Light Guide PWM Ramp Control for Uniform Scrolling Illumination
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Solution Overview
Problem
Existing methods for controlling the turn-on of light sources in motor-vehicle lighting produce a relatively coarse scrolling effect with non-uniform illumination, leading to spots or segments that do not meet lighting regulations.
Innovation Solution
A method using pulse-width modulation with distinct control ramps to gradually turn on light sources, improving the refinement and uniformity of the scrolling illumination beam, while reducing the number of light sources required and simplifying the electronic design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional turn-on control with single control ramp is used, then the structure is simple, but the scrolling effect is coarse and illumination is non-uniform
Solution Approach 1:
The turn-on control process is segmented into multiple phases with distinct control ramps. The first control ramp operates during an initial phase to establish baseline illumination, while the second control ramp operates during a subsequent phase to achieve maximum illumination. This temporal segmentation of the control process enables refined illumination uniformity without requiring additional hardware components.
Solution Approach 2:
The control method employs dynamic adjustment of illumination intensity through time-varying control ramps. The first and second control ramps have different slopes, creating a dynamic illumination profile that evolves over time. This dynamic control approach produces a refined scrolling effect with uniform illumination distribution along the light guide, eliminating the coarse appearance of conventional static control methods.
2Manufacturing precision
If multiple light sources are used to improve scrolling effect, then the illumination uniformity improves, but the cost and device complexity increase
Solution Approach 1:
The invention employs periodic pulse-width modulation (PWM) signals to control the light source intensity during turn-on. By applying periodic control pulses with varying duty cycles according to the distinct control ramps, the method achieves refined scrolling illumination effects using a single light source, thereby avoiding the cost and complexity increases associated with multiple light sources.
Solution Approach 2:
The control method changes the illumination parameters (intensity, duration, timing) through distinct control ramps applied during different phases. By varying these parameters dynamically, the system achieves refined scrolling effects and uniform illumination distribution without requiring additional light sources, thus maintaining simple device architecture while improving illumination quality.
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 method enhances the refinement and uniformity of the scrolling illumination beam, reduces costs, and simplifies the electronic design, while maintaining compliance with motor-vehicle lighting regulations.
Implementation Method 1
any optical part capable of guiding light by total internal reflection of this light, for example from an entrance region to an exit region
Data Source
AI summary
The invention relates to a method for controlling the illumination of at least one light source arranged at an end of at least one at least partially transparent or translucent light guide, the method being implemented by a driver device for driving the light source. According to the invention, the driver device is configured to control the illumination of the light source by means of pulse-width modulation and the method includes a first phase in which the illumination of the light source is controlled according to a first control ramp until a first level of intermediate lighting of the light source is reached and a second phase in which the illumination of the light source is controlled according to a second control ramp until a second level of lighting of the light source is reached, the slopes of the first and second control ramps being separate.