OLED Array Substrate Alternating Drive Circuit
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Solution Overview
Problem
Existing OLED displays face significant aging issues due to unidirectional hole and electron injection, leading to increased threshold voltage, reduced luminescence brightness, and energy efficiency, which existing DC drive technologies fail to address effectively.
Innovation Solution
The array substrate incorporates a touch driving circuit with scanning and driving transistors, a storage capacitor, and an organic light-emitting diode, utilizing a pulse signal with alternating phases and amplitudes to alternate the emission of adjacent OLEDs in adjacent frame cycles, thereby reducing aging and improving charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If DC drive technology is used for OLED, then the circuit structure is simple and easy to manufacture, but the threshold voltage increases continuously and luminescence brightness reduces due to carrier accumulation
Solution Approach 1:
The patent applies periodic action by implementing alternating drive modes where adjacent pixel units switch between emitting and non-emitting states in successive frame cycles. This periodic switching prevents continuous carrier injection into the OLED, allowing carriers to recombine during non-emitting cycles and thus preventing the threshold voltage increase and luminescence degradation that occur with continuous DC drive.
2Device complexity
If unidirectional hole and electron injection is used in OLED, then the device structure is simple, but carrier accumulation at interfaces forms built-in electric field causing aging
Solution Approach 1:
The patent implements periodic action through alternating drive cycles where pixel units switch between active and inactive states. During inactive cycles, the unidirectional injection is temporarily stopped, allowing accumulated carriers to recombine and preventing continuous buildup at interfaces. This periodic interruption maintains device simplicity while extending OLED lifetime by preventing aging from carrier accumulation.
Solution Approach 2:
The patent applies segmentation by dividing the display into multiple pixel units that operate independently in alternating cycles. This segmentation allows different regions to be in different drive states simultaneously, with some pixels emitting while others are resting and recombining carriers. This spatial-temporal segmentation solves the aging problem without requiring complex modifications to individual OLED structures.
3Duration of action of stationary object
If alternating emission of adjacent OLEDs is implemented, then OLED lifetime is extended and aging is reduced, but the driving circuit becomes more complex
Solution Approach 1:
The patent merges the touch sensing function with the display function by using the same pixel units for both purposes. During non-emitting frame cycles, pixel units serve as touch sensing elements, eliminating the need for separate touch sensing circuits. This merging approach extends OLED lifetime through alternating drive while avoiding additional circuit complexity from dedicated touch sensors.
Solution Approach 2:
The patent implements multi-functionality by enabling pixel units to serve dual purposes: display function during emitting cycles and touch sensing function during non-emitting cycles. This universality allows the same hardware structure to perform multiple functions, extending OLED lifetime through alternating drive without requiring separate dedicated circuits for each function.
4Productivity
If pulse signal with alternating phases is used to drive OLED, then charging efficiency is improved and display quality enhanced, but energy consumption increases
Solution Approach 1:
The patent applies periodic action through alternating drive cycles where pixel units switch between emitting and non-emitting states. This periodic operation improves charging efficiency by allowing capacitors to charge during active cycles and discharge during inactive cycles, while the alternating nature ensures that not all pixels are active simultaneously, thereby reducing overall energy consumption compared to continuous DC drive of all pixels.
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 solution extends the lifetime of OLEDs, eliminates the aging effect, improves display quality, and enhances the integration and touch sensing functionality of OLED displays by alternating the emission of adjacent pixels and doubling the charging time of the coupling capacitor.
Implementation Method 1
OLED emits light by the current generated from the driving transistor under saturated state
Data Source
AI summary
The present invention discloses an array substrate of OLED display, which comprises: multiple sub-pixel units defined by scanning control lines and data lines, each sub-pixel unit comprising a touch driving circuit, and the touch driving circuit comprising: a scanning transistor TFT1, a driving transistor TFT2, an organic light emitting diode OLED, a touch transistor TFT3, and a light sensing unit, so that the two adjacent organic light emitting diodes OLED in the adjacent frame cycles emit light alternately, and the light sensing unit connected with the organic light emitting diode OLED which does not emit light currently is in operation. In the embodiment of the present invention, it can improve the lifetime of the OLED and the display effects and the integration of the OLED displays.