Phased Array Acousto-Optic Deflector for Laser PCB Drilling Precision
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Solution Overview
Problem
Mechanical drilling in PCB manufacturing struggles to create small, precise holes with high aspect ratios, leading to issues with signal integrity and manufacturing yield as PCBs become smaller and more complex.
Innovation Solution
A laser drilling system utilizing a phased array acousto-optic deflector (AOD) with a laser oscillator, beam splitter, damper, galvano deflection unit, and condensing lens for precise control of the laser beam, enabling efficient drilling of small, high-aspect-ratio holes by controlling the direction and focus of the laser beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical drilling is used to create vias in PCBs, then the manufacturing process is simple and fast, but it is difficult to achieve small, precise holes with high aspect ratios
Solution Approach 1:
The patent replaces the mechanical drilling system with a laser-based drilling system. The laser beam is focused to a small spot size to create precise, small-diameter holes with high aspect ratios. The laser system includes optical components for beam focusing and positioning, eliminating the need for physical drill bits and mechanical feeding mechanisms, thereby achieving high precision without proportionally increasing manufacturing complexity.
Solution Approach 2:
The patent changes the physical parameters of the drilling process by using laser energy instead of mechanical force. Key parameters include laser wavelength, pulse duration, peak power, and focal spot size. By optimizing these parameters, the system achieves high aspect ratio holes (depth-to-diameter ratio) with precise dimensional control, overcoming the limitations of mechanical drilling where drill bit geometry constrains the achievable aspect ratio.
2Manufacturing precision
If laser drilling is used to create small, precise holes with high aspect ratios, then manufacturing precision is improved, but processing time increases due to sequential trepanning and punching operations
Solution Approach 1:
The patent applies preliminary action by first irradiating the copper layer to create an initial opening or pre-hole before performing the main punching operation. This pre-processing step modifies the material structure ahead of time, reducing the energy required for subsequent drilling and enabling faster processing. The system uses controlled laser irradiation to prepare the copper layer, making the final hole creation more efficient.
Solution Approach 2:
The patent employs periodic action through pulsed laser drilling instead of continuous irradiation. The laser delivers high-energy pulses with specific duty cycles, allowing the material to cool between pulses and prevent excessive heat accumulation. This pulsed regime enables precise hole creation with controlled depth and diameter while maintaining high processing speeds by rapidly repeating the pulse sequence.
3Manufacturing precision
If the laser beam diameter is reduced to increase energy density for copper layer processing, then manufacturing precision is improved, but the area of laser application decreases
Solution Approach 1:
The patent transitions from two-dimensional beam scanning to three-dimensional focused drilling. By concentrating laser energy in the third dimension (depth) through precise focusing, the system achieves high energy density at the focal point while the beam waist diameter remains small. This dimensional focus allows sufficient energy delivery for deep hole drilling without requiring a large beam area, maintaining precision while achieving the necessary energy concentration.
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 system achieves high accuracy and consistency in creating small, precise holes with high aspect ratios, improving the performance and reliability of electronic devices by reducing the risk of heat damage and enabling drilling through various materials.
Implementation Method 1
a phased array acousto-optic deflector (AOD) with one or more transducers
Implementation Method 2
a condensing lens to generate one or more laser beams directed at the electronic circuit
Implementation Method 3
The ability to create small, precise holes with high aspect ratios
Data Source
AI summary
A laser apparatus includes laser, a beam splitter, a phased array acousto-optic deflector (AOD) with one or more transducers, a damper, a galvano deflection unit, and a condensing lens to generate one or more laser beams directed at the electronic circuit. The Galvano deflection unit works with acousto-optic deflector includes an optical element having a surface with one or more steps formed thereon; a conductive layer formed on the surface with the steps; one or more crystals secured to each step; and electrodes positioned on each surface of each crystal.