US20160091699A1 - Zoom lens - Google Patents
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- US20160091699A1 US20160091699A1 US14/551,778 US201414551778A US2016091699A1 US 20160091699 A1 US20160091699 A1 US 20160091699A1 US 201414551778 A US201414551778 A US 201414551778A US 2016091699 A1 US2016091699 A1 US 2016091699A1
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/143—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only
- G02B15/1435—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative
- G02B15/143507—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative arranged -++
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
- G02B15/177—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a negative front lens or group of lenses
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/04—Reversed telephoto objectives
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
Definitions
- the present invention relates to a lens, and more particularly to a zoom lens.
- Image capture device such as a camera
- Camera lens is used to capture object-side images through camera lens and image sensing components thereof, wherein the camera lens is configured to focus light beams from object side on the image sensing components.
- Camera lens can be divided into prime lens and zoom lens. Because of being able to adjust a focal length, the zoom lens is more convenient to use.
- a good zoom lens is defined to have great imaging qualities in each focal length. Thus, it is a big challenge to a zoom lens designer to design a zoom lens having good imaging qualities in each focal length.
- the physical characteristics of a zoom lens are related to a temperature change and accordingly the imaging qualities of the zoom lens may be affected by a temperature change. Therefore, the temperature factor must be considered when a zoom lens is being designed, thereby preventing the zoom lens from having imaging qualities varying with temperature.
- One object of the present invention is to provide a zoom lens having an imaging quality not being easily affected by temperatures changes.
- the present invention provides a zoom lens, which includes a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power.
- the second lens group is disposed between the first lens group and the third lens group.
- the second lens group includes at least one aspheric glass lens.
- the first lens group includes a first lens, a second lens and a third lens arranged sequentially.
- the first lens has negative refractive power
- the second lens has negative refractive power
- third lens has positive refractive power.
- the second lens group includes a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged sequentially.
- the fourth lens has positive refractive power
- the fifth lens has positive refractive power
- the sixth lens has negative refractive power
- the seventh lens has positive refractive power.
- the third lens is disposed between the second lens and the fourth lens.
- the third lens group includes an eighth lens having positive refractive power.
- the fourth lens, the fifth lens and the seventh lens are aspheric glass lenses.
- the second lens includes a first surface and a second surface.
- the first surface faces to the first lens and the second surface faces to the third lens.
- a focal length of the first surface is f121
- a focal length of the second surface is f122
- an effective thickness of the center of the second lens is Teff, and 10 ⁇
- the fourth lens includes a third surface which faces to the third lens.
- a focal length of the third surface is f211
- an effective focal length of the second lens group is FG2
- an effective focal length from the fourth lens to the sixth lens of the second lens group is FL456, and 1.06 ⁇ FL456/FG2 ⁇ 1.12.
- the zoom lens further includes an aperture stop which is disposed between the third lens and the fourth lens.
- the zoom lens zooms from a width angle end to a telephoto end
- the first lens group is fixed without a movement
- the second lens group and the third lens group move away from each other
- the aperture stop moves with the second lens group.
- the zoom lens zooms from the telephoto end to the width angle end
- the first lens group is fixed without a movement
- the second lens group and the third lens group move toward each other, and the aperture stop moves with the second lens group.
- the second lens and the eighth lens are aspheric lenses.
- the fourth lens, the fifth lens, the sixth lens and the seventh lens are glass lenses.
- the second lens includes a first surface, a second surface and a reflective surface.
- the first surface faces to the first lens
- the second surface faces to the third lens
- the reflective surface is disposed between the first surface and the second surface.
- the zoom lens of the present invention can have qualified imaging quality under any whether condition.
- FIG. 1A is a schematic structural view of a zoom lens at a width angle end in accordance with an embodiment of the present invention
- FIG. 1B is a schematic structural view of a zoom lens at a middle position in accordance with an embodiment of the present invention
- FIG. 1C is a schematic structural view of a zoom lens at a telephoto end in accordance with an embodiment of the present invention
- FIG. 2A is a field curvature diagram of a zoom lens zooming to a width angle end in accordance with an embodiment of the present invention
- FIG. 2B is a distortion diagram of a zoom lens zooming to a width angle end in accordance with an embodiment of the present invention
- FIG. 2C is a longitudinal aberration diagram of a zoom lens zooming to a width angle end in accordance with an embodiment of the present invention
- FIG. 3A is a field curvature diagram of a zoom lens zooming at a middle position in accordance with an embodiment of the present invention
- FIG. 3B is a distortion diagram of a zoom lens zooming at a middle position in accordance with an embodiment of the present invention.
- FIG. 3C is a longitudinal aberration diagram of a zoom zooming lens at a middle position in accordance with an embodiment of the present invention.
- FIG. 4A is a field curvature diagram of a zoom lens zooming to a telephoto end in accordance with an embodiment of the present invention
- FIG. 4B is a distortion diagram of a zoom lens zooming to a telephoto end in accordance with an embodiment of the present invention
- FIG. 4C is a longitudinal aberration diagram of a zoom lens zooming to a telephoto end in accordance with an embodiment of the present invention.
- FIG. 5 is a schematic structural view of a zoom lens at a width angle end in accordance with an embodiment of the present invention.
- FIGS. 1A-1C are schematic structural views of a zoom lens at a width angle end, a middle position and a telephoto end in accordance with an embodiment of the present invention, respectively.
- the zoom lens 100 in the present embodiment includes a first lens group 110 having negative refractive power, a second lens group 120 having positive refractive power, and a third lens group 130 having positive refractive power.
- the second lens group 120 is disposed between the first lens group 110 and the third lens group 130 , the first lens group 110 is disposed close to an object side, and the third lens group 130 is disposed close to an image side.
- the second lens group 120 functions as a variator group and the third lens group 130 functions as a compensator group; wherein the effective focal length of the zoom lens 100 is related to the position of the second lens group 120 relative to the first lens group 110 and the refraction power of the second lens group 120 .
- the zoom lens 100 may further include an aperture stop 140 disposed between the first lens group 110 and the second lens group 120 .
- FIGS. 1A-1C Please refer to FIGS. 1A-1C .
- the zoom lens 100 zooms from the width angle end (as illustrated in FIG. 1A ) to the middle position (as illustrated in FIG. 1B ) or from the middle position to the telephoto end (as illustrated in FIG. 1C )
- the first lens group 110 is fixed without a movement
- the second lens group 120 and the third lens group 130 move away from each other
- the aperture stop 140 moves with the second lens group 120 .
- the zoom lens 100 zooms from the telephoto end (as illustrated in FIG. 1C ) to the middle position (as illustrated in FIG. 1B ) or from the middle position to the width angle end (as illustrated in FIG. 1A )
- the first lens group 110 is fixed without a movement
- the second lens group 120 and the third lens group 130 move toward each other
- the aperture stop 140 moves with the second lens group 120 .
- the first lens group 110 may include a first lens 111 , a second lens 112 and a third lens 113 arranged sequentially from the object side to the image side.
- the first lens 111 has negative refractive power
- the second lens 112 has negative refractive power
- third lens 113 has positive refractive power.
- the second lens group 120 may include a fourth lens 121 , a fifth lens 122 , a sixth lens 123 and a seventh lens 124 arranged sequentially from the object side to the image side.
- the fourth lens 121 has positive refractive power
- the fifth lens 122 has positive refractive power
- the sixth lens 123 has negative refractive power
- the seventh lens 124 has positive refractive power.
- the third lens 113 is disposed between the second lens 112 and the fourth lens 121 .
- the third lens group 130 may include an eighth lens 131 having positive refractive power.
- the aperture stop 140 is disposed between the third lens 113 and the fourth lens 121 , and is, for instance, close to the fourth lens 121 .
- the surfaces S1 and S2 are two surfaces of the first lenses 111 .
- the surfaces S3 and S4 are two surfaces of the second lenses 112 .
- the surfaces S5 and S6 are two surfaces of the third lens 113 .
- the surface S7 is the aperture stop 140 .
- the surfaces S8 and S9 are two surfaces of the fourth lens 121 .
- the surfaces S10 and S11 are two surfaces of the fifth lens 122 .
- the surfaces S 12 and S13 are two surfaces of the sixth lens 123 .
- the surfaces S14 and S15 are two surfaces of the seventh lens 124 .
- the surfaces S16 and S17 are two surfaces of the eighth lens 131 .
- the “Interval” in Table 2 denotes the straight line distance between one surface and its respective adjacent surface on the optical axis 150 of the zoom lens 100 .
- the interval of the surface S1 denotes a straight line distance between the surface S1 and the surface S2 on the optical axis 150 .
- the interval of the surface S17 denotes a straight line distance between the surface S17 and an imaging surface S18 on the optical axis 150 .
- the surfaces S6, S15 and S17 have variable intervals. Please refer to Table 4 for the specific values of the variable intervals of the surfaces S6, S15 and S17.
- the material of the second lens group 120 is, for instance, glass and the second lens group 120 includes at least one aspheric glass lens.
- the fourth lens 121 , the fifth lens 122 , the sixth lens 123 and the seventh lens 124 are glass lenses; wherein the fourth lens 121 , the fifth lens 122 and the seventh lens 124 are aspheric glass lenses.
- the present invention is not limited to the amount of aspheric glass lenses in the second lens group 120 .
- the impact degree of the temperature change on the imaging position of the zoom lens 100 is effectively reduced due to that the coefficient of linear thermal expansion of common plastic materials is several times higher than that of glass materials thereby causing the change of the radius of curvature of the common plastic materials is several times higher than that of glass materials with the temperature change, the index of refraction of glass aspheric lens is less sensitive to temperature change, and the second lens group 120 functioning as variator group is an important factor for an imaging position of the zoom lens 100 . Therefore, the zoom lens 100 in this embodiment is adapted to all kinds of weather conditions and has qualified imaging qualities without being easily affected by temperature changes.
- the surface S3 of the second lens 112 faces to the first lens 111 and the surface S4 faces to the third lens 112 .
- the focal length of the surface S3 is f121 and the focal length of the surface S4 is f122.
- the focal lengths f121, f122 may be limited to 1.1 ⁇ f121/f122 ⁇ 1.3 in one embodiment.
- the effective thickness of the center of the second lens 112 is Teff and the effective thickness Teff may be limited to 10 ⁇
- the surface S8 of the fourth lens 121 faces to the third lens 113 .
- the focal length of the surface S8 is f211.
- the effective focal length of the second lens group 120 is FG2.
- the focal length f211 and the effective focal length FG2 may be limited to 0.7 ⁇ f211/FG2 ⁇ 0.8.
- the effective focal length from the fourth lens 121 to the sixth lens 123 is FL456.
- the effective focal length FL456 may be limited to 1.06 ⁇ FL456/FG21 ⁇ 0.12.
- the first lens group 110 and the third lens group 130 each may include one aspheric glass lens in one embodiment.
- the second lens 112 and the eighth lens 131 are aspheric lenses, which may be made of glass or plastic.
- the shapes of the surfaces S3 and S4 of the second lens 112 , the surfaces S8 and S9 of the fourth lens 121 , the surfaces S 10 and S11 of the fifth lens 122 , the surfaces S14 and S15 of the seventh lens 124 and the surfaces S16 and S17 of the eighth lens 131 satisfy the following aspheric equation:
- Z(h) denotes the sag in the direction of the optical axis 150
- r denotes the radius of curvature close to the optical axis 150 (as shown in Table 2)
- k denotes a conic constant
- h denotes an aspheric height (the distance from the center to the edge of the lens)
- each one of C 2 , C 4 , C 6 , C 8 , C 10 , C 12 , C 14 , C 16 . . . denotes an aspheric coefficient.
- Table 5 for the detailed parameter values.
- FIGS. 2A, 2B and 2C are field curvature, distortion and longitudinal aberration diagrams of a zoom lens zooming to a width angle end in accordance with an embodiment of the present invention, respectively.
- FIGS. 3A, 3B and 3C are field curvature, distortion and longitudinal aberration diagrams of a zoom lens zooming to a middle position in accordance with an embodiment of the present invention, respectively.
- FIGS. 4A, 4B and 4C are field curvature, distortion and longitudinal aberration diagrams of a zoom lens zooming to a telephoto end in accordance with an embodiment of the present invention, respectively.
- all the obtained curve lines are within a standard range, thus, the zoom lens 100 in this embodiment can have good imaging quality.
- FIG. 5 is a schematic structural view of a zoom lens at a width angle end in accordance with an embodiment of the present invention.
- the zoom lens 100 a in this embodiment can function as a periscope zoom lens and has structure and advantages similar to that of the aforementioned zoom lens 100 ; thus, only the main difference between the zoom lens 100 a and the zoom lens 100 will be described as follow.
- the second lens 112 a of the first lens group 110 a includes the surfaces S3, S4 and a reflective surface S19. Specifically, the surface S3 faces to the first lens 111 , the surface S4 faces to the third lens 113 , and the reflective surface S19 is disposed between the surfaces S3 and S4.
- the reflective surface S19 is configured to change the light path, so that the zoom lens 100 a can function as a periscope zoom lens.
- the angle between the reflective surface S 19 and the optical axis 150 passing through the first lens 110 is, for instance, 45 degrees; so that the optical axis 150 can have a 90-degree turn via the reflective surface S19.
- the angle between the reflective surface S19 and the optical axis 150 passing through the first lens 110 is adjustable and can be adjusted in response to the actual requirements, and the present invention is not limited thereto.
- the parameter values in the above Tables 1 to 5 can be also applied to the zoom lens 100 a in this embodiment; wherein the distance between the surfaces S3 and S4 in Table 1 is referred to the straight line distance between the surface S3 and the reflective surface S19 on the optical axis 150 pulsing the straight line distance between the reflective surface S19 and the surface S4 on the optical axis 150 , as illustrated in FIG. 5 .
- the zoom lens of the present invention has three lens groups. Specifically, while zooming, the first lens group is fixed without a movement, the second and third lens groups move either away from or toward each other, and the aperture stop moves with the second group lens. Because the second lens group includes at least one aspheric glass lens, the zoom lens of the present invention has improved imaging quality due to that the refractive index of a glass lens is less sensitive to temperature changes.
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Abstract
Description
- The present invention relates to a lens, and more particularly to a zoom lens.
- Image capture device, such as a camera, is used to capture object-side images through camera lens and image sensing components thereof, wherein the camera lens is configured to focus light beams from object side on the image sensing components. Camera lens can be divided into prime lens and zoom lens. Because of being able to adjust a focal length, the zoom lens is more convenient to use. A good zoom lens is defined to have great imaging qualities in each focal length. Thus, it is a big challenge to a zoom lens designer to design a zoom lens having good imaging qualities in each focal length.
- Moreover, it is understood that the physical characteristics of a zoom lens are related to a temperature change and accordingly the imaging qualities of the zoom lens may be affected by a temperature change. Therefore, the temperature factor must be considered when a zoom lens is being designed, thereby preventing the zoom lens from having imaging qualities varying with temperature.
- One object of the present invention is to provide a zoom lens having an imaging quality not being easily affected by temperatures changes.
- The present invention provides a zoom lens, which includes a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power. The second lens group is disposed between the first lens group and the third lens group. The second lens group includes at least one aspheric glass lens.
- In one embodiment of the present invention, the first lens group includes a first lens, a second lens and a third lens arranged sequentially. The first lens has negative refractive power, the second lens has negative refractive power, and third lens has positive refractive power. The second lens group includes a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged sequentially. The fourth lens has positive refractive power, the fifth lens has positive refractive power, the sixth lens has negative refractive power, and the seventh lens has positive refractive power. The third lens is disposed between the second lens and the fourth lens. The third lens group includes an eighth lens having positive refractive power.
- In one embodiment of the present invention, the fourth lens, the fifth lens and the seventh lens are aspheric glass lenses.
- In one embodiment of the present invention, the second lens includes a first surface and a second surface. The first surface faces to the first lens and the second surface faces to the third lens. A focal length of the first surface is f121, a focal length of the second surface is f122, and 1.1≦f121/f122≦1.3.
- In one embodiment of the present invention, an effective thickness of the center of the second lens is Teff, and 10≦|f121/Teff|≦11.
- In one embodiment of the present invention, the fourth lens includes a third surface which faces to the third lens. A focal length of the third surface is f211, an effective focal length of the second lens group is FG2, and 0.7≦f211/FG2≦0.8.
- In one embodiment of the present invention, an effective focal length from the fourth lens to the sixth lens of the second lens group is FL456, and 1.06≦FL456/FG2≦1.12.
- In one embodiment of the present invention, the zoom lens further includes an aperture stop which is disposed between the third lens and the fourth lens.
- In one embodiment of the present invention, while the zoom lens zooms from a width angle end to a telephoto end, the first lens group is fixed without a movement, the second lens group and the third lens group move away from each other, and the aperture stop moves with the second lens group. While the zoom lens zooms from the telephoto end to the width angle end, the first lens group is fixed without a movement, the second lens group and the third lens group move toward each other, and the aperture stop moves with the second lens group.
- In one embodiment of the present invention, the second lens and the eighth lens are aspheric lenses.
- In one embodiment of the present invention, the fourth lens, the fifth lens, the sixth lens and the seventh lens are glass lenses.
- In one embodiment of the present invention, the second lens includes a first surface, a second surface and a reflective surface. The first surface faces to the first lens, the second surface faces to the third lens, and the reflective surface is disposed between the first surface and the second surface.
- In summary, because the second lens group of the zoom lens of the present invention includes at least one aspheric glass lens and the refractive index of a glass aspheric lens is less sensitive to a temperature change, the zoom lens of the present invention can have qualified imaging quality under any whether condition.
- The present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
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FIG. 1A is a schematic structural view of a zoom lens at a width angle end in accordance with an embodiment of the present invention; -
FIG. 1B is a schematic structural view of a zoom lens at a middle position in accordance with an embodiment of the present invention; -
FIG. 1C is a schematic structural view of a zoom lens at a telephoto end in accordance with an embodiment of the present invention; -
FIG. 2A is a field curvature diagram of a zoom lens zooming to a width angle end in accordance with an embodiment of the present invention; -
FIG. 2B is a distortion diagram of a zoom lens zooming to a width angle end in accordance with an embodiment of the present invention; -
FIG. 2C is a longitudinal aberration diagram of a zoom lens zooming to a width angle end in accordance with an embodiment of the present invention; -
FIG. 3A is a field curvature diagram of a zoom lens zooming at a middle position in accordance with an embodiment of the present invention; -
FIG. 3B is a distortion diagram of a zoom lens zooming at a middle position in accordance with an embodiment of the present invention; -
FIG. 3C is a longitudinal aberration diagram of a zoom zooming lens at a middle position in accordance with an embodiment of the present invention; -
FIG. 4A is a field curvature diagram of a zoom lens zooming to a telephoto end in accordance with an embodiment of the present invention; -
FIG. 4B is a distortion diagram of a zoom lens zooming to a telephoto end in accordance with an embodiment of the present invention; -
FIG. 4C is a longitudinal aberration diagram of a zoom lens zooming to a telephoto end in accordance with an embodiment of the present invention; and -
FIG. 5 is a schematic structural view of a zoom lens at a width angle end in accordance with an embodiment of the present invention. - The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.
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FIGS. 1A-1C are schematic structural views of a zoom lens at a width angle end, a middle position and a telephoto end in accordance with an embodiment of the present invention, respectively. Please refer toFIG. 1A first. Thezoom lens 100 in the present embodiment includes afirst lens group 110 having negative refractive power, asecond lens group 120 having positive refractive power, and athird lens group 130 having positive refractive power. Thesecond lens group 120 is disposed between thefirst lens group 110 and thethird lens group 130, thefirst lens group 110 is disposed close to an object side, and thethird lens group 130 is disposed close to an image side. In this embodiment, thesecond lens group 120 functions as a variator group and thethird lens group 130 functions as a compensator group; wherein the effective focal length of thezoom lens 100 is related to the position of thesecond lens group 120 relative to thefirst lens group 110 and the refraction power of thesecond lens group 120. Moreover, thezoom lens 100 may further include anaperture stop 140 disposed between thefirst lens group 110 and thesecond lens group 120. - Please refer to
FIGS. 1A-1C . While thezoom lens 100 zooms from the width angle end (as illustrated inFIG. 1A ) to the middle position (as illustrated inFIG. 1B ) or from the middle position to the telephoto end (as illustrated inFIG. 1C ), thefirst lens group 110 is fixed without a movement, thesecond lens group 120 and thethird lens group 130 move away from each other, and theaperture stop 140 moves with thesecond lens group 120. Alternatively, while thezoom lens 100 zooms from the telephoto end (as illustrated inFIG. 1C ) to the middle position (as illustrated inFIG. 1B ) or from the middle position to the width angle end (as illustrated inFIG. 1A ), thefirst lens group 110 is fixed without a movement, thesecond lens group 120 and thethird lens group 130 move toward each other, and theaperture stop 140 moves with thesecond lens group 120. - The
first lens group 110 may include afirst lens 111, a second lens 112 and athird lens 113 arranged sequentially from the object side to the image side. Thefirst lens 111 has negative refractive power, the second lens 112 has negative refractive power, andthird lens 113 has positive refractive power. Thesecond lens group 120 may include a fourth lens 121, a fifth lens 122, a sixth lens 123 and a seventh lens 124 arranged sequentially from the object side to the image side. The fourth lens 121 has positive refractive power, the fifth lens 122 has positive refractive power, the sixth lens 123 has negative refractive power, and the seventh lens 124 has positive refractive power. Thethird lens 113 is disposed between the second lens 112 and the fourth lens 121. Thethird lens group 130 may include aneighth lens 131 having positive refractive power. Theaperture stop 140 is disposed between thethird lens 113 and the fourth lens 121, and is, for instance, close to the fourth lens 121. - The related parameters of the
zoom lens 100 in one embodiment will be described as follow; however, it is understood that these parameter values are provided for an exemplary purpose only and the present invention is not limited thereto. In other words, these parameter values are merely examples, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. -
TABLE 1 Focal Length (mm) refractive power First lens −6.88 −0.15 Second lens −14.86 −0.07 Third lens 13.63 0.07 First lens group −9.85 −0.10 Fourth lens 6.96 0.14 Fifth lens 14.70 0.07 Sixth lens −5.26 −0.19 Seventh lens 44.03 0.02 Second lens group 8.82 0.11 Eighth lens 10.97 0.09 Third lens group 10.97 0.09 -
TABLE 2 Radius of Refractive Abbe Surface curvature (mm) Interval (mm) index number S1 58.09 0.4 1.8 43 S2 5.21 1.34 S3 −18.1 5.06 1.5 56 S4 15.36 0.2 S5 22.8 1.18 1.9 24 S6 −22.8 variable interval A S7 infinity 0.08 S8 4.12 0.63 1.6 57 S9 153.4 0.08 S10 6.29 1.28 1.6 57 S11 19.68 0.08 S12 5.43 0.72 1.9 19 S13 2.4 0.68 S14 −56.21 0.68 1.6 57 S15 −18.21 variable interval B S16 −18.25 2.2 1.5 56 S17 −4.6 variable interval C -
TABLE 3 Width Middle Telephoto angle end position end Focal length (mm) 3.6 6.2 9.9 F-number 3 4.4 6.1 Field of view 66° 39° 25° - As shown in
FIGS. 1A-1C , the surfaces S1 and S2 are two surfaces of thefirst lenses 111. The surfaces S3 and S4 are two surfaces of the second lenses 112. The surfaces S5 and S6 are two surfaces of thethird lens 113. The surface S7 is theaperture stop 140. The surfaces S8 and S9 are two surfaces of the fourth lens 121. The surfaces S10 and S11 are two surfaces of the fifth lens 122. The surfaces S 12 and S13 are two surfaces of the sixth lens 123. The surfaces S14 and S15 are two surfaces of the seventh lens 124. The surfaces S16 and S17 are two surfaces of theeighth lens 131. The “Interval” in Table 2 denotes the straight line distance between one surface and its respective adjacent surface on theoptical axis 150 of thezoom lens 100. For example, the interval of the surface S1 denotes a straight line distance between the surface S1 and the surface S2 on theoptical axis 150. The interval of the surface S17 denotes a straight line distance between the surface S17 and an imaging surface S18 on theoptical axis 150. - In Table 2, the surfaces S6, S15 and S17 have variable intervals. Please refer to Table 4 for the specific values of the variable intervals of the surfaces S6, S15 and S17.
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TABLE 4 Width Middle Telephoto angle end position end variable interval A (mm) 7.22 3.58 0.55 variable interval B (mm) 1.2 6.77 11.2 variable interval C (mm) 4.56 2.63 1.21 - In this embodiment, the material of the
second lens group 120 is, for instance, glass and thesecond lens group 120 includes at least one aspheric glass lens. In one embodiment, for example, the fourth lens 121, the fifth lens 122, the sixth lens 123 and the seventh lens 124 are glass lenses; wherein the fourth lens 121, the fifth lens 122 and the seventh lens 124 are aspheric glass lenses. However, it is to be noted that the present invention is not limited to the amount of aspheric glass lenses in thesecond lens group 120. Through implementing the lens 121, the fifth lens 122, the sixth lens 123 and the seventh lens 124 with glass lenses, the impact degree of the temperature change on the imaging position of thezoom lens 100 is effectively reduced due to that the coefficient of linear thermal expansion of common plastic materials is several times higher than that of glass materials thereby causing the change of the radius of curvature of the common plastic materials is several times higher than that of glass materials with the temperature change, the index of refraction of glass aspheric lens is less sensitive to temperature change, and thesecond lens group 120 functioning as variator group is an important factor for an imaging position of thezoom lens 100. Therefore, thezoom lens 100 in this embodiment is adapted to all kinds of weather conditions and has qualified imaging qualities without being easily affected by temperature changes. - In the
zoom lens 100 of this embodiment, the surface S3 of the second lens 112 faces to thefirst lens 111 and the surface S4 faces to the third lens 112. The focal length of the surface S3 is f121 and the focal length of the surface S4 is f122. To make the second lens 112 have specific shape and qualified refractive power, the focal lengths f121, f122 may be limited to 1.1≦f121/f122≦1.3 in one embodiment. Furthermore, to make thezoom lens 100 have proper overall thickness, the effective thickness of the center of the second lens 112 is Teff and the effective thickness Teff may be limited to 10≦|f121/Teff|≦11. - In this embodiment, the surface S8 of the fourth lens 121 faces to the
third lens 113. The focal length of the surface S8 is f211. The effective focal length of thesecond lens group 120 is FG2. To make thefourth lens 113 have qualified refractive power, the focal length f211 and the effective focal length FG2 may be limited to 0.7≦f211/FG2≦0.8. The effective focal length from the fourth lens 121 to the sixth lens 123 is FL456. To make the lens in thesecond lens group 120 have qualified combined refractive power, the effective focal length FL456 may be limited to 1.06≦FL456/FG21≦0.12. - Furthermore, besides the fourth lens 121, the fifth lens 122 and the seventh lens 124 are aspheric glass lenses, the
first lens group 110 and thethird lens group 130 each may include one aspheric glass lens in one embodiment. For example, as shown in Table 5, the second lens 112 and theeighth lens 131 are aspheric lenses, which may be made of glass or plastic. The shapes of the surfaces S3 and S4 of the second lens 112, the surfaces S8 and S9 of the fourth lens 121, the surfaces S 10 and S11 of the fifth lens 122, the surfaces S14 and S15 of the seventh lens 124 and the surfaces S16 and S17 of theeighth lens 131 satisfy the following aspheric equation: -
- where Z(h) denotes the sag in the direction of the
optical axis 150, r denotes the radius of curvature close to the optical axis 150 (as shown in Table 2), k denotes a conic constant, h denotes an aspheric height (the distance from the center to the edge of the lens), each one of C2, C4, C6, C8, C10, C12, C14, C16 . . . denotes an aspheric coefficient. Please refer to Table 5 for the detailed parameter values. -
TABLE 5 surface k C2 C4 C6 C8 C10 C12 C14 C16 S3 −14.79 0 −3.84E−04 −5.83E−05 1.61E−05 −5.08E−07 −2.37E−07 3.11E−08 −1.17E−09 S4 16.15 0 −9.22E−04 −1.31E−04 4.89E−05 −1.02E−05 1.09E−06 −5.63E−08 9.69E−10 S8 −0.92 0 −6.62E−03 1.01E−03 −2.70E−03 8.51E−04 1.28E−04 −8.54E−05 1.17E−05 S9 477.3 0 −0.02 1.91E−04 5.51E−04 2.13E−04 5.59E−05 −4.61E−05 8.05E−06 S10 0 0 −4.30E−03 8.19E−04 1.05E−03 6.51E−04 −3.69E−04 6.46E−05 −4.39E−06 S11 0 0 0.02 −5.35E−04 2.79E−04 −4.57E−04 4.67E−04 −1.34E−04 1.01E−05 S14 0 0 0.03 3.12E−03 −4.54E−03 3.35E−03 −1.18E−03 2.07E−04 −1.33E−05 S15 0 0 0.01 8.36E−04 −1.15E−03 3.45E−04 2.00E−04 −1.31E−04 2.35E−05 S16 52.31 0 −3.48E−03 −7.39E−05 −7.29E−05 −1.85E−05 1.59E−05 −3.51E−06 2.53E−07 S17 1.2 0 −3.68E−05 −2.76E−04 1.85E−04 −6.49E−05 1.29E−05 −1.31E−06 5.40E−08 - The optical simulation results obtained by the
zoom lens 100 zooming to the width angle end, the middle position and the telephoto end will be described as follow. -
FIGS. 2A, 2B and 2C are field curvature, distortion and longitudinal aberration diagrams of a zoom lens zooming to a width angle end in accordance with an embodiment of the present invention, respectively.FIGS. 3A, 3B and 3C are field curvature, distortion and longitudinal aberration diagrams of a zoom lens zooming to a middle position in accordance with an embodiment of the present invention, respectively.FIGS. 4A, 4B and 4C are field curvature, distortion and longitudinal aberration diagrams of a zoom lens zooming to a telephoto end in accordance with an embodiment of the present invention, respectively. As shown inFIGS. 2A to 4C , all the obtained curve lines are within a standard range, thus, thezoom lens 100 in this embodiment can have good imaging quality. -
FIG. 5 is a schematic structural view of a zoom lens at a width angle end in accordance with an embodiment of the present invention. Please refer toFIG. 5 . Thezoom lens 100 a in this embodiment can function as a periscope zoom lens and has structure and advantages similar to that of theaforementioned zoom lens 100; thus, only the main difference between thezoom lens 100 a and thezoom lens 100 will be described as follow. In thezoom lens 100 a of this embodiment, thesecond lens 112 a of thefirst lens group 110 a includes the surfaces S3, S4 and a reflective surface S19. Specifically, the surface S3 faces to thefirst lens 111, the surface S4 faces to thethird lens 113, and the reflective surface S19 is disposed between the surfaces S3 and S4. The reflective surface S19 is configured to change the light path, so that thezoom lens 100 a can function as a periscope zoom lens. In one embodiment, the angle between the reflective surface S 19 and theoptical axis 150 passing through thefirst lens 110 is, for instance, 45 degrees; so that theoptical axis 150 can have a 90-degree turn via the reflective surface S19. However, the angle between the reflective surface S19 and theoptical axis 150 passing through thefirst lens 110 is adjustable and can be adjusted in response to the actual requirements, and the present invention is not limited thereto. Moreover, it is understood that the parameter values in the above Tables 1 to 5 can be also applied to thezoom lens 100 a in this embodiment; wherein the distance between the surfaces S3 and S4 in Table 1 is referred to the straight line distance between the surface S3 and the reflective surface S19 on theoptical axis 150 pulsing the straight line distance between the reflective surface S19 and the surface S4 on theoptical axis 150, as illustrated inFIG. 5 . - In summary, the zoom lens of the present invention has three lens groups. Specifically, while zooming, the first lens group is fixed without a movement, the second and third lens groups move either away from or toward each other, and the aperture stop moves with the second group lens. Because the second lens group includes at least one aspheric glass lens, the zoom lens of the present invention has improved imaging quality due to that the refractive index of a glass lens is less sensitive to temperature changes.
- While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
Claims (15)
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TW103133239 | 2014-09-25 | ||
TW103133239A | 2014-09-25 | ||
TW103133239A TWI521237B (en) | 2014-09-25 | 2014-09-25 | Zoom lens |
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US9291805B1 US9291805B1 (en) | 2016-03-22 |
US20160091699A1 true US20160091699A1 (en) | 2016-03-31 |
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US14/551,778 Expired - Fee Related US9291805B1 (en) | 2014-09-25 | 2014-11-24 | Zoom lens |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2018077267A (en) * | 2016-11-07 | 2018-05-17 | キヤノン株式会社 | Zoom lens and imaging apparatus having the same |
GB2617672A (en) * | 2022-02-18 | 2023-10-18 | Canon Kk | Zoom lens and image pickup apparatus |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
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CN106772966A (en) * | 2017-01-16 | 2017-05-31 | 东莞市宇瞳光学科技股份有限公司 | A kind of small volume resolution zoom lens high |
KR102395178B1 (en) * | 2019-12-17 | 2022-05-06 | 삼성전기주식회사 | Imaging Lens System |
WO2022056727A1 (en) * | 2020-09-16 | 2022-03-24 | 欧菲光集团股份有限公司 | Optical system, camera module, and electronic device |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
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JP3433734B2 (en) | 2000-03-29 | 2003-08-04 | ミノルタ株式会社 | Imaging lens device |
JP4285957B2 (en) | 2002-08-29 | 2009-06-24 | オリンパス株式会社 | Zoom lens and electronic imaging apparatus having the same |
KR100745510B1 (en) * | 2005-12-15 | 2007-08-02 | 삼성테크윈 주식회사 | Compact zoom lens |
JP4916198B2 (en) * | 2006-03-20 | 2012-04-11 | 株式会社リコー | Zoom lens, imaging device having zoom lens, camera device, and portable information terminal device |
TWI427319B (en) | 2010-09-21 | 2014-02-21 | Optronics Technology Inc A | Miniature zoom lens |
CN102455492A (en) * | 2010-10-15 | 2012-05-16 | 广圆光电股份有限公司 | Minitype zoom lens |
US8587876B2 (en) * | 2010-11-17 | 2013-11-19 | Olympus Imaging Corp. | Zoom lens having optical path bending member and image pickup apparatus equipped with same |
US8218244B2 (en) | 2010-11-22 | 2012-07-10 | A-Optronics Technology Inc. | Miniature zoom lens |
CN102998780B (en) * | 2011-09-09 | 2015-07-22 | 佳能企业股份有限公司 | Zoom lens set |
JP2014235190A (en) * | 2013-05-30 | 2014-12-15 | オリンパスイメージング株式会社 | Zoom lens and imaging device having the same |
-
2014
- 2014-09-25 TW TW103133239A patent/TWI521237B/en not_active IP Right Cessation
- 2014-11-24 US US14/551,778 patent/US9291805B1/en not_active Expired - Fee Related
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2015
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2018077267A (en) * | 2016-11-07 | 2018-05-17 | キヤノン株式会社 | Zoom lens and imaging apparatus having the same |
GB2617672A (en) * | 2022-02-18 | 2023-10-18 | Canon Kk | Zoom lens and image pickup apparatus |
Also Published As
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US9291805B1 (en) | 2016-03-22 |
TW201612581A (en) | 2016-04-01 |
TWI521237B (en) | 2016-02-11 |
CN106199935A (en) | 2016-12-07 |
CN106199935B (en) | 2018-12-28 |
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