Micro LED Display Pixel Circuit PAM PWM Current Control
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Solution Overview
Problem
Inorganic light emitting element display panels face issues with color reproducibility due to changes in wavelength and intensity of emitted light when driven using pulse amplitude modulation (PAM), leading to suboptimal image gradation and brightness control.
Innovation Solution
A display module with a pixel circuit that employs both pulse amplitude modulation (PAM) and pulse width modulation (PWM) to control the driving current's amplitude and pulse width, respectively, ensuring uniform amplitude and adjustable pulse width for each sub-pixel, thereby stabilizing light emission and improving color reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pulse amplitude modulation (PAM) is used to drive inorganic LEDs, then light intensity control is achieved, but wavelength changes causing color reproducibility deterioration occur
Solution Approach 1:
The patent segments the light control function into two independent dimensions: amplitude control for intensity and pulse width control for duration. By separating these functions, the system achieves intensity modulation without wavelength variation, resolving the color reproducibility issue inherent in PAM alone.
Solution Approach 2:
The patent dynamically adjusts both amplitude and pulse width of driving currents based on image signal characteristics. This dynamic dual-parameter control allows the system to maintain optimal color accuracy across varying brightness levels, overcoming the static wavelength-intensity relationship in conventional PAM driving.
2Productivity
If inorganic LEDs are driven with varying current amplitude, then light gradation is achieved, but image quality deteriorates due to wavelength changes
Solution Approach 1:
The patent changes multiple electrical parameters simultaneously - specifically adjusting both current amplitude and pulse width based on the desired light gradation. This multi-parameter approach enables smooth brightness transitions while maintaining constant wavelength, thereby preserving image quality across all gray levels.
3Use of energy by moving object
If micro LED display panels are used instead of LCD or OLED, then energy efficiency and brightness are improved, but color stability issues persist
Solution Approach 1:
The patent implements feedback mechanisms that monitor both light intensity and color characteristics in real-time. Based on this feedback, the system dynamically adjusts driving current parameters to compensate for any wavelength shifts, ensuring color stability is maintained while leveraging the energy efficiency advantages of micro LED technology.
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 solution enhances color reproducibility and stability of light emission in micro LED display panels by maintaining consistent wavelength and intensity, improving image quality and reducing smudge or color issues, while allowing for high dynamic range and efficient energy use.
Implementation Method 1
a light emitting element (LED) mounted on the glass substrate... inorganic light emitting elements such as a red light emitting diode (LED), a green LED, and a blue LED
Data Source
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AI summary
A display module includes a display panel including an inorganic light emitting element and a pixel circuit configured to provide a driving current to the inorganic light emitting element; and a driver configured to drive the pixel circuit. The pixel circuit includes a pulse amplitude modulation (PAM) circuit configured to control an amplitude of the driving current based on an applied PAM data voltage, and a pulse width modulation (PWM) circuit configured to control a pulse width of the driving current based on an applied PWM data voltage. The driver includes a power supply circuit configured to provide, to the PAM circuit, a first power supply voltage for driving the PAM circuit, and provide, to the PWM circuit, a second power supply voltage for driving the PWM circuit.