Projection Screen Microstructure Layer Ambient Light Contrast
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Solution Overview
Problem
Existing projection screens suffer from low contrast due to the reflection of ambient light, which affects the image quality, as they often reflect both projection and ambient light, leading to a lower contrast ratio than the projector itself.
Innovation Solution
A projection screen with a microstructure layer and a light-absorbing layer, where the microstructure units include a reflective surface and a lens surface arranged to focus projection light, reducing the duty cycle of the reflective surface and enhancing the absorption or reflection of ambient light, thereby improving contrast and gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the screen reflects both projection light and ambient light, then the brightness of the displayed image is maintained, but the contrast of the displayed image deteriorates
Solution Approach 1:
The screen structure is divided into different regions with distinct functions: the first light-receiving surface is designed to reflect projection light while the second light-receiving surface is designed to absorb ambient light. This local differentiation allows the screen to maintain brightness through selective reflection while improving contrast by preventing ambient light from reaching the viewing area
Solution Approach 2:
The screen is segmented into multiple functional layers including a light-absorbing layer, a first light-receiving surface, a second light-receiving surface, and a light-reflecting surface. Each segment performs a specific optical function, allowing the system to selectively manage different light sources (projection light vs. ambient light) to achieve both high brightness and high contrast
2Power
If the reflective surface area is increased to improve gain, then the projection light reflection is enhanced, but the ambient light reflection also increases causing contrast deterioration
Solution Approach 1:
Different regions of the screen have different reflectivity characteristics: the first light-receiving surface has high reflectivity for projection light to achieve high gain, while the second light-receiving surface has low reflectivity (high absorption) for ambient light to maintain contrast. This localized quality differentiation resolves the contradiction between gain and contrast
3Manufacturing precision
If a light-absorbing layer is added to reduce ambient light reflection, then the contrast is improved, but the projection light reflection may be reduced
Solution Approach 1:
The light-absorbing layer is positioned and configured to selectively absorb only the ambient light that would otherwise reach the second light-receiving surface, while the first light-receiving surface and light-reflecting surface maintain their ability to reflect projection light. This segmented approach allows simultaneous achievement of high contrast and high gain
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 the overall reflectivity of the screen while maintaining high projection light reflection, resulting in improved anti-ambient light performance and higher contrast, enhancing the image quality by minimizing the impact of ambient light.
Implementation Method 1
The microstructure layer includes a plurality of microstructure units, each of the plurality of microstructure units includes a reflective surface and a lens surface opposite to the reflective surface, and the reflective surface is provided at a position matching a focus of the lens surface
Implementation Method 2
both the lens surface and the reflective surface reflect the projection light
Implementation Method 3
a light absorbing layer that is arranged on a far side of the microstructure layer from a projection light incident side
Data Source
Figure 1~1c
Figure 2a~2b
Figure 3~4
AI summary
A projection screen and a projection system using the projection screen. The projection screen comprises a microstructure layer (20) and a light absorbing layer (10) sequentially stacked from the side where a projected light is introduced. The microstructure layer (20) comprises multiple microstructure units. Each microstructure unit comprises one reflective surface (21) and one lens surface (22) opposite the reflective surface (21); moreover, the reflective surface (21) is provided at a position matching the focus of the lens surface (22). The projection screen and the projection system can resist ambient light and have a high gain and a high contrast.