Zoom optical system and electronic system incorporating IT
AssigneeOlympus Corporation
InventorsHiroyuki Minakata, Masaru Ikemachi, Kanato Adachi
Life of this patent
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Abstract
The invention relates to a zoom optical system that makes it possible to offer a sensible tradeoff between cost savings and size reductions and an electronic system that incorporates it. The zoom optical system comprises a lens group having negative refracting power and a lens group having positive refracting power. At least one lens is formed by molding of a first lens blank (11) that provides a surface including at least an optical function surface after molding, and a second lens blank (12) that provides a surface other than said surface including at least an optical function surface after molding, wherein the first lens blank (11) and the second lens blank (12) are integrated into a one-piece lens (10).
Claims3
A zoom optical system consisting only of, in order from an object side, a first lens group having negative refracting power, a second lens group having positive refracting power, a third lens group having negative refracting power and a fourth lens group having positive refracting power, wherein:
- said first lens group consists only of two lenses,
- said fourth lens group consists only of one lens,
- at least one lens is formed by molding of a first lens blank that provides a surface including at least an optical function surface after molding, and a second lens blank that provides a surface other than said surface including at least an optical function surface after molding,
- a cavity is provided in said second lens blank,
- said first lens blank is fitted and located in said cavity,
- said first lens blank and said second lens blank are integrated into a one-piece lens, and
- at least one positive lens in said first lens group satisfies the following condition (2E), and said one-piece lens includes a thinnest portion having a thickness that satisfies the following condition (1):
- 0.1<HH1/Φ1<10 (2E)
- 0.1 mm<t<0.5 mm (1)
- where HH1 is a principal point spacing (mm) of the positive lens in the first lens group, Φ1 is a refracting power of the positive lens in the first lens group, and t is the thickness of the thinnest portion of said one-piece lens.
A zoom optical system consisting only of, in order from an object side, a first lens group having negative refracting power, a second lens group having positive refracting power, a third lens group having negative refracting power and a fourth lens group having positive refracting power, wherein:
- said first lens group consists only of two lenses,
- said fourth lens group consists only of one lens,
- at least one lens is formed by molding of a first lens blank that provides a surface including at least an optical function surface after molding, and a second lens blank that provides a surface other than said surface including at least an optical function surface after molding,
- a cavity is provided in said second lens blank,
- said first lens blank is fitted and located in said cavity,
- said first lens blank and said second lens blank are integrated into a one-piece lens, and
- at least one positive lens in said second lens group satisfies the following condition (3E), and said one-piece lens includes a thinnest portion having a thickness that satisfies the following condition (1):
- 0.1<HH2/Φ2<6 (3E)
- 0.1 mm<t<0.5 mm (1)
- where HH2 is a principal point spacing (mm) of the positive lens in the second lens group, Φ2 is a refracting power of the positive lens in the second lens group, and t is the thickness of the thinnest portion of said one-piece lens.
A zoom optical system consisting only of, in order from an object side, a first lens group having negative refracting power, a second lens group having positive refracting power, a third lens group having negative refracting power and a fourth lens group having positive refracting power, wherein:
- said first lens group consists only of two lenses,
- said fourth lens group consists only of one lens,
- at least one lens is formed by molding of a first lens blank that provides a surface including at least an optical function surface after molding, and a second lens blank that provides a surface other than said surface including at least an optical function surface after molding,
- a cavity is provided in said second lens blank,
- said first lens blank is fitted and located in said cavity,
- said first lens blank and said second lens blank are integrated into a one-piece lens, and
- at least one positive lens in said fourth lens group satisfies the following condition (5E), and said one-piece lens includes a thinnest portion having a thickness that satisfies the following condition (1):
- 0.1<HH4/Φ4<10 (5E)
- 0.1 mm<t<0.5 mm (1)
- where HH4 is a principal point spacing (mm) of the positive lens in the fourth lens group, Φ4 is a refracting power of the positive lens in the fourth lens group, and t is the thickness of the thinnest portion of said one-piece lens.
Dependencies are inferred from the claim text.