A hybrid lens combining glass and liquid lenses for large depth of field with dual telecentric lenses.

Abstract

This invention relates to the field of optical system technology, specifically to a hybrid glass lens and liquid lens with large depth of field and dual telecentric lenses. It includes a glass lens group, a liquid lens, and a lens stop. The glass lens group comprises 12 groups of single lenses and 3 groups of cemented doublet lenses. The lens stop has an object plane and an image plane at its two ends. By integrating the advantages of high telecentricity and low distortion of dual telecentric lenses with the advantages of variable curvature and adjustable depth of field of liquid lenses, a hybrid glass lens and liquid lens with large depth of field and dual telecentric lenses is successfully achieved. The telecentricity is less than 0.01 degrees, the distortion is less than 0.5%, and the depth of field is more than 20 times that of traditional dual telecentric lenses.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of optical systems, in particular to a glass lens and liquid lens mixed large-landscape-depth double-telecentric lens. BACKGROUND

[0002] When an online detection system detects whether the size of a processed workpiece meets the standard, the performance of a lens is required to be extremely high. A telecentric optical lens is widely applied to the field of precision measurement due to its unique optical advantages such as high telecentricity and low distortion.

[0003] However, although the traditional double-telecentric lens has the advantages of high telecentricity and low distortion, the depth of field of the lens is limited, and the lens is difficult to adapt to complex and changeable detection environments, especially when the lens needs to accurately measure workpieces at different distances, the limitation of the traditional double-telecentric lens is particularly prominent. SUMMARY

[0004] The application aims to provide a glass lens and liquid lens mixed large-landscape-depth double-telecentric lens, and aims to solve the technical problem that although the traditional double-telecentric lens has the advantages of high telecentricity and low distortion, the depth of field of the lens is limited, and the lens is difficult to adapt to complex and changeable detection environments, especially when the lens needs to accurately measure workpieces at different distances, the limitation of the traditional double-telecentric lens is particularly prominent.

[0005] To achieve the above-mentioned purpose, the application adopts a glass lens and liquid lens mixed large-landscape-depth double-telecentric lens, which comprises a glass lens group, a liquid lens and a lens diaphragm, the glass lens group comprises 12 single lenses and 3 double-cemented lenses, 8 single lenses are arranged at one end of the corresponding double-cemented lens, and the other 4 single lenses are arranged at the other end of the corresponding double-cemented lens, one double-cemented lens is located on the left side of the liquid lens, two double-cemented lenses are located on the right side of the liquid lens, the liquid lens is arranged beside the lens diaphragm, and a lens object plane and a lens image plane are arranged at the two ends of the lens diaphragm respectively.

[0006] Among them, the front and rear surface curvature radii of 8 single lenses are all >0, and the front and rear surfaces are curved towards the liquid lens, the front and rear surface curvature radii of 2 single lenses are all <0, and the front and rear surfaces are curved towards the liquid lens, the rear surface curvature radius of 1 single lens is >0, and the rear surface is curved away from the liquid lens, and 1 single lens is one of double-convex and plano-convex structure, the front surface curvature radius is >0, and the rear surface curvature radius is <0.

[0007] Among them, the driving mode of the liquid lens is one of electro-wetting and piezoelectric driving, the response time is less than or equal to 10 ms, and the curvature adjustment accuracy reaches ±0.0001.

[0008] The aperture of the lens diaphragm is adjustable, and the adjustment range is F / #=8-12, and the imaging requirements under different illumination conditions can be adapted.

[0009] The optical parameters of the lens are that the telecentricity is less than 0.01°, the distortion is less than 0.5%, and the depth of field is greater than or equal to 10 mm.

[0010] The liquid lens dynamically adjusts the depth of field of the lens by adjusting the curvature radius of the film.

[0011] The glass lens, liquid lens mixed large depth of field double telecentric lens of the present application, comprising a glass lens group, a liquid lens and a lens diaphragm, the glass lens group comprises 12 single lenses and 3 double cemented lenses, and the curvature radius and thickness of the 12 single lenses and 3 double cemented lenses satisfy the preset optical path matching condition, wherein 8 single lenses are arranged at one end of the corresponding double cemented lens, and the other 4 single lenses are arranged at the other end of the corresponding double cemented lens, wherein one double cemented lens is located on the left side of the liquid lens, and two double cemented lenses are located on the right side of the liquid lens, the liquid lens is arranged beside the lens diaphragm, and the lens object plane and the lens image plane are arranged at both ends of the lens diaphragm, by integrating the advantages of high telecentricity and low distortion of the double telecentric lens and the adjustable advantage of the variable depth of field of the liquid lens, the glass lens, liquid lens mixed large depth of field double telecentric lens is successfully realized, the telecentricity of the lens is less than 0.01 degree, the distortion is less than 0.5%, and the depth of field is more than 20 times of that of the traditional double telecentric lens, so that the technical problem that the traditional double telecentric lens has limited depth of field and is difficult to adapt to complex detection environment, especially when accurate measurement of workpieces at different distances is required, the limitation of the traditional double telecentric lens is particularly prominent is effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0013] Figure 1 It is a structure schematic view of the glass lens, liquid lens mixed large depth of field double telecentric lens of the present application.

[0014] Figure 2 It is a structure schematic view of the lens in embodiment one of the glass lens, liquid lens mixed large depth of field double telecentric lens of the present application.

[0015] Figure 3 is a trend chart of lens distortion in embodiment one of the glass lens and liquid lens mixed large-DOF dual-telecentric lens of the present application.

[0016] Figure 4 is a structural schematic diagram of the lens in embodiment two of the glass lens and liquid lens mixed large-DOF dual-telecentric lens of the present application.

[0017] Figure 5 is a trend chart of lens distortion in embodiment two of the glass lens and liquid lens mixed large-DOF dual-telecentric lens of the present application.

[0018] Figure 6 is a structural schematic diagram of the lens in embodiment three of the glass lens and liquid lens mixed large-DOF dual-telecentric lens of the present application.

[0019] Figure 7 is a trend chart of lens distortion in embodiment three of the glass lens and liquid lens mixed large-DOF dual-telecentric lens of the present application.

[0020] 1-first single lens, 2-second single lens, 3-third single lens, 4-fourth single lens, 5-fifth single lens, 6-sixth single lens, 7-seventh single lens, 8-eighth single lens, 9-ninth single lens, 10-tenth single lens, 11-11th single lens, 12-12th single lens, 13-first double cemented lens, 14-second double cemented lens, 15-third double cemented lens, 16-liquid lens, 17-lens stop, 18-lens object plane, 19-lens image plane. DETAILED DESCRIPTION

[0021] Embodiments of the present application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar components are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0022] Referring to Figures 1-7 , the present application provides a glass lens and liquid lens mixed large-DOF dual-telecentric lens, comprising a glass lens group, a liquid lens and a lens stop, the glass lens group comprises 12 single lenses and 3 double cemented lenses, wherein 8 single lenses are arranged at one end of the corresponding double cemented lens, and the other 4 single lenses are arranged at the other end of the corresponding double cemented lens, wherein one double cemented lens is located on the left side of the liquid lens, two double cemented lenses are located on the right side of the liquid lens, the liquid lens is arranged beside the lens stop, and the lens object plane and the lens image plane are arranged at both ends of the lens stop, respectively.

[0023] In this embodiment, by integrating the advantages of high telecentricity and low distortion of a dual telecentric lens with the advantages of adjustable depth of field of a liquid lens with variable curvature, a hybrid dual telecentric lens with a large depth of field, combining glass lens and liquid lens, is successfully realized. The lens telecentricity is less than 0.01 degrees, the distortion is less than 0.5%, and the depth of field is more than 20 times that of a traditional dual telecentric lens. Furthermore, the curvature radii of the 12 single lenses and the 3 cemented doublet lenses all meet the preset optical path matching conditions with their thickness. This effectively solves the technical problem that although traditional dual telecentric lenses have the advantages of high telecentricity and low distortion, their limited depth of field makes them difficult to adapt to complex and changing detection environments, especially when precise measurement of workpieces at different distances is required.

[0024] Furthermore, the front and rear surface radii of curvature of 8 of the single lenses are both >0 and bend toward the liquid lens; the front and rear surface radii of curvature of 2 of the single lenses are both <0 and bend toward the liquid lens; the rear surface radius of curvature of 1 single lens is >0 and bends away from the liquid lens; and 1 single lens is one of a biconvex and plano-convex structure, with a front surface radius of curvature >0 and a rear surface radius of curvature <0.

[0025] In this embodiment, the optical path is further optimized by designing a specific radius of curvature, which improves the clarity and contrast of the image. At the same time, the single lens is one of a biconvex and plano-convex structure, which provides more design possibilities and helps to meet the imaging needs of different scenarios.

[0026] Furthermore, the liquid lens is driven by either electrowetting or piezoelectric actuation, with a response time ≤10ms and curvature adjustment accuracy of ±0.0001.

[0027] In this embodiment, the short response time of this design ensures that the lens can quickly adjust the depth of field to meet the real-time imaging requirements; at the same time, the high curvature adjustment accuracy enables the lens to precisely control the depth of field, improving the accuracy and stability of imaging.

[0028] Furthermore, the aperture of the lens stop is adjustable, with an adjustment range of F / #=8~12, and can be adapted to imaging needs under different lighting conditions.

[0029] In this embodiment, the adjustable aperture of the lens stop enables the lens to adapt to imaging requirements under different lighting conditions, improving the lens's versatility and flexibility; at the same time, adjusting the aperture can further optimize the imaging quality and meet the imaging requirements of specific application scenarios.

[0030] Furthermore, the optical parameters of the lens are: telecentricity <0.01°, distortion <0.5%, and depth of field ≥10mm.

[0031] In this embodiment, low telecentricity ensures uniformity and consistency of imaging, avoiding image distortion caused by changes in viewing angle; low distortion improves imaging accuracy, making the lens suitable for application scenarios with high image quality requirements; and large depth of field enables the lens to maintain clear imaging over a wide range, enhancing the lens's practicality and applicability.

[0032] Furthermore, the liquid lens dynamically adjusts the depth of field by adjusting the radius of curvature of the thin film.

[0033] In this invention, three embodiments are also provided;

[0034] Example 1:

[0035] This embodiment features an F / #=10, image square NA=0.05, image height 82mm, and a 0.3x magnification lens. It is a hybrid large depth-of-field double telecentric lens combining a glass lens and a liquid lens. Under these parameters, the depth of field of a traditional lens is 2.5mm. In this embodiment, the curvature of the liquid lens varies from -0.0007 to 0.0007, and the depth of field can reach 60mm, which is 24 times that of a traditional lens.

[0036]

[0037]

[0038] This table shows the lens parameters in Example 1, where the depth of field is 60mm, the telecentricity is <0.007 degrees, and in... Figure 3 The depth of field in Example 1 is 60mm, and the lens distortion is <0.5%.

[0039] Example 2:

[0040] This embodiment features an F / #=10, image square NA=0.05, image height 82mm, and a 0.5x magnification lens. It is a hybrid large depth-of-field double telecentric lens combining a glass lens and a liquid lens. Under these parameters, the depth of field of a traditional lens is 0.88mm. The curvature of the liquid lens in this embodiment varies from -0.0008 to 0.0008, and the depth of field can reach 40mm, which is 45 times that of a traditional lens.

[0041]

[0042]

[0043] This table shows the lens parameters in Example 2, where the depth of field is 40mm, the lens telecentricity is <0.008 degrees, and in...Figure 5 The depth of field in Example 2 is 40mm, and the lens distortion is <0.5%.

[0044] Example 3:

[0045] This embodiment features an F / #=10, image square NA=0.05, image height 82mm, and a 1x magnification glass lens and liquid lens hybrid large depth-of-field double telecentric lens. Under these parameters, the depth of field of a traditional lens is 0.22mm. In this embodiment, the curvature of the liquid lens varies from -0.0006 to 0.0006, and the depth of field can reach 10mm, which is 45 times that of a traditional lens.

[0046]

[0047]

[0048] This table shows the lens parameters in Example 3, where the depth of field is 10mm, the lens telecentricity is <0.009 degrees, and in... Figure 7 The depth of field in Example 3 is 40mm, and the lens distortion is <0.5%.

[0049] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A glass lens and liquid lens hybrid large depth of field double telecentric lens, characterized in that, comprising a glass lens group, a liquid lens and a lens diaphragm, the glass lens group is composed of 12 single lenses and 3 double cemented lenses, wherein 8 single lenses are arranged at one end of the corresponding double cemented lens, and the other 4 single lenses are arranged at the other end of the corresponding double cemented lens, wherein one double cemented lens is located on the left side of the liquid lens, and two double cemented lenses are located on the right side of the liquid lens, the liquid lens is arranged beside the lens diaphragm, and the lens object plane and the lens image plane are arranged at both ends of the lens diaphragm respectively; wherein, from the object side to the image side, the lens object plane, the first single lens, the second single lens, the third single lens, the fourth single lens, the fifth single lens, the sixth single lens, the seventh single lens, the eighth single lens, the first double cemented lens, the liquid lens, the lens diaphragm, the second double cemented lens, the third double cemented lens, the ninth single lens, the tenth single lens, the eleventh single lens, the twelfth single lens and the lens image plane are arranged in sequence; wherein the radius of curvature of the object side surface of the first single lens is greater than 0, curved towards the liquid lens, and the object side surface is convex, the radius of curvature of the object side and image side surfaces of the second single lens, the third single lens, the fourth single lens, the fifth single lens, the sixth single lens and the eighth single lens are all greater than 0, the radius of curvature of the image side surface of the seventh single lens is greater than 0, and the image side surface is concave; the radius of curvature of the object side and image side surfaces of the ninth single lens and the eleventh single lens are all less than 0, curved towards the liquid lens, the object side surface is concave, and the image side surface is convex, the radius of curvature of the image side surface of the tenth single lens is greater than 0, curved away from the liquid lens, and the image side surface is concave, the radius of curvature of the image side surface of the twelfth single lens is less than 0, curved towards the liquid lens, and the image side surface is convex; the aperture of the lens diaphragm is adjustable, the adjustment range is F / #=8~12, and it can adapt to the imaging needs under different lighting conditions; the optical parameters of the lens are telecentricity <0.01°, distortion <0.5%, and depth of field ≥10mm; the liquid lens is near the diaphragm, and the depth of field of the lens is dynamically adjusted by adjusting the radius of curvature of the film; wherein the first single lens has positive focal power; the second single lens has positive focal power; the third single lens has positive focal power; the fourth single lens has positive focal power; the eighth single lens has negative focal power; the first double cemented lens has positive focal power; the ninth single lens has negative focal power; the tenth single lens has negative focal power; the twelfth single lens has positive focal power; the combination of the focal powers of the fifth single lens, the sixth single lens, the seventh single lens, the second double cemented lens, the third double cemented lens and the eleventh single lens is positive-negative-positive-positive-negative or negative-positive-negative-negative-positive.

2. The glass lens and liquid lens hybrid large depth of field double telecentric lens according to claim 1, characterized in that, the driving mode of the liquid lens is one of electrowetting and piezoelectric driving, and the response time is ≤10ms.

Images