Vehicular Head-Up Display Position Adjustment for Light Visibility
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Solution Overview
Problem
Vehicular head-up displays face challenges in ensuring visibility during strong external light conditions, such as daytime on clear days, where the influence of external light overwhelms the virtual image, making it difficult for drivers to recognize the displayed information without needing to move their viewpoint or focus their eyes.
Innovation Solution
A vehicular display device that automatically adjusts the projection position of the virtual image based on external light intensity, switching between a position less influenced by light and one more influenced, ensuring visibility while minimizing driver movement and focusing needs, using a control circuit with an illuminance sensor and electric motor to adjust the light path via a mirror and combiner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the virtual image is projected to the front windshield to enable simultaneous recognition of scenery and display, then the head-up display function is achieved, but visibility is reduced under strong external light conditions
Solution Approach 1:
The patent implements a dynamic projection position adjustment mechanism that automatically changes the virtual image projection position based on external light conditions. The control unit detects illuminance levels and adjusts the projection position between a first position (less influenced by external light) and a second position (more influenced by external light), making the system adaptive to varying environmental conditions rather than static.
Solution Approach 2:
The patent changes the spatial parameter of the virtual image projection position based on external light intensity. By switching between different projection positions (first position below the windshield and second position on the windshield), the system adjusts the optical parameters to maintain visibility under varying illuminance conditions, directly addressing the contradiction between visibility and external light influence.
2Object-affected harmful factors
If the virtual image projection position is changed to avoid external light, then visibility under strong light is improved, but the driver needs to move viewpoint or focus eyes
Solution Approach 1:
The patent creates different local display regions with different characteristics. The first projection position (below the windshield) provides a display region less influenced by external light, while the second position (on the windshield) provides a region that integrates with the scenery view. The control unit selectively activates the appropriate local region based on external light conditions, ensuring optimal visibility without requiring driver adaptation.
3Illumination intensity
If the light intensity of the virtual image is increased to overcome external light, then visibility is improved, but the external light influence remains too strong
Solution Approach 1:
The patent extracts the virtual image from the high-external-light region (windshield area) and relocates it to a low-external-light region (below the windshield) when external light intensity is high. This spatial extraction separates the display from the harmful external light environment, making the display visibility independent of external light intensity increases.
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 device maintains sufficient visibility even in high external light conditions, reducing the need for driver viewpoint movement and eye focusing, by automatically adjusting the virtual image projection to a position below the windshield where external light influence is minimized.
Implementation Method 1
an illuminance sensor that detects an intensity of external light
Implementation Method 2
a light projection unit that reflects light containing the visible information displayed on the display unit by a predetermined light reflection member to project the light to a predetermined observation region
Data Source
AI summary
A vehicular display device includes a display unit that displays visible information, a light projection unit that includes a reflection member which reflects light containing the visible information displayed on the display unit and projects the reflected light to a predetermined observation region to display the visible information as a virtual image, a light path adjustment mechanism that switches an imaging position of the virtual image between at least two positions, an illuminance detection unit that detects an intensity of external light affecting visibility of the virtual image, and an imaging position control unit that controls the light path adjustment mechanism depending upon the illuminance and changes the imaging position to a first position, at which the virtual image is less influenced by the external light, or to a second position, at which the virtual image is easily influenced by the external light.