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`
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`
`(10) Patent No.:
`US 7,777,972 B1
`(12) Unlted States Patent
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`
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`Aug. 17, 2010
`Chen et al.
`(45) Date of Patent:
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`USOO7777972B1
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`(54)
`
`(75)
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`IMAGING OPTICAL LENS ASSEMBLY
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`Inventors: Chun_shan (:hena Taichung (TW);
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`Hsiang-Chi Tang, Taichung (TW)
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`( * ) Notice:
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`(22)
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`(73) Assignee: Largan Precision Co., Ltd., Taichung
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`(TW)
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`Subject to any disclaimer, the term of this
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`patent is extended or adjusted under 35
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`U'S'C' 154(1)) by Odays.
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`(21) Appl.No.: 12/483,748
`Filed:
`Jun. 12, 2009
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`Forelgn Appllcatlon Prlorlty Data
`(30)
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`(TW)
`.............................. 98105232 A
`Feb. 19, 2009
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`(51)
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`(56)
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`Int. Cl-
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`(200601)
`G023 9/34
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`(200601)
`G02B 13/18
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`........................ 359/773; 359/715; 359/740
`(52) US. Cl.
`(58) Field of Classification Search ................. 359/715,
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`359/738, 740, 773
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`See application file for complete search history.
`References Cited
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`U.S. PATENT DOCUMENTS
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`7,477,459 B2 *
`l/2009 Liao ........................... 359/773
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`7,492,532 B2 *
`2/2009 Shin .......... 359/773
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`2004/0136097 A1 *
`7/2004 Park ............. 359/773
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`2007/0188890 A1*
`8/2007 Jo et a1.
`...................... 359/773
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`.............. 359/773
`1/2009 Teraoka etal.
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`l/2009 Taniyama ......
`359/773
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`8/2009 Shinohara ................... 359/773
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`2009/0009889 A1*
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`2009/0015944 A1*
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`2009/0207507 A1 *
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`* cited by examiner
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`Primary ExamineriEvelyn A. Lester
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`(74) Attorney, Agent, or FirmiBirch, Stewart, Kolasch &
`Birch, LLP
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`ABSTRACT
`(57)
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`lens
`invention provides an imaging optical
`The present
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`assembly including, in order from the object side to the image
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`side: a first lens group comprising a first lens element with
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`positive refractive power, no lens element with refractive
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`power being disposed between the first lens element and an
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`imaged object, the first lens element being the only lens
`element with refractive power in the first lens group; and a
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`second lens group comprising, in order from the object side to
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`the image side: a second lens element with negative refractive
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`power; a third lens element; and a fourth lens element;
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`wherein focusing adjustment is performed by moving the first
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`lens element along an optical axis, such that as a distance
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`between the imaged object and the imaging optical lens
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`assembly changes from far to near, a distance between the
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`first lens element and an image plane changes from near to
`far; and wherein the number of the lens elements with refrac-
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`t1ve power in the 1mag1ng optical lens assembly 1s N, and 1t
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`satisfies the relation: 4§N§5 The abovementioned arrange-
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`ment of optical elements and focusing adjustment method
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`enable the imaging optical lens assembly to obtain good
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`.
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`image quallty and consume less power.
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`19 Claims, 16 Drawing Sheets
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`APPL-1024 / Page 1 of 23
`Apple v. Corephotonics
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`APPL-1024 / Page 1 of 23
`Apple v. Corephotonics
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`US. Patent
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`Aug. 17, 2010
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`Sheet 1 of 16
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`US 7,777,972 B1
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`21
`101
`102111 112 i >
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`121
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`122
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`Fig.1
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`APPL-1024 / Page 2 of 23
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`APPL-1024 / Page 2 of 23
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`U.S. Patent
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`Aug. 17, 2010
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`Sheet 2 of 16
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`US 7,777,972 B1
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`APPL-1024 / Page 3 of 23
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`APPL-1024 / Page 3 of 23
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`U.S. Patent
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`‘Aug.17,2010
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`Sheet 3 of 16
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`US 7,777,972 B1
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`US. Patent
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`Aug. 17, 2010
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`Sheet 4 of 16
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`US 7,777,972 B1
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`APPL-1024 / Page 5 of 23
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`U.S. Patent
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`‘Aug.17,2010
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`APPL-1024 / Page 6 of 23
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`APPL-1024 / Page 7 of 23
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`APPL-1024 / Page 7 of 23
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`US. Patent
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`Aug. 17, 2010
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`Sheet 7 of 16
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`US 7,777,972 B1
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`APPL-1024 / Page 8 of 23
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`APPL-1024 / Page 8 of 23
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`APPL—1024 / Page 10 of 23
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`APPL-1024 / Page 10 of 23
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`US. Patent
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`Aug. 17, 2010
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`Sheet 10 of 16
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`US 7,777,972 B1
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`TABLE 1
`
`
`(Embodiment l)
`
`f= 4.33 mm, Fno = 2.90, HFOV = 33.5 deg.
`
`
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`
`Index
`Curvature Radius
`Thickness Material
`Surface #
`Abbe #
`11:3;;
`
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`
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`
`
`
`
`
`Object
`0
`Plano
`Infmity
`
`
`Ape. Stop
`Plano
`
`
`Lens 1
`2.16949 (ASP)
`
`
`
`
`-5.88250 (ASP)
`
`
`
`100.00000 (ASP)
`
`
`
`0.614
`3.21670 (ASP)
`
`
`
`0.766
`-2.18540 (ASP)
`
`
`
`-1 .04238 (ASP)
`
`
`
`0.581
`2.90877 (ASP)
`
`
`
`0.300
`0.96623 (ASP)
`
`
`
`0.200
`Plano
`
`
`0.500
`Plano
`
`
`0.300
`
`
`
`
`14 Plano Image
`
`
`
`
`—0.089
`
`0.900
`
`0.200
`
`0.383
`
`0.070
`
`Plano
`
`Plano
`
`0.484
`
`
`
`Lens 2
`
`
`Lens 3
`
`
`Lens 4
`
`
`IR—filter
`
`
`
`Cover Glass
`
`
`
`
`l
`
`2
`
`3
`
`4
`
`5
`
`6
`
`7
`
`
`
`8
`9
`10
`
`1 1
`
`12
`
`13
`
`Plastic
`
`
`
`1.544
`
`
`
`55.9
`
`
`
`3.03
`
`
`
`Plastic
`
`
`
`1.632
`
`
`
`23 .4
`
`
`
`-5.27
`
`
`
`Plastic
`
`
`
`1.530
`
`
`
`55.8
`
`
`
`3.05
`
`
`
`Plastic
`
`
`
`1.530
`
`
`
`55.8
`
`
`
`-3.05
`
`Glass
`
`Glass
`
`
`
`
`
`1.517
`
`
`
`64.2
`
`
`
`1.517
`
`
`
`64.2
`
`
`
`-
`
`-
`
`
`
`
`
`
`
`
`
`
`*Object Distance 100 mm: surface 3 thickness =
`
`
`
`
`0.287 m, f = 4.23 mm
`
`Fig.7
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`
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`APPL—1024 / Page 11 of 23
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`APPL-1024 / Page 11 of 23
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`US. Patent
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`Aug. 17, 2010
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`Sheet 11 of 16
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`US 7,777,972 B1
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`TABLEZ
`
`
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`Aspheric Coefficients
`
`
`3
`
`
`
`4
`
`
`
`5
`
`
`
`
`SUIface#
`
`2
`
`
`
`
`k =
`
`A4:
`
`A6=
`
`A8=
`
`A10 =
`
`A12 =
`
`A14 :
`
`A16= —2.03569E+00
`
`
`
`
`
`-6.42322E+00 0.00000E+00 -1.00000E+03 —1.63883E+01
`
`
`
`
`5.41140E-02 —1.09227E-02
`
`
`
`
`-1.96445E—02 —5.15556E—02
`-1.82457E—01
`-1.94068E-01
`
`
`
`-1.14833E—01
`
`
`
`2.44208E-02 "1.16446E-01 —1.06404E—01
`7.09572E—01
`
`
`
`-2.32230E+00 -4.66235E-02 -2.68287E—01
`
`
`
`3.54279E+00 -3.82606E-04 4.12009E-01
`
`
`—1.82905E-01
`
`
`6.01150E—02
`
`1.56920E—0]
`
`2.49347E—02
`
`2.74168E—01
`
`
`
`2.21172E—01
`
`-4.40642E—02
`
`8.18527E-02
`
`-2.86683E—02
`
`
`
`
`
`
`
`
`
`
`
`Surface#
`6
`7
`8
`9
`
`
`
`
`
`
`k = —2.29304E+01 -4.53794E+00 —3.30328E+00 —5.73407E+00
`
`
`
`A4 =
`-1.16793E—01
`-1.19883E—01
`
`
`
`A6 =
`1.94942E-01
`
`
`
`A8 =
`-3.69015E-01
`
`
`
`A10=
`2.56431E-01
`-2.21268E—02 -2.89861E-03
`
`
`
`A12 2
`
`
`
`-1.65957E-01
`
`
`
`A16=
`6.3 864013—02 —9.9819OE—04 —3.06196E—05
`
`3.58178E-02
`
`3.08158E-03
`
`5.95191E-02
`
`1.13277E—02
`
`A14:
`
`1.86502E-03
`
`7.07747E—02
`
`4.13104Ew02
`
`2.95065E-03
`
`1.72668E-04
`
`7.44048E—05
`
`
`-2.18847E—01 —1.13293E—01
`
`
`-4.89029E-03 —1.28908E-02
`
`
`3.46094E-04 —5.61966E—04
`
`
`
`
`
`
`
`
`
`
`
`
`-4.89505E—06
`
`Fig.8
`
`
`
`APPL—1024 / Page 12 of 23
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`APPL-1024 / Page 12 of 23
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`US. Patent
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`Aug. 17, 2010
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`Sheet 12 of 16
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`
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`US 7,777,972 B1
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`Plano
`
`Object
`
`
`
`Ape. Stop
`Lens 1
`
`
`
`
`Lens 2
`
`
`Lens 3
`
`
`1
`
`3
`
`5
`
`7
`
`
`
`
`
`
`
`—0.102
`
`0.900
`
`0.200
`
`0.346
`
`0.504
`
`0.761
`
`0.600
`
`
`Index
`
`
`
`
`
`Abbe #
`
`
`11;2023:1111
`
`
`Plastic
`
`
`
`1.544
`
`
`
`55.9
`
`
`
`2.99
`
`
`
`Plastic
`
`
`
`1.632
`
`
`
`23.4
`
`
`
`-5.33
`
`
`
`Plastic
`
`
`
`1.544
`
`
`
`55.9
`
`
`
`4.70
`
`
`
`TABLE 3
`
`(Embodiment 2)
`
`
`
`
`
`
`
`
`
`f= 4.25 mm, Fno = 2.90, HFOV = 33.5 deg.
`Curvature Radius Thickness Material
`
`
`
`
`
`Plano
`Infinity
`
`1.89503 (ASP)
`
`
`—9.59770 (ASP)
`
`
`4159870 (ASP)
`
`
`4.01330 (ASP)
`
`
`-3.30370 (ASP)
`
`
`-1 .55897 (ASP)
`
`
`2.57806 (ASP)
`
`
`1.10343 (ASP)
`
`
`Plano
`
`Surface #
`
`
`0
`
`2
`
`
`4
`
`
`6
`
`
`
`9
`
`10
`
`
`12
`
`1 1
`
`13
`
`
`
`
`14
`
`8
`
`Lens 4
`
`
`IR—filter
`
`
`
`Cover Glass
`
`
`
`
`Image
`
`
`
`0.350
`
`0.300
`0.200
`
`0.500
`
`0.300
`
`0.089
`
`
`
`
`
`
`
`
`Plano
`
`Plano
`
`Plano
`
`Plano
`
`
`
`
`
`
`
`Plastic
`
`
`
`1.530
`
`Glass
`
`
`
`1.517
`
`Glass
`
`
`
`1.517
`
`
`
`
`
`
`
`
`
`
`
`
`*Object Distance 100 mm: surface 3 thickness = 0.283 m, f = 4.36 mm
`
`Fig.9
`
`
`
`
`
`
`
`
`
`55.8
`
`
`
`-3.97
`
`
`
`64.2
`
`
`
`64.2
`
`
`
`-
`
`-
`
`APPL—1024 / Page 13 of 23
`
`APPL-1024 / Page 13 of 23
`
`

`

`
`US. Patent
`
`
`
`
`Aug. 17, 2010
`
`
`
`
`Sheet 13 of 16
`
`
`
`US 7,777,972 B1
`
`
`TABLE4
`
`
`Aspheric Coefficients
`
`
`3
`
`
`
`4
`
`
`
`5
`
`
`
`
`Surface#
`
`2
`
`
`
`6.32581E—02
`
`5.09665E—03
`
`8.43 18113-02
`
`3.35220E—02
`
`
`
`
`
`
`-3.87349E+00 0.00000E+00 1.25366E+02 —3.52526E+01
`k =
`
`
`
`
`
`1.78238E—01
`A4 :-
`
`
`
`
`
`A6 = —4.00870E-02 —4. 184411302 ~1.59342E-01 -1.84920E-01
`
`
`
`
`
`A8 = —5.03443E—02
`2.35534E-01
`2.13392E—01
`
`
`
`
`
`7.64212E—01 ~2.23277E-02 -1.18827E-01 -l.O4308E—01
`A10 =
`
`
`
`
`A12 = —2.58608E+00 8.22940E-03 -2.49182E-01 —4.03773E—02
`
`
`
`
`A14 =
`3.71028E+00 -2.02587E-02 4.34601E-01
`
`
`
`-2.09716E-01 -3.19236E-02
`
`A16=
`
`~1.98186E+OO
`
`8.43271E-02
`
`
`
`
`
`
`Surface#
`
`6
`
`
`
`7
`
`
`
`8
`
`
`
`9
`
`
`
`
`k =
`
`
`
`-6.08404E+O] -3.51853E+()0 ~6.80667E+OI -7.60755E+00
`
`
`
`
`
`A4 = —1.90860E—01
`
`
`
`
`
`-9.19376E—02 -2.22385E-01 -1.25750E—01
`
`A10=
`
`
`A6 =
`
`A8 =
`
`
`A12 3
`
`A14z
`
`
`A16:
`
`
`2.58744E-01
`
`2.04732E—02
`
`7.47643E—02
`
`4.7132913—02
`
`2.46479E—01
`
`6.78949E-02
`
`1.26764E—02
`
`2.69255E—04
`
`-5.75776E—04
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`5.82878E—03 —4.26188E—03 —I.49248E—02
`-3.73925E-01
`
`
`
`
`-1.72439E-02 —3.05562E-03 3.37376E-03
`
`
`
`
`
`
`
`~1.56664E-01
`
`
`
`-1.7107OE-03 -2.55825E—05 -3.47004E—06
`
`1.56195E—03
`
`1.64291E-04
`
`6.22629E-05
`
`
`5.4883013—02
`
`Fig.10
`
`
`
`APPL—1024 / Page 14 of 23
`
`APPL-1024 / Page 14 of 23
`
`

`

`
`U.S. Patent
`
`
`
`
`Aug. 17, 2010
`
`
`
`
`Sheet 14 0f 16
`
`
`
`US 7,777,972 B1
`
`TABLE 5
`
`
`(Embodiment 3)
`
`
`
`
`
`
`
`
`f= 4.23 mm. Fno = 2.90 HFOV = 33.5 deg
`Thickness
`Material
`Index
`Curvature Radius
`
`
`Plano
`
`
`
`
`
`
`
`
`
`1.83571 (ASP)
`
`
`—9.26100 (ASP)
`
`
`~6.73390 (ASP)
`
`
`6.20280 (ASP)
`
`
`~2.41850 (ASP)
`
`
`-1.12530 (ASP)
`
`
`1.90758 (ASP)
`
`
`0.85107 (ASP)
`
`
`Plano
`
`Plano
`
`Plano
`
`Plano
`
`
`
`
`
`Infinity
`0.102
`
`
`
`
`
`0.555
`
`
`
`0.900
`
`0.200
`
`0.31 1
`
`0.736
`
`0.261
`
`0.320
`
`0.300
`
`0.200
`
`0.500
`
`0.300
`
`
`Abbe #
`
`Focal
`
`length
`
`55.9
`
`23.4
`
`55.9
`
`55.9
`
`64.2
`
`64.2
`
`
`
`
`
`
`
`
`
`
`
`
`
`2.90
`
`
`
`-5.06
`
`
`
`3.22
`
`
`
`-3.16
`
`
`
`—
`
`-
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Surface #
`
`
`\DOQQONUIAWNHO
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`,_.,_1,_....1ri—io
`
`
`14
`
`
`
`Object
`
`Ape. Stop
`Lens 1
`
`
`
`
`Lens 2
`
`
`Lens 3
`
`
`Lens 4
`
`
`IR~fi1ter
`
`
`
`Cover Glass
`
`
`
`
`Image
`
`Plastic
`
`Plastic
`
`
`
`
`
`Plastic
`
`
`1.544
`
`1.632
`
`1.544
`
`Plastic
`
`
`
`1.544
`
`Glass
`
`Glass
`
`
`
`
`
`1.517
`
`1.517
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`*Object Distance 100 mm: surface 3 thickness =
`
`Plano
`
`Plano
`
`0.474
`
`
`
`
`0.278 mm, f= 4.35 mm
`
`Fig.11
`
`
`
`APPL—1024 / Page 15 of 23
`
`APPL-1024 / Page 15 of 23
`
`

`

`
`US. Patent
`
`
`
`
`Aug. 17, 2010
`
`
`
`
`Sheet 15 of 16
`
`
`
`US 7,777,972 B1
`
`
`TABLE6
`
`
`Aspheric Coefficients
`
`
`3
`
`
`
`
`
`5
`
`
`
`
`Surface#
`
`2
`
`
`
`
`
`
`
`
`
`-1.18048E+02 ~4.86168E+01
`k : —3_68354E+00 4.27537B—01
`
`
`
`
`
`1.87208E-01
`A4=
`6.60970E-02
`
`
`
`
`
`A6: —3.92891E-02 -4.02627B—02 —l.61690E—01 -1.84789E—01
`
`
`
`
`
`A8: —5.48599E-02 3.32827E—02
`
`
`
`
`
`A10:
`7.6770713-01
`-2.18444E-02 —l.10007E-01 -1.00444E—01
`
`
`
`
`
`A12: —2.57677E+00 9.96757E-O3
`-2.51777E-OI —3.29311E—02
`
`
`
`
`
`A14:
`3.69371E+00 —3.24649E~02
`
`
`
`
`
`~1.98154E+00 -3-55830E-04 -2.15316E-01 —4.33497E-02
`
`4.25004E-03
`
`
`8.41135E-02
`
`2.46696E—01
`
`2.09987E—01
`
`4.19955E—0]
`
`8.88264E—02
`
`A16=
`
`6
`
`
`
`7
`
`
`
`
`
`9
`
`
`
`
`2.67223E~01
`
`1.47155E-02
`
`7.38545E-02
`
`5.61405E-02
`
`6.7647713-02
`
`1.30256E—02
`
`1.56088E-03
`
`1.63916E-04
`
`6.68925E—05
`
`
`Surface#
`
`
`
`~3.22944E+01 -3.25133E+00 -4.08630E+01 -6.51806E+00
`k =
`
`
`
`
`A4: —2.08072E—01 —9.36284E-02 -2.08003E-01 —1.43476E-01
`
`
`
`A6=
`
`
`
`
`A8: —3.84575E~01
`5.87603E-03 -4.41204E-03 -1.67975E-02
`
`
`
`
`A107-
`2.37336E-01 —1.59335E—02 -3.08231E-03 3.32273E—03
`
`
`
`
`A12:
`2.62777E—04 -5.28673E—04
`
`
`
`
`A14= —l.53505E—01
`
`
`
`
`A16:
`5.58447E-02 ~1.82229E—03 -2.51552E~05 -5.25040E—06
`
`
`
`
`
`
`
`
`
`
`
`Fig.12
`
`APPL—1024 / Page 16 of 23
`
`APPL-1024 / Page 16 of 23
`
`

`

`
`US. Patent
`
`
`
`
`Aug. 17, 2010
`
`
`
`Sheet 16 of 16
`
`
`
`
`US 7,777,972 B1
`
`
`TABLE 7
`
`
`
`
`Embodiment Embodiment Embodiment
`
`
`
`1
`2
`3
`
`
`
`f
`
`
`Fno
`
`HFOV
`
`
`
`N
`
`
`
`4.33
`
`2.90
`
`33.5
`
`
`
`
`
`4
`
`
`
`
`
`
`
`4.25
`
`2.90
`
`33.5
`
`4
`
`
`
`
`
`
`
`4.23
`
`2.90
`
`33.5
`
`4
`
`
`
`finax/fmin
`
`
`
`IBFLl-BFLZI
`
`(D1-D2)*100/f
`
`
`
`
`V1
`
`
`V2
`
`13/11
`
`1713
`
`1.02
`
`0.0
`
`2.02
`
`55.9
`
`23.4
`
`1.43
`
`1.42
`
`
`
`
`
`
`
`
`
`T34/T23
`
`
`
`
`0.11
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`TTL/ImgH
`1.84
`1.75
`1.75
`
`
`1.03
`
`0.0
`
`1.98
`
`55.9
`
`23.4
`
`1.42
`
`0.90
`
`1.19
`
`1.03
`
`0.0
`
`1.87
`
`55.9
`
`23.4
`
`1.46
`
`
`
`
`
`
`
`
`
`1.31
`
`0.47
`
`
`
`Fig. 1 3
`
`
`
`APPL—1024 / Page 17 of 23
`
`APPL-1024 / Page 17 of 23
`
`

`

`
`
`US 7,777,972 B1
`
`1
`
`IMAGING OPTICAL LENS ASSEMBLY
`
`
`
`
`
`
`BACKGROUND OF THE INVENTION
`
`
`
`
`
`2
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`10
`
`
`
`15
`
`
`
`
`
`
`
`
`
`
`
`second lens element with negative refractive power; a third
`lens element; and a fourth lens element; and wherein the
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`method for performing focusing includes moving the first
`
`
`
`
`
`
`
`
`lens element along the optical axis, such that as a distance
`
`
`
`
`
`
`
`
`between the imaged object and the imaging optical lens
`
`
`
`
`
`
`
`assembly changes from far to near, a distance between the
`
`
`
`
`
`
`
`
`first lens element and the imaging surface changes from near
`
`
`
`
`
`
`
`
`
`to far, and during focusing the other lens elements in the
`
`
`
`
`
`
`
`
`imaging optical lens assembly can either move or not move
`
`
`
`
`relative to the imaging plane.
`
`
`
`
`
`
`
`The aforementioned arrangement of lens groups can effec-
`
`
`
`
`
`
`
`
`tively improve the image quality of the imaging optical lens
`
`
`
`
`
`
`
`assembly. In the present imaging optical lens assembly, a
`single lens element, the first lens element, is selected to move
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`along the optical axis to perform the focusing adjustment so
`
`
`
`
`
`
`
`
`
`that less power will be consumed during the focusing process.
`
`
`
`
`
`
`
`
`
`In addition, by selecting the first lens element to perform
`
`
`
`
`
`
`
`
`focusing adjustment,
`the number of lens groups can be
`
`
`
`
`
`
`
`reduced to effectively reduce the variability in the assembly/
`
`
`
`
`
`manufacturing of the imaging optical lens assembly.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`
`
`
`1. Field of the Invention
`
`
`
`
`
`
`
`
`
`The present invention relates to an imaging optical lens
`
`
`
`
`
`
`assembly, and more particularly, to an imaging optical lens
`
`
`
`
`assembly with focusing adjustment.
`
`
`
`
`2. Description of the Prior Art
`
`
`
`
`
`
`
`
`
`In recent years, with the popularity of camera mobile
`
`
`
`
`
`
`
`phones, the demand for compact photographing lenses is
`
`
`
`
`
`
`increasing, and the sensor of a general photographing camera
`
`
`
`
`
`
`
`
`
`is none other than CCD (charge coupled device) or CMOS
`
`
`
`
`
`device
`(Complementary Metal Oxide Semiconductor
`device). Furthermore, as advanced semiconductor manufac-
`
`
`
`
`
`
`
`
`
`
`
`
`
`turing technology has allowed the pixel size of sensors to be
`
`
`
`
`
`
`
`reduced and compact photographing lenses have gradually
`
`
`
`
`
`
`
`evolved toward higher megapixels, there is an increasing
`
`
`
`
`
`
`demand for compact photographing lenses featuring better
`
`
`image quality.
`
`
`
`
`
`
`A conventional compact photographing lens equipped in a
`
`
`
`
`
`
`
`
`mobile phone is usually a single focus lens having a fixed
`
`
`
`
`
`
`
`
`
`focal length. For a specific object distance, since the photo-
`
`
`
`
`
`
`
`
`graphing lens has a limited depth of field, it is apt to produce
`
`
`
`
`
`
`
`blurred images. Therefore, as the resolution of compact pho-
`
`
`
`
`
`
`tographing lenses increases, a focusing adjustment function
`
`
`
`
`
`
`
`becomes more and more indispensable as well. Generally, a
`
`
`
`
`
`
`
`photographing lens with focusing adjustment function per-
`
`
`
`
`
`
`
`forms focusing adjustment by using a driving motor to move
`
`
`
`
`
`
`
`
`the entire photographing lens relative to the sensor. However,
`
`
`
`
`
`
`
`such a photographing lens requires higher power consump-
`
`
`
`
`
`
`
`
`
`tionbecause the driving motor is configured to drive the entire
`
`
`
`
`
`
`
`photographing lens. Moreover, the photographing lens has a
`
`
`
`
`
`relatively long total track length.
`SUMMARY OF THE INVENTION
`
`
`
`20
`
`25
`
`30
`
`35
`
`
`
`40
`
`45
`
`
`
`
`
`
`
`
`The present invention provides an imaging optical lens
`
`
`
`
`
`
`
`
`
`assembly including, in order from the object side to the image
`
`
`
`
`
`
`
`
`
`side: a first lens group comprising a first lens element with
`
`
`
`
`
`
`
`
`positive refractive power, no lens element with refractive
`
`
`
`
`
`
`
`
`
`power being disposed between the first lens element and an
`
`
`
`
`
`
`
`
`
`
`imaged object, the first lens element being the only lens
`element with refractive power in the first lens group; and a
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`second lens group comprising, in order from the object side to
`
`
`
`
`
`
`
`
`
`the image side: a second lens element with negative refractive
`power; a third lens element; and a fourth lens element; focus-
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`ing is performed by moving the first lens element along the
`
`
`
`
`
`
`
`
`optical axis, such that as a distance between the imaged object
`
`
`
`
`
`
`
`
`
`and the imaging optical lens assembly changes from far to
`near, a distance between the first lens element and the imaging
`
`
`
`
`
`
`
`
`
`
`
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`surface changes from near to far, and during focusing the
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`other lens elements in the imaging optical lens assembly do
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`not move relative to the imaging plane; and wherein the
`number of the lens elements with refractive power in the
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`imaging optical lens assembly is N, and it satisfies the rela-
`tion: 4§N§5
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`According to one aspect of the present invention, there is
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`provided a method for performing focusing for an imaging
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`optical lens assembly; wherein the lens assembly includes, in
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`order from the object side to the image side: a first lens group
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`comprising a first lens element with positive refractive power,
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`no lens element with refractive power being disposed
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`between the first lens element and an imaged object, the first
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`lens element being the only lens element with refractive
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`power in the first lens group; and a second lens group com-
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`prising, in order from the object side to the image side: a
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`FIG. 1 shows an imaging optical lens assembly in accor-
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`dance with a first embodiment of the present invention.
`FIG. 2 shows the aberration curves ofthe first embodiment
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`of the present invention.
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`FIG. 3 shows an imaging optical lens assembly in accor-
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`dance with a second embodiment of the present invention.
`FIG. 4 shows the aberration curves of the second embodi-
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`ment of the present invention.
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`FIG. 5 shows an imaging optical lens assembly in accor-
`dance with a third embodiment of the present invention.
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`FIG. 6 shows the aberration curves ofthe third embodiment
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`of the present invention.
`FIG. 7 is TABLE 1 which lists the optical data of the first
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`embodiment.
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`FIG. 8 is TABLE 2 which lists the aspheric surface data of
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`the first embodiment.
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`FIG. 9 is TABLE 3 which lists the optical data ofthe second
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`embodiment.
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`FIG. 10 is TABLE 4 which lists the aspheric surface data of
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`the second embodiment.
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`FIG. 11 is TABLE 5 which lists the optical data of the third
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`embodiment.
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`FIG. 12 is TABLE 6 which lists the aspheric surface data of
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`the third embodiment.
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`FIG. 13 is TABLE 7 which lists the data of the respective
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`embodiments resulted from the equations.
`DETAILED DESCRIPTION OF THE PREFERRED
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`EMBODIMENTS
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`The present invention provides an imaging optical lens
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`assembly including, in order from the object side to the image
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`side: a first lens group comprising a first lens element with
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`positive refractive power, no lens element with refractive
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`power being disposed between the first lens element and an
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`imaged object, the first lens element being the only lens
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`element with refractive power in the first lens group; and a
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`second lens group comprising, in order from the object side to
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`the image side: a second lens element with negative refractive
`power; a third lens element; and a fourth lens element;
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`wherein focusing is performed by moving the first lens ele-
`ment along the optical axis, such that as a distance between
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`the imaged object and the imaging optical lens assembly
`changes from far to near, a distance between the first lens
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`APPL—1024 / Page 18 of 23
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`APPL-1024 / Page 18 of 23
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`element and the imaging surface changes from near to far; and
`wherein the number of the lens elements with refractive
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`power in the imaging optical lens assembly is N, and it satis-
`fies the relation: 4§N§5
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`When the relation of N:5 is satisfied, the fifth lens element
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`can be disposed between the first and second lens elements,
`the third and fourth lens elements, or the fourth lens element
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`and the image plane.
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`In the aforementioned imaging optical lens assembly, the
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`focal length ofthe imaging optical lens assembly is fwhen the
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`first lens element is positioned closest to the image plane, the
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`focal length of the first lens element is fl, the focal length of
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`the third lens element is f3, and they satisfy the relations:
`1.0<f/f1<1.7, 0.6<f/f3<1.8.
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`When f/fl satisfies the above relation, the displacement
`distance ofthe first lens element will not be too large, thus the
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`total track length (TTL) of the imaging optical lens assembly
`will not become too long. This also ensures that the move-
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`ment of the first lens element relative to the image plane has
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`enough sensitivity required for focusing adjustment. By hav-
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`ing the first lens element move along the optical axis to
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`perform the focusing adjustment
`(the so-called internal
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`focusing method), the total track length ofthe imaging optical
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`lens assembly can be shortened effectively. TTL is defined as
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`the on-axis spacing between the obj ect-side surface ofthe first
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`lens element and the image plane when the first lens element
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`is positioned closest to the imaged object.
`The relation 0.6<f/f3<l .8 enables the third lens element to
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`effectively distribute the refractive power of the optical sys-
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`tem, reducing the sensitivity of the optical system.
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`In the aforementioned imaging optical lens assembly, the
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`on-axis spacing between the image-side surface of the first
`lens element and the image plane is Dl when the first lens
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`element is positioned closest to the imaged object, the on-axis
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`spacing between the image-side surface of the first lens ele-
`ment and the image plane is D2 when the first lens element is
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`positioned closest to the image plane, the focal length of the
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`imaging optical lens assembly is fwhen the first lens element
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`is positioned closest to the image plane, and they satisfy the
`relation: 1 .0<(D 1 —D2) * 100/f<3 .0.
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`When the above relation is satisfied, the movement of the
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`first lens element relative to the image plane has enough
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`sensitivity required for focusing adjustment. The above rela-
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`tion also prevents the displacement distance of the first lens
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`element from becoming too large.
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`In the aforementioned imaging optical lens assembly, the
`on-axis spacing between the third lens element and the fourth
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`lens element is T34, the on-axis spacing between the second
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`lens element and the third lens element is T23, and they
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`satisfy the relation: 0.2<T34/T23<l .6.
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`When the above relation is satisfied, the off-axis aberration
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`of the imaging optical lens assembly can be effectively cor-
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`rected. The above relation also prevents the back focal length
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`from becoming too short and thus causing the rear end of the
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`lens assembly to have insufficient space to accommodate
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`mechanical components.
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`In the aforementioned imaging optical lens assembly, the
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`maximum focal length ofthe imaging optical lens assembly is
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`fmax, the minimum focal length of the imaging optical lens
`60
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`assembly is fmm, and they satisfy the relation: 1211,10,]
`51.05.
`f
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`The above relation prevents the displacement distance of
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`the first lens element from becoming too large and keeps the
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`magnifying power of the optical system within a proper
`range.
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`In the aforementioned imaging optical lens assembly, the
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`back focal length of the imaging optical lens assembly is
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`4
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`BFLl when the first lens element is positioned closest to the
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`imaged object, the back focal length of the imaging optical
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`lens assembly is BFL2 when the first lens element is posi-
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`tioned closest to the image plane, and they satisfy the relation:
`IBFLl—BFL2I<O.1 mm.
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`Preferably, BFLl and BFL2 satisfy the relation: IBFLl—
`BFL2|:0.
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`When the above relation is satisfied, the image plane can be
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`fixed and the number of moving elements can be reduced,
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`thereby reducing the cost and the variability in the manufac-
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`turing of the lens assembly.
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`In the aforementioned imaging optical lens assembly, it is
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`preferable that the first lens element has a convex obj ect-side
`surface so that the refractive power thereofcan be enhanced to
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`shorten the total track length of the imaging optical lens
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`assembly.
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`In the aforementioned imaging optical lens assembly, it is
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`preferable that the fourth lens element has a concave image-
`side surface.
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`In the aforementioned imaging optical lens assembly, it is
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`preferable that the second lens element has a concave image-
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`side surface and the third lens element has a concave object-
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`side surface and a convex image-side surface, so that accu-
`mulation of aberrations can be avoided.
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`In the present imaging optical lens assembly, the first lens
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`element provides a positive refractive power, and the aperture
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`stop is located near the object side of the imaging optical lens
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`assembly, thereby the exit pupil of the imaging optical lens
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`assembly can be positioned far away from the image plane.
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`Therefore, the light will be projected onto the electronic
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`sensor at a nearly perpendicular angle, and this is the telecen-
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`tric feature of the image side. The telecentric feature is very
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`important to the photosensitive power of the current solid-
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`state electronic sensor as it can improve the photosensitivity
`ofthe electronic sensor to reduce the probability ofthe occur-
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`rence of shading.
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`In addition, in optical systems with a wide field ofview, the
`correction of distortion and chromatic aberration of magnifi-
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`cation is especially necessary, and the correction can be made
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`by placing the aperture stop in a location where the refractive
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`power of the optical system is balanced. In the present imag-
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`ing optical lens assembly, if the aperture stop is disposed
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`between the first lens element and the imaged object, the
`telecentric feature will be enhanced to reduce the total track
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`length of the optical system; if the aperture stop is disposed
`between the first lens element and the second lens element,
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`the wide field ofview is emphasized. Such an arrangement of
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`the aperture stop also effectively reduces the sensitivity ofthe
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`optical system.
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`In the present imaging optical lens assembly, the lens ele-
`ments can be made of glass or plastic material. If the lens
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`elements are made of glass, there is more flexibility in dis-
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`tributing the refractive power of the optical system. If plastic
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`material is adopted to produce lens elements, the production
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`cost will be reduced effectively. Additionally, the surfaces of
`the lens elements can be formed to be aspheric and ma