Thin Film Thickness Measurement Using Fast Fourier Transform
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Solution Overview
Problem
Existing thickness measuring methods for thin films in display devices have low measurement accuracy due to differences between the thickness of thin films in the tag area and the display area, requiring separate tag areas for measurement.
Innovation Solution
A thickness measuring device comprising a light source circuit, detector circuit, and control circuit that uses a light source to irradiate light, a lens to magnify light, and a spectrometer to measure reflectance spectrum data, performing a fast Fourier transform to calculate the thickness of thin films, allowing for direct measurement within the display area without a separate tag area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate tag area is manufactured to enable thickness measurement, then measurement can be performed, but measurement accuracy is low due to thickness differences between tag area and display area
Solution Approach 1:
The patent extracts the measurement function from a separate tag area and integrates it directly into the display area. By removing the need for a dedicated tag area and performing measurements within the display area itself, the system eliminates the accuracy problem caused by thickness differences while simplifying the overall structure.
Solution Approach 2:
The patent merges the measurement function with the display area, allowing thickness measurement to be performed on the same area where the display functions. This integration ensures that the measured thickness directly reflects the actual display area characteristics, improving measurement accuracy while eliminating redundant structures.
2Measurement precision
If a separate tag area is manufactured for measurement, then thickness can be measured, but the measurement does not reflect the actual display area thickness
Solution Approach 1:
The patent makes the display area serve dual functions: both as the functional display region and as the measurement region. By enabling the display area to perform both its primary function and the measurement function, the system eliminates the need for separate tag area materials, reducing overall material usage while ensuring measurement relevance.
3Productivity
If traditional measurement methods are used with tag areas, then measurement can be performed, but real-time measurement during manufacturing is not achieved
Solution Approach 1:
The patent enables continuous thickness measurement during the manufacturing process by integrating the measurement function directly into the display area. This allows for real-time monitoring of thin film thickness as layers are deposited, enabling immediate detection and correction of thickness variations, thus improving both productivity and measurement 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
This approach increases measurement accuracy by enabling the selective measurement of the organic layer's thickness across the entire substrate area, eliminating the need for a separate tag area and directly measuring the thickness within the display area, thereby improving precision.
Implementation Method 1
a light source which irradiates light to a surface of a substrate including a plurality of thin films and a lens which magnifies light emitted from the light source or reflected from the surface of the substrate
Implementation Method 2
a lens which magnifies light emitted from the light source or reflected from the surface of the substrate
Implementation Method 3
a spectrometer which measures reflectance for each wavelength of light reflected from the surface of the substrate and passed through the lens to generate reflectance values and which derives reflectance spectrum data for each wavelength form the reflectance values
Data Source
AI summary
A thickness measuring device includes: a light source circuit including: a light source which irradiates light to a surface of a substrate including a plurality of thin films and a lens which magnifies light emitted from the light source or reflected from the surface of the substrate, a detector circuit including a spectrometer which measures a reflectance for each wavelength of light reflected from the surface of the substrate and passed through the lens to generate reflectance values and which derives reflectance spectrum data for each wavelength from the reflectance values, and a control circuit which converts the reflectance spectrum data for each wavelength into a digital signal and calculates a thickness of at least one thin film among the plurality of thin films by performing fast Fourier transform on the digital signal.