OLED Signal Controller Adaptive Light Emitting Periods
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Solution Overview
Problem
Active matrix OLED displays face challenges in optimizing light emitting periods to maintain image quality and luminance, particularly when transitioning between bright and dark frames, due to fixed reset periods that can lead to luminance deterioration.
Innovation Solution
A signal controller adjusts light emitting periods based on image parameters and threshold values, generating driving control signals for short or long periods to adaptively control the light emitting duration, ensuring proper reset and compensation of transistors to maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed reset period is used for all frames, then the transistor reset is simplified and control is easier, but luminance deterioration occurs when transitioning between bright and dark frames
Solution Approach 1:
The patent applies dynamics by making the reset period variable rather than fixed. The signal controller dynamically adjusts the reset period length based on the luminance characteristics of the current and previous frames. When transitioning from a bright frame to a dark frame, a longer reset period is applied to prevent luminance deterioration, while normal reset periods are used during stable display conditions. This dynamic adjustment resolves the contradiction between control simplicity and image quality reliability.
2Illumination intensity
If the light emitting period is extended to improve luminance, then the reset period must be shortened, but this may insufficiently reset the transistor gate voltage
Solution Approach 1:
The patent resolves this contradiction by dynamically adjusting both the light emitting period and reset period based on frame luminance characteristics. When the current frame is dark or the previous frame was bright, the reset period is extended and the light emitting period is相应 reduced to ensure complete transistor reset. When luminance conditions are stable and bright, the reset period is shortened and light emitting period is extended to maximize luminance. This dynamic balance ensures both adequate reset and optimal luminance output.
3Illumination intensity
If the light emitting period is extended to improve luminance, then the frame time for other operations is reduced, but this may affect compensation and scanning time
Solution Approach 1:
The patent applies dynamics by making the light emitting period variable based on luminance conditions rather than using a fixed schedule. The signal controller calculates the appropriate light emitting period duration by considering the luminance of current and previous frames, ensuring that compensation and scanning operations are allocated sufficient time even when luminance is prioritized. This dynamic allocation prevents time loss for critical operations while maximizing luminance output when conditions permit.
4Reliability
If a longer reset period is used to prevent luminance deterioration, then the light emitting period is reduced, but this decreases overall luminance output
Solution Approach 1:
The patent resolves this contradiction through dynamic adjustment of the reset period based on actual luminance conditions. Rather than using a consistently long reset period, the signal controller extends the reset period only when necessary - specifically when transitioning from bright to dark frames or when luminance instability is detected. During stable display conditions or when displaying bright content, the reset period is minimized to maximize light emitting time and overall luminance output. This selective, dynamic approach maintains luminance stability only when required while preserving maximum luminance output during normal operation.
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 adaptive control enhances the luminance and image quality of the display by optimizing light emitting periods, reducing luminance issues associated with fixed reset times.
Implementation Method 1
an organic light emitting diode (OLED) including an anode and a cathode forming an electric field, and an organic light emitting material emitting light by the electric field
Data Source
AI summary
A display device includes a plurality of pixels, a scan driver sequentially applying a scan signal to a plurality of scan lines, a data driver applying a data signal corresponding to the scan signal to a plurality of data lines, and a signal controller calculating an image parameter from an image signal, and generating and transmitting one of a driving control signal for short period light emitting and a driving control signal for long period light emitting to the scan driver and the data driver by using the image parameter. The driving control signal for short period light emitting is a signal controlling a light emitting period in which a plurality of pixels emit light during one frame with a first period. The driving control signal for long period light emitting is a signal controlling the light emitting period with a second period that is longer than the first period.