Electronic picture taking apparatus having a zoom lens system

• US 6,785,056 B2
• Filed: 09/04/2003
• Issued: 08/31/2004
• Est. Priority Date: 07/10/2000
• Status: Expired due to Term

• Current Assignee: OM Digital Solutions Corporation
• Original Assignee: Olympus Corporation
• Inventors: Mihara, Shinichi
• Primary Examiner(s): Schwartz, Jordan M.
• Application Number:
  US10/654,470
• Publication Number:
  US 20040051962A1
• Time in Patent Office: 362 Days
• Field of Search: 359/686, 359/680-682, 359/684, 359/676
• US Class Current: 359/686
• CPC Class Codes: G02B 15/144515 arranged -+++
• CPC Class Codes: G02B 15/177 having a negative front lens or group of lenses
• CPC Class Codes: G02B 26/023 comprising movable attenuating elements, e.g. neutral density filters

Abstract

An electronic picture taking apparatus comprises a zoom lens system and an image pickup device. The zoom lens system has a type of movement suitable for stable, high performance in the range from infinite to near distance and having a reduced thickness. The zoom lens system comprises at least four lens units. A foremost first lens unit on the object side of said zoom lens system has a negative refractive power. Each of three consecutive lens units has variable space on the image side thereof between an adjacent lens unit for performing a zooming operation. A rearmost lens unit of the zoom lens system consists of a single positive lens element having an aspherical surface and being fixed during the zooming operation. The zoom lens system includes an aperture stop moving incorporated with the second lens unit which is adjacent to the first lens unit.

Claims

1. An electronic picture taking apparatus comprising a zoom lens system and an electronic image pickup device;

said zoom lens system comprising a first negative lens unit, a second positive lens unit, a third positive lens unit, and a fourth positive lens unit in order from an object side,

a space between said second lens unit and third lens unit increasing during a zooming operation from a wide angle end to a telephoto end while focused on an infinite object;

focusing on the object nearer the zoom lens system being performed by moving said third lens unit toward the object side;

said fourth lens unit consisting of a single positive lens element having an aspherical surface; and

said zoom lens system satisfying the condition

4. An electronic picture taking apparatus according to claim 1, wherein said first lens unit includes in order from the object side, a negative subunit consisting of two negative lens elements and a positive subunit consisting of a single positive lens element.

7. An electronic picture taking apparatus according to claim 1, wherein said first lens unit consists of, in order from the object side, a negative lens component having less than three negative lens elements, and a positive lens component having a positive lens element, and

at least one negative lens element in said negative lens component has an aspherical surface.

13. An electronic picture taking apparatus according to claim 1, further comprising a near-infrared light blocking thin film having spectral transmittance of more than 80% at a wavelength of 600 nm and less than 10% at a wavelength of 700 nm on an optical path to said image pickup device.

16. An electronic picture taking apparatus according to claim 13, further comprising a color encoding filter array including complementary color elements provided on the image receiving area of said image pickup device.

19. An electronic picture taking apparatus according to claim 16, wherein said color encoding filter array includes a substantially similar number of at least four different colors of said filter elements, and said filter elements are arranged in a mosaic pattern such that the same color elements are not adjacent to each other.

22. An electronic picture taking apparatus according to claim 16, wherein said color encoding filter array includes green, yellow, cyan, and magenta color filter elements,

said green filter element has a peak of spectral transmittance at a wavelength GP,

said yellow filter element has a peak of spectral transmittance at a wavelength YP,

said cyan filter element has a peak of spectral transmittance at a wavelength CP,

said magenta filter element has two peaks of spectral transmittance at wavelengths MP1 and MP2, and

wherein said GP, YP, CP, MP1, and MP2 satisfy the conditions

25. An electronic picture taking apparatus according to claim 22, each of said green, yellow and cyan filter elements has a spectral transmittance at a wavelength of 530 nm of more than 80% of said peak spectral transmittance thereof, and

said magenta filter element has a spectral transmittance at a wavelength of 530 nm between 10% and 50%, inclusive, of the larger peak spectral transmittance of said two peak spectral transmittances thereof.

28. An electronic picture taking apparatus according to claims 1, further comprising an optical low-pass filter on an optical path to said image pickup device that has a thickness tLPF satisfying the condition

31. An electronic picture taking apparatus according claim 1, further comprising a stop member having a plurality of fixed sized openings,

said plurality of fixed sized openings are alternatively insertable into an optical path between said first lens unit and said third lens unit to adjust an illuminance of an image formed by said zoom lens system.

34. An electronic picture taking apparatus according to claim 31, wherein one of said plurality of openings has transmittance at a wavelength of 550 nm of more than 80% and another one of said plurality of openings is equipped with a medium which has transmittance at a wavelength of 550 nm of less than 80%.

37. An electronic picture taking apparatus according to claim 34, when an effective F-number Fno′

is defined by Fno′

=f/(ID×

SQRT(T)), the illuminance of the image such that Fno′

is greater than a/0.4 μ

m is adjusted by inserting said opening equipped with the medium which has transmittance at a wavelength of 550 nm of less than 80% into the optical path,

where f is a focal length of said zoom lens system, ID is a diameter of an opening, T is the transmittance of an opening, a is a pitch between adjacent pixel elements of said image pickup device, and SQRT means square root.

40. A picture taking apparatus according to claim 31, wherein each of said plurality of openings is equipped with a spatial frequency filter having a different spatial frequency response from each of the others.

2. An electronic picture taking apparatus comprising a zoom lens system and an electronic image pickup device;

said zoom lens system comprising a first negative lens unit, a second positive lens unit, a third positive lens unit, and a fourth positive lens unit in the order from an object side;

a space between said second lens unit and said third lens unit increasing during a zooming operation from a wide angle end to a telephoto end while focused on an infinite object;

focusing on the object nearer the zoom lens system being performed by moving said third lens unit toward the object side;

said second lens unit consisting of, in order from the object side, a single lens element having an aspherical surface and a cemented lens component composed of a positive lens element and a negative lens element in this order from the object side;

said third lens unit consisting of a single positive lens element; and

said zoom lens system satisfying the condition

5. An electronic picture taking apparatus according to claim 2, wherein said first lens unit includes in order from the object side, a negative subunit consisting of two negative lens elements and a positive subunit consisting of a single positive lens element.

8. An electronic picture taking apparatus according to claim 2, wherein said first lens unit consists of, in order from the object side, a negative lens component having less than three negative lens elements, and a positive lens component having a positive lens element, and

at least one negative lens element in said negative lens component has an aspherical surface.

10. An electronic picture taking apparatus according to claim 2, wherein said first and second lens unit satisfy the condition

11. An electronic picture taking apparatus according to claim 2, wherein said first and second lens unit satisfy the condition

14. An electronic picture taking apparatus according to claim 2, further comprising a near-infrared light blocking thin film having spectral transmittance of more than 80% at a wavelength of 600 nm and less than 10% at a wavelength of 700 nm on an optical path to said image pickup device.

17. An electronic picture taking apparatus according to claim 14, further comprising a color encoding filter array including complementary color elements provided on the image receiving area of said image pickup device.

20. An electronic picture taking apparatus according to claim 17, wherein said color encoding filter array includes a substantially similar number of at least four different colors of said filter elements, and said filter elements are arranged in a mosaic pattern such that the same color elements are not adjacent to each other.

23. An electronic picture taking apparatus according to claim 17, wherein said color encoding filter array includes green, yellow, cyan, and magenta color filter elements,

said green filter element has a peak of spectral transmittance at a wavelength GP,

said yellow filter element has a peak of spectral transmittance at a wavelength YP,

said cyan filter element has a peak of spectral transmittance at a wavelength CP,

said magenta filter element has two peaks of spectral transmittance at wavelengths MP1 and MP2, and

wherein said GP, YP, CP, MP1, and MP2 satisfy the conditions

26. An electronic picture taking apparatus according to claim 23, each of said green, yellow and cyan filter elements has a spectral transmittance at a wavelength of 530 nm of more than 80% of said peak spectral transmittance thereof, and

said magenta filter element has a spectral transmittance at a wavelength of 530 nm between 10% and 50%, inclusive, of the larger peak spectral transmittance of said two peak spectral transmittances thereof.

29. An electronic picture taking apparatus according to claims 2, further comprising an optical low-pass filter on an optical path to said image pickup device that has a thickness tLPF satisfying the condition

32. An electronic picture taking apparatus according claim 2, further comprising a stop member having a plurality of fixed sized openings,

said plurality of fixed sized openings are alternatively insertable into an optical path between said first lens unit and said third lens unit to adjust an illuminance of an image formed by said zoom lens system.

35. An electronic picture taking apparatus according to claim 32, wherein one of said plurality of openings has transmittance at a wavelength of 550 nm of more than 80% and another one of said plurality of openings is equipped with a medium which has transmittance at a wavelength of 550 nm of less than 80%.

38. An electronic picture taking apparatus according to claim 35, when an effective F-number Fno′

is defined by Fno′

=f/(ID×

SQRT(T)), the illuminance of the image such that Fno′

is greater than a/0.4 μ

m is adjusted by inserting said opening equipped with the medium which has transmittance at a wavelength of 550 nm of less than 80% into the optical path,

where f is a focal length of said zoom lens system, ID is a diameter of an opening, T is the transmittance of an opening, a is a pitch between adjacent pixel elements of said image pickup device, and SQRT means square root.

41. A picture taking apparatus according to claim 32, wherein each of said plurality of openings is equipped with a spatial frequency filter having a different spatial frequency response from each of the others.

3. An electronic picture taking apparatus comprising a zoom lens system and an electronic image pickup device;

said zoom lens system comprising a first negative lens unit, a second positive lens unit, a third positive lens unit, and a fourth positive lens unit in order from an object side;

a space between said second lens unit and third lens unit increasing during a zooming operation from a wide angle end to a telephoto end while focused on an infinite object,

focusing on the object nearer the zoom lens system being performed by moving said third lens unit toward the object side,

said second lens unit consisting of, in order from an object side, a lens component having an aspherical surface and a negative lens component,

said third lens unit consisting of a single positive lens element, and

said zoom lens system satisfying the condition

6. An electronic picture taking apparatus according to claim 3, wherein said first lens unit includes in order from an object side, a negative subunit consisting of two negative lens elements and a positive subunit consisting of a single positive lens element.

9. An electronic picture taking apparatus according to claim 3, wherein said first lens unit consists of, in order from the object side, a negative lens component having less than three negative lens elements, and a positive lens component having a positive lens element, and

at least one negative lens element in said negative lens component has an aspherical surface.

12. An electronic picture taking apparatus according to claim 3, wherein said first and second lens unit satisfy the condition

15. An electronic picture taking apparatus according to claim 3, further comprising a near-infrared light blocking thin film having spectral transmittance of more than 80% at a wavelength of 600 nm and less than 10% at a wavelength of 700 nm on an optical path to said image pickup device.

18. An electronic picture taking apparatus according to claim 15, further comprising a color encoding filter array including complementary color elements provided on the image receiving area of said image pickup device.

21. An electronic picture taking apparatus according to claim 18, wherein said color encoding filter array includes a substantially similar number of at least four different colors of said filter elements, and said filter elements are arranged in a mosaic pattern such that the same color elements are not adjacent to each other.

24. An electronic picture taking apparatus according to claim 18, wherein said color encoding filter array includes green, yellow, cyan, and magenta color filter elements,

said green filter element has a peak of spectral transmittance at a wavelength GP,

said yellow filter element has a peak of spectral transmittance at a wavelength YP,

said cyan filter element has a peak of spectral transmittance at a wavelength CP,

said magenta filter element has two peaks of spectral transmittance at wavelengths MP1 and MP2, and

wherein said GP, YP, CP, MP1, and MP2 satisfy the conditions

27. An electronic picture taking apparatus according to claim 24, each of said green, yellow and cyan filter elements has a spectral transmittance at a wavelength of 530 nm of more than 80% of said peak spectral transmittance thereof, and

said magenta filter element has a spectral transmittance at a wavelength of 530 nm between 10% and 50%, inclusive, of the larger peak spectral transmittance of said two peak spectral transmittances thereof.

30. An electronic picture taking apparatus according to claims 3, further comprising an optical low-pass filter on an optical path to said image pickup device that has a thickness tLPF satisfying the condition

33. An electronic picture taking apparatus according claim 3, further comprising a stop member having a plurality of fixed sized openings,

said plurality of fixed sized openings are alternatively insertable into an optical path between said first lens unit and said third lens unit to adjust an illuminance of an image formed by said zoom lens system.

36. An electronic picture taking apparatus according to claim 33, wherein one of said plurality of openings has transmittance at a wavelength of 550 nm of more than 80% and another one of said plurality of openings is equipped with a medium which has transmittance at a wavelength of 550 nm of less than 80%.

39. An electronic picture taking apparatus according to claim 36, when an effective F-number Fno′

is defined by Fno′

=f/(ID×

SQRT(T)), the illuminance of the image such that Fno′

is greater than a/0.4 μ

m is adjusted by inserting said opening equipped with the medium which has transmittance at a wavelength of 550 nm of less than 80% into the optical path,

where f is a focal length of said zoom lens system, ID is a diameter of an opening, T is the transmittance of an opening, a is a pitch between adjacent pixel elements of said image pickup device, and SQRT means square root.

42. A picture taking apparatus according to claim 33, wherein each of said plurality of openings is equipped with a spatial frequency filter having a different spatial frequency response from each of the others.

43. An electronic picture taking apparatus comprising a zoom lens system and an image pickup device;

said zoom lens system consisting of, in order from an object side, a first negative lens unit, a second positive lens unit, a third positive lens unit, and a fourth positive lens unit,

focusing on the object nearer the zoom lens system being performed by moving said third lens unit toward the object side,

said fourth lens unit consisting of a single lens element having an aspherical surface and kept fixed during a zooming operation.

46. An electronic picture taking apparatus according to claim 43, wherein said first lens unit moves during zooming.

49. An electronic picture taking apparatus according to claim 43, wherein one of the second, third and fourth positive lens units moves monotonically toward the object side during zooming from a wide angle end to a telephoto end.

50. An electronic picture taking apparatus according to claim 43, wherein the second and the third positive lens units move monotonically toward the object side during zooming from a wide angle end to a telephoto end.

51. An electronic picture taking apparatus according to claim 49, wherein the first negative ions unit moves during zooming.

52. An electronic picture taking apparatus according to claim 50, wherein the first negative lens unit moves during zooming.

44. An electronic picture taking apparatus comprising a zoom lens system and an image pickup device;

said zoom lens system consisting of, in order from an object side, a first negative lens unit, a second positive lens unit, a third positive lens unit, and a fourth positive lens unit,

focusing on the object nearer the zoom lens system being performed by moving said third lens unit toward the object side,

said second lens unit consisting of a single lens element having an aspherical surface and a cemented lens component composed of, in order from the object side, a positive lens element and a negative lens element,

said third lens unit consisting of a single positive lens element.

47. An electronic picture taking apparatus according to claims 44, wherein said first lens unit moves during zooming.

45. An electronic picture taking apparatus comprising a zoom lens system and an image pickup device;

said zoom lens system consisting of, in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a positive refractive power and a fourth lens unit having a positive refractive power,

said second lens unit consisting of a positive lens component having an aspherical surface and a negative lens component,

said third lens unit consisting of a positive lens element,

wherein said third lens unit moves toward the object side when focusing in close range of the zoom lens system.

48. An electronic picture taking apparatus according to claim 45, wherein said first lens unit moves during zooming.