Rear-projection screen collimation lens layer luminance uniformity
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Solution Overview
Problem
Rear-projection screens with Fresnel micro-lens structures suffer from non-uniform luminance due to energy loss as light beams are reflected, leading to higher energy loss at the edges compared to the center, especially with shorter focus distances, resulting in poor luminance uniformity across the screen.
Innovation Solution
A rear-projection display system incorporating a collimation lens layer with a target region and a Fresnel lens region, where the target region is outside the Fresnel lens region, and N light path turning systems adjust the light paths to ensure light is incident at a reduced angle, minimizing reflection loss and enhancing luminance uniformity by distributing light uniformly across the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a Fresnel micro-lens structure is used in the rear-projection screen, then light direction control is improved, but luminance uniformity deteriorates due to energy loss and reflection at the edges
Solution Approach 1:
The rear-projection screen is divided into two distinct regions: a Fresnel lens region for central light control and a target region without Fresnel lenses for edge light distribution. This segmentation allows each region to be optimized for its specific function, reducing overall energy loss and improving luminance uniformity across the entire screen.
Solution Approach 2:
Different optical properties are applied to different parts of the screen. The Fresnel lens region provides focused light control where needed, while the target region uses a flat or differently structured surface to distribute light more evenly at the edges, creating local optimization for luminance uniformity.
2Length of moving object
If the focus distance of the projector is shortened, then projection distance is reduced, but luminance uniformity deteriorates due to increased energy loss
Solution Approach 1:
By segmenting the screen into Fresnel lens region and target region, the system can accommodate shorter projection distances while maintaining luminance uniformity. The target region specifically addresses edge light distribution issues that become more pronounced at shorter focus distances.
3Illumination intensity
If light beams are reflected multiple times in the Fresnel lens structure, then light direction is controlled, but energy loss increases
Solution Approach 1:
The target region extracts the function of edge light distribution from the Fresnel lens structure, allowing light to reach the edges with minimal reflection and energy loss while the Fresnel lens region maintains its light direction control capabilities for the central area.
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 system reduces energy loss to less than 5%, significantly improving luminance uniformity across the rear-projection screen while maintaining accurate light propagation, compared to the 10-20% loss in traditional systems.
Implementation Method 1
a collimation lens layer including a target region and a Fresnel lens region, wherein the target region is arranged outside the Fresnel lens region, and emergent light exiting the target region is parallel to the normal of the collimation lens layer
Implementation Method 2
a collimation lens layer including a target region and a Fresnel lens region, wherein the Fresnel lens region receives first projected light directly from a projector
Implementation Method 3
the N light path turning systems are configured to receive the second projected light emitted by the projector, and to have the second projected light incident onto the target region at a first angle less than the emitting angle of the second projected light
Data Source
AI summary
A rear-projection display system and a rear-projection screen are provided. The system includes a projector, N light path turning systems, and a rear-projection screen, wherein the rear-projection screen includes a collimation lens layer including a target region and a Fresnel lens region; the projector is configured to emit first projected light which is incident directly onto the Fresnel lens region, and emit second projected light which is incident onto the N light path turning system; and the N light path turning systems are configured to receive the second projected light from the projector, and to have the second projected light incident onto the target region at a first angle less than the emitting angle of the second projected light.