Anamorphic converter

• US 20040196570A1
• Filed: 03/30/2004
• Published: 10/07/2004
• Est. Priority Date: 04/04/2003
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Nurishi, Ryuji
• Granted Patent: US 6,995,920 B2
• Time in Patent Office: Days
• US Class Current: 359/668
• CPC Class Codes: G02B 13/08 Anamorphotic objectives

Abstract

To obtain an anamorphic converter of the rear converter system which is especially most suitable for a converter for the cinema and excellent in optical performance, and in which an effective image surface of an imaging optical system can be sufficiently utilized. The anamorphic converter includes at least an anamorphic lens disposed on an image side of an imaging optical system, and in the anamorphic converter, when a focal length conversion magnification in an arbitrary cross section X containing an optical axis of the anamorphic converter is assigned βx, a focal length conversion magnification in a cross section Y containing an optical axis and being perpendicular to the cross section X is assigned βy, an aspect ratio of an image pickup range in an image surface of the imaging optical system is assigned AR1, and an aspect ratio of an effective area of image pickup means is assigned AR2, the following relationship is established:

0.9<(AR1×βx)/(AR2×βy)<1.1

Claims

1. An anamorphic converter comprising at least an anamorphic lens disposed on an image side of an imaging optical system,

wherein when a focal length conversion magnification in an arbitrary cross section X containing an optical axis of the anamorphic converter is assigned β

x, a focal length conversion magnification in a cross section Y containing an optical axis and being perpendicular to the cross section X is assigned β

y, an aspect ratio of an image pickup range in an image surface of the imaging optical system is assigned AR1, and an aspect ratio of an effective area of image pickup means is assigned AR2, the following relationship is established;

 

 

0.9<

(AR1 ×

β

x)/(AR2×

β

y)<

1.1

2. An anamorphic converter according to claim 1, wherein the anamorphic lens is provided within an afocal group.

3. An anamorphic converter according to claim 1, wherein both β

x and β

y are positive values, and the anamorphic converter has positive refracting powers in the cross section X and in the cross section Y.

4. An anamorphic converter according to claim 3, further comprising, from the imaging optical system side in a stated order, a first group of lenses having a negative refracting power, a second group of lenses including at least two or more anamorphic lenses, and a third group of lenses having a positive refracting power.

5. An anamorphic converter according to claim 3, wherein the following relationship is established:

1≦

(AR2²+1)×

β

y²/(AR1²+1)>

2.6

6. An anamorphic converter according to claim 1, wherein both β

x and β

y are negative values, and the anamorphic converter further comprises at least one negative lens and two or more anamorphic lenses.

8. (currently amended) A lens device, comprising:

the anamorphic converter as claimed in claim 1 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

9. (currently amended) An image pickup device, comprising:

the anamorphic converter as claimed in claim 1

an imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

17. A lens device, comprising:

the anamorphic converter as claimed in claim 2 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

18. A lens device, comprising:

the anamorphic converter as claimed in claim 3 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

19. A lens device, comprising:

the anamorphic converter as claimed in claim 4 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

20. A lens device, comprising:

the anamorphic converter as claimed in claim 5 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

21. A lens device, comprising:

the anamorphic converter as claimed in claim 6 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

23. An image pickup device, comprising:

the anamorphic converter as claimed in claim 2

an imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

24. An image pickup device, comprising:

the anamorphic converter as claimed in claim 3

an imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

25. An image pickup device, comprising:

the anamorphic converter as claimed in claim 4

an imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

26. An image pickup device, comprising:

the anamorphic converter as claimed in claim 5

an imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

27. An image pickup device, comprising:

the anamorphic converter as claimed in claim 6

an imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

7. An anamorphic converter comprising at least an anamorphic lens disposed on an image side of an imaging optical system,

wherein when a focal length conversion magnification in an arbitrary cross section X containing an optical axis of the anamorphic converter is assigned β

x, and a focal length conversion magnification in a cross section Y containing an optical axis and being perpendicular to the cross section X is assigned β

y, both fix and β

y are negative values.

22. A lens device, comprising:

the anamorphic converter as claimed in claim 7 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

28. An image pickup device, comprising:

the anamorphic converter as claimed in claim 7

an imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

10. An anamorphic converter comprising at least an anamorphic lens disposed on an image side of an imaging optical system,

wherein when a focal length conversion magnification in an arbitrary cross section X containing an optical axis of the anamorphic converter is assigned β

x, a focal length conversion magnification in a cross section Y containing an optical axis and being perpendicular to the cross section X is assigned β

y, an aspect ratio of an image pickup range in an image surface of the imaging optical system is assigned AR1, and an aspect ratio of an effective area of image pickup means is assigned AR2, the following relationships are established;

0.9<

(AR1×

β

x)/(AR2×

β

y)<

1.1 (AR2²+1)×

β

y²/(AR1²+1)<

1

11. An anamorphic converter according to claim 10, wherein the anamorphic lens is provided within an afocal group.

12. An amorphic converter according to claim 10, wherein both fix β

x and β

y are positive values, and the anamorphic converter has positive refracting powers in the cross section X and in the cross section Y.

13. An anamorphic converter according to claim 12, further comprising, from the imaging optical system side in a stated order, a first group of lenses having a negative refracting power, a second group of lenses including at least two or more anamorphic lenses, and a third group of lenses having a positive refracting power.

14. An anamorphic converter according to claim 10, wherein both β

x and β

y are negative values, and the anamorphic converter further comprises at least one negative lens and two or more anamorphic lenses.

15. A lens device, comprising:

the anamorphic converter as claimed in;

claim 10 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

16. An image pickup device, comprising:

the anamorphic converter as claimed in claim 10

the imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

29. A lens device, comprising:

the anamorphic converter as claimed in claim 11 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

30. A lens device, comprising:

the anamorphic converter as claimed in claim 12 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

31. A lens device, comprising:

the anamorphic converter as claimed in claim 13 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

32. A lens device, comprising:

the anamorphic converter as claimed in claim 14 and

the imaging optical system disposed on an object side with respect to the anamorphic converter.

33. An image pickup device, comprising:

the anamorphic converter as claimed in claim 11

the imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

34. An image pickup device, comprising:

the anamorphic converter as claimed in claim 12

the imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

35. An image pickup device, comprising:

the anamorphic converter as claimed in claim 13 the imaging optical system disposed on an object side with respect to the

anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.

36. An image pickup device, comprising:

the anamorphic converter as claimed in claim 14

the imaging optical system disposed on an object side with respect to the anamorphic converter; and

image pickup means disposed on the object side with respect to the anamorphic converter.