Micro LED Display Subpixel Circuit Segmentation for Color Shift
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Solution Overview
Problem
Conventional micro LED display devices face issues with color shift due to wavelength changes under different current densities when using Pulse-Amplitude Modulation (PAM) technology and have short charging times and IR drop problems when using Pulse-Width Modulation (PWM) technology, especially in high-resolution displays.
Innovation Solution
The micro LED display device features independently configured subpixel circuits, with one subpixel circuit using PWM and the other using PAM, allowing for separate control of light-emitting elements to mitigate color shift and power issues, employing a data driving circuit that transmits PWM signals to one subpixel circuit and PAM signals to another.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If PAM technology is used to control micro LEDs, then the display device can operate with simpler circuitry, but wavelength shift occurs under different current densities causing serious color shift
Solution Approach 1:
The display device segments the pixel circuits into two independent types: first pixel circuits using PWM control and second pixel circuits using PAM control. This segmentation allows different control strategies to be applied to different subpixels, resolving the contradiction by enabling PAM to be used only where appropriate while maintaining color accuracy through PWM for other subpixels.
Solution Approach 2:
Different control methods (PWM vs PAM) are applied locally to different subpixels based on their specific requirements. The first subpixel uses PWM for precise color control, while the second subpixel uses PAM for simplified control, optimizing both color accuracy and circuit simplicity in their respective locations.
2Measurement precision
If PWM technology is used to control micro LEDs, then precise control is achieved, but short charging time and IR drop occur in high-resolution displays
Solution Approach 1:
The pixel circuit is segmented into two independent subpixel circuits with different control methods. The PAM-controlled subpixel handles tasks where high precision is less critical, reducing the overall charging time requirement, while the PWM-controlled subpixel maintains precision where needed.
Solution Approach 2:
The control method parameter is changed from uniform PWM across all subpixels to a hybrid approach using both PWM and PAM. This parameter change allows the system to optimize charging time by using PAM for subpixels where precise timing control is less critical.
3Ease of manufacture
If all pixels use the same circuit configuration and control method, then manufacturing is simplified, but color shift and performance issues cannot be effectively addressed
Solution Approach 1:
The display device segments pixels into two types (first pixels and second pixels) with different circuit configurations and control methods. This segmentation maintains manufacturing simplicity through standardized circuit blocks while improving reliability by optimizing control methods for different subpixel requirements.
Solution Approach 2:
Different control qualities (PWM for high precision, PAM for simplified control) are applied locally to different subpixels. This allows the system to achieve high display performance and color accuracy where needed while maintaining ease of manufacture through standardized circuit designs.
Data Source
AI summary
Micro LED display device and driving method thereof. The display device includes a display substrate and a data driving circuit. The display substrate includes multiple pixels, and each pixel includes a first subpixel and a second subpixel. The first subpixel has a first subpixel circuit and a first light-emitting element. The second subpixel has a second subpixel circuit and a second light-emitting element. The first subpixel circuit and the second subpixel circuit are configured independently. The data driving circuit is electrically connected to the first and the second subpixel circuits. The data driving circuit transmits a first data signal to the first subpixel circuits to drive the first light-emitting elements and a second data signal to the second subpixel circuits to drive the second light-emitting elements. The first data signal is a PWM signal, and the second data signal is a PAM signal.