Micro LED Display Driving Circuit with Digital PWM Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current display devices using OLEDs face challenges with emission lifetime and sticking at high luminance, necessitating the development of alternative self-luminous elements like micro LEDs, which require effective driving methods to achieve high luminance, wide viewing angles, high contrast, and low power consumption.
Innovation Solution
The image display device incorporates a glass substrate with driving circuits and light-emitting elements arranged in a matrix configuration, utilizing pulse amplitude and pulse width modulation to control the driving current, enabling efficient light emission and luminance control through analog and digital PWM techniques, and incorporating inorganic semiconductor light-emitting elements to reduce sticking and improve color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If OLED is used as self-luminous element, then high luminance and wide viewing angle are achieved, but emission lifetime is reduced and sticking occurs at high luminance
Solution Approach 1:
The patent applies parameter changes by switching from analog PWM to digital PWM with multiple bit depths (10-bit, 12-bit, 14-bit) to control luminance. This digital approach with increased bit depth provides finer luminance control resolution, enabling high luminance display while reducing the duty cycle requirements that cause OLED sticking and degradation, thereby extending emission lifetime.
2Reliability
If micro LED is used as self-luminous element, then emission lifetime and sticking issues are improved, but driving control complexity increases
Solution Approach 1:
The patent segments the luminance control into multiple digital bit depths (10-bit, 12-bit, 14-bit) that can be independently selected and combined. This segmentation allows the system to achieve fine luminance control through digital means without requiring complex analog circuitry, simplifying the overall driving control while maintaining high reliability of micro LEDs.
Solution Approach 2:
The patent replaces analog PWM control with digital PWM control, substituting continuous analog voltage control with discrete digital signal control. This substitution simplifies the driving control architecture by using standard digital logic circuits and eliminates the need for complex analog timing circuits, while providing more precise and stable luminance control for micro LED elements.
3Ease of operation
If analog PWM is used for driving, then simple control is achieved, but power consumption and luminance control precision are insufficient
Solution Approach 1:
The patent changes the control parameter from analog voltage levels to digital bit depth parameters. By using 10-bit, 12-bit, or 14-bit digital PWM, the system achieves 1024, 4096, or 16384 discrete luminance levels respectively. This parameter change maintains ease of operation through digital control while dramatically improving luminance control precision and reducing power consumption through optimized duty cycles.
4Illumination intensity
If high luminance is achieved with OLED, then display brightness is improved, but sticking and reduced emission lifetime occur
Solution Approach 1:
The patent adopts micro LED elements which have significantly longer operational lifetimes and do not suffer from sticking issues compared to OLED. By replacing the short-lived OLED technology with long-lived micro LED technology, the system achieves high luminance without the harmful sticking effect, effectively treating the light-emitting element as a more durable replacement.
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 configuration enhances the display's ability to achieve high dynamic range and low power consumption, improving gradation capabilities beyond conventional methods and reducing sticking issues at high luminance, while maintaining low power consumption and high dynamic range.
Implementation Method 1
A display that uses organic EL (electroluminescence (OLED)) as a self-luminous element for the display device
Data Source
AI summary
An image display device includes a plurality of driving circuits disposed on a substrate, and a plurality of light emitting elements corresponding to a plurality of pixels respectively. Each of the plurality of driving circuits being configured to provide a driving current to each of the plurality of light emitting elements and to control the driving current by a pulse amplitude modulation and a pulse width modulation. The driving circuit being configured using TFTs.