WO2023087146A1

WO2023087146A1 - Imaging lens assembly, camera module and imaging device

Info

Publication number: WO2023087146A1
Application number: PCT/CN2021/130973
Authority: WO
Inventors: Tatsuya Nakatsuji; Yoji Okazaki; Takashi Hashimoto
Original assignee: Guangdong Oppo Mobile Telecommunications Corp., Ltd.
Priority date: 2021-11-16
Filing date: 2021-11-16
Publication date: 2023-05-25

Abstract

An imaging lens assembly includes a first optical system including a first lens group for shooting at a first angle of view, the first optical system being configured to bend an optical path of light, which is emitted from the first lens group, toward an imaging surface side, and a second optical system including a second lens group for shooting at a second angle of view smaller than the first angle of view, the shooting at the second angle of view being performed at a focal lengthwhich is different from that of the shooting at the first angle of view.

Description

IMAGING LENS ASSEMBLY, CAMERA MODULE AND IMAGING DEVICE

TECHNICAL FIELD

The present disclosure relates to an imaging lens assembly, a camera module, and an imaging device, and more specifically, to an imaging lens assembly, a camera module, and an imaging device that are slim and enable good optical performance.

BACKGROUND

In recent years, portable imaging devices such as mobile phones and digital cameras are being widely used. With the recent miniaturization of imaging devices, the imaging lens assembly mounted on the imaging devices also requires to be miniaturized. In order to meet such a demand for miniaturization, the focal length of the conventional imaging lens assembly is secured within a restricted space by disposing a prism on the object side of a lens group.

However, with the conventional imaging lens assembly, it is difficult to perform shooting at different focal lengths with a simple and compact configuration.

SUMMARY

The present disclosure aims to solve at least one of the technical problems mentioned above. Accordingly, the present disclosure needs to provide an imaging lens, a camera module and an imaging device.

In accordance with the present disclosure, an imaging lens assembly includes:

a first optical system including a first lens group for shooting at a first angle of view, the first optical system being configured to bend an optical path of light, which is emitted from the first lens group, toward an imaging surface side; and

a second optical system comprising a second lens group for shooting at a second angle of view smaller than the first angle of view, the shooting at the second angle of view being performed at a focal length which is different from that of the shooting at the first angle of view.

In accordance with the present disclosure, a camera module includes:

the imaging lens assembly; and

an image sensor including the imaging surface.

In accordance with the present disclosure, an imaging device includes:

the camera module; and

a housing which houses the camera module.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of embodiments of the present disclosure will become apparent and more readily appreciated from the following descriptions made with reference to the drawings, in which:

FIG. 1A is a diagram of an imaging device according to the present disclosure illustrating an example of a camera module when shooting is performed with a first lens group;

FIG. 1B is a perspective view of the camera module shown in FIG. 1A;

FIG. 2A is a diagram of an imaging device according to the present disclosure illustrating an example of a camera module when shooting is performed with a second lens group;

FIG. 2B is a perspective view of the camera module shown in FIG. 2A;

FIG. 3A is a diagram of an imaging device according to the present disclosure illustrating another example of the camera module when shooting is performed with the first lens group;

FIG. 3B is a diagram of an imaging device according to the present disclosure illustrating another example of the camera module when shooting is performed with the second lens group;

FIG. 4 is an explanatory diagram for explaining lens parameters of the imaging lens assembly according to the present disclosure;

FIG. 5A is a diagram of a camera module when shooting is performed with the first lens group according to a first example of the present disclosure;

FIG. 5B is a diagram of a camera module when shooting is performed with the second lens group according to the first example of the present disclosure;

FIG. 6 is an aberration diagram of the camera module when shooting is performed with the first lens group according to the first example of the present disclosure;

FIG. 7 is an aberration diagram of the camera module when shooting is performed with the second lens group according to the first example of the present disclosure;

FIG. 8A is a diagram of a camera module when shooting is performed with the first lens group according to a second example of the present disclosure;

FIG. 8B is a diagram of a camera module when shooting is performed with the second lens group according to the second example of the present disclosure;

FIG. 9 is an aberration diagram of the camera module when shooting is performed with the first lens group according to the second example of the present disclosure;

FIG. 10 is an aberration diagram of the camera module when shooting is performed with the second lens group according to the second example of the present disclosure;

FIG. 11A is a diagram of a camera module when shooting is performed with the first lens group according to a third example of the present disclosure;

FIG. 11B is a diagram of a camera module when shooting is performed with the second lens group according to the third example of the present disclosure;

FIG. 12 is an aberration diagram of the camera module when shooting is performed with the first lens group according to the third example of the present disclosure;

FIG. 13 is an aberration diagram of the camera module when shooting is performed with the second lens group according to the third example of the present disclosure;

FIG. 14A is a plan view of an imaging device when shooting is performed with the first lens group according to the fourth example of the present disclosure, and

FIG. 14B is a plan view of an imaging device when shooting is performed with the second lens group according to the fourth example of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described in detail and examples of the embodiments will be illustrated in the accompanying drawings. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions. The embodiments described herein with reference to the drawings are explanatory and aim to illustrate the present disclosure, but shall not be construed to limit the present disclosure.

First, the outline of the present disclosure will be described. As shown in FIGS. 1A to 2B, an imaging device 1 to which the present disclosure applies includes a camera module 11, a housing 12 for housing the camera module 11, and a mirror drive mechanism 13. The size of the housing 12 shown in FIGS. 1A and 2A may differ from the size of the housing of the actual imaging device. The camera module 11, to which the present disclosure more specifically applies, is configured as shown in FIGS. 5A, 5B, 8A, 8B, 11A, and 11B, for example.

The camera module 11 includes an imaging lens assembly 21, an optical filter 22, and an image sensor 23 having an imaging surface S.

The imaging lens assembly 21 includes a plurality of optical systems having different focal lengths (i.e., different angles of view) . Specifically, the imaging lens assembly 21 includes a first optical system 211 which performs shooting at a first angle of view, and a second optical system 212 which performs shooting at a second angle of view smaller than the first angle of view. The shooting at the second angle of view is performed at a focal length which is different from that of the shooting at the first angle of view. For example, the shooting at the first angle of view is wide-angle shooting at a short focal length. The shooting at the second angle of view is telephoto shooting at a long focal length.

The first optical system 211 includes a first lens group 331 for shooting at the first angle of view. The first optical system 211 is a periscope type optical system configured to bend an optical path of light, which is emitted from the first lens group 331, toward the imaging surface S side. More specifically, the first optical system 211 includes, in order from an object side, a first reflective member 311, a first aperture stop 321, a first lens group 331, and a mirror 341.

The second optical system 212 includes a second lens group 332 for shooting at the second angle of view smaller than the first angle of view, the shooting at the second angle of view being performed at the focal length which is different from that of the shooting at the first angle of view. The second optical system 212 is a periscope type optical system configured to bend an optical path of light, which is emitted from the second lens group 332, toward the imaging surface S side. More specifically, the second optical system 212 includes, in order from the object side, a second reflective member 312, a second aperture stop 322, a second lens group 332, and a third reflective member 342.

The second lens group 322 is disposed farther from the imaging surface S than the first lens group 331. In FIGS. 1A and 2A, dash–dot lines represent the optical axis of the imaging lens assembly 21 (hereinafter the same applies) .

As shown in FIGS. 1A and 2A, the optical axes of the imaging lens assembly 21 includes a first optical axis OA1 which is an optical axis of the first optical system 211, and a second optical axis OA2 which is an optical axis of the second optical system 212. The first optical axis OA1 includes an optical axis OA11 of the first lens group 331 and, between the mirror 341 and the imaging surface S, a bent portion OA12. The optical axis OA11 of the first lens group 331 and the bent portion OA12 are continuous with each other at an intersection 341b with the mirror 341. The second optical axis OA2 includes an optical axis OA21 of the second lens group 332 and a bent portion OA22 between the third reflective member 342 and the imaging surface S. The optical axis OA21 of the second lens group 332 and the bent portion OA22 are continuous with each other at an intersection 342b with the third reflective member 342.

In the examples shown in FIGS. 1A to 2B, the optical axis OA11 of the first lens group 331 and the optical axis OA21 of the second lens group 332 are substantially parallel to each other. Further, the bent portion OA12 of the first optical axis OA1 and the bent portion OA22 of the second optical axis OA2 are substantially parallel to each other and substantially perpendicular to the imaging surface S. Further, the optical axes OA1 and OA2 of the imaging lens assembly 21 are perpendicular to a thickness direction of the imaging device 1 (i.e., a thickness direction of the housing 12) .

As shown in FIG. 1B, the first reflective member 311 has a reflective surface 311a that reflects light L1, which is incident from the object side, toward the first lens group 331 side. The first reflective member 311 is, for example, a prism which totally reflects light, which is internally incident on the reflective surface 311a from the object side, to the first lens group 331 side. By adopting a prism, the first reflective member 311 can be easily configured. The first reflective member 311 can also be easily configured by adopting a mirror.

The first lens group 331 is housed in a single barrel (see reference numeral 3311 in FIGS. 14A and 14B) . The first lens group 331 includes at least a most object side disposed lens and a most imaging surface S side disposed lens. The number of lenses included in the first lens group 331 is preferably between 4 or more and 7 or less. By setting the number of lenses included in the first lens group 331 to be between 4 or more and 7 or less, it is possible to sufficiently correct various aberrations without disposing additional lenses on the imaging surface S side of the mirror 341, when shooting with the first lens group 331 is performed.

The mirror 341 is disposed between the first lens group 331 and the imaging surface S. As shown in FIGS. 1A and 1B, the mirror 341 is configured to reflect incident light, which is incident from the first lens group 331, toward the imaging surface S by tilting with respect to the optical axis OA11 of the first lens group 331 when shooting (recording as an image) of a subject (object) is performed with the first lens group 331 (i.e., when wide-angle shooting at a short focal length is performed) . In the example shown in FIG. 1A, the imaging surface S is substantially parallel to the optical axis OA11 of the first lens group 331 (i.e., substantially perpendicular to a reflection direction of the incident light on the mirror 341) .

On the other hand, as shown in FIGS. 2A and 2B, the mirror 341 is configured to be substantially perpendicular (i.e., 90°) to the optical axis OA11 of the first lens group 331 when shooting of the subject is performed with the second lens group 332 (i.e., when telephoto shooting at a long focal length is performed) . Specifically, in the examples shown in FIGS. 1A and 2A, the mirror 341 can change its angle θ with respect to the optical axis OA11 of the first lens group 331 by rotating about a rotation axis 341a located on one end side of the imaging surface S side of the mirror 341. Further, the mirror 341 can be rotated by the mirror drive mechanism 13 which is a part of the imaging device 1.

The mirror 341 can be easily manufactured, for example, by coating a substrate containing at least one of glass and plastic, with a reflective film containing a metal such as aluminum.

The mirror drive mechanism 13 may include, for example, an elastic member (for example, a spring) which applies to the mirror 341 an elastic force in a direction in which the mirror 341 tilts with respect to the optical axis OA11 of the first lens group 331, and an actuator capable of pushing the mirror 341 back against the elastic force of the elastic member in a direction in which the mirror 341 is perpendicular to the optical axis OA11.

As shown in FIG. 2B, the second reflective member 312 has a reflective surface 312a that reflects light L2, which is incident from the object side, toward the second lens group 332 side. The second reflective member 312 is, for example, a prism which totally reflects light, which is internally incident on the reflective surface 312a from the object side, to the second lens group 332 side. By adopting a prism, the second reflective member 312 can be easily configured. The second reflective member 312 can also be easily configured by adopting a mirror.

The second lens group 332 is housed in a single barrel (see reference numeral 3321 in FIGS. 14A and 14B) . The second lens group 332 includes at least a most object side disposed lens and a most imaging surface S side disposed lens. The number of lenses included in the second lens group 332 is preferably between 4 or more and 7 or less. By setting the number of lenses included in the second lens group 332 to be between 4 or more and 7 or less, it is possible to sufficiently correct various aberrations without disposing an additional lens on the imaging surface S side of the mirror 341, when shooting with the second lens group 332 is performed.

The third reflective member 342 is disposed between the second lens group 332 and the imaging surface S. More specifically, the third reflective member 342 is disposed on the optical axis OA21 of the second lens group 332. The third reflective member 342 has a reflective surface 342a that reflects light, which is incident from the second lens group 332, toward the imaging surface S. The third reflective member 342 is, for example, a prism which totally reflects light, which is internally incident on the reflective surface 342a from the second lens group 332, toward the imaging surface S. By adopting a prism, the third reflective member 342 can be easily configured. The third reflective member 342 can also be easily configured by adopting a mirror.

The imaging device 1 is switched from a shooting state with the second lens group 332 (i.e., telephoto shooting state at a long focal length) to a shooting state with the first lens group 331 (i.e., wide-angle shooting state at a short focal length) when a user operation for switching from the shooting state with the second lens group 332 to the shooting state with the first lens group 331 is performed in the shooting state with the second lens group 332. The imaging device 1 is also switched from the shooting state with the second lens group 332 to the shooting state with the first lens group 331 when an automatic operation which is implemented using an algorithm, such as scene detection, is performed in the shooting state with the second lens group 332.

During the switching from the shooting state with the second lens group 332 to the shooting state with the first lens group 331, the imaging device 1 rotates the mirror 341 toward the first lens group 331 and tilts the mirror 341 with respect to the optical axis OA11 of the first lens group 331 by using the mirror drive mechanism 13. A tilt angle θ of the mirror 341 is preferably 42° or more and 48° or less, and more preferably 45°. By having the tilt angle θ in such a preferable range, the mirror 341 can reflect incident light, which is incident from the first lens group 331, in a direction substantially perpendicular to the optical axis OA11 of the first lens group 331 in the shooting state with the first lens group 331. That is, the mirror 341 can bend an optical path substantially 90°. As a result, it is possible to prevent the imaging device 1 from being large in the direction perpendicular to the thickness direction.

On the other hand, the imaging device 1 is switched from the shooting state with the first lens group 331 to the shooting state with the second lens group 332 when a user operation for switching from the shooting state with the first lens group 331 to the shooting state with the second lens group 332 is performed in the shooting state with the first lens group 331. The imaging device 1 is also switched from the shooting state with the first lens group 331 to the shooting state with the second lens group 332 when an automatic operation which is implemented using an algorithm, such as scene detection, is performed in the shooting state with the first lens group 331.

During the switching from the shooting state with the first lens group 331 to the shooting state with the second lens group 332, the imaging device 1 rotates the mirror 341 in the direction away from the first lens group 331 until the mirror 341 is substantially perpendicular to the optical axis OA11 of the first lens group 331 by using the mirror drive mechanism 13. As a result, it is possible to prevent the mirror 341 from obstructing an optical path connecting the second lens group 332 and the imaging surface S in the shooting state with the second lens group 332. That is, the mirror 341 is configured to cause light, which is emitted from the second lens group 332, to fall incident on the imaging surface S by being substantially perpendicular to the optical axis OA11 of the first lens group 331 when shooting with the second lens group 331 is performed.

In the shooting state with the second lens group 332, the third reflective member 342 reflects incident light from the second lens group 332 toward the imaging surface S. A tilt angle of the reflective surface 342a of the third reflective member 342 with respect to the optical axis OA21 of the second lens group 332 is preferably the same as the tilt angle θ of the mirror 341 with respect to the optical axis OA11 of the first lens group 331. As a result, since a reflection direction of the third reflective member 342 can be aligned with a reflection direction of the mirror 341, the shooting with the first lens group 331 and the shooting with the second lens group 332 can be properly performed by both using the image sensor 23.

The image sensor 23 is, for example, a solid-state image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) or a CCD (Charge Coupled Device) . The image sensor 23 has the imaging surface S which is an imaging plane of the imaging lens assembly 21. The image sensor 23 receives incident light from the subject (object side) via the imaging lens assembly 21 and the optical filter 22, photoelectrically converts the light, and outputs an image data, obtained by photoelectric conversion of the light, to a subsequent stage. The optical filter 22 disposed between the imaging lens assembly 21 and the image sensor 23 may be, for example, an IR (infrared) filter which cuts infrared light from incident light.

According to the imaging device 1 configured as described above, the image sensor 23 can be used by both the first optical system 211 and the second optical system 212 by disposing the mirror 341, which is capable of switching the optical path, between the first lens group 331 and the imaging surface S. As a result, the number of parts can be reduced while ensuring a degree of freedom in the focal length. Therefore, according to the present disclosure, it is possible to perform shooting at different focal lengths with a simple and compact configuration. Further, since the image sensor 23 can be shared, it is possible to adopt a large image sensor 23 such as a 1 /1.56 type sensor while suppressing the size of the entire imaging device 1.

Further, according to the present disclosure, since the imaging lens assembly 21 is disposed so that the first optical axis OA1 and the second optical axis OA2 are perpendicular to the thickness direction of the imaging device 1, shooting at different focal lengths can be performed with a slim imaging device 1.

Further, according to the present disclosure, since all the lenses for the wide-angle shooting at the short focal length are disposed on the object side of the mirror 341, deterioration of optical performance due to eccentricity of the lenses during the wide-angle shooting can be suppressed. Further, since all the lenses for the telephoto shooting at the long focal length are disposed on the object side of the mirror 341, it is possible to suppress deterioration of optical performance due to eccentricity of the lenses during the telephoto shooting.

Further, according to the imaging device 1 in which the optical axis OA11 of the first lens group 331 and the optical axis OA21 of the second lens group 332 are substantially parallel to each other and the third reflective member 342 is provided as shown in FIGS. 1A and 2A, orientation of an image of the subject to be imaged on the imaging surface S can be aligned between the wide-angle shooting and the telephoto shooting. As a result, it is not necessary to perform image processing for aligning the orientation of the image of the subject between the wide-angle shooting and the telephoto shooting.

The camera module 11 according to the present disclosure may be configured as shown in FIGS. 3A and 3B. Unlike the camera module 11 shown in FIGS. 1A to 2B, the camera module 11 shown in FIGS. 3A and 3B does not include the third reflective member 342 and includes an image sensor 23 on the optical axis OA 21 of the second lens group 332. Since the third reflective member 342 is not provided, the camera module 11 shown in FIGS. 3A and 3B does not have the bent portion OA22 of the second optical axis OA2 shown in FIG. 2A. That is, in the camera module 11 shown in FIGS. 3A and 3B, the optical axis OA21 itself of the second lens group 332 is the second optical axis OA2. Further, the optical axis OA11 of the first lens group 331 and the optical axis OA21 of the second lens group 332 are substantially perpendicular to each other.

According to the camera module 11 shown in FIGS. 3A and 3B, the third reflective member 342 can be omitted, thereby the number of parts can be further reduced.

The manufacturability of the imaging lens assembly 21 to which the present disclosure applies can be secured when the imaging lens assembly 21 satisfies the following formula (1) :

BFL2 /BFL1> 1.2 (1)

In the formula (1) , BF1 is a distance on the first optical axis OA1 from a surface on the imaging surface S side of the most imaging surface S side disposed lens of the first lens group 331 to the imaging surface S (hereinafter the same applies) . BFL1 can also be said to be a back focus of the first lens group 331. BF2 is a distance on the second optical axis OA2 from a surface on the imaging surface S side of a most imaging surface S side disposed lens of the second lens group 332 to the imaging surface S (hereinafter the same applies) . BFL2 can also be said to be a back focus of the second lens group 332.

If the value of BFL2 /BFL1 falls below the lower limit of the formula (1) , it is difficult to dispose the third reflective member 342 and the mirror 341 between the second lens group 332 and the imaging surface S, and the manufacturability of the imaging lens assembly 21 declines.

Further, the manufacturability of the imaging lens assembly 21 to which the present disclosure applies can be secured and the miniaturization of the imaging lens assembly 21 can be more effective when the imaging lens assembly 21 satisfies the following formulas (2) and (3) :

50° > FOVm1> 26° (2)

26° > FOVm2> 10° (3)

In the formula (2) , FOVm1 is twice the value of a maximum angle formed by an incident light, which is incident on the first aperture stop 321, with respect to the optical axis OA11 of the first lens group 311 (hereinafter the same applies) . FOVm1 can also be said to be an angle of view of the first lens group 331. In the formula (3) , FOVm2 is twice the value of a maximum angle formed by an incident light, which is incident on the second aperture stop 322, with respect to the optical axis OA21 of the second lens group 322 (hereinafter the same applies) . FOVm2 can also be said to be an angle of view of the second lens group 331.

If the value of FOVm1 exceeds the upper limit value (50°) of the formula (2) , it is difficult to secure sufficient back focus for the first lens group 331, and thus the manufacturability of the imaging lens assembly 21 decreases. On the other hand, if the value of FOVm1 falls below the lower limit value (26°) of the formula (2) , the back focus of the first lens group 331 is too large, and it is difficult to miniaturize the imaging lens assembly 21. Further, if the value of FOVm2 exceeds the upper limit value (26°) of the formula (3) , it is difficult to secure sufficient back focus for the second lens group 332, and thus the manufacturability of the imaging lens assembly 21 decreases. On the other hand, if the value of FOVm2 falls below the lower limit value (10°) of the formula (3) , the back focus of the second lens group 332 is too large, and it is difficult to miniaturize the imaging lens assembly 21.

Further, the imaging lens assembly 21 to which the present disclosure applies can be further miniaturized when the imaging lens assembly 21 satisfies the following formulas (4) and (5) :

da1 <ds (4)

da2 <ds (5)

In the formula (4) , da1 is a diameter (i.e., an opening diameter) of the first aperture stop 321 (hereinafter the same applies) . ds is a short side dimension of a rectangular imaging surface S (i.e., image sensor 23) shown in FIG. 4 (hereinafter the same applies) . In the formula (5) , da2 is a diameter (i.e., an opening diameter) of the second aperture stop 322 (hereinafter the same applies) .

If da1 and da2 exceed ds, the sizes of the first reflective member 311 and the second reflective member 312 are too large, and thus the thickness of the imaging lens assembly 21 cannot be reduced and miniaturization of the imaging lens assembly 21 is difficult.

Further, in recent years, a function, which makes a subject stand out effectively by detecting a background other than an in-focus subject using AI processing and blurring an image of the background using digital processing, has been generally used. However, unlike an ordinary optical blur, all the portions other than the in-focus subject are blurred by the function, and this causes the image to look unnatural. In order to create good optical blur, it is necessary to make a depth of field shallow. In order to make the depth of field shallow, it is necessary to increase the imaging area in addition to decreasing the F number of the lens.

The imaging lens assembly 21 can effectively create good optical blur when the imaging lens assembly 21 satisfies the following formula (6) :

4.0 mm <dd (6)

In the formula (6) , dd is a half-diagonal length of the imaging surface S shown in FIG. 4 (hereinafter the same applies) .

If dd falls below the lower limit of the formula (6) , since the size of the image sensor 23 is too small, the depth of field is deep, and thus it is difficult to create good optical blur.

An aspheric lens among lenses included in the imaging lens assembly 21 can be formed of a glass material and a plastic material. However, from the viewpoint of lens molding, it is preferable that the aspheric lens is formed of a plastic material. This is because, if the aspheric lens is made of a material other than plastic, a tolerance with respect to an outer shape of the lens is large, and thus, lens eccentricity occurs and it is difficult to obtain a good image.

Such a camera module 11 including the imaging lens assembly 21 can be used in compact digital devices (imaging devices 1) such as mobile phones, wearable cameras and surveillance cameras.

Next, more specific examples to which the present disclosure applies will be described. In the following examples, “Si” indicates the ordinal number of the I-th surface which sequentially increases from the object side toward the imaging surface S side. Optical elements of the corresponding surfaces are indicated by the corresponding surface number “Si” . Denotations of “first surface” or “1st surface” indicate a surface on the object side of the lens, and denotations of “second surface” or “2nd surface” indicate a surface on the imaging surface S side of the lens. “Ri” indicates the value of a central curvature radius (mm) of the surface. “Di” indicates a value of a distance on the optical axis between the I-th surface and the (i + 1) -th surface (mm) . “Ndi” indicates a value of a refractive index at d-line (wavelength 587.6 nm) of the material of the optical element having the i-th surface. “νdi” indicates a value of the Abbe number at d-line of the material of the optical element having the i-th surface. “Material” indicates a material of the optical element having the i-th surface. "E-i" indicates an exponential expression with a base of 10, i.e., "10 ^-i" . For example, "1.767846.E-4" indicates "1.767846 × 10 ^-4" .

The imaging lens assembly 21 used in the following examples includes lenses having aspheric surfaces. The aspheric shape of the lens is defined by the following formula (7) :

Z = C × h ² / {1 + (1 -K × C ² × h ²) ^1/2} + Σ An × h ⁿ (7)

(n = an integer greater than or equal to 3) .

In the formula (7) , Z is a depth of the aspheric surface, C is a paraxial curvature which is equal to 1 /R, h is a distance from the optical axis to a lens surface, K is a conic constant (second-order aspheric coefficient) , and An is an nth-order aspheric coefficient.

[First Example]

First, a first example in which specific numerical values are applied to the camera module 11 shown in FIGS. 5A and 5B will be described.

[First optical system]

In the first example, the first optical system 211 (i.e., the optical system for wide-angle imaging) in the imaging lens assembly 21 includes, in order from the object side toward the imaging surface S side, a first prism P1 as an example of the first reflective member 311, a first aperture stop 321, a first lens L1w having a positive refractive power in a paraxial region with a convex surface facing the object side, a second lens L2w having a negative refractive power in the paraxial region, a third lens L3w having a positive refractive power in the paraxial region, a fourth lens L4w having a positive refractive power in the paraxial region with a convex surface facing the imaging surface S side, and a fifth lens L5w having a negative refractive power in the paraxial region.

Table 1 shows lens data on the side of the first optical system 211 in the first example. Table 2 shows aspheric coefficients on the side of the first optical system 211 in the first example.

TABLE 1

TABLE 2

[Second optical system]

In the first example, the second optical system 212 (i.e., the optical system for telephoto shooting) in the imaging lens assembly 21 includes, in order from the object side toward the imaging surface S side, a second prism P2 as an example of the second reflective member 312, a second aperture stop 322, a first lens L1t having a positive refractive power in a paraxial region with convex surfaces facing the object side and the imaging surface S side, a second lens L2t having a negative refractive power in the paraxial region, a third lens L3t having a negative refractive power in the paraxial region with a concave surface facing the imaging surface S side, a fourth lens L4t having a positive refractive power in the paraxial region with convex surfaces facing the object side and the imaging surface S side, and a fifth lens L5t having a negative refractive power in the paraxial region.

Table 3 shows lens data on the side of the second optical system 212 in the first example. Table 4 shows aspheric coefficients on the side of the second optical system 212 in the first example.

TABLE 3

TABLE 4

[Parameters corresponding to conditional expressions]

Table 5 shows values of parameters corresponding to the conditional expressions.

TABLE5

FOVm 1 (°)	38.399
FOVm 2 (°)	24.290
BFL1 (mm)	10.000
BFL2 (mm)	12.982
BFL2/BFL1	1.298
da1 (mm)	4.800
da2 (mm)	6.170
ds (mm)	6.264
dd (mm)	5.128

Aberrations on the side of the first optical system 211 in the first example are shown in FIG. 6. Aberrations on the side of the second optical system 212 in the first example are shown in FIG. 7. FIGS. 6 and 7 show, as examples of aberrations, spherical aberration, astigmatism (field curvature) , distortion and chromatic difference of magnification. In the graph showing astigmatism, a reference wavelength is d-line (587.56 nm) . Further, “S” indicates a value of aberration on a sagittal image surface and “T” indicates a value of aberration on a tangential image surface. In the spherical aberration diagram, aberrations with respect to g-line (435.84 nm) , d-line and C-line (656.27 nm) are shown. In the distortion diagram, a reference wavelength is d-line. In the diagram of the chromatic difference of magnification, chromatic differences of magnification of C-line and g-line when d-line is used as a reference wavelength are shown. The same applies to aberration diagrams in other examples.

As can be seen from the aberration diagrams in FIGS. 6 and 7, it is clear that the camera module 11 in the first example can satisfactorily correct various aberrations to obtain superior optical performance.

[Second Example]

Next, a second example in which specific numerical values are applied to the camera module 11 shown in FIGS. 8A and 8B will be described.

Unlike the first example, in the second example, the second optical system 212 includes a third prism P3 as an example of the third reflective member 342. The third prism P3 is disposed on the imaging surface S side of the fifth lens L5.

The lens parameters corresponding to those in the first example are shown in Tables 6 to 10.

[First optical system]

TABLE 6

TABLE 7

[Second optical system]

TABLE 8

TABLE 9

[Parameters corresponding to conditional expressions]

TABLE10

FOVm 1 (°)	38.399
FOVm 2 (°)	20.919
BFL1 (mm)	10.000
BFL2 (mm)	18.950
BFL2/BFL1	1.895
da1 (mm)	4.800
da2 (mm)	6.000
ds (mm)	6.264
dd (mm)	5.128

Aberrations on the side of the first optical system 211 in the second example are shown in FIG. 9. Aberrations on the side of the second optical system 212 in the second example are shown in FIG. 10. According to the camera module 11 of the second example, the orientation of the subject to be imaged on the imaging surface S can be aligned between the wide-angle shooting and the telephoto shooting. As a result, it is not necessary to perform image processing for aligning the orientation of the subjects when the wide-angle shooting and the telephoto shooting are performed.

[Third Example]

Next, a third example in which specific numerical values are applied to the camera module 11 shown in FIGS. 11A and 11B will be described.

The lens parameters corresponding to those in the first example are shown in Tables 11 to 15.

[First optical system]

TABLE 11

TABLE 12

[Second optical system]

TABLE 13

TABLE 14

[Parameters corresponding to conditional expressions]

TABLE15

FOVm 1 (°)	33.576
FOVm 2 (°)	17.367
BFL1 (mm)	10.021
BFL2 (mm)	20.829
BFL2/BFL1	2.079
da1 (mm)	5.500
da2 (mm)	6.000
ds (mm)	6.264
dd (mm)	5.128

Aberrations on the side of the first optical system 211 in the third example are shown in FIG. 12. Aberrations on the side of the second optical system 212 in the third example are shown in FIG. 13. According to the third example, by making the lens parameters different from those of the first example, the degree of freedom in designing the camera module 11 according to the present disclosure can be further increased while obtaining the same effects as in the first example.

[Fourth Example]

Next, as a fourth example, an example of the imaging device 1 provided with the mirror drive mechanism 13 in which a required fluctuation amount for driving the mirror 341 is suppressed will be described.

As shown in FIGS. 14A and 14B, in the fourth example, the mirror drive mechanism 13 includes a spring 130, a motor 131, a lead screw assembly 132, a roller 133, and a cam pin 134.

The spring 130 applies an elastic force to the mirror 341 in a direction in which the mirror 341 tilts with respect to the optical axis OA11 of the first lens group 331. The spring 130 is, for example, a torsion coil spring. The spring 130 is fixed to a support shaft 136 which rotatably supports the mirror 341. The support shaft 136 is an example of a rotation axis of the mirror 341. One end of the spring 130 is fixed to a cam pin 134 provided on the mirror 341.

The cam pin 134 extends along the thickness direction of the imaging device 1 and is inserted into a cam groove 121a. The cam groove 121a is provided in a box-shaped holder 121 which holds a part of the camera module 11 in the housing 12. The cam groove 121a has an arc shape which is concentric with the support shaft 136. Of the elements of the camera module 11, the first lens group 331, the second lens group 332, the third reflective member 342, the mirror 341, the optical filter 22, and the image sensor 23 are held in the holder 121. The other end of the spring 130 is fixed to the holder 121. Such a spring 130 can apply to the mirror 341 a counterclockwise rotational force indicated by the arrow A2 in FIG. 14B.

The motor 131 is disposed on a side of the mirror 341 which is on the opposite side of the first lens group 331 and the second lens group 332. An output axis of the motor 131 is perpendicular to the optical axis directions of the first lens group 331 and the second lens group 332 and the thickness direction of the imaging device 1. The motor 131 is, for example, a stepping motor. By adopting the stepping motor, the mirror 341 can be driven quickly with a sufficient driving force.

The lead screw assembly 132 has a screw 1321 provided on the output axis of the motor 131 and a nut 1322 that meshes with the screw 1321. The nut 1322 is provided on the outer periphery of the screw 1321 in a state where rotation of the nut 1322 in a rotation direction of the motor 131 (i.e., a rotation direction of the screw 1321) is restricted. Therefore, when the screw 1321 rotates, the nut 1322 does not rotate and performs a linear motion along an axial direction of the screw 1321. By performing the linear motion, the nut 1322 can approach, or distance from, one end 341c on the support shaft 136 side of the mirror 341.

The roller 133 is fixed to the nut 1322 so as to face the mirror 341. The roller 133 is rotatably supported by the nut 1322 so as to be rotatable about a rotation axis along the thickness direction of the imaging device 1. The roller 133 makes a linear motion integrally with the nut 1322. By performing the linear motion, the roller 133 can come into contact with or apart from the one end 341c of the mirror 341. The roller 133 can apply to the mirror 341 a clockwise rotational force indicated by an arrow A1 in FIG. 14A, when the roller 133 moves in a direction of contact with the one end 341c of the mirror 341 and continues to move in the same direction even after contacting the one end 341c.

In the mirror drive mechanism 13 configured as described above, when the motor 131 is rotated in one direction (for example, forward rotation) in the shooting state with the first lens group 331 shown in FIG. 14A, the rotation of the motor 131 is transmitted to the screw 1321 of the lead screw assembly 132, and the screw 1321 rotates. As the screw 1321 rotates, the nut 1322 of the lead screw assembly 132, which meshes with the screw 1321, linearly moves in a mirror driving direction indicated by an arrow A3 in FIG. 14A. As the nut 1322 moves linearly in the mirror driving direction, the roller 133 fixed to the nut 1322 comes into contact with the one end 314c of the mirror 341 and pushes the one end 314c in the mirror driving direction.

As a result, the mirror 341 rotates clockwise A1 against the elastic force of the spring 130. By rotating clockwise A1, the mirror 341 becomes substantially perpendicular to the optical axis OA11 of the first lens group 331. As a result, as shown in FIG. 14B, the imaging device 1 can switch from the shooting state with the first lens group 331 to the shooting state with the second lens group 332.

On the other hand, when the motor 131 is rotated in the other direction (for example, reverse rotation) in the shooting state with the second lens group 332, the rotation of the motor 131 is transmitted to the lead screw assembly 132, and the nut 1322 moves linearly in a retracting direction indicated by an arrow A4 in FIG. 14B. As the nut 1322 moves linearly in the retracting direction, the roller 133 fixed to the nut 1322 is distanced from the one end 314c of the mirror 341. As a result, the mirror 341 is rotated counterclockwise by the elastic force of the spring 130. By rotating counterclockwise, the mirror 341 is tilted with respect to the optical axis OA11 of the first lens group 331. As a result, the imaging device 1 can switch from the shooting state with second lens group 332 to the shooting state with the first lens group 331.

According to such a mirror drive mechanism 13, the roller 133 fixed to the lead screw assembly 132 can be quickly brought into contact with or distanced from the mirror 341 with a small amount of fluctuation, and thus the mirror 341 can be driven quickly. As a result, it is possible to switch between the shooting state with the first lens group 331 and the shooting state with second lens group 332 at high speed. If the diameter of the screw 1321 is increased and the length of the screw 1321 is shortened, even faster switching is possible.

Further, by making the output axis of the motor 131 perpendicular to the thickness direction of the imaging device 1, the thickness of the imaging device 1 can be suppressed.

The mirror drive mechanism 13, in which the required fluctuation amount for driving the mirror 341 is suppressed, is not limited to the configuration shown in FIGS. 14A and 14B.

In the description of embodiments of the present disclosure, it is to be understood that terms such as "central" , "longitudinal" , "transverse" , "length" , "width" , "thickness" , "upper" , "lower" , "front" , "rear" , "left" , "right" , "vertical" , "horizontal" , "top" , "bottom" , "inner" , "outer" , "clockwise" and "counterclockwise" should be construed to refer to the orientation or the position as described or as shown in the drawings under discussion. These relative terms are only used to simplify description of the present disclosure, and do not indicate or imply that the device or element referred to must have a particular orientation, or constructed or operated in a particular orientation. Thus, these terms cannot be constructed to limit the present disclosure.

In addition, terms such as "first" and "second" are used herein for purposes of description and are not intended to indicate or imply relative importance or significance or to imply the number of indicated technical features. Thus, the feature defined with "first" and "second" may comprise one or more of this feature. In the description of the present disclosure, "a plurality of" means two or more than two, unless specified otherwise.

In the description of embodiments of the present disclosure, unless specified or limited otherwise, the terms "mounted" , "connected" , "coupled" and the like are used broadly, and may be, for example, fixed connections, detachable connections, or integral connections; may also be mechanical or electrical connections; may also be direct connections or indirect connections via intervening structures; may also be inner communications of two elements, which can be understood by those skilled in the art according to specific situations.

In the embodiments of the present disclosure, unless specified or limited otherwise, a structure in which a first feature is "on" or "below" a second feature may include an embodiment in which the first feature is in direct contact with the second feature, and may also include an embodiment in which the first feature and the second feature are not in direct contact with each other, but are contacted via an additional feature formed therebetween. Furthermore, a first feature "on" , "above" or "on top of" a second feature may include an embodiment in which the first feature is right or obliquely "on" , "above" or "on top of" the second feature, or just means that the first feature is at a height higher than that of the second feature; while a first feature "below" , "under" or "on bottom of" a second feature may include an embodiment in which the first feature is right or obliquely "below" , "under" or "on bottom of" the second feature, or just means that the first feature is at a height lower than that of the second feature.

Various embodiments and examples are provided in the above description to implement different structures of the present disclosure. In order to simplify the present disclosure, certain elements and settings are described in the above. However, these elements and settings are only by way of example and are not intended to limit the present disclosure. In addition, reference numbers and/or reference letters may be repeated in different examples in the present disclosure. This repetition is for the purpose of simplification and clarity and does not refer to relations between different embodiments and/or settings. Furthermore, examples of different processes and materials are provided in the present disclosure. However, it would be appreciated by those skilled in the art that other processes and/or materials may be also applied.

Reference throughout this specification to "an embodiment" , "some embodiments" , "an exemplary embodiment" , "an example" , "aspecific example" or "some examples" means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, the appearances of the above phrases throughout this specification are not necessarily referring to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

Any process or method described in a flow chart or described herein in other ways may be understood to include one or more modules, segments or portions of codes of executable instructions for achieving specific logical functions or steps in the process, and the scope of a preferred embodiment of the present disclosure includes other implementations, in which it should be understood by those skilled in the art that functions may be implemented in a sequence other than the sequences shown or discussed, including in a substantially identical sequence or in an opposite sequence.

The logic and/or step described in other manners herein or shown in the flow chart, for example, a particular sequence table of executable instructions for realizing the logical function, may be specifically achieved in any computer readable medium to be used by the instruction execution system, device or equipment (such as the system based on computers, the system comprising processors or other systems capable of obtaining the instruction from the instruction execution system, device and equipment and executing the instruction) , or to be used in combination with the instruction execution system, device and equipment. As to the specification, "the computer readable medium" may be any device adaptive for including, storing, communicating, propagating or transferring programs to be used by or in combination with the instruction execution system, device or equipment. More specific examples of the computer readable medium comprise but are not limited to: an electronic connection (an electronic device) with one or more wires, a portable computer enclosure (a magnetic device) , a random access memory (RAM) , a read only memory (ROM) , an erasable programmable read-only memory (EPROM or a flash memory) , an optical fiber device and a portable compact disk read-only memory (CDROM) . In addition, the computer readable medium may even be a paper or other appropriate medium capable of printing programs thereon, this is because, for example, the paper or other appropriate medium may be optically scanned and then edited, decrypted or processed with other appropriate methods when necessary to obtain the programs in an electric manner, and then the programs may be stored in the computer memories.

It should be understood that each part of the present disclosure may be realized by the hardware, software, firmware or their combination. In the above embodiments, a plurality of steps or methods may be realized by the software or firmware stored in the memory and executed by the appropriate instruction execution system. For example, if it is realized by the hardware, likewise in another embodiment, the steps or methods may be realized by one or a combination of the following techniques known in the art: a discrete logic circuit having a logic gate circuit for realizing a logic function of a data signal, an application-specific integrated circuit having an appropriate combination logic gate circuit, a programmable gate array (PGA) , a field programmable gate array (FPGA) , etc.

Those skilled in the art shall understand that all or parts of the steps in the above exemplifying method of the present disclosure may be achieved by commanding the related hardware with programs. The programs may be stored in a computer readable storage medium, and the programs comprise one or a combination of the steps in the method embodiments of the present disclosure when run on a computer.

In addition, each function cell of the embodiments of the present disclosure may be integrated in a processing module, or these cells may be separate physical existence, or two or more cells are integrated in a processing module. The integrated module may be realized in a form of hardware or in a form of software function modules. When the integrated module is realized in a form of software function module and is sold or used as a standalone product, the integrated module may be stored in a computer readable storage medium.

The storage medium mentioned above may be read-only memories, magnetic disks, CD, etc.

Although embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that the embodiments are explanatory and cannot be construed to limit the present disclosure, and changes, modifications, alternatives and variations can be made in the embodiments without departing from the scope of the present disclosure.

Claims

An imaging lens assembly, comprising:

a first optical system comprising a first lens group for shooting at a first angle of view, the first optical system being configured to bend an optical path of light, which is emitted from the first lens group, toward an imaging surface side; and

a second optical system comprising a second lens group for shooting at a second angle of view smaller than the first angle of view, the shooting at the second angle of view being performed at a focal length which is different from that of the shooting at the first angle of view.
The imaging lens assembly according to claim 1, wherein

the first optical system comprises

a first reflective member disposed on an object side of the first lens group, and

a mirror disposed between the first lens group and the imaging surface, the mirror being configured to reflect incident light, which is incident from the first lens group, toward the imaging surface by tilting with respect to an optical axis of the first lens group when shooting with the first lens group is performed, and to cause light, which is emitted from the second lens group, to fall incident on the imaging surface by being substantially perpendicular to the optical axis of the first lens group when shooting with the second lens group is performed, and

the second optical system comprises

a second reflective member disposed on an object side of the second lens group.
The imaging lens assembly according to claim 1, wherein the second optical system is configured to bend an optical path of light, which is emitted from the second lens group, toward the imaging surface side.
The imaging lens assembly according to claim 3, wherein the second optical system comprises a third reflective member disposed between the second lens group and the imaging surface side, the third reflective member being configured to reflect incident light, which is incident from the second lens group, toward the imaging surface.
The imaging lens assembly according to claim 1, wherein

the first optical system comprises a first aperture stop disposed between the first lens group and the first reflective member, and

the second optical system comprises a second aperture stop disposed between the second lens group and the second reflective member.
The imaging lens assembly according to claim 1, configured so that:

BFL2 /BFL1 > 1.2,

where BF1 is a distance on an optical axis of the first optical system from a surface on an imaging surface side of a most imaging surface side disposed lens of the first lens group to the imaging surface, and BF2 is a distance on an optical axis of the second optical system from a surface on an imaging surface side of a most imaging surface side disposed lens of the second lens group to the imaging surface.
The imaging lens assembly according to claim 5, configured so that:

50°> FOVm1 > 26°,

26°> FOVm2 > 10°,

where FOVm1 is twice the value of a maximum angle formed by an incident light, which is incident on the first aperture stop, with respect to the optical axis of the first lens group, FOVm1 being an angle of view of the first lens group, and FOVm2 is twice the value of a maximum angle formed by an incident light, which is incident on the second aperture stop, with respect to the optical axis of the second lens group, FOVm2 being an angle of view of the second lens group.
The imaging lens assembly according to claim 5, configured so that:

da1 < ds,

da2 < ds,

where da1 is a diameter of the first aperture stop, da2 is a diameter of the second aperture stop, and ds is a short side dimension of the imaging surface.
The imaging lens assembly according to claim 1, configured so that:

4.0mm < dd,

where dd is a half-diagonal length of the imaging surface.
The imaging lens assembly according to claim 1, wherein the mirror is configured to reflect the incident light, which is incident from the first lens group, toward a direction substantially perpendicular to the optical axis of the first lens group when shooting with the first lens group is performed.
The imaging lens assembly according to claim 2, wherein at least one of the first reflective member and the second reflective member is a prism.
The imaging lens assembly according to claim 2, wherein at least one of the first reflective member and the second reflective member is a mirror.
The imaging lens assembly according to claim 4, wherein the third reflective member is a prism.
The imaging lens assembly according to claim 4, wherein the third reflective member is a mirror.
The imaging lens assembly according to claim 1, wherein the first lens group and the second lens group comprise between 4 or more and 7 or less lenses.
The imaging lens assembly according to claim 3, wherein the optical axis of the first lens group and the optical axis of the second lens group are substantially parallel to each other.
The imaging lens assembly according to claim 1, wherein the optical axis of the first lens group and the optical axis of the second lens group are substantially perpendicular to each other.
The imaging lens assembly according to claim 1, wherein the second lens group is disposed farther from the imaging surface than the first lens group.
The imaging lens assembly according to claim 2, wherein the mirror is rotatable about a rotation axis located on one end side on the imaging surface side of the mirror.
The imaging lens assembly according to claim 1, wherein the shooting at the first angle of view is wide–angle shooting and the shooting at the second angle of view is telephoto shooting.
The imaging lens assembly according to claim 1, wherein

the first lens group comprises, in order from an object side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, a fourth lens having a positive refractive power, and a fifth lens having a negative refractive power, and

the second lens group comprises, in order from the object side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, and a fifth lens having a negative refractive power.
A camera module, comprising:

an imaging lens assembly according to any one of claims 1-21; and

an image sensor comprising an imaging surface.
The camera module according to claim 22, comprising an IR filter disposed between the imaging lens assembly and the image sensor.
An imaging device, comprising:

a camera module according to claim 22 or 23; and

a housing which houses the camera module.