Defective Pixel Correction Circuit for Current-Drive Displays
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Solution Overview
Problem
In display devices with current drive type light emitting elements, defective pixels that are short-circuited can consume excessive current even when they do not emit light, leading to inefficiency and reduced luminance.
Innovation Solution
A display device with a display panel comprising current drive type light emitting elements, an image processing circuit, a pixel voltage input circuit, and a defect detecting circuit that corrects the pixel value of defective pixels to black, thereby reducing current consumption and compensating for luminance loss by adjusting related pixel values based on positional relationships and elapsed time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current drive type light emitting elements are used in display pixels, then luminance control precision is improved, but current consumption increases in defective pixels with short-circuited anodes and cathodes
Solution Approach 1:
The defect detecting circuit performs preliminary detection of defective pixels before normal display operation. By identifying short-circuited pixels in advance and storing their positions, the system can prevent excessive current consumption during subsequent display operations by correcting pixel values for detected defective pixels.
Solution Approach 2:
The invention converts the harmful effect of defective pixels (short-circuited anodes and cathodes causing excessive current consumption) into a manageable issue by detecting and correcting pixel values through software processing. The correction circuit replaces defective pixel values with neighboring pixel values, transforming the harmful short-circuit condition into a corrected display output.
2Ease of manufacture
If defective pixels with short-circuited anodes and cathodes are present, then manufacturing yield is improved, but current consumption increases and luminance decreases
Solution Approach 1:
The display device performs self-diagnosis and self-correction by incorporating a defect detecting circuit that automatically identifies defective pixels and a correction circuit that automatically corrects their pixel values. This self-service mechanism allows the system to maintain proper current consumption and luminance without external intervention, compensating for manufacturing defects.
Solution Approach 2:
The defect detecting circuit provides feedback information about defective pixel positions to the correction circuit. This feedback loop enables the system to continuously monitor and correct for defective pixels, ensuring that current consumption and luminance remain within acceptable ranges despite manufacturing variations.
3Device complexity
If defective pixels are not corrected, then device complexity is reduced, but luminance uniformity deteriorates
Solution Approach 1:
The image processing circuit performs multiple functions: normal image processing, defect detection, and pixel value correction. By integrating these functions into a single circuit, the system maintains luminance uniformity without adding separate complex correction hardware, thus balancing functionality with complexity management.
Data Source
AI summary
A display device is provided with an image processing circuit that outputs a pixel value of each pixel to a pixel driving circuit, the pixel driving circuit that inputs a pixel voltage to each of pixels based on the pixel value of each of the pixels, and a control circuit that detects a defective pixel. Here, the image processing circuit corrects the pixel value of the defective pixel in the image data to be displayed which is input to the image processing circuit, to a pixel value for black, and then outputs each pixel value of the image data to be displayed in which the pixel value of the defective pixel is corrected to the pixel value for black, to the pixel driving circuit.