Pixel Compensation Circuit for Display Substrate Defects
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Solution Overview
Problem
Electrical defects during the bonding process of electroluminescence (EL) devices in display manufacturing lead to reduced conduction current and brightness, resulting in lower yield due to pre-process defects like pollution interference or equipment errors.
Innovation Solution
A pixel compensation circuit comprising a detecting circuit, a repairing circuit, and a compensating circuit that provides a fixed current to the EL device, detects electrical defects, and applies a calculated compensation voltage to stabilize the current output, thereby compensating for non-ideal electrical parameters of the Thin Film Transistor (TFT) and repairing electrical defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bonding process is used to connect the EL device with the drive circuit, then the current-controlled light emission function can be achieved, but electrical defects occur due to pre-process defects (pollution interference, equipment errors), reducing conduction current and brightness
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the EL device parameters (threshold voltage, saturation current) before bonding, and pre-calculating compensation values. The compensation circuit is designed in advance to counteract expected bonding defects, allowing the system to compensate for electrical defects caused by pollution or equipment errors during the bonding process.
Solution Approach 2:
The patent implements feedback by measuring the actual conduction current after bonding and comparing it with the expected current. Based on this feedback, the compensation circuit adjusts the drive signal to maintain the desired luminous current, thereby compensating for electrical connection defects introduced during bonding.
2Manufacturing precision
If misalignment or foreign objects occur during bonding, then resistance increases (RE>0, VD>0), but this results in decreased voltage across the EL device and reduced luminous current
Solution Approach 1:
The patent uses feedback to detect the actual voltage and current conditions at the EL device terminals after bonding. When misalignment or foreign objects cause increased resistance, the feedback mechanism identifies the deviation and triggers compensation by adjusting the drive signal to maintain proper conduction current despite the elevated resistance.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the gate voltage or drive current parameters in response to detected bonding defects. When resistance increases due to misalignment or contamination, the system modifies operating parameters (such as increasing drive voltage) to compensate for the degraded electrical connection and maintain reliable conduction.
3Illumination intensity
If the conduction current decreases due to bonding defects, then the brightness of the EL device decreases, but this leads to lower production yield
Solution Approach 1:
The patent implements feedback by monitoring the actual brightness output and conduction current of each EL device. When bonding defects cause current reduction and brightness decrease, the feedback system identifies these deviations and triggers compensation mechanisms to restore the display to acceptable brightness levels, thereby preventing defective units from being discarded and improving production yield.
Solution Approach 2:
The patent applies parameter changes by adjusting drive current, gate voltage, or pulse width modulation parameters in response to detected brightness deficiencies. When bonding defects reduce conduction current and thus brightness, the system modifies these parameters to compensate and maintain the required luminous output, allowing devices that would otherwise be rejected to meet specifications and improving overall yield.
Data Source
AI summary
A pixel compensation circuit is provided. The pixel compensation circuit includes a detecting circuit, a repairing circuit, a compensating circuit, and a light-emitting device. The detecting circuit is electrically coupled with the repairing circuit, the compensating circuit, and the light-emitting device. The compensating circuit is configured to provide a fixed current to the light-emitting device. The detecting circuit is configured to detect a current flowing through the light-emitting device. The repairing circuit is configured to determine a compensation current according to the current detected by the detecting circuit and input the compensation current into the light-emitting device. A display substrate and a display device are further provided.