KR101140307B1 - Optical system - Google Patents

Abstract

An imaging optical system is disclosed. The imaging optical system includes: a first lens having positive refractive power and having one surface convex on an object side; A second lens having positive refractive power and having one surface opposite the first lens convex; A third lens having negative refractive power and one surface opposite the second lens being concave; A fourth lens having positive refractive power and a meniscus shape in which one surface opposite the third lens is convex and at least one surface is aspheric; And a fifth lens having a negative refractive power and an aspherical surface having one surface opposite to the fourth lens and one surface opposite to the fourth lens having an inflection point, wherein the first lens, the second lens, and the first lens Each of the three lenses, the fourth lens, and the fifth lens are spaced apart from each other and sequentially arranged from the object side toward the image side.

Description

Imaging optical system {OPTICAL SYSTEM}

The present invention relates to an imaging optical system.

Cameras installed in mobile phones demand performance similar to those of electronic still cameras, but require miniaturization, light weight, and low cost for photographic lenses. Image sensors, such as CCD and CMOS, which are being used in recent years, are increasing in size while the pixel size is getting smaller, and the imaging optical system using such an image sensor requires high resolution.

In addition, in order to satisfy the miniaturization and cost reduction, the photographing lens mounted on the camera of mobile phone, PC, etc. should reduce the number of lenses as much as possible. Becomes difficult.

Therefore, there is a need for an imaging optical system that can realize high resolution and can be miniaturized.

SUMMARY OF THE INVENTION The present invention provides an imaging optical system with high resolution while miniaturization is possible.

According to an aspect of the invention, the first lens having a positive refractive power and one surface of the object side is convex; A second lens having positive refractive power and having one surface opposite the first lens convex; A third lens having negative refractive power and one surface opposite the second lens being concave; A fourth lens having positive refractive power and a meniscus shape in which one surface opposite the third lens is convex and at least one surface is aspheric; And a fifth lens having a negative refractive power and an aspherical surface having one surface opposite to the fourth lens and one surface opposite to the fourth lens having an inflection point, wherein the first lens, the second lens, and the first lens Each of the three lenses, the fourth lens, and the fifth lens are spaced apart from each other, and are sequentially arranged from the object side toward the image side, and the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are sequentially disposed. The lens is provided with an imaging optical system that satisfies the following Conditional Expressions 1 and 2.

[Condition 1] 1.1 <tt / f <1.5, 0.4 <f12 / f <0.8, [Condition 2] 50> V _g1 -V _{g 3} > 25, V _g1 -V _g4 | <15, V _{g 4-} V _{g 5} | <15 where tt: distance from one surface of the first lens to the image sensor on the optical axis, ｆ: composite focal length of the first lens, the second lens, the third lens, the fourth lens and the fifth lens, # 12: composite focal length of the first lens and the second lens, V _g1 : Abbe number of the first lens, V _{g 3} : Abbe number of the third lens, V _g4 : Abbe number of the fourth lens, V _{g 5} : Abbe's number of the fifth lens

In addition, the fourth lens and the fifth lens may satisfy the following Conditional Expressions 3 and 4. [Condition Formula 3] | A4 |> 1.5 * 10 ^-5 , [Condition Formula 4] | A5 |> 1.5 * 10 ^-5 , where A4: coefficient of linear thermal expansion of the fourth lens, A5: coefficient of linear thermal expansion of the fifth lens

In addition, an aperture may be provided on the object side of the first lens.

In addition, the fifth lens may have a shape in which the other surface of the fourth lens is concave.

In addition, the second lens may be a double-sided aspherical surface.

In addition, the first lens may be a double-sided aspherical surface.

According to the embodiment of the present invention, the imaging optical system is made smaller and can be suitable for a camera such as a mobile phone, a PC, and the like because of its high resolution.

1 is a lens configuration of an imaging optical system according to a first embodiment of the present invention.
FIG. 2 is a view of aberration diagram according to the first embodiment shown in FIG. 1; FIG.
3 is a view showing a resolution in accordance with the first embodiment shown in FIG.
4 is a diagram showing lateral color values according to the first embodiment shown in FIG. 1;
5 is a lens configuration diagram of an imaging optical system according to a second embodiment of the present invention.
FIG. 6 is a view of a fifth aberration diagram according to the second embodiment shown in FIG. 5; FIG.
FIG. 7 is a view showing the resolution according to the second embodiment shown in FIG.
FIG. 8 is a diagram showing lateral color values according to the second embodiment shown in FIG. 5; FIG.
9 is a lens configuration diagram of an imaging optical system according to a third embodiment of the present invention.
FIG. 10 is a view showing a fifth aberration diagram according to the third embodiment shown in FIG. 9; FIG.
FIG. 11 is a view showing the resolution according to the third embodiment shown in FIG.
FIG. 12 is a diagram showing lateral color values according to the third embodiment shown in FIG. 9; FIG.
13 is a lens configuration diagram of an imaging optical system according to a fourth embodiment of the present invention.
FIG. 14 is a view showing a fourth aberration diagram according to the fourth embodiment shown in FIG.
FIG. 15 is a view showing the resolution according to the fourth embodiment shown in FIG.
FIG. 16 is a diagram showing lateral color values according to the fourth embodiment shown in FIG. 13; FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, embodiments of the imaging optical system according to the present invention will be described in detail with reference to the accompanying drawings, in the following description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals and redundant description thereof. Will be omitted.

1 is a lens configuration diagram of an imaging optical system according to a first embodiment of the present invention. Referring to FIG. 1, the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the infrared filter 160, and the image sensor surface 170 is shown. The drawings are exaggerated for convenience of explanation and understanding, and the shape of the spherical or aspherical surface shown in the schematic diagram of the imaging optical system is presented as an example and is not limited thereto.

As shown in FIG. 1, the imaging optical system 100 according to the present exemplary embodiment includes a first lens 110 having positive refractive power and one surface of the object side convex, and a first lens 110 having positive refractive power. On the opposite side of the second lens 120, the third lens 130 having negative refractive power and one surface on the opposite side of the second lens 120 concave, and the opposite side of the third lens 130 having positive refractive power. One surface is a meniscus shape having a convex shape, at least one surface having an aspherical surface and a negative refractive power, one surface opposite the fourth lens 140 is concave, and one surface opposite the fourth lens 140 is concave. The fifth lens 150 is composed of an aspherical surface having an inflection point. For example, the fifth lens 150 may have a shape in which the other surface of the fourth lens 140 is concave.

Here, each of the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150 may be spaced apart from each other, and may be formed on the image side from an object to be photographed. 1,2,3,4,5 lenses 110, 120, 130, 140, 150 are sequentially arranged. Here, the upper side means the image sensor surface 170. The imaging optical system 100 according to the present exemplary embodiment includes a plurality of first, second, third, fourth, and fifth lenses 110, 120, 130, 140, and 150 having different dispersion characteristics, thereby reducing chromatic aberration, thereby increasing resolution. have.

The first lens 110 and the second lens 120 have a positive refractive power to reduce the sensitivity of the imaging optical system 100, and the third lens 130 disposed next has a large dispersion and negative refractive power. The resolution can be increased by reducing chromatic aberration.

For example, the first lens 110 and the second lens 120 may be double-sided aspherical surfaces. By forming the double-sided aspherical surface, correction of various aberrations such as spherical aberration can be easily performed. Here, the first lens 110 and the second lens 120 are both formed as an aspherical surface is generated by the spherical surface of the third, fourth, fifth lens (130, 140, 150) which are provided in sequence after the second lens 120 It can reduce the design freedom and difficulty in correcting aberration.

In addition, since the fifth lens 150 is configured as an aspherical surface, the incident angle of the light source is reduced, so that there is no chromatic aberration corresponding to a small pixel, thereby increasing the resolution.

Here, the diaphragm 90 may be provided on the front surface of the first lens 110, and the infrared filter 160 and the image sensor may be provided on the opposite side of the object in the fifth lens 150.

The infrared filter 160 may include the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens so as to remove unnecessary noise among light sources flowing into the image sensor. It is provided on the path from 150 to the image sensor surface 170. For example, the infrared filter 160 may be disposed between the fifth lens 150 and the image sensor surface.

The image sensor may be a CCD, a CMOS, or the like, and the image sensor may include the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150. It detects the light source incident through it and converts it into an electrical signal.

The first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150 satisfy the following Conditional Expression 1.

[Condition 1]

1.1 <tt / f <1.5

0.4 <f12 / f <0.8

Here, tt is the distance on the optical axis from one surface of the first lens 110 to the image sensor, ｆ is the first lens 110, the second lens 120, the third lens 130, the fourth lens 140 And the combined focal length of the fifth lens 150, that is, the effective focal length of the entire optical system, and # 12 is the combined focal length of the first lens 110 and the second lens 120.

Here, by satisfying 1.1 < tt / f < 1.5, the compact imaging optical system 100 can be achieved. If the deviation from the lower limit of the conditional expression has the advantage that the size of the optical system is small, but the angle of view becomes large, the shape of the lens can not actually be produced, the overall length is too short, the optical characteristics required for the optical system It becomes difficult to be satisfied. On the other hand, if it exceeds the upper limit of 1.1 <

0.4 <f12 / f <0.8 defines the refractive power of the first and second lenses 110 and 120. If the upper limit of the conditional expression is exceeded, the power of the third, fourth, and fifth lenses 130, 140, and 150 must be increased, thereby increasing chromatic aberration. Outside the lower limit of the conditional expression, the power of the first and second lenses 110 and 120 becomes excessive, resulting in large spherical aberration and coma aberration, thereby lowering the resolution.

The first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150 satisfy the following Conditional Expression 2. Conditional Expression 2 is a condition for the correction of chromatic aberration.

[Condition Formula 2]

50> V _g1 -V _{g 3} > 25

V _g1 -V _g4 | <15

V _{g 4} -V _{g 5}

Here, V _g1 is an Abbe number of the first lens 110, V _g3 is an Abbe number of the third lens 130, V _g4 is an Abbe number of the fourth lens 140, and V _{g 5} is the Abbe's number of the fifth lens. Abbe number indicates the degree of dispersion. A large Abbe number means that the dispersion is relatively large.

When the deviation from the lower limit of 50 > V _g1 -V _{g 3} > 25 is less than the difference between the Abbe number of the first lens 110 and the Abbe number of the third lens 130, chromatic aberration increases, so that the resolution decreases. If the upper limit of 50> V _g1 -V _{g 3} > 25 is exceeded, the difference between the Abbe number of the first lens 110 and the Abbe number of the third lens 130 is large, thereby increasing the material cost.

| V _g1 -V _g4 | <15 limits the Abbe's number difference between the first lens 110 and the fourth lens 140, and | V _{g 4} -V _{g 5} | <15 is _equal to the fourth lens 140. The Abbe's number difference of the fifth lens 150 is limited to correct chromatic aberration.

The fourth lens 140 and the fifth lens 150 may satisfy the following Conditional Expressions 3 and 4.

[Condition Formula 3] | A4 |> 1.5 ＊ 10 ^-5

[Condition Formula 4] | A5 |> 1.5 ＊ 10 ^-5

Here, A4 is a linear thermal expansion coefficient of the fourth lens 140, A5 is a linear thermal expansion coefficient of the fifth lens 150. For example, the fourth lens 140 and the fifth lens 150 satisfying Conditional Expressions 3 and 4 may be formed of a plastic material, and thus are lower in price and easier to manufacture than glass materials.

Hereinafter, the present invention will be described with reference to specific numerical examples.

As described above, all of the first to fourth embodiments below have the first lens 110 having positive refractive power sequentially from the object side and having one surface convex on the object side, and the first lens having positive refractive power. 110) the second lens 120 having one side opposite to the second side, the third lens 130 having negative refractive power and one side opposite the second lens 120 concave, and the third lens 130 having positive refractive power. One surface on the opposite side is a meniscus shape having a convex shape, and at least one surface of the fourth lens 140 having an aspherical surface and a negative refractive power and one surface opposite the fourth lens 140 is concave and opposite the fourth lens 140. A fifth lens 150 is disposed, one surface of which is composed of an aspherical surface having an inflection point.

The aspherical surface used in each of the following examples is obtained from well-known Equation 1, and is used in the Conic constant (K) and the aspherical surface coefficients (A, B, C, D, E, F), and The number following is the power of ten. For example, E + 01 represents 10 ¹ and E-02 represents 10 ⁻² .

Equation 1

Where Z is the distance from the vertex of the lens in the optical axis direction, Y is the distance in the direction perpendicular to the optical axis, c is the inverse of the radius of curvature r at the vertex of the lens, and K is the Conic constant Where A, B, C, D, E, and F are aspheric coefficients.

[First Embodiment]

Table 1 below shows numerical examples according to the first embodiment of the present invention.

1 is a lens configuration diagram of an imaging optical system according to a first embodiment of the present invention, and FIGS. 2 to 4 are various aberration diagrams, resolution powers, and lateral color values of the optical systems shown in Table 1 and FIG. 1. Figure is shown.

The first embodiment is as follows. Both surfaces of the first lens 110 may be convex, the second lens 120 may be convex on one surface opposite to the first lens 110, and the third lens 130 may be the second lens 120. Only one side of the opposite side may be concave.

The condition is as follows. tt is 6.03, f is 4.80, f12 is 2.89, V _g1 is 61.25, V _g2 is 56.11, V _g3 is 25.46, V _g4 is 56.11 and V _g5 is 56.11.

Face number Radius of curvature thickness Refractive index Dispersion value (Abe number) Remarks iris infinity 0.050000 111 3.08348 0.827262 1.5891 61.25 First lens
(110) 113 -7.28426 0.100000 121 -47.12879 0.350000 1.5441 56.11 Second lens
(120) 123 -4.88793 0.100000 131 -95.95297 0.251693 1.8052 25.46 Third lens
(130) 133 4.29333 0.730535 141 -3.13268 1.269611 1.5441 56.11 Fourth lens
(140) 143 -1.16694 0.277347 151 -17.19590 0.550000 1.5441 56.11 Fifth lens
(150) 153 1.43595 0.251812 Infrared filter object side infinity 0.300000 1.5168 64.16 IR filter upper side infinity 0.991268 Image sensor infinity -0.012509

The aspherical coefficients of Example 1 according to Equation 1 are shown in Table 2 below.

Cotton number K A B C D E 111 -3.323785 -.601247E-02 0.238339E-02 -.354482E-01 0.451019E-01 -.197163E-01 113 3.437464 -.252152E-02 0.521642E-03 0.254850E-02 0.662535E-02 121 -130.360740 0.799389E-03 0.546514E-03 0.245815E-02 0.504177E-03 123 5.494412 -.173021E-01 -.232537E-02 -.193048E-01 0.103987E-01 -.337111E-02 141 0.321560 -.339144E-01 -.182358E-01 0.969096E-03 -.208343E-02 0.141854E-02 143 -3.867164 -.772375E-01 0.356545E-01 -.158440E-01 0.438958E-02 -.495290E-04 151 1.000000 -.493671E-01 0.445604E-02 0.326352E-02 -.117706E-02 0.126310E-03 153 -7.564596 -.500452E-01 0.120037E-01 -.252347E-02 0.278898E-03 -.146125E-04

Through Example 1, as shown in Figure 2, it can be seen that the longitudinal spherical aberration is small in the range of -0.025 to +0.025, astigmatic field curves are -0.05 to 0 It can be seen that the shape is close to a straight line in the range of, and the distortion appears small in the range of 0 to 1.

As shown in FIG. 3, the result of Example 1 is derived close to the diffraction limit axis, indicating that the resolution is high. In addition, as shown in Figure 4, it can be seen that the lateral color is small in the range -0.0005 to 0.001.

Second Embodiment

Table 3 below shows a numerical example of the first embodiment of the present invention.

5 is a lens configuration diagram of an imaging optical system according to a second exemplary embodiment of the present invention, and FIGS. 6 to 8 illustrate various aberration diagrams, resolution powers, and lateral color values of the optical systems shown in Tables 3 and 5. .

The second embodiment is as follows. Unlike the first embodiment, the first lens 210 may have a convex shape only on the object side, the second lens 220 may have a convex shape on both sides, and the third lens 230 may have concave surfaces on both sides. Can be.

Here, the conditions are as follows. Tt is 6.498, f is 4.972, f12 is 2.742, V _g1 is 61.25, V _g2 is 56.11, V _g3 is 25.46, V _g4 is 56.11 and V _g5 is 56.11. The other conditions are the same as the first embodiment described above, and overlapping descriptions will be omitted.

Face number Radius of curvature thickness Refractive index Dispersion value (Abe number) Remarks iris infinity 0.050000 211 3.26595 0.463547 1.5891 61.25 First lens
(210) 213 14.17174 0.100000 221 7.61258 0.607296 1.5441 56.11 Second lens
(220) 223 -2.98050 0.156809 231 -6.36549 0.681096 1.8052 25.46 Third lens
(230) 233 7.22346 0.695704 241 -4.30139 1.500000 1.5441 56.11 Fourth lens
(240) 243 -1.06281 0.100000 251 -17.19590 0.681756 1.5441 56.11 Fifth lens
(250) 253 1.12424 0.353717 Infrared filter object side infinity 0.300000 1.5168 64.16 IR filter upper side infinity 0.813238 Image sensor infinity -0.005060

The aspherical coefficients of Example 2 according to Equation 1 are shown in Table 4 below.

Face number K A B C D E 211 -3.568150 -.683170E-02 0.336452E-02 -.324443E-01 0.352454E-01 -.152832E-01 213 0.000000 -.438300E-02 0.453930E-02 -.638489E-02 0.922929E-02 221 0.000000 -.182968E-02 -.280905E-02 0.295416E-02 -.191023E-02 223 2.405328 -.459301E-02 -.181393E-02 -.128325E-01 0.999559E-02 -.505590E-02 241 -0.338846 -.314183E-01 -.203830E-01 0.284949E-02 0.121538E-02 0.234591E-04 243 -3.952809 -.805006E-01 0.337854E-01 -.151633E-01 0.428856E-02 -.306493E-03 251 61.477321 -.622481E-01 0.844732E-02 0.345067E-02 -.115116E-02 0.968217E-04 253 -6.039775 -.458060E-01 0.117729E-01 -.223500E-02 0.222979E-03 -.101209E-04

Through Example 2, as shown in Figure 6, it can be seen that the longitudinal spherical aberration is small in the range of -0.01 to +0.01, astigmatic field curves are -0.025 to 0 It can be seen that the shape is close to a straight line in the range of, and the distortion is small in the range of 0 to 2.

As shown in FIG. 7, the results of Example 1 are derived close to the diffraction limit axis, indicating that the resolution is high. 8, it can be seen that the lateral color is as small as -0.0005 to 0.001.

Third Embodiment

Table 5 below shows numerical examples of the first embodiment of the present invention.

9 is a lens configuration diagram of an imaging optical system according to a third exemplary embodiment of the present invention, and FIGS. 10 to 12 illustrate various aberration diagrams, resolution powers, and lateral color values of the optical systems shown in Tables 5 and 9. .

The third embodiment is as follows. Unlike the first embodiment, the first lens 310 may have a convex shape only on the object side, the second lens 320 may have a convex surface on both sides, and the third lens 330 may have concave surfaces on both sides. Can be.

The condition is as follows. Tt is 6.546, f is 5.018, f12 is 2.772, V _g1 is 56.11, V _g2 is 56.11, V _g3 is 25.45, V _g4 is 56.11 and V _g5 is 56.11. The other conditions are the same as the first embodiment described above, and overlapping descriptions will be omitted.

Face number Radius of curvature thickness Refractive index Dispersion value (Abe number) Remarks iris infinity 0.050000 311 3.20134 0.380037 1.5441 56.11 First lens
(310) 313 7.90431 0.103136 321 5.14838 0.628603 1.5441 56.11 Second lens
(320) 323 -3.03104 0.149019 331 -6.54708 0.774794 1.8051 25.46 Third lens
(330) 333 6.93282 0.810199 341 -5.44520 1.474736 1.5441 56.11 Fourth lens
(340) 343 -1.08771 0.100000 351 -17.19590 0.668393 1.5441 56.11 Fifth lens
(350) 353 1.09299 0.381388 Infrared filter object side infinity 0.300000 1.5168 64.17 IR filter upper side infinity 0.729764 Image sensor infinity -0.004301

The aspherical coefficients of Example 3 according to Equation 1 are shown in Table 6 below.

Face number K A B C D E 311 -3.410649 -.640148E-02 0.346871E-02 -.330292E-01 0.330097E-01 -.139718E-01 313 0.000000 -.377181E-02 0.565220E-02 -.803630E-02 0.798647E-02 321 0.000000 -.335175E-02 -.229532E-02 0.360158E-02 -.298504E-02 323 2.320642 -.413198E-02 -.138682E-02 -.119951E-01 0.984300E-02 -.500315E-02 341 -2.559742 -.286281E-01 -.195783E-01 0.206521E-02 0.120904E-02 -.181892E-03 343 -4.202667 -.791773E-01 0.328356E-01 -.151431E-01 0.427092E-02 -.339616E-03 351 62.568755 -.684558E-01 0.983409E-02 0.358128E-02 -.113667E-02 0.879084E-04 353 -5.779793 -.447201E-01 0.116015E-01 -.213965E-02 0.209093E-03 -.936824E-05

Through Example 3, as shown in FIG. 10, it can be seen that the longitudinal spherical aberration is small in the range of -0.01 to +0.01, and the astigmatic field curves are -0.025 to 0. It can be seen that the shape is close to a straight line in the range of, and the distortion appears small in the range of 0 to 1.

As shown in FIG. 11, the result of Example 1 is derived close to the diffraction limit axis, indicating that the resolution is high. 12, it can be seen that the lateral color is as small as -0.0005 to 0.0005.

[Example 4]

Table 7 below shows numerical examples according to the fourth embodiment of the present invention.

FIG. 13 is a lens configuration diagram of an imaging optical system according to a fourth exemplary embodiment of the present invention, and FIG. 14 is a diagram illustrating an aberration diagram according to the fourth exemplary embodiment illustrated in FIG. 13, and FIG. 15 is illustrated in FIG. 13. FIG. 16 is a diagram illustrating a resolution power value according to the fourth embodiment, and FIG. 16 is a diagram illustrating a lateral color value according to the fourth embodiment illustrated in FIG. 13.

13 is a lens configuration diagram of an imaging optical system according to a fourth exemplary embodiment of the present invention, and FIGS. 14 to 16 illustrate various aberration diagrams, resolution powers, and lateral color values of the optical systems shown in Tables 7 and 13. .

The fourth embodiment is as follows. The first lens 410 may have a convex shape on the object side, and the surface opposite the object may have a concave shape, the second lens 420 may have a convex shape on both sides, and the third lens 430 may have a both side convex shape. It may be concave.

The condition is as follows. Tt is 6.455, f is 5.025, f12 is 2.785, V _g1 is 56.11, V _g2 is 56.11, V _g3 is 25.60, V _g4 is 56.11 and V _g5 is 56.11. The other conditions are the same as the first embodiment described above, and overlapping descriptions will be omitted.

Face number Radius of curvature thickness Refractive index Dispersion value (Abe number) Remarks iris infinity 0.050000 . . 411 2.85359 0.287863 1.5441 56.11 First lens
(410) 413 3.85333 0.104742 . . 421 3.95972 0.777576 1.5441 56.11 Second lens
(420) 423 -2.74633 0.105822 . . 431 -4.73370 0.693974 1.6142 25.60 Third lens
(430) 433 6.84872 0.832678 . . 441 -5.76385 1.360177 1.5441 56.11 Fourth lens
(440) 443 -1.29658 0.174419 . . 451 -17.19590 0.671844 1.5441 56.11 Fifth lens
(450) 453 1.28608 0.348118 . . Infrared filter object side infinity 0.300000 1.5167 64.20 IR filter upper side infinity 0.750825 . . Image sensor infinity -0.002980 . .

The aspherical coefficients of Example 4 according to Equation 1 are shown in Table 8 below.

Face number K A B C D E 311 -3.292565 -.610550E-02 0.275714E-02 -.334193E-01 0.307117E-01 -.134821E-01 313 0.000000 -.911439E-02 0.684634E-02 -.916844E-02 0.395180E-02 321 0.000000 -.202576E-02 -.445878E-03 0.186388E-02 -.600655E-02 323 2.068969 -.201587E-02 -.266652E-02 -.113819E-01-02 0.105198E-01 -.495697E 331 1.744972 -.304258E-02 -.120632E-02 0.655500E-03 0.195409E-02 333 2.481006 0.176244E-03 0.136022E-02 0.830260E-03 0.772700E-03 341 -5.932620 -.239284E-01 -.179056E-01 0.252673E-03 0.126227E-02 0.119168E-03 343 -4.628798 -.774997E-01 0.308327E-01 -.149701E-01 0.431129E-02 -.376982E-03 351 63.744493 -.817666E-01 0.121925E-01 0.363661E-02 -.113843E-02 0.800805E-04 353 -5.952706 -.462450E-01 0.119127E-01 -.204249E-02 0.189317E-03 -.831316E-05

Through Example 4, as shown in FIG. 14, it can be seen that the longitudinal spherical aberration is small in the range of -0.01 to +0.01, and the astigmatic field curves are -0.025 to 0. It can be seen that the shape is close to a straight line in the range of, and the distortion appears small in the range of 0 to 1.

As shown in FIG. 15, the result of Example 1 is derived close to the diffraction limit axis, indicating that the resolution is high. 16, it can be seen that the lateral color is as small as -0.0005 to 0.0005.

Through the above embodiment, the aberration diagram and the resolution as shown in FIGS. 2, 3, 4, 6, 7, 7, 8, 10, 11, 12, 14, 15, and 16 are reduced. It can be confirmed that an excellent optical system can be obtained.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be understood that the invention may be varied and varied without departing from the scope of the invention.

Many embodiments other than the above-described embodiments are within the scope of the claims of the present invention.

110, 210, 310, and 410: first lens
120, 220, 320, 420: second lens
130, 230, 330, 430: third lens
140, 240, 340, and 440: fourth lens
150, 250, 350, and 450: fifth lens

Claims (6)

A first lens having positive refractive power and having one surface convex on the object side;
A second lens having positive refractive power and having one surface opposite the first lens convex;
A third lens having negative refractive power and one surface opposite the second lens being concave;
A fourth lens having positive refractive power and a meniscus shape in which one surface opposite the third lens is convex and at least one surface is aspheric; And
A fifth lens having a negative refractive power and a surface opposite the fourth lens is concave, and one surface opposite the fourth lens is composed of an aspherical surface having an inflection point,
The first lens, the second lens, the third lens, the fourth lens and the fifth lens are spaced apart from each other, and are sequentially disposed from the object side toward the image side,
And the first lens, the second lens, the third lens, the fourth lens, and the fifth lens satisfy the following conditional expressions 1 and 2.
[Condition 1]
1.1 <tt / f <1.5
0.4 <f12 / f <0.8
[Condition Formula 2]
50> V _g1 -V _{g 3} > 25
| V _g1 -V _g4 | <15
V _{g 4} -V _{g 5}
Where tt is the distance on the optical axis from one surface of the first lens to the image sensor
ｆ: Composite focal length of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens
ｆ12: Composite focal length of the first lens and the second lens
V _g1 : Abbe number of the first lens
V _{g 3} : Abbe's number of the third lens
V _g4 : Abbe number of the fourth lens
V _{g 5} : Abbe's number of the fifth lens
The method of claim 1,
And the fourth lens and the fifth lens satisfy the following conditional expressions 3 and 4.
[Condition Formula 3] | A4 |> 1.5 ＊ 10 ^-5
[Condition Formula 4] | A5 |> 1.5 ＊ 10 ^-5
Here, A4: coefficient of thermal expansion of the fourth lens
A5: coefficient of thermal expansion of the fifth lens
The method of claim 2,
The optical system of claim 1, wherein an aperture is provided on an object side of the first lens.
The method of claim 3,
And said fifth lens has a concave shape on the other side of said fourth lens side.
The method of claim 4,
And said second lens is a double-sided aspheric surface.
The method of claim 5,
And said first lens is a double-sided aspheric surface.

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