Lens system, optical device with lens system, and method of manufacturing lens system
AssigneeNikon Corporation
InventorSayako Yamamoto
Life of this patent
Estimating the term…
Abstract
A lens system comprises, on a side closest to an object, a first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object; and on a side closest to an image, a cemented lens constructed by cementing together a positive lens and a negative lens in order from the object; wherein the lens system satisfies the following conditional expressions: (n1+n2)/2>1.49 (ν1+ν2)/2>60 where n1 and ν1 denote a refractive index and an Abbe number of the first lens component at d-line, respectively, and n2 and ν2 denote a refractive index and an Abbe number of the second lens component at d-line, respectively.
Claims14
A lens system comprising:
- on a side closest to an object, a first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object;
- and
- on a side closest to an image, a cemented lens constructed by cementing together a positive lens and a negative lens in order from the object;
- wherein the lens system satisfies the following conditional expressions:
- (n1+n2)/2>1.49
- (ν1+ν2)/2>60
- where n1 and ν1 denote a refractive index and an Abbe number of the first lens component at d-line, respectively, and n2 and ν2 denote a refractive index and an Abbe number of the second lens component at d-line, respectively, and further comprising:
- a front-side negative lens component having a negative refractive power, an aperture stop, a rear-side negative lens component having a negative refractive power, and a rear-side positive lens component having a positive refractive power in order from the object between the second lens component and the cemented lens.
A method of manufacturing a lens system, the method comprising the steps of:
- arranging, on a side closest to an object, a first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object;
- and
- arranging, on a side closest to an image, a cemented lens constructed by cementing together a positive lens and a negative lens in order from the object;
- wherein the lens system satisfies the following conditional expressions:
- (n1+n2)/2>1.49
- (ν1+ν2)/2>60
- where n1 and ν1 denote a refractive index and an Abbe number of the first lens component at d-line, respectively, and n2 and ν2 denote a refractive index and an Abbe number of the second lens component at d-line, respectively, and
- wherein the lens system further comprises a front-side negative lens component having a negative refractive power, an aperture stop, a rear-side negative lens component having a negative refractive power, and a rear-side positive lens component having a positive refractive power in order from the object between the second lens component and the cemented lens.
Dependencies are inferred from the claim text.