Vehicle Headlight Zero Position Detection Using Optical Absorber
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Solution Overview
Problem
Conventional methods for determining the zero position of a mirror drive motor in vehicle headlamps fail to accurately account for geometric influences such as tolerances and distortions in the optical components, leading to unreliable angular position settings.
Innovation Solution
A headlight design incorporating an absorber surface with a limited opening and a photosensitive sensor to detect the zero position of the light module, where light deflected by the mirror device is absorbed, allowing for reliable calibration of the angular position using the light source itself, and optionally aided by a deflection device to direct the light to the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (driving motor against stop or using mechanical/Hall effect sensors) are used to determine zero position, then the motor position can be determined, but geometric influences such as tolerances in optical component positioning and distortion of the support frame are not recorded, leading to unreliable angular position settings
Solution Approach 1:
The patent replaces mechanical zero position determination methods (motor driving against stop, mechanical sensors, Hall effect sensors) with an optical measurement system. The optical system uses a light source, mirror device, absorber with opening, and photosensitive sensor to detect the zero position by measuring light intensity, thereby eliminating the influence of mechanical tolerances and frame distortions on the zero position accuracy.
Solution Approach 2:
The patent introduces an optical intermediary system consisting of a light source, mirror device, absorber with opening, and photosensitive sensor. This intermediary optical path serves as a mediator to indirectly determine the zero position of the light module, allowing accurate measurement without direct mechanical contact or dependence on the mechanical positioning of optical components.
2Measurement precision
If additional sensors (mechanical or Hall effect) are used to determine zero position, then the motor position can be accurately determined, but the number of components increases and the system becomes more complex
Solution Approach 1:
The patent makes the light source serve multiple functions: it is used both for normal headlight operation and for determining the zero position of the light module. The mirror device is also used in both modes - for light redirection during operation and for directing light through the absorber opening during zero position detection. This multi-functionality eliminates the need for separate dedicated sensors or components.
Solution Approach 2:
The patent merges the zero position detection function with the existing headlight components. The light source, mirror device, absorber with opening, and photosensitive sensor are integrated into the existing headlight structure, combining the operational and measurement functions into a unified system rather than adding separate independent systems.
3Ease of manufacture
If conventional zero position determination methods are used, then the process is simple, but manufacturing tolerances and support frame distortion cause inaccurate angular position settings
Solution Approach 1:
The patent replaces mechanical zero position determination methods with an optical measurement system. The optical system uses a light source, mirror device, absorber with opening, and photosensitive sensor to detect the zero position by measuring light intensity, thereby eliminating the influence of mechanical tolerances and frame distortions on the zero position accuracy.
Solution Approach 2:
The patent changes the measurement parameter from mechanical position (motor angle, sensor position) to optical parameter (light intensity). By measuring the intensity of light passing through the absorber opening, the system determines the zero position based on optical characteristics rather than mechanical dimensions, making the measurement independent of manufacturing tolerances in mechanical components.
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 precise and reliable detection of the zero position, reducing the number of components needed and accounting for manufacturing tolerances, while allowing faster calibration and improved accuracy in headlight range adjustments.
Implementation Method 1
an absorber surface with an opening, wherein light emanating from the light source and deflected by the mirror device onto the absorber surface (instead of out of the headlight) is absorbed there
Implementation Method 2
a photosensitive sensor located behind the aperture in the line of sight of the mirror assembly and adapted to detect the beam of light passing through the aperture
Data Source
Figure 1~4
Figure 5~7
AI summary
In order to determine a zero position of the actuator (14) of a headlight beam adjustment device of a lighting module (10) in a vehicle headlight, light emitted by a light source (1) is directed onto an absorber surface (12). The absorber surface (12) has an opening which light penetrates as a restricted light beam (17). The actuator (14) is used to pivotally adjust the angular position of the lighting module (10), and a photosensitive sensor (15) located behind the absorber surface (12) detects an intensity of the light beam (17) penetrating the opening.