LED Display PWM Segmentation for Small-Pitch Thermal Control
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Solution Overview
Problem
Conventional LED displays face challenges in achieving small pixel pitches while managing complexity and cost, particularly in high-resolution displays, due to densely populated driver electronics and thermal crowding.
Innovation Solution
Implementing active electrical elements in LED packages that allow for pulse width modulation (PWM) with segmented duty cycles, enabling multiple activations and deactivations within a PWM period, and incorporating active circuitry for enhanced control and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If driver electronics are densely populated to achieve high resolution displays, then pixel pitch is reduced, but thermal crowding and device complexity increase
Solution Approach 1:
The patent segments the driver electronics functionality by integrating active electrical elements directly into individual LED packages rather than using densely populated separate driver components. Each LED package includes its own active electrical element that can independently control multiple LED chips, dividing the control function from centralized drivers to distributed package-level controllers. This segmentation reduces thermal crowding by spreading heat generation across more distributed, smaller heat sources rather than concentrated driver electronics.
Solution Approach 2:
The patent implements nesting by placing active electrical elements inside LED packages, which themselves contain LED chips. This nested structure integrates the control functionality within the existing package footprint, eliminating the need for separate driver components on the circuit board. The active electrical element is nested within the LED package structure, allowing high-resolution displays to be achieved without increasing overall device complexity or thermal crowding.
2Length of moving object
If driver electronics are densely populated to achieve high resolution displays, then pixel pitch is reduced, but device complexity increases
Solution Approach 1:
The patent merges the LED chip and active electrical element into a single integrated LED package structure. Instead of having separate LED components and separate driver electronics on the circuit board, the control functionality is combined with the LED chip at the package level. This merging reduces device complexity by eliminating numerous separate driver components, decoders, and control circuits that would otherwise be required to achieve high-resolution displays.
Solution Approach 2:
The active electrical element integrated into each LED package serves multiple functions: it acts as a driver for controlling LED chip activation, provides pulse width modulation capability for brightness control, and enables segmented duty cycle operation for thermal management. This multi-functionality within a single integrated component reduces overall device complexity compared to using separate specialized components for each function.
3Temperature
If PWM duty cycle is segmented to allow multiple activations within a period, then thermal management is improved, but control complexity increases
Solution Approach 1:
The active electrical element integrated into the LED package autonomously generates the segmented PWM duty cycle signals without requiring external control circuitry. The active electrical element itself performs the function of segmenting the duty cycle to control thermal management, making the system self-sufficient. This self-service capability reduces control complexity by eliminating the need for separate PWM generation circuits or complex external control logic.
Solution Approach 2:
The active electrical element is pre-configured within the LED package to automatically implement segmented duty cycle operation. The segmentation logic is built into the active electrical element, allowing it to preemptively manage thermal conditions by dividing the activation period into multiple shorter pulses. This preliminary integration of the segmentation capability simplifies control by having the functionality built-in rather than requiring runtime configuration or complex external control.
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 approach reduces thermal crowding and complexity, enabling higher resolution displays with smaller pixel pitches by allowing continuous operation of LED pixels without continuous pulsing, thus improving efficiency and reducing costs.
Implementation Method 1
Light emitting diodes (LEDs) are solid-state devices that convert electrical energy to light and generally include one or more active layers of semiconductor material (or an active region) arranged between oppositely doped n-type and p-type layers. When a bias is applied across the doped layers, holes and electrons are injected into the one or more active layers where they recombine to generate emissions such as visible light or ultraviolet emissions.
Data Source
AI summary
Active control of LEDs, LED packages, and related LED displays by way of pulse wide modulation (PWM) is disclosed. Effective PWM frequencies for LEDs are increased by segmenting duty cycles in which LEDs are electrically activated within individual PWM periods. Segmented duty cycles may be provided by transforming or re-ordering a sequence in which control signals are provided to LEDs. As such, LEDs may be electrically activated and deactivated multiple times within each PWM period. Active electrical elements that are incorporated into one or more LED packages of an LED display may be capable of segmenting the duty cycle within each LED package. Active electrical elements may also be capable of receiving reset signals from a data stream to either initiate a reset action or pass the reset signals along to other active electrical elements of a display.