Fresnel Projection Screen Micro-Ridges for Ambient Light Contrast
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Solution Overview
Problem
Conventional projection screens face challenges in reducing ambient light reflections, leading to poor contrast and high costs due to complex and expensive manufacturing processes, with existing solutions only partially addressing the issue of ambient interferences.
Innovation Solution
A front-end projection screen with micro-ridges forming a Fresnel surface, where the bottom surfaces reflect incident light beams as horizontal parallel beams and the top surfaces are coated with a dark material to minimize ambient reflections, eliminating interferences from various directions while maintaining image brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional front projection screens are used, then the manufacturing process is simple and cost is low, but the contrast is poor due to ambient light reflections
Solution Approach 1:
The screen surface is segmented into multiple reflective layers with different orientations. Each layer reflects ambient light from specific directions away from the viewer, while collectively maintaining the projected image. This segmentation allows the screen to address ambient light interference from multiple angles without requiring complex single-layer structures.
Solution Approach 2:
The projection screen employs a composite structure combining multiple reflective layers with different optical properties. These layers work together to differentiate between projected light and ambient light, achieving high contrast without requiring expensive specialized materials or complex manufacturing processes.
2Manufacturing precision
If multiple layered screens or specially processed surfaces are used to improve contrast, then ambient light interference is reduced, but the manufacturing becomes complicated and costly
Solution Approach 1:
Rather than using a single complex multi-layer structure, the invention segments the reflective function into multiple simpler layers with different orientations. Each layer handles specific ambient light directions, simplifying the manufacturing of individual layers while achieving complex overall performance through their combination.
Solution Approach 2:
The multiple reflective layers serve universal functions of reflecting both projected light and ambient light, but with different directional characteristics. This multi-functionality allows each layer to be manufactured using similar processes while collectively providing superior contrast performance.
3Object-affected harmful factors
If polarizing filters are used to reduce ambient light, then some ambient interference is reduced, but the brightness of displayed images is reduced by half
Solution Approach 1:
Instead of uniformly filtering all light through a polarizing filter, the invention applies different reflective properties to different regions and layers of the screen. Each layer is optimized to reflect specific types of light (projected vs. ambient) from specific directions, preserving brightness while reducing interference locally.
Solution Approach 2:
The invention converts the harmful effect of ambient light reflections into a beneficial selective reflection process. By using multiple layers with different orientations, the screen reflects ambient light away from viewers while simultaneously reflecting projected light toward viewers, turning the presence of ambient light into an opportunity for enhanced contrast without sacrificing brightness.
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 effectively reduces ambient light interferences, enhancing image contrast and quality without the need for complex or costly manufacturing processes, providing a cost-effective and comfortable viewing experience.
Implementation Method 1
micro-ridges formed with a reflection portion located on the bottom facing the image light source... the reflection portions of the ridges form a combined Fresnel surface to reflect all the incident beam from a focal point of the Fresnel surface to horizontal parallel light beams directing to the viewer
Implementation Method 2
The non-reflection top ridge surfaces are coated with a non-reflecting dark material such that the ambient light mostly incident from the lights typically disposed on the ceiling can be eliminated
Data Source
AI summary
An image display system includes a reflecting screen that has a reflecting surface. The reflecting surface includes micro-ridges having a plurality of reflecting ridge-surfaces wherein the reflecting ridge-surfaces constituting a Fresnel mirror whereby the reflecting ridge-surfaces reflecting parallel reflecting light beams for all incident light beams projected from a light source located at a focal point of the Fresnel mirror. The micro-ridges further include a plurality of darkened ridge-surfaces with reduced reflectance for reducing ambient reflections. The micro-ridges further constitute a continuous concentric ridge having the reflecting ridge-surfaces facing a bottom direction toward the focal point of the Fresnel mirror for disposing a light source near a bottom location of the projecting screen. The continuous concentric ridge further has reduced reflectance ridge-surfaces facing a top direction away from the focal point of the Fresnel mirror.