surface 262 of the third lens 26 faces the image side A2, the concave feature of the fourth object side concave surface 281 of the fourth lens 28 faces the object side Al, and the ratio of the curvature radius R6 of the third image side convex surface 262 to the curvature radius R7 of the fourth object side concave surface 281 is preferably greater than zero.

[0082] The present application defines the EFL as the effective focal length f of the optical imaging lens combination 12, and defines the H-FOV as the half angle of view or half field angle of the optical imaging lens combination 12 in air, i.e., half of the maximum field of view (FOV); and defines the WH-FOV as the half angle of view or half field angle of the optical imaging lens combination 12 in liquid water. In addition, the present application can further define: f as the effective focal length of the optical imaging lens combination 12; f1 as the first focal length of the first lens 20; f2 as the second focal length of the second lens 22; f3 as the third focal length of the third lens 26; f4 as the fourth focal length of the fourth lens 28; n1 as the first refractive index of the first lens 20; n2 as the second refractive index of the second lens 22; n3 as the third refractive index of the third lens 26; n4 as the fourth refractive index of the fourth lens 28; V1 as the first Abbe number of the first lens 20; V2 as the second Abbe number of the second lens 22; V3 as the third Abbe number of the third lens 26; and V4 as the fourth Abbe number of the fourth lens 28.

[0083] Therefore, the distortion aberration of the optical imaging lens combination 12 in liquid water can be designed to be between -20% and +2%. The sum of the refractive indexes of the first lens 20, the second lens 22, the third lens 26 and the fourth lens 28 can be designed to be between 5.6 and 7.6. The field of view angle of the optical imaging lens combination 12 in air can be between 100 and 160 degrees, and the tangent value of the half field of view angle H-FOV of the optical imaging lens combination 12 in air can be between 1.19 and 5.67; accordingly, the field of view angle of the optical imaging lens combination 12 in liquid water can be between 60 and 100 degrees, and the tangent value of the half field of view angle WH-FOV of the optical imaging lens combination 12 in liquid water can be between 0.58 and 1.19. On the other hand, the ratio of the first focal length fl of the first lens 20 to the second focal length f2 of the second lens 22 can be between -0.9 and +0.9; the ratio of the effective focal length f of the optical imaging lens combination 12 to the second focal length f2 of the second lens 22 can be between -0.3 and +0.3; the ratio of the effective focal length f of the optical imaging lens combination 12 to the third focal length f3 of the third lens 26 can be between 0.5 and 1.5; and the ratio of the third focal length f3 of the third lens 26 to the fourth focal length f4 of the fourth lens 28 can be less than zero. The radius of any one of the first lens 20, the second lens 22, the third lens 26 and the fourth lens 28 can be less than or equal to 5 mm.

[0084] Please refer to Figure 3 to FIG. 7, Figure 3 the distortion aberration diagram of the optical imaging lens combination 12 of the first embodiment of the present application in air, Figure 4 the distortion aberration diagram of the optical imaging lens combination 12 of the first embodiment of the present application in liquid water, Figure 5 the data diagram of the structural and optical parameters of the optical imaging lens combination 12 of the first embodiment of the present application, Figure 6 the data diagram of the optical data of the optical imaging lens combination 12 of the first embodiment of the present application, Figure 7 the data diagram of the aspheric surface data of the optical imaging lens combination 12 of the first embodiment of the present application. The distortion aberration of the imaging surface 30 of the optical imaging lens combination 12 in air and in liquid water is shown in Figures 3 to 5 The Y axis of the distortion aberration diagram represents the image height, and the highest point is 1.0.

[0085] As shown in Figure 6The thickness of the first lens 20 can be 0.30 mm, the thickness of the second lens 22 can be 0.26 mm, the thickness of the third lens 26 can be 0.46 mm, the thickness of the fourth lens 28 can be 0.35 mm, the thickness of the aperture 24 can be 0.11 mm, the thickness of the filter can be 0.45 mm, the air gap between the first lens 20 and the second lens 22 can be 0.44 mm, the air gap between the second lens 22 and the aperture 24 can be 0.25 mm, the air gap between the third lens 32 and the fourth lens 28 can be 0.06 mm, the air gap between the fourth lens 28 and the filter can be 0.76 mm, and the air gap between the filter and the imaging surface 30 can be 0.01 mm. The aspherical coefficients K, A2, A4, A6, A8, A10, A12, A14, and A16 of the optical imaging lens combination 12 of the first embodiment are shown as follows. Figure 7

[0086] Please refer to Figures 8 to 13 , Figure 8 the schematic diagram of the optical imaging lens combination 12 of the second embodiment of the present application, Figure 9 the schematic diagram of the distortion aberration of the optical imaging lens combination 12 of the second embodiment of the present application in air, Figure 10 the schematic diagram of the brightness variation of the optical imaging lens combination 12 of the second embodiment of the present application in liquid water, Figure 11 the schematic diagram of the data of the structures and optical parameters of the optical imaging lens combination 12 of the second embodiment of the present application, Figure 12 the schematic diagram of the data of the optical data of the optical imaging lens combination 12 of the second embodiment of the present application, Figure 13 the schematic diagram of the data of the aspherical data of the optical imaging lens combination 12 of the second embodiment of the present application. In the second embodiment, the features and functions with the same numerals as those of the first embodiment are similar, and will not be repeated here. The structures and optical parameters, optical data, and aspherical data of the optical imaging lens combination 12 of the second embodiment are slightly different from those of the first embodiment, as shown in the following table. Figures 11 to 13

[0087] Therefore, the distortion aberration of the imaging surface 30 of the optical imaging lens combination 12 in air and in liquid water can refer to the data shown in Figures 9 to 11 The Y-axis of the distortion aberration graph and the brightness variation graph represents the image height, and the highest point is 1.0. As Figure 12 ​​As shown, the thickness of the first lens 20 can be 0.28 mm, the thickness of the second lens 22 can be 0.61 mm, the thickness of the third lens 26 can be 0.52 mm, the thickness of the fourth lens 28 can be 0.29 mm, the thickness of the aperture 24 can be -0.08 mm, the thickness of the filter can be 0.45 mm, the air gap between the first lens 20 and the second lens 22 can be 0.58 mm, the air gap between the second lens 22 and the aperture 24 can be 0.35 mm, the air gap between the third lens 32 and the fourth lens 28 can be 0.02 mm, the air gap between the fourth lens 28 and the filter can be 1.42 mm, and the air gap between the filter and the imaging surface 30 can be 0.01 mm. The aspheric coefficients K, A2, A4, A6, A8, A10, A12, A14, and A16 of the optical imaging lens combination 12 of the second embodiment are shown as follows. Figure 13

[0088] Please refer to Figures 14 to 19 , Figure 14 the schematic diagram of the optical imaging lens combination 12 of the third embodiment of the present application, Figure 15 the schematic diagram of the distortion aberration of the optical imaging lens combination 12 of the third embodiment of the present application in air, Figure 16 the schematic diagram of the brightness variation of the optical imaging lens combination 12 of the third embodiment of the present application in liquid water, Figure 17 the schematic diagram of the data of the structures and optical parameters of the optical imaging lens combination 12 of the third embodiment of the present application, Figure 18 the schematic diagram of the data of the optical data of the optical imaging lens combination 12 of the third embodiment of the present application, Figure 19 the schematic diagram of the data of the aspheric data of the optical imaging lens combination 12 of the third embodiment of the present application. In the third embodiment, the features and functions with the same numerals as those of the previous embodiments are similar, and will not be repeated here. The structures and optical parameters, optical data, and aspheric data of the optical imaging lens combination 12 of the third embodiment are slightly different from those of the previous embodiments, as shown in the following table. Figures 17 to 19

[0089] Accordingly, the distortion aberration of the imaging surface 300 of the optical imaging lens combination 12 in air and in liquid water can refer to the data shown in Figure 15 and Figure 16 The Y-axis of the distortion aberration graph and the brightness variation graph represents the image height, and the highest point is 1.0. As Figure 18 ​​As shown, the thickness of the first lens 20 can be 0.37 mm, the thickness of the second lens 22 can be 0.76 mm, the thickness of the third lens 26 can be 0.68 mm, the thickness of the fourth lens 28 can be 0.30 mm, the thickness of the aperture 24 can be 0.01 mm, the thickness of the filter can be 0.45 mm, the air gap between the first lens 20 and the second lens 22 can be 0.56 mm, the air gap between the second lens 22 and the aperture 24 can be 0.15 mm, the air gap between the third lens 32 and the fourth lens 28 can be 0.01 mm, the air gap between the fourth lens 28 and the filter can be 0.90 mm, and the air gap between the filter and the imaging surface 30 can be 0.01 mm. The aspheric coefficients K, A2, A4, A6, A8, A10, A12, A14, and A16 of the optical imaging lens combination 12 of the third embodiment are shown as follows. Figure 19

[0090] To ensure the optical quality of the optical imaging lens combination and taking into consideration the ease of manufacture, the present application can selectively make appropriate combinations and designs of the radius of curvature, the thickness of the lens, the air gap, the refractive index, and the Abbe number of different embodiments. The content disclosed in each embodiment of the present application includes, but is not limited to, the optical parameters such as the focal length, the thickness of the lens, and the Abbe number. As long as the numerical limits described in the three embodiments above are satisfied, the optical imaging lens combination of the present application can have a better configuration. The range covered by the above-mentioned optical parameters, the comparison relationship between the optical parameters, and the maximum value, the minimum value, and the numerical range within the maximum value and the minimum value of the conditional expressions are all features that can be implemented by the present application, and all belong to the scope disclosed by the present application. The above is only an example and should not be limited. The embodiments of the present application can be implemented, and part of the feature combinations including, but not limited to, the combination of the surface shape, the refractive power, and the conditional expression of the features can be extracted in the same embodiment. The disclosure of the embodiments of the present application is a specific embodiment to illustrate the principle of the present application, and should not limit the present application to the disclosed embodiments. In other words, the embodiments of the present application and the accompanying drawings are only for demonstration and are not limited thereto.

[0091] ​In summary, the first lens of the optical imaging lens combination of the present application can have a negative refractive power to refract large-angle incident light to achieve a wide viewing angle; the second lens can have a positive refractive power to focus the light rays refracted by the first lens to converge, which, in combination with the first lens, can reduce distortion and improve relative luminance; the third lens can have a positive refractive power to further focus the light rays refracted by the second lens, which, in combination with the second lens, can reduce aberration and improve image resolution; and the fourth lens can have a negative refractive power to control the light rays refracted by the third lens to conform to the chief ray angle of each field angle incident to the optical sensor to effectively reduce chromatic aberration. The present application uses small-size lenses to produce an optical imaging lens combination of an optical endoscope device, which constitutes a small-size wide-angle lens that can be applied in air and liquid water and can effectively correct aberration and spherical aberration, so that the optical imaging lens combination and the optical endoscope device thereof have good optical performance.

[0092] The above description is only the preferred embodiment of the present application, and any equivalent change and modification made within the scope of the present application should be included in the scope of the present application.

Claims

1. An optical imaging lens combination, aligned in order from an object side to an image side and comprising a first lens, a second lens, a third lens, and a fourth lens, characterized in that, The optical imaging lens combination comprises: The first lens has a negative refractive power and further has a first object-side surface and a first image-side concave surface, the first object-side surface being a concave surface or a convex surface; The second lens has a positive refractive power and further has a second object-side concave surface and a second image-side convex surface; The third lens has a positive refractive power and further has a third object-side convex surface and a third image-side convex surface; and The fourth lens has a negative refractive power and further has a fourth object-side concave surface and a fourth image-side surface; The first image-side concave surface has a concave feature facing the image side, the second object-side concave surface has a concave feature facing the object side, and the ratio of the curvature radius of the first image-side concave surface to the curvature radius of the second object-side concave surface is less than zero; The third image-side convex surface has a convex structure facing the image side, the fourth object-side concave surface has a concave feature facing the object side, and the ratio of the curvature radius of the third image-side convex surface to the curvature radius of the fourth object-side concave surface is greater than zero.

2. The optical imaging lens combination according to claim 1, wherein, The distortion aberration of the optical imaging lens combination in liquid water is between -20% and +2%.

3. The optical imaging lens combination according to claim 1, wherein, The total refractive index of the first lens, the second lens, the third lens and the fourth lens is between 5.6 and 7.

6.

4. The optical imaging lens combination according to claim 1, wherein, The field of view angle of the optical imaging lens combination is between 100 and 160 degrees, and the tangent value of the half field of view angle of the optical imaging lens combination is between 1.19 and 5.

67.

5. The optical imaging lens combination according to claim 1, wherein, The field of view angle of the optical imaging lens combination in liquid water is between 60 and 100 degrees, and the tangent value of the half field of view angle of the optical imaging lens combination in the liquid water is between 0.58 and 1.

19.

6. The optical imaging lens assembly according to claim 1, wherein, The ratio of the first focal length of the first lens to the second focal length of the second lens is between -0.9 and +0.

9.

7. The optical imaging lens combination according to claim 1, wherein, The ratio of the effective focal length of the optical imaging lens combination to the second focal length of the second lens is between -0.3 and +0.

3.

8. The optical imaging lens combination according to claim 1, wherein, The ratio of the effective focal length of the optical imaging lens combination to the third focal length of the third lens is between 0.5 and 1.

5.

9. The optical imaging lens combination according to claim 1, wherein, The ratio of the third focal length of the third lens to the fourth focal length of the fourth lens is less than zero.

10. The optical imaging lens combination according to claim 1, wherein, The radius of any one of the first lens, the second lens, the third lens and the fourth lens is less than or equal to five millimeters.

11. An optical endoscope device, characterized by comprising: The optical imaging lens combination comprises: An optical imaging lens combination sequentially aligned from an object side to an image side and comprising a first lens, a second lens, a third lens and a fourth lens, the optical imaging lens combination comprising: The first lens has a negative refractive power and further has a first object-side surface and a first image-side concave surface, the first object-side surface being a concave surface or a convex surface; The second lens has a positive refractive power and further has a second object-side concave surface and a second image-side convex surface; The third lens has a positive refractive power and further has a third object-side convex surface and a third image-side convex surface; and The fourth lens has a negative refractive power and further has a fourth object-side concave surface and a fourth image-side surface; A light source for projecting imaging light to the optical imaging lens combination; and An optical sensor for receiving a monitoring image generated by the optical imaging lens combination; wherein a concave feature of the first image-side concave surface faces the image side, a concave feature of the second object-side concave surface faces the object side, and a ratio of a radius of curvature of the first image-side concave surface to a radius of curvature of the second object-side concave surface is less than zero. wherein a convex structure of the third image-side convex surface faces the image side, a concave feature of the fourth object-side concave surface faces the object side, and a ratio of a radius of curvature of the third image-side convex surface to a radius of curvature of the fourth object-side concave surface is greater than zero.

12. The optical endoscope device of claim 11, wherein The optical imaging lens combination has a distortion aberration in liquid water between -20% and +2%.

13. The optical endoscope device of claim 11, wherein The first lens, the second lens, the third lens, and the fourth lens have a refractive index sum between 5.6 and 7.

6.

14. The optical endoscope device of claim 11, wherein The optical imaging lens combination has a field of view angle between 100 and 160 degrees, and a tangent value of a half field of view angle of the optical imaging lens combination is between 1.19 and 5.

67.

15. The optical endoscope device of claim 11, wherein The optical imaging lens combination has a field of view angle in liquid water between 60 and 100 degrees, and a tangent value of a half field of view angle of the optical imaging lens combination in the liquid water is between 0.58 and 1.

19.

16. The optical endoscope device of claim 11, wherein A ratio of a first focal length of the first lens to a second focal length of the second lens is between -0.9 and +0.

9.

17. The optical endoscope device of claim 11, wherein A ratio of an effective focal length of the optical imaging lens combination to the second focal length of the second lens is between -0.3 and +0.

3.

18. The optical endoscope device of claim 11, wherein A ratio of the effective focal length of the optical imaging lens combination to a third focal length of the third lens is between 0.5 and 1.

5.

19. The optical endoscope device of claim 11, wherein A ratio of the third focal length of the third lens to a fourth focal length of the fourth lens is less than zero.

20. The optical endoscope device of claim 11, wherein Any one of the first lens, the second lens, the third lens, and the fourth lens has a radius less than or equal to five millimeters.

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