Zoom lens, and camera incorporating such zoom lens
First Claim
Patent Images
1. A zoom lens system comprising:
- a first lens unit having positive optical power, said first lens unit being not moved for zooming; and
a second lens unit having negative optical power, said second lens unit being disposed on a rearward side of said first lens unit, and being moved for zooming;
wherein said first lens unit has a cemented surface convex toward a forward side, and a diffractive optical portion is provided on said cemented surface.
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Abstract
Disclosed is a zoom lens system which uses a diffractive optical element such that high optical performance can be obtained over the overall power variation range. The zoom lens system includes a first lens unit having positive optical power, and a second lens unit having negative optical power and disposed on a rearward side of the first lens unit. A diffractive optical portion is provided on a cemented surface, which is convex toward a forward side, in the first lens unit or the second lens unit.
21 Citations
23 Claims
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1. A zoom lens system comprising:
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a first lens unit having positive optical power, said first lens unit being not moved for zooming; and
a second lens unit having negative optical power, said second lens unit being disposed on a rearward side of said first lens unit, and being moved for zooming;
wherein said first lens unit has a cemented surface convex toward a forward side, and a diffractive optical portion is provided on said cemented surface. - View Dependent Claims (2, 21)
a zoom lens system recited in claim 1; and
an opto-electric converting element for receiving an image formed by said zoom lens system.
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3. A zoom lens system comprising:
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a first lens unit having positive optical power; and
a second lens unit having negative optical power, said second lens unit being disposed on a rearward side of said first lens unit, and being moved for zooming;
wherein said first lens unit has a cemented surface convex toward a forward side, a diffractive optical portion is provided on said cemented surface, and a following condition is satisfied, - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 22)
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12. A zoom lens system comprising:
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a first lens unit having positive optical power; and
a second lens unit having negative optical power, said second lens unit being disposed on a rearward side of said first lens unit, and being moved for zooming;
wherein said second lens unit has a cemented surface convex toward a forward side, and a diffractive optical portion is provided on said cemented surface. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 23)
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14. A zoom lens system according to claim 12, wherein a following condition is satisfied,
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15. A zoom lens system according to claim 12, further comprising a third lens unit disposed on a rearward side of said second lens unit.
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16. A zoom lens system according to claim 12, further comprising a third lens unit having positive optical power, said third lens unit being disposed on a rearward side of said second lens unit;
- and a fourth lens unit having positive optical power, said fourth lens unit being disposed on a rearward side of said third lens unit.
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17. A zoom lens system according to claim 16, wherein said first lens unit, said second lens unit, said third lens unit, and said fourth lens unit are moved for zooming.
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18. A zoom lens system according to claim 16, wherein said first lens unit, and said third lens unit are not moved for zooming, and said fourth lens unit is moved for zooming.
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19. A zoom lens system according to claim 12, wherein a following condition is satisfied,
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20. A zoom lens system according to claim 12, wherein said zoom lens forms an image on an opto-electric converting element.
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23. A camera comprising:
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a zoom lens system recited in claim 12; and
an opto-electric converting element for receiving an image formed by said zoom lens system.
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Specification