Total-Internal-Reflection Optical Component for Glare Reduction
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Solution Overview
Problem
Existing optical parts in motor vehicle lighting devices using total internal reflection suffer from stray reflections that cause glare, particularly due to rays passing the cut-off edge and being directly reflected back into the imaging system, leading to increased stray rays and glare risk, while also requiring significant height and thickness.
Innovation Solution
The optical part design incorporates prisms on the first reflection surface to redirect rays away from the exit diopter, utilizing terminal total internal reflection to minimize glare without increasing height, and includes a second reflection surface to manage stray rays, maintaining a thin and efficient beam structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cut-off edge is formed by a sharp angle with the first reflection surface arranged vertically, then the imaging optical system can recover rays passing by the cut-off edge, but the height of the optical part must extend significantly below the level of the cut-off edge
Solution Approach 1:
The invention changes the angular orientation of the first reflection surface from vertical to oblique, introducing a new dimensional parameter (the angle between the first reflection surface and the horizontal plane, specifically 10°-40°) to control ray paths. This angular modification allows the optical system to maintain ray recovery capability while reducing the vertical height requirement of the optical part.
2Length of stationary object
If the angle inside the optical part between the surfaces separated by the cut-off edge is decreased to reduce height, then the optical part height is reduced, but some rays that passed next to the cut-off edge are returned directly to the imaging optical system above the cut-off, increasing stray rays and glare risk
Solution Approach 1:
The invention applies different angular characteristics to different regions of the optical part. The first reflection surface is given a specific oblique angle (10°-40°) relative to the horizontal plane, creating a localized angular property that selectively directs rays. This local angular modification ensures that rays passing near the cut-off edge are reflected at controlled angles, preventing them from reaching the imaging system above the cut-off line and thus reducing stray rays and glare while maintaining compact height.
3Object-generated harmful factors
If the first reflection surface is arranged vertically to prevent stray reflections, then glare risk is reduced, but the optical part height increases significantly
Solution Approach 1:
The invention changes the angular parameter of the first reflection surface from 90° (vertical) to an oblique angle between 10° and 40° relative to the horizontal plane. This parameter modification fundamentally alters the ray reflection geometry, allowing the optical part to achieve effective stray reflection control with a significantly reduced height, thus resolving the contradiction between glare reduction and compact dimensions.
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 effectively reduces glare risk and maintains a thin, efficient beam structure by redirecting stray rays, enhancing beam quality and reducing thickness without increasing height, while ensuring consistent thickness and reducing glare intensity.
Implementation Method 1
The light propagates by total internal reflections on the reflection surfaces of this guide located between the input and output diopters
Implementation Method 2
the first reflection surface comprises at least one facet arranged to reflect towards said second reflection surface said first rays so as to produce said terminal total internal reflection
Implementation Method 3
the second reflection surface comprises at least one facet arranged so as to reflect towards the exit diopter some of these rays reflected by the first reflection surface
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to an optical component having a portion (10) for guiding the light using total internal reflection and comprising: - an input dioptre (2), - a return surface (4), - a cutting edge (6), - a first reflection surface (11) downstream of the cutting edge, - a second reflection surface (21), - an output dioptre (9) which images a row of focal points which are arranged on the cutting edge (6), the return surface returning the light rays (r1, r2) which enter to the row of focal points, first rays (r1) passing beside the cutting edge (6) and reaching the first reflection surface (11), the first reflection surface reflecting these first rays onto the second reflection surface (21), which then reflects them onto the output dioptre (9).