Variable-Frequency OLED Panel Driving for Luminance Uniformity
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Solution Overview
Problem
Existing light-emitting display devices face challenges in maintaining uniform luminance characteristics when the operating frequency varies, leading to inconsistencies in image quality.
Innovation Solution
A display device and driving method that includes a panel driver capable of operating in both fixed and variable frequency modes, with adjustments to duty ratios of emission and initialization control signals based on grayscale thresholds, ensuring consistent luminance across varying frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the operating frequency is varied to improve adaptability, then the display device can operate at different frame rates, but the luminance uniformity deteriorates
Solution Approach 1:
The patent applies dynamics by making the initialization voltage adjustable rather than fixed. The voltage generator dynamically changes the initialization voltage based on the operating frequency, allowing the system to adapt to varying frame rates while maintaining luminance uniformity. This resolves the contradiction by enabling frequency variation without sacrificing luminance consistency.
Solution Approach 2:
The patent changes the parameter of initialization voltage according to operating frequency. By varying the voltage level supplied to the pixel circuit unit based on the detected frame rate, the system maintains consistent luminance characteristics across different operating frequencies, thus resolving the contradiction between adaptability and luminance uniformity.
2Device complexity
If the initialization voltage is kept constant to simplify the voltage generator, then the device complexity is reduced, but the luminance uniformity deteriorates when frequency varies
Solution Approach 1:
The patent implements feedback by having the driving controller detect the operating frequency and use this information to control the voltage generator. The feedback loop ensures that the initialization voltage is automatically adjusted based on actual operating conditions, maintaining luminance uniformity without requiring complex manual intervention.
Solution Approach 2:
The patent applies preliminary action by pre-establishing a correspondence relationship between operating frequencies and appropriate initialization voltages. The voltage generator is configured to select predetermined voltage levels based on detected frame rates, allowing the system to proactively maintain luminance uniformity before frequency changes occur.
3Stability of the object's composition
If the duty ratio of emission control signal is adjusted to maintain luminance, then the luminance uniformity is improved, but the control complexity increases
Solution Approach 1:
The patent segments the control process into distinct phases: frequency detection, voltage selection, and duty ratio adjustment. By dividing the control function into these separate stages handled by different components (driving controller and voltage generator), the system achieves luminance uniformity while keeping the overall control architecture manageable and not excessively complex.
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
The solution maintains uniform luminance characteristics across different operating frequencies, enhancing image quality and consistency in light-emitting display devices.
Implementation Method 1
displays an image by a light-emitting diode that generates light through recombination of electrons and holes
Data Source
AI summary
A display device includes a display panel including a plurality of pixels and a panel driver that drives the display panel in a first mode where an operating frequency is fixed, and a second mode where the operating frequency is variable. Each of the plurality of pixels includes a light-emitting element and a pixel driving circuit connected to a first electrode of the light-emitting element. The panel driver includes a driving controller that determines whether the operating frequency corresponds to one of predetermined compensation frequencies in the second mode, and outputs a voltage control signal depending on the determination result, and a voltage generator that changes a voltage level of an anode initialization voltage applied to the first electrode in response to the voltage control signal.