Vehicular Lamp Adaptive Light Distribution Control
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Solution Overview
Problem
The existing adaptive driving beam (ADB) technologies, such as the scanning type, face challenges in controlling light distribution modes due to the complexity of synchronizing PWM dimming with the periodic motion of the reflector, requiring high-priced microcomputers or CPUs, making it difficult to implement effectively.
Innovation Solution
A vehicular lamp design that includes a light source unit with multiple light emitting units connected in series, a scanning optical system, and a lighting circuit with constant current drivers and bypass switches, allowing for independent control of light distribution modes by adjusting drive current and bypass switch timing, simplifying the control process and enabling efficient switching between modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PWM dimming is used to control brightness in the scanning type, then brightness control range is improved, but control complexity increases requiring high-priced microcomputers
Solution Approach 1:
The light emitting units are divided into multiple channels with series-connected LEDs in each channel. Each channel is controlled independently by separate constant current drivers, allowing brightness control without complex PWM synchronization. This segmentation enables simple ON/OFF control per channel while achieving wide brightness adjustment through channel combination.
Solution Approach 2:
Instead of using PWM dimming to control brightness (the conventional approach), the patent inverts the approach by using constant current control with bypass switches. The brightness is controlled by selecting which channels are active and how many LEDs within channels are bypassed, rather than varying duty cycle. This inversion simplifies the control logic while maintaining brightness control capability.
2Reliability
If the number of light emitting units in each channel is increased, then current variation is reduced, but voltage requirement increases
Solution Approach 1:
The patent dynamically adjusts the series/parallel configuration of LEDs within channels based on operating conditions. Bypass switches allow flexible reconfiguration of electrical connections to optimize performance. When high current stability is needed, more LEDs are connected in series; when voltage headroom is limited, parallel paths are activated through bypass switches, enabling adaptive optimization of the voltage-current tradeoff.
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
Enables the vehicular lamp to switch multiple light distribution modes adaptively, reducing glare and improving visibility while simplifying the design of constant current drivers, allowing for effective control of light distribution patterns without the need for high-priced microcomputers.
Implementation Method 1
a light source unit including a plurality of light emitting units that are classified into a plurality of channels
Implementation Method 2
a scanning optical system configured to receive emitted light of the light source unit and scan the emitted light in front of the vehicle by repeating a predetermined periodic motion
Data Source
AI summary
A vehicular lamp is provided with a plurality of light emitting units and configured to independently control ON/OFF of the light emitting units. The plurality of light emitting units are disposed so that a desired light distribution is formed by overlapping scanning of illumination spots formed on a virtual screen by emitted lights thereof. The plurality of light emitting units are divided in a plurality of channels, the same direct drive current is supplied to at least one light emitting unit of all of the light emitting units included in the same channel, and the direct drive current is constantly maintained during a scanning period. The current amount of drive current for each channel is set in accordance with a light distribution mode, and ON/OFF of each light emitting unit is switched at a predetermined timing determined in accordance with the light distribution mode during a scanning period.