(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2011/0261471 A1
`(43) Pub. Date:
`Oct. 27, 2011
`TANYAMA
`
`US 20110261471 A1
`
`(54) IMAGE PICKUP LENS, IMAGE PICKUP
`APPARATUS, AND PORTABLE TERMINAL
`DEVICE
`
`(75) Inventor:
`
`Minoru TANIYAMA, Saitama-shi
`(JP)
`
`(73) Assignee:
`
`FUJIFILM CORPORATION,
`Tokyo (JP)
`
`(21) Appl. No.:
`
`13/094,337
`
`(22) Filed:
`
`Apr. 26, 2011
`
`Publication Classification
`
`(51) Int. Cl.
`(2006.01)
`GO2B I3/8
`(2006.01)
`GO2B 9/34
`(52) U.S. Cl. ......................................... 359/715:359/773
`(57)
`ABSTRACT
`An image pickup lens that includes the following disposed
`from an object side in the order listed below: a first lens
`having a positive refractive power, a second lens having a
`negative refractive power; a third lens having a positive
`refractive power, and a fourth lens having an object side
`Surface which is concave or flat adjacent to an optical axis of
`the lens and a negative refractive power adjacent to the optical
`axis, and satisfies Conditional Expression (1) given below in
`order to realize totallength reduction and high image forming
`performance.
`
`(30)
`
`Foreign Application Priority Data
`
`Apr. 26, 2010 (JP) ................................. 2010-101 150
`
`where, R3 is a paraxial radius of curvature of an object side
`Surface of the second lens, and R4 is a paraxial radius of
`curvature of an image side Surface of the second lens.
`
`
`
`EXAMPLE 1
`
`G4
`
`CG
`
`sing
`
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`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 1 of 13
`
`US 2011/0261471 A1
`
`FIG.1 EXAMPLE 1.
`
`CG
`
`Sing
`
`FIG.2 example,
`
`
`
`G3
`
`R9 R10
`
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`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 2 of 13
`
`US 2011/0261471 A1
`
`
`
`FIG .3
`
`EXAMPLE 3
`
`FIG .4
`
`EXAMPLE 4
`G4
`
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`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 3 of 13
`
`US 2011/0261471 A1
`
`FIG.5
`
`EXAMPLE 5 64
`
`
`
`Sing
`
`FIG.6
`
`EXAMPLE 6
`
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`Exhibit 2018 Page 4 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 4 of 13
`
`US 2011/0261471 A1
`
`
`
`F G 7
`
`EXAMPLE 7
`
`EXAMPLE 8
`
`Apple v. Corephotonics
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`Exhibit 2018 Page 5 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 5 of 13
`
`US 2011/0261471 A1
`
`FIG.9
`
`EXAMPLE 9 G4
`
`CG Simg
`
`
`
`R7 R8 R9 Rio
`FIG.1 O EXAMPLE 10
`
`CG Sing
`
`G4
`
`DO
`
`D9
`f
`D82-D10
`
`R7 R8 -
`R9 R0
`
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`Exhibit 2018 Page 6 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 6 of 13
`
`US 2011/0261471 A1
`
`FIG.11 EXAMPLE 11
`
`
`
`CG sing
`
`-D10
`
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`Exhibit 2018 Page 7 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 7 of 13
`
`US 2011/0261471 A1
`
`FNO. 2.80
`
`EXAMPLE 1.
`
`E30.8
`
`(30.8
`
`: --SAGGITAL
`
`as a was TANGENTIAL
`
`
`
`0.2m
`-0.2mm
`SPHERICAL
`ABERRATION
`FG.12A
`
`-0. 2n 0.2mm
`ASTIGMATISM
`
`5%
`-5%
`DESTORTION
`
`FIG.12B
`
`FIG.12C
`
`FNO. 2.80
`
`
`
`EXAMPLE 2
`
`u-29.
`
`J229. 1
`
`--SAGGITAL
`
`
`
`a
`
`1- a 1
`
`a
`
`a TANGENTIAL
`
`0.2mm
`-0.2mm
`SPHERICAL
`ABERRATION
`F.G. 13A
`
`0.2m
`-0.2N
`ASTIGMATSM
`
`FIG.13B
`
`5%
`-5%
`DISTORTION
`
`FIG.13C
`
`Apple v. Corephotonics
`IPR2019-00030
`Exhibit 2018 Page 8 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 8 of 13
`
`US 2011/0261471 A1
`
`FNO. 2.80
`
`EXAMPLE 3
`
`ty=31.8
`
`E31.8
`
`------------ SAGGITAL
`
`
`
`-
`
`as a
`
`a TANGENTIA
`
`-0.2mm 0.2m
`SPHERICAL
`ABERRATION
`FIG.14A
`
`-0. 2n 0.2mm
`ASTIGMATSM
`
`5%
`-596
`DISTORTION
`
`FIG.14B
`
`FIG.14C
`
`FNO. 2.80
`
`
`
`EXAMPLE 4
`
`ty-34. O
`
`(J-34, 0'
`
`- SAGGITAL
`... TANGENTIAL
`
`
`
`-0.2in
`0.2m
`SPHERICAL
`ABERRATION
`FIG.15A
`
`0.2mm
`-0.2mm
`ASTIGMATSM
`
`FIG.15B
`
`5%
`w-5%
`DISTORTION
`
`FIG.15C
`
`Apple v. Corephotonics
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`Exhibit 2018 Page 9 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 9 of 13
`
`US 2011/0261471 A1
`
`EXAMPLE 5
`
`(JE31. 3
`
`y =31. 3
`
`-SAGGITAL
`
`
`
`- - - - - - - - TANGENTIAL
`
`0.2mm
`-0.2
`SPHERICAL
`ABERRATION
`FIG.16A
`
`-0.2m 0.2mm
`ASTIGMATISM
`
`FIG.16B
`
`5%
`-596
`DISTORTION
`
`FIG.16C
`
`FNO. 2.80
`
`
`
`EXAMPLE 6
`
`du-31. 3
`
`(231.3
`
`- SAGGITAL
`
`
`
`- - - - TANGENTIAL
`
`0.2m
`-0.2mm
`SPHERICAL
`ABERRATION
`FIG.17A
`
`0.2mm
`-0. 2pm
`ASTIGMATSM
`
`5%
`-5%
`DISTORTION
`
`FIG.17B
`
`FIG.17C
`
`Apple v. Corephotonics
`IPR2019-00030
`Exhibit 2018 Page 10 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 10 of 13
`
`US 2011/0261471 A1
`
`FNO. -2.80
`
`EXAMPLE 7
`
`(t)=31.5
`
`(U-31.5
`
`
`
`
`
`- SAGGITAL
`
`
`
`- - - - - - - - TANGENTIAL
`
`-0.2mm 0.2m
`SPHERICAL
`ABERRATION
`FIG.18A
`
`-0. 2n O. 2mm
`ASTIGMATSM
`
`596
`-5%
`DISTORTION
`
`FIG.18B
`
`FIG.18C
`
`FNO. -2.80
`
`EXAMPLE 8
`
`(U-34.5
`
`=34.5
`
`- SAGGITAL
`
`
`
`a v
`
`- - - TANGENTIAL
`
`-0.2m
`0.2mm
`SPHERICAL
`ABERRATION
`F.G. 19A
`
`0.2mm
`-0.2mm
`ASTIGMATSM
`
`FIG.19B
`
`5%
`-596
`DISTORTION
`
`FIG.19C
`
`Apple v. Corephotonics
`IPR2019-00030
`Exhibit 2018 Page 11 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 11 of 13
`
`US 2011/0261471 A1
`
`FNO. 2.80
`
`EXAMPLE 9
`
`=29. 1
`
`=29, 1
`
`- SAGGITAL
`
`
`
`a
`
`- -
`
`- - -
`
`- TANGENTIAL
`
`-0.2m 0.2mm
`SPHERICA
`ABERRATION
`FG.2OA
`
`-0.2m 0.2in
`ASTIGMATSM
`
`5%
`-596
`DISTORTION
`
`FIG.2OB
`
`FIG.20C
`
`FNO, 2.80
`
`
`
`EXAMPLE 10
`
`(U=30.
`
`E30. 1
`
`- SAGGITAL
`
`
`
`a
`
`- - - -
`
`- a TANGENTIAL
`
`-0. 2pm
`0.2mm
`SPHERICAL
`ABERRATION
`FG.21A
`
`0.2in
`-0. 2pm
`ASTIGMATSM
`
`596
`-5%
`DISTORTION
`
`FIG.21B
`
`FIG.21C
`
`Apple v. Corephotonics
`IPR2019-00030
`Exhibit 2018 Page 12 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 12 of 13
`
`US 2011/0261471 A1
`
`FNO. =2.80
`
`EXAMPLE 11
`
`(j-30.
`
`J-30. 1
`
`- SAGGITAL
`
`
`
`a a 1 TANGENTIAL
`
`-0.2mm
`0.2in
`SPHERICA
`ABERRATION
`FIG.22A
`
`-0.2mm 0.2m
`ASTIGMATSM
`
`596
`-596
`DISTORTION
`
`FIG.22B
`
`FG.22C
`
`
`
`
`
`3 LENS BARREL
`
`FIG.23
`
`SUPPORT
`SUBSTRATE
`
`EXTERNAL
`CONNECTION
`TERMINAL
`
`Apple v. Corephotonics
`IPR2019-00030
`Exhibit 2018 Page 13 of 30
`
`

`

`Patent Application Publication
`
`Oct. 27, 2011 Sheet 13 of 13
`
`US 2011/0261471 A1
`
`
`
`
`
`22 DISPLAY UNIT
`
`2A
`UPPER
`HOUSING
`
`
`
`
`
`FIG.24A
`
`HOUSING
`
`
`
`KEYS
`
`
`
`FIG.24B
`
`1 CAMERA UNIT
`
`Apple v. Corephotonics
`IPR2019-00030
`Exhibit 2018 Page 14 of 30
`
`

`

`US 2011/0261471 A1
`
`Oct. 27, 2011
`
`IMAGE PICKUP LENS, IMAGE PICKUP
`APPARATUS, AND PORTABLE TERMINAL
`DEVICE
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`0001
`0002 The present invention relates to an image pickup
`lens for forming an optical image of a subject on an image
`sensor, such as a CCD (charge coupled device), a CMOS
`(complementary metal oxide semiconductor), or the like, and
`an image pickup apparatus having the image pickup lens
`mounted thereon to perform imaging, such as a digital still
`camera or the like. The invention also relates to a portable
`terminal device, such as a camera-equipped cell phone, a
`personal digital assistance (PDA), or the like.
`0003 2. Description of the Related Art
`0004 Recently, along with the spread of personal comput
`ers to homes and the like, digital still cameras capable of
`inputting image information obtained by imaging a land
`scape, a person, or the like to a personal computer have been
`spreading rapidly. In addition, more and more cell phones
`have built-in camera modules for image input. Such devices
`with imaging capabilities employ image sensors such as
`CCDs, CMOSs, and the like. In recent years, these types of
`image sensors have been downsized greatly and, conse
`quently, imaging devices as a whole and image pickup lenses
`to be mounted on the devices have also been required to have
`more compact sizes. At the same time, the pixel count of
`imageSensors has been increasing, thereby causing a growing
`demand for improvement of image pickup lenses in resolu
`tion and performance.
`0005 Image pickup lenses, each formed of three or four
`lenses, are disclosed in U.S. Pat. Nos. 6,476,982, 7,466,497,
`7,715,119, 7,453,654, and 7,633,690, and U.S. Patent Appli
`cation Publication No. 2009015944, as well as in Japanese
`Unexamined Patent Publication Nos. 2007-017984, and
`2009-020182. As described in these documents, for a four
`element image pickup lens, in particular, a configuration of
`positive, negative, positive, and positive power arrangement
`from the object side or a configuration of positive, negative,
`positive, and negative power arrangement from the object
`side is known. In the case of such four-element image pickup
`lenses, the object side Surface of the most image side lens
`often has a convex shape in a paraxial region (adjacent to the
`optical axis). In the mean time, Japanese Unexamined Patent
`Publication No. 2007-017984 discloses, in Examples 5 and 9,
`a configuration of positive, negative, positive, and negative
`power arrangement with the object side Surface of the most
`image side lens having a concave shape adjacent to the optical
`axis of the lens.
`0006. As described above, downsizing and pixel count
`increase have been in progress for recent image sensors. For
`image pickup lenses of portable camera modules, in particu
`lar, cost reduction and compactness have been the major
`demands, but as the pixel count of image sensors even for
`portable camera modules tends to be increased, a demand for
`performance improvement is also growing. Consequently,
`development of wide variety of lenses comprehensively tak
`ing into account the cost, performance, and compactness is
`anticipated, and from the viewpoint of performance, devel
`opment of inexpensive and high performance image pickup
`lenses with a perspective of possible application to digital
`cameras is anticipated. The lenses described in the aforemen
`tioned patent documents have a shortcoming, for example, in
`
`compatibility between image forming performance and com
`pactness. Japanese Unexamined Patent Publication No.
`2007-017984 discloses various types of four-element image
`pickup lenses, but it is hard to say that optimization condi
`tions have been studied for each configuration example. Note
`that the present invention is a utilization invention of the
`invention described in Japanese Unexamined Patent Publica
`tion No. 2009-020182. As a result of further consideration of
`the balance between downsizing and performance for the
`image pickup lens described in Japanese Unexamined Patent
`Publication No. 2009-020182, the object of the present inven
`tion has been solved.
`0007. The present invention has been developed in view of
`the problems described above, and it is an object of the
`present invention to provide an image pickup lens reduced in
`overall length with enhanced image forming performance.
`
`SUMMARY OF THE INVENTION
`
`0008. An image pickup lens of the present invention
`includes the following from an object side in the order listed
`below: a first lens having a positive refractive power; a second
`lens having a negative refractive power; a third lens having a
`positive refractive power; and a fourth lens having an object
`side Surface which is concave or flat adjacent to an optical axis
`of the lens and a negative refractive power adjacent to the
`optical axis. The image pickup lens satisfies Conditional
`Expression (1) given below in which R3 is a paraxial radius of
`curvature of an object side surface of the second lens, and R4
`is a paraxial radius of curvature of animage side Surface of the
`second lens.
`
`0009. The image pickup lens of the present invention may
`provide advantageous effects for total length reduction and
`high image forming performance by optimizing the structure
`of each lens in a lens configuration of four lenses in total. In
`particular, the image pickup lens satisfies Conditional
`Expression (1) whereby the structure of the second lens is
`optimized. The image pickup lens of the present invention is
`advantageously configured for reducing a total length and
`obtaining high image forming performance even though the
`object side Surface of the most image side lens (fourth lens)
`has a flat or concave shape adjacent to the optical axis. Then,
`by employing the following preferable configurations as
`appropriate, the total length reduction and performance
`enhancement may be facilitated.
`0.3<lf24/fig.0.80
`
`(2)
`
`0.4<fl/f-1.1
`
`0.2<f3/f-1.6
`
`0.5<f2/fig2.0
`
`(3)
`
`(4)
`
`(5)
`
`20<w1-v2
`(6)
`where, f is an overall focal length, fl is a focal length of the
`first lens, f2 is a focal length of the second lens, f3 is a focal
`length of the third lens, and f4 is a focal length of the fourth
`lens, v1 is an Abbe number of the first lens with respect to
`d-line, and v2 is an Abbe number of the second lens with
`respect to d-line.
`
`Apple v. Corephotonics
`IPR2019-00030
`Exhibit 2018 Page 15 of 30
`
`

`

`US 2011/0261471 A1
`
`Oct. 27, 2011
`
`0010 Preferably, the image pickup lens of the present
`invention includes an aperture disposed on the object side of
`a Surface apex position of an image side Surface of the first
`lens on the optical axis.
`0011
`Preferably, in the image pickup lens of the present
`invention, each of the first, second, third, and fourth lenses has
`an aspherical shape on each side.
`0012. In the image pickup lens of the present invention, it
`is particularly preferable that the image side surface of the
`fourth lens has a concave shape adjacent to the optical axis
`and a region in which the negative refractive power becomes
`weak toward the periphery in comparison with a region adja
`cent to the optical axis.
`0013 An image pickup apparatus of the present invention
`is an apparatus, including the image pickup lens of the present
`invention and an image sensor for outputting an imaging
`signal according to an optical image formed by the image
`pickup lens.
`0014) A portable terminal device of the present invention
`is a device, including the image pickup apparatus of the
`present invention and a display unit for displaying an image
`taken by the image pickup apparatus.
`0015 The image pickup apparatus or the portable terminal
`device of the present invention may obtain a high resolution
`imaging signal based on a high resolution optical image
`obtained by the image pickup lens of the present invention.
`0016. The image pickup lens of the present invention may
`realize total length reduction and high image forming perfor
`mance by optimizing the shape and the like of each lens in a
`lens configuration of four lenses in total.
`0017. The image pickup apparatus or the portable terminal
`device of the present invention outputs an imaging signal
`according to an optical image formed by the image pickup
`lens of the present invention having high image forming
`performance, so that the apparatus or the device may obtain a
`high resolution image.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0018 FIG. 1 is a first example configuration of an image
`pickup lens according to an embodiment of the present inven
`tion, which corresponds to a cross-sectional view of Numeri
`cal Example 1.
`0019 FIG. 2 is a second example configuration of the
`image pickup lens, which corresponds to a cross-sectional
`view of Numerical Example 2.
`0020 FIG.3 is a third example configuration of the image
`pickup lens, which corresponds to a cross-sectional view of
`Numerical Example 3.
`0021
`FIG. 4 is a fourth example configuration of the
`image pickup lens, which corresponds to a cross-sectional
`view of Numerical Example 4.
`0022 FIG. 5 is a fifth example configuration of an image
`pickup lens according to an embodiment of the present inven
`tion, which corresponds to a cross-sectional view of Numeri
`cal Example 5.
`0023 FIG. 6 is a sixth example configuration of the image
`pickup lens, which corresponds to a cross-sectional view of
`Numerical Example 6.
`0024 FIG. 7 is a seventh example configuration of the
`image pickup lens, which corresponds to a cross-sectional
`view of Numerical Example 7.
`0025 FIG. 8 is an eighth example configuration of the
`image pickup lens, which corresponds to a cross-sectional
`view of Numerical Example 8.
`
`spherical aberration of
`
`0026 FIG.9 is a ninth example configuration of the image
`pickup lens, which corresponds to a cross-sectional view of
`Numerical Example 9.
`0027 FIG. 10 is a tenth example configuration of the
`image pickup lens, which corresponds to a cross-sectional
`view of Numerical Example 10.
`0028 FIG. 11 is an eleventh example configuration of the
`image pickup lens, which corresponds to a cross-sectional
`view of Numerical Example 11.
`0029 FIG. 12A illustrates
`Example 1.
`0030 FIG. 12B illustrates astigmatism of Example 1.
`0031 FIG. 12C illustrates distortion of Example 1.
`0032 FIG. 13A illustrates spherical aberration of
`Example 2.
`0033 FIG. 13B illustrates astigmatism of Example 2.
`0034 FIG. 13C illustrates distortion of Example 2.
`0035 FIG. 14A illustrates spherical aberration of
`Example 3.
`0036 FIG. 14B illustrates astigmatism of Example 3.
`0037 FIG. 14C illustrates distortion of Example 3.
`0038 FIG. 15A illustrates spherical aberration of
`Example 4.
`0039 FIG. 15B illustrates astigmatism of Example 4.
`0040 FIG. 15C illustrates distortion of Example 4.
`0041
`FIG. 16A illustrates spherical aberration of
`Example 5.
`0042 FIG. 16B illustrates astigmatism of Example 5.
`0043 FIG. 16C illustrates distortion of Example 5.
`0044 FIG. 17A illustrates spherical aberration of
`Example 6.
`0045 FIG. 17B illustrates astigmatism of Example 6.
`0046 FIG. 17C illustrates distortion of Example 6.
`0047 FIG. 18A illustrates spherical aberration of
`Example 7.
`0048 FIG. 18B illustrates astigmatism of Example 7.
`0049 FIG. 18C illustrates distortion of Example 7.
`0050 FIG. 19A illustrates spherical aberration of
`Example 8.
`0051 FIG. 19B illustrates astigmatism of Example 8.
`0052 FIG. 19C illustrates distortion of Example 8.
`0053 FIG. 20A illustrates spherical aberration of
`Example 9.
`0054 FIG. 20B illustrates astigmatism of Example 9.
`0055 FIG.20C illustrates distortion of Example 9.
`0056 FIG. 21A illustrates spherical aberration of
`Example 10.
`0057 FIG. 21B illustrates astigmatism of Example 10.
`0058 FIG. 21C illustrates distortion of Example 10.
`0059 FIG. 22A illustrates spherical aberration of
`Example 11.
`0060 FIG. 22B illustrates astigmatism of Example 11.
`0061 FIG. 22C illustrates distortion of Example 11.
`0062 FIG. 23 is a perspective view of a camera module, as
`an image pickup apparatus according to an embodiment of
`the present invention, illustrating an example structure
`thereof.
`0063 FIG.24A is an external view of a camera-equipped
`cell phone, as a portable terminal device according to an
`embodiment of the present invention, illustrating an example
`structure thereof.
`
`Apple v. Corephotonics
`IPR2019-00030
`Exhibit 2018 Page 16 of 30
`
`

`

`US 2011/0261471 A1
`
`Oct. 27, 2011
`
`0064 FIG.24B is an external view of a camera-equipped
`cell phone, as a portable terminal device according to an
`embodiment of the present invention, illustrating an example
`structure thereof.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`Lens Configuration
`0065 Hereinafter, embodiments of the present invention
`will be described in detail with reference to the accompanying
`drawings. FIG. 1 is a first example configuration of an image
`pickup lens according to an embodiment of the present inven
`tion. This example configuration corresponds to a lens con
`figuration of First Numerical Example, to be described later.
`Likewise, second to eleventh example configurations corre
`sponding to Second Numerical Example to Eleventh Numeri
`cal Example respectively are shown in FIGS. 2 to 11. In FIGS.
`1 to 11, the symbol Rirepresents a radius of curvature of ani"
`Surface, the Surface number being gradually incremented
`toward image side (image plane side) with the Surface of the
`lens element disposed on the most object side being taken as
`the first surface (aperture St being taken as zero" surface).
`Symbol Direpresents a surface separation betweeni" surface
`and i'+1 surface on optical axis Z1.
`0066. The image pickup lens according to the present
`embodiment includes from the object side in the order of
`aperture St, first lens G1, second lens G2, third lens G3, and
`fourth lens G4 along optical axis Z1.
`0067 Aperture St is an optical aperture stop which is
`preferable to be disposed on the object side of the surface apex
`of the image side Surface of lens G1 on optical axis Z1.
`thereby being disposed on the most object side of the lens
`system. Here, the term “most object side' as used herein
`includes not only the case in which aperture St is disposed at
`the surface apex position of the object side surface of first lens
`G1 as, for example, in the configuration shown in FIG. 3 but
`also the case in which aperture St is disposed between the
`surface apex position of the object side surface of first lens G1
`and the Surface apex position of the image side Surface of first
`lens G1 as in other configurations. It is more preferable that
`aperture St is disposed at a position on optical axis Z1 further
`object side, for example, between the Surface apex position of
`the object side surface of first lens G1 and edge position E
`(FIG. 1) of the object side surface of first lens G1.
`0068 Image plane Simg includes an image sensor, Such as
`a CCD or the like. Various types of optical members CG may
`be disposed between fourth lens G4 and the image sensor
`according to the camera side structure on which the lens is
`mounted. For example, flat plate optical members. Such as a
`coverglass for protecting the image plane and an infrared cut
`filter, may be disposed. In this case, for example, a flat plate
`cover glass with a coating having a filter effect, such as
`infrared cut filter, ND filter, or the like, applied thereon may
`be used as optical member CG. In the image pickup lens, all
`of lenses G1 to G4 or at least one lens surface may have a
`coating having a filter effect, such as infrared cut filter, ND
`filter, or the like, or an anti-reflection coating.
`0069 First lens G1 has a positive refractive power. Pref
`erably, first lens G1 has a biconvex shape adjacent to the
`optical axis.
`0070 Second lens G2 has a negative refractive power.
`Second lens G2 may be a lens having, adjacent to the optical
`axis, a biconcave shape (e.g., example configuration in FIG.
`1), a plano-concave shape with a flat Surface on the object side
`(e.g., example configuration in FIG. 3), a meniscus shape
`
`with a convex surface toward the object side (e.g., example
`configuration in FIG. 4), or the like.
`0071. Third lens G3 has an image side surface which is
`convex adjacent to the optical axis and a positive refractive
`power. For example, an object side surface of third lens G3 is
`concave adjacent to the optical axis.
`0072 Fourth lens G4 has an object side surface which is
`concave (e.g., example configures shown in FIGS. 1 and 2) or
`flat (e.g., example configures shown in FIGS. 3 and 4) adja
`cent to an optical axis of the lens and has a negative refractive
`power adjacent to the optical axis.
`(0073 Preferably, in each of first lens G1, second lens G2.
`third lens G3, and fourth lens G4, at least one surface is
`aspherical. The image side Surface of fourth lens G4, in par
`ticular, has a concave shape adjacent to the optical axis and a
`region in which the negative refractive power becomes weak
`toward the periphery in comparison with a region adjacent to
`the optical axis. Further, it is preferable that the image side
`Surface of fourth lens G4 has an aspherical shape having an
`inflexion point within an effective diameter. Still further, it is
`preferable that the image side surface of fourth lens G4 has an
`aspherical shape having a pole at a position other than the
`center of optical axis within the effective diameter. More
`specifically, it is preferable that, for example, the image side
`Surface of fourth lens G4 is an aspherical Surface having a
`concave shape toward the image side adjacent to the optical
`axis and a convex shape toward the image side in a peripheral
`region.
`0074. Here, if an aspherical shape is to be employed, sec
`ond lens G2, third lens G3, and fourth lens G4 tend to have a
`complicated shape with a large size in comparison with first
`lens G1. Therefore, it is preferable that each of second lens
`G2, third lens G3, and fourth lens G4 is made of a resin
`material in view of workabilitv and cost. Where manufactur
`ing cost is important, it is preferable that first lens G1 is also
`made of a resin material, but first lens G1 may be made of a
`glass material in order to improve performance.
`0075 Preferably, the image pickup lens satisfies Condi
`tional Expression (1) given below, in which R3 is a paraxial
`radius of curvature of the object side surface of second lens
`G2 and R4 is a paraxial radius of curvature of the image side
`surface of second lens G2.
`
`0076 Further, it is preferable that the image pickup lens
`selectively satisfies the following conditions as appropriate,
`in which fis an overall focallength, f1 is a focal length of first
`lens G1, f2 is a focal length of second lens G2, f3 is a focal
`length of third lens G3, and f4 is a focal length of fourth lens
`G4, v1 is an Abbe number of first lens G1 with respect to
`d-line, and v2 is an Abbe number of second lens G2 with
`respect to d-line.
`0.3<lf24/fig.0.80
`
`(2)
`
`0.4<fl/f-1.1
`
`0.2<f3/f-1.6
`
`0.5<f2/fig2.0
`
`(3)
`
`(4)
`
`(5)
`
`(6)
`
`20<w1-v2
`Example Application to Image Pickup Apparatus
`0077 FIGS. 24A and 24B illustrate a camera-equipped
`cellphone, as an example of portable terminal device accord
`ing to an embodiment. FIG. 23 illustrates an example struc
`ture of an image pickup apparatus according to an embodi
`ment. The camera-equipped cell phone illustrated in FIGS.
`24A and 24B includes upper housing 2A and lower housing
`2B which are pivotable in the allow directions in FIG. 24A.
`Lower housing 2B includes operation keys 21 and the like.
`Upper housing 2A includes camera unit 1 (FIG.24B), display
`
`Apple v. Corephotonics
`IPR2019-00030
`Exhibit 2018 Page 17 of 30
`
`

`

`US 2011/0261471 A1
`
`Oct. 27, 2011
`
`unit (display means) 22 (FIG.24A), and the like. Display unit
`22 includes a display panel Such as LCD (liquid crystal dis
`play), EL (electroluminescence) panel, or the like. Display
`unit 22 is disposed on a Surface which becomes an inner side
`when the housings are folded together. Display unit 22 is
`capable of displaying an image obtained by camera unit 1 and
`the like, in addition to various menu items related to telephone
`function. Camera unit 1 is disposed, for example, on the rear
`side of upper housing 2A, but the place where camera unit 1
`is provided is not limited to this.
`0078 Camera unit 1 includes, for example, a camera mod
`ule shown in FIG. 23. The camera module includes a lens
`barrel 3 in which image pickup lens 20 is accommodated,
`Support Substrate 4 for Supporting lens barrel 3, and an image
`sensor (not shown) provided at a position on Support Substrate
`4 corresponding to the image plane of image pickup lens 20,
`as shown in FIG. 23. Camera unit 1 further includes flexible
`Substrate 5 electrically connected to the image sensor pro
`vided on Support Substrate 4 and external connection terminal
`6 electrically connected to flexible substrate 5 and structured
`to be connectable to a signal processing circuit provided on
`the cell phone body. These components are integrally con
`structed.
`0079. In camera unit 1, an optical image formed by image
`pickup lens 20 is converted to an electrical imaging signal by
`the image sensor and the imaging signal is outputted to the
`signal processing circuit provided on the apparatus body. The
`use of the image pickup lens of the present embodiment as
`image pickup lens 20 of Such camera-equipped cell phone
`allows a sufficiently aberration corrected high resolution
`imaging signal to be obtained. Cellphone body may generate
`a high resolution image based on the imaging signal.
`0080. The image pickup lens of the present embodiment
`may be applied to various types of image pickup apparatuses
`and portable terminal devices that employ image sensors,
`such as CCD, CMOS, and the like. The image pickup appa
`ratus orportable terminal device of the present embodiment is
`not limited to a camera-equipped cellphone and it may be, for
`example, a digital still camera, a PDA, or the like.
`
`Operation and Advantageous Effects
`0081. An operation and advantageous effects of the image
`pickup lens configured in the aforementioned manner will
`now be described. The image pickup lens according to the
`present embodiment may provide advantageous effects for
`total length reduction and high image forming performance
`by arranging the powers of the lenses from the object side in
`the order of positive, negative, positive, and negative, appro
`priately setting a Surface shape of each lens, and satisfying a
`predetermined conditional expression in a lens configuration
`of four lenses in total. In particular, the image pickup lens is
`advantageously configured for reducing the total length and
`obtaining high image forming performance even though the
`object side surface of the most image side lens (fourth lens
`G4) has a flat or concave shape adjacent to the optical axis.
`Further, the negative refractive power of fourth lens G4 pro
`vides an advantageous effect of ensuring a Sufficient back
`focus. If positive refractive power of fourth lens G4 is too
`strong, it is difficult to ensure a sufficient back focus.
`
`I0082 Further, in the image pickup lens, the use of an
`aspherical surface for at least one surface of each of first lens
`G1, second lens G2, third lens G3, and fourth lens G4 pro
`vides an advantageous effect for maintaining aberration per
`formance. In fourth lens G4, in particular, the light flux is
`separated with respect to each angle of view in comparison
`with first lens G1, second lens G2, and third lens G3. By
`making the image side Surface of fourth lens G4, which is the
`lens Surface closest to the image sensor, concave toward the
`image side adjacent to the optical axis and convex toward
`image side in a peripheral portion, aberration with respect to
`each angle of view is corrected appropriately and the incident
`angle of the light flux on the image sensor is controlled below
`a predetermined angle. This may reduce the unevenness in
`light amount over the entire region of the image plane and
`provide an advantageous effect for correcting curvature of
`field, distortion, and the like.
`I0083 Generally, it is preferable that image pickup lens
`systems have telecentricity, that is, it is preferable that the
`incident angle of the chief ray becomes substantially parallel
`to the optical axis (incident angle on the image plane becomes
`close to zero with respect to normal line). In order to ensure
`the telecentricity, it is preferable that aperture Stis disposed at
`a position as close to the object side as possible. On the other
`hand, if aperture St is disposed at a position furtheraway from
`the object side surface of first lens G1 in the object side
`direction, the distance between aperture Stand the object side
`surface of first lens G1 is added to the optical path, which is
`disadvantageous for downsizing the overall configuration.
`Consequently, telecentricity may be ensured while reducing
`the total length by disposing aperture St at a position on
`optical axis Z1 corresponding to the Surface apex position of
`the object side surface of first lens G1 or a position on optical
`axis Z1 between the surface apex position of the object side
`surface of first lens G1 and the surface apex position of the
`image side surface of first lens G1. Where the telecentricity is
`more important, aperture St may be disposed at a position on
`optical axis Z1 between the surface apex position of the object
`side surface of first lens G1 and edgeposition E (FIG.1) of the
`object side surface of first lens G1.
`I0084 Conditional Expression (1) given above is related to
`the shape and refractive power of second lens G2. If (R4+
`R3)/(R4-R3) exceeds the upper limit of Conditional Expres
`sion (1), the refractive power of second lens becomes too
`weak, causing a disadvantageous effect for the total length
`reduction. While if (R4+R3)/(R4-R3) exceeds the lower
`limit of Conditional Expression (1), the refractive power of
`second lens becomes too strong, causing difficulty in aberra
`tion correction. In order to reduce the total length and to
`obtain high image forming performance, it is preferable that
`the numerical rang