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Optical system with wavelength selecting device

a wavelength selection and optical system technology, applied in the field of optical systems with wavelength selection devices, can solve the problems of inability to improve optical performance, inability to meet the requirements of chromatic aberration correction without increasing liable to incur increase in the thickness of lens elements and the number of lens elements, so as to achieve high optical performance, low manufacturing cost, and compact

Inactive Publication Date: 2005-02-10
NIKON CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides an optical system with a wavelength selecting device that can be used in video cameras and electronic still cameras. The wavelength selecting device can be an interference filter or an absorption filter, and it is designed to improve the optical performance of the entire image field. The optical system is compact, light-weight, and low-cost. The technical effects of the invention include having inconspicuous chromatic aberration and high optical performance over the entire image field, being low manufacturing cost, and being light-weight and compact.

Problems solved by technology

On the other hand, chromatic aberration cannot be satisfactory corrected without increasing the number of lens elements.
So, it is not possible to improve optical performance.
However, since these glass materials have low refractive index, it is liable to incur increase in the thickness of lens and in the number of lens elements.
As a result, not only the optical system becomes large, but also it becomes difficult to lower the cost because the material is expensive.
Wherever it is arranged, the total lens length increases by the amount of the thickness of the filter and an increase in the cost is inevitable.

Method used

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Examples

Experimental program
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first embodiment

[First Embodiment]

At first, a first embodiment of the present invention having a wavelength selecting device, precisely described later, is explained below with reference to accompanying drawings. FIG. 1 is a sectional view showing the lens arrangement of an optical system according to Example 1 of a first embodiment of the present invention in a wide-angle end state W and in a telephoto end state T. Various aberrations of the objective optical system OB according to Example 1 of a first embodiment in the wide-angle end state and in the telephoto end state are shown in FIGS. 2 and 3, respectively. As is shown in FIGS. 2 and 3, monochromatic aberrations are satisfactorily corrected, but lateral chromatic aberration is somewhat remained. This lateral chromatic aberration written in the form relative to the wavelength is shown in FIGS. 4 and 5. According to the graphs, since a large amount of lateral chromatic aberration is produced in a short wavelength side, if this portion of aberr...

example 1

FIG. 1 is a sectional view showing the lens arrangement of an optical system according to Example 1 of a first embodiment of the present invention in a wide-angle end state W and a telephoto end state T.

The optical system with a wavelength selecting device according to Example 1 is composed of, in order from an object side along the optical axis, an objective optical system OB, a no-power optical group PL, and an imaging device I.

The objective optical system OB is composed, in order from the object along the optical axis, a first lens group G1, a second lens group G2 including an aperture stop S, and a third lens group G3.

The first lens group G1 having negative refractive power as a whole is composed of, in order from the object, a negative meniscus lens L11 having a convex surface facing to the object and an aspherical surface facing to an image, a double concave negative lens L12 having a stronger concave surface facing to the image, and a positive meniscus lens L13 having a...

example 2

FIG. 12 is a sectional view showing the lens arrangement of an optical system according to Example 2 of the first embodiment of the present invention in a wide-angle end state W and in a telephoto end state T.

The optical system with a wavelength selecting device according to Example 2 is composed of, in order from an object side along the optical axis, an objective optical system OB, a no-power optical group PL, and an imaging device I.

The objective optical system OB is composed, in order from the object along the optical axis, a first lens group G1, a second lens group G2 including an aperture stop S, and a third lens group G3. The objective optical system OB according to Example 2 is the same as that of Example 1, so that a duplicated explanation is abbreviated.

The no-power optical group PL arranged to the image side of the objective optical system OB is composed of, in order from the object, a low-pass filter LPF having a plane-parallel shape with no refractive power, and a...

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Abstract

The object is to provide an optical system with a wavelength selecting device. According to one aspect of the present invention, an optical system with a wavelength selecting device includes, in order from an object along an optical axis, an objective optical system composed of optical elements having refractive power and an aperture stop, a no-power optical group composed of optical elements having no refractive power, and an imaging device. The no-power optical group includes the wavelength selecting device for making short wavelength light be selectively substantially non-transparent. The wavelength selecting device preferably satisfies the predetermined conditional expressions.

Description

INCORPORATION BY REFERENCE The disclosures of the following priority applications are herein incorporated by reference: Japanese Patent Application, No. 2001-378795 filed Dec. 12, 2001, Japanese Patent Application No. 2001-380637 filed Dec. 13, 2001, and Japanese Patent Application No. 2002-179148 filed Jun. 19, 2002. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system with a wavelength selecting device having high optical performance over the entire image field suitable for video cameras and electronic still cameras equipped with a solid state imaging device. 2. Related Background Art An imaging device such as a solid state imaging device, which is different from a conventional silver-halide film, has high sensitivity not only visible light but also infrared light having a longer wavelength than visible light. Accordingly, in order flare caused by chromatic aberration of long wavelength light, it is necessary to cut off l...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G02B5/10G02B5/20G02B5/22G02B5/28G02B13/14G02B15/14G02B15/173G02B15/177G02B21/02G02B27/00G03B13/36
CPCG02B5/208G02B5/22G02B5/28G02B5/281G02B5/283G02B27/0018G02B13/146G02B15/14G02B15/173G02B15/177G02B13/14G02B15/145129G02B15/143507
Inventor OHSHITA, KOUICHIMURATANI, MAMI
Owner NIKON CORP
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