Micro-LED Display Driving for Low-Luminance Color Stability
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Solution Overview
Problem
Micro-LED elements used in small display devices experience a decrease in external quantum efficiency (EQE) and color coordinate distortion due to variable current levels, especially when operating in low luminance modes.
Innovation Solution
A display device and driving method that controls micro-LED elements in small display devices by fixing the data voltage in low luminance operation modes and varying the pulse width, and vice versa in high luminance operation modes, to maintain consistent EQE and prevent color distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If micro-LED elements are used in small display devices with relatively low current, then the display device can be made smaller and more portable, but the external quantum efficiency (EQE) is lowered and light-emitting efficiency decreases
Solution Approach 1:
The patent applies dynamics by implementing two distinct driving modes (first driving mode with fixed pulse width and variable data voltage, second driving mode with fixed data voltage and variable pulse width) that can dynamically switch based on luminance requirements. This allows the micro-LED element to operate at optimal current levels for maintaining EQE while enabling small display device implementation
Solution Approach 2:
The patent changes operational parameters by varying either data voltage or pulse width depending on the driving mode, rather than maintaining a fixed low current operation. This parameter variation allows the system to overcome the EQE degradation issue inherent in low-current micro-LED operation while still achieving compact display device size
2Use of energy by moving object
If micro-LED elements operate at low current levels, then power consumption is reduced, but external quantum efficiency (EQE) and light-emitting efficiency are lowered
Solution Approach 1:
The patent implements dynamic operation with two driving modes that can switch based on luminance requirements. The first driving mode optimizes for efficiency at higher currents, while the second driving mode optimizes for power consumption at lower currents, allowing the system to balance power consumption and EQE based on operational needs
Solution Approach 2:
The patent changes the operational parameters (data voltage and pulse width) depending on the driving mode to optimize the balance between power consumption and EQE. By varying these parameters rather than maintaining fixed low current operation, the system achieves efficient power usage without permanent EQE degradation
3Measurement precision
If the data voltage is varied to control luminance, then luminance control precision is improved, but color coordinate distortion occurs when using micro-LED elements at low current
Solution Approach 1:
The patent implements dynamic switching between two driving modes where the second driving mode (fixed data voltage, variable pulse width) specifically addresses color stability by keeping data voltage constant. This prevents the color coordinate distortion that occurs when data voltage is varied at low current levels, while the first driving mode provides precise luminance control when needed
Solution Approach 2:
The patent changes which parameter is varied (data voltage or pulse width) depending on the driving mode and luminance requirements. By selectively fixing the data voltage in the second driving mode, the system maintains color coordinate stability while still achieving luminance control through pulse width modulation
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
The method suppresses EQE degradation and maintains high image quality and reliability in small display devices, enabling high resolution, narrow bezel, and low power consumption.
Implementation Method 1
The micro light-emitting element is a semiconductor light-emitting element that uses property of emitting light when current flows through a semiconductor
Data Source
AI summary
A display device may include a display panel including at least one of a first sub-pixel, a second sub-pixel and a third sub-pixel, and a driver configured to control a light-emission operation of the at least one of the first to third sub-pixels. In addition, the driver may be configured to control the light-emission operation of the at least one of the first to third sub-pixels so that, in a first control mode, a pulse width is fixed and a data voltage value is varied such that the at least one sub-pixel emits light at a first luminance, and, in a second control mode, the data voltage value is fixed, and the pulse width is varied such that the at least one sub-pixel emits light at a second luminance.