JP2011102838A5

JP2011102838A5 -

Info

Publication number: JP2011102838A5
Application number: JP2009256911A
Authority: JP
Filing date: 2009-11-10
Publication date: 2012-12-20
Anticipated expiration: 2029-11-10

Description

このような目的を達成するため、本発明を例示する第一の態様に従えば、物体側より順に並んだ、全体として正の屈折力を有する第１レンズ群と、第２レンズ群とから構成され、前記第１レンズ群は、物体側より順に並んだ、物体側に凸面を向けた第１の正レンズと、両凸レンズと、前記両凸レンズに接合されるか又は所定の空気間隔を隔てて配置される第１の負レンズとを有し、前記第２レンズ群は、物体側より順に並んだ、第２の正レンズと、前記第２の正レンズに接合されるか又は所定の空気間隔を隔てて配置される第２の負レンズと、前記第２の負レンズに接合されるか又は所定の空気間隔を隔てて配置される第３の正レンズとを有し、硝材に対するレンズパワーの温度依存係数Ｃ（Ｋ^-1）を、前記硝材の基準波長に対する屈折率をｎとし、前記硝材の基準波長に対する屈折率の温度依存係数をｄｎ/ｄＴ（Ｋ^-1）とし、前記硝材の線膨張係数をα（Ｋ^-1）としたとき、次式Ｃ＝｛（１/（ｎ−１））・ｄｎ/ｄＴ｝−α で表すとき、前記第１の正レンズの硝材に対するレンズパワーの温度依存係数Ｃ ₁は、次式Ｃ ₁＞１５×１０^-6（Ｋ^-1）の条件を満たし、前記両凸レンズの硝材に対するレンズパワーの温度依存係数Ｃ ₂（Ｋ^-1）は、次式Ｃ ₂＜-２０×１０^-6（Ｋ^-1）の条件を満たすことを特徴とする色消しアサーマルレンズ系が提供される。 In order to achieve such an object, according to the first aspect illustrating the present invention, the first lens group having a positive refractive power as a whole and arranged in order from the object side and the second lens group are configured. The first lens group is arranged in order from the object side and is joined to the first positive lens having a convex surface facing the object side, a biconvex lens, and the biconvex lens , or separated by a predetermined air interval. and a disposed first negative lens is, the second lens group, arranged in order from the object side, a second positive lens, or a predetermined air gap is bonded to the second positive lens a second negative lens disposed at a, and a third positive lens that are arranged at spaced or predetermined air gap is bonded to the second negative lens, the lens power for glass material The temperature dependence coefficient C (K ⁻¹ ) is the refractive index with respect to the reference wavelength of the glass material. When n is n, the temperature dependence coefficient of the refractive index with respect to the reference wavelength of the glass material is dn / dT (K ⁻¹ ), and the linear expansion coefficient of the glass material is α (K ⁻¹ ), the following expression C = {(1 / (N−1)) · dn / dT} −α, the temperature dependence coefficient C ₁ of the lens power for the glass material of the first positive lens is expressed by the following formula C ₁ > 15 × 10 ⁻⁶ (K ^{− 1} ) The temperature dependence coefficient C ₂ (K ⁻¹ ) of the lens power for the glass material of the biconvex lens satisfies the condition of the following formula C ₂ <−20 × 10 ⁻⁶ (K ⁻¹ ) A featured achromatic athermal lens system is provided.

Claims

The first lens group having a positive refractive power as a whole, arranged in order from the object side, and a second lens group,
The first lens group is arranged in order from the object side and is joined to the first positive lens having a convex surface facing the object side, a biconvex lens, and the biconvex lens , or arranged at a predetermined air interval. A first negative lens ,
The second lens group, arranged in order from the object side, a second positive lens and a second negative lens disposed second or at a predetermined air gap is joined to the positive lens, and a third positive lens that are arranged at spaced or predetermined air gap is bonded to the second negative lens,
The temperature dependence coefficient C (K ⁻¹ ) of the lens power with respect to the glass material is defined as n as the refractive index with respect to the reference wavelength of the glass material, and dn / dT (K ⁻¹ ) as the temperature dependence coefficient of the refractive index with respect to the reference wavelength of the glass material. When the linear expansion coefficient of the glass material is α (K ⁻¹ ), the following expression C = {(1 / (n−1)) · dn / dT} −α
The temperature dependence coefficient C ₁ of the lens power with respect to the glass material of the first positive lens is expressed by the following equation:
C ₁ > 15 × 10 ⁻⁶ (K ⁻¹ )
Meet the requirements of
The temperature dependence coefficient C ₂ (K ⁻¹ ) of the lens power with respect to the glass material of the biconvex lens is expressed by the following equation:
C ₂ <−20 × 10 ⁻⁶ (K ⁻¹ )
Achromatic athermal lens system characterized by satisfying the following conditions.

The temperature dependence coefficient C ₃ (K ⁻¹ ) of the lens power with respect to the glass material of the third positive lens is expressed by the following equation:
C ₃ > 15 × 10 ⁻⁶ (K ⁻¹ )
The achromatic athermal lens system according to claim 1, wherein:

An optical apparatus comprising the achromatic athermal lens system according to claim 1.