Light-Emitting Device Inclined Gate-Control Waveforms for Uniform Luminance
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Solution Overview
Problem
Existing display devices with organic light-emitting elements face challenges in achieving uniform luminance across a screen due to variations in device characteristics, particularly as screen size and pixel count increase, and existing solutions only address the mobility of drive transistors without considering other transistors.
Innovation Solution
A light-emitting device with inclined waveforms for control signals of both write and light emission control transistors, using resistor elements and adjusted transistor resistances to reduce variations in signal propagation, ensuring uniform light emission by minimizing differences in threshold correction periods across the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the screen size and number of pixels are increased, then the display resolution and coverage are improved, but uniformity in luminance across the screen deteriorates due to variations in device characteristics
Solution Approach 1:
The patent applies local quality by making the control signal waveform inclination specific to each transistor's position and characteristics. Different transistors receive differently inclined waveforms tailored to their individual threshold voltages and mobility characteristics, thereby compensating for local variations across the screen and maintaining luminance uniformity even as screen size and pixel count increase
2Manufacturing precision
If only the drive transistor mobility is corrected through waveform inclination, then the drive transistor performance is improved, but other transistors in the pixel circuit remain unoptimized causing residual luminance variations
Solution Approach 1:
The patent implements universality by extending the waveform inclination technique to all transistors in the pixel circuit (drive transistor, sampling transistor, light emission control transistor, and write transistor). This multi-functional approach ensures that every transistor's characteristics are optimized, not just the drive transistor, thereby achieving comprehensive correction of luminance variations across the display
3Device complexity
If standard control signals are used without waveform inclination, then the circuit operation is simple, but variations in threshold correction periods cause luminance shading across the screen
Solution Approach 1:
The patent applies parameter changes by modifying the waveform parameters (inclination slope, timing) of control signals based on transistor characteristics. By changing these parameters dynamically for different transistors, the patent equalizes threshold correction periods across the screen, preventing luminance shading while maintaining manageable circuit complexity through systematic waveform generation
Data Source
AI summary
A light-emitting device includes a plurality of light-emitting elements and a plurality of pixel circuits. The plurality of pixel circuits each includes a drive transistor configured to drive a corresponding one of the plurality of light-emitting elements, a write transistor configured to write a signal to a gate of the drive transistor, and a light emission control transistor configured to control connection between the gate of the drive transistor and a power supply. The light-emitting device includes a first control line for controlling the write transistor, a second control line for controlling the light emission control transistor, a first circuit configured to incline a signal waveform of the first control line, and a second circuit configured to incline a signal waveform of the second control line.