Self-luminous Display Device with Light Emission Interruption for Brightness Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Self-luminous display devices using organic electro-luminescence elements suffer from a 'flashing phenomenon' due to variations in transistor characteristics, leading to instantaneous changes in screen brightness during transitions between different screen displays.
Innovation Solution
The implementation of a drive circuit that applies a light emission enabling bias to a light-emitting diode and includes a light emission interruption period, where the bias is temporarily changed to a non-light emission bias, and a light emission disabling process that reverse-biases the diode, ensuring constant reverse bias application time for accurate threshold voltage and mobility corrections, thereby controlling the light emission enabled period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the light-emitting diode is reverse-biased for threshold voltage and mobility corrections, then the uniformity of drive current is improved, but the brightness across the screen undergoes instantaneous change (flashing phenomenon)
Solution Approach 1:
The patent applies preliminary correction actions (threshold voltage and mobility corrections) during periods when the light-emitting diode is not emitting light. By performing these corrections in advance during dedicated correction periods, the system improves drive current uniformity without causing visible flashing to the user during normal display operation.
Solution Approach 2:
The patent implements periodic correction cycles where the light-emitting diode alternates between emission periods and correction periods. During correction periods, the diode is reverse-biased to perform threshold voltage and mobility corrections, while during emission periods, normal display operation occurs. This periodic structure allows corrections to be applied systematically without continuous flashing.
2Adaptability or versatility
If the drive transistor controls current according to data potential, then the light emission brightness is adjusted, but the characteristic variation of the drive transistor directly affects brightness uniformity
Solution Approach 1:
The patent implements feedback mechanisms where the drive circuit monitors and measures the actual drive current and brightness output, then uses this information to adjust correction parameters. By measuring the relationship between gate-to-source voltage and drive current, the system calculates mobility values and applies appropriate corrections to compensate for transistor characteristic variations, thereby improving brightness uniformity across the screen.
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 approach effectively prevents or suppresses the flashing phenomenon by maintaining constant light emission intensity across the screen, improving brightness uniformity and correcting for transistor characteristic variations.
Implementation Method 1
a light-emitting diode adapted to emit light when applied with a bias voltage
Implementation Method 2
a holding capacitor coupled to a control node of the drive transistor
Data Source
AI summary
A self-luminous display device includes: pixel circuits; and a drive circuit, wherein each of the pixel circuits includes a light-emitting diode, a drive transistor connected to a drive current channel of the light-emitting diode, and a holding capacitor coupled to a control node of the drive transistor, the drive circuit applies a light emission enabling bias to the light-emitting diode after correcting the drive transistor and writing a data voltage to the control node, provides, during a light emission enabled period in which the light emission enabling bias is applied, a light emission interruption period adapted to change the light emission enabling bias to a non-light emission bias with the data voltage held by the holding capacitor, and performs a light emission disabling process, adapted to reverse-bias the light-emitting diode to stop the light emission, for a constant period after the light emission enabled period.