LCD Inspection Terminals via Laser Welded Conductive Film
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Solution Overview
Problem
In liquid crystal displays using the COG method, it is difficult to investigate the cause of display failures such as line defects due to the insulating layer covering the wires, and existing solutions require extending wires or exposing electrodes, leading to increased wire resistance and corrosion issues.
Innovation Solution
A liquid crystal display design that includes a conductive film pattern on the wires in the peripheral portion of the substrate, covered by an insulating layer, allowing for the inspection of output signals and waveforms without extending wires or exposing electrodes, using laser welding for failure analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If the output-side wire is extended and the electrode portion is exposed for inspection, then the cause of display failure can be investigated, but wire corrosion is induced and reliability deteriorates
Solution Approach 1:
The patent introduces an intermediary measurement wire that extends from the output-side wire through the driver LSI to an external measurement electrode. This intermediary structure allows failure investigation without exposing the original output electrode, thus preventing corrosion while enabling measurement. The measurement wire acts as a mediator between the internal circuit and external measurement equipment.
Solution Approach 2:
The patent transitions the measurement approach from a two-dimensional surface exposure (exposed electrode on the panel surface) to a three-dimensional routing through the substrate thickness. The measurement wire passes through the driver LSI and exits at the rear surface, utilizing the Z-dimension (thickness direction) to achieve external accessibility without surface exposure.
2Ease of manufacture
If the input-side wire is extended to connect to the short side of the driver LSI, then connection is achieved, but wire resistance increases and signal quality deteriorates
Solution Approach 1:
The patent performs preliminary routing of the measurement wire through the driver LSI during the manufacturing process, before final assembly. The wire is pre-positioned and connected to internal circuits, allowing short connection paths to be established in advance rather than requiring long external routes that would increase resistance.
3Reliability
If the wires are covered with insulating layer for protection, then corrosion is prevented, but inspection of wire connections becomes difficult
Solution Approach 1:
The patent segments the wire structure into multiple parts: the protected internal portion covered by insulating layer, the measurement wire extending through the driver LSI, and the external measurement electrode. This segmentation allows the main wire to remain protected while the measurement portion provides inspection capability without requiring exposure of the protected sections.
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
Enables easy inspection of output signals and waveforms by providing terminals for failure analysis without extending wires or exposing electrodes, reducing wire resistance and preventing corrosion, thus improving the efficiency and reliability of failure diagnosis.
Implementation Method 1
it is possible to provide terminals used for investigating the cause of failure without extending the wires or exposing electrode portions connected to the wires and this produces an effect of making it possible to easily inspect an output signal or an output waveform of the driver LSI only by welding a predetermined portion with a laser
Data Source
AI summary
A liquid crystal display of the present invention comprises a display portion having two opposed insulating substrates (an electrode substrate (1) and an opposed substrate 2) holding a liquid crystal layer to form a plurality of display elements, wires (3a) formed on at least one of the insulating substrates, for supplying signals to the plurality of display elements, a driver LSI (6) provided in a peripheral portion of the insulating substrate, being connected to terminals of the wires (3a, 3b) to drive a plurality of display elements, and a conductive film pattern portion formed on the wires (3a) in the peripheral portion of the insulating substrate with a first insulating layer interposed therebetween. With this constitution, a liquid crystal display which allows inspection of output signals of the driver LSI in a failure analysis, without extending wires or exposing electrode portions connected to the wires and a method of inspecting the liquid crystal display are provided.