Projector Illuminating Optical System Arc Image Reduction
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Solution Overview
Problem
The existing illuminating optical systems for liquid crystal projectors, particularly those with L-, U-, and S-shaped arrangements, suffer from reduced polarization conversion efficiency due to the large size of arc images formed on the second integrator, which results in a significant portion of light falling out of the effective aperture of the polarization converting element, leading to increased costs and reduced illumination efficiency.
Innovation Solution
The optical system is redesigned with a shorter distance between the field lens and the condenser lens, allowing the field lens to superimpose luminous fluxes from the first integrator directly onto the display panels, and the condenser lens is positioned closer to the color separating unit, reducing the synthesizing focal distance and the size of arc images on the second integrator, thus improving polarization conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distance between the field lens and the condenser lens is reduced, then the synthesizing focal distance is shortened and arc image size is reduced, but the optical path length is reduced which may affect illumination coverage
Solution Approach 1:
The patent applies parameter changes by optimizing the distance between the field lens and condenser lens to a specific range (50-150mm) and adjusting the focal lengths of these lenses. This changes the synthesizing focal distance parameter to reduce arc image size while maintaining adequate optical path length for proper illumination coverage.
2Reliability
If the arc image size on the second integrator is reduced, then polarization conversion efficiency is improved, but the illumination intensity may be reduced due to tighter focusing
Solution Approach 1:
The patent changes parameters by optimizing the focal lengths of the field lens and condenser lens, and by setting their distance apart within a specific range. This achieves a balance where arc images are sufficiently small for high polarization conversion efficiency while maintaining adequate illumination intensity through proper optical design.
Solution Approach 2:
The patent introduces adjustability in the optical system by allowing the distance between the field lens and condenser lens to be optimized within a range (50-150mm). This dynamic parameter adjustment enables optimization of both arc image size and illumination intensity depending on specific application requirements.
3Volume of moving object
If the synthesizing focal distance is shortened, then the optical system size is reduced, but the depth of field is reduced which may affect focus quality
Solution Approach 1:
The patent applies parameter changes by optimizing the focal lengths of the field lens and condenser lens and their separation distance. This achieves a compact optical system with shortened synthesizing focal distance while maintaining adequate depth of field through careful parameter selection within the specified ranges.
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 enhances polarization conversion efficiency and illumination efficiency by ensuring that the arc images formed on the second integrator are within the effective aperture of the polarization converting element, reducing light loss and maintaining focus on the liquid crystal display panel.
Implementation Method 1
a field lens and a condenser lens are arranged between the polarization converting element and the color separating unit, the field lens superimposes, on the plurality of display panels, the luminous fluxes that have passed through the respective lens cells of the first integrator
Implementation Method 2
the condenser lens is positioned closer to the color separating unit, reducing the synthesizing focal distance and the size of arc images on the second integrator
Implementation Method 3
a polarization converting element that uniformizes polarizing directions of the luminous fluxes that have passed through the respective lens cells of the second integrator
Implementation Method 4
a color separating unit that separates each of the luminous fluxes from the polarization converting element into a plurality of color lights including different wavelengths
Data Source
AI summary
An illuminating optical system that includes a first integrator that includes a plurality of lens, a second integrator that includes a plurality of lens cells on which the respective partial luminous fluxes are incident, a polarization converting element that uniformizes polarizing directions of the luminous fluxes that have passed through the respective lens cells of the second integrator, and color separating unit that separates each of the luminous flux from the polarization converting element into a plurality of color lights of different wavelengths. A field lens and a condenser lens are arranged between the polarization converting element and the separating unit to superimpose the luminous fluxes that have passed through the respective lens cells of the first integrator, on the plurality of display panels. The condenser lens is located closer to the color separating unit.