Light Guide Concave Indentations for Display Homogeneity
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Solution Overview
Problem
Portable information handling systems with thin or no border displays face issues of inhomogeneous light intensity due to inefficient light distribution, leading to undesirable 'hot spots' and reduced overall illumination.
Innovation Solution
A light guide with concave indentations and a concave protrusion on its surfaces, combined with an anti-reflective or diffusive coating, is used to improve light diffusion and reflection, ensuring more uniform illumination by preventing light loss and enhancing light homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a thin or no border display design is used, then the device form factor is improved and made more compact, but light distribution becomes inhomogeneous causing hot spots and reduced illumination quality
Solution Approach 1:
The light guide features localized concave indentations at specific positions corresponding to light sources and a concave protrusion at the exit face. These localized structural modifications create variable light reflection and diffusion properties at different locations, transforming the uniform light guide into one with spatially varying optical characteristics that compensate for the inhomogeneous light distribution in thin display designs.
Solution Approach 2:
The patent employs curved surfaces including concave indentations and a concave protrusion instead of flat surfaces. The curved geometry of these features modifies light propagation paths through controlled reflection and refraction, enabling more uniform light distribution across the display area while maintaining the thin form factor.
2Volume of moving object
If conventional light guides are used in thin displays, then the device remains compact, but light loss occurs leading to reduced overall illumination
Solution Approach 1:
The concave protrusion at the exit face acts as a reflective structure that captures light which would otherwise be lost or escape uselessly. By converting what would be light loss into useful reflected light that re-enters the light guide, the structure transforms a harmful effect (light loss) into a beneficial outcome (enhanced illumination).
Solution Approach 2:
The concave indentations are positioned at the light input face to pre-process the light before it propagates through the guide. These indentations create initial diffusion and reflection patterns that prepare the light distribution, preventing concentration issues before they develop and reducing the need for additional light correction mechanisms.
3Volume of moving object
If light sources are positioned close to the display surface, then the display can be made thinner, but hot spots appear due to concentrated light intensity
Solution Approach 1:
The concave indentations are strategically positioned at locations corresponding to light sources to create localized light diffusion zones. This local modification approach addresses the hot spot problem specifically at the light source regions without requiring changes to the entire light guide structure, enabling thin design while eliminating concentrated light intensity issues.
Solution Approach 2:
The patent introduces vertical dimension variations through concave indentations and protrusions, transforming a two-dimensional flat light guide into a three-dimensional structure with controlled depth variations. This dimensional change enables light redistribution in the vertical direction, scattering concentrated light from sources and eliminating hot spots while maintaining overall thinness.
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 achieves improved light homogeneity and reduced light loss, providing more uniform illumination without hot spots, suitable for thin or no border display designs.
Implementation Method 1
a concave reflector bonded to the concave protrusion to reflect the light back into the light guide
Implementation Method 2
A light guide with concave indentations and a concave protrusion on its surfaces, combined with an anti-reflective or diffusive coating, is used to improve light diffusion and reflection
Data Source
AI summary
A display in a portable information handling system may have a narrow or no border. A light guide for display light enhancement used to illuminate the display may be formed with concave indentations at a first face that receives light from a light source, such as a string of light emitting diodes. The concave indentations may improve the homogeneity of light transmitted by the light guide. The light guide may further have a light diffusive surface treatment at the first face.