Vehicle Headlight Waveguide for Thin Directional Beam Control
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Solution Overview
Problem
Existing illumination systems for vehicles, such as headlights, struggle to provide efficient and controlled narrow angle illumination, which is essential for safe and effective road lighting.
Innovation Solution
A directional illumination device featuring an array of light sources and a waveguide with a reflective end and guide surfaces, where the light sources input light into the waveguide at different positions, and the waveguide extracts and directs the light to exit in specific output illumination directions based on the input positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional focusing optics are used to provide narrow directional light output, then illumination control is achieved, but device complexity and cost increase
Solution Approach 1:
The illumination device is segmented into multiple independent light sources arranged in an array, each corresponding to a specific lateral position. This segmentation allows independent control of illumination zones without requiring complex optical elements for each light source, thereby achieving illumination control while reducing overall device complexity
Solution Approach 2:
The patent changes the operational parameters by controlling which light sources are activated based on detected environmental conditions (such as oncoming vehicles or pedestrians). This parameter-based control approach replaces complex mechanical or optical switching mechanisms, achieving adaptive illumination control with simpler device architecture
2Measurement precision
If multiple optical elements are used to achieve precise beam direction control, then illumination precision improves, but manufacturing cost increases
Solution Approach 1:
The waveguide structure itself serves the dual function of guiding light from multiple sources and extracting light at specific positions. The waveguide's inherent optical properties (total internal reflection, evanescent wave coupling) automatically provide the necessary beam direction control without requiring additional optical elements, thereby achieving precise beam control while simplifying manufacturing
Solution Approach 2:
The waveguide performs multiple functions simultaneously: it acts as a light transmission medium, a beam directing element, and an extraction mechanism. This multi-functionality eliminates the need for separate optical components for each function, reducing manufacturing complexity and cost while maintaining precise beam direction control
3Volume of moving object
If a compact optical structure is used, then device size is reduced, but light extraction efficiency decreases
Solution Approach 1:
The patent transitions from traditional planar optical structures to a three-dimensional waveguide configuration. Light is coupled into the waveguide at the input surface and propagates through the bulk of the waveguide before extraction occurs at the lateral surface. This dimensional transition allows efficient light extraction in a compact volume by utilizing the waveguide's thickness dimension for light propagation and the lateral dimension for extraction
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 achieves high efficiency in directing light into precise illumination cones with high beam shape fidelity, providing a thin and cost-effective optical structure for vehicle external lights.
Implementation Method 1
the first guide surface is arranged to guide light by total internal reflection
Implementation Method 2
the waveguide is arranged to guide input light from the input surface to the reflective end and back along the waveguide after reflection at the reflective end
Implementation Method 3
the second guide surface may comprise: at least one light extraction feature, arranged to extract input light by deflecting the input light as it is guided back along the waveguide
Data Source
AI summary
A directional illumination device for a vehicle external light comprises an array of light sources and an imaging waveguide comprising an input surface and a reflective end. Opposed guide surfaces are arranged to guide input light from the input surface to the reflective end and back along the waveguide after reflection at the reflective end, the waveguide being arranged to extract input light as it is guided back along the waveguide after reflection and to cause the extracted light to exit through the first guide surface. The reflective end has positive optical power in the direction laterally across the waveguide and the waveguide is arranged to direct the extracted light in respective output illumination directions distributed in a lateral direction in dependence on the input positions of the light sources in the direction laterally across the waveguide. A thin, high brightness and high efficiency controllable directional vehicle headlight is provided.