Light Guide Element Brightness Uniformity in Display Devices
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Solution Overview
Problem
Current display devices with polymer-dispersed liquid crystal layers face challenges in maintaining display quality due to rapid brightness decrease in regions distant from light-emitting elements, caused by undesirable absorption and scattering by various elements within the substrates.
Innovation Solution
Incorporation of a light guide element with a transparent substrate and a low refractive index layer, where the light-emitting elements are aligned to oppose the side surface of the transparent substrate, and the light guide element includes a transparent layer with a refractive index lower than the substrate, promoting efficient light entry and reducing attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light-emitting elements are disposed within the substrates, then the display device can achieve compact structure and effective light utilization, but brightness decreases rapidly in regions distant from the light-emitting elements due to absorption and scattering
Solution Approach 1:
A light guide element comprising a transparent substrate and a transparent layer with lower refractive index is introduced as an intermediary between the light-emitting element and the display panel. The transparent layer has a refractive index lower than both the transparent substrate and the adhesive layer, creating optimal refraction conditions that reduce light scattering and absorption, thereby maintaining brightness over longer distances.
Solution Approach 2:
The refractive index parameter is optimized by selecting materials with specific refractive index relationships: the transparent layer has a lower refractive index than both the transparent substrate and the adhesive layer. This parameter optimization minimizes light refraction losses and scattering, enabling effective light transmission to regions distant from the light-emitting element.
2Illumination intensity
If multiple layers with different refractive indices are used to improve light transmission, then brightness maintenance is improved, but device complexity increases
Solution Approach 1:
The transparent layer serves multiple functions simultaneously: it acts as an optical medium with optimized refraction properties, provides adhesive bonding between the transparent substrate and display panel, and offers protective coverage. This multi-functionality reduces the need for separate functional layers, maintaining brightness improvement while limiting complexity increase.
3Illumination intensity
If the transparent layer has a refractive index lower than the transparent substrate, then light entry efficiency is improved and brightness is maintained, but manufacturing precision requirements increase
Solution Approach 1:
The refractive index parameter is strategically optimized by selecting materials where the transparent layer has a lower refractive index than both the transparent substrate and adhesive layer. This parameter configuration creates favorable refraction conditions that enhance light entry efficiency while working within practical manufacturing capabilities through proper material selection.
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 enhances display quality by maintaining brightness across regions distant from light-emitting elements, suppressing sudden brightness drops and allowing for better heat dissipation and moisture protection, while improving physical strength.
Implementation Method 1
a transparent layer disposed on the main surface and having a refractive index lower than that of the transparent substrate
Implementation Method 2
there is a demand for further improving the display quality... suppressing sudden brightness drops
Data Source
AI summary
According to one embodiment, a display device includes a first substrate, a second substrate, a liquid crystal layer, a first light guide element and a light-emitting element. The liquid crystal layer contains stringy polymers and liquid crystal molecules. The first light guide element includes a third transparent substrate including a side surface and a main surface, and a transparent layer disposed on the main surface and having a refractive index lower than that of the third transparent substrate. The light-emitting element opposes the side surface, and the third transparent substrate is adhered to the second transparent substrate while interposing the transparent layer therebetween. The light-emitting element is disposed on the second transparent substrate.