Flat Panel Display Link Pixel Compensation Circuit
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Solution Overview
Problem
Flat panel displays, such as LCDs and OLEDs, suffer from defective pixels caused by signal wire line shorts or TFT defects, which are difficult to recognize and repair, especially in gray scale levels, leading to brightness spots that affect picture quality.
Innovation Solution
A method and apparatus that electrically connects a normal pixel to a defective pixel to form a link pixel, using compensation data to modulate digital video data and adjust charging characteristics, allowing the link pixel to display the same color as the defective pixel, thereby compensating for its defects and improving picture quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a defective pixel is darkened in a repairing process, then the defective pixel can be identified, but the defective pixel is hardly recognized in black gray scale level and only recognized as a dark spot in middle and white gray scale levels
Solution Approach 1:
The patent changes the electrical charging parameters of the defective pixel by connecting it to a normal pixel through a link pixel, allowing charge sharing between pixels. This parameter change enables the defective pixel to display the same brightness as normal pixels in certain gray scale levels, making it harder to detect while maintaining visibility in others.
Solution Approach 2:
The patent introduces a link pixel as an intermediary between the defective pixel and the normal pixel. This link pixel facilitates charge transfer and enables the defective pixel to borrow charge from the normal pixel, thereby compensating for the defective pixel's charging characteristics and reducing its visibility as a brightness spot.
2Reliability
If a defective pixel is electrically connected to a normal pixel to form a link pixel, then the charging characteristics can be compensated, but the device complexity increases due to additional connection and compensation circuits
Solution Approach 1:
The patent merges the compensation function with the existing pixel structure by forming a link pixel that combines a defective pixel and a normal pixel into a single functional unit. This merging approach allows the defective pixel to share charge with the normal pixel, compensating for its charging characteristics without requiring a completely separate compensation system.
Solution Approach 2:
The link pixel serves multiple functions: it acts as both a defective pixel and a normal pixel, enabling charge sharing while maintaining display functionality. This multi-functionality reduces the need for additional dedicated compensation components, thereby limiting the increase in device complexity while improving picture quality.
3Manufacturing precision
If compensation data is stored in memory and used to modulate digital video data, then the charging characteristics of the link pixel can be precisely controlled, but the manufacturing precision requirements increase for data storage and modulation
Solution Approach 1:
The patent performs preliminary measurement of the link pixel's charging characteristics during manufacturing and stores this compensation data in memory before the display is put into service. This preliminary action allows the compensation data to be pre-calculated and stored, eliminating the need for complex real-time calculations and reducing the precision requirements during actual operation.
Solution Approach 2:
The patent uses feedback from the measured charging characteristics of the link pixel to determine the compensation data stored in memory. This feedback mechanism ensures that the compensation data accurately reflects the actual charging behavior of the link pixel, maintaining precision while simplifying the manufacturing process by using stored reference values rather than requiring continuous high-precision control.
Data Source
AI summary
A flat panel display, a fabricating method thereof, a fabricating apparatus thereof, a picture quality controlling method thereof and a picture quality controlling apparatus for reducing a recognizing degree of a defective pixel and electrically compensating a charging characteristics of the defective pixel are provided.In the flat panel display, a display panel has a plurality of pixels. A defective pixel is electrically connected to an adjacent normal pixel. A memory stores a location data that indicates a location of the link pixel and a compensation data that compensates for charging characteristics of the link pixel. A compensation circuit modulates a digital video data to be displayed on the link pixel on the basis of the location data and the compensation data.