Shared PAM-PWM Pixel Driving for Uniform High-Resolution Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices face challenges in reducing the number of transistors per sub pixel, which increases design area and can lead to color coordinate distortion and luminance differences among sub pixels.
Innovation Solution
Implementing a display device where multiple sub pixels share a single Pulse Amplitude Modulation (PAM) circuit, combined with Pulse Width Modulation (PWM) circuits, to reduce transistor count and enable individual control of emission timing and gray scale levels, while using external and internal compensation methods to stabilize transistor threshold voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each sub pixel has its own PAM circuit, then the control precision and emission intensity accuracy are improved, but the number of transistors and design area increase
Solution Approach 1:
Multiple sub-pixels share a common PAM circuit instead of each sub-pixel having its own dedicated PAM circuit. This merging approach reduces the number of transistors and design area while maintaining control precision through the PWM circuit's individual control capability.
Solution Approach 2:
The control function is segmented between the shared PAM circuit for amplitude modulation and individual PWM circuits for pulse width control. This allows the PAM circuit to be shared while maintaining precise control over each sub-pixel's emission through the PWM stage.
2Area of stationary object
If the number of transistors is reduced by sharing PAM circuits, then the design area is reduced, but the control capability over emission timing may be compromised
Solution Approach 1:
The system dynamically switches between PAM and PWM control modes. The PAM circuit provides amplitude control when needed, while the PWM circuit handles timing and pulse width control, allowing the shared architecture to maintain full control capability through coordinated operation of both circuit types.
Solution Approach 2:
The PWM circuit acts as an intermediary between the shared PAM circuit and the individual sub-pixels. It receives the amplitude-modulated signal from the PAM circuit and further modulates it with precise timing control, ensuring that sharing the PAM circuit does not compromise emission timing control.
3Ease of manufacture
If transistors are minimized through circuit sharing, then manufacturing cost is reduced, but color coordinate distortion in low current band may increase
Solution Approach 1:
The system incorporates feedback mechanisms where the PWM circuit monitors and adjusts the emission characteristics of each sub-pixel individually. This feedback control compensates for potential color coordinate distortion that may arise from the shared PAM circuit, especially in low current bands where LED characteristics vary more significantly.
Data Source
AI summary
According to an aspect of the present disclosure, a display device includes a display panel in which a plurality of pixel groups is defined; one PAM circuit disposed in each of the plurality of pixel groups; a plurality of PWM circuits which is disposed in each of the plurality of pixel groups and is connected to one PAM circuit; a plurality of light emitting diodes which is disposed in each of the plurality of pixel groups and is connected to the plurality of PWM circuits. The plurality of PWM circuits is connected to an output terminal of one PAM circuit in parallel in each of the plurality of pixel groups. Accordingly, the plurality of PWM circuits shares one PAM circuit to reduce the number of overall transistors and simplify the structure of the display device.