Compact Relay Lens Extender for Telescope Magnification
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Solution Overview
Problem
Telescopes with fixed focal length or zoom eyepieces lack the ability to provide additional magnification for special applications without increasing weight and cost, as existing solutions for focal length extenders are either cumbersome or not available for these requirements.
Innovation Solution
A focal length extender with an intermediate optic of negative refractive power, mechanically connected to the eyepiece, which includes a relay lens system that adjusts the magnification factor and imaging length within a compact and lightweight design, using connecting elements that protrude minimally from the housing, allowing for easy attachment and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional magnification is achieved by adding more eyepieces or optical components, then the magnification capability is improved, but the weight and device complexity increase
Solution Approach 1:
The extender housing contains the relay lens system within its structure, with the relay lens mounted in a holder that is integrated into the housing. The connecting elements are positioned within the housing boundaries, creating a nested arrangement where all components are contained within the extender's external dimensions, minimizing overall size and weight while providing additional magnification capability.
2Volume of moving object
If the extender housing thickness is reduced for compactness, then the device size is improved, but the mechanical limit for fasteners and optical adjustment is worsened
Solution Approach 1:
The connecting elements protrude axially from the stop planes along the optical axis direction, utilizing the length dimension rather than requiring increased thickness in the radial or lateral dimensions. This allows the housing to maintain a compact thickness of 30 mm while still providing sufficient mechanical engagement length for robust bayonet-style connecting elements, effectively distributing the dimensional requirements across different spatial axes.
3Device complexity
If a single relay lens is used instead of multiple lenses, then the device complexity and manufacturing cost are improved, but the focal length extension capability is limited
Solution Approach 1:
The single relay lens has its focal length and optical parameters specifically optimized to provide approximately 1.8x magnification when positioned at a specific distance from the eyepiece's exit pupil. By carefully selecting the lens focal length and positioning it precisely within the housing, the system achieves the desired focal length extension with a single lens, avoiding the complexity of multiple lenses while maintaining effective magnification capability.
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 provides an additional magnification factor of approximately 1.8 times with minimal weight and cost, maintaining a compact design and reducing the subjective field of view impact, while allowing for easy adjustment and manufacturing tolerances.
Implementation Method 1
A relay lens 10 with negative refractive power is inserted into the holder 9
Data Source
AI summary
A focal length extender (1) for telescopes with interchangeable eyepieces, comprising a cylindrical housing (2) which has a first (4) and a second (5) stop plane (4, 5) perpendicular to the cylinder axis (6) in the direction of light (3), with associated connecting elements (7, 8) to the telescope and to the interchangeable eyepiece, is characterized in that a) the housing (2) has a holder (9) arranged at a distance in front of the first stop plane (4) with a relay lens (10) arranged perpendicular to the cylinder axis (6), wherein b) the distance and focal length of the relay lens (10) are selected such that an object plane O defined relative to the first stop plane (4) is enlarged by a factor β' and shifted into an image plane O' with the same relative position to the second stop plane (5), and wherein c) the distance B between the first and the second stop plane (4, 5) is equal to the amount of the focal length shift OO' is.