Projection Lens with Segmented Groups for Compact HD Imaging
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Solution Overview
Problem
Existing projection lenses have limited magnification ratios and significant magnification chromatic aberration, making them unsuitable for high-definition image display and resulting in large size and poor performance.
Innovation Solution
A projection lens configuration with specific refractive power groups and movement patterns, including a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, along with an aperture stop placement, to achieve high magnification ratios and reduced aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnification ratio is increased to achieve high-definition image projection, then the image quality is improved, but the lens size increases and magnification chromatic aberration becomes more prominent
Solution Approach 1:
The projection lens is divided into six distinct lens groups (Gr1-Gr6) with alternating positive and negative refractive powers. Each group is optimized for specific functions: Gr1 and Gr2 for wide-angle coverage and initial magnification, Gr3 and Gr4 for chromatic aberration correction through negative refractive power, and Gr5 and Gr6 for final image formation and magnification control. This segmentation allows high magnification ratio (0.688) to be achieved while maintaining compact overall lens size and controlling magnification chromatic aberration below 10μm.
2Measurement precision
If the magnification ratio is increased to achieve high-definition image projection, then the image quality is improved, but the magnification chromatic aberration increases
Solution Approach 1:
Lens groups Gr3 and Gr4 are specifically designed with negative refractive power to provide localized chromatic aberration correction. The conditional expression -0.030 < (f3 + f4)/f < -0.005 ensures that the combined negative refractive power of these groups adequately counteracts the positive chromatic aberration generated by the positive refractive power groups (Gr1, Gr2, Gr5, Gr6). This local quality approach allows high magnification ratio (0.688) to be achieved while maintaining magnification chromatic aberration below 10μm, significantly improving image quality for high-definition projection.
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 enables high-definition image projection with improved aberration performance and size reduction, achieving high performance and compactness in projectors.
Implementation Method 1
a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, a fourth lens group having negative refractive power, a fifth lens group having positive refractive power, and a sixth lens group having positive refractive power
Data Source
AI summary
A projection lens includes a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, a fourth lens group having negative refractive power, a fifth lens group having positive refractive power, and a sixth lens group having positive refractive power, in sequence from an enlargement conjugate side, the projection lens performing magnification by changing the spacing between the lens groups, wherein at the time of magnification from the telephoto end to the wide-angle end, the second, third, fourth, and fifth lens groups are moved, and an aperture stop is arranged between the surface of the third lens group closest to a reduction conjugate side and the surface of the fifth lens group closest to the enlargement conjugate side.