Head-Up Display White-Light Tuning Against Headlamp Overlap
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Solution Overview
Problem
The visibility of information displayed by a head-up display device is compromised when its image light overlaps with the irradiation light of a headlamp, especially when both use white light, making it difficult for drivers to recognize the virtual images superimposed on the landscape.
Innovation Solution
A head-up display device with a light source that emits white light with adjustable correlated color temperature, synchronized with the headlamp's light, to create a distinct color tone difference, ensuring the image light is easily recognizable while maintaining the visibility of the headlamp's irradiation light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the head-up display device uses white light for image light to match the headlamp's irradiation light, then the overall visibility is improved, but the image light becomes difficult to distinguish from the irradiation light
Solution Approach 1:
The patent applies color temperature adjustment to differentiate the image light from the irradiation light. The control unit adjusts the color temperature of the white light source based on the detected color temperature of the headlamp's irradiation light, creating a distinguishable color tone difference while both remain in the white light range. This allows the image light to be visible against the landscape while maintaining distinguishability from the headlamp light.
2Loss of information
If the correlated color temperature of image light is adjusted to be different from irradiation light by 1000K or more, then the distinguishability is improved, but the natural appearance of white light may be compromised
Solution Approach 1:
The patent changes the color temperature parameter of the white light source dynamically. By adjusting the correlated color temperature to be at least 1000K different from the irradiation light while keeping it within the white light range (typically 2000K-10000K), the system achieves distinguishability without deviating too far from the natural appearance of white light. The control unit implements this parameter adjustment based on real-time detection of the headlamp's color temperature.
3Device complexity
If the head-up display device uses a fixed color temperature light source, then the device complexity is reduced, but the adaptability to different headlamp conditions is worsened
Solution Approach 1:
The patent implements a dynamic light source control system where the color temperature of the white light source is adjusted in real-time based on the detected color temperature of the headlamp's irradiation light. This dynamic adaptation allows the head-up display to work effectively with different types of headlamps (halogen, LED, HID) without requiring multiple fixed-color-temperature light sources, thus maintaining reasonable device complexity while achieving high adaptability.
Solution Approach 2:
The system employs a feedback mechanism where the control unit detects the color temperature of the irradiation light and uses this information to adjust the color temperature of the image light source accordingly. This closed-loop control ensures that the image light remains distinguishable from the irradiation light under various operating conditions while maintaining a relatively simple device architecture through intelligent control algorithms.
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 enhances the visibility of the head-up display information by creating a clear color tone difference between the image light and the headlamp's light, reducing eye fatigue and ensuring both are visible effectively.
Implementation Method 1
a light source configured to emit white light whose correlated color temperature is changeable
Data Source
AI summary
A head-up display device is provided in a vehicle together with a headlamp. The head-up display device includes a light source, a control unit, and a projection unit. The light source emits white light whose correlated color temperature is changeable. The control unit adjusts the correlated color temperature of the white light emitted from the light source. The projection unit forms image light by the white light emitted from the light source. The projection unit projects the image light onto a projection target member disposed in front of a driver of the vehicle, thereby displaying a virtual image superimposed on a landscape for the driver. The control unit adjusts the correlated color temperature of the white light emitted from the light source in accordance with a correlated color temperature of irradiation light emitted from the headlamp.