OLED Control Circuit Timing Segmentation for Display Uniformity
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Solution Overview
Problem
Existing electrooptical devices face challenges in improving display quality due to potential variations in power supply caused by the light-emitting or non-light-emitting states of OLEDs, leading to display unevenness and flickering, especially in large display areas where many control transistors switch simultaneously.
Innovation Solution
An electrooptical device with a control circuit that manages the light-emitting and non-light-emitting states of OLEDs by controlling the ratio of light-emitting and non-light-emitting times during horizontal scanning periods, ensuring that OLEDs transition between states only during transition periods and not during data writing, and adjusting the switching times for groups of pixels to distribute potential variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the light emitting element is controlled to emit or not emit light during the horizontal scanning period to adjust average brightness, then the average brightness can be adjusted, but potential variation of power supply occurs affecting data writing accuracy
Solution Approach 1:
The horizontal scanning period is divided into two distinct segments: the operation period for data writing and the transition period for brightness adjustment. By segmenting the time period, the patent allows data writing to complete accurately before brightness control operations begin, preventing power supply variation from affecting data writing accuracy.
Solution Approach 2:
The patent performs data writing operations during the operation period before initiating brightness adjustment in the transition period. This preliminary completion of data writing ensures that voltage deviations caused by light emitting element state changes do not interfere with the data writing process.
2Ease of operation
If control transistors are switched to conduction state simultaneously during horizontal scanning, then brightness control is achieved, but large potential variation of power supply occurs causing display unevenness
Solution Approach 1:
The patent segments the brightness control operation into two phases: during the operation period, control transistors are held in a stable state to maintain power supply potential stability for accurate data writing; during the transition period, control transistors are switched to achieve brightness adjustment. This segmentation prevents simultaneous switching from causing large potential variations.
Solution Approach 2:
The patent establishes a stable control transistor state before the data writing operation begins. By preliminarily stabilizing the control transistor state during the operation period, the patent prevents power supply potential variation from affecting data writing, and only changes the state during the transition period when data writing is complete.
3Adaptability or versatility
If the light emitting element transitions between light-emitting and non-light-emitting states during data writing, then brightness adjustment is possible, but data voltage deviation occurs causing display unevenness
Solution Approach 1:
The patent segments the horizontal scanning period to separate data writing operations from brightness adjustment operations. Data writing occurs during the operation period when the light emitting element maintains a stable state, while brightness adjustment occurs during the transition period when state changes are permitted. This segmentation prevents data voltage deviation.
Solution Approach 2:
The patent completes data writing operations before initiating brightness adjustment. By preliminarily finishing data writing during the operation period, the patent ensures that any subsequent state transitions of the light emitting element during the transition period cannot affect data voltage accuracy.
Data Source
AI summary
An electrooptical device includes a plurality of pixels that are disposed corresponding to each of intersection positions at which a plurality of scanning lines and a plurality of data lines intersect with each other, and each of which includes a light emitting element which emits light by a driving current; and a control circuit that performs a control such that the light emitting element emits light or does not emit light. The control circuit causes the light emitting element to transition between a light-emitting state and a non-light-emitting state, in a transition period, in a case where the light emitting element of each pixel corresponding to the unselected scanning line is to transition between a light-emitting state and a non-light-emitting state.