Scanning Lighting Circuit for Delay-Corrected ADB Light Distribution
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Solution Overview
Problem
Existing automotive lamps with adaptive driving beam (ADB) technology face issues such as unintended delays in light source activation or deactivation, noise contamination in pulse signals, and motor lock states, leading to inaccurate light distribution patterns and potential glare or reduced visibility.
Innovation Solution
A lighting circuit that measures the period of a pulse signal synchronized with motor rotation, generates a dimming signal for precise light control, and includes a motor control unit with a lock protection function to prevent motor lock states, ensuring accurate light distribution and reduced noise effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a lighting circuit controls the light source to turn on/off based on a pulse signal synchronized with motor rotation, then the light distribution pattern accuracy is improved, but unintended delays occur in light source activation or deactivation due to individual circuit variation and temperature fluctuation
Solution Approach 1:
The patent measures the delay time between the pulse signal and the actual light source activation in advance, then uses this measured delay information to pre-correct the light source control timing. By adding the measured delay time to the control signal timing beforehand, the system compensates for the unintended delays caused by circuit variations and temperature fluctuations, ensuring accurate light distribution patterns.
2Manufacturing precision
If the lighting circuit uses a pulse signal synchronized with motor rotation to control light source timing, then the light distribution accuracy is improved, but noise contamination in the pulse signal causes erroneous timing control
Solution Approach 1:
The patent employs a feedback mechanism where the actual light source activation timing is monitored and compared with the expected timing based on the pulse signal. The measured delay time serves as feedback information that is used to adjust and correct the control timing in subsequent cycles, thereby compensating for noise-induced errors and maintaining accurate light distribution patterns despite pulse signal contamination.
3Productivity
If the motor operates continuously to rotate the scanning light source, then the ADB function is maintained, but the motor may enter a lock state causing abnormal heat generation and reliability issues
Solution Approach 1:
The patent implements a feedback-based motor monitoring system that detects the motor's operational state by monitoring its rotation performance. When the motor enters a lock state, the system detects this abnormal condition through feedback signals and automatically stops the motor to prevent excessive heat generation and damage. After a predetermined period, the system attempts to restart the motor, thereby maintaining ADB function continuity while preventing reliability issues from motor lock states.
Data Source
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AI summary
A scanning light source 100 includes a semiconductor light source 110 and a motor 120, and scans output light of the semiconductor light source 110 in front of a lamp according to the movement of the motor 120. A constant current driver 220 supplies a driving current ILED to the semiconductor light source 110 according to a light source control signal S6. A light source control signal generator 210 generates the light source control signal S6 so as to obtain a light distribution pattern that corresponds to light distribution instruction data. A delay time measurement device 260 measures the delay time τ required for the transition of the on/off states of the semiconductor light source 110 from the change of the light source control signal S6.