Pixel Circuit Brightness Consistency via Local Voltage
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Solution Overview
Problem
Micro LEDs in display devices emit light of different colors with varying luminous efficiencies, affecting the display effect due to differences in brightness among sub-pixels.
Innovation Solution
A pixel circuit design comprising a first switching sub-circuit, a gray scale control sub-circuit, and a driving sub-circuit, where the second switching sub-circuit provides a constant voltage to ensure the light-emitting element operates at its highest luminous efficiency, and the array substrate is driven by distinct scanning signals to adjust the light-emitting time of sub-pixels, compensating for differences in luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If micro LEDs emit light of different colors, then the display device can achieve full-color display, but the luminous efficiencies of different colored micro LEDs differ, causing inconsistent brightness among sub-pixels
Solution Approach 1:
The patent applies local quality by providing different operating voltages to different colored sub-pixels through separate voltage terminals. Specifically, red sub-pixels receive a first voltage while green and blue sub-pixels receive a second voltage, allowing each color to operate at its optimal luminous efficiency point. This localized voltage adjustment compensates for the inherent luminous efficiency differences among different colored micro LEDs, achieving consistent brightness across all sub-pixels.
2Device complexity
If a constant voltage is applied to all light-emitting elements, then the circuit design is simplified, but the luminous efficiency cannot be optimized for different colored micro LEDs
Solution Approach 1:
The patent implements local quality by creating distinct voltage supply paths for different colored sub-pixels. The circuit includes a first voltage terminal connected to red sub-pixels and a second voltage terminal connected to green and blue sub-pixels. This localized voltage optimization allows each color to operate at its peak luminous efficiency without significantly increasing overall circuit complexity, as the voltage selection is determined during the selection phase based on the color of the sub-pixel being activated.
3Illumination intensity
If the light-emitting time of sub-pixels is extended to compensate for lower luminous efficiency, then brightness consistency is improved, but the scanning time and frame rate are affected
Solution Approach 1:
The patent applies parameter changes by adjusting the operating voltage parameter for different colored sub-pixels rather than changing the time parameter. By providing optimized voltages (first voltage for red, second voltage for green and blue), the patent enables different colored micro LEDs to achieve comparable luminous efficiency within the same scanning cycle. This voltage-based compensation eliminates the need to extend light-emitting times for lower efficiency sub-pixels, thereby maintaining the normal scanning rate and frame rate while achieving brightness consistency.
Data Source
AI summary
An array substrate including a plurality of pixel units arranged in a matrix is provided. Each pixel unit at least includes a first sub-pixel, a second sub-pixel and a third sub-pixel that emit light of different colors, the first sub-pixel has a lower luminous efficiency than the second and third sub-pixels. The array substrate further comprises a plurality of first gate lines and a plurality of second gate lines that correspond to respective rows of pixel units of the plurality of pixel units. The first sub-pixel in each row of pixel units of the plurality of pixel units is coupled to a first gate line of the plurality of first gate lines, and the second sub-pixel and the third sub-pixel in the row of pixel units of the plurality of pixel units are both coupled to a second gate line of the plurality of second gate lines.