Optical system and image pickup apparatus

Abstract

The invention discloses an optical system and an image pickup apparatus. An optical system includes a plurality of 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 an object side to an image side.

Description

Technical Field

[0001] The present disclosure relates to an optical system suitable for an image pickup device or the like. Summary of the invention

[0002] According to one aspect of the present disclosure, an optical system includes a plurality of lenses, the plurality of lenses including a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side. An image pickup device having the above optical system also constitutes another aspect of the present disclosure.

[0003] Further features of various embodiments of the present disclosure will become apparent from the following description of the embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1 is a cross-sectional view of an optical system according to Example 1 (Numerical Example 1).

[0005] Figure 2 3 is a longitudinal aberration diagram of Numerical Example 1.

[0006] Figure 3 is a cross-sectional view of an optical system according to Example 2 (Numerical Example 2).

[0007] Figure 4 is a longitudinal aberration diagram of Numerical Example 2.

[0008] Figure 5 is a cross-sectional view of an optical system according to Example 3 (Numerical Example 3).

[0009] Figure 6 3 is a longitudinal aberration diagram of Numerical Example 3.

[0010] Figure 7 is a cross-sectional view of an optical system according to Example 4 (Numerical Example 4).

[0011] Figure 8 3 is a longitudinal aberration diagram of Numerical Example 4.

[0012] Fig. 9 is a cross-sectional view of an optical system according to Example 5 (Numerical Example 5).

[0013] Fig.10 3 is a longitudinal aberration diagram of Numerical Example 5.

[0014] Fig.11 is a cross-sectional view of an optical system according to Example 6 (Numerical Example 6).

[0015] Fig.12 This is a longitudinal aberration diagram of Numerical Example 6.

[0016] Fig.13The tapered shape of the edge portion of the lens is illustrated.

[0017] Fig.14 The sag amount of the lens is shown in the figure.

[0018] Fig.15 is a schematic diagram of an image pickup device using the optical system according to any one of Examples 1 to 6. DETAILED DESCRIPTION

[0019] Referring now to the drawings, a description will be given of an embodiment according to the present disclosure.Before describing specific examples 1 to 6, a description will now be given of matters common to each of the examples.

[0020] The optical system according to each example is used in various image pickup devices such as a digital still camera, a digital video camera, a security camera, and an in-vehicle (on-board) camera.

[0021] Figure 1 , Figure 3 , Figure 5 , Figure 7 , Fig. 9 and Fig.11 The configurations of the optical systems according to Examples 1 to 6 are illustrated respectively. In each figure, the left side is the object side, and the right side is the image side. The optical system according to each example includes a plurality of lenses (six or more) including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged from the object side to the image side. The aperture stop SP is disposed between the first lens and the second lens.

[0022] FL represents an optical block such as an optical filter, a low-pass filter, an infrared cut filter, etc. IP represents an image plane. An imaging surface (light receiving surface) of an image sensor as a photoelectric conversion element such as a CCD sensor or a CMOS sensor or a film plane (photoelectric surface) of a silver film is disposed on the image plane IP.

[0023] Now, a description will be given of conditions that the optical system according to each example may satisfy.

[0024] The following inequality is satisfied:

[0025] -0.59≤S23<0.00 (1)

[0026] 1.50≤f2 / f≤3.00 (2)

[0027] Wherein R2i is the radius of curvature of the surface on the image side of the second lens, R3o is the radius of curvature of the surface on the object side of the third lens, and S23=(R2i+R3o) / (R2i-R3o), f is the focal length of the optical system, and f2 is the focal length of the second lens.

[0028] Inequality (1) defines the appropriate relationship between the surface shape of the image side of the second lens and the surface shape of the object side of the third lens. S23 is also called the shape factor of the air lens between the surface of the image side of the second lens and the surface of the object side of the third lens. In the case where the radius of curvature of the surface on the image side of the second lens becomes smaller so that S23 becomes lower than the lower limit of inequality (1), the edge portion of the second lens is locally thinned by forming a tapered portion to be engaged with the tapered portion of the third lens. In the case where S23 becomes higher than the upper limit of inequality (1), the radius of curvature of the surface on the image side of the second lens becomes larger, the refractive power becomes lower, and coma aberration appears significantly and is difficult to correct. Satisfying inequality (1) can improve the molding stability of the lens disposed near the aperture stop SP (in particular, the lens having a tapered portion on its edge portion) and satisfactorily correct the coma aberration.

[0029] Inequality (2) defines an appropriate relationship between the on-axis focal length f in the optical system and the focal length f2 of the second lens. In the case where f2 / f becomes lower than the lower limit of inequality (2), the refractive power of the second lens increases. In this case, while maintaining the lens thickness of the second lens, the radius of curvature of the lens surface decreases and the edge portion becomes thinner. In the case where f2 / f becomes higher than the upper limit of inequality (2), the refractive power of the second lens decreases. As a result, large spherical aberration occurs and is difficult to correct.

[0030] The above configuration satisfying the above conditions can realize an optical system having a reduced size, a wide viewing angle, and high optical performance while ensuring lens molding stability.

[0031] The optical system according to each example may satisfy at least one of the following inequalities (3) to (8).

[0032] Fig.13 The cone angle θ of the lens is illustrated. In each example, the cone portions TS formed on the edge portions E of at least two adjacent lenses are brought into contact (engaged) with each other to avoid relative decentering of these lenses. The edge portion E is an end portion of the lens outside the optical effective diameter to be described later. The cone angle θ of the cone portion TS is an angle between the cone portion TS and a plane perpendicular to the central axis (optical axis AXL) of the lens.

[0033] Fig.14The sag amount Sag of the lens is shown. The sag amount Sag is the length in the optical axis direction from the vertex of the lens surface (such as a point on the optical axis AXL) to the point (position) of the optical effective diameter Ea. The optical effective diameter is the radius of the area of ​​the lens surface through which light that contributes to imaging passes.

[0034] As described above, in the case where the tapered portions provided on the edge portions of adjacent lenses are in contact with each other, the following inequality (3) may be satisfied:

[0035] 0.00<cosθ≤0.77 (3)

[0036] where θ is the cone angle of the tapered portion relative to a plane perpendicular to the optical axis.

[0037] Inequality (3) defines an appropriate range of the taper angle θ. In the case where θ becomes lower than the lower limit of inequality (3), the taper angle θ becomes 90° or greater. As a result, a wedge-shaped portion shape is required at the edge portion, and the lens molding stability is reduced. In the case where θ becomes higher than the upper limit of inequality (3), the engagement length at the taper portion is reduced, and the lens is likely to be tilted relative to a plane perpendicular to the optical axis.

[0038] The following inequality (4) can be satisfied:

[0039] 1.66≤dE23 / d23≤4.56 (4)

[0040] Wherein d23 is the distance on the optical axis between the second lens and the third lens, and dE23 is the distance in the optical axis direction at the position of the optical effective diameter of each of the second lens and the third lens.

[0041] Inequality (4) defines an appropriate relationship between the distance d23 on the optical axis between the second lens and the third lens and the distance dE23 at the position of the optical effective diameter. In the case where dE23 / d23 becomes lower than the lower limit of inequality (4), the curvature of the second lens or the third lens decreases, the refractive power decreases, and correction of spherical aberration becomes difficult. In the case where dE23 / d23 becomes higher than the upper limit of inequality (4), the optical effective diameter becomes larger relative to the distance on the optical axis between the second lens and the third lens. As a result, the thickness of the edge portion becomes larger relative to the lens thickness within the optical effective diameter, and the lens thickness becomes thinner, and the lens molding stability decreases.

[0042] The following inequality (5) can be satisfied:

[0043] 0.40≤dE34 / d34≤2.00 (5)

[0044] Wherein d34 is the distance on the optical axis between the third lens and the fourth lens, and dE34 is the distance in the optical axis direction at the position of the optical effective diameter of each of the third lens and the fourth lens.

[0045] Inequality (5) defines an appropriate relationship between the distance d34 on the optical axis between the third lens and the fourth lens and the distance dE34 at the position of the optical effective diameter. In the case where dE34 / d34 becomes lower than the lower limit of inequality (5), the curvature of the third lens or the fourth lens decreases, the refractive power decreases, and it becomes difficult to correct distortion. In the case where dE34 / d34 becomes higher than the upper limit of inequality (5), the optical effective diameter becomes larger relative to the distance on the optical axis between the third lens and the fourth lens. As a result, the thickness of the edge portion becomes larger relative to the lens thickness within the optical effective diameter, the lens thickness becomes thinner, and the lens molding stability decreases.

[0046] The following inequality (6) can be satisfied:

[0047] 1.31≤TTL / ImgH≤2.20 (6)

[0048] Where ImgH is the maximum image height of the optical system, and TTL is the total length on the optical axis from the surface of the optical system closest to the object side to the image plane.

[0049] Inequality (6) defines an appropriate relationship between the maximum image height ImgH and the total optical length TTL of the optical system. In the case where TTL / ImgH becomes lower than the lower limit of inequality (6), the total optical length becomes small relative to the maximum image height, and it becomes difficult to correct aberrations. In the case where TTL / ImgH becomes higher than the upper limit of inequality (6), the total optical length becomes too large relative to the maximum image height, and it becomes difficult to miniaturize the optical system.

[0050] The following inequality (7) can be satisfied:

[0051] 35.0≤vP_2≤65.0 (7)

[0052] Here, vP_2 is the Abbe number based on the d-line of the positive lens Gp disposed closest to the object among the lenses disposed on the image side of the aperture stop SP among the plurality of lenses in the optical system.

[0053] Inequality (7) defines an appropriate range of the Abbe number vP_2 of the positive lens Gp. In order to effectively correct longitudinal chromatic aberration, the positive lens Gp may be formed using a low dispersion material whose vP_2 satisfies inequality (7).

[0054] The following inequality (8) can be satisfied:

[0055] -0.20≤Sag2 / Ea2<0.00 (8)

[0056] Wherein Ea2 is the optically effective diameter of the second lens, and Sag2 is the sag amount of the surface on the image side of the second lens.

[0057] Inequality (8) defines an appropriate relationship between the sag amount Sag2 of the second lens and the optical effective diameter Ea2. In the case where Sag2 / Ea2 becomes lower than the lower limit of inequality (8), the refractive power of the second lens decreases, and it becomes difficult to correct spherical aberration. In the case where Sag2 / Ea2 becomes higher than the upper limit of inequality (8), the surface of the image side of the second lens becomes concave, and it becomes difficult to correct spherical aberration and coma aberration.

[0058] Inequalities (1) to (8) can be replaced by the following inequalities (1a) to (8a):

[0059] -0.56≤S23≤-0.10 (1a)

[0060] 1.55≤f2 / f≤2.80 (2a)

[0061] 0.00<cosθ≤0.64 (3a)

[0062] 2.00≤dE23 / d23≤4.40 (4a)

[0063] 0.42≤dE34 / d34≤1.95 (5a)

[0064] 1.60≤TTL / ImgH≤2.15 (6a)

[0065] 40.0≤vP_2≤60.0 (7a)

[0066] -0.18≤Sag2 / Ea2≤-0.05 (8a)

[0067] Inequalities (1) to (8) can be replaced by the following inequalities (1b) to (8b):

[0068] -0.53≤S23≤-0.15 (1b)

[0069] 1.60≤f2 / f≤2.40 (2b)

[0070] 0.20≤cosθ≤0.50 (3b)

[0071] 2.30≤dE23 / d23≤4.30 (4b)

[0072] 0.44≤dE34 / d34≤1.90 (5b)

[0073] 1.80≤TTL / ImgH≤2.10 (6b)

[0074] 50.0≤vP_2≤58.0 (7b)

[0075] -0.16≤Sag2 / Ea2≤-0.06 (8b)

[0076] Satisfying at least one of inequalities (3) to (8) in addition to inequalities (1) and (2) can more easily realize an optical system having a reduced size, a wide viewing angle, and high optical performance while ensuring lens molding stability.

[0077] To further facilitate the implementation of the optical system, multiple lenses of the optical system may include an aspherical lens, which has no refractive power on the axis (at the central part) (the curvature on the optical axis is infinite) and has refractive power off the axis (at the peripheral part).

[0078] The optical system according to each example may also include an aspheric surface having an inflection point. The inflection point is a point at which the sign of the refractive power of the lens changes. For example, at least one of the multiple lenses may be a resin lens, and at least one of the surface on the object side of the resin lens and the surface on the image side of the resin lens may be an aspheric surface. In particular, the surface on the object side of the last lens disposed closest to the image plane among the multiple lenses may be formed so that its central portion is convex toward the object side and its peripheral portion is concave toward the object side, and the surface on the image side of the last lens may be formed so that its central portion is concave toward the image side and its peripheral portion is convex toward the image side.

[0079] Now, a detailed description will be given of the optical systems according to Example 1 to Example 6.

[0080] Example 1 to Example 5

[0081] Figure 1 , Figure 3 , Figure 5 , Figure 7 , Fig. 9 Each of the optical systems according to Examples 1 to 5 illustrated in the figure is composed of a first lens, an aperture stop SP, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side to the image side. The second lens corresponds to the positive lens Gp. The fifth lens and the sixth lens are resin lenses that are aspherical lenses having aspherical surfaces with inflection points on the object side and the image side. The surface on the object side of the sixth lens as the last lens has a convex shape toward the object side at its central portion and a concave shape toward the object side at its peripheral portion, and the surface on the image side of the sixth lens has a concave shape toward the image side at its central portion and a convex shape toward the image side at its peripheral portion.

[0082] Example 6

[0083] Fig.11 The optical system according to Example 6 illustrated in FIG. 1 is composed of a first lens, an aperture stop SP, 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 to the image side. The second lens corresponds to the positive lens Gp. The first lens is an aspheric lens having an aspheric surface with an inflection point on the object side, and the seventh lens is an aspheric lens having an aspheric surface with inflection points on the object side and the image side. The surface on the object side of the seventh lens as the last lens has a convex shape toward the object side at its central portion and a concave shape toward the object side at its peripheral portion, and the surface on the image side of the seventh lens has a concave shape toward the image side at its central portion and a convex shape toward the image side at its peripheral portion.

[0084] Numerical Examples 1 to 6 corresponding to Examples 1 to 6 will be shown. In each numerical example, surface number i represents the order of the surface counted from the object side. r represents the radius of curvature (mm) of the i-th surface from the object side, d represents the lens thickness or air gap (mm) between the i-th surface and the (i+1)-th surface, and nd represents the refractive index of the optical material between the i-th surface and the (i+1)-th surface for the d-line. vd is the Abbe number based on the d-line of the optical material between the i-th surface and the (i+1)-th surface. The Abbe number vd based on the d-line is represented as follows:

[0085] vd=(Nd-1) / (NF-NC)

[0086] Here, Nd, NF, and NC are refractive indices for d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) among Fraunhofer lines.

[0087] X=(h2 / R) / [1+√{1-(1+k)(h / R)2}]1 / 2+A4×h4+A6×h6+A8×h8+A10×h10+A12×h12

[0088] In each numerical example, d, focal length [mm], F number and half angle of view (°) are all values ​​of the focused state of the optical system on the object at infinity. BF is the back focal length (mm). The back focal length is the distance on the optical axis from the lens surface closest to the image plane (the last surface) of the optical system to the paraxial image plane expressed as an air equivalent length. The total lens length is the distance on the optical axis from the lens surface closest to the object (the frontmost surface) of the optical system to the last surface plus the back focal length, and corresponds to the total length TTL in inequality (6).

[0089] The asterisk "*" next to the surface number means that the surface has an aspherical shape. The aspherical shape is represented by the following expression:

[0090] X=(h 2 / R) / [1+√{1-(1+k)(h / R) 2}] 1 / 2 +A4×h 4 +A6×h 6 +A8×h S +A10×h 10 +A12×h 12

[0091] Where X is the displacement relative to the surface vertex in the direction of the optical axis, h is the height from the optical axis in the direction perpendicular to the optical axis, the light travel direction is set to be positive, R is the paraxial curvature radius, K is the cone constant, and A4, A6, A8, A10 to A12 are aspheric coefficients. "e±XX" in the cone constant and aspheric coefficient means "×10 ±XX ”.

[0092] Table 1 summarizes the values ​​of inequalities (1) to (8) for each numerical example.

[0093] Figure 2 , Figure 4 , Figure 6 , Figure 8 , Fig.10 and Fig.12 The longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the optical systems according to Numerical Examples 1 to Numerical Examples 6 in the focused state on an object at infinity are illustrated respectively. In the spherical aberration diagram, Fno indicates the F number, the solid line indicates the spherical aberration amount for the d line (wavelength 587.6 nm), and the alternating long and two short dashed lines indicate the spherical aberration amount for the g line (wavelength 435.8 nm). The horizontal axis is the defocus amount ranging from -0.100 to +0.100 [mm]. In the astigmatism diagram, the solid line S indicates the astigmatism amount (field curvature amount) on the sagittal image plane, and the dashed line M indicates the astigmatism amount on the meridional image plane. The horizontal axis is the same as the spherical aberration.

[0094] The distortion diagram illustrates the amount of distortion for the d-line. The horizontal axis ranges from -20.000% to +20.000%. The chromatic aberration diagram illustrates the amount of lateral chromatic aberration for the g-line. The horizontal axis ranges from -0.020mm to +0.020mm. ω is the half viewing angle (°).

[0095] Numerical Example 1

[0096] Unit: mm

[0097] Surface data

[0098]

[0099]

[0100] Aspheric surface data

[0101] Surface 1

[0102] K=9.90002e+01 A4=2.69929e-01 A6=-2.62395e-01 A8=3.26642e-01

[0103] A10=-2.83439e-01 A12=1.57972e-01 A14=-4.41437e-02 A16=3.03934e-03

[0104] Surface 2

[0105] K=3.57596e+00 A4=4.04469e-01 A6=-2.95327e-01 A8=5.10817e-01

[0106] A10=1.58440e+00 A12=-7.91944e+00 A14=1.54251e+01 A16=-1.08170e+01

[0107] Surface 4

[0108] K=0.00000e+00 A4=-4.42968e-02 A6=1.95834e-02 A8=-1.55123e-01

[0109] A10=-5.40909e-02

[0110] Surface 5

[0111] K=0.00000e+00 A4=-1.70883e-01 A6=7.37522e-02 A8=-9.92577e-02

[0112] A10=1.34773e-01 A12=-1.51087e-01

[0113] Surface 7

[0114] K=0.00000e+00 A4=-1.20111e-01 A6=8.85577e-02 A8=-3.04424e-02

[0115] A10=2.91164e-02 A12=-1.16655e-02

[0116] Surface 8

[0117] K=0.00000e+00 A4=6.45329e-02 A6=-2.48897e-01 A8=1.47799e-01

[0118] A10=-1.45545e-02

[0119] Surface 9

[0120] K=0.00000e+00 A4=3.26282e-01 A6=-2.86700e-01 A8=1.66888e-01

[0121] A10=-4.42501e-02 A12=3.79471e-03

[0122] Surface 10

[0123] K=0.00000e+00 A4=1.20327e-01 A6=-2.60615e-02 A8=-3.35844e-03

[0124] A10=2.18625e-03 A12=-3.03343e-04

[0125] Surface 11

[0126] K=0.00000e+00 A4=5.11198e-02 A6=-3.95871e-02 A8=9.72543e-03

[0127] A10=-1.66003e-03

[0128] Surface 12

[0129] K=0.00000e+00 A4=1.80852e-01 A6=-5.21144e-02 A8=7.15455e-03

[0130] A10=-4.47579e-04

[0131] Surface 13

[0132] K=-9.27669e-01 A4=-1.83614e-01 A6=3.26856e-02 A8=-4.27438e-03

[0133] A10=3.17448e-04

[0134] Surface 14

[0135] K=-2.72910e+00 A4=-9.91445e-02 A6=3.21312e-02 A8=-7.34233e-03

[0136] A10=1.04723e-03 A12=-8.68265e-05 A14=3.16248e-06

[0137] Various data

[0138]

[0139] Numerical Example 2

[0140] Unit: mm

[0141] Surface data

[0142]

[0143]

[0144] Aspheric surface data

[0145] Surface 1

[0146] K=9.67841e+01 A4=3.34490e-01 A6=-3.10866e-01 A8=3.59136e-01

[0147] A10=-3.18637e-01 A12=1.93437e-01 A14=-6.23518e-02 A16=5.52754e-03

[0148] Surface 2

[0149] K=3.63450e+00 A4=4.35880e-01 A6=3.43973e-01 A8=-1.19595e+00

[0150] A10=1.36672e+00 A12=-2.92109e+00 A14=1.80170e+01 A16=-2.08068e+01

[0151] Surface 4

[0152] K=0.00000e+00 A4=2.02238e-02 A6=-8.72034e-02 A8=2.34233e-01

[0153] A10=-1.41787e-01

[0154] Surface 5

[0155] K=0.00000e+00 A4=-2.40854e-01 A6=1.48514e-01 A8=-1.08695e-02

[0156] A10=-1.78754e-01 A12=1.46635e-01

[0157] Surface 7

[0158] K=0.00000e+00 A4=-1.96604e-01 A6=1.24591e-01 A8=-1.35871e-02

[0159] A10=1.81806e-02 A12=-8.74667e-03

[0160] Surface 8

[0161] K=0.00000e+00 A4=2.94802e-02 A6=-2.14856e-01A8=1.31962e-01

[0162] A10=2.03303e-03

[0163] Surface 9

[0164] K=0.00000e+00 A4=2.86654e-01 A6=-2.09965e-01A8=1.07292e-01

[0165] A10==-2.07780e-02 A12=-8.14649e-04

[0166] Surface 10

[0167] K=0.00000e+00 A4=9.79067e-02 A6=1.30777e-03 A8=-2.06164e-02

[0168] A10=7.25192e-03 A12=-1.02729e-03

[0169] Surface 11

[0170] K=0.00000e+00 A4=2.95807e-02 A6=-3.94769e-02A8=8.36568e-03

[0171] A10=-1.32300e-03

[0172] Surface 12

[0173] K=0.00000e+00 A4=1.83636e-01 A6=-5.50412e-02 A8=7.34860e-03

[0174] A10=-4.13531e-04

[0175] Surface 13

[0176] K=-8.86595e-01 A4=-1.90092e-01 A6=3.55751e-02 A8=-5.23180e-03

[0177] A10=4.05644e-04

[0178] Surface 14

[0179] K=-2.92138e+00 A4=-1.02409e-01 A6=3.44602e-02 A8=-8.15530e-03

[0180] A10=1.20272e-03 A12=-1.03365e-04 A14=3.95304e-06

[0181] Various data

[0182]

[0183] Numerical Example 3

[0184] Unit: mm

[0185] Surface data

[0186]

[0187]

[0188] Aspheric surface data

[0189] Surface 1

[0190] K=9.89999e+01 A4=2.96570e-01 A6=-2.74326e-01A8=3.33396e-01

[0191] A10=-2.85924e-01 A12=1.58728e-01 A14=-4.06374e-02A16=1.03894e-03

[0192] Surface 2

[0193] K=4.51982e+00 A4=4.32042e-01 A6=-2.20712e-01A8=4.27436e-01

[0194] A10=1.31593e+00 A12=-7.15287e+00 A14=1.65575e+01 A16=-1.29020e+01

[0195] Surface 4

[0196] K=0.00000e+00 A4=-4.43698e-02 A6=-1.36464e-02 A8=-5.31461e-02

[0197] A10=-2.55892e-01

[0198] Surface 5

[0199] K=0.00000e+00 A4=-2.14168e-01 A6=9.47346e-02 A8=-9.82462e-02

[0200] A10=1.34655e-01 A12=-1.97190e-01

[0201] Surface 7

[0202] K=0.00000e+00 A4=-1.40585e-01 A6=1.11879e-01 A8=-1.44115e-02

[0203] A10=2.91427e-02 A12=-1.83949e-02

[0204] Surface 8

[0205] K=0.00000e+00 A4=5.58113e-02 A6=-2.51752e-01 A8=1.55751e-01

[0206] A10=3.81027e-05

[0207] Surface 9

[0208] K=0.00000e+00 A4=3.08237e-01 A6=-2.87325e-01A8=1.67972e-01

[0209] A10=-4.05462e-02 A12=-9.04188e-04

[0210] Surface 10

[0211] K=0.00000e+00 A4=1.20140e-01 A6=-2.79746e-02 A8=-3.54032e-03

[0212] A10=2.08016e-03 A12=-3.56861e-04

[0213] Surface 11

[0214] K≤0.00000e+00 A4=5.21962e-02 A6=-4.07358e-02A8=1.02293e-02

[0215] A10=-1.78847e-03

[0216] Surface 12

[0217] K=0.00000e+00 A4=1.83311e-01 A6=-5.30339e-02 A8=7.26012e-03

[0218] A10=-4.55350e-04

[0219] Surface 13

[0220] K=-8.93058e-01 A4=-1.81266e-01 A6=3.26088e-02 A8=-4.15078e-03

[0221] A10=2.76107e-04

[0222] Surface 14

[0223] K=-2.74514e+00 A4=-9.92078e-02 A6=3.22442e-02 A8=-7.37018e-03

[0224] A10=1.04751e-03 A12=-8.66091e-05 A14=3.15905e-06

[0225] Various data

[0226]

[0227] Numerical Example 4

[0228] Unit: mm

[0229] Surface data

[0230]

[0231]

[0232] Aspheric surface data

[0233] Surface 1

[0234] K=9.90091e+01 A4=2.74957e-01 A6=-2.13253e-01 A8=2.07576e-01

[0235] A10=-1.03873e-01 A12=1.36720e-03 A14=3.48376e-02 A16=-1.32523e-02

[0236] Surface 2

[0237] K=9.88411e+00 A4=4.21547e-01 A6=-2.23705e-01 A8=-4.50773e-01

[0238] A10=4.44887e+00 A12=-1.24000e+01 A14=1.87107e+01 A16=-1.13162e+01

[0239] Surface 4

[0240] K=0.00000e+00 A4=-4.77872e-02 A6=-2.69298e-01A8=9.53964e-01

[0241] A10=-1.77358e+00

[0242] Surface 5

[0243] K=0.00000e+00 A4=-3.41695e-01 A6=2.51110e-01 A8=-2.35164e-01

[0244] A10=2.89013e-01 A12=-3.02640e-01

[0245] Surface 7

[0246] K=0.00000e+00 A4=-2.81367e-01 A6=1.55669e-01 A8=-4.50000e-02

[0247] A10=1.27961e-01 A12=-6.29497e-02

[0248] Surface 8

[0249] K=0.00000e+00 A4=-1.78289e-02 A6=-1.83697e-01 A8=2.24181e-02

[0250] A10=7.72461e-02

[0251] Surface 9

[0252] K=0.00000e+00 A4=3.46661e-01 A6=-2.18654e-01 A8=1.40550e-03

[0253] A10=9.53493e-02 A12=-2.71074e-02

[0254] Surface 10

[0255] K = 0.00000e+00 A4 = 1.65416e-01 A6 = -3.93858e-02 A8 = -2.04161e-02

[0256] A10=1.62875e-02 A12=-3.15256e-03

[0257] Surface 11

[0258] K=0.00000e+00 A4=5.82279e-02 A6=-4.12553e-02 A8=1.07833e-02

[0259] A10=-1.84058e-03

[0260] Surface 12

[0261] K=0.00000e+00 A4=1.92018e-01 A6=-5.31327e-02 A8=7.13338e-03

[0262] A10=-3.84994e-04

[0263] Surface 13

[0264] K=-7.99601e-01 A4=-1.68649e-01 A6=3.35701e-02 A8=-4.98014e-03

[0265] A10=3.13064e-04

[0266] Surface 14

[0267] K=-2.86337e+00 A4=-9.36456e-02 A6=3.11706e-02 A8=-7.33434e-03

[0268] A10=1.07299e-03 A12=-9.16239e-05 A14=3.41945e-06

[0269] Various data

[0270] Numerical Example 5

[0271] Unit: mm

[0272] Surface data

[0273]

[0274] Aspheric surface data

[0275] Surface 1

[0276] K=-9.90000e+01 A4=2.44842e-01 A6=-2.49793e-01 A8=3.07521e-01

[0277] A10=-2.70426e-01 A12=1.45740e-01 A14=-4.17283e-02 A16=4.62671e-03

[0278] Surface 2

[0279] K=2.58517e+00 A4=3.77741e-01 A6=-3.27268e-01 A8=6.17591e-01

[0280] A10=9.02188e-01 A12=-5.88191e+00 A14=9.63382e+00 A16=-5.23792e+00

[0281] Surface 4

[0282] K=0.00000e+00 A4=-2.95271e-02 A6=-4.40647e-02 A8=-4.39331e-02

[0283] A10=2.39323e-02

[0284] Surface 5

[0285] K=0.00000e+00 A4=-1.72101e-01 A6=1.11261e-01 A8=-5.04755e-02

[0286] A10=-1.24475e-01 A12=1.26349e-01

[0287] Surface 7

[0288] K=0.00000e+00 A4=-1.32679e-01 A6=1.07538e-01 A8=-6.98770e-02

[0289] A10=2.44056e-02 A12=-3.03499e-03

[0290] Surface 8

[0291] K=0.00000e+00 A4=7.10477e-02 A6=-2.47000e-01 A8=1.41996e-01

[0292] A10=-3.23519e-02

[0293] Surface 9

[0294] K=0.00000e+00 A4=3.08539e-01 A6=-2.73380e-01 A8=1.58813e-01

[0295] A10=-4.59732e-02 A12=4.58404e-03

[0296] Surface 10

[0297] K=0.00000e+00 A4=9.49834e-02 A6=-2.36609e-02 A8=-6.77300e-04

[0298] A10=2.35794e-03 A12=-5.37719e-04

[0299] Surface 11

[0300] K=0.00000e+00 A4=6.23075e-02 A6=-4.25202e-02 A8=1.03858e-02

[0301] A10=-1.91516e-03

[0302] Surface 12

[0303] K=0.00000e+00 A4=1.87618e-01 A6=-5.52500e-02 A8=7.35950e-03

[0304] A10=-4.29992e-04

[0305] Surface 13

[0306] K=-9.08692e-01 A4=-1.78329e-01 A6=3.14907e-02 A8=-4.44126e-03

[0307] A10=3.22297e-04

[0308] Surface 14

[0309] K=-2.87538e+00 A4=-9.73192e-02 A6=3.19685e-02 A8=-7.30878e-03

[0310] A10=1.04469e-03 A12=-8.75248e-05 A14=3.21185e-06

[0311] Various data

[0312]

[0313]

[0314] Numerical Example 6

[0315] Unit: mm

[0316] Surface data

[0317]

[0318] Aspheric surface data

[0319] Surface 1

[0320] K=-2.85341e+01 A4=3.03177e-01 A6=-3.20876e-01 A8=2.97182e-01

[0321] A10=-1.96677e-01 A12=8.52122e-02 A14=-2.12615e-02 A16=2.22315e-03

[0322] Surface 2

[0323] K=-1.68364e+02 A4=6.83211e-01 A6=-6.35808e-01 A8=5.15567e-01

[0324] A10=6.79769e-01 A12=-2.63820e+00 A14=3.72581e+00 A16=-1.96605e+00

[0325] Surface 4

[0326] K=0.00000e+00 A4=1.82483e-02 A6=-2.87274e-01 A8=7.53900e-01

[0327] A10=-7.66303e-01

[0328] Surface 5

[0329] K=0.00000e+00 A4=4.98478e-02 A6=-4.48516e-01 A8=7.17536e-01

[0330] A10=-2.20127e-01 A12=-8.46379e-02

[0331] Surface 7

[0332] K=0.00000e+00 A4=6.48390e-02 A6=-3.19105e-01 A8=3.42700e-01

[0333] A10=2.71052e-02 A12=-8.43733e-02

[0334] Surface 8

[0335] K=0.00000e+00 A4=1.12560e-01 A6=-2.11901e-01 A8=-5.04672e-02

[0336] A10=1.29264e-01

[0337] Surface 9

[0338] K=0.00000e+00 A4=3.88130e-01 A6=-2.80342e-01 A8=4.60709e-02

[0339] A10=1.02443e-01 A12=-2.54533e-02

[0340] Surface 10

[0341] K=0.00000e+00 A4=2.16787e-01 A6=-6.12781e-02 A8=2.03115e-03

[0342] A10=4.08690e-03 A12=-9.45404e-04

[0343] Surface 11

[0344] K=0.00000e+00 A4=6.44323e-02 A6=-6.02014e-02 A8=5.28765e-03

[0345] A10=5.71006e-05

[0346] Surface 12

[0347] K=0.00000e+00 A4=2.23087e-02 A6=-7.59855e-03 A8=-3.71058e-03

[0348] A10=3.10301e-03

[0349] Surface 13

[0350] K=-6.46661e+23 A4=-1.23483e-01 A6=4.31916e-02 A8==-7.76464e-03

[0351] A10=-4.30659e-04 A12=2.62888e-04

[0352] Surface 14

[0353] K=-5.10184e+01 A4=-2.22487e-02 A6=2.01134e-02 A8=-8.72629e-03

[0354] A10=1.51142e-03 A12=-1.09551e-04

[0355] Surface 15

[0356] K=1.04774e+00 A4=-1.09534e-01 A6=2.12363e-02 A8=-2.82349e-03

[0357] A10=1.76150e-04 A12=-5.94746e-06

[0358] Surface 16

[0359] K=-4.30910e+00 A4=-8.63616e-02 A6=3.03324e-02 A8=-7.21624e-03

[0360] A10=1.01020e-03 A12=-7.75406e-05 A14=2.52645e-06

[0361] Various data

[0362]

[0363] Table 1

[0364]

[0365] Image pickup device

[0366] Fig.15 A digital still camera (image pickup device) using an optical system according to any one of Examples 1 to 6 as an imaging optical system is illustrated. In the camera 10, reference numeral 13 denotes a camera body, and reference numeral 11 denotes an imaging optical system including one of the optical systems according to Examples 1 to 6. Reference numeral 12 denotes an image sensor such as a CCD sensor or a CMOS sensor that is built into the camera body 13 and receives an object image formed by the imaging optical system 11 (images the object).

[0367] By using an imaging optical system including one of the optical systems according to Examples 1 to 6, a compact camera that can capture images with a wide viewing angle and good quality can be realized.

[0368] The optical system according to each example is not limited to Fig.15The camera 10 illustrated in the figure is applicable to various image pickup devices such as digital video cameras and film-based cameras. The camera may be an integrated lens type or a lens interchangeable type, and may be a single-lens reflex camera or a mirrorless camera.

[0369] Although the present disclosure has described example embodiments, it is to be understood that some embodiments are not limited to the disclosed embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0370] Each example can provide an optical system that can ensure lens formation stability and has a reduced size and a wide viewing angle.

Claims

1. An optical system, comprising: A plurality of lenses include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence from an object side to an image side. 2 . The optical system of claim 1 , further comprising an aperture stop disposed between the first lens and the second lens.

3. The optical system according to claim 1, characterized in that The following inequality is satisfied: -0.59≤S23<0.00 1.50≤f2 / f≤3.00 Wherein R2i is the radius of curvature of the surface on the image side of the second lens, R3o is the radius of curvature of the surface on the object side of the third lens, S23=(R2i+R3o) / (R2i-R3o), f is the focal length of the optical system, and f2 is the focal length of the second lens.

4. The optical system according to claim 1, characterized in that In a case where tapered portions provided on edge portions of adjacent lenses among the plurality of lenses are in contact with each other, the following inequality is satisfied: 0.00 <cosθ≤0.77 where θ is the cone angle between each tapered portion and a plane perpendicular to the optical axis.

5. The optical system according to claim 1, characterized in that The following inequality is satisfied: 1.66≤dE23 / d23≤4.56 Wherein d23 is the distance on the optical axis between the second lens and the third lens, and dE23 is the distance on the optical axis direction between the second lens and the third lens at the position of the optical effective diameter.

6. The optical system according to claim 1, characterized in that The following inequality is satisfied: 0.40≤dE34 / d34≤2.00 Wherein d34 is the distance on the optical axis between the third lens and the fourth lens, and dE34 is the distance in the optical axis direction at the position of the optical effective diameter of each of the third lens and the fourth lens.

7. The optical system according to claim 1, characterized in that The following inequality is satisfied: 1.31≤TTL / ImgH ≤ 2.20 Where ImgH is the maximum image height of the optical system, and TTL is the total length on the optical axis from the surface of the optical system closest to the object to the image plane.

8. The optical system according to claim 1, characterized in that The following inequality is satisfied: 35.0≤vP_2≤65.0 Wherein vP_2 is the Abbe number based on the d-line of the positive lens closest to the object among the lenses disposed on the image side of the aperture stop in the plurality of lenses.

9. The optical system according to claim 6, characterized in that The second lens is the positive lens.

10. The optical system according to claim 1, characterized in that The following inequality is satisfied: -0.20≤Sag2 / Ea2<0.00 Wherein Ea2 is the effective optical diameter of the second lens, and Sag2 is the sag amount of the surface on the image side of the second lens.

11. The optical system according to claim 1, characterized in that At least one of the plurality of lenses is a resin lens, and at least one of a surface on an object side of the resin lens and a surface on an image side of the resin lens has an aspherical shape.

12. The optical system according to claim 1, characterized in that The surface on the object side of the last lens disposed closest to the image plane among the plurality of lenses has a central portion convex toward the object side and a peripheral portion concave toward the object side, The image-side surface of the last lens has a central portion that is concave toward the image side and a peripheral portion that is convex toward the image side.

13. The optical system according to claim 1, characterized in that The optical system consists of the first lens, the aperture stop, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens as the last lens in order from the object side to the image side.

14. The optical system according to any one of claims 1 to 13, characterized in that The optical system consists of the first lens, the aperture stop, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens as the last lens in order from the object side to the image side.

15. An image pickup device, comprising: An optical system according to any one of claims 1 to 14; and An image sensor is configured to image an object through the optical system.

Images