Light Guide Panel Incident Surface Geometry for Higher Light Extraction
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Solution Overview
Problem
The existing image display devices using light guide plates suffer from reduced light emission due to increased thickness and decreased reflection from the bottom surface of the light guide plate.
Innovation Solution
The image display device incorporates a light guide panel with a concave portion on its incident surface and inclined main surfaces on its bottom surface, which increases the refraction angle of incident light and enhances light reflection and emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If two types of inclined surfaces are formed on the light guide plate to reduce light reflection from the bottom surface, then the light extraction efficiency is improved, but the thickness of the light guide plate is increased and the amount of light emitted from the output surface is reduced
Solution Approach 1:
The patent applies local quality by forming a concave portion only at the incident surface where light enters the light guide plate, rather than modifying the entire light guide plate structure. This localized modification changes the refraction characteristics specifically at the entry point, allowing light to be redirected at appropriate angles to increase bottom surface reflection opportunities without requiring overall thickness increase. The concave portion creates a focal region that optimizes light distribution while maintaining the light guide plate's overall thin profile.
Solution Approach 2:
The patent introduces a dimensional change by creating a concave portion with depth variation on the incident surface. This adds a third dimension (depth) to the otherwise planar incident surface, enabling light rays to be refracted at different angles depending on their position within the concave structure. This dimensional modification allows the system to achieve improved light extraction efficiency without increasing the light guide plate's thickness in the primary direction.
2Loss of energy
If the thickness of the light guide plate is increased to reduce light reflection from the bottom surface, then the light extraction efficiency is improved, but the amount of light emitted from the output surface is reduced
Solution Approach 1:
The patent applies local quality by forming a concave portion only at the incident surface where light enters the light guide plate, rather than modifying the entire light guide plate structure. This localized modification changes the refraction characteristics specifically at the entry point, allowing light to be redirected at appropriate angles to increase bottom surface reflection opportunities without requiring overall thickness increase. The concave portion creates a focal region that optimizes light distribution while maintaining the light guide plate's overall thin profile.
3Loss of energy
If the thickness of the light guide plate is increased to reduce light reflection from the bottom surface, then the light extraction efficiency is improved, but the device complexity is increased
Solution Approach 1:
The patent applies local quality by forming a concave portion only at the incident surface where light enters the light guide plate, rather than modifying the entire light guide plate structure. This localized modification changes the refraction characteristics specifically at the entry point, allowing light to be redirected at appropriate angles to increase bottom surface reflection opportunities without requiring overall thickness increase. The concave portion creates a focal region that optimizes light distribution while maintaining the light guide plate's overall thin profile.
Solution Approach 2:
The patent employs curvature by forming a concave portion on the incident surface, which introduces a curved geometric feature to an otherwise planar structure. This curvature is designed with specific dimensional parameters (depth and width ratios) to optimize light refraction and reflection characteristics. The curved surface enables more effective light manipulation compared to flat surfaces, achieving improved light extraction efficiency with a relatively simple structural modification.
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
This configuration increases the amount of light emitted from the output surface, improving the overall light extraction efficiency and luminance of the image display device.
Implementation Method 1
The incident surface of the light guide panel has a concave portion, having a predetermined length facing a center of a light emitting surface of the light source unit, in which a part of the incident surface is recessed from remaining portions
Implementation Method 2
the thickness of the light guide plate is increased and the chance of light being reflected by the bottom surface of the light guide plate is reduced
Data Source
AI summary
An image display device includes a light source unit, a display panel configured to display an image, and a light guide panel configured to guide light emitted from the light source unit to the display panel. The light guide panel has an incident surface facing the light source unit, an output surface facing the display panel, and a bottom surface facing the output surface on a side opposite to the display panel. The incident surface is a side surface of the light guide panel located between the output surface and the bottom surface. The incident surface has a concave portion in which a part of the incident surface is recessed from remaining portions when viewed from a direction perpendicular to a light guide direction of light in the incident surface and an emission direction of light in the output surface.