Tiled Passive-Matrix EL Display Boundary Luminance Control
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Solution Overview
Problem
Existing passive matrix electro-luminescent displays face challenges with visible luminance artifacts at the boundaries between adjacent tiles when using multiline drive methods, limiting the size and resolution of tiled displays due to power consumption issues and luminance differences between tiles.
Innovation Solution
A tiled passive-matrix EL display design that distributes luminance errors across multiple rows rather than concentrating them at the boundaries, using a controller to simultaneously drive multiple rows and column drivers across tiles, adjusting drive signals to minimize luminance variations and power consumption, while forming larger displays without objectionable artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiline drive methods are used to reduce power consumption, then power dissipation is reduced, but luminance artifacts appear at tile boundaries
Solution Approach 1:
The patent applies local quality by treating boundary rows differently from interior rows. Boundary rows are driven with reduced intensity or delayed timing compared to interior rows, creating locally adapted drive conditions that prevent luminance artifacts at tile boundaries while maintaining overall power efficiency through multiline driving
Solution Approach 2:
The patent implements preliminary anti-action by preemptively adjusting the drive signals for boundary rows before they are fully activated. The controller applies compensation signals or timing adjustments in advance to counteract the luminance discrepancies that would otherwise appear at tile boundaries, preventing the artifacts rather than correcting them after occurrence
2Area of stationary object
If display size is increased by tiling, then display area is increased, but visible boundaries and luminance differences appear between adjacent tiles
Solution Approach 1:
The patent merges multiple EL tiles into a single integrated display system where the controller coordinates drive signals across all tiles. By combining the driving control of multiple tiles and applying uniform timing and intensity adjustments across boundary rows, the system creates a unified visual output that eliminates visible boundaries while maintaining the benefits of tiled construction for large display area
3Device complexity
If one line is driven at a time in passive matrix displays, then device complexity is reduced, but power consumption increases significantly
Solution Approach 1:
The patent implements periodic action by systematically cycling through multiple rows in a predetermined sequence rather than driving one row at a time. The controller periodically activates different row groups in a time-multiplexed manner, allowing capacitive loading to be shared across multiple rows simultaneously, which reduces peak current requirements and overall power consumption while maintaining manageable device complexity
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 the creation of larger, higher-resolution passive matrix EL displays with reduced power consumption and minimized luminance artifacts at tile boundaries, achieving combined benefits of tiling and multiline drive methods without introducing visible errors.
Implementation Method 1
each light-emitting element being formed from a light-emitting layer that is sandwiched between an orthogonal array of row and column electrodes
Data Source
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AI summary
A tiled, passive-matrix, EL display, including two or more EL tiles, each EL tile including an array of rows and columns of light-emitting elements, each light-emitting element being formed from a light-emitting layer that is sandwiched between an orthogonal array of row and column electrodes wherein each of the two or more EL tiles further include at least one row driver; at least one column driver for operating in conjunction with each of the at least one row drivers to control the flow of electrons between the row and column electrodes to control the emission of light from each of the light-emitting elements, with a first exception that when the boundary between the two tiles is to be illuminated, then the number of rows of simultaneously illuminated rows of light-emitting elements within one tile is less than the predetermined number.