Dichroic Fluorescence Inspection for LED Color Irregularity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the quality of light-emitting elements using photoluminescence fluorescence separation are inadequate for accurately deriving color irregularity due to insufficient wavelength separation of fluorescence, particularly for narrow wavelength widths.
Innovation Solution
An inspection apparatus and method that utilizes an optical element with a wider edge shift width than the full width at half maximum of the fluorescence spectrum, combined with image processing to correct wavelength shifts and adjust illumination luminance, to accurately separate and analyze fluorescence by wavelength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical element with narrow edge shift width is used, then the resolution of fluorescence separation is improved, but the ability to separate narrow wavelength width fluorescence deteriorates
Solution Approach 1:
The patent changes the key parameter of the optical element from narrow edge shift width to wide edge shift width (wider than the full width at half maximum of the fluorescence spectrum). This parameter change ensures that the optical element can effectively separate fluorescence with narrow wavelength width while maintaining sufficient resolution, thereby resolving the technical contradiction between resolution and separation accuracy.
2Reliability
If the edge shift width of the optical element is excessively widened, then the separation of fluorescence into short and long wavelength sides is improved, but the resolution of the optical element is lowered
Solution Approach 1:
The patent precisely controls the edge shift width parameter within a specific range (wider than the full width at half maximum of the fluorescence spectrum but not excessively wide). This optimized parameter setting achieves the balance between effective fluorescence separation and maintaining sufficient optical element resolution, resolving the contradiction between separation effectiveness and measurement precision.
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
Enables high-accuracy derivation of color irregularity in light-emitting elements by effectively separating fluorescence into short and long wavelength sides, allowing for precise identification of defective products.
Implementation Method 1
photoluminescence (specifically, fluorescence) emitted by the light-emitting element
Implementation Method 2
a dichroic mirror that reflects light having a specific wavelength and transmits light having other wavelengths
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An inspection apparatus is an inspection apparatus for inspecting a sample in which a plurality of light-emitting elements is formed, and includes an excitation light source that generates excitation light to irradiate the object, a dichroic mirror that separates fluorescence from the sample by transmitting or reflecting the fluorescence according to a wavelength, a camera that images fluorescence reflected by the dichroic mirror, a camera that images fluorescence transmitted through the dichroic mirror, and a control apparatus that derives color irregularity information of a light-emitting element based on a first fluorescence image acquired by the camera and a second fluorescence image acquired by the camera, and an edge shift width corresponding to a width of a wavelength band in which transmittance and reflectance change according to a change in wavelength in the dichroic mirror is wider than a full width at half maximum of a normal fluorescence spectrum of the light-emitting element.