Transparent Laserable Layer for High Reflectivity Color Images
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Solution Overview
Problem
Existing methods for enhancing the reflective yield and luminosity of color laser images, such as adding a white sub-pixel, often result in color superimposition and inadequate reflectivity, leading to image quality issues in documents like identity cards and passports.
Innovation Solution
The method involves printing sub-pixels in primary colors on a transparent laserable material, with non-printed transparent regions between them, and then carbonizing the material using a laser to create grey levels and enhance reflectivity, maintaining contrast and preventing color overlap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a white sub-pixel is added to reinforce luminosity and white component, then the luminosity of the image is improved, but color superimposition occurs which is detrimental to image quality
Solution Approach 1:
The patent removes the white sub-pixel from the pixel structure entirely. Instead of adding a fourth white sub-pixel to RGB, the invention uses only the three RGB sub-pixels and creates white perception through additive mixing of their reflected light beams, thereby eliminating color superimposition issues while maintaining luminosity.
Solution Approach 2:
The patent changes the optical parameters of the protective layer by making it transparent and laserable. This allows the protective layer to serve dual functions: protecting the sub-pixels and enabling laser-based personalization. The transparency ensures that light can pass through to reflect off the sub-pixels without being blocked, maintaining luminosity without requiring a white sub-pixel.
2Area of stationary object
If sub-pixels are printed closely to maximize pixel surface, then area efficiency is improved, but color overlap occurs which degrades image quality
Solution Approach 1:
The patent introduces a transparent protective layer as an intermediary between the printed sub-pixels and the external environment. This layer prevents direct contact and potential mixing of color inks from adjacent sub-pixels, while its transparency ensures it does not interfere with light reflection. The protective layer acts as a physical barrier that maintains color separation while allowing optical functions to proceed normally.
3Illumination intensity
If additional light source is used to illuminate sub-pixels for clear white appearance, then luminosity is improved, but device complexity increases
Solution Approach 1:
The patent makes the protective layer itself serve the dual function of protection and light transmission. By making the protective layer transparent and laserable, it enables the sub-pixels to self-illuminate through ambient light reflection without requiring additional light sources. The system uses the environmental light that would otherwise be wasted, converting it into useful illumination through the reflective properties of the sub-pixels and the transparent protective layer.
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 approach significantly improves the reflective yield and luminosity of color laser images, ensuring high-quality images are visible in ambient light without additional light sources, while preventing color superimposition and maintaining precise image rendering.
Implementation Method 1
The sheet of laserable material is then partly carbonized under the effect of a laser beam to form non-reflective surfaces above the sub-pixels and to produce grey levels of a personalised image
Implementation Method 2
Since the surfaces of the printed sub-pixels are not adjacent one another, they expose non-printed surfaces which, via transparency and reflection on a substantially white reflective layer, increase the luminosity of the laser image
Data Source
AI summary
A method for forming and a document having a color laser image with high reflective yield, which comprises a sheet of laserable material, sub-pixels in primary colors, the laser beam via carbonization exposing grey levels of the color image, and a substrate. The whole is laminated in various embodiments. The sub-pixels in various embodiments are separated by transparent regions which increase reflectivity and reinforce the white component of the personalised image. Layers of reflective varnish can reinforce reflectivity.