WO2021068098A1

WO2021068098A1 - Optical apparatus, imaging apparatus and mobile equipment

Info

Publication number: WO2021068098A1
Application number: PCT/CN2019/109860
Authority: WO
Inventors: Takuya Anzawa; Izumi RYOTARO; Horidan ATSUSHI; Sekiguchi NAOKI; Atsushi Yoneyama
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2019-10-08
Filing date: 2019-10-08
Publication date: 2021-04-15
Also published as: CN114467047B; CN114467047A

Abstract

An optical apparatus (100A) is provided, the optical apparatus (100A) including: first to fourth lens groups each including one or more lenses, where the first lens group (Group 1) includes a bending optical element, where at least one lens or lens group in the second to fourth lens groups is moved for focusing, and a parameter FS related to focusing sensitivity is expressed by FS=|(1-M _f ²)(∏ _i=m ⁿ _Mi) ²|, and the parameter FS satisfies a condition: FS＜4, where M _f, indicates lateral magnification of the at least one lens or lens group and M _i (i=m,..., n) indicates lateral magnification of an i-th lens located on an image side of the at least one lens or lens group.

Description

OPTICAL APPARATUS, IMAGING APPARATUS AND MOBILE EQUIPMENT

TECHNICAL FIELD

The present disclosure relates to an optical apparatus, an imaging apparatus and mobile equipment with a camera function.

BACKGROUND

A lot of mobile equipment are equipped with a camera module providing a camera function. The camera module includes an optical apparatus and an imaging device. The optical apparatus includes a lens system including a plurality of lenses, and actuators for moving the lenses for automatic focusing and optical image stabilization. The imaging device generates image data based on light passing through the optical apparatus. For example, the imaging device may be a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor, a CCD (Charge Coupled Device) image sensor, or the like.

Recent types of mobile equipment are equipped with a high-performance camera function. The high-performance camera function may be implemented by a high-performance optical system with few aberrations and an imaging device with high resolution. The high-performance optical system includes a plurality of lenses to reduce a monochromatic aberration and a chromatic aberration. The use of such a high-performance optical system increases the size of the camera module in the direction of the optical axis, which makes it difficult to accommodate the camera module in compact mobile equipment. With regard to this problem, U.S. Patent Application Publication No. 2017/0276914A1 and U.S. Patent Application Publication No. 2017/0276912A1 have proposed methods of using a folded lens system to accommodate a camera module in compact mobile equipment.

Even with the folded lens system used, there is a limitation to the size of a camera module that can be accommodated in compact mobile equipment. Therefore, it is desirable to develop more compact and higher-performance optical systems. In particular, the moving distance of a focusing lens in a telephoto lens and a macro lens is long, and the lens system of the telephoto lens and the macro lens is long in the direction of the optical axis. As a result, the focal length of an optical system equipped in compact mobile equipment is short, or the shortest shooting distance is long.

SUMMARY

Embodiments provide an optical apparatus, an imaging apparatus and mobile equipment. For example, the mobile equipment may be a mobile phone, a smart phone, a wireless communication terminal, a tablet device, a personal computer, or the like. The imaging apparatus may be a still camera, a video camera, a movie camera, a drive recorder, a web camera or the like.

A first aspect of an embodiment provides an optical apparatus. In a first possible implementation form of the first aspect, the optical apparatus comprises: first to fourth lens groups each including one or more lenses, wherein the first lens group includes a bending optical element, wherein at least one lens or lens group in the second to fourth lens groups is used for focusing, and a parameter FS related to focusing sensitivity is expressed by Equation (1) :

and the parameter FS satisfies a condition of Equation (2) :

FS<4 ... Eq. (2) ,

where M _f indicates lateral magnification of the at least one lens or lens group and M _i (i=m, ..., n) indicates lateral magnification of an i-th lens located on an image side of the at least one lens or lens group (am-th lens is a lens firstly located on the image side of the at least one lens or lens group for focusing) .

Increasing the parameter FS related to the position sensitivity of the focusing lens can make the amount of movement of the focusing lens smaller. However, in order to increase the parameter FS, it is necessary to increase the lateral magnification of the focusing lens, and the increase in lateral magnification leads to the expansion of various aberrations. Satisfying the condition defined by the Equation (2) can minimize the amount of movement of the focusing lens within an allowable range, which can suppress various aberrations to achieve high optical performance. Accordingly, a high-performance lens with a long focal length, a high-performance lens with a short shortest shooting distance, or a high-performance lens with a long focal length and a short shortest shooting distance may be equipped in compact mobile equipment and imaging apparatus.

A second possible implementation form of the first aspect provides: the optical apparatus according to the first or second possible implementation form of the first aspect, wherein the parameter FS further satisfies a condition of Equation (2a) :

FS>0.5 ... Eq. (2a) .

Decreasing the parameter FS related to the position sensitivity of the focusing lens can make the lateral magnification of the focusing lens smaller. The decrease in lateral magnification can reduce various aberrations. The decrease in parameter FS, however, increases the amount of movement of the focusing lens. Satisfying the condition defined by the Equation (2a) can minimize the amount of movement of the focusing lens within an allowable range, which can suppress various aberrations to achieve high optical performance. Accordingly, a high-performance lens with a long focal length, a high-performance lens with a short shortest shooting distance, or a high-performance lens with a long focal length and a short shortest shooting distance may be equipped in compact mobile equipment and imaging apparatus.

A third possible implementation form of the first aspect provides: the optical apparatus according to the second possible implementation form of the first aspect, wherein the parameter FS further satisfies a condition of Equation (2b) :

0.9<FS<3.95 ... Eq. (2b) .

Satisfying the condition defined by the Equation (2b) may lead to realization of an optical apparatus having the balance between the entire length of the lens system and the optical performance in better balance.

A fourth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to third possible implementation forms of the first aspect, wherein a total lens length TTL of an entire lens system including the first to fourth lens groups satisfies a condition of Equation (3) :

TTL/F>0.7 ... Eq. (3) ,

where F indicates a focal length of the entire lens system.

When the entire length of the lens system is short as compared with the focal length, it is necessary to increase the refractive power of each lens. The increase in the refractive power of each lens expands various aberrations. Satisfying the condition defined by the Equation (3) suppresses various aberrations to provide higher optical performance.

A fifth possible implementation form of the first aspect provides: the optical apparatus according to the fourth possible implementation form of the first aspect, wherein the total lens length TTL of the entire lens system further satisfies a condition of Equation (3a) :

1.0<TTL/F<3.5 ... Eq. (3a) .

Satisfying the condition defined by the Equation (3a) may lead to realization of an optical apparatus having the balance between the entire length of the lens system and the optical performance in better balance.

A sixth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to fifth possible implementation forms of the first aspect, wherein a focal length F2 of the second lens group satisfies a condition of Equation (4) :

|F2/F|<6.0 ... Eq. (4) ,

where F indicates a focal length of the entire lens system.

When the focal length of the second lens group is extremely long as compared with the focal length of the lens system, the refractive power of the second lens group becomes smaller. The decrease in the refractive power of the second lens group reduces various aberrations in the second lens group. However, this makes the effective diameter of the second lens group larger and the entire length of the lens system longer. Satisfying the condition defined by the Equation (4) suppresses various aberrations in the second lens group to provide higher optical performance and makes the effective diameter of the second lens group smaller and the entire length of the lens system shorter.

A seventh possible implementation form of the first aspect provides: the optical apparatus according to the sixth possible implementation form of the first aspect, wherein the focal length F2 of the second lens group further satisfies a condition of Equation (4a) :

0.5<|F2/F|<5.7 ... Eq. (4a) .

Satisfying the condition defined by the Equation (4a) may lead to realization of an optical apparatus having the balance between the entire length of the lens system and the optical performance in better balance.

An eighth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to seventh possible implementation forms of the first aspect, wherein a focal length F3 of the third lens group satisfies a condition of Equation (5) :

|F3/F|<1.2 ... Eq. (5) ,

where F indicates a focal length of the entire lens system.

When the focal length of the third lens group is extremely long as compared with the focal length of the lens system, the refractive power of the third lens group becomes smaller. The decrease in the refractive power of the third lens group reduces various aberrations in the third lens group. However, this makes the effective diameter of the third lens group larger and the entire length of the lens system longer. Satisfying the condition defined by the Equation (5) suppresses various aberrations in the third lens group to provide higher optical performance and makes the effective diameter of the third lens group smaller and the entire length of the lens system shorter.

A ninth possible implementation form of the first aspect provides: the optical apparatus according to the eighth possible implementation form of the first aspect, wherein the focal length F3 of the third lens group satisfies a condition of Equation (5a) :

0.1<|F3/F|<1.1 ... Eq. (5a) .

Satisfying the condition defined by the Equation (5a) may lead to realization of an optical apparatus having the balance between the entire length of the lens system and the optical performance in better balance.

A tenth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to ninth possible implementation forms of the first aspect, wherein a focal length F4 of the fourth lens group satisfies a condition of Equation (6) :

|F4/F|<4.5 ... Eq. (6) ,

where F indicates a focal length of the entire lens system.

When the focal length of the fourth lens group is extremely long as compared with the focal length of the lens system, the refractive power of the fourth lens group becomes smaller. The decrease in the refractive power of the fourth lens group reduces various aberrations in the fourth lens group. However, this makes the effective diameter of the fourth lens group larger and the entire length of the lens system longer. Satisfying the condition defined by the Equation (6) suppresses various aberrations in the fourth lens group to provide higher optical performance and makes the effective diameter of the fourth lens group smaller and the entire length of the lens system shorter.

An eleventh possible implementation form of the first aspect provides: the optical apparatus according to the tenth possible implementation form of the first aspect, wherein the focal length F4 of the fourth lens group satisfies a condition of Equation (6a) :

0.3<|F4/F|<4.4 ... Eq. (6a) .

Satisfying the condition defined by the Equation (6a) may lead to realization of an optical apparatus having the balance between the entire length of the lens system and the optical performance in better balance.

A twelfth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to eleventh possible implementation forms of the first aspect, wherein a focal length F1 of the first lens group and a focal length F2 of the second lens group satisfy a condition of Equation (7) :

|F1/F2|<7.5 ... Eq. (7) .

Equation (7) is an equation about a synthetic focal length of the first lens group and that of the second lens group. If a value of |F1/F2| is above an upper limit, the synthetic focal length of the first lens group becomes longer, which increases a total length and effective diameter. Also, because the focal length of the second group becomes smaller, which specifically increases spherical aberration, thereby causing deterioration of optical performance. However, satisfying the condition defined by the Equation (7) may shorten the entire length of the lens system and reduce the spherical aberration of the lens system.

A thirteenth possible implementation form of the first aspect provides: the optical apparatus according to the twelfth possible implementation form of the first aspect, wherein the focal length F1 of the first lens group and the focal length F2 of the second lens group further satisfy a condition of Equation (7a) :

0.25<|F1/F2|<7.3 ... Eq. (7a) .

Satisfying the condition defined by the Equation (7a) may provide the shorter length of the lens system and higher optical performance.

A fourteenth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to thirteenth possible implementation forms of the first aspect, wherein a focal length F2 of the second lens group and a focal length F3 of the third lens group satisfy a condition of Equation (8) :

|F2/F3|<10.0 ... Eq. (8) .

Equation (8) is an equation about a synthetic focal length of the second lens group and that of the third lens group. If a value of |F2/F3| is above an upper limit, the synthetic focal length of the second lens group becomes longer, which increases a total length. Also, because the focal length of the third group becomes smaller, the focal length of aberration occurring in the third lens group becomes greater, thereby causing deterioration of optical performance. However, satisfying the condition defined by the Equation (8) may shorten the entire length of the lens system and reduce the aberration arising in the third lens group.

A fifteenth possible implementation form of the first aspect provides: the optical apparatus according to the fourteenth possible implementation form of the first aspect, wherein the focal length F2 of the second lens group and the focal length F3 of the third lens group further satisfy a condition of Equation (8a) :

0.5<|F2/F3|<9.8 ... Eq. (8a) .

Satisfying at least one of the conditions defined by the Equation (8a) can provide the shorter length of the lens system and higher optical performance.

A sixteenth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to fifteenth possible implementation forms of the first aspect, wherein Abbe's number v _f of at least one focusing lens or focusing lens group satisfies a condition of Equation (9) :

v _f>16 ... Eq. (9) .

A seventeenth possible implementation form of the first aspect provides: the optical apparatus according to the sixteenth possible implementation form of the first aspect, wherein the Abbe's number v _f of at least one focusing lens or focusing lens group further satisfies a condition of Equation (9a) :

25<v _f<58 ... Eq. (9a) .

The magnitudes of various aberrations depend on the material of the lens in addition to the refractive power of the lens. Applying a lens whose material satisfies the condition defined by the Equation (9) can effectively suppress the occurrence of chromatic aberration. Furthermore, applying a lens whose material satisfies the equation (9a) can suppress the occurrence of chromatic aberration more effectively. In addition, since the occurrence of chromatic aberration can be suppressed, high optical performance can be achieved not only in infinite distance but also in close distance. This suppression may also result in sufficient optical performance.

An eighteenth possible implementation form of the first aspect provides: the optical apparatus according to the sixteenth or seventeenth possible implementation form of the first aspect, wherein if a plurality of lenses are moved for the focusing, the Abbe's number v _f is an average of Abbe's numbers of the plurality of lenses.

A nineteenth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to seventeenth possible implementation forms of the first aspect, wherein the at least one lens or lens group which is a focusing lens or group is moved along a direction perpendicular to an optical axis of the at least one lens or lens group which is a focusing lens or group for optical image stabilization.

Moving the focusing lens in a direction perpendicular to the optical axis to achieve optical image stabilization contributes to the miniaturization of the optical apparatus.

A twentieth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to third possible implementation forms of the first aspect, wherein the first lens group includes one or more lenses located on an object side of the bending optical element.

The use of the bending optical element makes it possible to bend the optical axis, which increases the degree of freedom in implementing the optical apparatus into mobile equipment or the like. If the one or more lenses located on the object side of the bending optical element may decrease the width of a beam of light incident on the bending optical element, this contributes to the miniaturization of the bending optical element.

A twenty-first possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to twentieth possible implementation forms of the first aspect, wherein the first lens group has positive refractive power, the second lens group has positive refractive power, the third lens group has negative refractive power and the fourth lens group has positive refractive power.

A twenty-second possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to twentieth possible implementation forms of the first aspect, wherein the first lens group has positive refractive power, the second lens group has negative refractive power, the third lens group has positive refractive power and the fourth lens group has positive refractive power.

A twenty-third possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to twentieth possible implementation forms of the first aspect, wherein the first lens group has negative refractive power, the second lens group has positive refractive power, the third lens group has negative refractive power and the fourth lens group has positive refractive power.

A twenty-fourth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to twentieth possible implementation forms of the first aspect, wherein the first lens group has negative refractive power, the second lens group has positive refractive power, the third lens group has positive refractive power and the fourth lens group has negative refractive power.

A twenty-fifth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to twentieth possible implementation forms of the first aspect, wherein the first lens group has positive refractive power, the second lens group has negative refractive power, the third lens group has positive refractive power, and the fourth lens group has negative refractive power.

A twenty-sixth possible implementation form of the first aspect provides: the optical apparatus according to any one of the first to twenty-fifth possible implementation forms of the first aspect, further comprising: an actuator configured to move the at least one lens or lens group for at least one of automatic focusing and optical image stabilization.

A second aspect of an embodiment provides an imaging apparatus. In a possible implementation form of the second aspect, the imaging apparatus comprises: the optical apparatus according to any one of the first to twenty-sixth possible implementation forms of the first aspect, and an imaging sensor for generating imaging data based on incident light through the optical apparatus. According to this configuration of the imaging apparatus, a compact and high performance imaging apparatus may be implemented.

A third aspect of an embodiment provides mobile equipment with an imaging function. In a possible implementation form of the third aspect, the mobile equipment comprises: the optical apparatus according to any one of the first to twenty-sixth possible implementation forms of the first aspect, and an imaging sensor for generating imaging data based on incident light through the optical apparatus. According to this configuration of the mobile equipment, compact mobile equipment with a high performance imaging function may be implemented.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a schematic diagram of an optical apparatus according to a first embodiment of the present disclosure,

Fig. 2 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the first embodiment of the present disclosure,

Fig. 3 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the first embodiment of the present disclosure,

Fig. 4 is a table for describing the moving range of a focusing lens according to the first embodiment of the present disclosure,

Fig. 5 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the first embodiment of the present disclosure,

Fig. 6 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the first embodiment of the present disclosure,

Fig. 7A is a graph for describing longitudinal spherical aberrations of the optical apparatus according to the first embodiment of the present disclosure,

Fig. 7B is a graph for describing astigmatic field curves of the optical apparatus according to the first embodiment of the present disclosure,

Fig. 7C is a graph for describing distortion of the optical apparatus according to the first embodiment of the present disclosure,

Fig. 8 is a schematic diagram of an optical apparatus according to a second embodiment of the present disclosure,

Fig. 9 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the second embodiment of the present disclosure,

Fig. 10 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the second embodiment of the present disclosure,

Fig. 11 is a table for describing the moving range of a focusing lens according to the second embodiment of the present disclosure,

Fig. 12 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the second embodiment of the present disclosure,

Fig. 13 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the second embodiment of the present disclosure,

Fig. 14A is a graph for describing longitudinal spherical aberrations of the optical apparatus according to the second embodiment of the present disclosure,

Fig. 14B is a graph for describing astigmatic field curves of the optical apparatus according to the second embodiment of the present disclosure,

Fig. 14C is a graph for describing distortion of the optical apparatus according to the second embodiment of the present disclosure,

Fig. 15 is a schematic diagram of an optical apparatus according to a third embodiment of the present disclosure,

Fig. 16 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the third embodiment of the present disclosure,

Fig. 17 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the third embodiment of the present disclosure,

Fig. 18 is a table for describing the moving range of a focusing lens according to the third embodiment of the present disclosure,

Fig. 19 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the third embodiment of the present disclosure,

Fig. 20 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the third embodiment of the present disclosure,

Fig. 21A is a graph for describing longitudinal spherical aberrations of the optical apparatus according to the third embodiment of the present disclosure,

Fig. 21B is a graph for describing astigmatic field curves of the optical apparatus according to the third embodiment of the present disclosure,

Fig. 21C is a graph for describing distortion of the optical apparatus according to the third embodiment of the present disclosure,

Fig. 22 is a schematic diagram of an optical apparatus according to a fourth embodiment of the present disclosure,

Fig. 23 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the fourth embodiment of the present disclosure,

Fig. 24 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the fourth embodiment of the present disclosure,

Fig. 25 is a table for describing the moving range of a focusing lens according to the fourth embodiment of the present disclosure,

Fig. 26 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the fourth embodiment of the present disclosure,

Fig. 27 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the fourth embodiment of the present disclosure,

Fig. 28A is a graph for describing longitudinal spherical aberrations of the optical apparatus according to the fourth embodiment of the present disclosure,

Fig. 28B is a graph for describing astigmatic field curves of the optical apparatus according to the fourth embodiment of the present disclosure,

Fig. 28C is a graph for describing distortion of the optical apparatus according to the fourth embodiment of the present disclosure,

Fig. 29 is a schematic diagram of an optical apparatus according to a fifth embodiment of the present disclosure,

Fig. 30 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the fifth embodiment of the present disclosure,

Fig. 31 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the fifth embodiment of the present disclosure,

Fig. 32 is a table for describing the moving range of a focusing lens according to the fifth embodiment of the present disclosure,

Fig. 33 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the fifth embodiment of the present disclosure,

Fig. 34 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the fifth embodiment of the present disclosure,

Fig. 35A is a graph for describing longitudinal spherical aberrations of the optical apparatus according to the fifth embodiment of the present disclosure,

Fig. 35B is a graph for describing astigmatic field curves of the optical apparatus according to the fifth embodiment of the present disclosure,

Fig. 35C is a graph for describing distortion of the optical apparatus according to the fifth embodiment of the present disclosure,

Fig. 36 is a schematic diagram of an optical apparatus according to a sixth embodiment of the present disclosure,

Fig. 37 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the sixth embodiment of the present disclosure,

Fig. 38 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the sixth embodiment of the present disclosure,

Fig. 39 is a table for describing the moving range of a focusing lens according to the sixth embodiment of the present disclosure,

Fig. 40 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the sixth embodiment of the present disclosure,

Fig. 41 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the sixth embodiment of the present disclosure,

Fig. 42A is a graph for describing longitudinal spherical aberrations of the optical apparatus according to the sixth embodiment of the present disclosure,

Fig. 42B is a graph for describing astigmatic field curves of the optical apparatus according to the sixth embodiment of the present disclosure,

Fig. 42C is a graph for describing distortion of the optical apparatus according to the sixth embodiment of the present disclosure,

Fig. 43 is a schematic diagram of an optical apparatus according to a seventh embodiment of the present disclosure,

Fig. 44 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the seventh embodiment of the present disclosure,

Fig. 45 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the seventh embodiment of the present disclosure,

Fig. 46 is a table for describing the moving range of a focusing lens according to the seventh embodiment of the present disclosure,

Fig. 47 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the seventh embodiment of the present disclosure,

Fig. 48 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the seventh embodiment of the present disclosure,

Fig. 49A is a graph for describing longitudinal spherical aberrations of the optical apparatus according to the seventh embodiment of the present disclosure,

Fig. 49B is a graph for describing astigmatic field curves of the optical apparatus according to the seventh embodiment of the present disclosure,

Fig. 49C is a graph for describing distortion of the optical apparatus according to the seventh embodiment of the present disclosure,

Fig. 50 is a schematic diagram of an optical apparatus according to an eighth embodiment of the present disclosure,

Fig. 51 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the eighth embodiment of the present disclosure,

Fig. 52 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the eighth embodiment of the present disclosure,

Fig. 53 is a table for describing the moving range of a focusing lens according to the eighth embodiment of the present disclosure,

Fig. 54 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the eighth embodiment of the present disclosure,

Fig. 55 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the eighth embodiment of the present disclosure,

Fig. 56A is a graph for describing longitudinal spherical aberrations of the optical apparatus according to the eighth embodiment of the present disclosure,

Fig. 56B is a graph for describing astigmatic field curves of the optical apparatus according to the eighth embodiment of the present disclosure,

Fig. 56C is a graph for describing distortion of the optical apparatus according to the eighth embodiment of the present disclosure,

Fig. 57 is a schematic diagram of an optical apparatus according to a ninth embodiment of the present disclosure,

Fig. 58 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the ninth embodiment of the present disclosure,

Fig. 59 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the ninth embodiment of the present disclosure,

Fig. 60 is a table for describing the moving range of a focusing lens according to the ninth embodiment of the present disclosure,

Fig. 61 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the ninth embodiment of the present disclosure,

Fig. 62 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the ninth embodiment of the present disclosure,

Fig. 63A is a graph for describing longitudinal spherical aberrations of the optical apparatus according to the ninth embodiment of the present disclosure,

Fig. 63B is a graph for describing astigmatic field curves of the optical apparatus according to the ninth embodiment of the present disclosure,

Fig. 63C is a graph for describing distortion of the optical apparatus according to the ninth embodiment of the present disclosure,

Fig. 64 is a table showing conditions for parameters according to the embodiments of the present disclosure,

Fig. 65 is a block diagram for describing the hardware of an imaging apparatus which may be equipped with the optical apparatus according to any one of the first to ninth embodiments of the present disclosure, and

Fig. 66 is a block diagram for describing the hardware of mobile equipment which may be equipped with the optical apparatus according to any one of the first to ninth embodiments of the present disclosure.

DESCRIPTION OF EMBODIMENTS

The following describes technical solutions of the embodiments, referring to the accompanying drawings. It will be understood that the embodiments described below are not all but just some of embodiments relating to the present disclosure. It is to be noted that all other embodiments which may be derived by a person skilled in the art based on the embodiments described below without creative efforts shall fall within the protection scope of the present disclosure.

Embodiments according to the present disclosure relate to an optical apparatus, and an imaging apparatus and mobile equipment which are equipped with the optical apparatus. The lens system of the optical apparatus includes four lens groups each having at least one lens. In these lens groups, at least one lens or lens group may be used for focusing as a focusing lens. If a first lens group has positive refractive power, a second lens group may has positive refractive power, a third lens group has negative refractive power, a fourth lens group has positive refractive power, and the second lens group is used for the focusing lens, refractive power on the object side of the focusing lens would be positive. This configuration may bring the position of the principal point closer to the object side. This contributes to shortening the entire length of the lens system.

Applicable refractive power configuration to the embodiments is not limited to the above-mentioned configuration, and the following alternatives may be applied to the embodiments. According to a first alternative, the first lens group may have positive refractive power, the second lens group may have negative refractive power, the third lens group may have positive refractive power and the fourth lens group may have positive refractive power. According to a second alternative, the first lens group may have negative refractive power, the second lens group may have positive refractive power, the third lens group may have negative refractive power and the fourth lens group has positive refractive power. According to a third alternative, the first lens group may have negative refractive power, the second lens group may have positive refractive power, the third lens group may have positive refractive power and the fourth lens group has negative refractive power. According to a fourth alternative, the first lens group may have positive refractive power, the second lens group may have negative refractive power, the third lens group may have positive refractive power and the fourth lens group has negative refractive power. These alternatives may be included in the scope of the embodiments according to the present disclosure.

The following further describes embodiments of the present disclosure.

(First Embodiment)

An optical apparatus according to a first embodiment of the present disclosure is described with reference to Fig. 1. Fig. 1 is a schematic diagram of the optical apparatus according to the first embodiment of the present disclosure. An optical apparatus 100A shown in Fig. 1 is an example of the optical apparatus according to the first embodiment of the present disclosure.

As shown in Fig. 1, the optical apparatus 100A includes, in order from the object side, a first lens group (Group 1) , a second lens group (Group 2) , a third lens group (Group 3) , and a fourth lens group (Group 4) . The optical apparatus 100A also has a filter (IR) and an image sensor (IS) on the image side of Group 4. The filter is an optical element such as an IR cut filter. To facilitate understanding of the optical apparatus, Fig. 1 schematically shows light paths P11, P12, and P13 of light incident in a direction parallel to the optical axis, and light paths P21, P22, and P23 of light incident in a direction having a certain angle to the optical axis.

Group 1 includes a lens L1 and a prism in order from the object side. Hereinafter, the object-side surface of the lens L1 may be referred to as L1_S1, and the image-side surface thereof may be referred to as L1_S2. The object-side surface of the prism may be referred to as PR_S1, and the image-side surface thereof may be referred to as PR_S2. The lens L1 is a biconvex lens. Disposing the lens L1 on the object side of the prism can set the width of a light beam incident on the surface PR_S1 smaller than the width of a light beam incident on the surface L1_S1. As a result, the prism can be made compact.

A prism is an example of a bending optical element. Although, for descriptive simplicity, light is illustrated in Fig. 1 in such a way that light transmits through the prism, the light path, in practice, is bent in the prism so that light is emitted from a light emission surface which does not face a light incident surface. A mirror may be used instead of a prism. A mirror is an example of the bending optical element. The use of a prism or a mirror may lead to realization of a folded optical apparatus.

Group 2 includes a stop, and lenses L2 and L3. Although the stop is disposed between the prism and the lens L2 in the example of Fig. 1, the position of the stop may be changed according to embodiments. Group 3 includes a lens L4. Group 4 includes a lens L5.

Hereinafter, the object-side surface of the lens L2 may be referred to as L2_S1, and the image-side surface thereof may be referred to as L2_S2. The object-side surface of the lens L3 may be referred to as L3_S1, and the image-side surface thereof may be referred to as L3_S2. The object-side surface of the lens L4 may be referred to as L4_S1, and the image-side surface thereof may be referred to as L4_S2. The object-side surface of the lens L5 may be referred to as L5_S1, and the image-side surface thereof may be referred to as L5_S2.

The lens L5 is a focusing lens and may move along the optical axis. With the movement of the lens L5, a distance D1 between the point of intersection of the surface L4_S2 and the optical axis and the point of intersection of the surface L5_S1 and the optical axis changes. Further, with the movement of the lens L5, a distance D2 between the point of intersection of the surface L5_S2 and the optical axis and the point of intersection of the filter IR and the optical axis changes. The total length of the lens system can be shortened by reducing the amount of change in the distance D1, D2.

The arrangement, and optical characteristics or the like of the individual lenses in the optical apparatus 100A are further described with reference to Figs. 2 to 6.

Fig. 2 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the first embodiment of the present disclosure. Fig. 3 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the first embodiment of the present disclosure. Fig. 4 is a table for describing the moving range of a focusing lens according to the first embodiment of the present disclosure. Fig. 5 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the first embodiment of the present disclosure. Fig. 6 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the first embodiment of the present disclosure. The aspherical coefficients may be generally defined by the following equation:

where X is a height of a point on an aspherical surface of a aspherical lens at a distance Y from the optical axis relevant to a tangential plane at an aspherical surface vertex, Y indicates the distance from the point on the aspherical surface to the optical axis, k is the conic coefficient, R is the radius of curvature, and A _i indicates an i-th (i=4, 6, 8 ... ) order aspherical coefficient.

As shown in Fig. 2, the lens system of the optical system 100A is designed so that a focal length is about 30.2 mm, an F-number is about 3.5, an entire field angle is about 10.04 degrees, and an entire length is 42.2 mm. Fig. 3 shows the radii of curvature of the individual surfaces of the lenses L1, ..., L5, and the refractive indexes and Abbe's numbers of the lenses L1, ..., L5. Fig. 3 also shows the distance along the optical axis between adjacent surfaces. For example, Fig. 3 shows that the distance between the surface L1_S1 and the surface L1_S2 of the lens L1 is 1.330 mm. This indicates that the thickness of the lens L1 along the optical axis is 1.330 mm. Fig. 3 further shows that the distance between the surface PR_S2 of the prism and the stop is 1.774 mm. The distance between the stop and the surface L2_S1 of the lens L2 is -0.269 mm in Fig. 3, which indicates that the stop is positioned 0.269 mm closer to the image side from the surface L2_S1 of the lens L2.

Referring to Fig. 3, the distance between the surface L4_S2 of the lens L4 and the surface L5_S1 of the lens L5 is D1, and the distance between the surface L5_S2 of the lens L5 and the filter is D2. This indicates that the lens L5 moves along the optical axis. According to the settings shown in Fig. 3 and the settings of the individual lenses to be described later, as shown in Fig. 4, when the object distance is infinite, D1 is about 6.110 mm and D2 is about 9.614 mm. When the object distance is 600 mm, D1 is about 4.549 mm and D2 is about 11.176 mm.

In the optical apparatus 100A, the lenses L1, ..., L5 are aspherical lenses. The fourth, sixth and eighth order aspherical coefficients of each lens are shown in Fig. 5. Parameters related to the optical characteristics of the lens system and individual lenses are shown in Fig. 6. Among the parameters shown in Fig. 6, FS is a parameter related to the position sensitivity of the focusing lens, and is given by the following Equation (1) :

M _f indicates lateral magnification of the focusing lens, and M _i (i=m, ..., n) indicates lateral magnification of an i-th lens located on an image side of the focusing lens. For example, in the case of the optical apparatus 100A, the focusing lens is the lens L5, and there is not a lens on the image side of the lens L5. In this case, M _f is lateral magnification of the lens L5, and the term of M _i is omitted. The position sensitivity of the focusing lens is provided by the ratio of the amount of change in back focus associated with the amount of movement of the focusing lens to the amount of movement of the focusing lens. Therefore, the amount of movement of the focusing lens can be reduced by increasing the position sensitivity. The reduction in the amount of movement of the focusing lens can shorten the entire length of the lens system. This makes it possible to accommodate a lens system with a long focal length (telephoto lens) in compact mobile equipment, or accommodate a lens system with a shortest shooting distance (macro lens) in compact mobile equipment.

Among the parameters shown in Fig. 6, TTL indicates the total lens length of the entire lens system. F indicates the focal length of the entire lens system. F2 indicates the focal length of Group 2. F3 indicates the focal length of Group 3. F4 indicates the focal length of Group 4. v _f indicates Abbe's number of the focusing lens (lens L5) . The application of the values of the parameters shown in Fig. 6 may provide good aberration characteristics shown in Figs. 7A to 7C. The graph in Fig. 7A shows the characteristics of longitudinal spherical aberrations in the optical apparatus 100A. The graph in Fig. 7B shows the characteristics of astigmatic field curves in the optical apparatus 100A. The graph in Fig. 7C shows the characteristics of distortion in the optical apparatus 100A.

As described above, the application of the first embodiment of the present disclosure can reduce the amount of movement of the focusing lens, and shorten the entire length of the lens system. It is also possible to provide a compact, high-performance telephoto lens and a compact, high-performance macro lens which are of sizes that can be equipped in compact mobile equipment.

(Second Embodiment)

An optical apparatus according to a second embodiment of the present disclosure is described with reference to Fig. 8. Fig. 8 is a schematic diagram of the optical apparatus according to the second embodiment of the present disclosure. An optical apparatus 100B shown in Fig. 8 is an example of the optical apparatus according to the second embodiment of the present disclosure.

As shown in Fig. 8, the optical apparatus 100B includes, in order from the object side, a first lens group (Group 1) , a second lens group (Group 2) , a third lens group (Group 3) , and a fourth lens group (Group 4) . The optical apparatus 100B also has a filter (IR) and an image sensor (IS) on the image side of Group 4. The filter is an optical element such as an IR cut filter. To facilitate understanding of the optical apparatus, Fig. 8 schematically shows light paths P11, P12, and P13 of light incident in a direction parallel to the optical axis, and light paths P21, P22, and P23 of light incident in a direction having a certain angle to the optical axis.

Group 1 includes a lens L1 and a prism in order from the object side. The lens L1 is a biconvex lens. Disposing the lens L1 on the object side of the prism can set the width of a light beam incident on the surface PR_S1 smaller than the width of a light beam incident on the surface L1_S1. As a result, the prism can be made compact.

A prism is an example of a bending optical element. Although, for descriptive simplicity, light is illustrated in Fig. 8 in such a way that light transmits through the prism, the light path, in practice, is bent in the prism so that light is emitted from a light emission surface which does not face a light incident surface. A mirror may be used instead of a prism. A mirror is an example of the bending optical element. The use of a prism or a mirror may lead to realization of a folded optical apparatus.

Group 2 includes a stop, and lenses L2 and L3. Although the stop is disposed between the prism and the lens L2 in the example of Fig. 8, the position of the stop may be changed according to embodiments. Group 3 includes a lens L4. Group 4 includes lenses L5 and L6.

Hereinafter, the object-side surface of the lens L6 may be referred to as L6_S1, and the image-side surface thereof may be referred to as L6_S2.

The lens L4 is a focusing lens and may move along the optical axis. With the movement of the lens L4, a distance D1 between the point of intersection of the surface L3_S2 and the optical axis and the point of intersection of the surface L4_S1 and the optical axis changes. Further, with the movement of the lens L4, a distance D2 between the point of intersection of the surface L4_S2 and the optical axis and the point of intersection of the surface L5_S1 and the optical axis changes. The total length of the lens system can be shortened by reducing the amount of change in the distance D1, D2.

The arrangement, and optical characteristics or the like of the individual lenses in the optical apparatus 100B are further described with reference to Figs. 9 to 13.

Fig. 9 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the second embodiment of the present disclosure. Fig. 10 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the second embodiment of the present disclosure. Fig. 11 is a table for describing the moving range of a focusing lens according to the second embodiment of the present disclosure. Fig. 12 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the second embodiment of the present disclosure. Fig. 13 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the second embodiment of the present disclosure.

As shown in Fig. 9, the lens system of the optical system 100B is designed so that a focal length is about 30.2 mm, an F-number is about 3.5, an entire field angle is about 9.89 degrees, and an entire length is 42.17 mm. Fig. 10 shows the radii of curvature of the individual surfaces of the lenses L1, ..., L6, and the refractive indexes and Abbe's numbers of the lenses L1, ..., L6.

Referring to Fig. 10, the distance between the surface L3_S2 of the lens L3 and the surface L4_S1 of the lens L4 is D1, and the distance between the surface L4_S2 of the lens L4 and the surface L5_S1 of the lens L5 is D2. This indicates that the lens L4 moves along the optical axis. According to the settings shown in Fig. 10 and the settings of the individual lenses to be described later, as shown in Fig. 11, when the object distance is infinite, D1 is about 5.452 mm and D2 is about 5.673 mm. When the object distance is 600 mm, D1 is about 4.754 mm and D2 is about 6.371 mm.

In the optical apparatus 100B, the lenses L1, ..., L6 are aspherical lenses. The fourth, sixth and eighth order aspherical coefficients of each lens are shown in Fig. 12. Parameters related to the optical characteristics of the lens system and individual lenses are shown in Fig. 13. Among the parameters shown in Fig. 13, FS is a parameter related to the position sensitivity of the focusing lens, and is given by the Equation (1) .

For example, in the case of the optical apparatus 100B, the focusing lens is the lens L4, and there are the lenses L5 and L6 on the image side of the lens L4. In this case, M _f is lateral magnification of the lens L4, and the term of M _i is the product of lateral magnification M ₅ of the lens L5 and lateral magnification M ₆ of the lens L6.

Among the parameters shown in Fig. 13, TTL indicates the total lens length of the entire lens system. F indicates the focal length of the entire lens system. F2 indicates the focal length of Group 2. F3 indicates the focal length of Group 3. F4 indicates the focal length of Group 4. v _f indicates Abbe's number of the focusing lens (lens L4) . The application of the values of the parameters shown in Fig. 13 may provide good aberration characteristics shown in Figs. 14A to 14C. The graph in Fig. 14A shows the characteristics of longitudinal spherical aberrations in the optical apparatus 100B. The graph in Fig. 14B shows the characteristics of astigmatic field curves in the optical apparatus 100B. The graph in Fig. 14C shows the characteristics of distortion in the optical apparatus 100B.

As described above, the application of the second embodiment of the present disclosure can reduce the amount of movement of the focusing lens, and shorten the entire length of the lens system. It is also possible to provide a compact, high-performance telephoto lens and a compact, high-performance macro lens which are of sizes that can be equipped in compact mobile equipment.

(Third Embodiment)

An optical apparatus according to a third embodiment of the present disclosure is described with reference to Fig. 15. Fig. 15 is a schematic diagram of the optical apparatus according to the third embodiment of the present disclosure. An optical apparatus 100C shown in Fig. 15 is an example of the optical apparatus according to the third embodiment of the present disclosure.

As shown in Fig. 15, the optical apparatus 100C includes, in order from the object side, a first lens group (Group 1) , a second lens group (Group 2) , a third lens group (Group 3) , and a fourth lens group (Group 4) . The optical apparatus 100C also has a filter (IR) and an image sensor (IS) on the image side of Group 4. The filter is an optical element such as an IR cut filter. To facilitate understanding of the optical apparatus, Fig. 15 schematically shows light paths P11, P12, and P13 of light incident in a direction parallel to the optical axis, and light paths P21, P22, and P23 of light incident in a direction having a certain angle to the optical axis.

A prism is an example of a bending optical element. Although, for descriptive simplicity, light is illustrated in Fig. 15 in such a way that light transmits through the prism, the light path, in practice, is bent in the prism so that light is emitted from a light emission surface which does not face a light incident surface. A mirror may be used instead of a prism. A mirror is an example of the bending optical element. The use of a prism or a mirror may lead to realization of a folded optical apparatus.

Group 2 includes a stop, and lenses L2, L3, and L4. Although the stop is disposed between the prism and the lens L2 in the example of Fig. 15, the position of the stop may be changed according to embodiments. Group 3 includes a lens L5. Group 4 includes a lens L6.

The lens L3 is a focusing lens and may move along the optical axis. With the movement of the lens L3, a distance D1 between the point of intersection of the surface L2_S2 and the optical axis and the point of intersection of the surface L3_S1 and the optical axis changes. Further, with the movement of the lens L3, a distance D2 between the point of intersection of the surface L3_S2 and the optical axis and the point of intersection of the surface L4_S1 and the optical axis changes. The total length of the lens system can be shortened by reducing the amount of change in the distance D1, D2.

The arrangement, and optical characteristics or the like of the individual lenses in the optical apparatus 100C are further described with reference to Figs. 16 to 20.

Fig. 16 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the third embodiment of the present disclosure. Fig. 17 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the third embodiment of the present disclosure. Fig. 18 is a table for describing the moving range of a focusing lens according to the third embodiment of the present disclosure. Fig. 19 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the third embodiment of the present disclosure. Fig. 20 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the third embodiment of the present disclosure.

As shown in Fig. 16, the lens system of the optical system 100C is designed so that a focal length is about 30.2 mm, an F-number is about 3.5, an entire field angle is about 10.04 degrees, and an entire length is 42.16 mm. Fig. 17 shows the radii of curvature of the individual surfaces of the lenses L1, ..., L6, and the refractive indexes and Abbe's numbers of the lenses L1, ..., L6.

Referring to Fig. 16, the distance between the surface L2_S2 of the lens L2 and the surface L3_S1 of the lens L3 is D1, and the distance between the surface L3_S2 of the lens L3 and the surface L4_S1 of the lens L4 is D2. This indicates that the lens L3 moves along the optical axis. According to the settings shown in Fig. 16 and the settings of the individual lenses to be described later, as shown in Fig. 17, when the object distance is infinite, D1 is about 0.499 mm and D2 is about 5.384 mm. When the object distance is 600 mm, D1 is about 1.093 mm and D2 is about 4.791 mm.

In the optical apparatus 100C, the lenses L1, ..., L6 are aspherical lenses. The fourth, sixth and eighth order aspherical coefficients of each lens are shown in Fig. 19. Parameters related to the optical characteristics of the lens system and individual lenses are shown in Fig. 20. Among the parameters shown in Fig. 20, FS is a parameter related to the position sensitivity of the focusing lens, and is given by the Equation (1) .

For example, in the case of the optical apparatus 100C, the focusing lens is the lens L3, and there are the lenses L4, L5, and L6 on the image side of the lens L3. In this case, M _f is lateral magnification of the lens L3, and the term of M _i is the product of lateral magnification M ₄ of the lens L4, lateral magnification M ₅ of the lens L5, and lateral magnification M ₆ of the lens L6.

Among the parameters shown in Fig. 20, TTL indicates the total lens length of the entire lens system. F indicates the focal length of the entire lens system. F2 indicates the focal length of Group 2. F3 indicates the focal length of Group 3. F4 indicates the focal length of Group 4. v _f indicates Abbe's number of the focusing lens (lens L4) . The application of the values of the parameters shown in Fig. 20 may provide good aberration characteristics shown in Figs. 21A to 21C. The graph in Fig. 21A shows the characteristics of longitudinal spherical aberrations in the optical apparatus 100C. The graph in Fig. 21B shows the characteristics of astigmatic field curves in the optical apparatus 100C. The graph in Fig. 21C shows the characteristics of distortion in the optical apparatus 100C.

As described above, the application of the third embodiment of the present disclosure can reduce the amount of movement of the focusing lens, and shorten the entire length of the lens system. It is also possible to provide a compact, high-performance telephoto lens and a compact, high-performance macro lens which are of sizes that can be equipped in compact mobile equipment.

(Fourth Embodiment)

An optical apparatus according to a fourth embodiment of the present disclosure is described with reference to Fig. 22. Fig. 22 is a schematic diagram of the optical apparatus according to the fourth embodiment of the present disclosure. An optical apparatus 100D shown in Fig. 22 is an example of the optical apparatus according to the fourth embodiment of the present disclosure.

As shown in Fig. 22, the optical apparatus 100D includes, in order from the object side, a first lens group (Group 1) , a second lens group (Group 2) , a third lens group (Group 3) , and a fourth lens group (Group 4) . The optical apparatus 100D also has a filter (IR) and an image sensor (IS) on the image side of Group 4. The filter is an optical element such as an IR cut filter. To facilitate understanding of the optical apparatus, Fig. 22 schematically shows light paths P11, P12, and P13 of light incident in a direction parallel to the optical axis, and light paths P21, P22, and P23 of light incident in a direction having a certain angle to the optical axis.

A prism is an example of a bending optical element. Although, for descriptive simplicity, light is illustrated in Fig. 22 in such a way that light transmits through the prism, the light path, in practice, is bent in the prism so that light is emitted from a light emission surface which does not face a light incident surface. A mirror may be used instead of a prism. A mirror is an example of the bending optical element. The use of a prism or a mirror may lead to realization of a folded optical apparatus.

Group 2 includes a stop, and lenses L2, L3, L4, and L5. Although the stop is disposed between the prism and the lens L2 in the example of Fig. 22, the position of the stop may be changed according to embodiments. Group 3 includes a lens L6. Group 4 includes a lens L7. Hereinafter, the object-side surface of the lens L7 may be referred to as L7_S1, and the image-side surface thereof may be referred to as L7_S2.

Group 2 is a focusing lens group and the entire lens groups may move along the optical axis. With the movement of Group 2, a distance D1 between the point of intersection of the surface PR_S2 and the optical axis and the point of intersection of the surface L2_S1 and the optical axis changes. Further, with the movement of Group 2, a distance D2 between the point of intersection of the surface L5_S2 and the optical axis and the point of intersection of the surface L6_S1 and the optical axis changes. The total length of the lens system can be shortened by reducing the amount of change in the distance D1, D2.

The arrangement, and optical characteristics or the like of the individual lenses in the optical apparatus 100D are further described with reference to Figs. 23 to 27.

Fig. 23 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the fourth embodiment of the present disclosure. Fig. 24 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the fourth embodiment of the present disclosure. Fig. 25 is a table for describing the moving range of a focusing lens according to the fourth embodiment of the present disclosure. Fig. 26 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the fourth embodiment of the present disclosure. Fig. 27 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the fourth embodiment of the present disclosure.

As shown in Fig. 23, the lens system of the optical system 100D is designed so that a focal length is about 30.2 mm, an F-number is about 3.5, an entire field angle is about 10.04 degrees, and an entire length is 40.76 mm. Fig. 24 shows the radii of curvature of the individual surfaces of the lenses L1, ..., L7, and the refractive indexes and Abbe's numbers of the lenses L1, ..., L7.

Referring to Fig. 24, the distance between the surface PR_S2 of the prism and the surface L2_S1 of the lens L2 is D1, and the distance between the surface L5_S2 of the lens L5 and the surface L6_S1 of the lens L6 is D2. This indicates that the entire Group 2 moves along the optical axis. According to the settings shown in Fig. 24 and the settings of the individual lenses to be described later, as shown in Fig. 25, when the object distance is infinite, D1 is about 1.562 mm and D2 is about 4.695 mm. When the object distance is 600 mm, D1 is about 1.064 mm and D2 is about 5.194 mm.

In the optical apparatus 100D, the lenses L1, ..., L7 are aspherical lenses. The fourth, sixth and eighth order aspherical coefficients of each lens are shown in Fig. 26. Parameters related to the optical characteristics of the lens system and individual lenses are shown in Fig. 27. Among the parameters shown in Fig. 27, FS is a parameter related to the position sensitivity of the focusing lens, and is given by the Equation (1) .

For example, in the case of the optical apparatus 100D, the focusing lens group is Group 2, and there are the lenses L6 and L7 on the image side of Group 2. In this case, M _f is lateral magnification of the entire Group 2, and the term of M _i is the product of lateral magnification M ₆ of the lens L6, and lateral magnification M ₇ of the lens L7.

Among the parameters shown in Fig. 27, TTL indicates the total lens length of the entire lens system. F indicates the focal length of the entire lens system. F2 indicates the focal length of Group 2. F3 indicates the focal length of Group 3. F4 indicates the focal length of Group 4. v _f indicates Abbe's number of the focusing lens group (Group 2) . The application of the values of the parameters shown in Fig. 27 may provide good aberration characteristics shown in Figs. 28A to 28C. The graph in Fig. 28A shows the characteristics of longitudinal spherical aberrations in the optical apparatus 100D. The graph in Fig. 28B shows the characteristics of astigmatic field curves in the optical apparatus 100D. The graph in Fig. 28C shows the characteristics of distortion in the optical apparatus 100D.

As described above, the application of the fourth embodiment of the present disclosure can reduce the amount of movement of the focusing lens, and shorten the entire length of the lens system. It is also possible to provide a compact, high-performance telephoto lens and a compact, high-performance macro lens which are of sizes that can be equipped in compact mobile equipment.

(Fifth Embodiment)

An optical apparatus according to a fifth embodiment of the present disclosure is described with reference to Fig. 29. Fig. 29 is a schematic diagram of the optical apparatus according to the fifth embodiment of the present disclosure. An optical apparatus 100E shown in Fig. 29 is an example of the optical apparatus according to the fifth embodiment of the present disclosure.

As shown in Fig. 29, the optical apparatus 100E includes, in order from the object side, a first lens group (Group 1) , a second lens group (Group 2) , a third lens group (Group 3) , and a fourth lens group (Group 4) . The optical apparatus 100E also has a filter (IR) and an image sensor (IS) on the image side of Group 4. The filter is an optical element such as an IR cut filter. To facilitate understanding of the optical apparatus, Fig. 29 schematically shows light paths P11, P12, and P13 of light incident in a direction parallel to the optical axis, and light paths P21, P22, and P23 of light incident in a direction having a certain angle to the optical axis.

A prism is an example of a bending optical element. Although, for descriptive simplicity, light is illustrated in Fig. 29 in such a way that light transmits through the prism, the light path, in practice, is bent in the prism so that light is emitted from a light emission surface which does not face a light incident surface. A mirror may be used instead of a prism. A mirror is an example of the bending optical element. The use of a prism or a mirror may lead to realization of a folded optical apparatus.

Group 2 includes a stop, and lenses L2, L3, L4, and L5. Although the stop is disposed between the prism and the lens L2 in the example of Fig. 29, the position of the stop may be changed according to embodiments. Group 3 includes a lens L6. Group 4 includes a lens L7.

The lens L6 is a focusing lens and may move along the optical axis. With the movement of the lens L6, a distance D1 between the point of intersection of the surface L5_S2 and the optical axis and the point of intersection of the surface L6_S1 and the optical axis changes. Further, with the movement of the lens L6, a distance D2 between the point of intersection of the surface L6_S2 and the optical axis and the point of intersection of the surface L7_S1 and the optical axis changes. The total length of the lens system can be shortened by reducing the amount of change in the distance D1, D2.

The arrangement, and optical characteristics or the like of the individual lenses in the optical apparatus 100E are further described with reference to Figs. 30 to 34.

Fig. 30 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the fifth embodiment of the present disclosure. Fig. 31 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the fifth embodiment of the present disclosure. Fig. 32 is a table for describing the moving range of a focusing lens according to the fifth embodiment of the present disclosure. Fig. 33 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the fifth embodiment of the present disclosure. Fig. 34 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the fifth embodiment of the present disclosure.

As shown in Fig. 30, the lens system of the optical system 100E is designed so that a focal length is about 30.2 mm, an F-number is about 3.5, an entire field angle is about 9.89 degrees, and an entire length is 40.67 mm. Fig. 31 shows the radii of curvature of the individual surfaces of the lenses L1, ..., L7, and the refractive indexes and Abbe's numbers of the lenses L1, ..., L7.

Referring to Fig. 31, the distance between the surface L5_S2 of the lens L5 and the surface L6_S1 of the lens L6 is D1, and the distance between the surface L6_S2 of the lens L6 and the surface L7_S1 of the lens L7 is D2. This indicates that the lens L6 moves along the optical axis. According to the settings shown in Fig. 31 and the settings of the individual lenses to be described later, as shown in Fig. 32, when the object distance is infinite, D1 is about 4.453 mm and D2 is about 4.641 mm. When the object distance is 600 mm, D1 is about 4.954 mm and D2 is about 4.140 mm.

In the optical apparatus 100E, the lenses L1, ..., L7 are aspherical lenses. The fourth, sixth and eighth order aspherical coefficients of each lens are shown in Fig. 33. Parameters related to the optical characteristics of the lens system and individual lenses are shown in Fig. 34. Among the parameters shown in Fig. 34, FS is a parameter related to the position sensitivity of the focusing lens, and is given by the Equation (1) .

For example, in the case of the optical apparatus 100E, the focusing lens is the lens L6, and there are the lens L7 on the image side of the lens L6. In this case, M _f is lateral magnification of the lens L6, and the term of M _i is lateral magnification M ₇ of the lens L7.

Among the parameters shown in Fig. 34, TTL indicates the total lens length of the entire lens system. F indicates the focal length of the entire lens system. F2 indicates the focal length of Group 2. F3 indicates the focal length of Group 3. F4 indicates the focal length of Group 4. v _f indicates Abbe's number of the focusing lens (lens 6) . The application of the values of the parameters shown in Fig. 34 may provide good aberration characteristics shown in Figs. 35A to 35C. The graph in Fig. 35A shows the characteristics of longitudinal spherical aberrations in the optical apparatus 100E. The graph in Fig. 35B shows the characteristics of astigmatic field curves in the optical apparatus 100E. The graph in Fig. 35C shows the characteristics of distortion in the optical apparatus 100E.

As described above, the application of the fifth embodiment of the present disclosure can reduce the amount of movement of the focusing lens, and shorten the entire length of the lens system. It is also possible to provide a compact, high-performance telephoto lens and a compact, high-performance macro lens which are of sizes that can be equipped in compact mobile equipment.

(Sixth Embodiment)

An optical apparatus according to a sixth embodiment of the present disclosure is described with reference to Fig. 36. Fig. 36 is a schematic diagram of the optical apparatus according to the sixth embodiment of the present disclosure. An optical apparatus 100F shown in Fig. 36 is an example of the optical apparatus according to the sixth embodiment of the present disclosure.

As shown in Fig. 36, the optical apparatus 100F includes, in order from the object side, a first lens group (Group 1) , a second lens group (Group 2) , a third lens group (Group 3) , and a fourth lens group (Group 4) . The optical apparatus 100F also has a filter (IR) and an image sensor (IS) on the image side of Group 4. The filter is an optical element such as an IR cut filter. To facilitate understanding of the optical apparatus, Fig. 36 schematically shows light paths P11, P12, and P13 of light incident in a direction parallel to the optical axis, and light paths P21, P22, and P23 of light incident in a direction having a certain angle to the optical axis.

Group 1 includes a lens L1 and a prism in order from the object side. The lens L1 has a convex shape on the object side thereof and a concave shape on the image side thereof.

A prism is an example of a bending optical element. Although, for descriptive simplicity, light is illustrated in Fig. 36 in such a way that light transmits through the prism, the light path, in practice, is bent in the prism so that light is emitted from a light emission surface which does not face a light incident surface. A mirror may be used instead of a prism. A mirror is an example of the bending optical element. The use of a prism or a mirror may lead to realization of a folded optical apparatus.

Group 2 includes a stop, and lenses L2, L3, and L4. Although the stop is disposed between the prism and the lens L2 in the example of Fig. 36, the position of the stop may be changed according to embodiments. Group 3 includes a lens L5. Group 4 includes lenses L6 and L7.

The lens L5 is a focusing lens and may move along the optical axis. With the movement of the lens L5, a distance D1 between the point of intersection of the surface L4_S2 and the optical axis and the point of intersection of the surface L5_S1 and the optical axis changes. Further, with the movement of the lens L5, a distance D2 between the point of intersection of the surface L5_S2 and the optical axis and the point of intersection of the surface L6_S1 and the optical axis changes. The total length of the lens system can be shortened by reducing the amount of change in the distance D1, D2.

The arrangement, and optical characteristics or the like of the individual lenses in the optical apparatus 100F are further described with reference to Figs. 37 to 41.

Fig. 37 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the sixth embodiment of the present disclosure. Fig. 38 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the sixth embodiment of the present disclosure. Fig. 39 is a table for describing the moving range of a focusing lens according to the sixth embodiment of the present disclosure. Fig. 40 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the sixth embodiment of the present disclosure. Fig. 41 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the sixth embodiment of the present disclosure.

As shown in Fig. 37, the lens system of the optical system 100F is designed so that a focal length is about 9.02 mm, an F-number is about 2.7, an entire field angle is about 32.76 degrees, and an entire length is 30.81 mm. Fig. 38 shows the radii of curvature of the individual surfaces of the lenses L1, ..., L7, and the refractive indexes and Abbe's numbers of the lenses L1, ..., L7.

Referring to Fig. 38, the distance between the surface L4_S2 of the lens L4 and the surface L5_S1 of the lens L5 is D1, and the distance between the surface L5_S2 of the lens L5 and the surface L6_S1 of the lens L6 is D2. This indicates that the lens L5 moves along the optical axis. According to the settings shown in Fig. 38 and the settings of the individual lenses to be described later, as shown in Fig. 39, when the object distance is infinite, D1 is about 4.453 mm and D2 is about 4.641 mm. When the object distance is 600 mm, D1 is about 4.954 mm and D2 is about 4.140 mm.

In the optical apparatus 100F, the lenses L1, ..., L6 are aspherical lenses, and the lens L7 is a spherical lens. The fourth, sixth and eighth order aspherical coefficients of each aspherical lens are shown in Fig. 40. Parameters related to the optical characteristics of the lens system and individual lenses are shown in Fig. 41. Among the parameters shown in Fig. 41, FS is a parameter related to the position sensitivity of the focusing lens, and is given by the Equation (1) .

For example, in the case of the optical apparatus 100F, the focusing lens is the lens L5, and there are the lenses L6 and L7 on the image side of the lens L5. In this case, M _f is lateral magnification of the lens L5, and the term of M _i is the product of lateral magnification M ₆ of the lens L6 and lateral magnification M ₇ of the lens L7.

Among the parameters shown in Fig. 41, TTL indicates the total lens length of the entire lens system. F indicates the focal length of the entire lens system. F2 indicates the focal length of Group 2. F3 indicates the focal length of Group 3. F4 indicates the focal length of Group 4. v _f indicates Abbe's number of the focusing lens (lens 5) . The application of the values of the parameters shown in Fig. 41 may provide good aberration characteristics shown in Figs. 42A to 42C. The graph in Fig. 42A shows the characteristics of longitudinal spherical aberrations in the optical apparatus 100F. The graph in Fig. 42B shows the characteristics of astigmatic field curves in the optical apparatus 100F. The graph in Fig. 42C shows the characteristics of distortion in the optical apparatus 100F.

As described above, the application of the sixth embodiment of the present disclosure can reduce the amount of movement of the focusing lens, and shorten the entire length of the lens system. It is also possible to provide a compact, high-performance telephoto lens and a compact, high-performance macro lens which are of sizes that can be equipped in compact mobile equipment.

(Seventh Embodiment)

An optical apparatus according to a seventh embodiment of the present disclosure is described with reference to Fig. 43. Fig. 43 is a schematic diagram of the optical apparatus according to the seventh embodiment of the present disclosure. An optical apparatus 100G shown in Fig. 43 is an example of the optical apparatus according to the seventh embodiment of the present disclosure.

As shown in Fig. 43, the optical apparatus 100G includes, in order from the object side, a first lens group (Group 1) , a second lens group (Group 2) , a third lens group (Group 3) , and a fourth lens group (Group 4) . The optical apparatus 100G also has a filter (IR) and an image sensor (IS) on the image side of Group 4. The filter is an optical element such as an IR cut filter. To facilitate understanding of the optical apparatus, Fig. 43 schematically shows light paths P11, P12, and P13 of light incident in a direction parallel to the optical axis, and light paths P21, P22, and P23 of light incident in a direction having a certain angle to the optical axis.

A prism is an example of a bending optical element. Although, for descriptive simplicity, light is illustrated in Fig. 43 in such a way that light transmits through the prism, the light path, in practice, is bent in the prism so that light is emitted from a light emission surface which does not face a light incident surface. A mirror may be used instead of a prism. A mirror is an example of the bending optical element. The use of a prism or a mirror may lead to realization of a folded optical apparatus.

Group 2 includes a stop, and lenses L2, L3, L4, and L5. Although the stop is disposed between the prism and the lens L2 in the example of Fig. 43, the position of the stop may be changed according to embodiments. Group 3 includes a lens L6. Group 4 includes a lens L7.

The arrangement, and optical characteristics or the like of the individual lenses in the optical apparatus 100G are further described with reference to Figs. 44 to 48.

Fig. 44 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the seventh embodiment of the present disclosure. Fig. 45 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the seventh embodiment of the present disclosure. Fig. 46 is a table for describing the moving range of a focusing lens according to the seventh embodiment of the present disclosure. Fig. 47 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the seventh embodiment of the present disclosure. Fig. 48 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the seventh embodiment of the present disclosure.

As shown in Fig. 44, the lens system of the optical system 100G is designed so that a focal length is about 58.09 mm, an F-number is about 3.5, an entire field angle is about 5.16 degrees, and an entire length is 76.23 mm. Fig. 45 shows the radii of curvature of the individual surfaces of the lenses L1, ..., L7, and the refractive indexes and Abbe's numbers of the lenses L1, ..., L7.

Referring to Fig. 45, the distance between the surface L5_S2 of the lens L5 and the surface L6_S1 of the lens L6 is D1, and the distance between the surface L6_S2 of the lens L6 and the surface L7_S1 of the lens L7 is D2. This indicates that the lens L6 moves along the optical axis. According to the settings shown in Fig. 45 and the settings of the individual lenses to be described later, as shown in Fig. 46, when the object distance is infinite, D1 is about 8.54 mm and D2 is about 8.94 mm. When the object distance is 100 mm, D1 is about 9.951 mm and D2 is about 7.54 mm.

In the optical apparatus 100G, the lenses L1, ..., L7 are aspherical lenses. The fourth, sixth and eighth order aspherical coefficients of each aspherical lens are shown in Fig. 47. Parameters related to the optical characteristics of the lens system and individual lenses are shown in Fig. 48. Among the parameters shown in Fig. 48, FS is a parameter related to the position sensitivity of the focusing lens, and is given by the Equation (1) .

For example, in the case of the optical apparatus 100G, the focusing lens is the lens L6, and there is the lens L7 on the image side of the lens L6. In this case, M _f is lateral magnification of the lens L6, and the term of M _i is lateral magnification M ₇ of the lens L7.

Among the parameters shown in Fig. 48, TTL indicates the total lens length of the entire lens system. F indicates the focal length of the entire lens system. F2 indicates the focal length of Group 2. F3 indicates the focal length of Group 3. F4 indicates the focal length of Group 4. v _f indicates Abbe's number of the focusing lens (lens 6) . The application of the values of the parameters shown in Fig. 48 may provide good aberration characteristics shown in Figs. 49A to 49C. The graph in Fig. 49A shows the characteristics of longitudinal spherical aberrations in the optical apparatus 100G. The graph in Fig. 49B shows the characteristics of astigmatic field curves in the optical apparatus 100G. The graph in Fig. 49C shows the characteristics of distortion in the optical apparatus 100G.

As described above, the application of the seventh embodiment of the present disclosure can reduce the amount of movement of the focusing lens, and shorten the entire length of the lens system. It is also possible to provide a compact, high-performance telephoto lens and a compact, high-performance macro lens which are of sizes that can be equipped in compact mobile equipment.

(Eighth Embodiment)

An optical apparatus according to an eighth embodiment of the present disclosure is described with reference to Fig. 50. Fig. 50 is a schematic diagram of the optical apparatus according to the eighth embodiment of the present disclosure. An optical apparatus 100H shown in Fig. 50 is an example of the optical apparatus according to the eighth embodiment of the present disclosure.

As shown in Fig. 50, the optical apparatus 100H includes, in order from the object side, a first lens group (Group 1) , a second lens group (Group 2) , a third lens group (Group 3) , and a fourth lens group (Group 4) . The optical apparatus 100H also has a filter (IR) and an image sensor (IS) on the image side of Group 4. The filter is an optical element such as an IR cut filter. To facilitate understanding of the optical apparatus, Fig. 50 schematically shows light paths P11, P12, and P13 of light incident in a direction parallel to the optical axis, and light paths P21, P22, and P23 of light incident in a direction having a certain angle to the optical axis.

A prism is an example of a bending optical element. Although, for descriptive simplicity, light is illustrated in Fig. 50 in such a way that light transmits through the prism, the light path, in practice, is bent in the prism so that light is emitted from a light emission surface which does not face a light incident surface. A mirror may be used instead of a prism. A mirror is an example of the bending optical element. The use of a prism or a mirror may lead to realization of a folded optical apparatus.

Group 2 includes lenses L2, L3, and L4. Although the stop is omitted in the example of Fig. 50, the stop may be disposed at an adequate position according to embodiments. Group 3 includes a lens L5. Group 4 includes lenses L6 and L7.

The arrangement, and optical characteristics or the like of the individual lenses in the optical apparatus 100H are further described with reference to Figs. 51 to 55.

Fig. 51 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the eighth embodiment of the present disclosure. Fig. 52 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the eighth embodiment of the present disclosure. Fig. 53 is a table for describing the moving range of a focusing lens according to the eighth embodiment of the present disclosure. Fig. 54 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the eighth embodiment of the present disclosure. Fig. 55 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the eighth embodiment of the present disclosure.

As shown in Fig. 51, the lens system of the optical system 100H is designed so that a focal length is about 10.99 mm, an F-number is about 2.7, an entire field angle is about 26.62 degrees, and an entire length is 33.73 mm. Fig. 52 shows the radii of curvature of the individual surfaces of the lenses L1, ..., L7, and the refractive indexes and Abbe's numbers of the lenses L1, ..., L7.

Referring to Fig. 52, the distance between the surface L4_S2 of the lens L4 and the surface L5_S1 of the lens L5 is D1, and the distance between the surface L5_S2 of the lens L5 and the surface L6_S1 of the lens L6 is D2. This indicates that the lens L5 moves along the optical axis. According to the settings shown in Fig. 52 and the settings of the individual lenses to be described later, as shown in Fig. 53, when the object distance is infinite, D1 is about 4.464 mm and D2 is about 3.993 mm. When the object distance is 100 mm, D1 is about 4.003 mm and D2 is about 4.462 mm.

In the optical apparatus 100H, the lenses L1, L2, L5, ..., L7 are aspherical lenses. The fourth, sixth and eighth order aspherical coefficients of each aspherical lens are shown in Fig. 54. Parameters related to the optical characteristics of the lens system and individual lenses are shown in Fig. 55. Among the parameters shown in Fig. 55, FS is a parameter related to the position sensitivity of the focusing lens, and is given by the Equation (1) .

For example, in the case of the optical apparatus 100H, the focusing lens is the lens L5, and there are the lenses L6 and L7 on the image side of the lens L5. In this case, M _f is lateral magnification of the lens L5, and the term of M _i is the product of lateral magnification M ₆ of the lens L6 and lateral magnification M ₇ of the lens L7.

Among the parameters shown in Fig. 55, TTL indicates the total lens length of the entire lens system. F indicates the focal length of the entire lens system. F2 indicates the focal length of Group 2. F3 indicates the focal length of Group 3. F4 indicates the focal length of Group 4. v _f indicates Abbe's number of the focusing lens (lens 5) . The application of the values of the parameters shown in Fig. 55 may provide good aberration characteristics shown in Figs. 56A to 56C. The graph in Fig. 56A shows the characteristics of longitudinal spherical aberrations in the optical apparatus 100H. The graph in Fig. 56B shows the characteristics of astigmatic field curves in the optical apparatus 100H. The graph in Fig. 56C shows the characteristics of distortion in the optical apparatus 100H.

As described above, the application of the eighth embodiment of the present disclosure can reduce the amount of movement of the focusing lens, and shorten the entire length of the lens system. It is also possible to provide a compact, high-performance telephoto lens and a compact, high-performance macro lens which are of sizes that can be equipped in compact mobile equipment.

(Ninth Embodiment)

An optical apparatus according to a ninth embodiment of the present disclosure is described with reference to Fig. 57. Fig. 57 is a schematic diagram of the optical apparatus according to the ninth embodiment of the present disclosure. An optical apparatus 100I shown in Fig. 57 is an example of the optical apparatus according to the ninth embodiment of the present disclosure.

As shown in Fig. 57, the optical apparatus 100I includes, in order from the object side, a first lens group (Group 1) , a second lens group (Group 2) , a third lens group (Group 3) , and a fourth lens group (Group 4) . The optical apparatus 100I also has a filter (IR) and an image sensor (IS) on the image side of Group 4. The filter is an optical element such as an IR cut filter. To facilitate understanding of the optical apparatus, Fig. 57 schematically shows light paths P11, P12, and P13 of light incident in a direction parallel to the optical axis, and light paths P21, P22, and P23 of light incident in a direction having a certain angle to the optical axis.

A prism is an example of a bending optical element. Although, for descriptive simplicity, light is illustrated in Fig. 57 in such a way that light transmits through the prism, the light path, in practice, is bent in the prism so that light is emitted from a light emission surface which does not face a light incident surface. A mirror may be used instead of a prism. A mirror is an example of the bending optical element. The use of a prism or a mirror may lead to realization of a folded optical apparatus.

Group 2 includes a stop and lenses L2, L3, and L4. Although the stop is disposed between the prism and the lens L2 in the example of Fig. 57, the position of the stop may be changed according to embodiments. Group 3 includes a lens L5. Group 4 includes lenses L6 and L7.

The arrangement, and optical characteristics or the like of the individual lenses in the optical apparatus 100I are further described with reference to Figs. 58 to 62.

Fig. 58 is a table for describing the optical characteristics and the entire length of the optical apparatus according to the ninth embodiment of the present disclosure. Fig. 59 is a table for describing the arrangement, the shapes, and characteristics of individual lenses included in the optical apparatus according to the ninth embodiment of the present disclosure. Fig. 60 is a table for describing the moving range of a focusing lens according to the ninth embodiment of the present disclosure. Fig. 61 is a table showing aspherical coefficients of aspherical lenses included in the optical apparatus according to the ninth embodiment of the present disclosure. Fig. 62 is a table for describing parameters indicating the characteristics of individual lenses and a lens system which are included in the optical apparatus according to the ninth embodiment of the present disclosure.

As shown in Fig. 58, the lens system of the optical system 100I is designed so that a focal length is about 21.06 mm, an F-number is about 3.0, an entire field angle is about 14.07 degrees, and an entire length is 30.32 mm. Fig. 59 shows the radii of curvature of the individual surfaces of the lenses L1, ..., L7, and the refractive indexes and Abbe's numbers of the lenses L1, ..., L7.

Referring to Fig. 59, the distance between the surface L4_S2 of the lens L4 and the surface L5_S1 of the lens L5 is D1, and the distance between the surface L5_S2 of the lens L5 and the surface L6_S1 of the lens L6 is D2. This indicates that the lens L5 moves along the optical axis. According to the settings shown in Fig. 59 and the settings of the individual lenses to be described later, as shown in Fig. 60, when the object distance is infinite, D1 is about 4.520 mm and D2 is about 3.977 mm. When the object distance is 300 mm, D1 is about 3.966 mm and D2 is about 4.496 mm.

In the optical apparatus 100I, the lenses L1, ..., L7 are aspherical lenses. The fourth, sixth and eighth order aspherical coefficients of each aspherical lens are shown in Fig. 61. Parameters related to the optical characteristics of the lens system and individual lenses are shown in Fig. 62. Among the parameters shown in Fig. 62, FS is a parameter related to the position sensitivity of the focusing lens, and is given by the Equation (1) .

For example, in the case of the optical apparatus 100I, the focusing lens is the lens L5, and there are the lenses L6 and L7 on the image side of the lens L5. In this case, M _f is lateral magnification of the lens L5, and the term of M _i is the product of lateral magnification M ₆ of the lens L6 and lateral magnification M ₇ of the lens L7.

Among the parameters shown in Fig. 62, TTL indicates the total lens length of the entire lens system. F indicates the focal length of the entire lens system. F2 indicates the focal length of Group 2. F3 indicates the focal length of Group 3. F4 indicates the focal length of Group 4. v _f indicates Abbe's number of the focusing lens (lens 5) . The application of the values of the parameters shown in Fig. 62 may provide good aberration characteristics shown in Figs. 63A to 63C. The graph in Fig. 63A shows the characteristics of longitudinal spherical aberrations in the optical apparatus 100I. The graph in Fig. 63B shows the characteristics of astigmatic field curves in the optical apparatus 100I. The graph in Fig. 63C shows the characteristics of distortion in the optical apparatus 100I.

As described above, the application of the ninth embodiment of the present disclosure can reduce the amount of movement of the focusing lens, and shorten the entire length of the lens system. It is also possible to provide a compact, high-performance telephoto lens and a compact, high-performance macro lens which are of sizes that can be equipped in compact mobile equipment.

(Parameter Conditions)

According to the examples of the parameter settings and the optical characteristics according to the first to ninth embodiments described above, various aberrations can be reduced while suppressing the entire length of the lens system by applying the parameter settings conforming to the conditions shown in Fig. 64. Fig. 64 is a table for describing the conditions for the parameters according to the embodiments of the present disclosure.

For example, by setting a threshold value TH _MAX, which is the upper limit of FS. The TH _MAX regarding FS may be configured to be smaller than 4 as shown in the First Condition of Fig. 64. A threshold value TH _MIN may also be set as the lower limit of FS. Setting TH _MAX may reduce the amount of movement of the focusing lens and the lens system may be accommodated in compact mobile equipment. For example, setting TH _MAX of FS makes it possible to prevent the lateral magnification of the focusing lens from becoming too large. As the lateral magnification of the focusing lens is increased, the refractive power tends to increase, thus increasing aberrations. Setting the threshold value TH _MAX of FS as mentioned above can suppress excessive increases in aberrations, thus providing an appropriate balance between good optical characteristics and a short lens length. Setting the threshold values TH _MAX and TH _MIN of FS as the Second Condition of Fig. 64 may also make it possible to provide a better balanced lens system.

Conditions regarding other parameters shown in Fig. 64 also affect the aberration characteristics. For example, if TTL/F falls below the threshold value TH _MIN, the entire length of the lens system becomes too short with respect to the focal length, so that the refractive power of each lens group becomes large, deteriorating various aberrations. When |Fk/F| (K=2, 3, 4) exceeds the threshold value TH _MAX, the focal length of Group k becomes too long, so that the effective diameter becomes large, which makes the entire length of the lens system longer. Similarly, for other parameters, various aberrations may be deteriorated within the range below the threshold value TH _MIN and in the range above the threshold value TH _MAX, or the lens system may be enlarged, or both may occur.

(Hardware configuration example of an imaging apparatus)

Fig. 65 shows hardware configuration of an imaging apparatus 10. Fig. 65 is a block diagram of an imaging apparatus according to the embodiment of the present disclosure.

The imaging apparatus 10 may include an optical apparatus 11, an image sensor 12, processing circuitry 13, a storage device 14 and a display 15. The optical apparatus 11 corresponds to any one of the optical apparatus 100A to 100I described above. The image sensor 12 may be a CMOS imaging sensor or a CCD image sensor. The processing circuitry 13 is a hardware element capable of processing an output signal from the image sensor 12 to generate image data. The processing circuitry 13 may be at least one CPU (Central Processing Unit) , at least one FPGA (Field-Programmable Gate Array) , at least one GPU (Graphics Processing Unit) or the like. The storage device 14 is a hardware element which may store image data, such as a SSD (Solid State Drive) , a HDD (Hard Disk Drive) , a RAM (Random Access Memory) , a ROM (Read Only Memory) , a flash memory or a memory card. The storage device 14 may also be a non-transitory computer readable removable storage medium. The display 15 is a hardware element for displaying information such as a video, an image and a text. The display 15 may be a LCD (Liquid Crystal Display) , an ELD (Electro-Luminescent Display) , or the like.

(Hardware configuration example of mobile equipment)

Fig. 66 shows the hardware configuration of mobile equipment 20. Fig. 66 is a block diagram of mobile equipment according to the embodiment of the present disclosure.

The mobile equipment 20 may include an optical apparatus 21, an image sensor 22, processing circuitry 23, a storage device 24, a display 25 and a communication unit 26.

The optical apparatus 21 corresponds to any one of the optical apparatuses 100A to 100I described above. The image sensor 22 may be a CMOS imaging sensor or a CCD image sensor. The processing circuitry 23 is a hardware element capable of processing an output signal from the image sensor 22 to generate image data. The processing circuitry 23 may be at least one CPU, at least one FPGA, at least one GPU or the like. The storage device 24 is a hardware element which may store image data, such as a SSD, a HDD, a RAM, a ROM, a flash memory or a memory card. The storage device 24 may also be a non-transitory computer readable removable storage medium. The display 25 is a hardware element for displaying information such as a video, an image and a text. The display 25 may be a LCD, an ELD or the like. The communication unit 26 is a hardware element for connecting to a wireless or cabled network, and may be used to post information such as a video, an image and a text to an SNS (Social Networking Service) and to upload such information to a cloud storage.

The foregoing disclosure merely discloses exemplary embodiments, and is not intended to limit the protection scope of the present invention. It will be appreciated by those skilled in the art that the foregoing embodiments and all or some of other embodiments and modifications which may be derived based on the scope of claims of the present invention will of course fall within the scope of the present invention.

Claims

An optical apparatus comprising:

first to fourth lens groups each including one or more lenses, wherein the first lens group includes a bending optical element, wherein at least one lens or lens group in the second to fourth lens groups is moved for focusing, and a parameter FS related to focusing sensitivity is expressed by Equation (1) :

and the parameter FS satisfies a condition of Equation (2) :

FS<4 ... Eq. (2) ,

where M _f indicates lateral magnification of the at least one lens or lens group and M _i (i=m, ..., n) indicates lateral magnification of an i-th lens located on an image side of the at least one lens or lens group.
The optical apparatus according to claim 1, wherein the parameter FS further satisfies a condition of Equation (2a) :

FS>0.5 ... Eq. (2a) .
The optical apparatus according to claim 2, wherein the parameter FS further satisfies a condition of Equation (2b) :

0.9<FS<3.95 ... Eq. (2b) .
The optical apparatus according to any one of claims 1 to 3, wherein a total lens length TTL of an entire lens system including the first to fourth lens groups satisfies a condition of Equation (3) :

TTL/F>0.7 ... Eq. (3) ,

where F indicates a focal length of the entire lens system.
The optical apparatus according to claim 4, wherein the total lens length TTL of the entire lens system further satisfies a condition of Equation (3a) :

1.0<TTL/F<3.5 ... Eq. (3a) .
The optical apparatus according to any one of claims 1 to 5, wherein a focal length F2 of the second lens group satisfies a condition of Equation (4) :

|F2/F|<6.0 ... Eq. (4) ,

where F indicates a focal length of the entire lens system.
The optical apparatus according to claim 6, wherein the focal length F2 of the second lens group further satisfies a condition of Equation (4a) :

0.5<|F2/F|<5.7 ... Eq. (4a) .
The optical apparatus according to any one of claims 1 to 7, wherein a focal length F3 of the third lens group satisfies a condition of Equation (5) :

|F3/F|<1.2 ... Eq. (5) ,

where F indicates a focal length of the entire lens system.
The optical apparatus according to claim 8, wherein the focal length F3 of the third lens group satisfies a condition of Equation (5a) :

0.1<|F3/F|<1.1 ... Eq. (5a) .
The optical apparatus according to any one of claims 1 to 9, wherein a focal length F4 of the fourth lens group satisfies a condition of Equation (6) :

|F4/F|<4.5 ... Eq. (6) ,

where F indicates a focal length of the entire lens system.
The optical apparatus according to claim 10, wherein the focal length F4 of the fourth lens group satisfies a condition of Equation (6a) :

0.3<|F4/F|<4.4 ... Eq. (6a) .
The optical apparatus according to any one of claims 1 to 11, wherein a focal length F1 of the first lens group and a focal length F2 of the second lens group satisfy a condition of Equation (7) :

|F1/F2|<7.5 ... Eq. (7) .
The optical apparatus according to claim 12, wherein the focal length F1 of the first lens group and the focal length F2 of the second lens group further satisfy a condition of Equation (7a) :

0.25<|F1/F2|<7.3 ... Eq. (7a) .
The optical apparatus according to any one of claims 1 to 13, wherein a focal length F2 of the second lens group and a focal length F3 of the third lens group satisfy a condition of Equation (8) :

|F2/F3|<10.0 ... Eq. (8) .
The optical apparatus according to claim 14, wherein the focal length F2 of the second lens group and the focal length F3 of the third lens group further satisfy a condition of Equation (8a) :

0.5<|F2/F3|<9.8 ... Eq. (8a) .
The optical apparatus according to any one of claims 1 to 15, wherein Abbe's number v _f of at least one focusing lens or focusing lens group satisfies a condition of Equation (9) :

v _f>16 ... Eq. (9) .
The optical apparatus according to claim 16, wherein the Abbe's number v _f of at least one focusing lens or focusing lens group further satisfies a condition of Equation (9a) :

25<v _f<58 ... Eq. (9a) .
The optical apparatus according to claim 16 or 17, wherein if a plurality of lenses are moved for the focusing, the Abbe's number v _f is an average of Abbe's numbers of the plurality of lenses.
The optical apparatus according to any one of claims 1 to 17, wherein the at least one lens or lens group which is a focusing lens or group is moved along a direction perpendicular to an optical axis of the at least one lens or lens group which is a focusing lens or group for optical image stabilization.
The optical apparatus according to any one of claims 1 to 19, wherein the first lens group includes one or more lenses located on an object side of the bending optical element.
The optical apparatus according to any one of claims 1 to 20, wherein the first lens group has positive refractive power, the second lens group has positive refractive power, the third lens group has negative refractive power and the fourth lens group has positive refractive power.
The optical apparatus according to any one of claims 1 to 20, wherein the first lens group has positive refractive power, the second lens group has negative refractive power, the third lens group has positive refractive power and the fourth lens group has positive refractive power.
The optical apparatus according to any one of claims 1 to 20, wherein the first lens group has negative refractive power, the second lens group has positive refractive power, the third lens group has negative refractive power and the fourth lens group has positive refractive power.
The optical apparatus according to any one of claims 1 to 20, wherein the first lens group has negative refractive power, the second lens group has positive refractive power, the third lens group has positive refractive power and the fourth lens group has negative refractive power.
The optical apparatus according to any one of claims 1 to 20, wherein the first lens group has positive refractive power, the second lens group has negative refractive power, the third lens group has positive refractive power and the fourth lens group has negative refractive power.
The optical apparatus according to any one of claims 1 to 25, further comprising: an actuator configured to move the at least one lens or lens group for at least one of automatic focusing and optical image stabilization.
An imaging apparatus comprising: the optical apparatus according to any one of claims 1 to 26, and an imaging sensor for generating imaging data based on incident light through the optical apparatus.
Mobile equipment with an imaging function, comprising: the optical apparatus according to any one of claims 1 to 26, and an imaging sensor for generating imaging data based on incident light through the optical apparatus.