20 million pixel small lens

Abstract

The present invention relates to a 20 million pixel small lens, comprising a main lens barrel, a front lens group, an aperture, a rear lens group, and a photosensitive chip arranged at the rear end of the main lens barrel, the focal length range of the front lens group is ‑50~‑100mm, and the focal length range of the rear lens group is 6~12mm; the front lens group comprises a first lens, a second lens, and a third lens, and the rear lens group comprises a fifth lens, a sixth lens, a seventh lens, and an eighth lens, which are biconcave lenses, the second lens is a biconvex lens, the third lens is a meniscus lens, the fourth lens is a meniscus lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a biconvex lens, and the eighth lens is a meniscus lens. The present invention is used for imaging chips with more than 20 million pixels, an imaging target surface of more than 1 / 2.3 inch, and has the characteristics of large target surface and high resolution.

Description

Technical Field

[0001] The invention relates to the field of lenses, in particular to a small lens with 20 million pixels. Background Art

[0002] With the rapid development of imaging photosensitive chips, the pixels of imaging chips have made a qualitative leap. High-resolution images have two meanings for observers. One meaning is that at the same spatial resolution (when the spatial dimensions corresponding to each pixel are the same), high resolution means that a wider field of view can be seen. The other meaning is that at the same field of view, high resolution can provide more details. Both CCD and CMOS chips are developing towards high resolution. There are two ways to improve resolution: one is to increase the size of the chip wafer; the other is to reduce the pixel size to obtain more image pixels on the same area of ​​wafer.

[0003] The pixels of existing CMOS chips on the market are smaller than 1um, and the resolution is higher than 20 million, but there are very few lenses that match them. The resolution of conventional high-resolution lenses on the market is around 4K, that is, around 8 million, and the highest is around 12 million pixels, which is not enough to match the high-resolution chips. Summary of the invention

[0004] The purpose of the present invention is to provide a 20 million pixel small lens, which is used for imaging chips with more than 20 million pixels and an imaging target surface of more than 1 / 2.3 inch, and has the characteristics of large target surface and high resolution.

[0005] The present invention is implemented by the following technical scheme: A 20 million pixel small lens, characterized in that it comprises a main lens barrel, a front lens group, an aperture, a rear lens group, which are sequentially arranged in the main lens barrel along the incident direction of light, and a photosensitive chip arranged at the rear end of the main lens barrel, wherein the focal length range of the front lens group is -50 to -100 mm, and the focal length range of the rear lens group is 6 to 12 mm;

[0006] The front lens group includes a first lens, a second lens, and a third lens arranged in sequence along the incident direction of the light, and the rear lens group includes a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in sequence along the incident direction of the light, which are biconcave lenses, the second lens is a biconvex lens, the third lens is a meniscus lens, the fourth lens is a meniscus lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a biconvex lens, and the eighth lens is a meniscus lens.

[0007] The air gap between the first lens and the second lens is 0.4-0.8 mm, the air gap between the second lens and the third lens is 0.05-0.1 mm, the air gap between the third lens and the fourth lens is 0.05-0.1 mm, the air gap between the fourth lens and the aperture is 0.5-1 mm, the air gap between the aperture and the fifth lens is 0.1-0.3 mm, the fifth lens and the sixth lens form a close bonding group, the air gap between the sixth lens and the seventh lens is 0.1-0.3 mm, and the air gap between the seventh lens and the eighth lens is 3-4 mm;

[0008] Each of the lenses meets the following optical conditions:

[0009] 1R1 is -20~-35mm, 1R2 is 5~7mm, d1 is 1~2mm, N1 is 1.45~1.55, v1 is 65~82;

[0010] 2R1 is 10~15mm, 2R2 is -500~-∞, d2 is 2.5~3.5mm, N2 is 1.65~1.85, v2 is 45~55;

[0011] 3R1 is 5-8mm, 3R2 is 10-15mm, d3 is 0.5-1.2mm, N3 is 1.85-2, and v3 is 30-35;

[0012] 4R1 is 5-8mm, 4R2 is 3-4.5mm, d4 is 0.5-1mm, N4 is 1.55-1.7, and v4 is 30-38;

[0013] 5R1 is -10~-15mm, 5R2 is 5~7mm, d5 is 3~4mm, N5 is 1.7~1.785, v5 is 25~30;

[0014] 6R1 is 5~7mm, 6R2 is -10~-15mm, d6 is 1~1.5mm, N6 is 1.65~1.72, v6 is 45~55;

[0015] 7R1 is 8~10mm, 7R2 is -8~-10mm, d7 is 3~4mm, N7 is 1.53~1.7, v7 is 60~75;

[0016] 8R1 is -4 to -6mm, 8R2 is -7 to -9mm, d8 is 0.5 to 1mm, N8 is 1.5 to 1.6, and v8 is 55 to 63;

[0017] Among them, 1R1~8R1 are the curvature radii of the front end surfaces of the first lens to the eighth lens respectively, 1R2~8R2 are the curvature radii of the rear end surfaces of the first lens to the eighth lens respectively, d1~d8 are the center thicknesses of the first lens to the eighth lens respectively, N1~N8 are the refractive indices of the first lens to the eighth lens respectively, and v1~v8 are the Abbe coefficients of the first lens to the eighth lens respectively.

[0018] Preferably, the 20 million pixel small lens further includes a front pressure ring, a first spacer ring, a second spacer ring, a third spacer ring, a fourth spacer ring, and a fifth spacer ring;

[0019] The front pressing ring is fixedly connected to the external thread provided on the front part of the outer wall of the main lens barrel through its internal thread hole, and the front end of the front pressing ring is provided with a first annular inner flange protruding in the direction of the optical axis and located at the front side of the front end of the main lens barrel for limiting the front end position of the first lens; the first lens and the second lens are stacked in sequence front and back to ensure an air gap between the two;

[0020] The second spacer is fixedly installed in the body of the main lens barrel and is located between the second lens and the fifth lens to limit the axial distance between the two. The third lens, the fourth lens and the diaphragm are all installed in the body of the second spacer. The first spacer is located between the second lens and the third lens to limit the air gap between the two. The third spacer is located between the third lens and the fourth lens to limit the air gap between the two. The diaphragm is located between the fourth lens and the fifth lens. The fourth spacer is located between the sixth lens and the seventh lens to limit the air gap between the two. The fifth spacer is located between the seventh lens and the eighth lens to limit the air gap between the two. The rear end of the inner barrel wall of the main lens barrel is provided with a second annular inner flange protruding in the direction of the optical axis to limit the rear end of the eighth lens.

[0021] Preferably, the 20 million pixel small lens also includes a chip protection window arranged between the rear end of the main lens barrel and the front side of the photosensitive chip.

[0022] Compared with the previous technology, the beneficial effects of the present invention are:

[0023] 1. The present invention provides a 20 million pixel small lens, which adopts a seven-group eight-piece variant Gaussian structure, and adopts a front lens group with negative optical focal length and a rear lens group with positive optical focal length. It can be used for imaging chips with more than 20 million pixels and imaging target surfaces of more than 1 / 2.3 inches, and has the characteristics of large target surface and high resolution.

[0024] 2. The 20 million pixel small lens of the present invention further includes a front pressure ring, a first spacer ring, a second spacer ring, a third spacer ring, a fourth spacer ring, and a fifth spacer ring, which are used to ensure the fixed installation of each lens and ensure the air gap between each lens.

[0025] 3. The 20 million pixel small lens of the present invention also includes a chip protection window arranged between the rear end of the main lens barrel and the front side of the photosensitive chip, which is used to protect the photosensitive chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of a 20 million pixel small lens of the present invention;

[0027] Figure 2 This is the MTF diagram of the 20 million pixel small lens of the present invention;

[0028] Figure 3 This is a field curvature distortion diagram of a 20 million pixel small lens of the present invention;

[0029] Figure 4 This is a system aberration diagram of the 20 million pixel small lens of the present invention.

[0030] Explanation of numbers: 1-front pressure ring, 2-main lens barrel, 3-first spacer, 4-second spacer, 5-third spacer, 6-fourth spacer, 7-fifth spacer, 8-photosensitive chip, G1-first lens, G2-second lens, G3-third lens, G4-fourth lens, G5-fifth lens, G6-sixth lens, G7-seventh lens, G8-eighth lens G9-chip protection window. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the accompanying drawings:

[0032] like Figure 1-4 As shown, a 20 million pixel small lens is characterized by comprising a main lens barrel 2, a front lens group, an aperture, a rear lens group sequentially arranged in the main lens barrel 2 along the incident direction of light, and a photosensitive chip 8 arranged at the rear end of the main lens barrel 2, the focal length range of the front lens group is -50 to -100 mm, and the focal length range of the rear lens group is 6 to 12 mm;

[0033] The front lens group includes a first lens G1, a second lens G2, a third lens G3 and a fourth lens G4 arranged in sequence along the incident direction of light, and the rear lens group includes a fifth lens G5, a sixth lens G6, a seventh lens G7 and an eighth lens G8 arranged in sequence along the incident direction of light;

[0034] The first lens G1 is a biconcave lens, the second lens G2 is a biconvex lens, the third lens G3 is a meniscus lens, the fourth lens G4 is a meniscus lens, the fifth lens G5 is a biconcave lens, the sixth lens G6 is a biconvex lens, the seventh lens G7 is a biconvex lens, and the eighth lens G8 is a meniscus lens.

[0035] The air gap between the first lens G1 and the second lens G2 is 0.4-0.8 mm, the air gap between the second lens G2 and the third lens G3 is 0.05-0.1 mm, the air gap between the third lens G3 and the fourth lens G4 is 0.05-0.1 mm, the air gap between the fourth lens G4 and the aperture is 0.5-1 mm, the air gap between the aperture and the fifth lens G5 is 0.1-0.3 mm, the fifth lens G5 and the sixth lens G6 form a close cemented group, the air gap between the sixth lens G6 and the seventh lens G7 is 0.1-0.3 mm, and the air gap between the seventh lens G7 and the eighth lens G8 is 3-4 mm;

[0036] Each of the lenses meets the following optical conditions:

[0037] 1R1 is -20~-35mm, 1R2 is 5~7mm, d1 is 1~2mm, N1 is 1.45~1.55, v1 is 65~82;

[0038] 2R1 is 10~15mm, 2R2 is -500~-∞, d2 is 2.5~3.5mm, N2 is 1.65~1.85, v2 is 45~55;

[0039] 3R1 is 5-8mm, 3R2 is 10-15mm, d3 is 0.5-1.2mm, N3 is 1.85-2, and v3 is 30-35;

[0040] 4R1 is 5-8mm, 4R2 is 3-4.5mm, d4 is 0.5-1mm, N4 is 1.55-1.7, and v4 is 30-38;

[0041] 5R1 is -10~-15mm, 5R2 is 5~7mm, d5 is 3~4mm, N5 is 1.7~1.785, v5 is 25~30;

[0042] 6R1 is 5~7mm, 6R2 is -10~-15mm, d6 is 1~1.5mm, N6 is 1.65~1.72, v6 is 45~55;

[0043] 7R1 is 8~10mm, 7R2 is -8~-10mm, d7 is 3~4mm, N7 is 1.53~1.7, v7 is 60~75;

[0044] 8R1 is -4 to -6mm, 8R2 is -7 to -9mm, d8 is 0.5 to 1mm, N8 is 1.5 to 1.6, and v8 is 55 to 63;

[0045] Among them, 1R1~8R1 are the curvature radii of the front end surfaces of the first lens to the eighth lens respectively, 1R2~8R2 are the curvature radii of the rear end surfaces of the first lens to the eighth lens respectively, d1~d8 are the center thicknesses of the first lens to the eighth lens respectively, N1~N8 are the refractive indices of the first lens to the eighth lens respectively, and v1~v8 are the Abbe coefficients of the first lens to the eighth lens respectively.

[0046] Preferably, the 20 million pixel small lens further includes a front pressure ring 1, a first spacer ring 3, a second spacer ring 4, a third spacer ring 5, a fourth spacer ring 6, and a fifth spacer ring 7;

[0047] The front pressing ring 1 is fixedly connected to the external thread provided on the front part of the outer wall of the main lens barrel 2 through its internal thread hole, and the front end of the front pressing ring 1 is provided with a first annular inner flange protruding in the direction of the optical axis and located at the front side of the front end of the main lens barrel 2 for limiting the front end position of the first lens G1; the first lens G1 and the second lens G2 are stacked in sequence to ensure an air gap between the two;

[0048] The second spacer ring 4 is fixedly installed in the body of the main lens barrel 2 and is located between the second lens G2 and the fifth lens G5 to limit the axial distance between the two. The third lens G3, the fourth lens G4 and the aperture are all installed in the body of the second spacer ring 4. The first spacer ring 3 is located between the second lens G2 and the third lens G3 to limit the air gap between the two. The third spacer ring 5 is located between the third lens G3 and the fourth lens G4 to limit the air gap between the two. The aperture is located between the fourth lens G4 and the fifth lens G5; the fourth spacer ring 6 is located between the sixth lens G6 and the seventh lens G7 to limit the air gap between the two. The fifth spacer ring 7 is located between the seventh lens G7 and the eighth lens G8 to limit the air gap between the two. The rear end of the inner barrel wall of the main lens barrel 2 is provided with a second annular inner flange protruding in the direction of the optical axis for limiting the rear end of the eighth lens G8.

[0049] Preferably, the 20 million pixel small lens also includes a chip protection window G9 arranged between the rear end of the main lens barrel 2 and the front side of the photosensitive chip 8.

[0050] Figure 2 This is the MTF diagram of the 20 million pixel small lens of the present invention. It can be seen from the diagram that the resolution of the lens can reach 20 million.

[0051] Figure 3 This is a field curvature distortion diagram of the 20-megapixel small lens of the present invention, which illustrates that the field curvature of the lens is small, and the center and edge of the image can be clearly imaged at the same time.

[0052] Figure 4This is a system aberration diagram of the 20 million pixel small lens of the present invention, which illustrates that the lens has uniform aberration and small high-order spherical aberration.

[0053] The 20 million pixel small lens provided by the present invention also meets the following optical characteristics:

[0054] 1. Focal length up to 8.5mm, 2. F# up to 2.2, 3. Total optical length up to 24mm, 4. Day and night parfocal, 5. DFOV up to 53°, 6. MTF: on-axis 450lp / mm>0.3, 0.7F 300Lp / mm>0.3, 1F 220Lp / mm>0.3.

[0055] Although the present invention is illustrated and described by specific embodiments and their alternatives, it should be understood that various changes and modifications within the spirit and scope of the present invention can be implemented. Therefore, it should be understood that the present invention is not limited in any sense except by the limitations of the attached claims and their equivalents.

Claims

1. A 20 million pixel small lens, characterized by: The invention comprises a main lens barrel (2), wherein a front lens group, an aperture, and a rear lens group are sequentially arranged in the main lens barrel (2) along the incident direction of light, and a photosensitive chip (8) is also arranged on one side of the rear end of the main lens barrel (2), wherein the focal length range of the front lens group is -50 to -100 mm, and the focal length range of the rear lens group is 6 to 12 mm; The front lens group includes a first lens (G1), a second lens (G2), a third lens (G3) and a fourth lens (G4) which are sequentially arranged along the incident direction of light, and the rear lens group includes a fifth lens (G5), a sixth lens (G6), a seventh lens (G7) and an eighth lens (G8) which are sequentially arranged along the incident direction of light. The first lens (G1) is a biconcave lens, the second lens (G2) is a biconvex lens, the third lens (G3) is a meniscus lens, the fourth lens (G4) is a meniscus lens, the fifth lens (G5) is a biconcave lens, the sixth lens (G6) is a biconvex lens, the seventh lens (G7) is a biconvex lens, and the eighth lens (G8) is a meniscus lens. The air gap between the first lens (G1) and the second lens (G2) is 0.4-0.8 mm, the air gap between the second lens (G2) and the third lens (G3) is 0.05-0.1 mm, the air gap between the third lens (G3) and the fourth lens (G4) is 0.05-0.1 mm, the air gap between the fourth lens (G4) and the aperture is 0.5-1 mm, the air gap between the aperture and the fifth lens (G5) is 0.1-0.3 mm, the fifth lens (G5) and the sixth lens (G6) form a close bonding group, the air gap between the sixth lens (G6) and the seventh lens (G7) is 0.1-0.3 mm, and the air gap between the seventh lens (G7) and the eighth lens (G8) is 3-4 mm; Each of the lenses meets the following optical conditions: 1R1 is -20~-35mm, 1R2 is 5~7mm, d1 is 1~2mm, N1 is 1.45~1.55, v1 is 65~82; 2R1 is 10~15mm, 2R2 is -500~-∞, d2 is 2.5~3.5mm, N2 is 1.65~1.85, v2 is 45~55; 3R1 is 5-8mm, 3R2 is 10-15mm, d3 is 0.5-1.2mm, N3 is 1.85-2, and v3 is 30-35; 4R1 is 5-8mm, 4R2 is 3-4.5mm, d4 is 0.5-1mm, N4 is 1.55-1.7, and v4 is 30-38; 5R1 is -10~-15mm, 5R2 is 5~7mm, d5 is 3~4mm, N5 is 1.7~1.785, v5 is 25~30; 6R1 is 5~7mm, 6R2 is -10~-15mm, d6 is 1~1.5mm, N6 is 1.65~1.72, v6 is 45~55; 7R1 is 8~10mm, 7R2 is -8~-10mm, d7 is 3~4mm, N7 is 1.53~1.7, v7 is 60~75; 8R1 is -4 to -6mm, 8R2 is -7 to -9mm, d8 is 0.5 to 1mm, N8 is 1.5 to 1.6, and v8 is 55 to 63; Among them, 1R1~8R1 are the curvature radii of the front end surfaces of the first lens to the eighth lens respectively, 1R2~8R2 are the curvature radii of the rear end surfaces of the first lens to the eighth lens respectively, d1~d8 are the center thicknesses of the first lens to the eighth lens respectively, N1~N8 are the refractive indices of the first lens to the eighth lens respectively, and v1~v8 are the Abbe coefficients of the first lens to the eighth lens respectively.

2. The 20 million pixel small lens according to claim 1, characterized in that: The 20 million pixel small lens also includes a front pressure ring (1), a first spacer ring (3), a second spacer ring (4), a third spacer ring (5), a fourth spacer ring (6), and a fifth spacer ring (7); The front pressure ring (1) is fixedly connected to the external thread provided on the front part of the outer wall of the main lens barrel (2) through its internal thread hole; the front end of the front pressure ring (1) is provided with a first annular inner flange protruding in the direction of the optical axis and located in front of the front end of the main lens barrel (2) for limiting the front end position of the first lens (G1); the first lens (G1) and the second lens (G2) are stacked in sequence along the optical axis to ensure an air gap between the two; The second spacer (4) is fixedly mounted in the barrel body of the main lens barrel (2) and is located between the second lens (G2) and the fifth lens (G5) for defining the axial distance between the two lenses. The third lens (G3), the fourth lens (G4) and the diaphragm are all mounted in the barrel body of the second spacer (4). The first spacer (3) is located between the second lens (G2) and the third lens (G3) for defining the air interval between the two lenses. The third spacer (5) is located between the third lens (G3) and the fourth lens (G4) for defining the air interval between the two lenses. The diaphragm is located between the fourth lens (G4) and the fifth lens (G5). The fourth spacer (6) is located between the sixth lens (G6) and the seventh lens (G7) for defining the air interval between the two lenses. The fifth spacer (7) is located between the seventh lens (G7) and the eighth lens (G8) for defining the air interval between the two lenses. The rear end of the inner barrel wall of the main lens barrel (2) is provided with a second annular inner flange protruding in the direction of the optical axis for limiting the rear end of the eighth lens (G8).

3. The 20 million pixel small lens according to claim 1, characterized in that: The 20 million pixel small lens also includes a chip protection window (G9) arranged between the rear side of the eighth lens (G8) and the front side of the photosensitive chip (8).

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