Transparent TFT Array Substrate for High PPI LCD Aperture Ratio

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Solution Overview

Problem

In high pixels per inch (PPI) liquid crystal display (LCD) panels, the area occupied by thin film transistors (TFTs) reduces the aperture ratio, leading to lower transmittance and poor display effects due to their opaque nature.

Innovation Solution

A TFT array substrate is designed with transparent silicon-based nanolines forming the semiconductor layer and a transparent gate electrode, along with a comb-shaped source and drain electrode structure, where the pixel electrode covers the TFT region, allowing backlight illumination to pass through, thereby increasing the aperture ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the PPI of LCD panel is increased, then the display resolution is improved, but the aperture ratio decreases due to larger TFT area occupation

Engineering Contradiction:

Improvedisplay resolutionVSAvoidaperture ratio

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent applies transparency changes to the gate electrode and semiconductor layer by using transparent conductive materials (such as ITO) for the gate electrode and silicon-based nanolines for the semiconductor layer. This allows light to pass through the TFT region, effectively increasing the aperture ratio while maintaining high PPI display resolution.

Inventive Principle:

Principle #32Color changes

2Measurement precision

If the TFT area in sub-pixel is increased to support high PPI, then the display resolution is improved, but the light transmittance decreases

Engineering Contradiction:

Improvedisplay resolutionVSAvoidlight transmittance

Core Design Contradiction:

Measurement precisionVSIllumination intensity

Solution Approach 1:

The gate electrode is made transparent using transparent conductive materials like ITO, and the semiconductor layer uses silicon-based nanolines that are transparent to light. This transparency design allows backlight to pass through the TFT region, maintaining high light transmittance even with increased TFT area for high PPI resolution.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent employs composite material structures including transparent conductive oxide (TCO) for the gate electrode, silicon-based nanolines for the semiconductor layer, and transparent passivation layers. These composite transparent materials enable the TFT to maintain electrical functionality while being optically transparent, thus preserving light transmittance in high PPI displays.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10877340B2TFT array substrate, fabrication method thereof and liquid crystal display panel

Publication Date: 2020.12.29 SHENZHEN CHINA STAR OPTOELECTRONICS SEMICON DISPLAY TECH CO LTD

AI summary

A TFT array substrate, a fabrication method thereof and a LCD panel are provided. The TFT array substrate adopts the transparent silicon-based nanolines to form the semiconductor layer of the TFT, adopts the transparent material to form the gate electrode of the TFT, and has the pixel electrode covering the region occupied by the TFT, such that the illumination emitted by the backlight can pass through the whole TFT and the pixel electrode, i.e. the pixel portion occupied by the TFT 20 is also transparent, and thus the aperture ratio can be significantly increased to enhance transmittance and display effect of high PPI LCD panels.