LCD Self-Testing via Internal High Voltage Generation
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Solution Overview
Problem
Conventional liquid crystal display (LCD) high voltage stress testing requires a separate apparatus, increasing manufacturing costs and complicating the testing procedure.
Innovation Solution
An LCD with an internal connector system that self-generates high voltage for testing by adjusting gate-on and gate-off voltages based on the electrical connection or disconnection between the no-connect pin and ground pin, eliminating the need for external testing apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate HVS testing apparatus is used to provide high voltage for testing, then the LCD can be tested for high voltage stress, but the manufacturing cost increases and the testing procedure becomes complicated
Solution Approach 1:
The LCD is designed to self-generate high voltage for testing using its own internal components. The power supply unit utilizes the existing power supply voltage and switching elements to create the necessary high gate-on and low gate-off voltages for HVS testing, eliminating the need for external testing apparatus. This self-service approach resolves the contradiction by maintaining testing capability while removing the requirement for separate testing equipment.
Solution Approach 2:
The power supply unit is designed to perform multiple functions: it provides normal operating voltages during regular LCD operation and simultaneously generates high voltage stress test conditions when the NC pin is connected to ground. This multi-functionality allows the same circuit to serve both operational and testing purposes, reducing device complexity while maintaining reliability.
2Reliability
If a separate HVS testing apparatus is used, then high voltage can be applied to the LCD for testing, but manufacturing costs increase
Solution Approach 1:
The LCD uses its own internal power supply unit and switching elements to generate the high voltage needed for testing. By utilizing existing components (power supply voltage, switching elements, and capacitors) already present in the LCD, the design eliminates the need to purchase and integrate separate external testing apparatus, thereby reducing manufacturing costs while maintaining testing functionality.
Solution Approach 2:
The testing functionality is merged with the existing power supply unit. The power supply unit is modified to include testing-specific voltage generation capabilities using the same physical components used for normal operation. This merging of functions reduces the total component count and simplifies manufacturing processes while ensuring the LCD can be properly tested.
3Reliability
If a separate HVS testing apparatus is used, then the LCD can undergo high voltage stress test, but the testing procedure becomes complicated
Solution Approach 1:
The LCD automatically generates the necessary high voltage conditions for stress testing through its internal power supply unit when the NC pin is connected to ground. This self-service mechanism simplifies the testing procedure by eliminating the need for external testing equipment and complex manual setup, allowing testers to simply connect the NC pin to ground and initiate the test through standard testing software.
Solution Approach 2:
The power supply unit is pre-configured with testing capabilities that activate automatically when the NC pin is connected to ground. The high voltage generation circuitry is prepared in advance within the power supply unit, so when testing is initiated, the system automatically transitions to testing mode without requiring manual configuration or external apparatus setup, thereby simplifying the testing procedure.
Data Source
AI summary
A liquid crystal which self-generates a high voltage for a high voltage stress test, a connector for testing the liquid crystal display and a method of testing the liquid crystal display include an internal connector having an input pin which receives a power supply voltage from an outside source, a no-connect pin, a ground pin and a power supply unit connected to the no-connect pin and the ground pin. The power supply unit receives the power supply voltage and outputs a gate-on voltage and a gate-off voltage whose levels are adjusted according to whether there is an electrical connection between the no-connect pin and the ground pin. Agate driving unit receives the gate-on voltage and the gate-off voltage and outputs a gate signal and a liquid crystal panel having a plurality of pixels receives the gate signal and displays images in response to the gate signal.