Edge-Type Backlight Unit With Undercut Light Guide Plate
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Solution Overview
Problem
Edge type backlight units in LCD devices suffer from brightness differences and increased non-display areas due to the limited emission angle of LEDs, which affects uniformity and external appearance.
Innovation Solution
A light guide plate with undercut spaces and specific reflection surfaces is used to accommodate LEDs, converting spotted light into two-dimensional light and improving brightness uniformity while reducing non-display areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LEDs are used as spotted light sources in edge type backlight units, then the light source can be compact and energy-efficient, but brightness uniformity deteriorates due to limited emission angle
Solution Approach 1:
The patent transitions from a two-dimensional light distribution problem to a three-dimensional solution by creating an undercut space that extends vertically beneath the light guide plate. This allows the LED to be positioned in a lower layer, changing the spatial dimension of light emission and enabling uniform light distribution across the display area while maintaining the compact LED structure.
Solution Approach 2:
The light guide plate acts as an intermediary element that receives spotted light from the LED and transforms it into uniform two-dimensional light. The plate's specific refractive index and structured surface (including the undercut space) mediate the light transformation process, converting the limited emission angle LED output into uniform illumination across the entire display area.
2Illumination intensity
If LEDs are disposed separate from light guide plate by fixed distance, then light distribution can be controlled, but non-display area increases requiring critical side space
Solution Approach 1:
The patent implements a nested structure where the LED is positioned within an undercut space that is formed by removing material from the light guide plate itself. This nesting allows the light source to be embedded within the optical structure, eliminating the need for separate mounting spaces and reducing the overall non-display area while maintaining proper light distribution control.
Solution Approach 2:
The solution moves the LED placement from a planar arrangement to a vertical arrangement by creating an undercut space. This dimensional change allows the LED to be positioned directly beneath the light guide plate in the vertical dimension, eliminating the need for lateral spacing and reducing the critical side space required for edge type backlight units.
3Length of stationary object
If edge type backlight unit structure is used, then LCD device can be made thinner, but non-display area increases at edges
Solution Approach 1:
The light source is nested within the light guide plate structure through the undercut space, eliminating the need for separate mounting structures that would increase non-display area. This nested configuration allows the backlight unit to maintain thin profile while minimizing edge non-display areas by integrating all components within the light guide plate's volume.
Solution Approach 2:
The patent merges the light source mounting structure with the light guide plate itself by forming the undercut space directly in the plate. This consolidation eliminates separate components and mounting structures, reducing the overall non-display area while maintaining the thin profile characteristic of edge type backlight units.
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 enhances brightness uniformity and reduces non-display areas, improving the external appearance of LCD devices by effectively managing LED placement and light distribution.
Implementation Method 1
a light guide plate configured to primarily and secondarily reflect light from the light source and to convert the reflected light into two dimensional light
Data Source
AI summary
Disclosed is a backlight unit provided with an improved external appearance and uniform brightness is disclosed. The backlight unit includes a light source, and a light guide plate configured to primarily and secondarily reflect light from the light source and to convert the reflected light into two dimensional light. One side portion of the light guide plate is formed to provide an undercut space enough to accommodate the light source.