Compact Zoom Lens Design for Miniaturized Projectors
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Solution Overview
Problem
Current projector units with DMD light valves face challenges in miniaturization while maintaining high image quality and the ability to project enlarged images on large screens, due to the complexity and size constraints of compact zoom lenses.
Innovation Solution
A compact zoom lens design comprising four lens groups with specific refractive powers and movements along the optical axis, satisfying conditional expressions for focal lengths and airspace relationships, to achieve variable power and maintain image quality within limited space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a compact zoom lens is designed to reduce projector thickness, then portability is improved, but image quality on large screens deteriorates
Solution Approach 1:
The zoom lens is divided into four distinct lens groups (first with negative refractive power, second with positive or negative refractive power, third with positive refractive power, and fourth with positive refractive power), each capable of independent movement along the optical axis. This segmentation allows complex optical functions to be distributed across multiple groups, enabling compact design while maintaining image quality through coordinated movement of individual groups during zooming and focusing operations.
2Adaptability or versatility
If lens groups are moved to achieve variable power from wide angle to telephoto, then zoom capability is improved, but device complexity increases
Solution Approach 1:
The zoom lens employs dynamic movement of lens groups along the optical axis to achieve variable power. The first and second lens groups move in opposite directions (first group from magnifying side to contracting side, second group from contracting side to magnifying side) during zooming, while the third lens group moves from contracting side to magnifying side. This dynamic coordination of multiple lens groups enables continuous focal length adjustment while maintaining focus, providing versatile zoom capability through controlled mechanical movement.
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 design enables a thin, portable projector unit capable of projecting high-quality enlarged images, balancing optical system size, aberration correction, and miniaturization requirements.
Implementation Method 1
a first lens group having a negative refractive power as a whole, a second lens group having a positive or negative refractive power as a whole, a third lens group having a positive refractive power as a whole and a fourth lens group having a positive refractive power as a whole
Data Source
AI summary
There is provided a compact zoom lens having a small lens aperture which an image from a light valve such as a DMD is projected on to a screen in an enlarged scale.There is provided a zoom lens comprising, in order from a magnifying side, a first lens group having a negative refractive power as a whole, a second lens group having a positive or negative refractive power as a whole, a third lens group having a positive refractive power as a whole and a fourth lens group having a positive refractive power as a whole, wherein a variable power as a whole lens system thereof is established by configuring such that the fourth lens group is left fixed while a variable power is effected, and the first lens group, the second lens group and the third lens group are made to move on the optical axis.