Zoom Lens with Reflection Element for Thinning Profile
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Solution Overview
Problem
Conventional zoom lenses with a wide angle of view and reflection optical elements have a large object side lens length, making them thick and difficult to downsize, as the lens configuration is inefficient in folding the optical path effectively.
Innovation Solution
A zoom lens configuration with a first lens group having negative refractive power and a reflection optical element, where the position of the first lens group is fixed along the optical axis from the wide-angle to telephoto end state, and the ratio of the focal length of the front group to the optical path length of the reflection element is optimized to achieve a thinner profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflection optical element is disposed in the zoom lens to achieve a wide angle of view, then the angle of view is improved, but the object side lens length becomes large making the lens thick
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio of the focal length of the front group to the optical path length of the reflection optical element within a specific range (0.89 < -f1p/Dp < 1.50). This parameter optimization enables effective control of the object side lens length while maintaining a wide angle of view, resolving the contradiction between achieving wide angle and keeping the lens thin.
2Illumination intensity
If the zoom lens is widened to achieve a wide angle of view, then the angle of view is improved, but the lens size increases making downsizing difficult
Solution Approach 1:
The patent uses parameter changes by controlling the ratio of focal length to optical path length within a specific range, which enables the lens to achieve a wide angle of view without increasing the overall lens volume, thus resolving the contradiction between wide angle and downsizing.
Solution Approach 2:
The patent employs a reflection optical element to fold the optical path, effectively utilizing the lateral dimension to extend the optical path length without increasing the axial length of the lens. This dimensional approach allows achieving wide angle of view while maintaining a compact lens size.
3Length of moving object
If the object side lens length is shortened to thin the lens profile, then the lens thickness is improved, but the lens configuration becomes inefficient
Solution Approach 1:
The patent resolves this contradiction by optimizing the parameter ratio of focal length to optical path length within a specific range. This optimization ensures that the lens configuration remains efficient while achieving the desired thin profile, as the parameter control maintains proper optical performance despite the shortened length.
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
This configuration allows for a downsized zoom lens with a wide angle of view by shortening the object side lens length from the reflection optical element, effectively correcting curvature of field and other aberrations while enabling thinning and downsizing of the lens.
Implementation Method 1
a reflection optical element that folds an optical path
Data Source
AI summary
With comprising, in order from an object side: a first lens group G1 having negative refractive power; a second lens group G2; and a third lens group G3, the first lens group G1 includes, in order from the object side, a front group having negative refractive power, and a reflection optical element P that folds an optical path, a position of the first lens group G1 being fixed along the optical axis upon zooming from a wide-angle end state W to a telephoto end state T, and satisfying a given conditional expression, thereby providing a downsized zoom lens having a reflection optical element and a wide angle of view with thinning its profile by means of shortening a distance along an optical axis between the most object side lens surface and an object side optical surface of the reflection optical element.