Video conference camera

Abstract

The present invention discloses a video conferencing lens, which is composed of a first concave-convex negative lens, a second concave-convex negative lens, a first biconvex positive lens, a third concave-convex negative lens, a second biconvex positive lens, a meniscus positive lens, a meniscus negative lens, a third biconvex positive lens, a fourth concave-convex negative lens, and a flat protective glass. The present invention has a diagonal imaging field of view of 90°, achieving wide-angle imaging. While maintaining excellent performance in various indicators, the first lens has an aperture of 10 mm and a total system length of 20.7 mm, facilitating optical and mechanical integration in practical applications of the video conferencing lens. Aberration correction over a wide field of view is achieved using only two even-order aspheric surfaces plus a spherical surface, and vertical axis chromatic aberration can be corrected to within the Airy disk, resulting in low cost and excellent chromatic aberration correction capabilities.

Description

Technical Field

[0001] The present invention relates to the technical field of video lenses, and in particular to a video conferencing lens. Background Art

[0002] Due to irresistible factors such as distance, the widespread use of video conferencing is an inevitable development of current network technology. Video conferencing provides audio and video support for various business and academic conferences under remote conditions, reducing the cost and risk of business trips and saving unnecessary physical expenditure. Currently, the video conferencing lenses on the market, such as the high-definition video conferencing lens designed by Cao Laishu and others, use a 9-element glass-plastic hybrid design, 4 of which are aspherical, and the effective aperture of the first lens is 18 mm , aperture value F is 2.1, and the system focal length is 4.35 mm ≤ f ≤4.46 mm , diagonal field of view DFOV At around 90°, the total length of the system is less than 31 mm , relative illumination is greater than 40%. The research results show that the spatial frequency is 167 lp / mm The modulation transfer function at 0° field of view is 0.648, the modulation transfer function at 45° field of view is 0.34, and the absolute value of optical distortion is less than 2%. This matches the pixel size of 2.9μ. m 1 / 2.8 inch of CCD Image sensor. However, the first lens element of this lens has a larger aperture and the overall length of the system is longer, both of which can be further optimized. In addition, this lens can reduce the use of aspherical surfaces to reduce costs and further optimize the vertical axis chromatic aberration of the entire band to within the Airy disk, ensuring the color authenticity of the full-band projection image. Summary of the Invention

[0003] The present invention aims to solve the shortcomings of existing video conferencing lenses and provide a video conferencing lens with a small aperture, a large field of view and high image quality.

[0004] To solve the above problems, the present invention is achieved through the following technical solutions:

[0005] The video conferencing lens is composed of a first concave-convex negative lens, a second concave-convex negative lens, a first biconvex positive lens, a concave-convex positive lens, a second biconvex positive lens, a meniscus positive lens, a meniscus negative lens, a third biconvex positive lens, a fourth concave-convex negative lens, and a flat protective glass. The first concave-convex negative lens is a single lens with a front surface curvature radius of r 1 is 110 mm ≤ r 1≤140 mm , back surface curvature radiusr 2 is 29 mm ≤ r 2 ≤ 33 mm , center thickness of front and rear surfaces d 1 is 0.45 mm ≤ d 1 ≤ 0.65 mm , D Refractive index under light n d1 is 1.7 ≤ n d1 ≤ 1.9, D Abbe number under light v d1 is 21 ≤ v d1 ≤ 24. The second biconvex negative lens is a single lens, the radius of curvature of the front surface r 3 is 27 mm ≤ r 3 ≤ 31 mm , the radius of curvature of the rear surface r 4 is 3 mm ≤ r 4 ≤ 4 mm , center thickness of front and rear surfaces d 2 is 0.4 mm ≤ d 2 ≤ 0.6 mm , D Refractive index under light n d2 is 1.6 ≤ n d2 ≤ 1.8, D Abbe number under light v d2 is 49 ≤ v d2 ≤ 52. The first biconvex positive lens and the biconcave positive lens constitute a double cemented lens; the first biconvex positive lens, the radius of curvature of the front surface r 5 is 10 mm ≤ r 5 ≤ 14 mm , the radius of curvature of the rear surface r 6 is -940 mm ≤ r 6 ≤ -900 mm , center thickness of front and rear surfaces d 3 is 1.5 mm ≤ d 3 ≤ 1.7 mm , D Refractive index under light n d3 is 1.7 ≤ n d3 ≤ 1.8,D Abbe number under light v d3 is 26 ≤ v d3 is 28; convex positive lens, radius of curvature of front surface r 6 is -940 mm ≤ r 6 ≤ -900 mm , radius of curvature of back surface r 7 is -48 mm ≤ r 7 ≤ -44 mm , center thickness of front and back surfaces d 4 is 1.5 mm ≤ d 4 ≤ 1.7 mm , D refractive index under light n d4 is 1.6 ≤ n d4 ≤ 1.7, D Abbe number under light v d4 is 54 ≤ v d4 ≤ 56. Second biconvex positive lens and meniscus positive lens are combined into a doublet; second biconvex positive lens, radius of curvature of front surface r 8 is 3 mm ≤ r 8 ≤ 4 mm , radius of curvature of back surface r 9 is -6 mm ≤ r 9 ≤ -5 mm , center thickness of front and back surfaces d 5 is 0.8 mm ≤ d 5 ≤ 1.1 mm , D refractive index under light n d5 is 1.4 ≤ n d5 ≤ 1.5, D Abbe number under light v d5 is 75 ≤ v d5 ≤ 85; meniscus negative lens, radius of curvature of front surface r 9 is -6 mm ≤ r 9 ≤ -5 mm , radius of curvature of back surface r 10 is -6 mm ≤ r10 ≤ -5 mm , center thickness of front and rear surfaces d 6 is 0.7 mm ≤ d 6 ≤ 0.99 mm , D refractive index under light n d1 is 1.4 ≤ n d6 ≤ 1.5, D Abbe number under light v d6 is 60 ≤ v d6 ≤ 70. The meniscus negative lens is a single lens, the radius of curvature of the front surface r 11 is -5 mm ≤ r 11 ≤ -4 mm , the radius of curvature of the rear surface r 12 is -11 mm ≤ r 12 ≤ -9 mm , center thickness of front and rear surfaces d 7 is 1.1 mm ≤ d 7 ≤ 1.3 mm , D refractive index under light n d7 is 1.7 ≤ n d7 ≤ 1.8, D Abbe number under light v d7 is 25 ≤ v d7 ≤ 28. The third biconvex positive lens is a single lens, the radius of curvature of the front surface r 13 is 5 mm ≤ r 13 ≤ 7 mm , the radius of curvature of the rear surface r 14 is -11 mm ≤ r 14 ≤ -9 mm , center thickness of front and rear surfaces d 8 is 0.8 mm ≤ d 8 ≤ 1 mm , D refractive index under light n d8is 1.7<= n d8 <=1.8, D Abbe number under light v d8 is 50<= v d8 <=53. The fourth meniscus negative lens is a single lens, the radius of curvature of the front surface r 15 is 15 mm <= r 15 <=18 mm , the radius of curvature of the rear surface r 16 is 2 mm <= r 16 <=3 mm , the central thickness of the front and rear surfaces d 9 is 0.5 mm <= d 9<=0.7 mm , D refractive index under light n d9 is 1.8<= n d9 <=1.9, D Abbe number under light v d9 is 21<= v d9 <=24.

[0006] In the above scheme, the first meniscus negative lens, the second meniscus negative lens, the first double convex positive lens, the meniscus positive lens, the second double convex positive lens, the crescent positive lens, the crescent negative lens, the third double convex positive lens, and the fourth meniscus negative lens are all glass lenses.

[0007] In the above scheme, the first meniscus negative lens and the third double convex positive lens are double-sided even aspheric lenses.

[0008] In the above scheme, the flat protective glass is H - K 9 flat glass.

[0009] Compared with the prior art, the present application has the following characteristics:

[0010] 1. The diagonal imaging field of view of the present application is 90°, realizing wide-angle field of view imaging.

[0011] 2. Under the premise of excellent indicators, the maximum lens aperture of the present application is 10 mm , and the total length of the system is 20.7 mm , which is conducive to the use of optical and mechanical integration in the actual application of the video conference lens.

[0012] 3. The present invention uses only two even-order aspheric surfaces + a spherical surface to achieve large-field aberration correction, and the vertical axis chromatic aberration can be corrected to within the Airy disk, with low cost and excellent chromatic aberration correction capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] mm This is a structural diagram of the video conferencing lens of the present invention.

[0014] mm The video conferencing lens of the present invention mm curve chart.

[0015] mm This is a diagram of vertical axial chromatic aberration of the video conferencing lens of the present invention.

[0016] mm is the field curvature and distortion diagram of the video conferencing lens of the present invention, ( a ) Field curvature diagram, ( b ) distortion map.

[0017] mm This is a relative illumination diagram of the video conferencing lens of the present invention.

[0018] Markings in the figure: 1-first concave-convex negative lens, 2-second concave-convex negative lens, 3-first biconvex positive lens, 4-concave-convex positive lens, 5-second biconvex positive lens, 6-meniscus positive lens, 7-meniscus negative lens, 8-third biconvex positive lens, 9-fourth concave-convex negative lens, 10-flat protective glass. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific examples.

[0020] In order to realize the design of high-standard video conferencing lens with small aperture, large field of view, low cost and high color authenticity, the video conferencing lens proposed in the present invention is as follows: mm As shown, it mainly consists of, arranged from front to back, a first meniscus negative lens 1, a second meniscus negative lens 2, a first biconvex positive lens 3, a meniscus positive lens 4, a second biconvex positive lens 5, a meniscus positive lens 6, a meniscus negative lens 7, a third biconvex positive lens 8, a fourth meniscus negative lens 9, and a flat protective glass 10. The first meniscus negative lens 1 and the third biconvex positive lens 8 are double-sided even-order aspheric lenses used to correct large-field aberrations.

[0021] The first meniscus negative lens 1 is a single lens, and the curvature radius of the front surface is r 1 is 110 mm ≤ r 1≤140 mm , back surface curvature radius r2 is 29 mm ≤ r 2 is 33 mm , center thickness of front and rear surfaces d 1 is 0.45 mm ≤ d 1 is 0.65 mm , D refractive index under light n d1 is 1.7 ≤ n d1 ≤ 1.9, D Abbe number under light v d1 is 21 ≤ v d1 ≤ 24.

[0022] The second concave-convex negative lens 2 is a single lens, the radius of curvature of the front surface r 3 is 27 mm ≤ r 3 is 31 mm , the radius of curvature of the rear surface r 4 is 3 mm ≤ r 4 is 4 mm , center thickness of front and rear surfaces d 2 is 0.4 mm ≤ d 2 is 0.6 mm , D refractive index under light n d2 is 1.6 ≤ n d2 ≤ 1.8, D Abbe number under light v d2 is 49 ≤ v d2 ≤ 52.

[0023] The first double-convex positive lens 3 and the concave-convex positive lens 4 constitute a doublet cemented lens. The first double-convex positive lens 3, the radius of curvature of the front surface r 5 is 10 mm ≤ r 5 is 14 mm , the radius of curvature of the rear surface r 6 is -940 mm ≤ r 6 is -900 mm , center thickness of front and rear surfaces d 3 is 1.5 mm ≤ d 3 is 1.7 mm , D refractive index under light nd3 1.7≤ n d3 ≤1.8, D Abbe number under light v d3 26≤ v d3 ≤28. Concave-convex positive lens, curvature radius of the front surface r 6 is -940 mm ≤ r 6≤-900 mm , back surface curvature radius r 7 is -48 mm ≤ r 7≤-44 mm , the center thickness of the front and rear surfaces d 4 for 1.5 mm ≤ d 4≤1.7 mm , D Refractive index under light n d4 1.6≤ n d4 ≤1.7, D Abbe number under light v d4 54≤ v d4 ≤56.

[0024] The second biconvex positive lens 5 and the meniscus positive lens 6 are combined into a double cemented lens. The curvature radius of the front surface of the second biconvex positive lens 5 is r 8 to 3 mm ≤ r 8≤4 mm , the curvature radius of the rear surface r 9 is -6 mm ≤ r 9≤-5 mm , the center thickness of the front and rear surfaces d 5 is 0.8 mm ≤ d 5≤1.1 mm , D Refractive index under light n d5 1.4≤ n d5 ≤1.5, D Abbe number under light v d5 75≤ v d5 ≤85. Meniscus negative lens 7, the radius of curvature of the front surface r 9 is -6 mm ≤ r 9≤-5mm radius of curvature of the back surface r 10 -6 mm ≤ r 10 -5 mm center thickness of the front and back surfaces d 6 is 0.7 mm ≤ d 6 is 0.99 mm , D refractive index under light n d1 1.4 n d6 1.5, D Abbe number under light v d6 60 v d6 70.

[0025] Meniscus negative lens 7 is a single lens, the radius of curvature of the front surface r 11 -5 mm ≤ r 11 -4 mm radius of curvature of the back surface r 12 -11 mm ≤ r 12 -9 mm center thickness of the front and back surfaces d 7 is 1.1 mm ≤ d 7 is 1.3 mm , D refractive index under light n d7 1.7 n d7 1.8, D Abbe number under light v d7 25 v d7 28.

[0026] Third bi-convex positive lens 8 is a single lens, the radius of curvature of the front surface r 13 5 mm ≤ r 13 7 mm radius of curvature of the back surface r 14 -11 mm ≤ r 14≤-9 mm , the center thickness of the front and rear surfaces d 8 is 0.8 mm ≤ d 8≤1 mm , D Refractive index under light n d8 1.7≤ n d8 ≤1.8, D Abbe number under light v d8 50≤ v d8 ≤53.

[0027] The fourth meniscus negative lens 9 is a single lens, and the curvature radius of the front surface is r 15 15 mm ≤ r 15 ≤18 mm , the curvature radius of the rear surface r 16 is 2 mm ≤ r 16 ≤3 mm , the center thickness of the front and rear surfaces d 9 is 0.5 mm ≤ d 9≤0.7 mm , D Refractive index under light n d9 1.8≤ n d9 ≤1.9, D Abbe number under light v d9 21≤ v d9 ≤24.

[0028] Flat protective glass 10 is H - K 9. Flat glass.

[0029] Can be matched with mm The company's image sensors mm 9286, pixel size is 3μ m ×3μ m , resolution is 1344 mm ×1136 mm , the main ray incident angle is 29.7°, achieving 1.52 million pixel imaging. The video conferencing lens consists of 11 glass lenses and rear protection. The final design achieves a system focal length of 3.19 mm ,systemF The number is 2.0, the diagonal field of view mm is 90°, and the full image height is 6 mm , the maximum incident angle of the main ray on the image plane is 29.7°, and the total length of the system is 20.7 mm , lens back focus distance 3.82 mm , only two pieces of even-order aspheric design, low processing cost, excellent lens index. Video conferencing lens data table is shown in Table 1. Aspheric coefficient is shown in Table 2. k is the cone coefficient, A 4~ A 16 is the coefficient of each high-order term of the even-order aspheric surface.

[0030] Table 1 Video conferencing lens data sheet

[0031] mm mm mm mm mm mm mm mm mm mm 1 mm 128.010 0.590 1.846 23.787 2 mm 31.820 0.429 3 mm 29.554 0.500 1.746 51.009 4 mm 3.732 4.573 5 mm 12.781 1.669 1.755 27.547 6 mm -928.176 1.669 1.611 55.813 7 mm -46.868 2.180 mm mm 3.865 0.977 1.497 81.615 9 mm -5.120 0.806 1.470 66.885 10 mm -5.863 0.168 11 mm -4.899 1.256 1.755 27.547 12 mm -9.817 0.444 13 mm 5.514 0.859 1.734 51.494 14 mm -9.380 0.100 15 mm 17.231 0.633 1.846 23.787 16 mm 2.977 3.047 17 mm mm 0.400 1.516 64.212 18 mm mm 0.376 mm mm mm

[0032] Table 2 Aspheric coefficients of video conferencing lens

[0033] mm 4 6 8 10 12 14 16 1 87.108 8.621-004 1.412-005 1.759-007 -4.380-008 -2.488-009 3.574-010 -8.062-012 2 43.658 4.071-004 3.551-005 -9.640-007 -1.319-007 -8.593-010 1.003-009 -3.361-011 13 -3.311 -4.587-003 -3.340-004 -7.804-006 -1.036-004 8.100-006 4.017-006 -7.845-007 14 0.328 -5.318-004 -3.594-004 -1.801-004 6.911-007 1.815-006 2.532-007 -1.608-007

[0034] mm The video conferencing lens of the present invention mm As can be seen from the curve, at the 1 / 2 cutoff frequency, the central field of view modulation transfer function is better than 68%, the field of view modulation transfer function within 0.7 is better than 63%, and the full field of view modulation transfer function is better than 34%. lp / mm The full-field modulation transfer function is better than 20%, and the video conferencing lens optical system has excellent image quality.

[0035] mm This is the vertical axis chromatic aberration diagram of the video conferencing lens of the present invention. As can be seen from the figure, the maximum vertical axis chromatic aberration of the field of view is less than 3μ m , within the Airy disk range (double dashed line in the figure), a high degree of chromatic aberration correction is achieved.

[0036] mm The field curvature and distortion diagram of the video conferencing lens of the present invention is shown in the figure. As can be seen from the figure, the maximum field curvature of the entire field of view is less than 0.07 mm , the maximum distortion is -4.98%, and the human eye cannot observe obvious image deformation. The optical system has strong aberration correction capability.

[0037] mm This is a relative illumination diagram of the video conferencing lens of the present invention. As can be seen from the figure, the illumination ratio of each field of view relative to the illumination of the 0° field of view, and the relative illumination of the entire field of view are all better than 41%.

[0038] In summary, the present application puts the diaphragm in the middle, increases the symmetry of the system, the front group is two negative lenses + double cementation form for receiving large field of view, and the rear group is double cementation + negative lens + positive lens + negative lens form. First, eight lenses are designed in aspheric form, through mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm + spot radius + centroid optimization, hammer type optimization and other operations to realize high mark video conference lens design.

[0039] It should be noted that although the above embodiments of the present application are illustrative, this is not a limitation of the present application, therefore the present application is not limited to the above specific embodiments. Without departing from the principles of the present application, any other embodiments obtained by those skilled in the art under the inspiration of the present application are considered to be within the protection of the present application.

Claims

1. Video conferencing lens, which is characterized by, The invention is composed of a first concave-convex negative lens (1), a second concave-convex negative lens (2), a first biconvex positive lens (3), a concave-convex positive lens (4), a second biconvex positive lens (5), a meniscus positive lens (6), a meniscus negative lens (7), a third biconvex positive lens (8), a fourth concave-convex negative lens (9), and a flat protective glass (10) which are arranged in sequence from front to back; the first concave-convex negative lens (1), the second concave-convex negative lens (2), the first biconvex positive lens (3), the concave-convex positive lens (4), the second biconvex positive lens (5), the meniscus positive lens (6), the meniscus negative lens (7), the third biconvex positive lens (8), and the fourth concave-convex negative lens (9) are all glass lenses; the flat protective glass (10) is H - K 9. Plate glass; The first concave-convex negative lens (1) is a single lens, and the curvature radius of the front surface is r 1 is 110 mm ≤ r 1≤140 mm , back surface curvature radius r 2 is 29 mm ≤ r 2≤33 mm , the center thickness of the front and rear surfaces d 1 is 0.45 mm ≤ d 1≤0.65 mm , D Refractive index under light n d1 1.7≤ n d1 ≤1.9, D Abbe number under light v d1 21≤ v d1 ≤24; The second concave-convex negative lens (2) is a single lens, and the curvature radius of the front surface is r 3 is 27 mm ≤ r 3≤31 mm , the radius of curvature of the rear surface r 4 for 3 mm ≤ r 4≤4 mm , the center thickness of the front and rear surfaces d 2 is 0.4 mm ≤ d 2≤0.6 mm , D Refractive index under light n d2 1.6≤ n d2 ≤1.8, D Abbe number under light v d2 49≤ v d2 ≤52; The first biconvex positive lens (3) and the concave-convex positive lens (4) form a double cemented lens; the first biconvex positive lens (3) has a front surface curvature radius of r 5 out of 10 mm ≤ r 5≤14 mm , the radius of curvature of the rear surface r 6 is -940 mm ≤ r 6≤-900 mm , the center thickness of the front and rear surfaces d 3 is 1.5 mm ≤ d 3≤1.7 mm , D Refractive index under light n d3 1.7≤ n d3 ≤1.8, D Abbe number under light v d3 26≤ v d3 ≤28; concave-convex positive lens, front surface curvature radius r 6 is -940 mm ≤ r 6≤-900 mm , back surface curvature radius r 7 is -48 mm ≤ r 7≤-44 mm , the center thickness of the front and rear surfaces d 4 to 1.5 mm ≤ d 4≤1.7 mm , D Refractive index under light n d4 1.6≤ n d4 ≤1.7, D Abbe number under light v d4 54≤ v d4 ≤56; The second biconvex positive lens (5) and the meniscus positive lens (6) are combined into a double cemented lens; the curvature radius of the front surface of the second biconvex positive lens (5) is r 8 to 3 mm ≤ r 8≤4 mm , the radius of curvature of the rear surface r 9 is -6 mm ≤ r 9≤-5 mm , the center thickness of the front and rear surfaces d 5 is 0.8 mm ≤ d 5≤1.1 mm , D Refractive index under light n d5 1.4≤ n d5 ≤1.5, D Abbe number under light v d5 75≤ v d5 ≤85; Meniscus negative lens (7), radius of curvature of the front surface r 9 is -6 mm ≤ r 9≤-5 mm , back surface curvature radius r 10 -6 mm ≤ r 10 ≤-5 mm , the center thickness of the front and rear surfaces d 6 is 0.7 mm ≤ d 6≤0.99 mm , D Refractive index under light n d1 1.4≤ n d6 ≤1.5, D Abbe number under light v d6 60≤ v d6 ≤70; The meniscus negative lens (7) is a single lens with a front surface curvature radius of r 11 -5 mm ≤ r 11 ≤-4 mm , the radius of curvature of the rear surface r 12 -11 mm ≤ r 12 ≤-9 mm , the center thickness of the front and rear surfaces d 7 for 1.1 mm ≤ d 7≤1.3 mm , D Refractive index under light n d7 1.7≤ n d7 ≤1.8, D Abbe number under light v d7 25≤ v d7 ≤28; The third biconvex positive lens (8) is a single lens, and the curvature radius of the front surface is r 13 5 mm ≤ r 13 ≤7 mm , the radius of curvature of the rear surface r 14 -11 mm ≤ r 14 ≤-9 mm , the center thickness of the front and rear surfaces d 8 is 0.8 mm ≤ d 8≤1 mm , D Refractive index under light n d8 1.7≤ n d8 ≤1.8, D Abbe number under light v d8 50≤ v d8 ≤53; The fourth concave-convex negative lens (9) is a single lens, and the curvature radius of the front surface is r 15 15 mm ≤ r 15 ≤18 mm , the radius of curvature of the rear surface r 16 is 2 mm ≤ r 16 ≤3 mm , the center thickness of the front and rear surfaces d 9 is 0.5 mm ≤ d 9≤0.7 mm , D Refractive index under light n d9 1.8≤ n d9 ≤1.9, D Abbe number under light v d9 21≤ v d9 ≤24.

2. The video conferencing lens according to claim 1, characterized in that: The first concave-convex negative lens (1) and the third biconvex positive lens (8) are double-sided even aspherical lenses.

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