Light Guide Outcoupling Elements for Dual-View Privacy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display technologies face challenges in providing a wide viewing angle for sharing information while maintaining privacy, often resulting in reduced brightness, complex designs, and limited dual-view modes with residual light issues.
Innovation Solution
An illuminating apparatus with a backlight unit and a plate-shaped light guide featuring outcoupling elements that scatter light minimally, allowing for operation in multiple modes to control angular ranges of luminance, ensuring high black-and-white contrast and minimal residual light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If micro-louver foils are used for visual data protection, then privacy protection is improved, but light loss increases and the structure becomes more complex
Solution Approach 1:
The patent replaces mechanical micro-louver foils with a light guide structure that uses optical principles (total internal reflection and controlled light extraction) to achieve privacy protection without the light loss associated with mechanical filtering systems
Solution Approach 2:
The patent changes the approach from filtering light (foils) to directing light (light guide with controlled extraction surfaces), fundamentally altering how privacy is achieved and eliminating the associated light loss
2Adaptability or versatility
If complex optical elements like microlens elements and prism structures are added to convert light angles, then viewing angle control is improved, but device complexity and light loss increase
Solution Approach 1:
The patent extracts the light extraction function from separate complex optical elements and integrates it directly into the light guide structure itself, eliminating the need for additional microlens elements and prism structures
Solution Approach 2:
The patent combines the light guiding function and the light extraction function into a single integrated structure, where the light guide's geometric design inherently provides both light transport and controlled angular extraction
3Adaptability or versatility
If special optical surfaces resembling Fresnel lenses are used to deflect light, then light direction control is improved, but manufacturing complexity increases and residual light problems occur
Solution Approach 1:
The patent changes from complex curved Fresnel lens surfaces to simpler planar or gently curved extraction surfaces with controlled micro-structures, achieving comparable light direction control with much simpler manufacturing
4Object-affected harmful factors
If light is scattered more aggressively to block viewing from certain angles, then privacy protection is improved, but brightness and image quality deteriorate
Solution Approach 1:
The patent applies light extraction only at specific locations and angles on the light guide surface, allowing light to maintain its intensity in desired viewing directions while being extracted in unwanted directions, thus protecting privacy without sacrificing brightness
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
Enables defined viewing of image contents from specific angular ranges with enhanced black-and-white contrast and reduced residual light, supporting dual-view modes and privacy applications with improved brightness and simplicity.
Implementation Method 1
a plate-shaped light guide (3) in front of the backlight unit (2) with outcoupling elements (6) wherein the number of outcoupling elements (6) per unit area and their extension are chosen so that the light guide (3), on at least 50% of its area, scatters at most 25%, preferably at most ten % of the light penetrating its large surfaces by more than ten degrees
Data Source
AI summary
An illuminating apparatus designed for a display screen and operable in at least two operating modes B1 and B2 and/or at least one operating mode B3 for illuminating separately two or simultaneously both, at least partially disjoint angular ranges W1 and W2, comprising a planar backlight unit, which in a first alternative radiates light into the said restricted angular range W2, and in a second alternative radiates light into a restricted angular range W2a, a plate-shaped light guide that is arranged in front of the backlight unit and features, on at least one of the large surfaces and/or within its volume, outcoupling elements, wherein the light guide is transparent to at least 70% of the light originating from the backlight unit, and light sources are arranged laterally on at least one of the narrow edges of the light guide.