2D/3D Switchable Backlight Unit Using Frustrated Total Internal Reflection
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Solution Overview
Problem
Current 3D image display devices without glasses require a switching mechanism to toggle between 2D and 3D modes, but existing solutions are cumbersome and lack efficient light utilization, leading to brightness loss in 3D mode.
Innovation Solution
A 2D/3D switchable backlight unit utilizing a light guide plate with a switch array that employs frustrated total internal reflection, where switches selectively contact the light guide plate to emit light, and a lens array directs light to different view zones, allowing for seamless 2D/3D mode switching with minimal brightness loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switching device is used to toggle between 2D and 3D images, then 3D image display capability is achieved, but device complexity increases
Solution Approach 1:
The backlight unit is segmented into multiple independently controllable light emitting regions corresponding to different view zones. Each region can be activated or deactivated based on the display mode (2D or 3D), enabling mode switching without requiring a complex external switching device. The light guide plate is divided into multiple regions with respective light emitting portions that can be selectively controlled.
2Adaptability or versatility
If light is emitted in 3D mode, then 3D image display is enabled, but brightness is lost due to inefficient light utilization
Solution Approach 1:
Different regions of the light guide plate are designed with different light emitting characteristics. In 3D mode, specific local regions (light emitting portions) are activated to emit light toward different view zones, while other regions remain inactive. This local activation ensures that light is efficiently directed only where needed, preventing brightness loss and maintaining high illumination intensity in the active view zones.
Solution Approach 2:
The light emitting characteristics of the backlight unit are dynamically adjusted based on the display mode. In 2D mode, the entire light guide plate emits light uniformly. In 3D mode, the light emitting portions are dynamically activated or deactivated based on the current view zone, enabling dynamic adaptation to different display requirements and maintaining optimal brightness levels.
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 enables efficient light utilization and prevents brightness loss in 3D mode by using frustrated total internal reflection, allowing for compact and effective 2D/3D image display without the need for glasses.
Implementation Method 1
a light guide plate in which light emitted from the light source is total-internal-reflected
Implementation Method 2
emit light by frustrated total internal reflection inside the light guide plate
Data Source
AI summary
A 2D/3D switchable backlight unit and an image display device employing the same are provided. The 2D/3D switchable backlight unit includes a light source, a light guide plate in which light emitted from the light source is total-internal-reflected, and a switch array comprising a plurality of switches that selectively contact a first surface of the light guide plate and emit light by frustrated total internal reflection inside the light guide plate. In 2D mode, each of the switches contacts the first surface of the light guide plate. In 3D mode, some of the switches contact the first surface of the light guide plate.