Flat Panel Display Inspection Sampling Pixels Binary Conversion
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Solution Overview
Problem
Conventional methods for inspecting flat panel displays (FPDs) are inefficient due to unstable light luminance and require significant time, especially when the proportion of stains is small, making it difficult to accurately detect defects in a timely manner.
Innovation Solution
An apparatus comprising a lighting device, a photographing device, a controller, and an image processor that samples pixels at predetermined intervals and converts them to binary form based on threshold values, allowing for efficient defect detection by representing pixels as either one or zero, thereby reducing inspection time without compromising accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If automatic inspection using a camera is used to photograph and analyze the FPD image, then defect detection capability is improved, but inspection time increases significantly
Solution Approach 1:
The patent divides the image processing task into segments by sampling only specific pixels (e.g., every nth pixel in x and y directions) rather than processing all pixels. This segmentation of the pixel set reduces the total number of pixels to be converted to binary form, thereby maintaining defect detection capability while significantly reducing inspection time.
2Measurement precision
If conventional optical inspection method is used with stable light luminance, then defect detection accuracy is improved, but inspection time increases
Solution Approach 1:
The patent applies partial action by converting only a subset of pixels (sampled pixels) to binary form rather than all pixels. This partial processing approach maintains sufficient defect detection accuracy for practical purposes while reducing the time required for image processing.
3Measurement precision
If all pixels in the photographed image are converted to binary form, then defect detection accuracy is improved, but processing time increases
Solution Approach 1:
The patent segments the pixel population into sampled and non-sampled groups, processing only the sampled pixels for binary conversion. This segmentation reduces the computational load and processing time while maintaining adequate defect detection capability through strategic sampling.
Solution Approach 2:
The patent performs partial conversion of pixels to binary form by selecting a subset of pixels for processing. This partial action approach achieves sufficient processing speed for production inspection while maintaining adequate defect detection accuracy.
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 method significantly reduces inspection time while maintaining the accuracy of conventional inspection methods, particularly when the proportion of stains in the FPD is small, by efficiently processing images and identifying defects in a reduced timeframe.
Implementation Method 1
light emitted from a light source reaches the FPD (i.e., a subject) after passing sequentially through a mirror, a lens, a liquid crystal plate, etc.
Implementation Method 2
a lighting device being separated from a top surface of an object and emitting light toward the top surface of the object
Data Source
AI summary
In a method and apparatus for optically inspecting an FPD in a reduced time, the apparatus for inspecting the flat panel display (FPD) comprises a lighting device separated from a top surface of an object and emitting light toward the top surface of the object, a photographing device separated from the top surface of the object and photographing an image using light emitted from the lighting device and then reflected by the top surface of the object, a controller controlling the lighting device and the photographing device to move in a plane separated from and parallel to the top surface of the object, and an image processor connected to the photographing device and processing the photographed image, wherein the image processor samples some of pixels included in the photographed image and converts the sampled pixels to binary form.