KR102491911B1 - High definition lens system - Google Patents

Abstract

The present invention relates to a wide-angle lens system composed of a total of six lenses, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side, , The first lens has a convex object-side surface and has positive refractive power, the sixth lens has a concave image-side surface, and the first to sixth lenses are all composed of aspherical surfaces, Dispersion constant V2 of the second lens, dispersion constant V4 of the fourth lens, and dispersion constant V5 of the fifth lens satisfy V2+V3+V4+V5 < 115. Accordingly, by appropriately designing the refractive power, shape, dispersion constant, etc. of the lens, it is possible to provide a compact lens system with small size and light weight, and chromatic aberration corrected, and high resolution.

Description

High definition lens system}

The present invention relates to a wide-angle lens system composed of a total of six lenses, and in particular, by appropriately designing the refractive power, shape, and dispersion constant of the lens, it is compact and lightweight, and chromatic aberration is corrected to provide a high-resolution image, It relates to a high-resolution lens system capable of obtaining wide-angle images.

Recent portable terminals are equipped with cameras to enable video calls and photo taking. In addition, as the function occupied by the camera in the portable terminal gradually increases, the demand for high resolution and wide angle of the camera for the portable terminal is gradually increasing, and there is a trend that requires miniaturization for easy portability.

In order to realize these high-definition, high-performance, and miniaturized functions, recently, a lens of a camera is made of a plastic material that is lighter than glass, and a lens system is composed of 6 or more lenses to realize high resolution.

In particular, a small lens mounted on a smart phone is advantageous as the total track length of the lens system is short due to limitations of the thickness of the smart phone.

In the case of the lens system exemplified in US Patent No. 10,241,305 shown in FIG. 1, TTL/ImagH = 1.62, which is a relationship between ImagH (height of the image plane) and TTL (distance from the front of the lens to the image plane) related to the length of the lens, compared to the height of the image plane Since the length of the lens is long (that is, the shorter the TTL/ImagH value is, the shorter the lens length is), there is a limit to its application to thin smartphones.

An object of the present invention is to provide a high-resolution lens system that provides a high-resolution image by properly designing the refractive power, shape, dispersion constant, etc. of the lens, so that the chromatic aberration is corrected while being small and lightweight. .

The present invention is to achieve the above object, and includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side, wherein the first lens The object-side surface is convex and has positive refractive power, the image-side surface of the sixth lens is concave, the first to sixth lenses are all composed of aspherical surfaces, and the dispersion constant of the second lens V2, the dispersion constant V4 of the fourth lens, and the dispersion constant V5 of the fifth lens satisfy V2+V3+V4+V5<115.

Further, it is preferable that the dispersion constant V2 of the second lens and the dispersion constant V5 of the fifth lens satisfy V2+V5<60.

In addition, it is preferable that the diameter EPD of the entrance pupil of the lens system and the height ImagH of the image plane satisfy 0.2 < EPD/ImagH < 1.0.

In addition, the dispersion constant V1 of the first lens, the dispersion constant V2 of the second lens, the dispersion constant V3 of the third lens, the dispersion constant V4 of the fourth lens, the dispersion constant V5 of the fifth lens, the dispersion constant V5 of the sixth lens The dispersion constant V6 of preferably satisfies 0.5 < (V1 + V6)/(V2 + V3 + V4 + V5) < 1.3.

The present invention relates to a lens system in which a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens are arranged from an object along an optical axis, such as refractive power, shape, dispersion constant, etc. By appropriately designing, it is possible to provide a high-resolution, high-resolution lens system that is compact and lightweight, corrects for chromatic aberration, and has a short TTL, so that it can be easily applied to a thin or small camera module, especially a smartphone.

In particular, by using a high refractive index material for the second lens, the third lens, the fourth lens, and the fifth lens, it is possible to provide a high resolution small lens system through supplementation of chromatic aberration and performance.

Figure 1 - A schematic diagram of a conventional high-resolution lens system.
Figure 2 - A diagram showing an embodiment of a high-resolution lens system according to the present invention.
3 - A diagram showing an aberration diagram according to an embodiment of the present invention.

The present invention relates to a lens system composed of a total of six lenses, and relates to a lens system arranged as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens from an object along an optical axis. will be.

In addition, by properly designing the refractive power, shape, and dispersion constant of the lens, it is compact and lightweight, and chromatic aberration is corrected, and the TTL is short, so it is a high-resolution camera module that can be easily applied to a thin or small camera module, especially a smartphone. It is to provide a high-resolution lens system.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 2 is a diagram showing an embodiment of a high-resolution lens system according to the present invention, and FIG. 3 is a diagram showing an aberration diagram according to an embodiment of 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), a fifth lens (L5) and a second lens (L5) arranged in order from the object side. It includes six lenses (L6), wherein the first lens (L1) has a convex object-side surface and has positive refractive power, and the sixth lens (L6) has a concave image-side surface. All of the first lens (L1) to the sixth lens (L6) are composed of aspherical surfaces.

This allows each lens constituting the lens system to evenly distribute positive and negative refractive powers, so that high performance suitable for a small lens system can be realized.

In particular, in the present invention, the dispersion constant V2 of the second lens L2, the dispersion constant V4 of the fourth lens L4, and the dispersion constant V5 of the fifth lens L5 satisfy V2 + V3 + V4 + V5 < 115 It is characterized by doing.

Accordingly, by using high refractive materials for the second lens (L2), the third lens (L3), the fourth lens (L4) and the fifth lens (L5), a high resolution small lens system through supplementation of chromatic aberration and performance. suitable for

In addition, according to the present invention, the dispersion constant V2 of the second lens and the dispersion constant V5 of the fifth lens satisfy V2+V5 < 60, thereby minimizing chromatic aberration and providing a high-resolution image.

In addition, in the lens system according to the present invention, the entrance pupil diameter EPD and the image plane height ImagH satisfy 0.2 < EPD/ImagH < 1.0, which is advantageous in designing a small lens system.

In addition, the dispersion constant V1 of the first lens (L1), the dispersion constant V2 of the second lens (L2), the dispersion constant V3 of the third lens (L3), the dispersion constant V4 of the fourth lens (L4), The dispersion constant V5 of the fifth lens L5 and the dispersion constant V6 of the sixth lens L6 satisfy 0.5 < (V1 + V6)/(V2 + V3 + V4 + V5) < 1.3, thereby reducing chromatic aberration. It is calibrated to provide high-resolution images.

In addition, the first to sixth lenses (L1 to L6) are formed of a plastic material, and all are formed of an aspheric surface, so that spherical aberration and chromatic aberration can be corrected, and each lens has a refractive index advantageous to reducing the length. It is formed of a material, and a material whose dispersion constant is appropriately distributed so as to be advantageous in correcting chromatic aberration is used.

As described above, the present invention relates to a lens system composed of a total of six lenses, and a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), It relates to a lens system arranged with a fifth lens (L5) and a sixth lens (L6).

Accordingly, the refractive power, shape, dispersion constant, etc. of the lens are appropriately designed so that the chromatic aberration is corrected while being compact and lightweight, and the TTL is short, so the high-resolution lens can be easily applied to a thin or small camera module, especially a smartphone. to provide the system.

In particular, by using a high refractive index material for the second lens (L2), the third lens (L3), the fourth lens (L4) and the fifth lens (L5), a high resolution small lens system through supplementation of chromatic aberration and performance. suitable for

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

<Example>

2 shows an embodiment of a high-resolution wide-angle compact lens system according to the present invention.

As shown, the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5) and the sixth lens (L5) from the object (object) along the optical axis. They are arranged in the order of the lenses L6.

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

Surface (surface number) RDY (radius of curvature) THI (thickness) Nd (refractive index) Vd (abbe number) Object Infinity 1000.00 One Infinity 0.00 2 1.90 0.79 1.5441 56.0 3 9.89 0.12 Stop Infinity 0.07 5 29.20 0.23 1.6700 19.5 6 4.95 0.30 7 10.76 0.46 1.5850 30.0 8 239.60 0.38 9 -5.66 0.34 1.6500 21.5 10 -6.78 0.47 11 6.70 0.66 1.5850 30.0 12 27.49 0.54 13 3.03 0.50 1.5350 56.0 14 1.48 0.27 15 Infinity 0.11 1.5168 64.2 16 Infinity 0.72 Image Infinity 0.00

As shown in FIG. 2, 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 When the lens L6 is disposed and the optical axis direction is set to X and the direction orthogonal to the optical axis is set to Y axis, the aspheric surface formula is as follows.

The aspherical surface is a curved surface obtained by rotating the curve obtained by the aspheric surface equation of Equation 1 around the optical axis, R is the radius of curvature, K is the conical constant, A ₃ , A ₄ , A ₅ , A ₆ , ..., A ₁₄ is an aspherical surface coefficient.

Table 2 shows the aspherical surface coefficients of the above lenses from Equation 1 above.

s2 s3 s5 s6 s7 s8 s9 s10 s11 s12 s13 s14 K -8.E-02 -7.E+00 -5.E+01 3.E+00 -9.E+01 1.E+02 -2.E+01 8.E+00 -1.E+00 1.E+02 -1.E+01 -5.E+00 A3 2.E-03 -1.E-02 -5.E-02 -4.E-02 -4.E-02 -4.E-02 3.E-02 -9.E-03 3.E-02 3.E-02 -1.E-01 -1.E-01 A4 -3.E-03 -3.E-02 1.E-01 6.E-02 -5.E-02 -2.E-02 -6.E-01 -2.E-01 -8.E-02 9.E-03 7. E-02 4.E-02 A5 2.E-02 1.E-01 -2.E-01 4.E-02 2.E-01 3.E-02 2.E+00 3.E-01 5.E-02 -4.E-02 -3.E-02 -1.E-02 A6 -6.E-02 -3.E-01 3.E-01 -2.E-01 -7.E-01 -1.E-01 -4.E+00 -4.E-01 -3.E-02 2.E-02 8. E-03 3.E-03 A7 7. E-02 4.E-01 -3.E-01 4.E-01 1.E+00 2.E-01 5.E+00 3.E-01 1.E-02 -8.E-03 -2.E-03 -3.E-04 A8 -5.E-02 -3.E-01 3.E-01 -4.E-01 -2.E+00 -3.E-01 -4.E+00 -1.E-01 -2.E-03 2.E-03 2.E-04 2.E-05 A9 2.E-02 2.E-01 -1.E-01 2.E-01 1.E+00 2.E-01 2.E+00 4.E-02 3. E-04 -2.E-04 -1.E-05 -6.E-07 A10 -5.E-03 -4.E-02 3.E-02 -7.E-02 -5.E-01 -7.E-02 -4.E-01 -5.E-03 -2.E-05 1.E-05 6.E-07 4.E-10 A11 5.E-04 5.E-03 -2.E-03 1.E-02 9.E-02 1.E-02 4.E-02 3. E-04 8. E-07 -3.E-07 -1.E-08 3. E-10

Here, the dispersion constant V2 of the second lens L2, the dispersion constant V4 of the fourth lens L4, and the dispersion constant V5 of the fifth lens L5 satisfy V2 + V3 + V4 + V5 = 101, , the dispersion constant V2 of the second lens L2 and the dispersion constant V5 of the fifth lens L5 satisfy V2+V5 =49.5, and the diameter EPD of the entrance pupil of the lens system and the image height ImagH are EPD/ ImagH = 0.601 is satisfied, and the dispersion constant V1 of the first lens L1, the dispersion constant V2 of the second lens L2, the dispersion constant V3 of the third lens L3, and the dispersion constant V3 of the fourth lens L4 The dispersion constant V4 of , the dispersion constant V5 of the fifth lens L5, and the dispersion constant V6 of the sixth lens satisfy 0.5 < (V1 + V6)/(V2 + V3 + V4 + V5) = 1.101.

3 shows an aberration diagram according to an embodiment of the present invention.

The first data of FIG. 3 represents spherical aberration, the horizontal axis represents the focal point (mm), and the vertical axis represents the image height (mm), and each graph represents the wavelength of an incident ray. As shown, it is known that the correction of spherical aberration is good as the graphs are closer to the central vertical axis and to each other, and the spherical aberration of the embodiment according to the present invention is judged to be good at 0.025 mm (focus) or less.

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

The third data in FIG. 3 shows the distortion aberration, the horizontal axis indicates distortion (%), and the vertical axis indicates image height (mm). In general, it is known that the aberration curve is good when it is within the range of -2 to 2%. As the distortion aberration of the embodiment according to the invention, optical distortion (optical distortion) is judged to be good at 2% or less.

L1: 1st lens L2: 2nd lens
L3: 3rd lens L4: 4th lens
L5: 5th lens L6: 6th lens

Claims (4)

It includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side, wherein the first lens has a convex object-side surface and positive refraction. The sixth lens has a concave image side surface, and the first to sixth lenses are all composed of aspherical surfaces,
The dispersion constant V2 of the second lens, the dispersion constant V4 of the fourth lens, and the dispersion constant V5 of the fifth lens satisfy V2+V3+V4+V5 <115;
The dispersion constant V2 of the second lens and the dispersion constant V5 of the fifth lens satisfy 49 < V2 + V5 < 60,
The entrance pupil diameter EPD and image height ImagH satisfy EPD/ImagH = 0.601,
Dispersion constant V1 of the first lens, dispersion constant V2 of the second lens, dispersion constant V3 of the third lens, dispersion constant V4 of the fourth lens, dispersion constant V5 of the fifth lens, dispersion constant of the sixth lens The constant V6 satisfies 1 < (V1 + V6) / (V2 + V3 + V4 + V5) < 1.3. delete delete delete

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