Semi-transmission LCD Overcoat Layer Refractive Index Optimization
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Solution Overview
Problem
Conventional semi-transmission LCD devices primarily operate in transmission mode due to higher light intake, limiting their effectiveness in reflection mode and increasing power consumption with the use of backlights, which are necessary for image display in dark environments.
Innovation Solution
A semi-transmission LCD device is enhanced by forming a concave overcoat layer on the color filter substrate, allowing for improved reflection efficiency of external light and transmission efficiency of backlight light, achieved through the use of a first overcoat layer with a higher refractive ratio and a second overcoat layer with a different chemical reaction and refraction ratio, enabling both reflection and transmission modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional semi-transmission LCD device operates in transmission mode to increase light intake, then light transmission efficiency is improved, but reflection efficiency deteriorates and power consumption increases due to backlight requirement
Solution Approach 1:
The overcoat layer is formed with different refractive indices in different regions: a first overcoat layer with refractive index n1 over the reflection electrode region, and a second overcoat layer with refractive index n2 over the light blocking electrode region, where n1 > n2. This local differentiation optimizes light reflection at the reflection electrode while maintaining light transmission control at the light blocking electrode, enabling efficient operation in both reflection and transmission modes without requiring constant backlight illumination.
2Use of energy by moving object
If a reflection LCD device uses external natural light or artificial light as an optical source to decrease power consumption, then power consumption is reduced, but usability in dark places deteriorates
Solution Approach 1:
The LCD device is designed to operate in both reflection mode and transmission mode through the differential overcoat layer structure. In reflection mode, it uses external light sources to conserve power. In transmission mode, it uses a backlight unit to enable operation in dark environments. The device thus achieves multi-functionality, adapting to different environmental conditions and usage scenarios.
3Ease of manufacture
If a conventional semi-transmission LCD device uses a flat overcoat layer, then manufacturing simplicity is maintained, but light reflection efficiency and transmission efficiency deteriorate
Solution Approach 1:
The overcoat layer is formed with different refractive indices in different regions: a first overcoat layer with refractive index n1 over the reflection electrode region, and a second overcoat layer with refractive index n2 over the light blocking electrode region, where n1 > n2. This local differentiation optimizes light reflection at the reflection electrode while maintaining light transmission control at the light blocking electrode, enabling efficient operation in both reflection and transmission modes.
Solution Approach 2:
The invention changes the refractive index parameter of the overcoat layer materials based on their functional requirements. The first overcoat layer uses material with higher refractive index (n1) to enhance light reflection, while the second overcoat layer uses material with lower refractive index (n2) to optimize light transmission control. This parameter optimization improves optical efficiency without significantly complicating the manufacturing process.
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 light reflection efficiency in reflection mode and reduces light loss in transmission mode, allowing for efficient use of both external and backlight light, thereby reducing power consumption and enabling operation in dark environments.
Implementation Method 1
a first overcoat layer having a first refraction ratio and a second overcoat layer having a second refraction ratio different from the first refraction ratio
Implementation Method 2
enhancing a reflection efficiency of light by introducing external light to a reflection portion on an array substrate
Data Source
AI summary
A semi-transmission LCD device capable of enhancing a reflection efficiency by introducing external light to a reflection portion on an array substrate of a thin film transistor forming an overcoating layer having concave portions on a color filter substrate, and capable of enhancing a transmission efficiency of light incident from a backlight, and a fabricating method thereof. The semi-transmission LCD device comprises: a first substrate; a second substrate; black matrixes formed on the second substrate with a predetermined gap therebetween; a color filter formed between the black matrixes; a common electrode formed on the color filter; an overcoat layer, having concave portions, formed on the common electrode; and an LC layer formed between the first substrate and the second substrate.