Colloidal Crystal Detection Film for Mini LED Chip Tilt Inspection
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Solution Overview
Problem
Current methods lack an effective means to detect whether mini light-emitting diode (LED) chips bonded to a circuit board are tilted, which can affect display quality due to variations in light-emitting angles.
Innovation Solution
A detection film with colloidal crystal microspheres is used, which covers the bonded chip and utilizes the Bragg reflection effect to determine tilt angles by analyzing light reflected from the microspheres, allowing for the detection and classification of tilted chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reflow soldering is performed at high temperature to bond LED chips to PCB, then bonding strength is improved, but chip tilt occurs affecting display quality
Solution Approach 1:
The detection film is applied to the chip surface before the reflow soldering process. The colloidal crystal microspheres in the film pre-establish a reference structure that will reflect light differently based on any tilt that occurs during bonding, allowing detection of the tilt angle after bonding without requiring post-process measurement equipment.
Solution Approach 2:
The colloidal crystal microspheres in the detection film exhibit Bragg reflection that causes color changes in reflected light based on the tilt angle of the chip. Different tilt angles produce different reflected colors, enabling visual or instrumental detection of chip orientation after bonding.
2Device complexity
If no detection means is used during chip bonding, then manufacturing complexity is reduced, but tilt detection capability is lost
Solution Approach 1:
The detection film acts as an intermediary between the chip and the detection system. Instead of requiring complex external measurement equipment, the film itself contains the detection mechanism through its colloidal crystal structure that naturally responds to tilt angles via Bragg reflection, simplifying the overall detection system.
Solution Approach 2:
The detection film is self-contained with the colloidal crystal microspheres that automatically provide tilt detection functionality. The film serves both as a protective coating and as the detection element itself, eliminating the need for separate detection devices and reducing system complexity.
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 method enables the accurate detection of tilted chips, improving display quality by preventing poor light emission and enabling targeted maintenance and splicing of display panels, thus enhancing the overall performance and yield of LED display products.
Implementation Method 1
based on a Bragg reflection effect of the colloidal crystal microspheres, according to the characteristic that light reflected by colloidal crystal microspheres corresponding to chips having difference tilt angles after bonding varies
Data Source
AI summary
The disclosure relates to a detection film and a manufacturing method therefor, a detection method and device for chip bonding, and a classification method. A detection film (2) covers a chip bonded to a circuit board (11), the detection film (2) is internally provided with colloidal crystal microspheres (22) arranged in order, and based on a Bragg reflection effect of the colloidal crystal microspheres, whether each chip is tilted is determined according to light reflected by the colloidal crystal microspheres (22) on the chip.