JP2012194278A - Zoom lens and imaging apparatus - Google Patents

Abstract

The present invention aims to achieve a wide angle and high magnification while having a small size and good optical performance over the entire zoom range.
A first lens group GR1 having a positive refractive power, a second lens group GR2 having a negative refractive power, a third lens group GR3 having a positive refractive power, and a fourth lens group having a positive refractive power. GR4 and a fifth lens group GR5 having positive refractive power are arranged in order from the object side to the image side, and the first lens group is separated from the second lens group during zooming from the wide-angle end to the telephoto end. The third lens group moves toward the object side so as to approach the second lens group, the fourth lens group moves toward the object side so as to approach the third lens group, and the following conditional expression Satisfy (1). (1) 4.5 <100 × D (T, 2-3) / fW <15, where D (T, 2-3): the surface closest to the image side of the second lens group at the telephoto end and the third lens The distance on the optical axis from the most object-side surface of the group, fW: the focal length of the entire optical system at the wide-angle end.
[Selection] Figure 1

Description

  The present technology relates to a zoom lens and an imaging apparatus. Specifically, the technical field of a zoom lens suitably used for a digital still camera, a video camera, a surveillance camera and the like having a high zoom magnification and a sufficiently wide angle of view, and an imaging device including the zoom lens About.

  In recent years, the market for imaging devices such as digital cameras has become very large, and the demands of users for digital cameras and the like are diverse. For example, there is a growing demand for higher magnification, brightness, and wider angle of the photographic lens, not to mention higher image quality, smaller size, and thinner thickness.

  In general, the so-called positive lead type zoom lens in which the most object side lens group has a positive refractive power among the zoom lenses provided in the imaging apparatus has an advantage that the zoom magnification can be increased and an optical system in the entire zoom region. There is an advantage that it can be designed brightly. Accordingly, a positive lead type zoom lens is often used as one suitable for a high magnification type in which the zoom magnification exceeds 10 times, for example.

  As such a positive lead type zoom lens, there is a zoom lens having a five-group configuration having positive, negative, positive and positive refractive powers in order from the object side to the image side (see, for example, Patent Document 1 and Patent Document 2).

JP 2007-286446 A JP 2005-345968 A

  However, in the zoom lenses described in Patent Document 1 and Patent Document 2, neither sufficiently high magnification has been achieved, and the zoom lens is disposed closest to the object side when widening the angle. Since the lens has a characteristic that the outer diameter of the lens is easily increased, it has not been possible to realize a sufficiently wide angle and a small size of the field of view.

  Generally, an optical design that corrects aberrations and reduces error sensitivity at the time of manufacture is necessary for widening and increasing the magnification of the optical system, so the number of lenses is increased or the total length of the optical system is increased. Must be increased.

  From this point of view, even in the zoom lenses described in Patent Document 1 and Patent Document 2, the total optical length accompanying the increase in the number of lenses in the second lens group and the third lens group and the increase in the stroke during zooming. Therefore, it is necessary to increase the size of the device, and sufficient size reduction has not been realized.

  In particular, in the so-called collapsible zoom lens, the lens is retracted when not in use (non-photographing) to achieve good storage, so the number and thickness of the lenses are reduced, and the stroke during zooming is shortened. It is extremely difficult to reduce the overall thickness. Therefore, there is a high need for a compact zoom lens as well as higher magnification and wider angle.

  In addition, in an image pickup apparatus using a solid-state image pickup device, a zoom lens with an image side close to telecentricity is desirable because the image surface illuminance can be made uniform. As such a zoom lens, the lens group closest to the image side is positively refracted. It is desirable to have power.

  Therefore, it is an object of the present technology zoom lens and imaging apparatus to overcome the above-described problems and achieve a wide angle and a high magnification while being compact and having good optical performance over the entire zoom range.

In order to solve the above-described problem, the zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive refractive power. And a fifth lens group having a positive refractive power are arranged in order from the object side to the image side. When zooming from the wide angle end to the telephoto end, the first lens group Move toward the object side away from the second lens group, move toward the object side so that the third lens group approaches the second lens group, and approach the fourth lens group toward the third lens group It moves to the object side and satisfies the following conditional expression (1).
(1) 4.5 <100 × D (T, 2-3) / fW <15
However,
D (T, 2-3): Distance on the optical axis between the most image side surface of the second lens group and the most object side surface of the third lens group at the telephoto end fW: focal point of all optical systems at the wide angle end Distance.

  Accordingly, in the zoom lens, the zooming effect of the second lens group to the fourth lens group is increased, and the most image side surface of the second lens group and the most object side of the third lens group at the telephoto end. The distance on the optical axis from the surface is optimized.

In the zoom lens described above, the third lens group includes at least two lenses, and at least one air space formed between the lenses exists in the third lens group. The following conditional expression (2) It is desirable to satisfy
(2) 2.0 <d (3, air) / D (T, 2-3)
However,
d (3, air): The air interval that is the largest in the optical axis direction among the air intervals existing in the third lens group.

  When the third lens group has at least one air gap formed between the lenses and satisfies the conditional expression (2), each refractive power of the lens (lens group) positioned opposite to the air gap is determined. While being optimized, error sensitivity is reduced.

  In the zoom lens described above, the third lens group includes at least two lenses, and the third lens group includes at least one air gap formed between the lenses. It is desirable to arrange a shutter mechanism having a function of shielding light at intervals.

  By disposing a shutter mechanism having a function of blocking light rays in the air interval of the third lens group, the movement stroke of the lens group during zooming becomes longer.

  In the zoom lens described above, the third lens group includes at least two lenses, and the third lens group includes at least one air gap formed between the lenses. The object-side surface of the lens disposed on the object side is formed in a convex shape, the vertex of the object-side surface of the lens disposed closest to the object side of the third lens group and the most image side of the third lens group It is desirable to dispose an F number determining member for determining an F number light flux in the air gap existing between the lens disposed on the image side and the apex on the image side.

  An air gap existing between the vertex of the object side surface of the lens disposed closest to the object side of the third lens group and the image side vertex of the lens disposed closest to the image side of the third lens group is represented by F By disposing the F-number determining member that determines the luminous flux of the number, the movement stroke of the lens group during zooming becomes longer.

In the zoom lens described above, it is preferable that the following conditional expression (3) is satisfied.
(3) 5.0 <100 × D (T, 3-4) / fW <20
However,
D (T, 3-4): The distance on the optical axis between the most image side surface of the third lens group and the most object side surface of the fourth lens group.

  When the zoom lens satisfies the conditional expression (3), the distance on the optical axis between the most image side surface of the second lens unit and the most object side surface of the third lens unit at the telephoto end is optimized. .

  In the zoom lens described above, it is preferable that the third lens group includes three lenses, a positive lens, a positive lens, and a negative lens, which are arranged in order from the object side to the image side.

  The third lens group is composed of three lenses, a positive lens, a positive lens, and a negative lens arranged in order from the object side to the image side, so that the principal point position on the image side of the third lens group is the object side. Get closer to.

In the zoom lens described above, it is preferable that the following conditional expression (4) is satisfied.
(4) 2.5 <f3 / fW <4.0
However,
f3: The focal length of the third lens group.

  When the zoom lens satisfies the conditional expression (4), the refractive power of the third lens group is optimized.

  In the zoom lens described above, it is preferable that the second lens group includes three lenses, a negative lens, a negative lens, and a positive lens, which are arranged in order from the object side to the image side.

  The second lens group is composed of three lenses, a negative lens, a negative lens, and a positive lens arranged in order from the object side to the image side, so that the principal point position on the image side of the second lens group is the object side. Get closer to.

In the zoom lens described above, it is preferable that the following conditional expression (5) is satisfied.
(5) 4.2 <[D (W, 2-4) -D (T, 2-4)] / fW <5.6
However,
D (W, 2-4): Distance on the optical axis between the most object side surface of the second lens group and the most image side surface of the fourth lens group at the wide angle end D (T, 2-4): wide angle The distance on the optical axis between the most object side surface of the second lens group and the most image side surface of the fourth lens group at the end.

  When the zoom lens satisfies the conditional expression (5), the distance on the optical axis between the most image side surface of the second lens unit and the most object side surface of the third lens unit at the telephoto end is optimized. .

In order to solve the above-described problem, the imaging apparatus includes a zoom lens and an imaging element that converts an optical image formed by the zoom lens into an electrical signal, and the zoom lens has a first refractive power. One lens group, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and a fifth lens group having positive refractive power are objects. The first lens unit moves to the object side so as to move away from the second lens unit during zooming from the wide-angle end to the telephoto end, and the third lens unit The lens moves toward the object side so as to approach the second lens group, and the fourth lens group moves toward the object side so as to approach the third lens group, and satisfies the following conditional expression (1).
(1) 4.5 <100 × D (T, 2-3) / fW <15
However,
D (T, 2-3): Distance on the optical axis between the most image side surface of the second lens group and the most object side surface of the third lens group at the telephoto end fW: focal point of all optical systems at the wide angle end Distance.

  Accordingly, in the imaging apparatus, the zooming effect of the second lens group to the fourth lens group is increased, and the most image side surface of the second lens group and the most object side of the third lens group at the telephoto end. The distance on the optical axis from the surface is optimized.

  The zoom lens and the imaging apparatus according to the present technology are small in size and have good optical performance over the entire zoom range, but can achieve a wide angle and a high magnification.

  The best mode for carrying out the zoom lens and the imaging apparatus of the present technology will be described below.

[Configuration of zoom lens]
The zoom lens according to the present technology includes a first lens group having a positive 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 positive refractive power. A fifth lens group having a positive refractive power is arranged in order from the object side to the image side.

  The zoom lens of the present technology moves to the object side so that the first lens group moves away from the second lens group during zooming from the wide-angle end to the telephoto end, and the third lens group approaches the second lens group. The fourth lens group moves toward the object side so that the fourth lens group approaches the third lens group.

  With such a configuration of the zoom lens, the zooming effect of the fourth lens group can be maximized from the second lens group that greatly contributes to the zooming effect of the optical system during zooming. In addition, the overall length of the optical system can be shortened and the size can be reduced.

Furthermore, the zoom lens according to the present technology satisfies the following conditional expression (1).
(1) 4.5 <100 × D (T, 2-3) / fW <15
However,
D (T, 2-3): Distance on the optical axis between the most image side surface of the second lens group and the most object side surface of the third lens group at the telephoto end fW: focal point of all optical systems at the wide angle end Distance.

  Conditional expression (1) is an expression that defines the distance between the second lens group and the third lens group at the telephoto end.

  If the upper limit of conditional expression (1) is exceeded, it becomes difficult to lengthen the movement strokes of the second lens group, the third lens group, and the fourth lens group during zooming. Cannot be obtained, or the optical system becomes large in order to obtain a zooming effect.

  On the other hand, if the lower limit of conditional expression (1) is not reached, adjacent lens groups are too close at the telephoto end, so that they are located next to each other when vibration or impact occurs when the imaging apparatus is used or carried. There is a risk of lens contact.

  Therefore, when the zoom lens satisfies the conditional expression (1), the distance on the optical axis between the most image side surface of the second lens unit and the most object side surface of the third lens unit at the telephoto end is optimized. In addition, it is possible to secure a sufficient zooming effect to achieve a wide angle, high magnification, and miniaturization, and to prevent contact between lenses.

  Conditional expression (1) is more preferably in a range greater than 8.5 and less than 10.5.

  By setting the range of conditional expression (1) to such a range, further miniaturization, wide angle and high magnification can be achieved.

In the zoom lens according to the embodiment of the present technology, the third lens group includes at least two lenses, and the third lens group includes at least one air gap formed between the lenses. It is desirable to satisfy conditional expression (2).
(2) 2.0 <d (3, air) / D (T, 2-3)
However,
d (3, air): The air interval that is the largest in the optical axis direction among the air intervals existing in the third lens group.

  Conditional expression (2) is an expression that defines the size of the air gap existing in the third lens group.

  If the lower limit of conditional expression (2) is not reached, the refractive powers of the lenses (lens groups) located opposite to each other with the air gap of the third lens group will be too strong, so that good correction of spherical aberration and coma aberration can be achieved. It becomes difficult. In addition, since the sensitivity of error between the lenses (lens groups) located opposite to each other with the air gap of the third lens group becomes too high, coma aberration, chromatic aberration, and field curvature due to error decentration after production occur. It becomes easy to do, and the image quality deteriorates.

  Accordingly, when the zoom lens satisfies the conditional expression (2), the refractive powers of the lenses (lens groups) positioned opposite to each other with the air gap interposed therebetween are optimized, and the spherical aberration and the coma aberration are favorably corrected. In addition, the error sensitivity can be reduced, and coma, chromatic aberration, and field curvature can be favorably corrected, and image quality can be improved.

  In conditional expression (2), the upper limit is 10 and the range is preferably smaller than 10.

  If the upper limit of conditional expression (2) is exceeded, the thickness of the third lens group becomes too large, which increases the overall length of the zoom lens. In particular, the lens is retracted when not in use (non-shooting) and stored well. In a so-called collapsible zoom lens designed to improve the performance, it is impossible to reduce the thickness of the zoom lens when it is stored. Accordingly, by making conditional expression (2) smaller than 10, it is possible to reduce the size of the retractable zoom lens.

  In addition, it is more preferable that conditional expression (2) is in a range greater than 2.2 and less than 5.0.

  By setting the range of conditional expression (2) to such a range, each aberration can be corrected more satisfactorily, and the image quality can be further improved.

  In the zoom lens according to the embodiment of the present technology, the third lens group includes at least two lenses, and the third lens group includes at least one air gap formed between the lenses. It is desirable to arrange a shutter mechanism having a function of shielding light rays in the air interval of the lens group.

  Thus, by arranging the shutter mechanism at the air interval of the third lens group, it is possible to shorten the optical total length by effectively using the space.

  Further, as compared with the case where the shutter mechanism is disposed between the lens groups, it is easy to lengthen the movement stroke of the lens group during zooming, and both high magnification and miniaturization can be achieved.

  Furthermore, in the zoom lens, as described above, the shutter mechanism is arranged at the air interval of the third lens group, and the conditional expression (1) is satisfied, so that the second lens group and the third lens group at the telephoto end. It is possible to reduce the distance between the lens groups, and it is possible to further increase the magnification and reduce the size.

  In the zoom lens according to the embodiment of the present technology, the third lens group includes at least two lenses, and the third lens group includes at least one air gap formed between the lenses. The object-side surface of the lens disposed closest to the object side of the lens group is formed in a convex shape, and the vertex of the object-side surface of the lens disposed closest to the object side of the third lens group and the most of the third lens group It is desirable to arrange an F-number determining member that determines an F-number light beam in an air gap existing between the image-side apex of the lens disposed on the image side. For example, an aperture stop is used as the F-number determining member.

  Thus, by arranging the F-number determining member at the air interval of the third lens group, it is possible to shorten the optical total length by effectively utilizing the space.

  Further, as compared with the case where the F-number determining member is arranged between the lens groups, it is easy to lengthen the movement stroke of the lens group during zooming, and both high magnification and miniaturization can be achieved.

  Furthermore, in the zoom lens, as described above, the F-number determining member is disposed in the air space of the third lens group, and the above conditional expression (1) is satisfied. It is possible to reduce the distance between the third lens groups, and it is possible to further increase the magnification and reduce the size.

In the zoom lens according to the embodiment of the present technology, it is preferable that the following conditional expression (3) is satisfied.
(3) 5.0 <100 × D (T, 3-4) / fW <20
However,
D (T, 3-4): The distance on the optical axis between the most image side surface of the third lens group and the most object side surface of the fourth lens group.

  Conditional expression (3) is an expression that defines the distance between the third lens group and the fourth lens group at the telephoto end.

  If the upper limit of conditional expression (3) is exceeded, it becomes difficult to lengthen the movement strokes of the second lens group, the third lens group, and the fourth lens group during zooming, so that a sufficient zooming effect is obtained. In other words, the optical system becomes large in order to obtain a zooming effect.

  On the other hand, if the lower limit of conditional expression (3) is not reached, adjacent lens groups are too close at the telephoto end, so that they are located next to each other when vibrations or impacts occur when the imaging apparatus is used or carried. There is a risk of lens contact.

  Therefore, when the zoom lens satisfies the conditional expression (3), the distance on the optical axis between the most image side surface of the second lens unit and the most object side surface of the third lens unit at the telephoto end is optimized. In addition, it is possible to secure a sufficient zooming effect to achieve high magnification and miniaturization and to prevent contact between lenses.

  Further, it is more desirable that the zoom lens satisfies the conditional expression (1) and further satisfies the conditional expression (3), and the zoom lens satisfies the conditional expression (1) and the conditional expression (3). It is possible to further increase the magnification and reduce the size.

  Furthermore, in the zoom lens, as described above, the shutter mechanism and the F-number determining member are arranged in the air interval of the third lens group, and the conditional expression (3) is satisfied, so that the third lens group at the telephoto end. And the distance between the fourth lens group can be reduced, and further magnification and miniaturization can be achieved.

  Conditional expression (3) is more preferably in a range greater than 10.0 and less than 15.5.

  By setting the range of conditional expression (3) to such a range, it is possible to further increase the magnification and reduce the size.

  In the zoom lens according to an embodiment of the present technology, the third lens group is configured by three lenses of a positive lens, a positive lens, and a negative lens arranged in order from the object side to the image side. desirable.

  By configuring the third lens group in this way, it is possible to bring the principal point position on the image side of the third lens group as close as possible to the object side, so that the third lens group is particularly small in the radial direction. It becomes easy to change. In addition, since the principal point position on the image side of the third lens group can be brought as close as possible to the second lens group at the telephoto end, it is easy to increase the zooming effect.

  In the third lens group, it is preferable that a cemented lens is configured by a positive lens and a negative lens arranged on the image side, and the cemented lens is configured by a positive lens and a negative lens so that the position of each lens is manufactured. It is possible to reduce the assembly error in as much as possible. Further, a positive lens and a negative lens arranged on the image side in the third lens group constitute a cemented lens, thereby ensuring good assemblability when a shutter mechanism or an F-number determining member is arranged in the third lens group. be able to.

In a zoom lens according to an embodiment of the present technology, it is preferable that the following conditional expression (4) is satisfied.
(4) 2.5 <f3 / fW <4.0
However,
f3: The focal length of the third lens group.

  Conditional expression (4) defines the focal length of the third lens group.

  If the upper limit of conditional expression (4) is exceeded, the refractive power of the third lens group becomes too weak, so that the zooming function is insufficient and the optical system becomes large.

  On the other hand, if the lower limit of conditional expression (4) is not reached, the refractive power of the third lens group becomes too strong, so that aberration correction in the third lens group becomes difficult and image quality deteriorates.

  Therefore, when the zoom lens satisfies the conditional expression (4), the refractive power of the third lens group is optimized, a favorable zooming function is ensured, and the optical system can be downsized. Good aberration correction is performed in the lens group, and image quality can be improved.

  Conditional expression (4) is more preferably in a range greater than 2.8 and less than 3.8.

  By setting the range of conditional expression (4) to such a range, it is possible to further reduce the size and improve the image quality.

  In the zoom lens according to an embodiment of the present technology, it is desirable that the second lens group includes three lenses, a negative lens, a negative lens, and a positive lens, which are sequentially arranged from the object side to the image side. .

  By adopting such a configuration for the second lens group, the principal point position on the image side of the second lens group can be as close as possible to the object side while ensuring sufficient refractive power for zooming. Therefore, in particular, the entrance pupil position at the wide-angle end can be easily brought closer to the object side, and it is easy to realize downsizing of the lens positioned closest to the object side in the optical system.

In the zoom lens according to the embodiment of the present technology, it is preferable that the following conditional expression (5) is satisfied.
(5) 4.2 <[D (W, 2-4) -D (T, 2-4)] / fW <5.6
However,
D (W, 2-4): Distance on the optical axis between the most object side surface of the second lens group and the most image side surface of the fourth lens group at the wide angle end D (T, 2-4): wide angle The distance on the optical axis between the most object side surface of the second lens group and the most image side surface of the fourth lens group at the end.

  Conditional expression (5) is an expression that defines the distance between the second lens group and the fourth lens group during zooming.

  If the upper limit of conditional expression (5) is exceeded, it will be difficult to lengthen the movement strokes of the second lens group, the third lens group, and the fourth lens group during zooming, so that a sufficient zooming effect is obtained. In other words, the optical system becomes large in order to obtain a zooming effect.

  On the other hand, if the lower limit of conditional expression (5) is not reached, adjacent lens groups are too close at the telephoto end, so that they are located next to each other when vibrations or impacts occur when the imaging apparatus is used or carried. There is a risk of lens contact.

  Therefore, when the zoom lens satisfies the conditional expression (5), the distance on the optical axis between the most image side surface of the second lens unit and the most object side surface of the third lens unit at the telephoto end is optimized. In addition, it is possible to secure a sufficient zooming effect to achieve high magnification and miniaturization and to prevent contact between lenses.

  Further, it is more desirable that the zoom lens satisfies the conditional expression (1) and further satisfies the conditional expression (5). When the zoom lens satisfies the conditional expression (1) and the conditional expression (5), It is possible to further increase the magnification and reduce the size.

  Further, it is more desirable that the zoom lens satisfies the conditional expression (1) and the conditional expression (3), and further satisfies the conditional expression (5). ) And conditional expression (5) are satisfied, it is possible to further increase the magnification and reduce the size.

  Furthermore, in the zoom lens, as described above, the shutter lens and the F-number determining member are arranged at the air interval of the third lens group, and the conditional expression (5) is satisfied, so that the second lens is formed at the telephoto end. It becomes possible to reduce the distance from the group to the fourth lens group, and it is possible to further increase the magnification and size.

  Conditional expression (5) is more preferably in a range greater than 4.5 and less than 5.3.

  By setting the range of conditional expression (5) to such a range, it is possible to further increase the magnification and reduce the size.

[Numerical example of zoom lens]
Hereinafter, specific embodiments of the zoom lens according to the present technology and numerical examples in which specific numerical values are applied to the embodiments will be described with reference to the drawings and tables.

  The meanings of symbols shown in the following tables and explanations are as shown below.

  “Si” is the surface number of the i-th surface counted from the object side to the image side, “ri” is the paraxial radius of curvature of the i-th surface, and “di” is the i-th surface and the (i + 1) -th surface. Axis upper surface spacing between surfaces (lens center thickness or air spacing), “ni” is the refractive index at the d-line (λ = 587.6 nm) of the lens starting from the i-th surface, and “νi” is the first The Abbe number in the d line of a lens or the like starting from the i-th surface is shown.

  “ASP” for “si” indicates that the surface is aspherical, and “INFINITY” for “ri” indicates that the surface is flat.

  “F” indicates a focal length, “Fno” indicates an F number, and “ω” indicates a half angle of view.

  “K” indicates a conic constant (conic constant), and “A”, “B”, “C”, and “D” indicate fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, respectively.

  In each table showing the following aspheric coefficients, “E−n” represents an exponential expression with a base of 10, that is, “10 to the negative n”, for example, “0.12345E-05”. Represents “0.12345 × (10 to the fifth power)”.

  Some zoom lenses used in the embodiments have an aspheric lens surface. In the aspherical shape, “x” is the distance (sag amount) in the optical axis direction from the apex of the lens surface, “y” is the height (image height) in the direction perpendicular to the optical axis direction, and “c” is the lens surface. Paraxial curvature at the apex (reciprocal of radius of curvature), “K” for conic constant (conic constant), “A”, “B”, “C”, “D” for 4th, 6th, 8th, 10th, respectively The following aspheric coefficient is defined by the following formula 1.

  FIGS. 1, 4, 7, and 10 show the lens configurations of the zoom lenses 1 to 4 in the first to fourth embodiments of the zoom lens according to the present technology, respectively.

  In each of these drawings, the arrow indicates the direction of movement during zooming.

<First Embodiment>
FIG. 1 shows a lens configuration of the zoom lens 1 according to the first embodiment of the present technology.

  The zoom lens 1 has a first lens group GR1 having a positive refractive power, a second lens group GR2 having a negative refractive power, a third lens group GR3 having a positive refractive power, and a positive refractive power. The fourth lens group GR4 and the fifth lens group GR5 having positive refractive power are arranged in order from the object side to the image side.

  The zoom lens 1 has a zoom magnification of 17.9 times.

  The first lens group GR1 includes a cemented lens formed by cementing a meniscus negative lens G1 having a convex surface facing the object side and a biconvex positive lens G2, and a meniscus positive lens having a convex surface facing the object side. G3 is arranged in order from the object side to the image side.

  The second lens group GR2 includes, from the object side, a meniscus negative lens G4 having a convex surface facing the object side, a biconcave negative lens G5, and a meniscus positive lens G6 having a convex surface facing the object side. They are arranged in order to the side.

  The third lens group GR3 includes a cemented lens formed by cementing a biconvex positive lens G7, a biconvex positive lens G8 positioned on the object side, and a biconcave negative lens G9 positioned on the image side. Are arranged in order from the object side to the image side.

  An air space is formed between the positive lens G7 and the positive lens G8 of the third lens group GR3, and the shutter mechanism SM is disposed at this air space.

  The fourth lens group GR4 includes a cemented lens formed by cementing a biconvex positive lens G10 positioned on the object side and a meniscus negative lens G11 positioned on the image side and having a concave surface facing the object side. It is configured.

  The fifth lens group GR5 includes a cemented lens in which a biconvex positive lens G12 positioned on the object side and a biconcave negative lens G13 positioned on the image side are cemented.

  A cover glass CG is disposed between the fifth lens group GR5 and the image plane IMG. Various filters such as an infrared cut filter may be disposed between the image plane IMG and the cover glass CG, and the cover glass CG is configured to have the same function as the infrared cut filter. Is also possible.

  The aperture stop STO functions as an F-number determining member that determines an F-number light beam, is disposed in the vicinity of the third lens group GR3 on the object side, and moves integrally with the third lens group GR3. A part of the positive lens G7 is inserted into the aperture of the aperture stop STO from the image side.

  Table 1 shows lens data of Numerical Example 1 in which specific numerical values are applied to the zoom lens 1 according to the first embodiment.

  In zoom lens 1, upon zooming between the wide-angle end state and the telephoto end state, the surface distance d5 between the first lens group GR1 and the second lens group GR2, and between the second lens group GR2 and the third lens group GR3. Surface distance d11, surface distance d18 between the third lens group GR3 and the fourth lens group GR4, surface distance d21 between the fourth lens group GR4 and the fifth lens group GR5, and the fifth lens group GR5 and the cover glass CG. The inter-surface distance d24 changes.

  Table 2 shows variable intervals in the wide angle end state, the intermediate focal length state, and the telephoto end state of Numerical Example 1 together with the F number Fno and the half angle of view ω.

  In the zoom lens 1, both surfaces (sixth surface, seventh surface) of the negative lens G4 of the second lens group GR2, both surfaces (tenth surface, eleventh surface) of the positive lens G6, and the positive lens G8 of the third lens group GR3. The object side surface (16th surface) and the object side surface (22nd surface) of the positive lens G12 of the fifth lens group GR5 are aspheric. Table 3 shows the fourth, sixth, eighth and tenth aspherical coefficients A, B, C and D of the aspherical surface in Numerical Example 1 together with the conic constant K.

  2 and 3 show various aberration diagrams in the infinitely focused state of Numerical Example 1, FIG. 2 shows various aberration diagrams in the wide-angle end state, and FIG. 3 shows the various aberration diagrams in the telephoto end state.

  2 and 3, the spherical aberration diagram shows the value at the d-line (wavelength 587.6 nm) with a solid line, the broken line shows the value at the g-line (wavelength 435.8 nm), and the astigmatism diagram shows a sagittal image with a solid line. The value in the plane is shown, and the value in the meridional image plane is shown by a dotted line.

  From the aberration diagrams, it is clear that Numerical Example 1 has excellent image forming performance with various aberrations corrected well.

<Second Embodiment>
FIG. 4 shows a lens configuration of the zoom lens 2 according to the second embodiment of the present technology.

  The zoom lens 2 has a first lens group GR1 having a positive refractive power, a second lens group GR2 having a negative refractive power, a third lens group GR3 having a positive refractive power, and a positive refractive power. The fourth lens group GR4 and the fifth lens group GR5 having positive refractive power are arranged in order from the object side to the image side.

  The zoom lens 2 has a zoom magnification of 17.9 times.

  The first lens group GR1 includes a cemented lens formed by cementing a meniscus negative lens G1 having a convex surface facing the object side and a biconvex positive lens G2, and a meniscus positive lens having a convex surface facing the object side. G3 is arranged in order from the object side to the image side.

  The second lens group GR2 includes, from the object side, a meniscus negative lens G4 having a convex surface facing the object side, a biconcave negative lens G5, and a meniscus positive lens G6 having a convex surface facing the object side. They are arranged in order to the side.

  The third lens group GR3 includes a cemented lens formed by cementing a biconvex positive lens G7, a biconvex positive lens G8 positioned on the object side, and a biconcave negative lens G9 positioned on the image side. Are arranged in order from the object side to the image side.

  An air space is formed between the positive lens G7 and the positive lens G8 of the third lens group GR3, and the shutter mechanism SM is disposed at this air space.

  The fourth lens group GR4 includes a cemented lens formed by cementing a biconvex positive lens G10 positioned on the object side and a meniscus negative lens G11 positioned on the image side and having a concave surface facing the object side. It is configured.

  The fifth lens group GR5 includes a cemented lens in which a biconvex positive lens G12 positioned on the object side and a biconcave negative lens G13 positioned on the image side are cemented.

  A cover glass CG is disposed between the fifth lens group GR5 and the image plane IMG. Various filters such as an infrared cut filter may be disposed between the image plane IMG and the cover glass CG, and the cover glass CG is configured to have the same function as the infrared cut filter. Is also possible.

  The aperture stop STO functions as an F-number determining member that determines an F-number light beam, is disposed between the positive lens G7 and the positive lens G8 of the third lens group GR3, and moves integrally with the third lens group GR3. The aperture stop STO is formed integrally with the shutter mechanism SM, and a part of the shutter mechanism SM is provided as the aperture stop STO.

  Table 4 shows lens data of Numerical Example 2 in which specific numerical values are applied to the zoom lens 2 according to the second embodiment.

  In the zoom lens 2, upon zooming between the wide-angle end state and the telephoto end state, the surface distance d5 between the first lens group GR1 and the second lens group GR2, and between the second lens group GR2 and the third lens group GR3. Surface distance d11, surface distance d17 between the third lens group GR3 and the fourth lens group GR4, surface distance d20 between the fourth lens group GR4 and the fifth lens group GR5, and the fifth lens group GR5 and the cover glass CG. The inter-surface distance d23 changes.

  Table 5 shows variable intervals in the wide-angle end state, the intermediate focal length state, and the telephoto end state of Numerical Example 2 together with the F number Fno and the half angle of view ω.

  In the zoom lens 2, both surfaces (sixth surface, seventh surface) of the negative lens G4 of the second lens group GR2, both surfaces (tenth surface, eleventh surface) of the positive lens G6, and the positive lens G8 of the third lens group GR3. The object side surface (fifteenth surface) and the object side surface (21st surface) of the positive lens G12 of the fifth lens group GR5 are aspheric. Table 6 shows the fourth-order, sixth-order, eighth-order, and tenth-order aspheric coefficients A, B, C, and D together with the conic constant K in Numerical Example 2.

  FIGS. 5 and 6 show various aberration diagrams in the infinite focus state in Numerical Example 2, FIG. 5 shows various aberration diagrams in the wide-angle end state, and FIG. 6 shows the various aberration diagrams in the telephoto end state.

  5 and 6, the spherical aberration diagram shows the value at the d-line (wavelength 587.6 nm) with a solid line, the broken line shows the value at the g-line (wavelength 435.8 nm), and the astigmatism diagram shows a sagittal image with a solid line. The value in the plane is shown, and the value in the meridional image plane is shown by a dotted line.

  From each aberration diagram, it is clear that Numerical Example 2 has excellent imaging performance with various aberrations corrected well.

<Third Embodiment>
FIG. 7 shows a lens configuration of the zoom lens 3 according to the third embodiment of the present technology.

  The zoom lens 3 has a first lens group GR1 having a positive refractive power, a second lens group GR2 having a negative refractive power, a third lens group GR3 having a positive refractive power, and a positive refractive power. The fourth lens group GR4 and the fifth lens group GR5 having positive refractive power are arranged in order from the object side to the image side.

  The zoom lens 3 has a zoom magnification of 17.8 times.

  The first lens group GR1 includes a cemented lens formed by cementing a meniscus negative lens G1 having a convex surface facing the object side and a biconvex positive lens G2, and a meniscus positive lens having a convex surface facing the object side. G3 is arranged in order from the object side to the image side.

  The second lens group GR2 includes, from the object side, a meniscus negative lens G4 having a convex surface facing the object side, a biconcave negative lens G5, and a meniscus positive lens G6 having a convex surface facing the object side. They are arranged in order to the side.

  The third lens group GR3 includes a cemented lens formed by cementing a biconvex positive lens G7, a biconvex positive lens G8 positioned on the object side, and a biconcave negative lens G9 positioned on the image side. Are arranged in order from the object side to the image side.

  An air space is formed between the positive lens G7 and the positive lens G8 of the third lens group GR3, and the shutter mechanism SM is disposed at this air space.

  The fourth lens group GR4 is configured by arranging a biconvex positive lens G10.

  The fifth lens group GR5 includes a cemented lens in which a biconvex positive lens G11 positioned on the object side and a biconcave negative lens G12 positioned on the image side are cemented.

  A cover glass CG is disposed between the fifth lens group GR5 and the image plane IMG. Various filters such as an infrared cut filter may be disposed between the image plane IMG and the cover glass CG, and the cover glass CG is configured to have the same function as the infrared cut filter. Is also possible.

  The aperture stop STO functions as an F-number determining member that determines an F-number light beam, is disposed in the vicinity of the third lens group GR3 on the object side, and moves integrally with the third lens group GR3. A part of the positive lens G7 is inserted into the aperture of the aperture stop STO from the image side.

  Table 7 shows lens data of Numerical Example 3 in which specific numerical values are applied to the zoom lens 3 according to the third embodiment.

  In the zoom lens 3, upon zooming between the wide-angle end state and the telephoto end state, the surface distance d5 between the first lens group GR1 and the second lens group GR2, and between the second lens group GR2 and the third lens group GR3. Surface distance d11, surface distance d18 between the third lens group GR3 and the fourth lens group GR4, surface distance d20 between the fourth lens group GR4 and the fifth lens group GR5, and the fifth lens group GR5 and the cover glass CG. The inter-surface distance d23 changes.

  Table 8 shows variable intervals in the wide-angle end state, the intermediate focal length state, and the telephoto end state of Numerical Example 3 together with the F number Fno and the half angle of view ω.

  In the zoom lens 3, both surfaces (sixth surface, seventh surface) of the negative lens G4 of the second lens group GR2, both surfaces (tenth surface, eleventh surface) of the positive lens G6, and the positive lens G8 of the third lens group GR3. The object side surface (16th surface) and the object side surface (21st surface) of the positive lens G11 of the fifth lens group GR5 are aspherical. Table 9 shows fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients A, B, C, and D together with the conic constant K in Numerical Example 3.

  8 and 9 show various aberration diagrams in the infinitely focused state in Numerical Example 3, FIG. 8 shows various aberration diagrams in the wide-angle end state, and FIG. 9 shows the various aberration diagrams in the telephoto end state.

  8 and 9, the spherical aberration diagram shows the value at the d-line (wavelength 587.6 nm) with a solid line, the broken line shows the value at the g-line (wavelength 435.8 nm), and the astigmatism diagram shows a sagittal image with a solid line. The value in the plane is shown, and the value in the meridional image plane is shown by a dotted line.

  From each aberration diagram, it is clear that Numerical Example 3 has excellent imaging performance with various aberrations corrected well.

<Fourth embodiment>
FIG. 10 illustrates a lens configuration of the zoom lens 4 according to the fourth embodiment of the present technology.

  The zoom lens 4 has a first lens group GR1 having a positive refractive power, a second lens group GR2 having a negative refractive power, a third lens group GR3 having a positive refractive power, and a positive refractive power. The fourth lens group GR4 and the fifth lens group GR5 having positive refractive power are arranged in order from the object side to the image side.

  The zoom lens 4 has a zoom magnification of 17.9 times.

  The first lens group GR1 includes a cemented lens formed by cementing a meniscus negative lens G1 having a convex surface facing the object side and a biconvex positive lens G2, and a meniscus positive lens having a convex surface facing the object side. G3 is arranged in order from the object side to the image side.

  The second lens group GR2 includes, from the object side, a meniscus negative lens G4 having a convex surface facing the object side, a biconcave negative lens G5, and a meniscus positive lens G6 having a convex surface facing the object side. They are arranged in order to the side.

  The third lens group GR3 includes a cemented lens formed by cementing a biconvex positive lens G7, a biconvex positive lens G8 positioned on the object side, and a biconcave negative lens G9 positioned on the image side. Are arranged in order from the object side to the image side.

  An air space is formed between the positive lens G7 and the positive lens G8 of the third lens group GR3, and the shutter mechanism SM is disposed at this air space.

  The fourth lens group GR4 is configured by arranging a biconvex positive lens G10.

  The fifth lens group GR5 includes a cemented lens in which a biconvex positive lens G11 positioned on the object side and a biconcave negative lens G12 positioned on the image side are cemented.

  A cover glass CG is disposed between the fifth lens group GR5 and the image plane IMG. Various filters such as an infrared cut filter may be disposed between the image plane IMG and the cover glass CG, and the cover glass CG is configured to have the same function as the infrared cut filter. Is also possible.

  The aperture stop STO functions as an F-number determining member that determines an F-number light beam, is disposed between the positive lens G7 and the positive lens G8 of the third lens group GR3, and moves integrally with the third lens group GR3. The aperture stop STO is formed integrally with the shutter mechanism SM, and a part of the shutter mechanism SM is provided as the aperture stop STO.

  Table 10 shows lens data of a numerical example 4 in which specific numerical values are applied to the zoom lens 4 according to the fourth embodiment.

  When the zoom lens 4 is zoomed between the wide-angle end state and the telephoto end state, the surface distance d5 between the first lens group GR1 and the second lens group GR2, and between the second lens group GR2 and the third lens group GR3. Surface distance d11, surface distance d17 between the third lens group GR3 and the fourth lens group GR4, surface distance d19 between the fourth lens group GR4 and the fifth lens group GR5, and the fifth lens group GR5 and the cover glass CG. The surface interval d22 between the two changes.

  Table 11 shows variable intervals in the wide-angle end state, the intermediate focal length state, and the telephoto end state of Numerical Example 4 together with the F number Fno and the half angle of view ω.

  In the zoom lens 4, both surfaces (sixth surface, seventh surface) of the negative lens G4 of the second lens group GR2, both surfaces (tenth surface, eleventh surface) of the positive lens G6, and the positive lens G8 of the third lens group GR3. The object side surface (fifteenth surface) and the object side surface (20th surface) of the positive lens G11 of the fifth lens group GR5 are aspheric. Table 12 shows the fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients A, B, C, and D together with the conic constant K in Numerical Example 4.

  11 and 12 show various aberration diagrams in the infinite focus state in Numerical Example 4, FIG. 11 shows various aberration diagrams in the wide-angle end state, and FIG. 12 shows the aberration diagrams in the telephoto end state.

  In FIGS. 11 and 12, the spherical aberration diagram shows the value at the d-line (wavelength 587.6 nm) with a solid line, the broken line shows the value at the g-line (wavelength 435.8 nm), and the astigmatism diagram shows a sagittal image with a solid line. The value in the plane is shown, and the value in the meridional image plane is shown by a dotted line.

  From each aberration diagram, it is clear that Numerical Example 4 has excellent imaging performance with various aberrations corrected well.

[Each value of conditional expression of zoom lens]
Hereinafter, each value of the conditional expression of the zoom lens according to the present technology will be described.

  Table 13 shows values of the conditional expressions (1) to (5) in the zoom lenses 1 to 4.

  As is clear from Table 13, the zoom lenses 1 to 4 satisfy the conditional expressions (1) to (5).

[Operation during zooming]
In the zoom lens according to the present technology, the shutter mechanism or the shutter mechanism and the F-number determining member are arranged in the air gap formed in the third lens group so as to effectively use the space. By effectively utilizing this space, the shutter mechanism or the F-number determining member is not disposed between the lens groups, and accordingly, the distance between the second lens group and the third lens group can be reduced at the telephoto end and the third lens. The distance between the group and the fourth lens group can be reduced.

  Therefore, the moving stroke from the second lens group to the fourth lens group during zooming can be lengthened, and downsizing can be achieved by increasing the magnification, widening the angle, and shortening the optical total length.

  FIG. 13 shows the operating position of each lens group between the wide-angle end and the telephoto end of the zoom lens 1 as an example. As shown in FIG. 13, in the zoom lens 1, the second lens group and the third lens group are positioned close to each other at the telephoto end, and the third lens group and the fourth lens group are positioned close to each other. .

  Further, as described above, the zoom lens according to the present technology is configured to satisfy the conditional expression (1), and the most image side surface of the second lens unit and the most object side of the third lens unit at the telephoto end. The distance on the optical axis on the optical axis is optimized, and a sufficient zooming effect is secured to increase the magnification, widen the angle, and reduce the size, and to prevent contact between the lenses.

  Furthermore, as described above, the zoom lens according to the present technology is configured to satisfy the conditional expression (3), and the most image side surface of the second lens unit and the most object side of the third lens unit at the telephoto end. The distance on the optical axis with respect to the surface of the lens is optimized, and a sufficient zooming effect is ensured to increase the magnification and size, and to prevent contact between the lenses.

[Configuration of imaging device]
An imaging apparatus according to an embodiment of the present technology includes a zoom lens and an imaging element that converts an optical image formed by the zoom lens into an electrical signal. The zoom lens has a first lens group having a positive refractive power and a negative refractive power. A second lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power are sequentially arranged from the object side to the image side. Become.

  In the imaging device of the present technology, the zoom lens moves to the object side so that the first lens group is separated from the second lens group during zooming from the wide-angle end to the telephoto end, and the third lens group is the second lens group. The lens moves toward the object side so as to approach the lens group, and the fourth lens group moves toward the object side so as to approach the third lens group.

  With such a configuration of the zoom lens, the zooming effect of the fourth lens group can be maximized from the second lens group that greatly contributes to the zooming effect of the optical system during zooming. In addition, the overall length of the optical system can be shortened and the size can be reduced.

Furthermore, in the imaging device of the present technology, the zoom lens satisfies the following conditional expression (1).
(1) 4.5 <100 × D (T, 2-3) / fW <15
However,
D (T, 2-3): Distance on the optical axis between the most image side surface of the second lens group and the most object side surface of the third lens group at the telephoto end fW: focal point of all optical systems at the wide angle end Distance.

  Conditional expression (1) is an expression that defines the distance between the second lens group and the third lens group at the telephoto end.

  If the upper limit of conditional expression (1) is exceeded, it becomes difficult to lengthen the movement strokes of the second lens group, the third lens group, and the fourth lens group during zooming. Cannot be obtained, or the optical system becomes large in order to obtain a zooming effect.

  On the other hand, if the lower limit of conditional expression (1) is not reached, adjacent lens groups are too close at the telephoto end, so that they are located next to each other when vibration or impact occurs when the imaging apparatus is used or carried. There is a risk of lens contact.

  Therefore, when the zoom lens satisfies the conditional expression (1), the distance on the optical axis between the most image side surface of the second lens unit and the most object side surface of the third lens unit at the telephoto end is optimized. In addition, it is possible to secure a sufficient zooming effect, increase the magnification, widen the angle, and reduce the size, and prevent contact between the lenses.

  Conditional expression (1) is more preferably in a range greater than 8.5 and less than 10.5.

  By setting the range of conditional expression (1) to such a range, it is possible to further increase the magnification, widen the angle, and reduce the size.

[One Embodiment of Imaging Device]
FIG. 14 is a block diagram of a digital still camera according to an embodiment of the imaging apparatus of the present technology.

  An imaging apparatus (digital still camera) 100 performs a camera block 10 that performs an imaging function, a camera signal processing unit 20 that performs signal processing such as analog-digital conversion of a captured image signal, and recording and reproduction processing of the image signal. And an image processing unit 30. The imaging apparatus 100 also includes an LCD (Liquid Crystal Display) 40 that displays captured images and the like, an R / W (reader / writer) 50 that writes and reads image signals to and from the memory card 1000, and imaging. A central processing unit (CPU) 60 that controls the entire apparatus, an input unit 70 including various switches that are operated by a user, and a lens driving control that controls the driving of lenses arranged in the camera block 10 Part 80.

  The camera block 10 includes an optical system including a zoom lens 11 (zoom lenses 1, 2, 3, and 4 to which the present technology is applied), and an image sensor such as a CCD (Charge Coupled Device) and a CMOS (Complementary Metal-Oxide Semiconductor). 12 etc.

  The camera signal processing unit 20 performs various types of signal processing such as conversion of the output signal from the image sensor 12 into a digital signal, noise removal, image quality correction, and conversion into a luminance / color difference signal.

  The image processing unit 30 performs compression encoding / decompression decoding processing of an image signal based on a predetermined image data format, conversion processing of data specifications such as resolution, and the like.

  The LCD 40 has a function of displaying various data such as an operation state of the user input unit 70 and a photographed image.

  The R / W 50 writes the image data encoded by the image processing unit 30 to the memory card 1000 and reads the image data recorded on the memory card 1000.

  The CPU 60 functions as a control processing unit that controls each circuit block provided in the imaging apparatus 100, and controls each circuit block based on an instruction input signal or the like from the input unit 70.

  The input unit 70 includes, for example, a shutter release button for performing a shutter operation, a selection switch for selecting an operation mode, and the like, and outputs an instruction input signal corresponding to an operation by a user to the CPU 60.

  The lens drive control unit 80 controls a motor (not shown) that drives each lens of the zoom lens 11 based on a control signal from the CPU 60.

  The memory card 1000 is a semiconductor memory that can be attached to and detached from a slot connected to the R / W 50, for example.

  Hereinafter, an operation in the imaging apparatus 100 will be described.

  In a shooting standby state, under the control of the CPU 60, an image signal shot by the camera block 10 is output to the LCD 40 via the camera signal processing unit 20 and displayed as a camera through image. In addition, when an instruction input signal for zooming is input from the input unit 70, the CPU 60 outputs a control signal to the lens drive control unit 80, and a predetermined value of the zoom lens 11 is controlled based on the control of the lens drive control unit 80. The lens is moved.

  When a shutter (not shown) of the camera block 10 is operated by an instruction input signal from the input unit 70, the captured image signal is output from the camera signal processing unit 20 to the image processing unit 30 and subjected to compression encoding processing. Converted to digital data in data format. The converted data is output to the R / W 50 and written to the memory card 1000.

  In focusing, for example, when the shutter release button of the input unit 70 is half-pressed or when the shutter release button is fully pressed for recording (photographing), the lens drive control unit 80 controls the zoom lens based on a control signal from the CPU 60. This is done by moving 11 predetermined lenses.

  When reproducing the image data recorded on the memory card 1000, predetermined image data is read from the memory card 1000 by the R / W 50 according to the operation on the input unit 70, and decompressed and decoded by the image processing unit 30. After the processing is performed, the reproduction image signal is output to the LCD 40 and the reproduction image is displayed.

  In the above-described embodiment, an example in which the imaging device is applied to a digital still camera has been shown. However, the application range of the imaging device is not limited to a digital still camera, and a digital video camera and a camera are incorporated. The present invention can be widely applied as a camera unit of a digital input / output device such as a mobile phone or a PDA (Personal Digital Assistant) in which a camera is incorporated.

[Technology]
The present technology can be configured as follows.

<1> A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a positive refraction And a fifth lens group having power, which are arranged in order from the object side to the image side, and the first lens group is separated from the second lens group during zooming from the wide-angle end to the telephoto end. The third lens group moves toward the object side so as to approach the second lens group, and the fourth lens group moves toward the object side so as to approach the third lens group. A zoom lens satisfying (1).
(1) 4.5 <100 × D (T, 2-3) / fW <15
However,
D (T, 2-3): Distance on the optical axis between the most image side surface of the second lens group and the most object side surface of the third lens group at the telephoto end fW: focal point of all optical systems at the wide angle end Distance.

<2> The third lens group includes at least two lenses, and the third lens group includes at least one air gap formed between the lenses, and satisfies the following conditional expression (2): The zoom lens according to <1>.
(2) 2.0 <d (3, air) / D (T, 2-3)
However,
d (3, air): The air interval that is the largest in the optical axis direction among the air intervals existing in the third lens group.

  <3> The third lens group includes at least two lenses, and the third lens group includes at least one air gap formed between the lenses. A light beam is emitted to the air gap of the third lens group. The zoom lens according to <1> or <2>, wherein a shutter mechanism having a function of shielding light is disposed.

  <4> The third lens group includes at least two lenses, and the third lens group includes at least one air gap formed between the lenses, and is disposed on the most object side of the third lens group. The object side surface of the formed lens is formed in a convex shape, and is arranged at the apex of the object side surface of the lens arranged closest to the object side of the third lens group and the image side of the third lens group. The zoom lens according to any one of <1> to <3>, wherein an F-number determining member that determines an F-number light beam is disposed in the air space existing between the apex on the image side of the lens.

<5> The zoom lens according to any one of <1> to <4>, wherein the following conditional expression (3) is satisfied.
(3) 5.0 <100 × D (T, 3-4) / fW <20
However,
D (T, 3-4): The distance on the optical axis between the most image side surface of the third lens group and the most object side surface of the fourth lens group.

  <6> Any one of <1> to <6>, wherein the third lens group includes three lenses, a positive lens, a positive lens, and a negative lens, which are sequentially arranged from the object side to the image side. The described zoom lens.

<7> The zoom lens according to any one of <1> to <6>, wherein the following conditional expression (4) is satisfied.
(4) 2.5 <f3 / fW <4.0
However,
f3: The focal length of the third lens group.

  <8> Any one of the items <1> to <7>, wherein the second lens group includes three lenses of a negative lens, a negative lens, and a positive lens arranged in order from the object side to the image side. The described zoom lens.

<9> The zoom lens according to any one of <1> to <8>, wherein the following conditional expression (5) is satisfied.
(5) 4.2 <[D (W, 2-4) -D (T, 2-4)] / fW <5.6
However,
D (W, 2-4): Distance on the optical axis between the most object side surface of the second lens group and the most image side surface of the fourth lens group at the wide angle end D (T, 2-4): wide angle The distance on the optical axis between the most object side surface of the second lens group and the most image side surface of the fourth lens group at the end.

<10> A zoom lens and an image sensor that converts an optical image formed by the zoom lens into an electrical signal, wherein the zoom lens has a first lens group having a positive refractive power and a negative refractive power. A second lens group, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power are sequentially arranged from the object side to the image side. During zooming from the wide-angle end to the telephoto end, the object moves so that the first lens group moves toward the object side away from the second lens group, and the third lens group approaches the second lens group. An image pickup apparatus that moves toward the object side, moves toward the object side so that the fourth lens group approaches the third lens group, and satisfies the following conditional expression (1):
(1) 4.5 <100 × D (T, 2-3) / fW <15
However,
D (T, 2-3): Distance on the optical axis between the most image side surface of the second lens group and the most object side surface of the third lens group at the telephoto end fW: focal point of all optical systems at the wide angle end Distance.

  The shapes and numerical values of the respective parts shown in the above-described embodiments are merely examples of specific embodiments for carrying out the present technology, and the technical scope of the present technology is limitedly interpreted by these. There should not be.

It is a figure which shows the lens structure of 1st Embodiment of a zoom lens. FIG. 3 is an aberration diagram of a numerical example in which specific numerical values are applied to the first embodiment, and FIG. 3 is a diagram illustrating spherical aberration, astigmatism, and distortion in the wide-angle end state. It is a figure which shows the spherical aberration, astigmatism, and distortion aberration in a telephoto end state. It is a figure which shows the lens structure of 2nd Embodiment of a zoom lens. FIG. 6 shows aberration diagrams of numerical examples in which specific numerical values are applied to the second embodiment, and FIG. 6 is a diagram showing spherical aberration, astigmatism, and distortion in the wide-angle end state. It is a figure which shows the spherical aberration, astigmatism, and distortion aberration in a telephoto end state. It is a figure which shows the lens structure of 3rd Embodiment of a zoom lens. FIG. 9 shows aberration diagrams of numerical examples in which specific numerical values are applied to the third embodiment, and FIG. 9 is a diagram showing spherical aberration, astigmatism, and distortion aberration in the wide-angle end state. It is a figure which shows the spherical aberration, astigmatism, and distortion aberration in a telephoto end state. It is a figure which shows the lens structure of 4th Embodiment of a zoom lens. FIG. 12 shows aberration diagrams of numerical examples obtained by applying specific numerical values to the fourth embodiment, and FIG. 12 is a diagram showing spherical aberration, astigmatism, and distortion aberration in the wide-angle end state. It is a figure which shows the spherical aberration, astigmatism, and distortion aberration in a telephoto end state. It is a figure which shows operation | movement at the time of zooming. It is a block diagram which shows an example of an imaging device.

  DESCRIPTION OF SYMBOLS 1 ... Zoom lens, 2 ... Zoom lens, 3 ... Zoom lens, 4 ... Zoom lens, GR1 ... 1st lens group, GR2 ... 2nd lens group, GR3 ... 3rd lens group, GR4 ... 4th lens group, GR5 ... 5th lens group, 100 ... imaging device, 11 ... zoom lens, 12 ... imaging device

Claims (10)

A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a positive refractive power The fifth lens group is arranged in order from the object side to the image side,
During zooming from the wide-angle end to the telephoto end, the first lens group moves toward the object side away from the second lens group, and the third lens group moves closer to the second lens group. Moving to the object side so that the fourth lens group approaches the third lens group,
A zoom lens that satisfies the following conditional expression (1).
(1) 4.5 <100 × D (T, 2-3) / fW <15
However,
D (T, 2-3): Distance on the optical axis between the most image side surface of the second lens group and the most object side surface of the third lens group at the telephoto end fW: focal point of all optical systems at the wide angle end Distance. The third lens group is composed of at least two lenses, and the third lens group has at least one air gap formed between the lenses;
The zoom lens according to claim 1, wherein the following conditional expression (2) is satisfied.
(2) 2.0 <d (3, air) / D (T, 2-3)
However,
d (3, air): The air interval that is the largest in the optical axis direction among the air intervals existing in the third lens group. The third lens group is composed of at least two lenses, and the third lens group has at least one air gap formed between the lenses;
The zoom lens according to claim 1, wherein a shutter mechanism having a function of shielding light rays is disposed in an air space of the third lens group. The third lens group is composed of at least two lenses, and the third lens group has at least one air gap formed between the lenses;
The object side surface of the lens arranged closest to the object side of the third lens group is formed into a convex shape,
The air gap existing between the vertex of the object side surface of the lens disposed closest to the object side of the third lens group and the vertex of the image side of the lens disposed closest to the image side of the third lens group. The zoom lens according to claim 1, further comprising an F-number determining member that determines an F-number luminous flux. The zoom lens according to claim 1, wherein the following conditional expression (3) is satisfied.
(3) 5.0 <100 × D (T, 3-4) / fW <20
However,
D (T, 3-4): The distance on the optical axis between the most image side surface of the third lens group and the most object side surface of the fourth lens group. The zoom lens according to claim 1, wherein the third lens group includes three lenses, a positive lens, a positive lens, and a negative lens, which are arranged in order from the object side to the image side. The zoom lens according to claim 1, wherein the following conditional expression (4) is satisfied.
(4) 2.5 <f3 / fW <4.0
However,
f3: The focal length of the third lens group. The zoom lens according to claim 1, wherein the second lens group is configured by three lenses, a negative lens, a negative lens, and a positive lens, which are arranged in order from the object side to the image side. The zoom lens according to claim 1, wherein the following conditional expression (5) is satisfied.
(5) 4.2 <[D (W, 2-4) -D (T, 2-4)] / fW <5.6
However,
D (W, 2-4): Distance on the optical axis between the most object side surface of the second lens group and the most image side surface of the fourth lens group at the wide angle end D (T, 2-4): wide angle The distance on the optical axis between the most object side surface of the second lens group and the most image side surface of the fourth lens group at the end. A zoom lens and an image sensor that converts an optical image formed by the zoom lens into an electrical signal;
The zoom lens is
A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a positive refractive power The fifth lens group is arranged in order from the object side to the image side,
During zooming from the wide-angle end to the telephoto end, the first lens group moves toward the object side away from the second lens group, and the third lens group moves closer to the second lens group. Moving to the object side so that the fourth lens group approaches the third lens group,
An imaging apparatus that satisfies the following conditional expression (1).
(1) 4.5 <100 × D (T, 2-3) / fW <15
However,
D (T, 2-3): Distance on the optical axis between the most image side surface of the second lens group and the most object side surface of the third lens group at the telephoto end fW: focal point of all optical systems at the wide angle end Distance.

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