LED Pixel Driving IC Active Matrix PWM Ghosting Reduction
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Solution Overview
Problem
Existing light emitting device packages using passive matrix schemes suffer from issues like ghosting and flicker due to incomplete frame interval driving, which affects luminous efficiency and emission quality.
Innovation Solution
A light emitting device package incorporating a pixel driving integrated circuit that employs an active matrix scheme and pulse width modulation, where each light emitting diode chip is driven throughout an entire frame interval, reducing ghosting and flicker by ensuring consistent light emission based on previous frame data and incorporating a demultiplexer, constant current generator, and pulse width modulation data generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive matrix scheme is used to drive light emitting diode chips, then device complexity is reduced, but ghosting and flicker occur due to incomplete frame interval driving
Solution Approach 1:
The pixel driving integrated circuit is segmented into multiple functional modules: demultiplexer for data routing, storage for frame data retention, constant current generator for stable current provision, and pulse width modulation data generator for precise timing control. This segmentation enables complete frame interval driving while maintaining manageable complexity through modular design.
Solution Approach 2:
Frame data is stored in advance in the storage module before being applied to the light emitting diode chips. This preliminary action ensures that complete frame interval driving is achieved, eliminating ghosting and flicker effects that occur when driving is incomplete in passive matrix schemes.
2Reliability
If active matrix scheme with pulse width modulation is used to drive light emitting diode chips, then emission quality is improved by reducing ghosting and flicker, but device complexity increases
Solution Approach 1:
The demultiplexer, storage, constant current generator, and pulse width modulation data generator are merged into a single integrated circuit module positioned under the light emitting diode chips. This merging reduces overall device complexity by consolidating multiple functions into one unit while maintaining the benefits of active matrix driving.
Solution Approach 2:
The pixel driving integrated circuit autonomously generates all necessary signals and currents for driving the light emitting diode chips. The constant current generator automatically provides stable current, the pulse width modulation data generator self-regulates timing, and the storage module automatically retains frame data, eliminating the need for external control circuits and reducing overall system complexity.
3Productivity
If light emitting diode chips are driven throughout entire frame interval, then luminous efficiency is enhanced and ghosting is reduced, but energy consumption increases
Solution Approach 1:
The pulse width modulation data generator applies driving currents in periodic pulses throughout the entire frame interval rather than continuous current. By controlling the duty cycle of these periodic pulses, the system achieves complete frame interval driving for high luminous efficiency while managing energy consumption through pulsed operation rather than continuous current flow.
Solution Approach 2:
The constant current generator dynamically adjusts current parameters based on frame data requirements, and the pulse width modulation data generator varies pulse width and timing parameters to optimize luminous efficiency. By changing current magnitude and pulse duration parameters, the system achieves high productivity when needed while reducing energy consumption during lower demand periods.
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
This solution effectively reduces ghosting and flicker, enhances luminous efficiency, and maintains emission quality by ensuring each light emitting diode chip is driven consistently throughout the frame interval, improving grayscale representation and overall display performance.
Implementation Method 1
first light emitting diode chips each of which emits light
Data Source
AI summary
A light emitting device package includes a first light emitting diode pixel, the first light emitting diode pixel including first light emitting diode chips that each emit light, and a first pixel driving integrated circuit under the first light emitting diode chips of the first light emitting diode pixel, the first pixel driving integrated circuit configured to drive the first light emitting diode chips based on an active matrix scheme, in which each of the first light emitting diode chips is driven using an entire one frame interval, and based on a pulse width modulation scheme, in which a time during which each of first driving currents is applied to a respective one of the first light emitting diode chips is controlled within the entire one frame interval.