Active Mini LED Pixel Driving for Brightness Uniformity
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Solution Overview
Problem
Mini LED displays face issues of non-uniformity and image sticking due to variations in threshold voltage and mobility of low-temperature polysilicon and oxide thin-film transistors, leading to brightness differences and luminance degradation, which existing technologies struggle to adequately address.
Innovation Solution
An active mini LED display using metal oxide field effect transistors in each pixel, where the gate voltage is controlled to modulate current and brightness, with separate driver circuits for channel and scanning signals to improve heat dissipation and reduce wiring complexity, and employing a heterogeneous polycrystalline wafer level packaging method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low temperature polysilicon thin film transistors are used in mini LED displays, then mobility and stability are improved, but non-uniformity in electrical parameters (threshold voltage and mobility) occurs at different positions on large-area glass substrates, causing brightness differences and mura phenomenon
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual threshold voltage of each transistor and using this information to adjust the driving voltage dynamically. This compensates for the non-uniformity in transistor characteristics, ensuring consistent display brightness across the entire panel despite variations in electrical parameters
Solution Approach 2:
The patent dynamically adjusts the driving voltage parameter based on the measured threshold voltage of each transistor. By changing the voltage parameter in real-time, the system compensates for transistor non-uniformity and maintains consistent display performance across different positions on the large-area substrate
2Manufacturing precision
If oxide thin film transistors are used in mini LED displays, then uniformity of electrical parameters is improved, but threshold voltage drift occurs under long-term pressure and high temperature, causing image sticking phenomenon
Solution Approach 1:
The patent performs preliminary measurement of each transistor's threshold voltage before the display is put into operation. This advance measurement allows the system to pre-calculate compensation values that will counteract threshold voltage drift under long-term pressure and high temperature conditions, preventing image sticking before it occurs
Solution Approach 2:
The patent incorporates a feedback mechanism that continuously monitors and adjusts for threshold voltage drift. By using the pre-measured threshold voltage data and adjusting driving parameters accordingly, the system compensates for drift under long-term pressure and high temperature, preventing image sticking
3Illumination intensity
If organic light emitting diodes are used in mini LED displays, then high contrast and ultra-thin characteristics are achieved, but luminance degradation occurs as lighting time increases
Solution Approach 1:
The patent implements a feedback mechanism that measures the actual threshold voltage of each transistor and uses this information to adjust the driving voltage dynamically. This compensates for OLED luminance degradation over time, maintaining consistent display brightness despite aging effects
Solution Approach 2:
The patent dynamically adjusts the driving voltage parameter based on measured transistor characteristics and OLED aging trends. By changing the voltage parameter in real-time, the system compensates for luminance degradation and maintains consistent display performance over extended operation periods
4Power
If mini LED technology is used to transfer tiny light emitting diodes to the display, then low power consumption and high brightness are achieved, but contour patterns with different luminous brightness and wavelength are produced during epitaxy manufacturing, causing mura on the display
Solution Approach 1:
The patent implements a feedback mechanism that measures the actual characteristics of each mini LED and uses this information to adjust the driving voltage. This compensates for the contour patterns and brightness variations produced during epitaxy manufacturing, ensuring uniform display appearance despite manufacturing non-uniformities
Solution Approach 2:
The patent dynamically adjusts the driving voltage parameter based on the measured characteristics of each mini LED. By changing the voltage parameter, the system compensates for the different luminous brightness and wavelength variations produced during epitaxy manufacturing, eliminating mura effects
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 solution enhances the uniformity and stability of mini LED displays, reducing image sticking and luminance degradation, while improving heat dissipation and display reliability by minimizing the distance between power supply and grounding lines and dispersing control transistors within each pixel.
Implementation Method 1
The gate voltage of the metal oxide field effect transistor connected in series in each pixel can be controlled by using the voltage to modulate the current and luminescent brightness required to drive the light emitting diode
Implementation Method 2
each pixel having at least one red mini light emitting diode chip, at least one green mini light emitting diode chip, and at least one blue mini light emitting diode chip
Data Source
AI summary
The present invention provides an active mini LED display and driving method thereof. The driving method comprises: controlling a gate voltage of the metal oxide field effect transistor by a voltage to modulate the current and luminous brightness required to driver the light emitting diode; processing display data to generate timing-controlled channel signals and scanning signals to driver transistors and light emitting diodes to achieve image display; modulating scanning voltage signals or channel voltage signals into analog-type voltages and/or pulse-width-type voltages, and then compensating the unevenness in brightness produced by the epitaxy of each light-emitting diode. The driving method of the active mini LED display of the present invention can reduce the power loss of transmission, and can integrate with various light emitting diodes within a small pixel pitch to manufacture various displays by means of heterogeneous polycrystalline wafer-level packaging.