Converter Device Reimaging Optical System for Wide-Angle Lenses
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Solution Overview
Problem
Conventional converter devices are unsuitable for interchangeable lenses with wide field angles and those used in mirrorless cameras, as they struggle to effectively extend focal lengths due to short back focus and space constraints.
Innovation Solution
A converter device with a reimaging optical system that reimages the primary image formed by the interchangeable lens, allowing for high imaging magnification and expansion of imaging functions without vignetting, even when attached to lenses with short back focus, by optimizing the imaging magnification and refractive power distribution within the reimaging optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional teleconverter is attached to an interchangeable lens with short back focus, then the attachment position moves toward the image side, but the lens component having negative refractive power is arranged at a position where the height of an axial ray is low, making it difficult to sufficiently extend the focal length
Solution Approach 1:
The patent employs a movable lens component (negative refractive power lens) that can shift position along the optical axis. This dynamic adjustment allows the lens to be positioned at the optimal location where axial ray height is maximized, even when the converter is attached to lenses with short back focus. The movable mechanism enables the system to adapt to different attachment positions and maintain effective focal length extension capability.
Solution Approach 2:
The patent changes the positional parameter of the negative refractive power lens component along the optical axis. By adjusting this parameter, the lens can be placed at different heights relative to the axial rays, optimizing the focal length extension effect. This parameter adjustment compensates for the limited space in short back focus lens configurations.
2Ease of operation
If the lens component having negative refractive power is arranged at a position where the height of an axial ray is low, then the attachment is feasible, but the focal length of the interchangeable lens cannot be sufficiently extended
Solution Approach 1:
The negative refractive power lens component is designed to be movable rather than fixed. This allows it to dynamically adjust its position to maximize axial ray height and focal length extension effectiveness, while still maintaining attachment feasibility to lenses with various back focus lengths.
Solution Approach 2:
The converter device is segmented into movable and fixed components. The negative refractive power lens is separated as a movable element that can be independently positioned, allowing optimization of its location for focal length extension without affecting the overall attachment structure.
3Adaptability or versatility
If a converter device is attached to an interchangeable lens with wide field angle, then the back focus is short, but it becomes difficult to extend the focal length due to space constraints
Solution Approach 1:
The movable negative lens component can adjust its position to optimize performance in the limited space of wide field angle lenses with short back focus. This dynamic positioning enables effective focal length extension despite the constrained space, making the converter compatible with various lens types including wide field angle lenses.
Solution Approach 2:
The system adjusts the positional parameters of lens components to adapt to different lens configurations. By changing these parameters, the converter can achieve effective focal length extension in the limited space available in wide field angle lens attachments.
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
Enables effective focal length extension and high optical performance for interchangeable lenses with wide field angles and those used in mirrorless cameras, preventing vignetting and allowing for downsizing of the converter device while maintaining image quality.
Implementation Method 1
a lens component having negative refractive power and a lens component having positive refractive power are arranged in order from the object side. The focal length of the interchangeable lens is extended by making axial light flux be afocal with the lens component having negative refractive power and by converging the light flux with the lens component having positive refractive power.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
In a converter device that is attached between a lens device, which is attachable to and detachable from an image capturing apparatus, and the image capturing apparatus, and that has a reimaging optical system configured to reimage a primary image formed by the lens device on an image plane as a secondary image, the imaging magnification of the reimaging optical system and imaging positions of a primary image and a secondary image are appropriately set.