Display Device Gain Control for Luminance Stability
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Solution Overview
Problem
Existing display devices face image quality deterioration due to repeated changes in average current values of input signals, leading to unstable luminance and overcurrent issues in light-emitting elements, as existing ABL control methods do not consider the speed of gain response to signal changes.
Innovation Solution
A display device and integrated circuit with a temporal direction control unit that adjusts the speed of gain response to input video signals, causing the gain to respond quickly when the signal sharply increases and slowly when it gently increases, thereby stabilizing luminance and preventing overcurrent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gain control is performed to limit luminance and prevent overcurrent, then the light-emitting element is protected from damage, but the gain response repeatedly fluctuates when the input signal changes, causing image quality deterioration
Solution Approach 1:
The patent applies dynamics by making the gain control characteristics adaptable rather than fixed. The control unit dynamically adjusts the gain response speed based on the temporal direction of signal changes - responding quickly to sharp increases to prevent overcurrent, and slowly to gentle increases to maintain stable luminance. This dynamic adaptation resolves the contradiction between protection and stability.
Solution Approach 2:
The patent changes the parameter of gain response speed based on signal characteristics. By detecting whether the input signal is sharply increasing or gently increasing, the system adjusts the gain control parameter accordingly - using aggressive gain reduction for sharp increases and moderate gain reduction for gentle increases. This parameter change strategy simultaneously achieves element protection and luminance stability.
2Reliability
If the gain responds quickly to input signal changes, then overcurrent is prevented, but the luminance of the displayed image repeatedly increases and decreases, deteriorating image quality
Solution Approach 1:
The patent makes the gain response speed dynamic rather than fixed. The control unit adapts the response speed based on the temporal direction of signal changes - using fast response for sharp signal increases to prevent overcurrent, and slow response for gentle increases to maintain stable luminance. This dynamic adjustment resolves the contradiction between overcurrent prevention and image quality.
Solution Approach 2:
The patent applies local quality by differentiating the gain control strategy based on the local characteristics of signal changes. Instead of using a uniform gain response for all signal changes, the system applies different gain control characteristics - aggressive control for sharp increases and moderate control for gentle increases. This localized approach allows simultaneous achievement of overcurrent prevention and stable luminance.
3Device complexity
If uniform gain control is applied to all signal changes, then the control logic is simple, but the luminance stability deteriorates when signals with different temporal characteristics are input
Solution Approach 1:
The patent introduces dynamic adaptation to the gain control logic, making it context-aware rather than uniform. The control unit detects the temporal direction of signal changes and adjusts the gain control characteristics accordingly. This dynamic approach maintains relatively simple control logic while significantly improving luminance stability by adapting to different signal characteristics.
Solution Approach 2:
The patent changes the gain control parameters based on signal temporal characteristics. By detecting whether the input signal is sharply increasing or gently increasing, the system adjusts the gain reduction parameter - applying stronger gain control for sharp increases and milder control for gentle increases. This parameter adaptation improves luminance stability without substantially complicating the control logic.
Data Source
AI summary
There is provided a display device including a temporal direction control unit that causes a gain used to control a video signal to respond to an input video signal at high speed when the input video signal sharply increases, and causes the gain to respond to the input video signal at low speed when the input video signal gently increases.