Wafer Decoration Laser System with Extended Depth of Field
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Solution Overview
Problem
Conventional methods for decorating wafers, such as stamping, embossing, and laser technology with masks, are time-consuming, require additives, and damage the fragile structure of wafers, especially when creating designs on non-planar surfaces like cones.
Innovation Solution
A laser-based decorating apparatus using a CO2 laser, collimator, galvanometer-driven mirrors, and an aspheric scan lens, which positions the wafer surface outside the focal plane to achieve a larger spot size and deeper focal depth, allowing for detailed, high-resolution decorations on curved surfaces without damaging the wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional stamping or embossing is used to decorate wafers, then decorations can be created on the wafer surface, but the process is time-consuming and interferes with subsequent shaping steps
Solution Approach 1:
The patent replaces mechanical stamping and embossing systems with a laser-based decorating system. The laser beam (electromagnetic energy) directly heats and carbonizes the wafer surface to create decorations, eliminating the need for physical contact with stamps or embossing tools. This substitution enables rapid processing without interfering with subsequent shaping operations, as the laser can be applied after the wafer is formed into its final shape.
Solution Approach 2:
The patent utilizes changes in laser parameters (power, pulse duration, scanning speed) to control the decoration process. By adjusting these parameters, the laser can selectively carbonize the wafer surface to create various decoration patterns without mechanical contact. The process operates at temperatures that cause localized carbonization (color change) without compromising the overall wafer structure or interfering with shaping steps.
2Manufacturing precision
If masks are used with laser technology to define decoration shapes, then precise decorations can be created, but additional apparatus and processing steps are required which increase cost and decrease line speed
Solution Approach 1:
The patent extracts and eliminates the mask component from the laser decorating system. Instead of using physical masks to define decoration patterns, the invention employs computer-controlled galvanometer-driven mirrors to directly steer the laser beam along precise paths. This extraction removes the complexity of mask handling, alignment, and replacement while maintaining or improving decoration precision through digital control.
Solution Approach 2:
The patent uses digital copies or representations of decoration designs stored in computer memory. These digital patterns are translated into control signals for the galvanometer mirrors, which guide the laser beam to reproduce the desired decoration patterns on the wafer surface. This digital copying approach eliminates the need for physical masks while maintaining design fidelity.
3Manufacturing precision
If a focussed laser beam is used to heat the wafer surface, then detailed decorations can be created, but the laser penetrates the fragile wafer structure causing damage
Solution Approach 1:
The patent applies partial action by using a defocused laser beam that delivers sufficient energy to carbonize the wafer surface for decoration purposes without concentrating enough energy to penetrate or damage the fragile wafer structure. The laser beam is intentionally allowed to diverge slightly, distributing the energy over a larger area to achieve surface heating without the harmful effects of deep penetration.
Solution Approach 2:
The patent optimizes laser parameters including power level, pulse duration, scanning speed, and focal position to achieve the desired balance. By carefully controlling these parameters, the laser delivers just enough energy to cause surface carbonization for decoration while avoiding the excessive energy concentration that would lead to wafer penetration or structural damage.
4Manufacturing precision
If conventional laser engraving with a flat focal plane is used, then high resolution decorations can be created on flat surfaces, but the technique cannot accommodate curved and sloping surfaces of shaped wafers
Solution Approach 1:
The patent introduces dynamics by making the laser beam's focal plane adjustable and movable. The system uses computer-controlled galvanometer mirrors that can dynamically reposition the laser beam to follow curved and sloping surfaces. This dynamic adjustment allows the laser to maintain appropriate focus and angle across various surface geometries, enabling high-resolution decorations on both flat and curved wafer surfaces.
Solution Approach 2:
The patent adds the dimension of angular adjustment to the laser decorating system. By controlling the tilt and orientation of the laser beam through galvanometer mirrors, the system can accommodate surfaces in three-dimensional space, not just flat two-dimensional planes. This enables the laser to track and decorate curved, sloping, and complex surface geometries while maintaining decoration quality.
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 rapid, controllable, and high-resolution decorations on wafer-based products like cones without using additives or masks, ensuring the structural integrity of the wafers and accommodating uneven surfaces.
Implementation Method 1
Other approaches have been disclosed which use laser technology to directly heat the surface of the wafer itself, further cooking the wafer to darken the material and create a contrasting pattern or decoration
Implementation Method 2
The laser beam is allowed to diverge slightly so that it provides a spot size of from 100 to 750 μm in diameter on the surface of the wafer-based product that is to be decorated
Implementation Method 3
an aspheric scan lens, the apparatus being positionable relative to the product to be decorated wherein the apparatus is configured to provide a laser beam having a spot size of from 100 to 750 μm in diameter on the surface of the wafer product to be decorated and a substantially flat focal plane
Implementation Method 4
the focal plane has a depth of field of from 5 mm to 20 mm
Implementation Method 5
a pyrographic approach in which a heated stamp is applied to the surface of the wafer such that the carbohydrates and sugars in the wafer undergo a colour change to a darker colour
Implementation Method 6
further cooking the wafer to darken the material and create a contrasting pattern or decoration
Data Source
AI summary
The present invention provides a wafer product decorating apparatus comprising a laser, a collimator, at least one galvanometer driven mirror, and an aspheric scan lens, the apparatus being positionable relative to the wafer product to be decorated wherein the apparatus is configured to provide a laser beam having a spot size of from 100 to 750 μm in diameter on the surface of the product to be decorated and a substantially flat focal plane, characterised in that the focal plane has a depth of field of from 5 mm to 20 mm and that the focal plane of the laser beam is from 5 mm to 30 mm above or below the surface of the product to be decorated. The invention also provides a process for decorating a wafer product.