Wide-Angle Lens Vibration Reduction Aberration Control
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Solution Overview
Problem
Conventional wide-angle optical systems with vibration reduction mechanisms fail to adequately correct aberrations and are prone to ghost images and flare due to insufficient correction of aberrations and reflection light from optical surfaces.
Innovation Solution
An optical system comprising a first lens group, a second lens group with negative refractive power disposed movably perpendicular to the optical axis, and a third lens group with positive refractive power, where the second lens group is positioned between the first and third lens groups, and an aperture stop is placed on the image side of the second lens group, optimizing the focal length and refractive power distribution to enhance aberration correction and reduce ghost images and flare.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a vibration reduction mechanism is applied to a conventional wide-angle optical system, then vibration reduction function is added, but correction of aberration upon vibration reduction is not sufficient
Solution Approach 1:
The optical system is divided into multiple lens groups (first lens group with positive refractive power, second lens group with negative refractive power, third lens group with positive refractive power). The second lens group is specifically designated as the vibration reduction lens group that can move independently perpendicular to the optical axis, allowing aberration correction to be handled separately from the vibration reduction function.
Solution Approach 2:
The second lens group with negative refractive power is positioned between the first and third lens groups and is configured to move perpendicular to the optical axis for vibration reduction. This localized movement capability enables the system to correct aberrations specifically in the region where the vibration reduction lens group operates, without affecting the overall optical performance.
2Volume of moving object
If conventional wide-angle optical system design is used, then compact structure is achieved, but reflection light producing ghost images and flare is liable to be generated from optical surfaces
Solution Approach 1:
The patent utilizes the retrofocus lens configuration with a negative second lens group to intentionally create a larger back focal length, which provides space for positioning the vibration reduction lens group. This configuration, while increasing system length slightly, enables effective placement of anti-reflection coatings and vibration reduction components that reduce ghost images and flare.
Solution Approach 2:
The optical system employs specific refractive power distributions (positive-negative-positive configuration) and satisfies conditional expressions for focal lengths and distances. These parameter optimizations minimize reflection light by controlling the angles of incidence on optical surfaces, thereby reducing ghost images and flare while maintaining a relatively compact form factor.
3Manufacturing precision
If multilayer coating technology is applied to suppress ghost images and flare, then optical performance is improved, but device complexity increases
Solution Approach 1:
The patent extracts the vibration reduction function into a separate movable second lens group, which can be independently optimized. This separation allows the application of specialized anti-reflection coatings and vibration reduction treatments on specific surfaces without requiring complex multilayer coatings on the entire optical system, thereby reducing overall device complexity while maintaining high optical performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves excellent vibration reduction performance, effective correction of various aberrations, and suppression of ghost images and flare, thereby improving the overall optical performance of the system.
Implementation Method 1
a second lens group having negative refractive power, disposed to an image side of the first lens group movably in a direction including a component perpendicular to an optical axis
Data Source
AI summary
An optical system SL installed in a single-lens reflex camera includes, in order from an object side, a first lens group G1, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power. The second lens group G2 is disposed movably in a direction including a component perpendicular to an optical axis, and a given conditional expression is satisfied, thereby providing an optical system having excellent optical performance with excellent vibration reduction performance, an optical apparatus equipped with the optical system, and a method for manufacturing the optical system.