Illuminated Vehicle Glass Panel with Refractive Index Matched Diffusing Layer
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Solution Overview
Problem
Conventional luminous vehicle glazing with light-emitting diodes (LEDs) suffers from a loss of transparency in the off state due to a diffusing layer that is too visible, and this comes at the cost of reduced luminance in the on state, while also being complex and costly to produce.
Innovation Solution
A motor vehicle glazing system featuring a glass module with a diffusing layer comprising microparticles and a transparent matrix, where the microparticles have a core and shell structure with a refractive index difference that enhances light scattering, allowing for a more transparent appearance in the off state without compromising luminance, and are dispersed in a polymeric binder for improved mechanical strength and ease of production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a diffusing layer is used to extract light from the glass module, then light extraction efficiency is improved, but transparency in the off state deteriorates
Solution Approach 1:
The patent changes the refractive index parameter of the diffusing particles to match closely with the glass matrix (n1-n2 ≤ 0.15). This parameter adjustment allows the particles to scatter light effectively when illuminated while remaining nearly invisible in the off state, thus improving light extraction efficiency without significantly compromising transparency.
Solution Approach 2:
The diffusing particles are applied locally only in specific zones where light extraction is needed, rather than uniformly across the entire glass surface. This localized application allows light extraction functionality to be concentrated in areas where it is most beneficial, while preserving transparency in other areas.
2Illumination intensity
If a diffusing layer with high scattering capability is used, then luminance in the on state is improved, but transparency in the off state deteriorates
Solution Approach 1:
The patent optimizes the refractive index contrast parameter (n1-n2) to be at most 0.15, creating a subtle but effective scattering capability. This moderate parameter change enables sufficient luminance enhancement in the on state while maintaining near-invisibility in the off state, avoiding the extreme contrast that would cause visible haze.
Solution Approach 2:
The patent uses a low concentration of diffusing particles (coverage rate of 1-10%) rather than a dense uniform layer. This partial action provides just enough scattering capability to enhance luminance when needed, while keeping the overall visual impact minimal in the off state.
3Illumination intensity
If conventional diffusing coatings are used, then light extraction is achieved, but production complexity and cost increase
Solution Approach 1:
The patent employs simple, inexpensive dielectric particles (such as glass beads or ceramic particles) that can be easily manufactured and applied. These particles replace complex, expensive conventional diffusing coatings, significantly reducing production complexity and cost while maintaining effective light extraction capability.
Solution Approach 2:
The patent specifies practical parameter ranges for the particles (refractive index difference ≤ 0.15, diameter 1-100 μm) that are easy to control in standard manufacturing processes. These parameter specifications enable simple, scalable production methods without requiring specialized equipment or complex processing steps.
4Illumination intensity
If the refractive index difference between glass and diffusing particles is large, then light scattering is enhanced, but transparency deteriorates
Solution Approach 1:
The patent precisely controls the refractive index parameter by selecting diffusing particles with refractive index n2 close to the glass refractive index n1 (difference ≤ 0.15). This parameter optimization creates a delicate balance where light scattering is sufficient for effective light extraction while the particles remain nearly invisible when the LED is off, preserving glass transparency.
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 solution provides a transparent appearance in the off state with minimal haze and high luminance in the on state, while being industrially viable due to its simplicity and cost-effectiveness, maintaining the clarity and functionality of the glazing.
Implementation Method 1
a diffusing layer comprising diffusing dielectric particles (spaced apart) and bound by a transparent matrix... The contrast in refractive indices between the core and the matrix (between n3 and n2) allows guided light scattering to be more efficient than usual solid scattering particles
Implementation Method 2
The light emitted by the LEDs is introduced edge-on into the inner glazing, which acts as a guide. The light is then extracted from the glazing by a diffusing layer on the glass
Data Source
Figure 1~1'
Figure 2~3
Figure 4~5
AI summary
The invention relates to an illuminated glass panel of a motor vehicle (100) comprising: - a glass module having an edge and main external faces, said module comprising a first glass panel (1), made of mineral or organic glass, with refractive index n1 of at least 1.4, having first and second main faces (11, 12), - a light source (4) coupled to the glass module, preferably to the first glass panel, the glass module forming a guide for light emitted by the light source, - light extraction means comprising a diffusing layer with a width of at least 1 cm containing dielectric diffusing particles (51) linked by a transparent matrix (5) of refractive index n2 at least equal to n1 or such that n1-n2 is at most 0.15. The majority of the diffusing particles are microparticles, spaced apart and comprising a transparent shell made of a dielectric material and in contact with the transparent matrix, the shells surrounding a core with refractive index n3 of at most 1.15 and having a largest dimension, referred to as D3, in a range from 5 μm to 200 μm, the microparticles having a largest dimension, referred to as D', of less than 2D3.