US005861999A
`5,861,999
`[11] Patent Number:
`(15
`United States Patent
`Tada
`[45] Date of Patent:
`Jan. 19, 1999
`
`
`[54]
`
`SUPER WIDE ANGEL LENS SYSTEM USING
`AN ASPHERICAL LENS
`
`[75]
`
`Inventor: Eijiroh Tada, Tokyo, Japan
`
`[73] Assignee: Asahi Seimitsu Kabushiki Kaisha,
`Tokyo, Japan
`
`[21] Appl. No.: 915,603
`
`Filed:
`Aug. 21, 1997
`[22]
`Foreign Application Priority Data
`[30]
`Aug, 23,1996
`[JP]
`Japan se eeseesssescssscsseeseeneeeenee 8-222304
`Jul. 28, 1997
`[JP]
`Japan .eececccscseeessecseseeneecsee 9-201903
`
`12/1974 Takahashi
`....sescssssssseeseon 359/751
`3,856,385
`8/1990 Igarashi ....cssessssssesnssesseeoen 359/708
`4,952,040
`
`9/1990 Sato veccecssscsscsssssesssseesssseesseeeese 359/749
`4,957,355
`5,477,388 12/1995 Ishiyamaet al. oo. eee 359/751
`
`Primary Examiner—Scott J. Sugarman
`Attorney, Agent, or Firm—Greenblum & Bernstein, P.L.C.
`
`[57]
`
`ABSTRACT
`
`A retrofocus lype super wide angle lens system includes a
`front lens group of negative power and a rear lens group of
`positive power, arranged in this order from the object side.
`The front lens group consists of a negative meniscus first
`
`Inte CLS caceseseseeene G02B 13/04; Go2B 13/18 © clement with a cones Suriace facing theobjectsideand
`[SE]
`[52] US. Cl.
`_ 359/752: 359/713; 359/753
`a second
`lens element
`havingat least one aspherical surface,
`
`.
`a
`arranged in this order from the object side. The aspherical
`[58] Field of Search .........359/751,752, aaa . second lens elementis shaped such thatit forms a biconcave
`
`[56]
`
`‘
`References Cited
`U.S. PATENT DOCUMENTS
`
`,
`
`°
`
`;
`
`,
`
`lens in the vicinity of the optical axis and forms a negative
`meniscus lens with a convex surface located on the object
`side at a peripheral portion thereof.
`
`3,506,339
`
`4/1970 Kazamaki
`
`..c.cccccsessssseeeseee 359/751
`
`10 Claims, 9 Drawing Sheets
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`U.S. Patent
`
`Jan. 19, 1999
`
`Sheet 1 of 9
`
`5,861,999
`
`FIG. 1
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`10
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`02
`-02
`SPHERICAL
`ABERRATION
`
`02
`-02
`ASTIGMATISM
`
`-30 (%) 30
`DISTORTION
`
`2
`
`

`

`U.S. Patent
`
`Jan. 19, 1999
`
`Sheet 2 of 9
`
`5,861,999
`
`
`
`3
`
`

`

`U.S. Patent
`
`Jan. 19, 1999
`
`Sheet 3 of 9
`
`5,861,999
`
`FIG. 6
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`FIG. 9
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`DISTORTION
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`

`

`U.S. Patent
`
`Jan. 19, 1999
`
`Sheet 4 of 9
`
`5,861,999
`
`FIG. 10A
`
`Y= 0,00
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`g LINE---=2
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`FIG. 10D
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`Y= 1.08 ¢LINE +902
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`5
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`

`

`U.S. Patent
`
`Jan. 19, 1999
`
`Sheet 5 of 9
`
`5,861,999
`
`FIG. 11
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`CHROMATIC
`
`02
`-02
`ASTIGMATISM
`
`-30 (%) 30
`DISTORTION
`
`6
`
`

`

`U.S. Patent
`
`Jan. 19, 1999
`
`Sheet 6 of 9
`
`5,861,999
`
`FIG. 15A
`
`Y= 0.00
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`d LINE
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`FIG. 15C
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`FIG. 15D
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`7
`
`

`

`U.S. Patent
`
`Jan. 19, 1999
`
`Sheet 7 of 9
`
`5,861,999
`
`FIG. 16
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`FIG. 18
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`ABERRATION
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`CHROMATIC
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`ASTIGMATISM
`
`FIG. 19
`
`58.2
`
`-30 (%) 30
`DISTORTION
`
`8
`
`

`

`U.S. Patent
`
`Jan. 19, 1999
`
`Sheet 8 of 9
`
`5,861,999
`
`FIG. 20A
`Y= 0.00
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`FIG. 20C
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`5,861,999
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`U.S. Patent
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`Jan. 19, 1999
`
`10
`
`10
`
`

`

`5,861,999
`
`1
`SUPER WIDE ANGEL LENS SYSTEM USING
`AN ASPHERICAL LENS
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates to a super wide angle lens
`system which can be used for a monitoring camera (CCTV)
`etc.
`
`2. Description of the Related Art
`In general, a super wide angle lens system is used as the
`lens system in a monitoring camera or the like, to view or
`monitor a wide angle range. In order to increase the back
`focal distance and widenthe angle of view,a retrofocus type
`of super wide angle lens having a negative front lens group
`and a positive rear lens group is used. In such a retrofocus
`type, the angle of view can be widened by increasing the
`negative power of the front
`lens group. To this end, a
`plurality of negative lens elements of the rear lens group
`share the negative power. Generally, the negative lens ele-
`ments consist of a negative meniscusfirst lens element with
`a convex surface facing the object side and a negative
`second lens element. The meniscuslens can advantageously
`reduce, due to the shape thereof,
`the astigmatism and
`distortion of a bundle oflight chicfly at a large angle of view.
`It is mainly for this reason that the meniscus lens has been
`used as the negative first lens elementof the frontlens group.
`In a super wide angle lens system having an angle of view
`in the range of 120° to 140° and in which the front lens group
`consists of a negative meniscus first lens element and a
`negative second lens element, the radius of curvature of a
`second concave surface (surface on the image side) of the
`negative meniscus first lens element is reduced (ie., the
`depth of the concave surface is increased). However, this
`makesit very difficult to produce the meniscuslens.If the
`negative powerof the second lens elementis increased, the
`negative power of the first
`lens element
`is reduced.
`Consequently, the radius of curvature of the second surface
`ofthe first lens element is increased. However, if the second
`lens element is made of a biconcave lens to increase the
`
`negative power, an under curvature of field occurs. In order
`to salve this problem, upon design, consideration must be
`given to balance the negative power between the first lens
`element and the second lens element.
`
`SUMMARY OF THE INVENTION
`
`10
`
`15
`
`30
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`11
`
`invention to provide a
`It is an object of the present
`retrofocus type super wide angle lens system in which an
`angle of view of approximately 120° to 140° and an
`F-number of approximately 1.2 to 1.4 can be obtained
`without
`increasing the radius of curvature of a second
`surface of a negative meniscusfirst lens element.
`To achieve the object mentioned above, according to the
`present invention, there is provided a retrofocus type super
`145f,6
`(7)
`wide angle lens system havingafront lens group of negative
`power and a rear lens group of positive power, arranged in
`42 fo955
`(8)
`this order from the object side. The front lens group consists
`of a negative meniscus first lens element with a convex
`surface facing the object side and a second lens element
`having al least one aspherical surface, arrangedin this order
`from the object side. The aspherical second lens elementis
`shaped such that the second lens element forms a biconcave
`lens in the vicinity of the optical axis (for a bundle of rays
`at a small angle of view) and forms a negative meniscus lens
`with a convex surface facing the object side at the peripheral
`portion thereof (for a bundle of rays at a large angle of view).
`
`2
`The boundary portion between the biconcave lens portion
`of the aspherical second lens element in the vicinity of the
`optical axis and the peripheral negative meniscus lens por-
`tion thereof is, for example, located substantially on the
`peripheral portion of the axial bundle defined by the
`F-number.
`
`Preferably, the surface of the second lens element located
`on the object side is made of an aspherical surface and
`preferably satisfies the following conditions:
`
`-125R,/fS-6
`
`2.0x10~7SA/fPS1.0x104
`
`-3.0x10-7SA,/f? S-2.0x10>
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`
`wherein
`
`(1)
`
`(2)
`
`(3)
`
`(4)
`
`R, represents a radius of curvature of the paraxial spheri-
`cal surface of the aspherical surface af the second lens
`clement,
`A, represents a fourth-order aspherical factor of the
`aspherical surface of the second lens element,
`A, represent a sixth-order aspherical factor of the aspheri-
`cal surface of the second lens element,
`Ag represents a eighth-order aspherical factor of the
`aspherical surface of the second lens element,
`f represents a focal length of the whole lens system.
`The aspherical second lens element can be made entirely
`of a plastic mold, or can be made of a hybrid lens having a
`spherical glass lens to which an aspherical plastic layer is
`adhered.
`The rear lens group can be made of various combinations
`of lenses. For instance, the rear lens group can consist of a
`positive single lens element, a diaphragm, and two pairs of
`cemented lenses, each respectively having a positive lens
`element and a negative lens element cemented thereto,
`arranged in this order from the object side. With this
`arrangement, not only can the divergent light emitted from
`the front lens group be effectively received by the rear lens
`group, but also longitudinal chromatic aberration and chro-
`matic aberration of magnification can be compensated for by
`a simple structure.
`The rear lens group can consist of a positive single third
`lens element, a diaphragm, a first cemented lens assembly
`having a negative fourth lens element and a positive fifth
`lens element cemented thereto, and a second cemented lens
`assembly having a negative sixth lens element and a positive
`seventh lens element cemented thereto, arranged in this
`order from the object side. The rear lens group preferably
`satisfies the following conditions:
`
`2.50 SRylf23.10
`
`2.35 ER/fE2.55
`
`(5)
`
`(6)
`
`wherein
`R, represents a radius of curvature of the surface on the
`image side of the fourth lens element,
`R,, represents a radius of curvature of the surface on the
`image side of the sixth lens element,
`f,_5 represents a resultant focal length of the fourth and
`fifth lens elements,
`f4o.42 represents a resultant focal length of the sixth and
`seventh lens elements.
`
`11
`
`

`

`5,861,999
`
`4
`FIG. 20 shows coma diagrams of the super wide angle
`lens system shown in FIG. 16 at each angle of view; and
`FIG. 21 showsa definition of the aspherical amount, etc.,
`of an aspherical lens.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`In a retrofocus type of super wide angle lens system
`according to the present invention, the negative first lens
`group consists of a negative meniscus first lens element
`having a convex surface facing the object side and a second
`lens clement having at Icast onc aspherical surface, arranged
`in this order from the object side. The shapeofthe aspherical
`second lens element is such that it serves as a biconcavelens
`
`3
`In an embodiment of the present invention, the third lens
`element is made of a positive meniscus lens with a convex
`surface on the image side, the fourth lens element is made
`of a negative lens with a concave surface on the imageside,
`the fifth lens element is madeof a positive biconvexlens,the
`sixth lens element is made of a negative meniscus lens with
`a convex surface on the object side, and the seventh lens
`element is made of a positive biconvex lens.
`The present disclosure relates to subject matter contained
`in Japanese Patent Application Nos. 08-222394 (filed on
`Aug. 23, 1996) and 09-201903 (filed on Jul. 28, 1997) which
`are expressly incorporated herein by reference in their
`entireties.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention will be described below in detail with
`reference to the accompanying drawings, in which:
`FIG. 1 is a schematic view showingthe lens arrangement
`of a first embodiment of a super wide angle lens system,
`according to the present invention;
`FIG. 2 shows diagrams of chromatic aberrations repre-
`sented byspherical aberrations, in the super wide angle lens
`system shown in FIG. 1;
`FIG. 3 shows astigmatism diagrams of the super wide
`angle lens system shownin FIG. 1;
`FIG. 4 showsdistortion diagramsof the super wide angle
`lens system shown in ['IG. 1;
`FIG. 5 shows coma diagramsof the super wide angle lens
`system shownin FIG. 1 at each angle of view;
`FIG. 6 is a schematic view showing the lens arrangement
`of a second embodiment of a super wide angle lens system,
`according to the present invention;
`FIG. 7 shows diagrams of chromatic aberrations repre-
`sented byspherical aberrations, in the super wide angle lens
`system shown in FIG. 6;
`FIG. 8 shows astigmatism diagrams of the super wide
`angle lens system shown in FIG. 6;
`FIG. 9 showsdistortion diagramsof the super wide angle
`lens system shown in FIG. 6;
`FIG. 10 shows coma diagrams of the super wide angle
`lens system shown in FIG. 6 at each angle of view;
`FIG. 11 is a schematic view showing the lens arrangement
`of a third embodiment of a super wide angle lens system,
`according to the present invention;
`FIG. 12 shows diagrams of chromatic aberrations repre-
`sented by spherical aberrations, in the super wide angle lens
`system shown in FIG. 11;
`FIG. 13 shows astigmatism diagrams of the super wide
`angle lens system shown in FIG. 11;
`FIG. 14 showsdistortion diagramsof the super wide angle
`lens system shown in FIG. 11;
`FIG. 15 shows coma diagrams of the super wide angle
`lens system shown in FIG. 11 at each angle of view;
`FIG. 16 is a schematic view showing the lens arrangement
`of a fourth embodiment of a super wide angle lens system,
`according to the present invention;
`FIG. 17 shows diagrams of chromatic aberrations repre-
`sented byspherical aberrations, in the super wide angle lens
`system shown in FIG. 16;
`FIG. 18 shows astigmatism diagrams of the super wide
`angle lens system shownin FIG. 16;
`FIG. 19 showsdistortion diagramsof the super wide angle
`lens system shown in FIG. 16;
`
`10
`
`15
`
`30
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`35
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`40
`
`45
`
`50
`
`55
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`60
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`65
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`12
`
`in the vicinity of the optical axis (for a bundle of light at a
`small angle of view) andserves as a negative meniscus lens
`whose convex surface is located on the object side at the
`peripheral portion thereof (for a bundle of light at a large
`angle of view).
`Namely,
`the aspherical second lens element basically
`functions as a biconcave lens having a negative power to
`reduce the negative powerof the meniscusfirst lens element.
`However, if the negative power of the biconcave lens is
`increased, an undercurvature of field occurs. To solve this
`problem, the aspherical second lens element forms at the
`peripheral portion thereof, a negative meniscus lens having
`its convex surface located on the object side. If the aspheri-
`cal second lens element is made of a biaspherical lens, the
`aberrations can be easily compensated.
`It is preferable that the boundary portion between the
`biconcave surface portion of the aspherical second lens
`elementin the vicinity of the optical axis and the peripheral
`negative meniscus lens portion is located substantially on
`the peripheral portion of the axial bundle, determined bythe
`F-number. If the central biconcave portion is smaller than
`the diameter of the peripheral portion of the axial bundle,the
`longitudinal spherical aberration and the chromatic aberra-
`tion are adversely influenced and the aspherical aberration
`factor at the low-order term becomes large. Consequently,
`the change in the sag amountofthe aspherical surface shown
`in FIG. 21 is too large to obtain the surface shape most
`appropriate to correct the off-axis aberrations. If the central
`biconcave portion is larger than the diameter of the periph-
`eral portion of the axial bundle, the effective area of the
`negative meniscus lens element is reduced. Consequently,
`no effective aberration correction occurs.
`
`
`
`Conditions (1) through (4) specify the conditions on the
`aspherical surface (third surface) of the second lens element
`on the object side. Condition (1) specifies the radius of
`curvature of the paraxial spherical surface of the third
`surface of the second lens clementandthe focal length ofthe
`whole optical system.
`If the ratio defined in condition (1) is smaller than the
`lower limit, the radius of curvature ts large and it becomes
`difficult to obtain sufficient back focal distance with respect
`to the focal length. If the ratio exceeds the upper limit, the
`radius of curvature is too small
`to correct
`the off-axis
`aberrations by the aspherical surface.
`Condition (2) specifies the condition on the fourth-order
`aspherical factor of the aspherical surface. If the ratio
`defined in condition (2) is smaller than the lower limit, the
`astigmatism can not be sufficiently compensated.If the ratio
`defined in condition (2) exceeds the upper limit, the sag
`amount from the spherical (third) surface with respect to the
`F-numberof the optical system (axial bundle) is so large that
`the spherical aberration is adversely influenced.
`
`
`
`12
`
`

`

`5
`Consequently, a reduced performance of the center portion
`of the lens occurs.
`
`6
`
`5,861,999
`
`<Embodiment 1>
`FIG. 1 showsa first embodiment of a super wide angle
`lens system according to the present
`invention.
`In this
`Conditions (3) and (4) specify the condition on the
`embodiment, the lens system consists of a front lens group
`sixth-order and eighth-order aspherical
`factors of the
`10 and a rear lens group 20,in this order from the object side
`aspherical surface, respectively. If condition (3) or (4) is not
`(the left side as viewed in FIG. 1). The front lens group 10
`satisfied, the astigmatism increases toward the peripheral
`consists of a first
`lens element 11 made of a negative
`portion of the lens when the angle of viewis large.
`meniscuslens having a convex surface on the object side and
`Conditions (5) through (8) specify the conditions on the
`a second lens element 12 made of a biaspherical lens which
`second lens group. Conditions (5) and (6) specify the radius
`forms a biconcave lens at the center portion thereof and
`of curvature of the surface (8-th surface) of the fourth lens
`forms a negative meniscus lens having a convex surface at
`element on the image side, the radius of curvature of the
`the peripheral portion thereof. Thefirst lens element 11 and
`surface (11-th surface) of the sixth lens element onthe image
`the second lens element 12 are arranged in this order from
`the object side.
`side, and the focal length of the whole lens system.
`The rear lens group 20 consists of a third lens element 21
`Conditions (7) and (8) specify the ratio of the resultant
`madeof a positive meniscus lens having a convex surface on
`focal length of the fourth and fifth lens elements and the
`the imageside, a first cemented lens assembly and a second
`focal length of the whole lens system, and the ratio of the
`cemented lens assembly. The first cemented lens assembly
`resultant focal length of the sixth and seventh lens clements
`comprises a fourth lens element 22 of a biconcave lens and
`and the focal length of the whole lens system, respectively.
`a fifth lens element 23 of a biconvex lens cementedthereto.
`If the ratio defined in condition (7) or(8) is larger than the
`The second cemented lens assembly comprises a sixth lens
`upper limit, the focal length of the whole optical system is
`clement 24 of a negative meniscus lens having a convex
`increased so that the angle of view for the samepicture size
`surface on the object side and a seventh lens element 25 of
`can be reduced.If the ratio defined in the condition (7) or (8)
`a biconvex lens cemented thereto. These lens elements are
`is smaller than the lowerlimil, it becomes difficull lo obtain
`arranged in this order from the object side.
`5
`sufficient back focal distance with respect to the focal length.
`A diaphragmSis provided betweenthe third lens element
`If conditions (7) and(8)are satisfied, but condition (5)is
`21 and the fourth lens element 22. “C” designates a glass
`cover of the CCD.
`not satisfied, the spherical aberration and the longitudinal
`chromatic aberration are enhanced. Thus, the optical perfor-
`mance of the central portion of the image surface is detc-
`riorated. [f an attemptis made to correct these aberrations by
`other lens surfaces, off-axis aberration can not be sufficiently
`corrected.
`
`10
`
`15
`
`30
`
`If the ratio defined in condition (6) is smaller than the
`lowerlimit, an over correction of the chromatic aberration of
`magnification occurs, and the off-axis optical performanceis
`deteriorated. If the ratio defined in condition (6) is larger
`than the upper limit, it is difficult to correct the spherical
`aberrations while satisfying condition (5).
`Numerical examples of a super wide angle lens system of
`the present invention will be discussed below with reference
`to the attached drawings and the following tables.
`In the following tables and diagramsthe d-line, g-line and
`C-line represent the chromatic aberrations represented by
`spherical aberrations at the respective wavelengths, S des-
`ignates the Sagittal rays, M designates the Meridional rays,
`FNo designates the F-number, f designates the focal length,
`W designates the half angle of view, {B designates the back
`focal distance, R designates the radius of curvature, D
`designates the distance between the lens surfaces, Nd des-
`ignates the refractive index of the d-line, and vd designates
`the Abbe numberofthe d-line. The back focal distance refers
`to the reduced distance {B between surface No. 12 and No.
`15.
`
`The rotation symmetrical aspherical surface can be gen-
`erally expressed as follows:
`
`x=Ch?/{14+[1-(14K)C7W?]7}+44h+A 6h°+A8h+
`
`wherein, h represents a height above the axis,
`x represents a distance from a tangent plane of an aspheri-
`cal verlex,
`C represents a curvature of the aspherical vertex (1/1),
`K represents a conic constant,
`A4 represents a fourth-order aspherical factor,
`A6 represents a sixth-order aspherical factor,
`A8 represents an eighth-order aspherical factor,
`A10 represents a tenth-order aspherical factor.
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`13
`
`Numerical data regarding the super wide angle lens
`system shown in FIG. 1 is shown in Table 1 below. The
`surface Nos. 13 and 14 correspond to the surfaces of the
`glass cover C. The surface No. 15 refers to the image pickup
`surface of the CCD.
`FIGS. 2 through 5 showaberration diagramsof the lens
`system shownin FIG. 1.
`
`TABLE1
`
`FNO = 1:1.3
`f= 1.00
`W = 58.9
`£B = 2.70 (=0.422/1.51633 + 2.423)
`
`R
`
`16.361
`2.917
`-7.296
`3.887
`-15.840
`-3.450
`©
`-29.920
`2.549
`-3.963
`4.186
`2.400
`-8.712
`w
`@
`el
`
`D
`
`0.634
`1.940
`1.760
`2.204
`1.436
`0.574
`1.338
`0.317
`2.165
`0.035
`0.317
`1.760
`0.000
`0.422
`2.423
`—
`
`Nd
`
`1.77250
`—
`1.49176
`—
`1.84666
`—
`—_—
`1.84666
`1.51633
`—
`1.84666
`1.77250
`—
`1.51633
`—
`—
`
`Surface
`No.
`
`1
`2
`3*
`4*
`5
`6
`diaphragm
`7
`8
`9
`10
`11
`12
`13
`14
`15
`
`vd
`
`49.6
`—
`57.4
`—
`23.8
`—
`—_—
`23.8
`64.1
`—
`23.8
`49.6
`—
`64.1
`—
`—_—
`
`*designates an aspherical surface with rotation symmetry around the optical
`axis.
`Aspherical Data:
`No.3: K = 0.00, A4 = 0.41500 x 107%, A6 = -0.72169 x 10°°, A8 = 0.10529
`x 10-7, A10 = 0.70513 x 10+
`No.4: K = 0.00, A4 = 0.78424 x 10-*, A6 = -0.13731 x 107, A8 = 0.11514
`x 107+, Al10 = -0.22907 x 10°
`
`The aspherical surface No. 3 of the second lens element
`12 makesit possible to serve as a biconcavelensat the center
`portion thereof and as a negative meniscus lens having a
`convex surface on the object side at the peripheral portion
`
`13
`
`

`

`5,861,999
`
`7
`thereof. The shape, paraxial spherical amount and aspherical
`amount (amount of spherical deviation) of surface No. 3 are
`shown in Table 2 below. The definition of the aspherical
`amount, etc., can be seen in FIG. 21.
`
`Distance from
`optical axis
`0.00000
`0.10000
`0.20000
`0.30000
`0.40000
`0.50000
`0.60000
`0.70000
`0.80000
`0.90000
`1.00000
`1.10000
`1.20000
`1.30000
`1.40000
`1.50000
`1.60000
`1.70000
`1.80000
`1.90000
`2.00000
`2.10000
`2.20000
`
`TABLE 2
`
`Surface figure
`0.000000
`-0.000681
`-0.002676
`-0.005839
`-0.009940
`-0.014668
`-0.019654
`-0.024484
`0.028717
`—0.031901
`—0,033590
`—0.033349
`-0,.030765
`-0,.025440
`0.016994
`-0.005050
`0.010765
`0.030831
`0.055518
`0.085160
`0.119985
`0.160005
`0.204833
`
`Paraxial
`spherical amount
`0.000000
`-0.000685
`-0.002742
`-0.006170
`-0.010973
`-0.017153
`-0.024713
`—0.033658
`—0.043992
`—0,055723
`—0,068856
`—0.083399
`—0.099361
`-0,116751
`—0,135580
`—0,155859
`0.177600
`-0.200817
`-0.225525
`-0.251739
`-0.279476
`-0.308753
`-0.339592
`
`Aspherical
`amount
`0.000000
`0.000004
`0.000066
`0.000331
`0.001034
`0.002485
`0.005059
`0.009174
`0.015276
`0.023822
`0.035266
`0.050049
`0.068596
`0.091311
`0.118586
`0.150809
`0.188365
`0.231648
`0.281043
`0.336898
`0.399460
`0.468759
`0.544425
`
`The inflection points in the Sagittal direction and the
`Meridional direction can be obtained by linear and second-
`order differentials of the surface figure (shape) shown in
`Table 2, respectively.
`<Embodiment 2>
`
`FIG. 6 shows a second embodimentof a super wide angle
`lens system according to the present invention. The basic
`structure of the lens system of the second embodimentis
`substantially the same as that of the first embodiment except
`that the fourth lens element 22 of the second lens group 20
`is madeof a negative meniscus lens having a convex surface
`on the object side. Numerical data regarding the second
`embodimentis shown in Table 3 below. The surface figure,
`paraxial spherical amount and aspherical amount of surface
`No. 3 are shownin Table 4 below. FIGS. 7 through 10 show
`aberration diagrams of the lens system of the second
`embodiment.
`
`TABLE 3
`
`INO = 1:1.3
`f = 1.00
`W = 58.4
`fB = 2.75 (=0.432/1.51633 + 2.467)
`
`Surface
`No.
`R
`D
`Nd
`vd
`
`1
`13.592
`0.360
`1.77250
`49.6
`2
`3.238
`1.619
`_
`_
`3*
`-6.981
`1.799
`1.49176
`57.4
`4*
`3.485
`3.231
`_
`_
`5
`-11.389
`0.648
`1.84666
`23.8
`6
`-4.026
`0.980
`_
`_
`diaphragm
`©
`2.319
`—_—
`—_—
`7
`17.988
`0.324
`1.84666
`23.8
`8
`2.907
`1.439
`1.51633
`64.1
`9
`-5.170
`0.036
`—
`—
`10
`4.050
`0.324
`1.84666
`23.8
`
`10
`
`15
`
`25
`
`30
`
`35
`
`40
`
`45
`
`55
`
`60
`
`65
`
`8
`
`TABLE 3-continued
`
`FNO = 1:1.3
`f = 1.00
`W = 58.4
`
`fB = 2.75 (=0.432/1.51633 + 2.467)
`
`Surface
`No.
`
`11
`12
`13
`14
`15
`
`R
`
`2.479
`-10.343
`©
`w
`a
`
`D
`
`1.691
`0.000
`0.432
`2.467
`—
`
`Nd
`
`1.77250
`_
`1.51633
`_
`—
`
`vd
`
`49.6
`_
`64.1
`_
`—
`
`*designates an aspherical surface with rotation symmetry around the optical
`axis.
`Aspherical Data:
`No.3: K = 0.00, A4 = 0.30330 x 1077, A6 = -0.43125 x 10°°, A8 = 0.46329
`x 10°, A10 = -0.24092 x 107+
`No.4: K = 0.00, A4 = 0.50708 x 10-7, A6 = -0.52255 x 10-7, A8 = 0.34087
`x 10°, A10 = -0.73846 x 10°
`
`Distance from
`optical axis
`0.00000
`0.10000
`0.20000
`0.30000
`0.40000
`0.50000
`0.60000
`0.70000
`0.80000
`0.90000
`1.00000
`1.10000
`1.20000
`1.30000
`1.40000
`1.50000
`1.60000
`1.70000
`1.80000
`1.90000
`2.00000
`2.10000
`2.20000
`2.30000
`2.40000
`2.50000
`
`TABLE 4
`
`Surface figure
`0.000000
`-0.000713
`-0.002817
`—0.006206
`-0.010710
`-0.016099
`—0.022096
`—0.028385
`-0.034629
`-0.040475
`—0.045575
`-0.049591
`-0.052212
`-0.053156
`—0.052183
`—0.049096
`-0.043749
`-0.036047
`—0.025958
`-0.013523
`0.001122
`0.017709
`0.035789
`0.054639
`0.073154
`0.089673
`
`
`
`Paraxial
`spherical amount
`0.000000
`-0.000716
`-0.002866
`-0.006449
`-0.011469
`-0.017929
`-0.025832
`-0.035184
`-0.045990
`-0.058258
`-0.071994
`-0.0872N9
`-0.103910
`-0.122111
`-0.141822
`-0.163056
`-0.185828
`-0.210154
`-0.236049
`-0.263533
`-0.292625
`-0.323346
`-0.355718
`-0.389766
`-0.425517
`-0.462997
`
`Aspherical
`amount
`0.000000
`0.000003
`0.000048
`0.000243
`0.000759
`0.001830
`0.003737
`0.006799
`0.011362
`0.017783
`0.026420
`0.037617
`0.051699
`0.068955
`0.089639
`0.113960
`0.142079
`0.174107
`0.210092
`0.250010
`0.293747
`0.341055
`0.391507
`0.444405
`0.498671
`0.552670
`
`<Embodiment 3>
`
`FIG. 11 showsa third embodiment of a super wide angle
`lens system according to the present invention. The basic
`structure of the lens system of the third embodiment is
`substantially the same as that of the second embodiment.
`Numerical data regarding the third embodiment is shown in
`Table 5 below. The surface figure, paraxial spherical amount
`and aspherical amount of surface No. 3 are shown in Table
`6 below. FIGS. 12 through 15 show aberration diagrams of
`the lens system of the third embodiment.
`
`14
`
`14
`
`

`

`5,861,999
`
`9
`
`TABLE5
`FNO = 1:1.3
`f= 1.00
`W = 58.5
`£B = 2.79 (=0.437/1.51633 + 2.501)
`
`R
`
`11.660
`3.274
`-8.060
`3.032
`-11.339
`-3.881
`cd
`28.148
`3.022
`-4.790
`4.000
`2.425
`-11.318
`©
`wo
`oo
`
`D
`
`0.364
`1.637
`2.485
`3.046
`0.655
`0.546
`2.417
`0.327
`1.455
`0.036
`0.327
`1.637
`0.000
`0.437
`2.501
`—
`
`Nd
`
`1.77250
`—
`1.49176
`—
`1.84666
`—
`_
`1.84666
`1.51633
`—_—
`1.84666
`1.77250
`—_—
`1.51633
`_
`—_—
`
`Surface
`No.
`
`1
`2
`3*
`4*
`5
`6
`diaphragm
`7
`8
`9
`10
`11
`12
`13
`14
`15
`
`vd
`
`49.6
`—
`57.4
`—
`23.8
`—
`_
`23.8
`64.1
`—_—
`23.8
`49.6
`—_—
`64.1
`_
`—
`
`*designates an aspherical surface with rotation symmetry around the optical
`axis.
`Aspherical Data:
`No.3: K = 0.00, A4 = 0.30330 x 10-7, A6 = -0.43125 x 10-7, A8 = 0.46329
`x 10-*, A10 = -0.24092 x 10°¢
`No.4: K = 0.00, A4 = 0.50708 x 10°*, A6 = -0.52255 x 10-7, A8 = 0.34087
`x 1077, A10 = -0.73846 x 10-3
`
`Distance from
`optical axis
`0.00000
`0.10000
`0.20000
`0.30000
`0.40000
`0.50000
`0.60000
`0.70000
`0.80000
`0.90000
`1.00000
`1.10000
`1.20000
`1.30000
`1.40000
`1.50000
`1.60000
`1.70000
`1.80000
`1.90000
`2.00000
`2.10000
`2.20000
`2.30000
`2.40000
`2.50000
`2.60000
`2.70000
`
`TABLE 6
`
`Surface figure
`0.000000
`-0.000618
`-0.002449
`-0.005421
`-0.009418
`-0.014283
`—-0.019826
`-0.025827
`—0.032049
`—0.038241
`0.044148
`-0.049517
`-0.054104
`-0.057680
`—-0.060032
`0.060962
`-0.060294
`-0.057864
`-0.053523
`-0.047133
`-0.038568
`-0.027713
`-0.014479
`0.001185
`0.019254
`0.039585
`0.061843
`0.085399
`
`Paraxial
`spherical amount
`0.000000
`-0.000620
`-0.002482
`-0.005585
`-0.009932
`-0.015524
`0.022364
`-0.030455
`-0.039801
`0.050406
`—-0.062275
`0.075415
`0.089831
`-0.105530
`-0.122519
`0.140808
`-0.160405
`-0.181320
`-0.203563
`-0.227146
`-0.252081
`-0.278381
`-0.306059
`-0.335131
`0.365612
`-0.397520
`0.430872
`—0.465686
`
`Aspherical
`amount
`0.000000
`0.000002
`0.000033
`0.000164
`0.000514
`0.001241
`0.002538
`0.004627
`0.007751
`0.012164
`0.018127
`0.025898
`0.035726
`0.047849
`0.062488
`0.079846
`0.100111
`0.123456
`0.150040
`0.180013
`0.213513
`0.250668
`0.291580
`0.336316
`0.384866
`0.437105
`0.492715
`0.551085
`
`<Embodiment 4>
`FIG. 16 showsa fourth embodimentof a super wide angle
`lens system according to the present invention. The basic
`structure of the lens system of the fourth embodimentis
`substantially the same as that of the second embodiment.
`Numerical data regarding the fourth embodiment is shown
`in Table 7 below. The surface figure, paraxial spherical
`amount and aspherical amount of surface No. 3 are shown
`in Table 8 below. FIGS. 17 through 20 show aberration
`diagrams of the lens system of the fourth embodiment.
`
`10
`
`TABLE 7
`
`FNO =1:1.3
`f= 1.00
`W = 58.1
`£B = 2.90 (=0.422/1.51633 + 2.622)
`
`R
`
`17.000
`2.016
`-10.108
`6.008
`-16.636
`-3,553
`95.609
`2.691
`-3.867
`4.862
`2.512
`-8,951
`w
`w
`2
`
`D
`
`0.500
`1.793
`1.149
`1.950
`1.300
`1.880
`6.300
`2.000
`0.030
`0.300
`1.300
`0.000
`0.422
`2.622
`—
`
`Nd
`
`1.77250
`—
`1.49176
`—
`1.84666
`—
`1.84666
`1.51633
`—
`1.84666
`1.77250
`—
`1.51633
`—
`—
`
`Surface
`No.
`
`1
`2
`3*
`4*
`5
`6
`7
`8
`9
`10
`i
`12
`13
`14
`15
`
`vd
`
`49.6
`—
`57.4
`—
`23.8
`—
`23.8
`64.1
`—
`23.8
`49.6
`—
`64.1
`—
`—
`
`*dcesignates an aspherical surface with rotation symmetry around the optical
`axis.
`Aspherical Data:
`No.3: K = 0.00, A4 = 0.88810 x 10-*, A6 = -0.27110 x 10-*, A8 = 0.79690
`x 10-°, A10 = -0.61180 x 10°*
`No.4: K = 0.00, A4 = 0.11720, A6 = -0.48970 x 107*, A8 = 0.25560 x 10+,
`A10 = -0.13970 x 10-*
`
`TABLE8
`
`Distance from
`optical axis
`
`Surface figure
`
`Paraxial
`spherical amount
`
`Aspherical
`amount
`
`0.00000
`0.10000
`0.20000
`0.30000
`0.40000
`0.50000
`
`0.60000
`0.70000
`0.80000
`0.90000
`1.00000
`1.10000
`1.20000
`1.30000
`1.40000
`1.50000
`1.60000
`1.70000
`1.80000
`
`0.000000
`—0.000618
`-0.002449
`-0,005421
`—0.009418
`0.014283
`
`0.019826
`—0.025827
`0.032049
`—0.038241
`0.044148
`-0.049517
`-0.054104
`-0.057680
`-0.060032
`—0.060962
`-0.060294
`-0.057864
`-0.053523
`
`0.000000
`-0.000620
`-0.002482
`-0,005585
`0.009932
`-0.015524
`
`-0.022364
`-0,030455
`-0.039801
`-0.050406
`-0,062275
`-0.075415
`-0.089831
`-0.105530
`-0.122519
`-0.140808
`-0.160405
`-0.181320
`-0.203563
`
`0.000060
`0.000002
`0.000033
`0.0001 64
`0.000514
`0.001241
`
`0.002538
`0.004627
`0.007751
`0.012164
`0.018127
`0.025898
`0.035726
`0.047849
`0.062488
`0.079846
`0.100111
`0.123456
`0.150040
`
`5
`
`10
`
`15
`
`20
`
`30
`
`35
`
`40
`
`45
`
`50
`
`Values of the ratios defined in conditions (1) through (8)
`55 for the four embodiments are shown in Table 9 below.
`TABLE9
`Embodiment 1
`Embodiment 2
`
`60
`
`65
`
`Condition (1)
`Condition (2)
`Condition (3)
`Condition (4)
`Condition (5)
`Condition (6)
`Condition (7)
`Condition (8)
`
`/
`-7.296
`4.1500 x 107
`-7.2169 x 10%
`1.0529 x 10-3
`2.549
`2.400
`529.729
`4.118
`
`/
`-6.981
`3.0330 x 10~°
`-4,3125 x 10%
`4,6329 x 10-*
`2.907
`2.479
`25.228
`4.178
`
`15
`
`15
`
`

`

`5,861,999
`
`11
`
`TABLE 9-continued
`Embodiment 3
`
`Conditi