Pixel Driving Circuit Gray Scale Control via Pulse Width Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current display panels using pulse amplitude modulation for gray scale presentation suffer from color reproducibility issues due to wavelength and gray scale changes being linked to the amplitude of the driving current, leading to color deviation.
Innovation Solution
A pixel driving circuit with a data writing module, data conversion module, and current driving module that generates current driving control signals with varying pulse widths for different gray-scale states, improving light-emitting duration and thus color reproducibility by decoupling gray scale from current amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pulse amplitude modulation is used to control gray scales, then the driving current amplitude can be adjusted to achieve different gray scales, but the wavelength and gray scale of emitted light change simultaneously causing color deviation
Solution Approach 1:
The patent changes the control parameter from current amplitude to pulse width (duration). By varying the pulse width of a fixed-amplitude driving current, the light-emitting duration changes while the current amplitude remains constant, thus controlling gray scale without affecting wavelength and color reproduction
Solution Approach 2:
The patent employs periodic pulsing of the driving current with different pulse widths within a fixed period. This periodic action allows the light-emitting device to emit light for different durations corresponding to different gray scales, while maintaining constant current amplitude to ensure color accuracy
Data Source
AI summary
A pixel driving circuit and a display panel are provided. The pixel driving circuit includes a data writing module, a data conversion module, and a current driving module. The data writing module is electrically connected to a first node and configured to transmit a data signal to the first node. The data conversion module is electrically connected to the first node, a second node, and a modulation signal source, and configured to generate a current driving control signal, and to output the current driving control signal to the second node. The current driving module is electrically connected to the second node, a light-emitting control wire, and a light-emitting device, and configured to control the light-emitting device to emit light. An effective pulse of the current driving control signal has different pulse widths in different gray-scale states.