Asymmetric Optical Diffuser for Projection Board Glare Reduction
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Solution Overview
Problem
Existing dry erase boards and projection screens fail to provide high brightness, high contrast, and wide viewing angle under bright ambient light conditions, leading to image washout and eye strain due to glare and reflection.
Innovation Solution
A communication article with a dry erasable writing surface and a rear projection member featuring an asymmetric optical diffuser and a substantially specular reflector, which scatters light in different directions and reflects unwanted light, enhancing image visibility and contrast in various lighting conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional dry erase board is used as a projection screen, then the writing surface functionality is maintained, but the glare and reflection cause reduced image contrast and visibility
Solution Approach 1:
The board is divided into two distinct functional layers: a front dry erase surface for writing and a rear projection member with asymmetric optical diffuser and specular reflector for projection. This segmentation allows each layer to optimize its specific function without interfering with the other, eliminating glare while maintaining writing functionality.
Solution Approach 2:
Different optical properties are applied to different regions of the board. The front surface has properties optimized for writing (dry erase capability), while the rear projection member has asymmetric optical characteristics with specific viewing angles optimized for projection. This local differentiation resolves the contradiction between writing and projection functions.
2Ease of operation
If the surface of the dry erase board is made smooth for easy writing, then writing ease is improved, but the optical gain remains low resulting in poor projection performance
Solution Approach 1:
The board is divided into two distinct functional layers: a front dry erase surface for writing and a rear projection member with asymmetric optical diffuser and specular reflector for projection. This segmentation allows each layer to optimize its specific function without interfering with the other, eliminating glare while maintaining writing functionality.
Solution Approach 2:
Different optical properties are applied to different regions of the board. The front surface has properties optimized for writing (dry erase capability), while the rear projection member has asymmetric optical characteristics with specific viewing angles optimized for projection. This local differentiation resolves the contradiction between writing and projection functions.
3Illumination intensity
If ambient light is strong in the room, then overall visibility is improved, but the projected image experiences washout due to reduced contrast
Solution Approach 1:
The projection member employs an asymmetric optical diffuser that scatters light differently in horizontal and vertical directions. This asymmetric scattering pattern concentrates projected light in the desired viewing direction while rejecting ambient light from various angles, maintaining high contrast even in bright rooms.
Solution Approach 2:
The specular reflector is designed to reflect ambient light away from the viewing area, converting the harmful effect of strong ambient light into a beneficial outcome by actively rejecting it. The asymmetric optical structure uses the incident ambient light to demonstrate its rejection capability, turning the challenge of bright environments into a showcase of the projection member's light control performance.
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 clear and easy visibility of written and projected images in meetings and presentations, even in brightly lit environments, by improving image contrast and reducing ambient light interference.
Implementation Method 1
an asymmetric optical diffuser that scatters light in a first direction with a first viewing angle AH, and in a second direction orthogonal to the first direction with a second viewing angle AV
Implementation Method 2
a substantially specular reflector that reflects light that is not scattered by the asymmetric optical diffuser
Implementation Method 3
on the rear side of the specular reflector a light absorbing layer that absorbs light that is not reflected by the substantially specular reflector
Data Source
AI summary
A communication article and system comprising a writing member having a dry erasable front surface and a projection member is disclosed. The projection member includes an asymmetric optical diffuser that scatters light in a first direction with a first viewing angle AH, and in a second direction orthogonal to the first direction with a second viewing angle AV. The ratio AH/AV is at least about 2.