Liquid Crystal Display Capacitance Measurement Tag Structure
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Solution Overview
Problem
The manufacturing costs of liquid crystal displays with field generating electrodes on one substrate are increased due to the need for separate photomasks for each electrode, and there is a challenge in effectively measuring the capacitance of these displays to ensure quality and performance.
Innovation Solution
A liquid crystal display design where a common voltage applying portion, a pixel voltage applying portion, and a tag portion are formed using the same process as the display area, allowing for simultaneous formation of the common electrode and passivation layer, and a method to measure capacitance by applying different voltages to these portions, with the tag portion having the same thickness and structure as the display area, enabling capacitance measurement without additional masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate photomasks are used to form each field generating electrode, then manufacturing precision is improved, but manufacturing cost increases
Solution Approach 1:
The common electrode and passivation layer are formed simultaneously using a single photomask, merging two previously separate formation processes into one. This reduces manufacturing cost while maintaining precision through the integrated formation method described in the patent
Solution Approach 2:
The single photomask serves multiple functions by defining both the common electrode pattern and the passivation layer pattern simultaneously. This multi-functional approach eliminates the need for separate masks while achieving precise formation of both structures
2Measurement precision
If a measuring unit is added to measure capacitance, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The measuring unit is segmented into distinct functional portions (common voltage applying portion, pixel voltage applying portion, and tag portion) that are integrated into the existing display structure. This segmentation allows for precise capacitance measurement without requiring a completely separate complex measurement system
Solution Approach 2:
The measuring unit is nested within the display panel structure, with the common voltage applying portion, pixel voltage applying portion, and tag portion integrated alongside the display area structures. This nesting approach enables measurement functionality without adding external complexity to the overall device
Data Source
AI summary
A liquid crystal display including: a display area which includes an upper substrate, a lower substrate, pixels and a liquid crystal layer interposed between the upper and lower substrates; and a measuring unit including a tag portion, a common voltage applying portion, and a pixel voltage applying portion, in which the common voltage applying portion and the tag portion, and the pixel voltage applying portion and the tag portion are connected to each other, a data conductor, a common electrode, a passivation layer, and a pixel electrode are disposed on the common voltage applying portion with substantially the same thickness as at least one of the pixels of the display area, a first part of the data conductor of the common voltage applying portion directly contacts the pixel electrode, and a second part of the data conductor of the common voltage applying portion directly contacts the common electrode.