JP2007072291A - Zoom lens and imaging apparatus having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens achieving the compaction of an entire lens system further by adequately setting the constitution of the lens and the arrangement of a lens group. <P>SOLUTION: The zoom lens has: a first lens group B1 including a reflection member P deflecting an optical path; a second lens group B2; a third lens group B3 having positive refractive power; and a fourth lens group B4 having negative refractive power, and satisfies a condition 0.8<¾fe/fw¾<2.5 when the focal distance of the fourth lens group B4 arranged closest to an image side is defined as (fe) and the focal distance of the entire system at a wide angle end is defined as (fw). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a zoom lens, and more particularly to a zoom lens suitable as a photographing lens for a compact digital still camera.

  In recent years, a photographic lens for a digital camera and a photographic lens for a video camera have been required to be compact and have high optical performance corresponding to a solid-state imaging device having a high pixel. In particular, in a digital camera, it is desired to have a thin form that places importance on the portability of a photographer. An obstacle to thinning the camera body is the thickness from the most object-side surface of the lens unit to the imaging surface.

  One of the mainstream of conventional thinning technology is the adoption of a retractable lens barrel. The retractable lens barrel has a structure in which an optical system (lens portion) is extended from the camera body at the time of shooting and is housed in the camera body at times other than shooting. Patent Document 1 is known as an example of an optical system using the retractable lens barrel.

  In recent years, optical systems in which an optical path of an optical system is bent by a reflecting member such as a mirror or a prism to achieve a thin shape have appeared (for example, Patent Documents 2 to 4).

  Moreover, generally the photoelectric conversion part of a solid-state image sensor exists in the position (inside a hall | hole) which became deep with respect to opening. Therefore, if the incident light beam deviates more than the vertical angle, the light beam will be vignetted at this opening, leading to a decrease in sensitivity. For this reason, a conventional photographing optical system for a fixed imaging device is generally a telecentric optical system in which the angle of light incident on the imaging device is close to the vertical even in the periphery of the screen.

On the other hand, a solid-state imaging device has been proposed in which the hole structure is devised so that the light beam can be efficiently taken up to the photoelectric conversion surface even when the light beam is obliquely incident or the incident angle fluctuates. .
Japanese Unexamined Patent Publication No. 2000-9997 JP 2004-37967 A JP 2004-69808 A JP 2005-84283 A JP 11-68074 A JP 2003-224249 A

  Many zoom lenses used in small digital camera photography systems have a negative component (a lens unit having a negative refractive power) closest to the object side, and a first positive component (a lens having a positive refractive power) on the image side. Group), and a retrofocus optical system having a second positive component (a lens group having a positive refractive power) on the side closest to the image plane.

  During zooming, zooming is performed by moving the first positive component, and image plane variation due to zooming is corrected using a negative component. Then, the second positive component performs a refracting action that makes the light incident on the image plane closer to telecentricity.

  In such a retrofocus type optical system, it is effective to give a strong positive refractive power to the first positive component in order to perform a constant zooming action with a small amount of movement.

  However, in order to obtain a telecentric optical system, it is necessary to share the positive refractive power in the second positive component and to arrange it separately from the first positive component. Assuming that the first positive component and the second positive component as a whole have a certain refractive power, if the second positive component shares the positive refractive power in this way, the refractive power of the first positive component is relatively Get smaller. If the refractive power of the first positive component is reduced, a large amount of movement of the first positive component must be ensured during zooming, resulting in an increase in the overall length of the lens system.

  Thus, in a zoom lens having negative, positive, and positive component configurations, maintaining telecentricity and downsizing are contradictory conditions. On the other hand, when the solid-state imaging device as disclosed in Patent Documents 5 and 6 described above is used, the telecentricity required for the optical system is alleviated. It may not be the optimal solution.

  The present invention is intended for use in a solid-state imaging device in which required telecentricity is relaxed, and by appropriately performing a lens configuration and a lens group arrangement, a zoom lens that further reduces the overall lens system is provided. For the purpose of provision.

The zoom lens according to the first invention of the present application is a first lens group including a reflecting member for deflecting an optical path, a lens group having a positive refractive power disposed on the image side, and a negative refractive power disposed on the image side. It has a lens group. This lens unit having a negative refractive power is the lens unit disposed on the most image side among the lens groups included in the zoom lens. The focal length of the lens unit having the negative refractive power is fe, and all the lenses at the wide angle end are arranged. When the focal length of the system is fw,
0.8 <| fe / fw | <2.5
It satisfies the following condition.

  The zoom lens according to the second invention of the present application includes, in order from the object side to the image side, a first lens group having a positive or negative refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative lens group. A fourth lens unit having a refractive power of. The first lens group includes a positive refractive power component and a reflecting member that deflects the optical path.

  According to the present invention, a compact zoom lens can be realized.

  Embodiments of the zoom lens of the present invention and an image pickup apparatus having the same will be described below.

  FIGS. 1A to 1C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end of the zoom lens according to Embodiment 1, respectively. 2A to 2C are aberration diagrams of the zoom lens according to the first exemplary embodiment at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  3A to 3C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end of the zoom lens according to the second embodiment, respectively. 4A to 4C are aberration diagrams of the zoom lens of Example 2 at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  FIGS. 5A to 5C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the third exemplary embodiment. 6A to 6C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end of the zoom lens according to Embodiment 3, respectively.

  7A to 7C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the fourth exemplary embodiment. 8A to 8C are aberration diagrams of the zoom lens of Example 4 at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  FIGS. 9A to 9C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the fifth exemplary embodiment. 10A to 10C are aberration diagrams of the zoom lens of Example 5 at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  11A to 11C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the sixth exemplary embodiment. 12A to 12C are aberration diagrams of the zoom lens according to the sixth exemplary embodiment at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  FIGS. 13A to 13C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end of the zoom lens according to the seventh embodiment, respectively. FIGS. 14A to 14C are aberration diagrams of the zoom lens of Example 7 at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  FIGS. 15A to 15C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the eighth embodiment. FIGS. 16A to 16C are aberration diagrams respectively at the wide-angle end, the intermediate zoom position, and the telephoto end of the zoom lens according to the eighth embodiment.

  The zoom lens of each embodiment is a photographic lens system used in an imaging apparatus. In the lens cross-sectional view, the left side is the object side (front), and the right side is the image side (rear).

  In the lens cross-sectional view, Bi (i = 1, 2, 3, 4) is the i-th lens group. i means the i-th lens group counted from the object side. In this embodiment, each lens group is divided according to an interval that changes during zooming. SP is an aperture stop. The aperture stop SP is disposed on the object side of the second lens group counted from the image side. That is, in Example 1-7, it is arrange | positioned at the object side of 3rd lens group B3, In Example 8, it is arrange | positioned at the object side of 2nd lens group B2.

  In the zoom lenses of Examples 1 to 5, the first lens unit B1 having positive or negative refractive power (engineering power = reciprocal of focal length) and the second lens unit having negative refractive power are sequentially arranged from the object side to the image side. This is a four-unit zoom lens including B2, a third lens unit B3 having a positive refractive power, and a fourth lens unit B4 having a negative refractive power. In Examples 1 and 2, the first lens unit B1 has a positive refractive power. In Examples 3 to 5, the first lens unit B1 has negative refractive power.

  In the zoom lenses of Examples 6 and 7, in order from the object side to the image side, the first lens unit B1 having a negative refractive power, the second lens unit B2 having a positive or negative refractive power, and a third lens having a positive refractive power This is a four-unit zoom lens configured by a group B3 and a fourth lens unit B4 having negative refractive power. In Example 6, the second lens unit B2 has a negative refractive power. In Example 7, the second lens unit B2 has a positive refractive power.

  The zoom lens according to the eighth exemplary embodiment includes, in order from the object side to the image side, a first lens unit B1 having a negative refractive power, a second lens unit B2 having a positive refractive power, and a third lens unit B3 having a negative refractive power. 3 group zoom lens.

  P is a deflection member including a reflection surface for bending the optical path included in the first lens unit B1. The light path from the subject is bent at an approximately 90 ° optical path by the reflecting surface of the reflecting member P. For the reflecting member P, a prism having a reflecting surface or a surface reflecting mirror can be applied. In this embodiment, a prism is used as the reflecting member P.

  LP is an optical block corresponding to an optical filter, a face plate, a quartz low-pass filter, an infrared cut filter, and the like. IP is the image plane. When the zoom lens of each embodiment is used as an imaging optical system for a video camera or a digital still camera, an imaging surface of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is placed on the image plane IP.

  In the aberration diagrams, d and g are d-line and g-line, respectively. ΔM and ΔS are a meridional image plane and a sagittal image plane. The distortion is represented by the d line. The lateral chromatic aberration is represented by the g-line.

  In each embodiment, when zooming from the wide-angle end to the telephoto end, the lens units other than the first lens unit B1 move so that the distance between the lens units changes. The first lens unit B1 does not move for zooming.

  In Examples 1 to 5 and 7, the second lens unit B1 moves so as to draw a convex locus on the image side, and the third lens unit B3 and the fourth lens unit B4 move to the object side. In Example 6, the second lens unit B1 moves so as to draw a convex locus on the object side, and the third lens unit B3 and the fourth lens unit B4 move to the object side. In Example 8, the second lens unit B2 and the third lens unit B3 move to the object side.

  In each embodiment, focusing is performed by moving the lens unit disposed closest to the image side on the optical axis. That is, focusing is performed by the fourth lens unit B4 in Examples 1 to 7, and by the third lens unit B3 in Example 8.

  As described above, the zoom lens of each embodiment is provided with the reflecting member P (prism) for deflecting the optical path of the on-axis light beam by approximately 90 ° in the first lens unit B1. As a result, it is possible to reduce the thickness in the direction toward the subject of the lens system (the depth direction of the camera).

  Further, between the first lens unit B1 and the image plane, a lens unit having a positive refractive power (the third lens unit B3 in Examples 1 to 7, the second lens unit B2 in Example 8) and a negative refractive power. Lens groups (fourth lens group B4 in Examples 1 to 7, and third lens group B3 in Example 8) are arranged in this order. During zooming from the wide-angle end to the telephoto end, the positive lens group and the negative lens group move monotonously toward the object side while changing the interval. Thus, by sharing the role of zooming between the two lens groups having different signs of refractive power, the amount of movement required for zooming can be reduced and the total optical length can be shortened.

  Furthermore, in Examples 1 to 7, the second lens unit L2 is moved during zooming to compensate for image position fluctuations accompanying zooming. In addition, the second lens unit L2 effectively corrects aberrations during zooming.

  In the zoom lens of each embodiment, a negative lens group having a relatively strong refractive power is arranged on the most image side on the premise that a solid-state imaging device that does not require much telecentricity is used in the optical system. Thus, when a lens unit having a negative refractive power is arranged on the most image side in the optical system, the exit pupil position approaches the image plane, so that telecentricity is lowered. However, it is effective for shortening the optical total length.

However, as long as it is a solid-state imaging device, a certain degree of telecentricity is required. The aforementioned “relatively strong refractive power” is set in order to reduce the size of the zoom lens while taking into account the telecentricity required for the solid-state imaging device. That is, the focal length at the wide-angle end is fw, and the focal length of the lens unit having the negative refractive power arranged on the most image side (fourth lens unit B4 in Examples 1 to 7, and third lens unit B3 in Example 8). Is fe,
0.8 <| fe / fw | <2.5 (1)
Satisfy the following conditions.

  By appropriately setting the negative refracting power of the lens unit arranged closest to the image side in this way, it is possible to reduce the total lens length while suppressing the occurrence of various aberrations.

  When the lower limit of conditional expression (1) is exceeded, the refractive power of the lens unit disposed closest to the image side becomes excessively large, and hence it is impossible to maintain a good balance of various aberrations. In addition, since the exit pupil position is extremely close to the image plane, it is not suitable for use with a solid-state imaging device that does not require much telecentricity. Furthermore, the sensitivity to the assembly error (positional deviation) of the lens unit arranged on the most image side is increased, which is not preferable in manufacturing. On the other hand, if the upper limit of conditional expression (1) is exceeded, the refractive power of the lens unit disposed closest to the image side becomes weak, and the total lens length increases.

Further, regarding conditional expression (1), more preferably,
1.1 <| fe / fw | <2.0 (1a)
It is good to satisfy.

Further, since the lens group arranged closest to the image side shares the zooming as described above, it is preferable that the following condition is satisfied. That is, when the lateral magnifications at the wide-angle end and the telephoto end of the lens unit disposed closest to the image side (focusing on an infinitely distant object as the entire system) are βeW and βeT, respectively,
1.4 <βeT / βeW <3.0 (2)
It is preferable to satisfy the following conditions.

  The lens group on the most image side has a role of zooming as well as a role of imaging. By satisfying conditional expression (2), it is possible to suppress the amount of movement of the lens unit during zooming and the number of glass sheets in the entire lens system while maintaining good optical performance.

  Exceeding the upper limit of conditional expression (2) is effective for obtaining a zooming effect, but the refractive power of the lens unit disposed closest to the image side becomes too large. As a result, the sensitivity to the assembly error of the lens group is increased, which is not preferable in consideration of manufacturing. If the lower limit of the conditional expression (2) is exceeded, the variable magnification sharing of the lens group arranged closest to the image side becomes small, so that a desired zoom ratio cannot be ensured. Alternatively, in order to secure a desired zoom ratio, another moving lens group is inevitably added, and the entire optical system is enlarged.

Regarding conditional expression (2), more preferably 1.6 <βeT / βeW <2.2 (2a)
It is good to satisfy.

  Next, the configuration of each lens group will be described.

  In Examples 1 to 5, the first lens unit B1 includes at least one negative lens and at least one positive lens. Since the first lens unit B1 is a lens unit disposed closest to the object side, the lens diameter tends to be large. Thus, by using a negative lens and a positive lens, the lens diameter can be made as small as possible while suppressing various aberrations.

  In Examples 1 to 5, a positive meniscus lens having a convex surface on the image side is disposed closest to the image side of the first lens unit B1. By arranging the positive meniscus lens closest to the image side in this way, various aberrations generated by the negative lens located on the object side can be generated in the reverse direction and alleviated. In particular, the entire lens system is effective in favorably correcting astigmatism.

  In Examples 1 to 5, the first lens unit B1 is composed of, in order from the object side to the image side, a negative meniscus lens G11 having a convex surface on the object side, a right-angle prism P, and a positive meniscus lens G12 having a convex surface on the image side. Yes.

  In Examples 6 and 7, the first lens unit B1 is composed of the first lens G11 having a negative refractive power and the reflecting member P, which has an absolute value of the curvature on the image side larger than that on the object side in order from the object side to the image side. It is composed. However, the negative lens G11 may be integrated with the prism when a prism is used as the reflecting member. Furthermore, the entrance surface or exit surface of the prism may be processed into a concave surface having negative refractive power.

  In Example 8, in the first lens unit B1, in order from the object side to the image side, the curvature of the surface on the image side (the reciprocal of the radius of curvature) is larger than that on the object side, the negative lens G11, the reflecting member P, and the positive lens G12. It consists of. When using a prism for the reflecting member P, the negative lens G11 and the positive lens G12 may be joined and integrated with the prism. Furthermore, the incident surface of the prism may be processed into a concave shape having a negative refractive power, and the exit surface may be processed into a convex shape having a positive refractive power.

  In Examples 1 to 5, the second lens unit B2 has at least one biconcave lens. The second lens unit B2 of Examples 1 to 5 plays a role as a compensator. By providing a biconcave lens in the second lens group B2, it is possible to obtain a lens with a small number of refractive powers necessary for correcting various aberrations in the entire zooming area. Further, it is effective in correcting lateral chromatic aberration.

  In Examples 1 and 2, the second lens unit B2 includes, in order from the object side to the image side, a biconcave negative lens G21 and a positive meniscus lens having a convex surface on the object side. In Examples 3 to 5, the biconcave negative lens G21 and the positive meniscus lens G22 are cemented, and the second lens unit B2 is configured as a cemented lens having a negative refractive power as a whole.

  In Examples 6 and 7, the second lens unit B2 includes a cemented lens in which a negative lens and a positive lens are cemented. According to the second lens group B2 having such a configuration, it is possible to satisfactorily correct spherical aberration by suppressing variation in chromatic aberration during zooming.

  In Examples 1 to 5, the third lens unit B3 has at least one aspherical surface. This is for correcting aberrations efficiently with a small number of lenses. In this respect, it is preferable that the biconvex lens included in the third lens unit B3 is a double-sided aspheric surface. The aspherical lens may be selected from glass, plastic molded, cut, or a replica aspherical surface because a resin is attached to the glass surface.

  In Example 1, the third lens unit B3 includes, in order from the object side to the image side, a biconvex positive lens G31, a negative meniscus lens G32 having a convex image side, a biconvex positive lens G33, and an object side It is composed of a convex negative meniscus lens G34. The positive lens G31 and the negative meniscus lens G32 are cemented to constitute a cemented lens having a positive refractive power as a whole. In the biconvex positive lens G33, both the object-side and image-side surfaces are aspherical (double-sided aspherical). The negative meniscus lens G34 has an aspheric surface on the object side.

  In Examples 2 and 3, the third lens unit B3 includes, in order from the object side to the image side, a biconvex positive lens G31, a negative meniscus lens G32 having a convex surface on the image side, and a biconvex positive lens G33. It is composed of a biconcave negative lens G34. The positive lens G31 and the negative meniscus lens G32 are cemented to constitute a cemented lens having a positive refractive power as a whole. In the biconvex positive lens G33, both the object side surface and the image side surface are aspherical.

  In Example 4, the third lens unit B3 includes, in order from the object side to the image side, a biconvex positive lens G31, a negative meniscus lens G32 having a convex image side, a biconvex positive lens G33, and an object side It is composed of a convex negative meniscus lens G34. The positive lens G31 and the negative meniscus lens G32 are cemented to constitute a cemented lens having a positive refractive power as a whole. The negative meniscus lens G32 has an aspheric surface on the image side. In the biconvex positive lens G33, both the object side surface and the image side surface are aspherical.

  In Example 5, in order from the object side to the image side, the third lens unit B3 includes a positive meniscus lens G31 having a convex surface on the object side, a positive lens G32 having a biconvex shape, a negative meniscus lens G33 having a convex surface on the image side, The lens includes a convex positive lens G34 (double-sided aspheric surface) and a negative meniscus lens G35 (image-side surface is aspherical) having a convex surface on the object side. The positive lens G32 and the negative meniscus lens G33 are cemented to constitute a cemented lens having a positive refractive power as a whole. In the biconvex positive lens G34, both the object side surface and the image side surface are aspherical. The negative meniscus lens G35 has an aspheric surface on the image side.

  In Examples 6 and 7, the third lens unit B3 includes a positive lens component G31, a negative lens component G32, and a positive lens component G33 in order from the object side to the image side, and performs good aberration correction. Here, the lens component means a single lens or a cemented lens.

  In Example 8, the second lens unit B2 corresponds to the third lens unit of the other examples. The second lens unit B2 of Example 8 includes a positive lens component G21, a negative lens component G22, and a positive lens component G23 in order from the object side to the image side, and performs favorable aberration correction.

  In Examples 1 to 5, the fourth lens unit B4 includes only a negative meniscus lens G41 having a convex surface on the image side. By making the lens arranged closest to the image side into a negative meniscus shape having a convex surface on the image side, the lens has a shape close to a concentric shape with respect to the aperture stop SP. Thereby, the total length can be shortened while suppressing the occurrence of aberration.

  In Examples 6 and 7, the fourth lens unit B4 is composed of two negative lenses. However, in Examples 6 and 7, the fourth lens group may be composed of a single negative lens. When the fourth lens unit B4 is composed of a single negative lens, it is desirable that the lens shape be such that the curvature of the lens surface on the image side is larger than that on the object side. In order to improve image quality, a negative lens having a concave lens surface on the image side is disposed on the object side of the lens having the aspheric surface on the object side in the fourth lens unit B4. preferable.

  In Example 8, the third lens unit B3 corresponds to the fourth lens unit of the other examples. The third lens unit B3 in Example 8 includes a positive lens and a negative lens. However, it may be composed of one negative lens. When the third lens unit B3 is composed of a single negative lens, it is desirable to have a lens shape in which the curvature of the lens surface on the image side is larger than that on the object side. In order to achieve high image quality, it is preferable to dispose a negative lens having a concave lens surface on the image side on the object side of the lens having an aspheric surface on the object side in the third lens unit B3. .

  Next, numerical examples of Examples 1 to 8 will be shown. In each numerical example, i indicates the order of the surfaces from the object side, Ri is the radius of curvature of each surface, Di is the distance between the i-th surface and the (i + 1) -th surface, and Ni and νi are d-lines, respectively. The refractive index and Abbe number are shown with reference to.

The two surfaces closest to the image are surfaces constituting the optical block LP. Further, the aspherical shape means that when the displacement in the optical axis direction at the position of the height h from the optical axis is x with respect to the surface vertex,
x = (h ² / R) / [1+ {1− (1 + k) (h / R) ² } ^1/2 ]
+ Ah ² + Bh ⁴ + Ch ⁶ + Dh ⁸ + Eh ¹⁰
It is represented by Here, k is a conic constant, A, B, C, D, and E are aspheric coefficients, and R is a paraxial radius of curvature.

“E-0X” means “× 10 ^−x ”. f represents a focal length, Fno represents an F number, and ω represents a half angle of view. Table 1 shows the relationship between the above-described conditional expressions and numerical examples.

(Numerical example 1)
f = 6.3−23.3 Fno = 2.4−5.7 ω = 29.3−8.5 °
R1 = 18.611 D1 = 0.850 N1 = 1.9229 ν1 = 18.9
R2 = 10.025 D2 = 2.221
R3 = ∞ D3 = 10.200 N2 = 1.8040 ν2 = 46.6
R4 = ∞ D4 = 0.490
R5 = -38.404 D5 = 1.180 N3 = 1.6990 ν3 = 30.1
R6 = -14.412 D6 = variable
R7 = -12.722 D7 = 0.400 N4 = 1.7440 ν4 = 44.8
R8 = 14.684 D8 = 0.200
R9 = 13.385 D9 = 1.234 N5 = 1.9229 ν5 = 18.9
R10 = 85.033 D10 = variable
R11 = 6.786 D11 = 3.405 N6 = 1.4875 ν6 = 70.2
R12 = -6.200 D12 = 0.350 N7 = 1.8340 ν7 = 37.2
* R13 = -54.737 D13 = 0.285
* R14 = 7.224 D14 = 2.307 N8 = 1.4875 ν8 = 70.2
* R15 = -6.588 D15 = 0.050
R16 = 7.601 D16 = 0.800 N9 = 1.8340 ν9 = 37.2
R17 = 4.467 D17 = Variable
R18 = -5.991 D18 = 0.500 N10 = 1.8340 ν10 = 37.2
R19 = -19.654 D19 = variable
R20 = ∞ D20 = 0.600 N11 = 1.5163 ν11 = 64.1
R21 = ∞

/ Focal length Wide Middle Tele
Variable interval /
D6 0.521 4.808 1.762
D10 11.962 3.713 0.255
D17 7.311 6.290 5.677
D19 0.200 5.183 12.300

Aspheric coefficient
13 planes k = 0
A = 0 B = 1.5464e-04 C = 2.3539e-05 D = 1.4487e-06 E = -5.7241e-08
14 faces k = 0
A = 0 B = -1.4805e-03 C = -5.0395e-06 D = 1.7754e-06 E = -1.2369e-08
15 faces k = 0
A = 0 B = 4.1729e-04 C = -4.3939e-05 D = 2.5998e-06 E = -2.8596e-08

(Numerical example 2)
f = 6.3−18.9 Fno = 2.4−5.0 ω = 29.3−10.5 °
R1 = 15.924 D1 = 0.850 N1 = 1.9229 ν1 = 18.9
R2 = 8.910 D2 = 2.500
R3 = ∞ D3 = 11.000 N2 = 1.8040 ν2 = 46.6
R4 = ∞ D4 = 0.678
R5 = -23.391 D5 = 1.177 N3 = 1.7552 ν3 = 27.5
R6 = -11.961 D6 = variable
R7 = -10.497 D7 = 0.400 N4 = 1.6223 ν4 = 53.2
R8 = 12.206 D8 = 0.330
R9 = 11.620 D9 = 1.800 N5 = 1.8467 ν5 = 23.8
R10 = 59.986 D10 = variable
R11 = 6.292 D11 = 3.500 N6 = 1.4875 ν6 = 70.2
R12 = -6.754 D12 = 0.380 N7 = 1.8340 ν7 = 37.2
R13 = -31.948 D13 = 0.200
* R14 = 8.673 D14 = 2.222 N8 = 1.4875 ν8 = 70.2
* R15 = -6.441 D15 = 0.085
R16 = -18.741 D16 = 0.800 N9 = 1.8340 ν9 = 37.2
R17 = 30.053 D17 = variable
R18 = -4.500 D18 = 0.500 N10 = 1.8340 ν10 = 37.2
R19 = -10.130 D19 = variable
R20 = ∞ D20 = 0.600 N11 = 1.5163 ν11 = 64.1
R21 = ∞

/ Focal length Wide Middle Tele
Variable interval /
D6 0.538 4.630 2.984
D10 11.323 3.560 0.977
D17 7.713 6.817 6.255
D19 0.200 4.767 9.558

Aspheric coefficient
14 faces k = 0
A = 0 B = -7.8721e-04 C = -3.1700e-05 D = 6.1625e-07 E = -1.0793e-07
15 faces k = 0
A = 0 B = 1.1193e-03 C = -3.4844e-05 D = 1.3647e-06 E = -9.4562e-08

(Numerical Example 3)
f = 6.3−22.1 Fno = 2.4−5.6 ω = 29.3−9.0 °
R1 = 16.819 D1 = 0.900 N1 = 1.9229 ν1 = 18.9
R2 = 9.713 D2 = 2.357
R3 = ∞ D3 = 10.500 N2 = 1.8040 ν2 = 46.6
R4 = ∞ D4 = 0.690
R5 = -22.261 D5 = 1.027 N3 = 1.8467 ν3 = 23.8
R6 = -13.462 D6 = variable
R7 = -10.158 D7 = 0.550 N4 = 1.6393 ν4 = 44.9
R8 = 9.102 D8 = 1.385 N5 = 1.8467 ν5 = 23.8
R9 = 71.000 D9 = 0.000
R10 = ∞ D10 = variable
R11 = 5.523 D11 = 3.231 N6 = 1.4875 ν6 = 70.2
R12 = -6.804 D12 = 0.320 N7 = 1.8340 ν7 = 37.2
R13 = -38.825 D13 = 0.267
* R14 = 8.372 D14 = 1.991 N8 = 1.4875 ν8 = 70.2
* R15 = -6.012 D15 = 0.050
R16 = -18.912 D16 = 1.438 N9 = 1.8340 ν9 = 37.2
R17 = 23.920 D17 = variable
R18 = -4.599 D18 = 0.500 N10 = 1.8348 ν10 = 42.7
R19 = -11.103 D19 = variable
R20 = ∞ D20 = 0.600 N11 = 1.5163 ν11 = 64.1
R21 = ∞

/ Focal length Wide Middle Tele
Variable interval /
D6 1.284 4.784 2.160
D10 10.395 3.296 0.200
D17 6.708 6.116 5.749
D19 0.200 4.392 10.478

Aspheric coefficient
14 faces k = 0
A = 0 B = -1.3486e-03 C = -3.9246e-05 D = -3.9584e-06 E = 1.2667e-07
15 faces k = 0
A = 0 B = 1.2971e-03 C = -4.6161e-05 D = -7.7310e-07 E = 8.0469e-08

(Numerical example 4)
f = 6.3−18.9 Fno = 2.5−5.3 ω = 29.3−10.5 °
R1 = 20.645 D1 = 0.900 N1 = 1.9229 ν1 = 18.9
R2 = 9.782 D2 = 1.700
R3 = ∞ D3 = 10.500 N2 = 1.8040 ν2 = 46.6
R4 = ∞ D4 = 0.347
R5 = -50.851 D5 = 0.979 N3 = 1.8467 ν3 = 23.8
R6 = -17.125 D6 = variable
R7 = -11.058 D7 = 0.550 N4 = 1.7015 ν4 = 41.2
R8 = 7.116 D8 = 1.577 N5 = 1.8467 ν5 = 23.8
R9 = 67.121 D9 = variable
R10 = 5.278 D10 = 3.260 N6 = 1.4875 ν6 = 70.2
R11 = -5.803 D11 = 0.300 N7 = 1.8340 ν7 = 37.2
* R12 = -89.923 D12 = 0.200
* R13 = 6.225 D13 = 2.332 N8 = 1.4875 ν8 = 70.2
* R14 = -5.699 D14 = 0.069
R15 = 28.539 D15 = 0.801 N9 = 1.8340 ν9 = 37.2
* R16 = 8.006 D16 = Variable
R17 = -5.316 D17 = 0.500 N10 = 1.8348 ν10 = 42.7
R18 = -24.116 D18 = variable
R19 = ∞ D19 = 0.600 N11 = 1.5163 ν11 = 64.1
R20 = ∞

/ Focal length Wide Middle Tele
Variable interval /
D6 0.672 2.516 0.408
D9 7.683 2.108 0.200
D16 5.545 4.820 4.479
D18 0.596 5.051 9.409

Aspheric coefficient
12 faces k = 0
A = 0 B = 4.7500e-04 C = 1.1886e-05 D = -2.2869e-06 E = 2.3746e-07
13 planes k = 0
A = 0 B = -1.0867e-03 C = -5.8280e-05 D = -7.2467e-06 E = 1.2741e-07
14 faces k = 0
A = 0 B = 8.9802e-04 C = -6.8994e-05 D = 1.1690e-06 E = -1.7331e-07
16 faces k = 0
A = 0 B = 1.0330e-03 C = 5.9134e-05 D = 2.8816e-06 E = -7.2933e-07

(Numerical example 5)
f = 6.3−22.7 Fno = 2.4−5.8 ω = 29.3−8.8 °
R1 = 17.853 D1 = 0.850 N1 = 1.9229 ν1 = 18.9
R2 = 9.459 D2 = 2.345
R3 = ∞ D3 = 10.200 N2 = 1.8467 ν2 = 23.8
R4 = ∞ D4 = 0.706
R5 = -23.541 D5 = 1.113 N3 = 1.8052 ν3 = 25.4
R6 = -13.196 D6 = variable
R7 = -10.806 D7 = 0.400 N4 = 1.6177 ν4 = 49.8
R8 = 9.219 D8 = 1.256 N5 = 1.8467 ν5 = 23.8
R9 = 52.946 D9 = variable
R10 = 9.977 D10 = 0.900 N6 = 1.5163 ν6 = 64.1
R11 = 11.321 D11 = 0.050
R12 = 6.284 D12 = 3.074 N7 = 1.4875 ν7 = 70.2
R13 = -6.819 D13 = 0.320 N8 = 1.8340 ν8 = 37.2
R14 = -11015.044 D14 = 0.200
* R15 = 7.549 D15 = 2.589 N9 = 1.4875 ν9 = 70.2
* R16 = -6.325 D16 = 0.175
R17 = -390.475 D17 = 2.000 N10 = 1.8340 ν10 = 37.2
* R18 = 13.185 D18 = variable
R19 = -6.148 D19 = 0.500 N11 = 1.8040 ν11 = 46.6
R20 = -21.695 D20 = variable
R21 = ∞ D21 = 0.600 N12 = 1.5163 ν12 = 64.1
R22 = ∞

/ Focal length Wide Middle Tele
Variable interval /
D6 1.672 4.928 1.559
D9 10.421 3.328 0.100
D18 6.329 5.369 4.781
D20 0.200 4.997 12.182

Aspheric coefficient
15 faces k = 0
A = 0 B = -8.8222e-04 C = -2.4577e-05 D = -1.1520e-06 E = -1.1257e-07
16 faces k = 0
A = 0 B = 1.4185e-03 C = -8.4337e-05 D = 2.5229e-06 E = -1.2053e-07
18 faces k = 0
A = 0 B = 3.0022e-04 C = 6.2597e-05 D = 1.2883e-06 E = -2.7774e-07

(Numerical example 6)
f = 5.82 to 15.50 Fno = 2.34 to 5.00 2ω = 54.6 to 21.9
R 1 = 17.420 D 1 = 0.80 N 1 = 1.696797 ν 1 = 55.5
R 2 = 9.165 D 2 = 2.50
R 3 = ∞ D 3 = 6.50 N 2 = 1.696797 ν 2 = 55.5
R 4 = ∞ D 4 = Variable
R 5 = -13.555 D 5 = 0.70 N 3 = 1.696797 ν 3 = 55.5
R 6 = 50.746 D 6 = 1.30 N 4 = 1.834000 ν 4 = 37.2
R 7 = -22.278 D 7 = variable
R 8 = Aperture D 8 = 0.70
R 9 = 5.953 D 9 = 1.70 N 5 = 1.733997 ν 5 = 51.5
R10 = 20.439 D10 = 0.25
R11 = -13.273 D11 = 1.70 N 6 = 1.719995 ν 6 = 50.2
R12 = -3.864 D12 = 0.60 N 7 = 1.800999 ν 7 = 35.0
R13 = -38.096 D13 = 0.20
* R14 = 13.106 D14 = 1.70 N 8 = 1.487490 ν 8 = 70.2
* R15 = -4.634 D15 = variable
* R16 = 159.392 D16 = 1.50 N 9 = 1.491710 ν 9 = 57.4
* R17 = 112.510 D17 = 0.60
R18 = -3.771 D18 = 0.70 N10 = 1.729157 ν10 = 54.7
R19 = -18.062 D19 = variable
R20 = ∞ D20 = 0.60 N11 = 1.516330 ν11 = 64.1
R21 = ∞

\ Focal length 5.82 10.46 15.50
Variable interval \
D 4 2.51 0.73 1.19
D 7 7.30 5.16 0.80
D15 2.68 0.97 0.49
D19 1.00 6.62 11.01

Aspheric coefficient
14th: k = -2.39711e + 01
A = 0 B = -2.63697e-03 C = -3.10017e-04 D = -2.70261e-06 E = -6.08507e-06
15th: k = 3.75824e-01
A = 0 B = 3.45097e-04 C = -1.78596e-04 D = 1.09833e-05 E = -4.36814e-06
16 sides: k = -4.70761e + 06
A = 0 B = 6.47376e-03 C = -2.44585e-04 D = 1.35856e-04 E = -1.02447e-05
17th: k = -3.93361e + 06
A = 0 B = 5.70058e-03 C = 2.84537e-04 D = -2.77559e-05 E = 2.99998e-05

(Numerical example 7)
f = 5.63 to 16.80 Fno = 2.08 to 5.00 2ω = 56.1 to 20.2
R 1 = 48.153 D 1 = 0.80 N 1 = 1.603112 ν 1 = 60.6
R 2 = 11.083 D 2 = 2.30
R 3 = ∞ D 3 = 10.00 N 2 = 1.772499 ν 2 = 49.6
R 4 = ∞ D 4 = Variable
R 5 = 199.961 D 5 = 0.70 N 3 = 1.772499 ν 3 = 49.6
R 6 = 22.845 D 6 = 1.40 N 4 = 1.805181 ν 4 = 25.4
R 7 = 242.865 D 7 = variable
R 8 = Aperture D 8 = 0.70
R 9 = 5.245 D 9 = 2.00 N 5 = 1.487490 ν 5 = 70.2
R10 = -35.017 D10 = 0.25
R11 = -12.568 D11 = 1.70 N 6 = 1.719995 ν 6 = 50.2
R12 = -3.940 D12 = 0.60 N 7 = 1.834000 ν 7 = 37.2
R13 = -109.961 D13 = 0.50
* R14 = 18.634 D14 = 2.00 N 8 = 1.583126 ν 8 = 59.4
* R15 = -5.135 D15 = variable
* R16 = 151.895 D16 = 1.20 N 9 = 1.749497 ν 9 = 35.3
* R17 = 121.189 D17 = 1.00
R18 = -3.555 D18 = 0.70 N10 = 1.729157 ν10 = 54.7
R19 = -20.295 D19 = variable
R20 = ∞ D20 = 0.60 N11 = 1.516330 ν11 = 64.1
R21 = ∞

\ Focal length 5.63 11.07 16.80
Variable interval \
D 4 0.95 2.52 1.84
D 7 10.69 4.61 0.80
D15 2.77 0.98 0.51
D19 0.70 6.99 11.96

Aspheric coefficient
14th: k = 1.66335e + 01
A = 0 B = -3.21818e-03 C = -1.86168e-04 D = 5.40611e-06 E = -2.02531e-06
15th: k = 2.53718e-01
A = 0 B = 3.69525e-04 C = -1.49964e-04 D = 1.18370e-05 E = -1.34525e-06
16 sides: k = -5.25720e + 06
A = 0 B = 5.24497e-03 C = -1.79913e-04 D = 7.42054e-05 E = -3.94180e-06
17th: k = -3.87782e + 06
A = 0 B = 4.24203e-03 C = 4.38752e-05 D = 2.06324e-05 E = 5.70011e-06

(Numerical example 8)
f = 5.81 to 11.62 Fno = 2.58 to 5.00 2ω = 54.6 to 28.9
R 1 = 31.228 D 1 = 0.80 N 1 = 1.696797 ν 1 = 55.5
R 2 = 6.560 D 2 = 2.50
R 3 = ∞ D 3 = 7.50 N 2 = 1.696797 ν 2 = 55.5
R 4 = ∞ D 4 = 0.20
R 5 = 17.090 D 5 = 1.70 N 3 = 1.719995 ν 3 = 50.2
R 6 = -184.750 D 6 = variable
R 7 = Aperture D 7 = 0.70
R 8 = 8.734 D 8 = 1.70 N 4 = 1.733997 ν 4 = 51.5
R 9 = 20.421 D 9 = 0.40
R10 = 34.530 D10 = 1.70 N 5 = 1.719995 ν 5 = 50.2
R11 = -8.541 D11 = 0.60 N 6 = 1.800999 ν 6 = 35.0
R12 = 12.151 D12 = 0.20
* R13 = 7.827 D13 = 1.70 N 7 = 1.487490 ν 7 = 70.2
* R14 = -4.744 D14 = Variable
* R15 = 926.758 D15 = 1.50 N 8 = 1.749497 ν 8 = 35.3
* R16 = -1871.398 D16 = 0.50
R17 = -7.786 D17 = 0.70 N 9 = 1.729157 ν 9 = 54.7
R18 = 12.012 D18 = variable
R19 = ∞ D19 = 0.60 N10 = 1.516330 ν10 = 64.1
R20 = ∞

\ Focal length 5.81 8.13 11.62
Variable interval \
D 6 6.18 4.45 0.98
D14 2.93 1.53 0.49
D18 0.50 3.64 8.14

Aspheric coefficient
13th: k = -1.46645e + 01 A = 0 B = -6.87569e-04 C = -6.88440e-04
D = -3.51490e-05 E = -1.21669e-05
14th: k = 7.03414e-01 A = 0 B = 1.17600e-04 C = -4.53702e-04
D = 1.23625e-05 E = -8.60067e-06
15th: k = -4.70761e + 06 A = 0 B = 4.09016e-03 C = -4.72506e-04
D = 1.62987e-04 E = -1.49799e-05
16 sides: k = -3.93361e + 06 A = 0 B = 4.73146e-03 C = -5.89916e-05
D = 1.00802e-04 E = -2.00945e-06

  Thus, according to the zoom lenses of Examples 1 to 8, a small zoom lens can be realized.

  Next, an embodiment of a digital still camera using the zoom lens of the present invention as a photographing optical system will be described with reference to FIG.

  In FIG. 17, reference numeral 10 denotes a digital camera body, 11 denotes a photographing optical system constituted by the zoom lens of the present invention, 12 denotes a strobe built in the camera body, 13 denotes an external finder, and 14 denotes a shutter button. Reference numeral 15 denotes a schematic arrangement of the optical system in the camera body of the zoom lens of the present invention.

  In this way, by applying the zoom lens of the present invention to an image pickup apparatus such as a digital camera, a small-size image pickup apparatus having high optical performance is realized, in particular, the camera body can be thinned.

  In this example, the optical system is arranged so that the optical axis deflected by the reflecting member is in the vertical (vertical) direction, but the optical system is arranged so that the deflected optical axis is in the horizontal (horizontal) direction. You may do it.

  The zoom lens of the present invention can be applied to an imaging unit incorporated in a mobile phone, a personal computer, a portable terminal, etc. in addition to an imaging device such as a digital still camera and a digital video camera.

3 is a cross-sectional view of the zoom lens of Example 1. FIG. FIG. 3 is an aberration diagram of the zoom lens according to Example 1; 6 is a cross-sectional view of a zoom lens according to Example 2. FIG. FIG. 6 is an aberration diagram of the zoom lens according to Example 2; 6 is a cross-sectional view of a zoom lens of Example 3. FIG. FIG. 6 is an aberration diagram of the zoom lens according to Example 3; 6 is a cross-sectional view of a zoom lens according to Example 4. FIG. FIG. 6 is an aberration diagram of the zoom lens according to Example 4; 6 is a cross-sectional view of a zoom lens according to Example 5. FIG. FIG. 10 is an aberration diagram of the zoom lens according to Example 5; 10 is a cross-sectional view of a zoom lens according to Example 6. FIG. FIG. 10 is an aberration diagram of the zoom lens according to Example 6; 10 is a cross-sectional view of a zoom lens according to Example 7. FIG. 10 is an aberration diagram of the zoom lens according to Example 7. FIG. 10 is a cross-sectional view of a zoom lens according to Example 8. FIG. FIG. 10 is an aberration diagram of the zoom lens according to Example 8; It is a principal part schematic diagram of an imaging device.

Explanation of symbols

B1 First lens group B2 Second lens group B3 Third lens group B4 Fourth lens group P Reflective member SP Aperture stop LP Optical block IP Image surface

Claims (19)

A first lens group including a reflecting member for deflecting the optical path; a positive refractive power lens group disposed on the image side of the first lens group; and a negative refractive index disposed on the image side of the positive refractive power lens group. A lens unit having a refractive power, and during zooming from the wide-angle end to the telephoto end, an interval between the first lens unit and the lens unit having the positive refractive power, and the lens unit having the positive refractive power and the negative refraction; A zoom lens in which an interval between the power lens groups is changed, and the lens group having the negative refractive power is a lens group arranged closest to the image side among the lens groups included in the zoom lens; When the focal length of the lens unit having a refractive power of f is fe and the focal length of the entire system at the wide angle end is fw,
0.8 <| fe / fw | <2.5
A zoom lens characterized by satisfying the following conditions: When the lateral magnification at the wide-angle end of the negative refractive power lens group is βew, and the lateral magnification at the telephoto end of the negative refractive power lens group is βeT,
1.4 <βeT / βeW <3.0
The zoom lens according to claim 1, wherein the following condition is satisfied.   3. The zoom lens according to claim 1, wherein the positive refractive power lens group and the negative refractive power lens group move together toward the object side during zooming from the wide-angle end to the telephoto end.   The zoom lens according to claim 1, wherein the first lens group includes a negative lens and a positive lens.   The first lens group includes a positive meniscus lens having a convex surface on the image side, and the positive meniscus lens is a lens disposed closest to the image side in the first lens group. 4 Any zoom lens.   The zoom lens according to claim 1, wherein the lens having the negative refractive power lens group is only a negative meniscus lens having a convex surface on the image side.   In order from the object side to the image side, the first lens group having a positive or negative refractive power, the second lens group having a negative refractive power, the third lens group that is a lens group having the positive refractive power, and the negative refraction. Only the four lens groups of the fourth lens group, which is a power lens group, are provided as lens groups, and during zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group, the second lens group The zoom lens according to any one of claims 1 to 6, wherein an interval between the first lens group and the third lens group and an interval between the third lens group and the fourth lens group are changed.   In order from the object side to the image side, the first lens group having a negative refractive power, the second lens group having a positive or negative refractive power, the third lens group that is a lens group having the positive refractive power, and the negative refraction. Only the four lens groups of the fourth lens group, which is a power lens group, are provided as lens groups, and during zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group, the second lens group 4. The zoom lens according to claim 1, wherein an interval between the first lens group and the third lens group and an interval between the third lens group and the fourth lens group are changed.   In order from the object side to the image side, the first lens group having a negative refractive power, the second lens group being a lens group having a positive refractive power, and the third lens group being a lens group having a negative refractive power. It has only one lens group as a lens group, and the distance between the first lens group and the second lens group and the distance between the second lens group and the third lens group change during zooming from the wide-angle end to the telephoto end. The zoom lens according to any one of claims 1 to 3.   In order from the object side to the image side, a first lens group having a positive or negative refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a negative refractive power; And during zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, the third lens group and the fourth lens group The zoom lens is characterized in that the first lens group has a positive refractive power component and a reflecting member that deflects the optical path. When the focal length of the fourth lens group is fe and the focal length of the entire system at the wide angle end is fw,
0.8 <| fe / fw | <2.5
The zoom lens according to claim 10, wherein the following condition is satisfied. When the lateral magnification at the wide-angle end of the fourth lens group is βew and the lateral magnification at the telephoto end of the fourth lens group is βeT,
1.4 <βeT / βeW <3.0
The zoom lens according to claim 10 or 11, wherein the following condition is satisfied.   The zoom lens according to any one of claims 10 to 12, wherein the third lens group and the fourth lens group both move toward the object side during zooming from the wide-angle end to the telephoto end.   The zoom lens according to claim 10, wherein the first lens group further has a negative refractive power component.   11. The first lens group includes a positive meniscus lens having a convex surface on the image side, and the positive meniscus lens is a lens disposed closest to the image side in the first lens group. 14 any zoom lens.   The zoom lens according to claim 10, wherein the second lens group includes a biconcave lens.   The zoom lens according to any one of claims 10 to 16, wherein a lens included in the fourth lens group is only a negative meniscus lens having a convex surface on the image side.   The zoom lens according to claim 1, wherein an image is formed on a solid-state imaging device. An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image pickup device that receives an image formed by the zoom lens.

Images