Light Guide Screen Louver Device for Rear Projection Displays
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Solution Overview
Problem
Rear projection display systems face issues with light loss and limited viewing angles due to the design of light guide screens, which affect picture quality and usability in various environments, especially in bright rooms where ambient light is a concern.
Innovation Solution
A louver device is integrated into the light guide screen, comprising a transparent layer with shaped louver members that redirect light entering at one angle to exit at multiple angles, reducing light loss and enhancing the viewing angle, thereby improving picture quality and usability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If light guide screens are used to route light from input to output locations, then the display can be thinner and lighter, but light loss occurs and brightness is reduced
Solution Approach 1:
The patent applies curved or angled louver members instead of flat surfaces to redirect light. The curved geometry of the louver members enables more efficient light redirection towards the viewing audience, reducing light loss while maintaining the thin, lightweight structure of the display.
Solution Approach 2:
The patent changes the geometric parameters of the louver members, including their angles, shapes, and orientations, to optimize light redirection. By adjusting these parameters, the system maximizes light output towards the viewing audience while minimizing light loss in the light guide screen.
2Device complexity
If light guide screens are used to route light, then the display structure is simplified, but viewing angle is limited to the acceptance angle of the light guides
Solution Approach 1:
The curved or angled louver members redirect light over a wider angular range compared to traditional flat light guide screens. This curvature enables the display to maintain simplicity while expanding the viewing angle beyond the acceptance angle limitations of conventional light guides.
Solution Approach 2:
The patent introduces a new dimensional approach by using three-dimensional louver member geometries that can redirect light in multiple directions simultaneously. This adds angular versatility to the otherwise two-dimensional light guide structure, expanding viewing angles without increasing overall system complexity.
3Illumination intensity
If ambient light strikes the viewing surface in bright rooms, then light room contrast is improved, but image clarity and contrast are degraded
Solution Approach 1:
The patent converts the harmful effect of ambient light by using the louver members to redirect light in a controlled manner. The same light redirection mechanism that prevents light loss also works to direct light away from the viewing surface in ways that minimize ambient light interference, effectively turning a potential harm into a benefit for maintaining image quality in bright environments.
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 louver device effectively reduces light loss and expands the viewing angle, providing better contrast and image clarity in diverse environments, including bright rooms, by redirecting light more efficiently towards the viewer.
Implementation Method 1
shaped louver members aligned to receive light entering the first surface at a first angle relative to the first surface and direct the light out the second surface at a plurality of angles relative to the second surface
Implementation Method 2
light guide screens (LGSs)... utilize light guides, such as optical fibers, to route an image from an input location to an output location
Data Source
AI summary
In a particular embodiment, the louver device includes a transparent layer of material having a first surface and, parallel thereto, a second surface. A plurality of shaped louver members are disposed within the transparent layer of material. The shaped louver members are aligned to receive light entering the first surface at a first angle relative to the first surface and direct the light out the second surface at a plurality of angles relative to the second surface.