Luminance Control for Self-Luminescent Pixels
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Solution Overview
Problem
Current display units with current-driven optical elements face challenges in maintaining luminance while reducing electric power consumption, as decreasing current can lead to adverse effects on display quality.
Innovation Solution
A luminance controlling unit and method that dynamically control the duty ratio of a voltage pulse and the potential difference between two voltages, based on an image signal, to manage light emission and extinction in current-driven self-luminescent elements, using a controller to adjust the output from adjacent voltage sources to optimize power usage without significantly reducing luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the magnitude of current is reduced to suppress electric power consumption increase, then power consumption is suppressed, but luminance of the display unit decreases
Solution Approach 1:
The patent applies periodic action by using pulse-width modulation (PWM) to drive the self-luminescent elements. Instead of continuously supplying current, voltage pulses are applied periodically with varying duty ratios. This allows the elements to emit light in pulses rather than continuously, reducing average power consumption while maintaining peak luminance when needed. The periodic nature of the voltage application enables precise control over both power consumption and perceived brightness through human eye integration.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting multiple parameters including voltage amplitude, pulse width (duty ratio), and frequency of the driving signals. By changing these parameters based on display requirements, the system can optimize the balance between power consumption and luminance output. The ability to independently control voltage level and pulse duration provides flexible adjustment to achieve desired display quality at reduced power levels.
2Use of energy by moving object
If the magnitude of current is reduced to suppress electric power consumption increase, then power consumption is suppressed, but display quality deteriorates
Solution Approach 1:
The periodic pulse driving method maintains display quality by utilizing the persistence of vision effect. Although current is reduced and applied intermittently, the rapid pulsing at appropriate frequencies ensures continuous perceived illumination, preventing flicker and maintaining image quality. The periodic action allows the display to refresh images multiple times per frame, preserving visual fidelity even at lower average current levels.
Solution Approach 2:
The patent incorporates feedback mechanisms to monitor and adjust driving parameters in real-time. By detecting actual luminance output and power consumption levels, the system can dynamically optimize the pulse width, voltage amplitude, and timing to maintain display quality standards while minimizing power usage. Feedback ensures that quality thresholds are met even as operating conditions change.
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 suppresses power consumption increases while preventing luminance decreases, maintaining display quality by dynamically controlling voltage and duty ratio within specific ranges.
Implementation Method 1
a current-driven self-luminescent element
Data Source
AI summary
A luminance controlling unit includes a luminance controller that controls luminance of a pixel array including pixels each including a current-driven self-luminescent element. The luminance controller performs, on the basis of an image signal, a dynamic control of a duty ratio of a voltage pulse and a potential difference between a first voltage and a second voltage. The first voltage is outputted from a first voltage source adjacent to an anode of the corresponding self-luminescent element, and the second voltage is outputted from a second voltage source adjacent to a cathode of the corresponding self-luminescent element. The duty ratio is directed to controlling of light emission and light extinction of the self-luminescent element.