Two-Element Aspheric Projection Lens for Compact Optical Systems
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Solution Overview
Problem
There is a need for projection lens systems in electronic devices to be miniaturized while maintaining good projection quality, as devices are equipped with increasing functionalities and a trend towards compact size.
Innovation Solution
A projection lens system comprising two lens elements with specific refractive indices, central thicknesses, and axial distances, along with aspheric surfaces and optional diffractive optical elements, to achieve a balance between size and projection quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of lens elements is increased to improve projection quality, then projection quality is improved, but the system size increases
Solution Approach 1:
The patent divides the projection lens system into exactly two functional lens elements: a first lens element with positive refractive power and a second lens element with negative refractive power. This segmentation allows the system to achieve good projection quality with minimal components, resolving the contradiction between quality and size by using only the necessary number of elements.
Solution Approach 2:
The patent applies parameter changes by specifying that at least one surface of at least one lens element must be aspheric, and by defining specific refractive power relationships (first lens element positive, second lens element negative). These parameter optimizations enable two elements to achieve projection quality that would traditionally require more elements, thus reducing system size while maintaining quality.
2Reliability
If aspheric surfaces are used to improve projection quality, then projection quality is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by requiring aspheric surfaces only at specific locations (at least one of the magnification-side surface or reduction-side surface of at least one lens element) rather than all surfaces. This localized application of aspheric design maintains projection quality while reducing manufacturing complexity compared to making all surfaces aspheric.
3Volume of moving object
If the axial distance between lens elements is reduced to miniaturize the system, then system size is reduced, but projection quality deteriorates
Solution Approach 1:
The patent uses parameter changes by defining specific refractive power relationships between the two lens elements (first element positive, second element negative) and specifying aspheric surface requirements. These parameter optimizations enable the lens elements to be positioned closer together while maintaining projection quality, effectively resolving the contradiction between miniaturization and quality.
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 system achieves reduced size and improved projection quality by optimizing lens elements' refractive indices, thicknesses, and surface shapes, while allowing for flexible design and manufacturing options using glass or plastic materials.
Implementation Method 1
The first lens element has positive refractive power, and at least one of the magnification-side surface and the reduction-side surface of at least one of the two lens elements is aspheric
Data Source
AI summary
A projection lens system includes two lens elements being, in order from a magnification side to a reduction side along an optical path, a first lens element, and a second lens element. Each of the two lens elements has a magnification-side surface facing the magnification side and a reduction-side surface facing the reduction side. At least one of the magnification-side surface and the reduction-side surface of at least one of the two lens elements is aspheric.