Light Guide Module for Uniform Illumination in PDLC Displays
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Solution Overview
Problem
In display devices with polymer dispersed liquid crystal layers, light emitted from light-emitting elements is not sufficiently mixed near the light guide, leading to visible stripe-shaped irregularities in luminance due to insufficient scattering of light.
Innovation Solution
A light-emitting module is integrated with a light guide and reflectors disposed on its surfaces, which are bonded to a wiring substrate and the display panel, ensuring that light is diffused and reflected to uniformly illuminate the display area, thereby reducing luminance irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light-emitting elements are arranged at intervals to illuminate the display panel, then the display panel can be illuminated, but light is not sufficiently mixed near the light guide plate causing stripe-shaped luminance irregularities
Solution Approach 1:
A light guide plate is introduced as an intermediary component between the light-emitting elements and the display panel. The light guide plate receives light from the light-emitting elements and distributes it uniformly across the display panel through its light-guiding properties, preventing direct illumination patterns and stripe-shaped luminance irregularities.
Solution Approach 2:
The patent replaces direct mechanical/optical contact between light-emitting elements and the display panel with a light guide plate system. This substitution allows light to be transmitted and diffused through the light guide plate's optical properties rather than direct emission, achieving more uniform illumination.
2Loss of energy
If light-emitting elements are placed close to the display panel for efficient illumination, then light use efficiency improves, but light scattering is insufficient causing visible stripe irregularities
Solution Approach 1:
The light guide plate serves as a mediator that decouples the positioning requirements. Light-emitting elements can be positioned close to the light guide plate for efficient light coupling, while the light guide plate itself distributes the light uniformly across the display panel, eliminating stripe irregularities.
Solution Approach 2:
The light guide plate extends the light distribution in the lateral dimension across the display panel. By receiving light at one location and distributing it across a broader area through its planar structure, the system achieves uniform illumination without requiring precise positioning of multiple light-emitting elements.
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 mixes light emitted from adjacent light-emitting elements, suppressing stripe-shaped display irregularities and improving light use efficiency, resulting in enhanced display quality and reduced power consumption.
Implementation Method 1
Light emitted from a plurality of light-emitting elements arranged at intervals propagate through the light guide plate while being diffused in the light guide plate
Implementation Method 2
a reflector which is disposed on each of the first surface and the second surface
Data Source
AI summary
According to one embodiment, a display device includes a display panel including a polymer dispersed liquid crystal layer, and a light-emitting module disposed along a side surface of the display panel. The light-emitting module includes a light-emitting element, a light guide disposed between the light-emitting element and the side surface, and a reflector. The light guide has a first surface and a second surface facing each other, a third surface facing the light-emitting element, and a fourth surface facing the side surface. The reflector is disposed on each of the first surface and the second surface.