KR20240078789A - Small lens system - Google Patents

Abstract

The present invention relates to a small lens system consisting of a total of 7 lenses, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in order from the object side. It includes a lens, and an aperture is located between the first lens and the second lens, the first lens has a convex surface toward the object, and the second lens has positive refractive power and has a convex surface toward the object. , the third lens has a negative refractive power and a convex surface toward the object, the fourth lens has a positive refractive power and a convex surface toward the image side, and the fifth lens has a positive refractive power. , the sixth lens has a negative refractive power and a convex image side, the sixth lens has a negative refractive power and a convex image side, the seventh lens has a negative refractive power and a convex image side, the first lens All surfaces of the seventh lens are aspherical, and the axial distance (Sag value) from the center of the image side of the seventh lens to the outermost effective diameter is different in any direction, and the height of the seventh lens is Y, Sag72_30, axial distance from the center of the image side of the seventh lens to the outermost effective diameter in the 30° direction, Sag72_45, axial distance from the center of the image side of the seventh lens to the outermost effective diameter in the 45° direction, Sag72_45, center of the image side of the seventh lens The axial distance Sag72_60 from the center of the image side of the seventh lens to the outermost effective diameter in the 90° direction is Sag72_90, 0 < (Sag72_30 - Sag72_60)/Y < 0.1, 0 < ( Sag72_45 - Sag72_90)/Y < 0.1, and the refractive power P1 of the first lens is |P1| The technical point is a small lens system that satisfies <0.01. Accordingly, the present invention relates to a lens system consisting of a total of 7 lenses. By appropriately designing the refractive power and shape of the lens, it is compact and lightweight and chromatic aberration is corrected, making it easy to use in high-resolution small camera modules, especially smartphones. It can be applied, and in particular, by lowering the refractive power, it is possible to provide a small lens system with relaxed tolerances even if the TTL is short. The image side of the 7th lens has a free-form shape consisting of a rotationally asymmetric aspherical surface, which is advantageous for aberration and performance improvement. .

Description

Small lens system

The present invention relates to a small lens system consisting of a total of 7 lenses, and to a small lens system that is small and lightweight and has aberrations corrected by appropriately designing the refractive power and shape of each lens.

Recently, as the demand for high-definition, high-performance, miniaturization and lightweighting of electronic devices with camera functions, especially smartphones, has increased, research is being conducted to realize this by improving the performance of ultra-small lens optical systems.

In addition, as the zoom function of smartphones expands and foldable smartphones are released, the overall length of the lens system is becoming shorter, and high-resolution, compact, and lightweight technologies are increasingly required. Additionally, it is advantageous to miniaturize the camera by making the opening smaller, and for this purpose, it is important to reduce the size of the effective diameter of the first lens.

In particular, for small lenses mounted on smartphones, it is advantageous to have a shorter total track length of the lens system due to limitations in the thickness of the smartphone.

However, if the TTL is shortened to reduce the TTL/ImagH value, the tolerance of the lens system becomes sensitive and design errors are likely to occur, so a lens system to compensate for this is needed.

US registered patent US 10,036,876. Korean Patent No. 10-2268263.

The present invention was derived from the above necessity, and its purpose is to provide a compact lens system that is composed of a total of 7 lenses, and is small and lightweight and has aberrations corrected by appropriately designing the refractive power and shape of each lens. Do it as

The present invention is intended to achieve the above object, and includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in order from the object side, and an aperture. is located between the first lens and the second lens, the first lens has a convex surface toward the object, the second lens has positive refractive power and a convex surface toward the object, and the third lens has a convex surface toward the object. The fourth lens has a negative refractive power and a convex surface towards the object, the fourth lens has a positive refractive power and a convex surface towards the image side, and the fifth lens has a positive refractive power and a convex surface towards the image side. wherein the sixth lens has a negative refractive power and a convex surface toward the image side, and the seventh lens has a negative refractive power and a convex surface toward the image side. All surfaces are aspherical, and the axial distance (Sag) from the center of the image side of the seventh lens to the outermost effective diameter is formed differently in any direction, and the height of the seventh lens is Y, and the image side of the seventh lens is Y. Sag72_30, the axial distance from the center to the outermost effective diameter in the 30° direction, Sag72_45, the axial distance from the center of the image side of the seventh lens to the outermost effective diameter in the 45° direction, the most effective diameter in the 60° direction from the center of the image side of the seventh lens The axial distance Sag72_60 to the outer angle, and the axial distance Sag72_90 from the center of the image side of the seventh lens to the outermost effective diameter in the 90° direction are 0 < (Sag72_30 - Sag72_60)/Y < 0.1, 0 < (Sag72_45 - Sag72_90)/Y < 0.1, and the refractive power P1 of the first lens is |P1| The technical point is a small lens system that satisfies <0.01.

In addition, the center distance ct12 between the first lens and the second lens and the effective diameter outermost thickness et12 between the first lens and the second lens preferably satisfy 4 < (et12/ct12) < 10. .

In addition, the focal length F6 of the sixth lens, the focal length F7 of the seventh lens, and the effective focal length F of the entire lens system satisfy -1.5 < (F/F6) + (F/F7) < -0.5. It is desirable.

In addition, the radius of curvature R4 of the object-side surface of the second lens and the central thickness ct2 of the second lens preferably satisfy 2.2 < (R4/ct2) < 3.2.

In addition, it is preferable that the lens peripheral portions of the object-side surface and the image-side surface of the seventh lens are formed in a concave shape.

In addition, it is preferable that the center distance ct14 from the first lens to the fourth lens and the entrance pupil diameter EPD satisfy 1.2 < (EPD/ct14) < 1.4.

In addition, the Abbe number V5 of the fifth lens, the Abbe number V6 of the sixth lens, and the Abbe number V7 of the seventh lens satisfy 40 < V5 < 60, 20 < V6 < 40, and 50 < V7 < 70. It is desirable.

The present invention relates to a lens system consisting of a total of 7 lenses, and the refractive power and shape of the lens are appropriately designed to ensure that chromatic aberration is corrected while being compact and lightweight, so that it can be easily applied to high-resolution small camera modules, especially smartphones. make it possible

In particular, by lowering the refractive power, it is possible to provide a compact lens system with relaxed tolerances even if the TTL is short, and the image side of the 7th lens has a free-form shape consisting of a rotationally asymmetric aspherical surface, which is advantageous for aberration and performance improvement.

In addition, the distance from the object side of the first lens to the image surface relative to the height of the image surface is less than 1.6, making it possible to provide a lens system with a short length, making it easy to use in thin or small camera modules, especially smartphones. It was made so that it can be applied

Figure 1 - A diagram showing Embodiment 1 of a small lens system according to the present invention.
Figure 2 - A diagram showing Sag data for the image side of the seventh lens according to Example 1 of the present invention.
Figure 3 - A diagram showing an aberration diagram according to Example 1 of the present invention.
Figure 4 - A diagram showing Embodiment 2 of a miniature lens system according to the present invention.
Figure 5 - A diagram showing Sag data for the image side of the seventh lens according to Example 2 of the present invention.
Figure 6 - A diagram showing an aberration diagram according to Example 2 of the present invention.
Figure 7 - A diagram showing Embodiment 3 of a miniature lens system according to the present invention.
Figure 8 - A diagram showing Sag data for the image side of the seventh lens according to Example 3 of the present invention.
Figure 9 - A diagram showing an aberration diagram according to Example 3 of the present invention.
Figure 10 - A diagram showing Embodiment 4 of a miniature lens system according to the present invention.
Figure 11 - A diagram showing Sag data for the image side of the seventh lens according to Example 4 of the present invention.
Figure 12 - A diagram showing an aberration diagram according to Example 4 of the present invention.
Figure 13 - A reference diagram showing Sag according to the direction of the seventh lens in the lens system according to the present invention.

The present invention relates to a lens system consisting of a total of 7 lenses, in the order of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens from the object along the optical axis. It is about a small lens system arranged as follows.

In addition, by appropriately designing the refractive power and shape of the lens, it is compact and lightweight and chromatic aberration is corrected, making it easy to apply to high-resolution small camera modules, especially smartphones.

In particular, by lowering the refractive power, it is possible to provide a compact lens system with relaxed tolerances even if the TTL is short, and the image side of the seventh lens has a free-form shape composed of a rotationally asymmetric aspherical surface, which is advantageous for aberration and performance improvement.

In addition, the distance from the object side of the first lens to the image surface relative to the height of the image surface is less than 1.6, making it possible to provide a lens system with a short length, making it easy to use in thin or small camera modules, especially smartphones. It was made so that it can be applied

Hereinafter, the present invention will be described in detail with reference to the attached drawings. FIG. 1 is a diagram showing Example 1 of a small lens system according to the present invention, FIG. 2 is a diagram showing Sag data for the image side of the seventh lens according to Example 1 of the present invention, and FIG. 3 is a diagram showing Example 1 of the small lens system according to the present invention. is a diagram showing an aberration diagram according to Example 1, Figure 4 is a diagram showing Example 2 of a small lens system according to the present invention, and Figure 5 is a diagram showing the image side of the seventh lens according to Example 2 of the present invention. Figure 6 is a diagram showing Sag data for Example 2 of the present invention, Figure 7 is a diagram showing Example 3 of the small lens system according to the present invention, and Figure 8 is a diagram showing Example 3 of the small lens system according to the present invention. A diagram showing Sag data for the image side of the seventh lens according to Example 3 of , Figure 9 is a diagram showing an aberration diagram according to Example 3 of the present invention, and Figure 10 is a diagram showing the small lens system according to the present invention. This is a diagram showing Example 4, Figure 11 is a diagram showing Sag data for the image side of the seventh lens according to Example 4 of the present invention, and Figure 12 is a diagram showing an aberration diagram according to Example 4 of the present invention. 13 is a reference diagram showing Sag according to the direction of the seventh lens in the lens system according to the present invention.

As shown, the present invention includes a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), and a fifth lens (L5) arranged in order from the object side along the optical axis. ), a sixth lens (L6), and a seventh lens (L7), and the aperture is located between the first lens (L1) and the second lens (L2).

In one embodiment of the present invention, the first lens (L1) has a convex surface toward the object, the second lens (L2) has positive refractive power and a convex surface toward the object, and the third lens (L2) has a convex surface toward the object. L3) has negative refractive power and has a convex surface toward the object, the fourth lens (L4) has positive refractive power and has a convex surface toward the image side, and the fifth lens (L5) has positive refractive power. The sixth lens (L6) has a negative refractive power and has a convex surface towards the image side, and the seventh lens (L7) has a negative refractive power and has a convex surface towards the image side. It has a convex surface, and all surfaces of the first lens (L1) to the seventh lens (L7) are aspherical, and the axial distance (Sag value) from the center of the image side of the seventh lens (L7) to the outermost effective diameter is formed differently in any direction, the height of the seventh lens (L7) is Y, the axial distance from the center of the image side of the seventh lens (L7) to the outermost effective diameter in the 30° direction is Sag72_30, and the seventh lens ( Sag72_45, axial distance from the center of the image side of the 7th lens (L7) to the outermost effective diameter in the 45° direction, Sag72_60, axial distance from the center of the image side of the 7th lens (L7) to the outermost effective diameter in the 60° direction, the 7th lens (L7) The axial distance Sag72_90 from the center of the image side to the outermost effective diameter in the 90° direction satisfies 0 < (Sag72_30 - Sag72_60)/Y < 0.1, 0 < (Sag72_45 - Sag72_90)/Y < 0.1, and the first lens ( The refractive power P1 of L1) is |P1| < 0.01 is satisfied.

In this way, the lens system according to the present invention allows each lens to evenly distribute positive and negative refractive power, enabling the implementation of high performance suitable for a high-pixel small lens system.

The first lens (L1) according to an embodiment of the present invention has a convex surface toward the object and has one or more inflection points, and the refractive power P1 of the first lens (L1) is |P1| < 0.01 is satisfied.

That is, the first lens (L1) has a convex surface toward the object, which is advantageous in securing space within the barrel and improving the assembling of the lens. The central thickness is appropriately thicker than the outermost effective diameter thickness, and the refractive power is 0. It is formed close to , realizing miniaturization, and the curvature is relatively high, but the refractive power is very small, so even though the TTL is short, tolerances are relaxed and performance reproducibility is increased.

In addition, the first lens (L1) has one or more inflection points, the second lens (L2) has positive refractive power, and the lens surface is convex toward the object, so that it is very similar to the first lens (L1). It is formed to be close to each other, making it advantageous for implementing a small lens system.

And, the third lens (L3) has a negative refractive power and a convex surface toward the object, and the fourth lens (L4) has a positive refractive power and a convex surface toward the image side, and the fifth lens (L5) has a positive refractive power and has a convex surface toward the image side, the sixth lens (L6) has a negative refractive power and a convex surface toward the image side, and the seventh lens (L7) has a negative refractive power and a convex surface toward the image side. It has a refractive power and a convex surface toward the image side, and all surfaces of the first lens (L1) to the seventh lens (L7) are formed as aspherical surfaces, so that the refractive power and shape of the lens are designed appropriately, making it compact and lightweight. By correcting chromatic aberration, it can be easily applied to high-resolution small camera modules, especially smartphones.

As such, each lens forming the lens system according to the present invention has positive and negative refractive power evenly distributed and is composed of aspherical lenses, and the shape of each lens is set to be convex or concave to enable the application of a small, high-pixel lens system. Make sure it is suitable.

According to one embodiment of the present invention, the axial distance Sag of the seventh lens L7 from the center of the image side of the seventh lens L7 to the outermost effective diameter is formed differently in any direction. The image side of the seventh lens (L7) has a free-form shape made of a rotationally asymmetric aspherical surface, which is advantageous in improving aberration and performance.

According to one embodiment of the present invention, the height of the seventh lens (L7) is Y, the axial distance from the center of the image side of the seventh lens (L7) to the outermost effective diameter in the 30° direction is Sag72_30, and the seventh lens (L7) is ), axial distance Sag72_45 from the center of the image side to the outermost effective diameter in the 45° direction, Sag72_60, axial distance from the center of the image side of the seventh lens (L7) to the outermost effective diameter in the 60° direction, of the seventh lens (L7) The axial distance Sag72_90 from the center of the upper side to the outermost effective diameter in the 90° direction satisfies 0 < (Sag72_30 - Sag72_60)/Y < 0.1, 0 < (Sag72_45 - Sag72_90)/Y < 0.1.

This ensures that the height Y of the seventh lens (L7) and the axial distance from the center of the image side to the outermost effective diameter in the 30° direction, 45° direction, 60° direction, and 90° direction satisfy the above range, so that lens assembly and manufacturing Tolerances can be relaxed and it is advantageous to provide a small lens system.

In addition, the object-side and image-side surfaces of the seventh lens L7 are formed in a concave shape, which is advantageous for designing a small lens system.

In addition, the center distance ct12 between the first lens (L1) and the second lens (L2) and the effective diameter outermost thickness et12 between the first lens (L1) and the second lens (L2) according to the present invention are , 4 < (et12/ct12) < 10, which is advantageous for improving flare by increasing the distance between the first lens (L1) and the second lens (L2) on the outermost effective diameter side.

In addition, the focal length F6 of the sixth lens (L6), the focal length F7 of the seventh lens (L7), and the effective focal length F of the entire lens system are -1.5 < (F/F6) + (F/F7) < -0.5, by adjusting the refractive power of the sixth lens (L6) and the seventh lens (L7), FBL (Flange Back Length, the distance from the focus to the reference surface of the mount of the optical system) This is to reduce the length of the entire lens system. In addition, the refractive power is appropriately distributed to the sixth lens (L6) and the seventh lens (L7), thereby reducing sensitivity.

In other words, even when assembling 7 lenses, tolerance sensitivity can be relaxed, performance reproducibility is excellent, and a compact lens system with high resolution and high image quality can be provided. It is also advantageous for aberration correction and miniaturization of the lens system.

In addition, the distance TTL from the center of the first lens (L1) to the image surface and the image surface height ImageH satisfy 1.4 < TTL/ImageH < 1.6, making it possible to provide a small lens system with a short length, which can be used for thin smartphones and It is suitable for application to small electronic devices such as:

In addition, the radius of curvature R4 of the object-side surface of the second lens L2 and the central thickness ct2 of the second lens L2 satisfy 2.2 < (R4/ct2) < 3.2, thereby appropriately distributing the refractive power. And, the radius of curvature of R4 is made small to be advantageous in the design of a small lens system. This can alleviate lens manufacturing tolerances, making it advantageous for lens manufacturing, and minimizing lens thickness is advantageous for compact and lightweight lens systems.

In addition, the center distance ct14 from the first lens (L1) to the fourth lens (L4) and the diameter EPD of the entrance pupil satisfy 1.2 < (EPD/ct14) < 1.4, so by increasing the EPD, F-no By making it small, it is advantageous to design a small lens system.

In addition, the Abbe number V5 of the fifth lens (L5), the Abbe number V6 of the sixth lens (L6), and the Abbe number V7 of the seventh lens (L7) are 40 < V5 < 60, 20 < V6 < 40. , 50 < V7 < 70 is satisfied, and the Abbe number of each lens is evenly distributed to distribute power and correct chromatic aberration.

In addition, the first lens (L1) to the seventh lens (L7) are made of plastic material, and all surfaces are formed as aspherical surfaces to correct spherical aberration and chromatic aberration, and each lens is advantageous in reducing the length. It is made of a material with a refractive index, and materials with different Abbe numbers are used to help correct chromatic aberration.

As such, the present invention provides a lens system consisting of a total of 7 lenses, and the refractive power and shape of the lens are appropriately designed to ensure that chromatic aberration is corrected while being compact and lightweight, making it easy to use in high-resolution small camera modules, especially smartphones. Make it applicable.

In particular, by lowering the refractive power, it is possible to provide a compact lens system with relaxed tolerances even if the TTL is short, and the image side of the seventh lens (L7) has a free-form shape consisting of a rotationally asymmetric aspherical surface, which is advantageous for aberration and performance improvement.

In addition, the distance from the object side of the first lens (L1) to the image surface relative to the height of the image surface is less than 1.6, making it possible to provide a lens system with a short length, which can be used for thin or small camera modules, especially smartphones. It is designed to be easily applied to

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

Figure 1 shows Embodiment 1 of a small lens system according to the present invention.

As shown, from the object along the optical axis, the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), and the sixth lens (L3) The lens L6 and the seventh lens L7 are arranged in that order. The aperture is located between the first lens (L1) and the second lens (L2).

Table 1 below shows numerical data of the lenses constituting the lens system according to Example 1 of the present invention.

Side number Surface type
(cotton type) Y-radius
(Y radius of curvature) Thickness
(thickness) Glass Code
(glass code) Y Semi-Aperture
(Y semi-caliber) Object Sphere infinity 1000.0000 One Sphere infinity 0.0000 1.9414 2 Qcon Asphere 2.3558 0.4524 535000.5600 1.6600 Stop Qcon Asphere 2.2241 0.1000 1.6514 4 Qcon Asphere 2.3676 0.7935 544100.5600 1.6409 5 Qcon Asphere 29.7070 0.1000 1.5462 6 Qcon Asphere 43.6492 0.2800 670000.1940 1.5140 7 Qcon Asphere 5.8237 0.4634 1.3700 8 Qcon Asphere 19.5935 0.4791 615000.2590 1.5000 9 Qcon Asphere -172.5694 0.8000 1.6566 10 Qcon Asphere -23.8736 0.3604 535000.5600 2.3000 11 Qcon Asphere -5.7841 0.2566 2.3048 12 Qcon Asphere 6.0946 0.3997 615000.2590 2.8800 13 Qcon Asphere 5.3036 1.0013 2.7753 14 Qcon Asphere 12.9802 0.5000 535000.5600 4.5500 15 Zernike Polynomial 1.3091 0.1302 4.0173 16 Sphere infinity 0.1100 BK7_SCHOTT 4.3865 17 Sphere infinity 0.8021 4.4187 Image Sphere infinity 0.0094 4.8000

As shown in Figure 1, from the object side, the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), and the sixth lens The lens L6 and the seventh lens L7 are disposed, and the Qcon polynomial according to the Qcon aspheric surface of each lens is expressed in Equation 1 below.

where z is the sag of the plane parallel to the z axis in the lens system, c is the vertex curvature of the lens, k is the conic constant, and r is the distance from the axis of the lens ( radial distance), r _n is the normalization radius, u is r/r _n , a _m is the mth Qcon coefficient, and Q _m ^con represents the mth Qcon polynomial.

From Equation 1 above, the Qcon coefficient according to Example 1 is shown in Table 2 below.

Table 3 below shows the Zernike coefficient for the image side of the seventh lens L7 according to Example 1 based on the Zernike function (Zernike Polynomial) for the image side of the seventh lens L7.

Here, in Example 1 of the present invention, the distance TTL from the center of the first lens L1 to the image surface and the image surface height ImageH satisfy TTL/ImageH = 1.47, and the image side of the seventh lens L7 satisfies TTL/ImageH = 1.47. Axial distance from the center to the outermost effective diameter in the 30° direction Sag72_30 = -0.989042, axial distance from the image side center of the seventh lens (L7) to the outermost effective diameter in the 45° direction Sag72_45 = -0.796444, the seventh lens (L7) ) satisfies the axial distance Sag72_60 = -0.70752 from the center of the image side to the outermost effective diameter in the 60° direction, and the axial distance Sag72_90 = -0.651967 from the center of the image side of the seventh lens (L7) to the outermost effective diameter in the 90° direction. .

Figure 2 shows Sag data for the image side of the seventh lens L7 according to Example 1 of the present invention.

Table 4 below shows the (Sag72_30 - Sag72_60)/Y values and (Sag72_45 - Sag72_90)/Y values for the image side of the seventh lens of the present invention.

Height (height of the 7th lens Y) (Sag72_30 - Sag72_60)/Y (Sag72_45 - Sag72_90)/Y -4.0173 0.070076997 0.035963492 -3.6156 0.070867517 0.051839649 -3.2139 0.062239192 0.047256271 -2.8121 0.048609828 0.033839512 -2.4104 0.034096495 0.01998926 -2.0087 0.021454082 0.009851832 -1.6069 0.011961321 0.004157618 -1.2052 0.005752586 0.001730837 -0.8035 0.002277636 0.000911054 -0.4017 0.000672089 0.000487887 0 0.40173 -0.000672089 -0.000487887 0.80347 -0.002277636 -0.000911054 1.2052 -0.005752586 -0.001730837 1.60693 -0.011961321 -0.004157618 2.00866 -0.021454082 -0.009851832 2.4104 -0.034096495 -0.01998926 2.81213 -0.048609828 -0.033839512 3.21386 -0.062239192 -0.047256271 3.61559 -0.070867517 -0.051839649 4.01732 -0.070076997 -0.035963492

In addition, Embodiment 1 of the present invention has a central distance ct12 between the first lens (L1) and the second lens (L2) and an effective diameter maximum between the first lens (L1) and the second lens (L2). The outer shell thickness et12 satisfies (et12/ct12) = 4.614211449, and the focal length F6 of the sixth lens L6, the focal length F7 of the seventh lens L7, and the effective focal length F of the entire lens system are, (F/F6)+(F/F7) = -1.225985144, the radius of curvature R4 of the object-side surface of the second lens (L2), and the central thickness ct2 of the second lens (L2) are (R4/ ct2) = 2.983771963.

In addition, Embodiment 1 of the present invention satisfies the angle of view FOV = 74.26° of the lens system, satisfies the f number fno = 1.89, and includes the lens system from the first lens (L1) to the fourth lens (L4). ), the center distance to ct14, the diameter EPD of the entrance pupil satisfies (EPD/ct14) = 1.257398292, Abbe number V5 of the fifth lens (L5) = 56.00, Abbe number V6 of the sixth lens (L6) = 25.90, satisfies the Abbe number V7 = 56.00 of the seventh lens (L7).

Figure 3 shows an aberration diagram according to Example 1 of the present invention.

The first data in Figure 3 shows spherical aberration, where the horizontal axis represents the focus (mm), the vertical axis represents the image height (mm), and each graph represents the wavelength of the incident light ray. As shown, it is known that the closer the graphs are to the central vertical axis and the closer they are to each other, the better the correction of spherical aberration, and the spherical aberration of Example 1 according to the present invention is judged to be good at 0.025 mm (focus) or less. .

The second data in Figure 3 shows astigmatism, where the horizontal axis represents focus (mm), the vertical axis represents image height (mm), and the graph S represents sagittal, which is a ray incident in a horizontal direction with the lens. Graph T represents the tangential, which is a ray incident at a right angle to the lens. Here, it is known that the closer the graphs S and T are and the closer they are to the central vertical axis, the better the correction of astigmatism, and the astigmatism of Example 1 according to the present invention is judged to be good at 0.025 mm (focus) or less.

The third data in Figure 3 shows the distortion aberration. The horizontal axis represents the degree of distortion (%) and the vertical axis represents the image height (mm). It is generally known that the aberration curve is good if it is within the range of -2 to 2%, and this The optical distortion of Example 1 according to the invention is judged to be good at less than 2%.

Figure 4 shows Example 2 of a small lens system according to the present invention.

As shown, from the object along the optical axis, the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), and the sixth lens (L3) The lens L6 and the seventh lens L7 are arranged in that order. The aperture is located between the first lens (L1) and the second lens (L2).

Table 5 below shows numerical data of the lenses constituting the lens system according to Example 2 of the present invention.

Section number Surface type
(cotton type) Y-radius
(Y radius of curvature) Thickness
(thickness) Glass Code
(glass code) Y Semi-Aperture
(Y semi-caliber) Object Sphere infinity 1000.0000 One Sphere infinity 0.0000 1.9371 2 Qcon Asphere 2.3995 0.4489 535000.5600 1.6600 Stop Qcon Asphere 2.2833 0.1000 1.6505 4 Qcon Asphere 2.3958 0.7940 544100.5600 1.6467 5 Qcon Asphere 40.7353 0.1000 1.5564 6 Qcon Asphere 79.0434 0.2800 670000.1940 1.5237 7 Qcon Asphere 5.9446 0.5338 1.3700 8 Qcon Asphere 20.1828 0.4926 615000.2590 1.5000 9 Qcon Asphere -758.2389 0.6000 1.6969 10 Qcon Asphere -20.9090 0.4054 535000.5600 2.3000 11 Qcon Asphere -5.5350 0.3000 2.2380 12 Qcon Asphere 6.0288 0.3727 629737.3539 2.8800 13 Qcon Asphere 5.2175 0.8745 2.7317 14 Qcon Asphere 5.6978 0.5000 538315.6558 4.5500 15 Zernike Polynomial 1.3015 0.1799 3.7351 16 Sphere infinity 0.1100 BK7_SCHOTT 4.1596 17 Sphere infinity 1.0127 4.1986 Image Sphere infinity 0.0065 4.8000

As shown in Figure 4, from the object side, the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), and the sixth lens The lens L6 and the seventh lens L7 are disposed, and the Qcon coefficient from Equation 1 according to the Qcon aspheric surface of each lens according to Example 2 is shown in Table 6 below.

Table 7 below shows the Zernike coefficient for the image side of the seventh lens L7 according to Example 2 based on the Zernike function (Zernike Polynomial) for the image side of the seventh lens L7.

Here, in Example 2 of the present invention, the distance TTL from the center of the first lens L1 to the image surface and the image surface height ImageH satisfy TTL/ImageH = 1.48, and the image side of the seventh lens L7 satisfies TTL/ImageH = 1.48. Axial distance from the center to the outermost effective diameter in the 30° direction Sag72_30 = -0.412272, axial distance from the image side center of the seventh lens (L7) to the outermost effective diameter in the 45° direction Sag72_45 = -0.464231, the seventh lens (L7) ) satisfies the axial distance Sag72_60 = -0.511642 from the center of the image side to the outermost effective diameter in the 60° direction, and the axial distance Sag72_90 = -0.540981 from the center of the image side of the seventh lens (L7) to the outermost effective diameter in the 90° direction. .

Figure 5 shows Sag data for the image side of the seventh lens L7 according to Example 2 of the present invention.

Table 8 below shows the (Sag72_30 - Sag72_60)/Y values and (Sag72_45 - Sag72_90)/Y values for the image side of the seventh lens of the present invention.

Height (height of the 7th lens) (Sag72_30 - Sag72_60)/Y (Sag72_45 - Sag72_90)/Y -3.7351 -0.02660451 -0.020548416 -3.3616 -0.025335758 -0.016056471 -2.9881 -0.023182896 -0.013866834 -2.6146 -0.019773139 -0.012176824 -2.241 -0.015358879 -0.010047081 -1.8675 -0.010601106 -0.0073819 -1.494 -0.006271619 -0.004610343 -1.1205 -0.002976286 -0.002285538 -0.747 -0.000982576 -0.000781777 -0.3735 -0.00014993 -0.000128511 0 0.37351 0.00014993 0.000128511 0.74702 0.000982576 0.000781777 1.12052 0.002976286 0.002285538 1.49403 0.006271619 0.004610343 1.86754 0.010601106 0.0073819 2.24105 0.015358879 0.010047081 2.61456 0.019773139 0.012176824 2.98807 0.023182896 0.013866834 3.36157 0.025335758 0.016056471 3.73508 0.02660451 0.020548416

In addition, Embodiment 2 of the present invention has a central distance ct12 between the first lens (L1) and the second lens (L2), and an effective diameter maximum between the first lens (L1) and the second lens (L2). The outer shell thickness et12 satisfies (et12/ct12) = 4.510607274, and the focal length F6 of the sixth lens L6, the focal length F7 of the seventh lens L7, and the effective focal length F of the entire lens system are, (F/F6)+(F/F7) = -1.033096725, the radius of curvature R4 of the object-side surface of the second lens (L2), and the central thickness ct2 of the second lens (L2) are (R4/ ct2) = 3.017224948.

In addition, Embodiment 2 of the present invention satisfies the angle of view FOV = 73.09° of the lens system, satisfies the f number fno = 1.89, and includes the lens system from the first lens (L1) to the fourth lens (L4). ), the center distance to ct14, the diameter EPD of the entrance pupil satisfies (EPD/ct14) = 1.219357969, Abbe number V5 of the fifth lens (L5) = 56.00, Abbe number V6 of the sixth lens (L6) = 35.39, satisfies the Abbe number V7 = 65.58 of the seventh lens (L7).

Figure 6 shows an aberration diagram according to Example 2 of the present invention.

The first data in Figure 6 shows spherical aberration, where the horizontal axis represents the focus (mm), the vertical axis represents the image height (mm), and each graph represents the wavelength of the incident light ray. As shown, it is known that the closer the graphs are to the central vertical axis and the closer they are to each other, the better the correction of spherical aberration, and the spherical aberration of Example 2 according to the present invention is judged to be good at 0.025 mm (focus) or less. .

The second data in Figure 6 shows astigmatism, where the horizontal axis represents the focus (mm), the vertical axis represents the image height (mm), and the graph S represents sagittal, which is a ray incident in the horizontal direction with the lens. Graph T represents the tangential, which is a ray incident at a right angle to the lens. Here, it is known that the closer the graphs S and T are and the closer they are to the central vertical axis, the better the correction of astigmatism, and the astigmatism of Example 2 according to the present invention is judged to be good at 0.025 mm (focus) or less.

The third data in Figure 6 shows the distortion aberration. The horizontal axis represents the degree of distortion (%) and the vertical axis represents the image height (mm). It is generally known that the aberration curve is good if it is within the range of -2 to 2%, and this The optical distortion of Example 2 according to the invention is judged to be good at less than 2%.

Figure 7 shows Example 3 of a small lens system according to the present invention.

As shown, from the object along the optical axis, the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), and the sixth lens (L3) The lens L6 and the seventh lens L7 are arranged in that order. The aperture is located between the first lens (L1) and the second lens (L2).

Table 9 below shows numerical data of the lenses constituting the lens system according to Example 3 of the present invention.

Side number Surface type
(cotton type) Y-radius
(Y radius of curvature) Thickness
(thickness) Glass Code
(glass code) Y Semi-Aperture
(Y semi-caliber) Object Sphere infinity 1000.0000 One Sphere infinity 0.0000 1.9414 2 Qcon Asphere 2.5087 0.4603 535000.5600 1.6600 Stop Qcon Asphere 2.4040 0.1000 1.6512 4 Qcon Asphere 2.4301 0.7731 544100.5600 1.6402 5 Qcon Asphere 38.1731 0.1000 1.5521 6 Qcon Asphere 74.5613 0.2800 670000.1940 1.5206 7 Qcon Asphere 6.0902 0.5372 1.3700 8 Qcon Asphere 20.1087 0.5119 615000.2590 1.5000 9 Qcon Asphere 462.5181 0.5964 1.7039 10 Qcon Asphere -19.1950 0.4283 535000.5600 2.3000 11 Qcon Asphere -5.0882 0.2785 2.1992 12 Qcon Asphere 6.3619 0.3996 615000.2590 2.8800 13 Qcon Asphere 4.9687 0.7902 2.7418 14 Qcon Asphere 5.8717 0.5000 535000.5600 4.5500 15 Zernike Polynomial 1.2885 0.4246 3.8260 16 Sphere infinity 0.1100 BK7_SCHOTT 4.2017 17 Sphere infinity 0.9357 4.2410 Image Sphere infinity 0.0032 4.8000

As shown in Figure 7, from the object side, the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), and the sixth lens The lens L6 and the seventh lens L7 are disposed, and the Qcon coefficient from Equation 1 according to the Qcon aspheric surface of each lens according to Example 3 is shown in Table 10 below.

Table 11 below shows the Zernike coefficient for the image side of the seventh lens L7 according to Example 3 based on the Zernike function (Zernike Polynomial) for the image side of the seventh lens L7.

Here, in Example 3 of the present invention, the distance TTL from the center of the first lens (L1) to the image surface and the image surface height ImageH satisfy TTL/ImageH = 1.51, and the image side of the seventh lens (L7) satisfies Axial distance from the center to the outermost effective diameter in the 30° direction Sag72_30 = 0.002113, axial distance from the image side center of the seventh lens (L7) to the outermost effective diameter in the 45° direction Sag72_45 = -0.013024, the seventh lens (L7) The axial distance Sag72_60 = -0.159378 from the center of the image side to the outermost effective diameter in the 60° direction satisfies the axial distance Sag72_90 = -0.207349 from the center of the image side of the seventh lens L7 to the outermost effective diameter in the 90° direction.

Figure 8 shows Sag data for the image side of the seventh lens L7 according to Example 3 of the present invention.

Table 12 below shows the (Sag72_30 - Sag72_60)/Y values and (Sag72_45 - Sag72_90)/Y values for the image side of the seventh lens of the present invention.

Height (height of the 7th lens) (Sag72_30 - Sag72_60)/Y (Sag72_45 - Sag72_90)/Y -3.826 -0.042209198 -0.050791081 -3.4434 -0.026944534 -0.034135164 -3.0608 -0.013148639 -0.019410783 -2.6782 -0.003222715 -0.008440443 -2.2956 0.002185504 -0.001795189 -1.913 0.003815507 0.001117626 -1.5304 0.003126007 0.00156235 -1.1478 0.001635317 0.000911317 -0.7652 0.000429957 0.000201256 -0.3826 -5.4888E-05 -8.36389E-05 0 0.3826 5.4888E-05 8.36389E-05 0.76519 -0.000429957 -0.000201256 1.14779 -0.001635317 -0.000911317 1.53039 -0.003126007 -0.00156235 1.91298 -0.003815507 -0.001117626 2.29558 -0.002185504 0.001795189 2.67818 0.003222715 0.008440443 3.06077 0.013148639 0.019410783 3.44337 0.026944534 0.034135164 3.82597 0.042209198 0.050791081

In addition, Embodiment 3 of the present invention has a central distance ct12 between the first lens (L1) and the second lens (L2), and an effective diameter maximum between the first lens (L1) and the second lens (L2). The outer shell thickness et12 satisfies (et12/ct12) = 4.425864235, and the focal length F6 of the sixth lens L6, the focal length F7 of the seventh lens L7, and the effective focal length F of the entire lens system are, (F/F6)+(F/F7) = -1.06692769, the radius of curvature R4 of the object-side surface of the second lens (L2), and the central thickness ct2 of the second lens (L2) are (R4/ ct2) = 3.143121131.

In addition, Embodiment 3 of the present invention satisfies the angle of view FOV = 72.89° of the lens system, satisfies the f number fno = 1.89, and includes the first lens (L1) to the fourth lens (L4). ), the center distance to ct14, the entrance pupil diameter EPD satisfies (EPD/ct14) = 1.213589482, Abbe number V5 of the fifth lens (L5) = 56.00, Abbe number V6 of the sixth lens (L6) = 25.90, satisfies the Abbe number V7 = 56.00 of the seventh lens (L7).

Figure 9 shows an aberration diagram according to Example 3 of the present invention.

The first data in Figure 9 shows spherical aberration, where the horizontal axis represents the focus (mm), the vertical axis represents the image height (mm), and each graph represents the wavelength of the incident light ray. As shown, it is known that the closer the graphs are to the central vertical axis and the closer they are to each other, the better the correction of spherical aberration, and the spherical aberration of Example 3 according to the present invention is judged to be good at 0.025 mm (focus) or less. .

The second data in FIG. 9 shows astigmatism, where the horizontal axis represents focus (mm), the vertical axis represents image height (mm), and the graph S represents sagittal, which is a ray incident in a horizontal direction with the lens. Graph T represents the tangential, which is a ray incident at a right angle to the lens. Here, it is known that the closer the graphs S and T are and the closer they are to the central vertical axis, the better the correction of astigmatism, and the astigmatism of Example 3 according to the present invention is judged to be good at 0.025 mm (focus) or less.

The third data in Figure 9 shows the distortion aberration. The horizontal axis represents the degree of distortion (%) and the vertical axis represents the image height (mm). It is generally known that the aberration curve is good if it is within the range of -2 to 2%, and this The optical distortion of Example 3 according to the invention is judged to be good at less than 2%.

Figure 10 shows Embodiment 4 of a small lens system according to the present invention.

As shown, from the object along the optical axis, the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), and the sixth lens (L3) The lens L6 and the seventh lens L7 are arranged in that order. The aperture is located between the first lens (L1) and the second lens (L2).

The following Table 13 shows numerical data of the lenses constituting the lens system according to Example 4 of the present invention.

Section number Surface type
(cotton type) Y-radius
(Y radius of curvature) Thickness
(thickness) Glass Code
(glass code) Y Semi-Aperture
(Y semi-caliber) Object Sphere infinity 1000.0000 One Sphere infinity 0.0000 1.9544 2 Asphere 2.3521 0.3823 535000.5600 1.6600 Stop Asphere 2.2499 0.1000 1.6515 4 Asphere 2.2507 0.9217 544100.5600 1.6088 5 Asphere 24.0231 0.1736 1.4709 6 Asphere -14.8718 0.2800 670000.1940 1.4391 7 Asphere 7.9189 0.3783 1.3700 8 Asphere 12.4461 0.3878 615000.2590 1.5000 9 Qcon Asphere 152.0927 0.3165 1.5656 10 Qcon Asphere -17.8544 0.8207 544732.5143 2.3000 11 Qcon Asphere -5.5749 0.2135 2.3124 12 Qcon Asphere 5.8340 0.4738 755070.2770 2.8800 13 Qcon Asphere 5.1058 0.8251 2.8195 14 Qcon Asphere 8.3597 0.5000 539223.6550 4.5500 15 Zernike Polynomial 1.1791 0.8330 4.3222 16 Sphere infinity 0.1100 BK7_SCHOTT 4.5398 17 Sphere infinity 0.6041 4.5603 Image Sphere infinity 0.1359 4.8000

As shown in FIG. 10, from the object side, there is a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), and a sixth lens (L5). The lens L6 and the seventh lens L7 are disposed, and the Qcon coefficient from Equation 1 according to the Qcon aspheric surface of each lens according to Example 4 is shown in Table 14 below.

The following Tables 15 and 16 show the Zernike coefficient for the image side of the seventh lens (L7) according to Example 4 based on the Zernike function (Zernike Polynomial) for the image side of the seventh lens (L7). will be.

Here, in Example 4 of the present invention, the distance TTL from the center of the first lens L1 to the image surface and the image surface height ImageH satisfy TTL/ImageH = 1.55, and the image side of the seventh lens L7 satisfies TTL/ImageH = 1.55. Axial distance from the center to the outermost effective diameter in the 30° direction Sag72_30 = 0.090596, axial distance from the image side center of the seventh lens (L7) to the outermost effective diameter in the 45° direction Sag72_45 = 0.016273, of the seventh lens (L7) The axial distance from the center of the image side to the outermost effective diameter in the 60° direction satisfies Sag72_60 = -0.518565, and the axial distance from the center of the image side of the seventh lens L7 to the outermost effective diameter in the 90° direction satisfies Sag72_90 = 0.085419.

Figure 11 shows Sag data for the image side of the seventh lens (L7) according to Example 4 of the present invention.

Table 17 below shows the (Sag72_30 - Sag72_60)/Y values and (Sag72_45 - Sag72_90)/Y values for the image side of the seventh lens of the present invention.

Height (height of the 7th lens) (Sag72_30 - Sag72_60)/Y (Sag72_45 - Sag72_90)/Y -4.3222 -0.140937554 0.015997853 -3.89 -0.089900861 0.056530295 -3.4578 -0.028914929 0.076357149 -3.0255 0.0188224 0.080737877 -2.5933 0.043268424 0.072449517 -2.1611 0.045855751 0.055680826 -1.7289 0.034739791 0.035987997 -1.2967 0.019600328 0.018663306 -0.8644 0.007661599 0.007038074 -0.4322 0.001677383 0.001573269 0 0.43222 -0.001677383 -0.001573269 0.86444 -0.007661599 -0.007038074 1.29666 -0.019600328 -0.018663306 1.72888 -0.034739791 -0.035987997 2.1611 -0.045855751 -0.055680826 2.59332 -0.043268424 -0.072449517 3.02554 -0.0188224 -0.080737877 3.45776 0.028914929 -0.076357149 3.88999 0.089900861 -0.056530295 4.32221 0.140937554 -0.015997853

In addition, in Example 4 of the present invention, the center distance ct12 between the first lens (L1) and the second lens (L2), the effective diameter maximum between the first lens (L1) and the second lens (L2) The outer shell thickness et12 satisfies (et12/ct12) = 4.13069691, and the focal length F6 of the sixth lens L6, the focal length F7 of the seventh lens L7, and the effective focal length F of the entire lens system are, (F/F6)+(F/F7) = -1.226499641, the radius of curvature R4 of the object-side surface of the second lens (L2), and the central thickness ct2 of the second lens (L2) are (R4/ ct2) = 2.441817275.

In addition, Embodiment 4 of the present invention satisfies the angle of view FOV = 73.95° of the lens system, satisfies the f number fno = 1.89, and includes the first lens (L1) to the fourth lens (L4). ), the center distance to ct14, the entrance pupil diameter EPD satisfies (EPD/ct14) = 1.279312978, Abbe number V5 of the fifth lens (L5) = 51.430, Abbe number V6 of the sixth lens (L6) = 27.700, satisfies the Abbe number V7 of the seventh lens (L7) = 65.500.

Figure 12 shows an aberration diagram according to Example 4 of the present invention.

The first data in Figure 12 shows spherical aberration, where the horizontal axis represents the focus (mm), the vertical axis represents the image height (mm), and each graph represents the wavelength of the incident light ray. As shown, it is known that the closer the graphs are to the central vertical axis and the closer they are to each other, the better the correction of spherical aberration, and the spherical aberration of Example 4 according to the present invention is judged to be good at 0.025 mm (focus) or less. .

The second data in Figure 12 shows astigmatism, where the horizontal axis represents focus (mm), the vertical axis represents image height (mm), and the graph S represents sagittal, which is a ray incident in a horizontal direction with the lens. Graph T represents the tangential, which is a ray incident at a right angle to the lens. Here, it is known that the closer the graphs S and T are and the closer they are to the central vertical axis, the better the correction of astigmatism, and the astigmatism of Example 4 according to the present invention is judged to be good at 0.025 mm (focus) or less.

The third data in Figure 12 shows the distortion aberration. The horizontal axis represents the degree of distortion (%) and the vertical axis represents the image height (mm). It is generally known that the aberration curve is good if it falls within the range of -2 to 2%. The optical distortion of Example 4 according to the invention is judged to be good at less than 2%.

L1: 1st lens L2: 2nd lens
L3: Third lens L4: Fourth lens
L5: 5th lens L6: 6th lens
L7: 7th lens

Claims (7)

It includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in order from the object side, and the aperture is between the first lens and the second lens. Located in
The first lens has a convex surface toward the object,
The second lens has positive refractive power and has a convex surface toward the object,
The third lens has negative refractive power and has a convex surface toward the object,
The fourth lens has positive refractive power and has a convex surface toward the image side,
The fifth lens has positive refractive power and has a convex surface toward the image side,
The sixth lens has negative refractive power and has a convex surface toward the image side,
The seventh lens has negative refractive power and has a convex surface toward the image side,
All surfaces of the first lens to the seventh lens are aspherical, and the axial distance (Sag) from the center of the image side of the seventh lens to the outermost effective diameter is formed to be different in any direction,
The height of the seventh lens is Y, the axial distance Sag72_30 from the center of the image side of the seventh lens to the outermost effective diameter in the 30° direction, Sag72_45, the axial distance from the center of the image side of the seventh lens to the outermost effective diameter in the 45° direction. , Sag72_60, the axial distance from the center of the image side of the seventh lens to the outermost effective diameter in the 60° direction, Sag72_90, the axial distance from the center of the image side of the seventh lens to the outermost effective diameter in the 90° direction,
Satisfies 0 < (Sag72_30 - Sag72_60)/Y < 0.1, 0 < (Sag72_45 - Sag72_90)/Y < 0.1,
The refractive power P1 of the first lens is |P1| A small lens system characterized by satisfying < 0.01. The method of claim 1, wherein the center distance ct12 between the first lens and the second lens and the effective diameter outermost thickness et12 between the first lens and the second lens are,
A small lens system characterized by satisfying 4 < (et12/ct12) < 10. The method of claim 1, wherein the focal length F6 of the sixth lens, the focal length F7 of the seventh lens, and the effective focal length F of the entire lens system are,
A small lens system that satisfies -1.5 < (F/F6) + (F/F7) < -0.5. The method of claim 1, wherein the radius of curvature R4 of the object-side surface of the second lens and the central thickness ct2 of the second lens are:
A small lens system that satisfies 2.2 < (R4/ct2) < 3.2. The compact lens system according to claim 1, wherein the object-side surface and the image-side surface of the seventh lens are formed in a concave shape at the periphery of the lens. The method of claim 1, wherein the center distance ct14 from the first lens to the fourth lens and the diameter EPD of the entrance pupil are,
A small lens system characterized by satisfying 1.2 < (EPD/ct14) < 1.4. The method of claim 1, wherein the Abbe number V5 of the fifth lens, the Abbe number V6 of the sixth lens, and the Abbe number V7 of the seventh lens are:
A small lens system that satisfies 40 < V5 < 60, 20 < V6 < 40, and 50 < V7 < 70.

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