Dual-LED Pixel Layout for Lower-Power PM Display Refresh
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Solution Overview
Problem
The high refresh rate in passive matrix (PM) driving architectures for sub-millimeter-level light emitting diodes leads to frequent switching between high and low levels of the PWM data control signal, causing excessive power consumption due to parasitic capacitance on the data line.
Innovation Solution
A display panel design that includes a data line driver chip connected to two light emitting diodes in each pixel unit, where one diode is driven in the low level duration of the PWM signal and the other in the high level duration, reducing the frequency of level switching by lighting both diodes in each cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the refresh rate is increased in PM driving architecture, then the display performance is improved, but the power consumption increases due to frequent switching of PWM data control signal
Solution Approach 1:
The pixel unit is segmented into two separate light emitting diodes (first LED and second LED) with different connection configurations. The first LED connects anode to scanning line and cathode to data line, while the second LED connects cathode to scanning line and anode to data line. This segmentation allows independent control of each LED through the same data line, enabling both LEDs to be driven during the same PWM signal cycle without requiring additional switching operations.
Solution Approach 2:
The data line is designed to serve multiple functions by connecting to both the cathode of the first LED and the anode of the second LED. A single PWM data control signal can simultaneously control both LEDs through their respective connections, making the data line universal for driving multiple light emitting elements without requiring separate control lines for each LED type.
2Productivity
If the PWM data control signal switches between high and low levels frequently, then the light emitting diodes can be controlled to turn on and off for high refresh rate, but the parasitic capacitance on the data line causes additional power consumption
Solution Approach 1:
Both the first LED and second LED are driven during the same PWM data control signal cycle, ensuring continuous utilization of the data line and PWM signal. The first LED is driven during the low level duration while the second LED is driven during the high level duration, eliminating idle periods and reducing the need for frequent signal switching between different rows of LEDs.
Solution Approach 2:
The patent employs periodic PWM data control signals with specific timing characteristics. During the low level duration of the PWM signal, the first LED is driven; during the high level duration, the second LED is driven. This periodic action pattern allows both LEDs to be controlled in a rhythmic manner synchronized with the PWM signal, reducing unnecessary switching operations.
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 effectively reduces power consumption by minimizing the frequency of parasitic capacitance charging and discharging, enhancing the display performance on large screens.
Implementation Method 1
each of the pixel units includes: a first light emitting diode and a second light emitting diode
Data Source
AI summary
A display panel includes a data line driver chip and a plurality of pixel units. Each of the pixel units includes: a first light emitting diode and a second light emitting diode. The data line driver chip is connected to a cathode of each of the first light emitting diodes and an anode of each of the second light emitting diodes through a data line. In a same pixel unit, an anode of the first light emitting diode is connected to odd-row scanning lines, the cathode of the first light emitting diode is connected to the anode of the second light emitting diode, and a cathode of the second light emitting diode is connected to even-row scanning lines.