Vehicle Interior Trim Lighting Homogeneity via Boundary Structuring
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Solution Overview
Problem
Existing lighting apparatuses in motor vehicles often experience light inhomogeneity at the boundary regions of line lighting due to light superposition at the ends of the light guide, leading to uneven illumination.
Innovation Solution
A lighting apparatus with a light guide strip featuring point light sources aligned along the light-entry face and boundary structuring, such as prisms, to ensure consistent spacing and output coupling, minimizing superpositions and achieving a homogeneous light image across the entire length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light sources are arranged along the light-entry face of the light guide strip, then line lighting is produced in the interior trim piece, but light inhomogeneity occurs at the boundary regions due to light superposition at the ends of the light guide
Solution Approach 1:
The patent applies local quality by implementing boundary structuring (such as prisms or roughened surfaces) specifically at the end sides of the light guide strip. This local modification changes the light output characteristics only at the boundary regions where inhomogeneity occurs, while leaving the main body of the light guide unchanged. The boundary structuring creates additional light extraction at the ends, compensating for the light superposition effect and achieving homogeneous line lighting throughout.
2Loss of energy
If the light guide strip uses total-internal reflection to guide light, then light is efficiently transmitted along the light guide, but light reflects at the end sides and superposes on the visible light guide side causing inhomogeneity
Solution Approach 1:
The patent converts the harmful light reflection at the end sides into a beneficial effect. The boundary structuring at the end sides causes light that would otherwise reflect and create inhomogeneity to instead be extracted usefully from the light guide. The prisms or roughened surfaces transform the total-internal-reflection condition into controlled light extraction, turning the problematic boundary reflection into additional light output that compensates for the superposition effect and creates homogeneous illumination.
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 ensures a homogeneous light image is produced over the entire light guide length by controlling light output at the ends, reducing unwanted reflections and superpositions, resulting in a uniform illumination experience for vehicle occupants.
Implementation Method 1
the light guide has a deflection face from which light that is incident by way of total-internal reflection is reflected toward the exit face
Implementation Method 2
the light guide side may have, at least in portions, a boundary structuring configured to output couple light at the end sides
Data Source
AI summary
A lighting apparatus may be provided for an interior trim piece of a motor vehicle. The lighting apparatus comprises a light guide strip, comprising at least one light-entry face and a light-exit face, which each extend along a longitudinal direction of the light guide strip, and at least two end sides, lying opposite one another and respectively adjoining the light-entry face or light-exit face. A plurality of point light sources are arranged at the light-entry face. Moreover, the light sources are arranged at an unchanging light source spacing from one another. Here, a boundary spacing between a respective end side and a light source arranged closest to the respective end side corresponds to at most half the light source spacing. Moreover, the light guide strip has, at least in portions, a boundary structuring for at least partial output coupling of light at the end sides.