Microfaceted Projection Screen Light Direction
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Solution Overview
Problem
Short throw projectors experience significant light reflection towards the ceiling due to the design of existing projection screens, leading to inefficient light distribution and viewer alignment.
Innovation Solution
A projection screen with micro-facets and micro grooves that reflect light towards the viewer without the need for lenticular lenses, where the orientation and shape of each facet are tailored to accommodate varying light angles from the projector, ensuring even brightness and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional projection screen is used with a short throw projector, then the projector can be positioned close to the screen, but most of the projected light is reflected toward the ceiling instead of toward the viewer
Solution Approach 1:
The projection screen surface is segmented into multiple micro-facets within each pixel area, where each micro-facet is oriented at different angles to reflect light toward the viewer. This segmentation allows the screen to redirect light that would otherwise reflect toward the ceiling, converting energy loss into useful illumination for the viewer.
Solution Approach 2:
Each pixel area on the projection screen has locally varied micro-facet orientations tailored to the specific light angle from the short throw projector. The micro-facets in different regions of the screen have different orientations to accommodate the changing angle of incident light across the projection surface, ensuring optimal light reflection toward the viewer at each location.
2Illumination intensity
If micro-facets with varying orientations are used to reflect light toward the viewer, then light distribution is improved, but the manufacturing complexity increases
Solution Approach 1:
The micro-facet orientation parameters (angles in vertical and horizontal directions) are systematically varied across different pixel areas to match the changing light angles from the projector. This parameter variation achieves even brightness distribution and proper light reflection, while the systematic approach allows for controlled manufacturing processes.
3Illumination intensity
If lenticular lenses are used to direct light toward the viewer, then light reflection is improved, but the device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the lenticular lens component from the projection system by replacing it with micro-faceted screen surfaces that perform the light-directioning function. This removal of the lens simplifies the overall device structure, reduces complexity, and eliminates the need for precise alignment between the lens and projector while achieving the same light control objective.
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 micro-faceted projection screen effectively directs light towards the viewer, reducing ceiling reflection and improving image clarity and alignment, eliminating the need for precise projector-screen alignment.
Implementation Method 1
micro grooves are on the projection screen reflect the light toward the viewer
Data Source
AI summary
To avoid requiring precise alignment between a projector and a projection screen, plural micro etched faceted grooves are provided for each area of the screen onto which a single pixel is to be projected. Each facet may be roughened, or gently curved, and the walls between adjoining facets likewise may be curved.