Projection Screen with Inclined Reflective Patterns for Brightness Uniformity
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Solution Overview
Problem
Short-throw projectors cause brightness imbalances and contrast deterioration due to large incident angles and external light reflection in projection systems, especially in bright room environments.
Innovation Solution
A projection screen with a reflective layer featuring inclined image reflective surfaces and external light absorption layers, arranged in patterns to guide image light and absorb external light, reducing brightness imbalances and contrast deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a short-throw projector is used to reduce projection distance, then the projection distance is shortened, but brightness imbalance occurs on the screen due to large incident angles
Solution Approach 1:
The screen surface is divided into multiple local regions with different reflective properties. The reflective layer includes multiple reflective patterns (e.g., microlenses, mirrors, or prisms) arranged in specific patterns, where each local region redirects light at different angles to compensate for the incident angle variation across the screen, achieving uniform brightness distribution
Solution Approach 2:
The solution introduces a new dimension of light control by adding a reflective layer with three-dimensional microstructures. These microstructures manipulate light in the vertical dimension (incident angle compensation) while maintaining the two-dimensional image display function, effectively decoupling the projection distance constraint from the brightness uniformity requirement
2Illumination intensity
If the screen reflects external light toward the viewer, then the screen maintains high reflectivity for image light, but contrast deteriorates due to reflected external light
Solution Approach 1:
The screen structure is segmented into functional zones: image light reflective regions and external light absorbing regions. The reflective layer contains multiple reflective patterns arranged in specific patterns, while absorption layers are positioned in complementary regions to selectively target external light paths without interfering with image light reflection
Solution Approach 2:
The screen converts the harmful effect of external light reflection into a beneficial effect by using the same reflective patterns to guide external light toward absorption layers. The reflective patterns that would normally reflect external light toward viewers are instead configured to redirect external light into absorption regions, transforming the harmful reflection into useful light trapping
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 screen effectively addresses brightness imbalances and contrast issues by directing image light uniformly and absorbing external light, enhancing image quality in short-throw projector systems.
Implementation Method 1
a reflective layer having plural reflective patterns which are spaced apart from one another and each of which includes an image reflective surface having an inclination angle against a horizontal direction so as to guide an image light toward a front of the screen
Implementation Method 2
plural external light absorption layers absorbing external lights incident to the screen
Data Source
AI summary
A projection screen is provided, which includes a reflective layer having plural reflective patterns which are spaced apart from one another and each of which includes an image reflective surface having an inclination angle against a horizontal direction so as to guide an image light toward a front of the screen, and plural external light absorption layers absorbing external lights incident to the screen.