Directional Backlight Unit Diffractor Light Leakage Control
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Solution Overview
Problem
Existing 3D image display apparatuses using directional backlight units face light leakage issues due to light escaping between the light guide plate and the display panel, leading to reduced light intensity.
Innovation Solution
A directional backlight unit is designed with a light guide plate, a diffractor with gratings on its exit surface, and a reflection plate on the edge of the exit surface, where the diffractor is not provided, made of metal or dielectric materials like silver, gold, or aluminum, to control the exit direction of light and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light is guided through a light guide plate using total reflection, then light can be directed towards the display panel, but light leaks between the light guide plate and display panel causing reduced intensity
Solution Approach 1:
The patent applies the reflection plate to convert the harmful light leakage into beneficial reflected light. The reflection plate is positioned at the interface between the light guide plate and display panel to reflect leaked light back into the light guide plate, transforming the energy loss into useful light that continues to be guided to the display panel, thereby resolving the contradiction between maintaining high light intensity and preventing energy loss.
2Ease of operation
If a diffractor is provided on the entire exit surface of the light guide plate, then light exit direction can be controlled, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by providing the diffractor only on a specific region of the exit surface rather than the entire surface. The diffractor is positioned to control light exit direction in the critical area where light needs to be directed towards the display panel, while the rest of the exit surface can be simpler to manufacture. This regional approach maintains effective light direction control while reducing manufacturing complexity.
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 effectively reduces light leakage by directing light through the diffractor, enhancing the intensity and quality of the 3D image displayed, while the reflection plate ensures that light is either reflected back into the light guide plate or output through the diffractor, minimizing losses.
Implementation Method 1
When light proceeds in a light guide plate due to total reflection
Implementation Method 2
A directional backlight unit may display a 3D image by adjusting an exit direction of light by using gratings
Implementation Method 3
a reflection plate provided on at least a part of the exit surface of the light guide plate
Data Source
AI summary
There are provided a backlight unit, a 3D image display apparatus, and a method of manufacturing the same. The backlight unit may include a light source, a light guide plate that guides light irradiated from the light source, and including an exit surface through which the light exits, and a reflection plate provided on at least a part of the exit surface of the light guide plate.