Automotive Light Guide Bar with Arched Deflector Prisms
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Solution Overview
Problem
The existing backlighting systems using photoconductive-material bars in automotive rear lights face issues with non-uniform light extraction at branches, leading to irregular intensity distribution and the need for additional LEDs to compensate, resulting in increased costs.
Innovation Solution
The design incorporates a light-guide bar with deflector prisms that have a bulging/arched active deflector surface at the branching points, allowing for uniform light distribution without the need for additional LEDs by redirecting light rays effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light-guide bar with branches is used to backlight ribbon-like portions, then the number of LEDs is reduced and cost is saved, but the light extraction becomes non-uniform at branches causing irregular intensity distribution
Solution Approach 1:
The patent applies local quality by providing a bulging or arched active deflector surface specifically at the branching portions of the light-guide bar, while the non-branching portions have a different surface configuration. This localized modification addresses the non-uniform light extraction problem at branches without changing the entire light-guide bar design, thereby maintaining cost efficiency while improving light distribution uniformity.
Solution Approach 2:
The patent employs spheroidality by introducing a bulging or arched curvature to the active deflector surface at the branching portions of the light-guide bar. This curved surface configuration helps to redistribute light rays more uniformly as they exit at the branches, eliminating the irregular intensity distribution that would otherwise occur with flat surfaces at branching points.
2Manufacturing precision
If additional LEDs are positioned at distal ends of branches to compensate for non-uniform light extraction, then light distribution uniformity is improved, but the number of LEDs increases and costs rise
Solution Approach 1:
The patent applies self-service by designing the light-guide bar's active deflector surface to automatically correct its own light distribution deficiencies at branching portions. The bulging or arched surface configuration inherently redirects light rays to achieve uniform distribution without requiring external correction elements like additional LEDs, thereby maintaining cost efficiency while achieving uniform light intensity distribution.
3Productivity
If flat longitudinal bands with rectilinear deflector prisms are used on the light-guide bar, then light can be extracted along the bar length, but branching causes shadow effects and non-uniform light distribution
Solution Approach 1:
The patent modifies the deflector prism configuration locally at branching portions by providing a bulging or arched active deflector surface specifically at these locations. This localized adaptation allows light extraction to continue efficiently along the bar length while specifically addressing the shadow effects and non-uniform distribution problems that occur at branching points.
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 configuration ensures uniform backlighting of the ribbon-like portion of the front lenticular half-shell using a single LED source, eliminating shadows and reducing production costs by minimizing the number of LEDs required.
Implementation Method 1
The light then propagates into the photoconductive-material bar as a result of the same physical principles which govern the propagation of light within optical fiber cables.
Implementation Method 2
a multitude of rectilinear, triangular-section deflector prisms, which are appropriately distributed along said flat longitudinal band. These deflector prisms are additionally oriented perpendicularly to the centre line of the flat longitudinal band
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Automotive light (1) comprising a light-guide bar (6) made of photoconductive-material, which is at least partially positioned substantially grazing a corresponding transparent or semitransparent portion of the front lenticular half-shell (3) of the light, and a second light source (7) which is structured so as to emit light when electricity powered, and is arranged inside the rear body (2), close to one end of the light- guide bar (6), so as to direct the light produced inside the body of said light-guide bar (6); the light-guide bar (6) being provided with a longitudinal light-extractor band (8) which extends along the lateral side of the bar, and a multitude of- deflector prisms (9) which have an approximately triangle-shaped cross-section and are conveniently arranged along the longitudinal light-extractor band (8); one or more deflector prisms (9) being shaped so that the active deflector surface (9a) has a bulging/arched profile substantially over, the whole width (w) of the longitudinal band (8).