Laser Relief Pattern on Thin Plastic Card
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Solution Overview
Problem
Existing methods for producing relief patterns in thin plastic cards are limited in terms of relief thickness and design flexibility, with most methods achieving relief heights of less than 150 μm and restricting pattern complexity due to the use of punches or limited laser techniques.
Innovation Solution
A method involving a superposition of layers, including a transparent layer, a special layer with different thermal expansion indices, and a black surface, where a laser is used to create a relief pattern by modifying the special layer, allowing for greater relief thickness and design freedom, with the special layer comprising alternating reflective optical films and a black surface formed by printing or substrate tinting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If embossing with punch and die is used to produce relief pattern, then relief thickness can reach 400 to 500 μm, but the pattern freedom is limited to existing punches/die sets and a recessed relief appears on the opposite face
Solution Approach 1:
The patent replaces the mechanical embossing system (punch and die) with a laser-based system. The laser beam draws the pattern directly onto the card surface, eliminating the need for physical punches and dies. This substitution enables complete pattern freedom while maintaining precise control over relief thickness, as the laser can be programmed to create any desired pattern geometry without mechanical constraints.
Solution Approach 2:
The patent utilizes changes in material parameters under laser irradiation to create relief patterns. By controlling laser parameters (power, speed, pulse duration) and material properties (absorption coefficient, thermal conductivity), the process achieves precise control over relief depth and shape. This parameter-based control replaces the fixed geometry of mechanical punches with flexible, programmable laser parameters.
2Ease of manufacture
If laser carbonizing method is used to produce relief pattern, then relief thickness can reach up to 140 μm, but the relief thickness remains very limited compared to embossing
Solution Approach 1:
The patent exploits phase transitions of the card material under laser irradiation to generate relief patterns. The laser induces localized melting, vaporization, or decomposition of the plastic material, causing it to swell or reorganize into raised patterns. By controlling the phase transition process through laser parameters, the patent achieves relief thickness exceeding 140 μm while maintaining the ease of direct digital drawing capability.
Solution Approach 2:
The patent utilizes thermal expansion effects during laser irradiation to create relief patterns. The localized heating causes the material to expand and form raised features. By controlling the thermal process parameters (laser power, scanning speed, number of passes), the patent can achieve greater relief thickness than traditional carbonizing methods while maintaining the flexibility of direct laser drawing.
3Ease of manufacture
If screen printing or inkjet printing is used to produce relief pattern, then the process is simple, but the relief thickness does not exceed 100 μm
Solution Approach 1:
The patent replaces the material-deposition-based printing systems (screen printing, inkjet printing) with a direct energy-based laser system. Instead of depositing varnish or ink that dries to form relief, the laser directly modifies the card substrate through thermal processes. This substitution eliminates the thickness limitations of dried coating materials while maintaining process simplicity and digital programmability.
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 achieves relief heights exceeding 150 μm, providing significant design flexibility and durability, with reliefs persisting after laser application and cooling, allowing for precise and varied pattern creation on thin plastic cards.
Implementation Method 1
drawing by means of a laser of said pattern through the transparent layer
Implementation Method 2
a special layer shaped to modify under the effect of a laser beam, this layer comprising a chemical foaming agent
Data Source
Figure 1~2
Figure 3~4
AI summary
A method for producing a pattern (6) in relief (10) in a thin plastic card (1), comprising the following steps: - producing a stack of layers comprising, in the following order: - a transparent layer (2), - a special layer (3), - a black surface (4), - a substrate layer (5), - drawing said pattern (6) by means of a laser (7) through the transparent layer (2).