Pixel Electrodes on Substrate for Liquid Crystal Displays

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Solution Overview

Problem

The manufacturing process of active matrix substrates for liquid crystal display devices is hindered by thermal restrictions on semiconductor layers, leading to increased costs and reduced efficiency in forming pixel electrodes and wiring lines.

Innovation Solution

The pixel electrodes are formed on a substrate layer separate from the semiconductor layer, allowing for a thermal treatment without affecting the semiconductor layers, and using a liquid phase method with banks to define the electrode regions, enabling a simpler and cost-effective manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If pixel electrodes are formed on semiconductor layers, then the electrodes can be integrated with switching elements, but thermal restrictions prevent the use of liquid phase forming methods and increase manufacturing costs

Engineering Contradiction:

Improvemanufacturing costVSAvoidprocess complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent divides the formation process into two independent stages: first forming pixel electrodes on the substrate, then forming semiconductor layers on top. This segmentation allows each stage to use optimal forming methods without thermal interference, enabling liquid phase methods for electrodes while maintaining standard processes for semiconductor layers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pixel electrodes are formed in advance before the semiconductor layers are deposited. This preliminary action allows the electrodes to be formed using liquid phase methods at lower temperatures, avoiding the thermal restrictions that would exist if electrodes were formed after high-temperature semiconductor processing.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If thermal treatment is applied to form pixel electrodes, then conductivity can be improved, but the semiconductor layers are damaged due to hydrogen desorption

Engineering Contradiction:

Improveelectrode conductivityVSAvoidhydrogen desorption from semiconductor

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent protects the semiconductor layers by forming them after the electrodes, so they are not exposed to thermal treatment. Alternatively, low-temperature forming methods are used for electrodes that do not cause hydrogen desorption from the semiconductor layers, cushioning them from thermal damage while still achieving adequate electrode conductivity.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If pixel electrodes are formed after semiconductor layers, then integration is simplified, but the forming method is restricted and costs increase

Engineering Contradiction:

Improveforming method flexibilityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Instead of the conventional sequence of forming semiconductor layers first and then pixel electrodes, the patent inverts the sequence by forming pixel electrodes on the substrate first, then depositing semiconductor layers. This inversion removes thermal restrictions on electrode formation, allowing versatile liquid phase methods and reducing manufacturing costs.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS7567309B2Pixel electrodes and switching elements formed on same substrate in openings of insulating film formed on the substrate

Publication Date: 2009.07.28 138 EAST LCD ADVANCEMENTS LTD

AI summary

A pixel structure includes pixel electrodes and switching elements which correspond to the pixel electrodes. The pixel electrodes and the switching elements are formed on the same substrate, and each pixel electrode is provided in a layer on the substrate, not on a semiconductor layer of the switching element.