Projection Optical System Compact Zoom Aberration Control
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Solution Overview
Problem
Conventional projection optical systems face challenges in achieving a shorter overall length and higher variable magnification ratio while effectively suppressing various aberrations.
Innovation Solution
A projection optical system comprising a specific configuration of lens units with defined movements and optical powers, including a first lens unit with negative power, second and third lens units with positive power, and additional units, which satisfy specific focal length and axial interval conditions to enable zooming and focusing without compromising aberration compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional six-unit projection optical system is used with fixed first and sixth lens units during zooming, then the system structure is simplified and ease of manufacture is improved, but the overall length of the lens system becomes longer and the variable magnification ratio is reduced
Solution Approach 1:
The invention makes the first lens unit movable during focusing operation, transforming it from a static fixed component to a dynamic adjustable component. This enables the system to achieve compact overall length and high variable magnification ratio while maintaining ease of manufacture through the standardized six-unit configuration.
2Adaptability or versatility
If lens units are moved during zooming to achieve higher variable magnification ratio, then the magnification capability is improved, but various aberrations such as coma and chromatic aberrations increase
Solution Approach 1:
The invention specifies precise focal length ratios (−0.55 < fW/f1 < −0.30 and 1.80 < f123T/f123W < 2.50) and axial interval relationships for the lens units during zooming. These parameter constraints enable the system to achieve high variable magnification ratio while maintaining effective aberration suppression through optimized optical parameters.
3Ease of operation
If the first lens unit is moved during focusing, then focusing capability is improved, but the device complexity increases
Solution Approach 1:
The invention divides the focusing function into specific lens unit movements (first lens unit for focusing, second and third lens units for zooming) within the six-unit configuration. This segmentation allows independent optimization of focusing and zooming operations, improving ease of operation while managing device complexity through functional separation.
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 a shorter overall length and higher variable magnification ratio while effectively suppressing various aberrations, particularly coma and chromatic aberrations, ensuring high imaging performance across zooming areas.
Implementation Method 1
a projection optical system, in order from a magnification side to a demagnification side, comprising a first lens unit having negative optical power, a second lens unit having positive optical power, a third lens unit having positive optical power
Data Source
AI summary
A projection optical system, in order from a magnification side to a demagnification side, comprising a negative first lens unit, a positive second lens unit, a positive third lens unit, a fourth lens unit, a fifth lens unit, and a sixth lens unit, wherein the second and third lens units move along an optical axis in zooming, the first lens unit moves along the optical axis in focusing, and the conditions: −0.55<fW/f1<−0.30 and 1.9<f123T/f123W<fT/fW (f1: focal length of first lens unit, f123W: composite focal length of first, second and third lens units at wide-angle limit, f123T: composite focal length of first, second and third lens units at telephoto limit, fW: focal length of entire system at wide-angle limit, fT: focal length of entire system at telephoto limit) are satisfied.