Liquid Crystal Display Reducing External Light Reflection
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Solution Overview
Problem
Conventional liquid crystal display devices with a TFT substrate on the viewing surface side experience high reflectance due to metal lines and multilayer film interference, making it difficult to view transmissive displays in environments with external light.
Innovation Solution
Incorporating a circularly polarizing plate with a λ/4 retardation layer on the viewing surface side and a reflective layer on the color filter substrate to reduce external light reflection, along with a second λ/4 retardation layer and a shield electrode to enhance display quality and luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a TFT substrate is disposed on the viewing surface side to increase luminance, then luminance is improved, but external light reflection increases
Solution Approach 1:
The patent converts the harmful reflection from the TFT substrate into a beneficial effect by introducing a circularly polarizing plate that transforms reflected linearly polarized light into circularly polarized light, which is then absorbed by the liquid crystal layer, turning the harmful reflection into a mechanism that enhances display quality
Solution Approach 2:
The circularly polarizing plate acts as an intermediary between the TFT substrate and the liquid crystal layer, mediating the interaction between external light and the display structure by converting polarization states and reducing the direct harmful effect of reflections
2Adaptability or versatility
If metal lines and multilayer structures are used in the TFT substrate, then electrical functionality is improved, but light reflection increases
Solution Approach 1:
The patent converts the harmful reflection from metal lines and multilayer structures into a beneficial effect by using the circularly polarizing plate to transform the reflected light into circular polarization, which is then absorbed by the liquid crystal layer, turning structural reflections into a mechanism that enhances display quality
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 suppresses external light reflection, improving transmissive display quality and luminance while maintaining favorable viewing angle characteristics, even in bright environments.
Implementation Method 1
a circularly polarizing plate with a λ/4 retardation layer on the viewing surface side
Implementation Method 2
effectively suppresses external light reflection
Implementation Method 3
a reflective layer disposed outside the pixel region and configured to reflect incident light from the backlight toward the back surface
Implementation Method 4
The liquid crystal molecules rotate in the in-plane direction according to the electric field generated in the liquid crystal layer 40 in the state where voltage is applied between the paired electrodes
Data Source
AI summary
The liquid crystal display device includes, sequentially from a viewing surface side to a back surface side: a linearly polarizing plate and a circularly polarizing plate including a first λ/4 retardation layer; a thin-film transistor substrate including a pair of electrodes disposed in a pixel region and a metal line disposed outside the pixel region; a liquid crystal layer containing liquid crystal molecules aligned parallel to the thin-film transistor substrate, alignment of the liquid crystal molecules varying in response to an electric field generated by application of voltage to the pair of electrodes; a color filter substrate including a color filter layer; and a backlight, the thin-film transistor substrate including a second λ/4 retardation layer, the color filter substrate including a reflective layer disposed outside the pixel region and configured to reflect incident light from the backlight toward the back surface.