Head-Up Display Luminance Control for Virtual Image Visibility
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Solution Overview
Problem
Conventional head-up display devices adjust the luminance of both virtual images equally based on external light, leading to insufficient visual appeal of the virtual image associated with the actual scene, especially in bright conditions.
Innovation Solution
A head-up display device with a control unit that sets the luminance of the virtual image associated with the actual scene higher than the other virtual image, with the luminance difference increasing as external light intensity increases, ensuring improved visibility in bright environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the luminance of both virtual images is adjusted equally based on external light detection, then the display adapts to ambient lighting conditions, but the visual appeal of the virtual image associated with the actual scene becomes insufficient in bright conditions
Solution Approach 1:
The patent applies local quality by differentiating the luminance adjustment between two types of virtual images. The first virtual image (associated with actual scene) and second virtual image (not associated with actual scene) are adjusted with different luminance values. Specifically, when external light intensity increases, the luminance of the first virtual image is reduced less than or not at all, while the second virtual image luminance is reduced more significantly, creating differentiated local quality in luminance characteristics.
Solution Approach 2:
The patent implements dynamics by making the luminance adjustment strategy adaptive and changeable based on external lighting conditions. The control unit dynamically switches between different luminance adjustment modes: in dark conditions, both images are brightened; in bright conditions, the second image is dimmed more than the first. This dynamic adaptation allows the display system to optimize visual appeal for different environmental conditions.
2Illumination intensity
If the luminance of the first virtual image is increased to improve visibility in bright conditions, then visual appeal improves, but background illumination may occur that could distract the driver
Solution Approach 1:
The patent uses local quality to apply different luminance characteristics to different regions of the display. The first virtual image (associated with actual scene) maintains higher luminance in bright conditions to ensure visibility, while the second virtual image (not associated with actual scene) uses lower luminance to prevent excessive background illumination. This spatial differentiation of luminance quality allows the system to improve first image visibility without causing distracting background glare.
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
Enhances the visual appeal of the virtual image associated with the actual scene by maintaining adequate luminance in bright conditions while preventing background illumination that could distract the driver.
Implementation Method 1
a HUD device described in Patent Document 2 includes an optical sensor for detecting a luminance of external light
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
Provided are a head-up display device and an onboard display system capable of improving the visual appeal of a virtual image, from among multiple virtual images, that is associated with an actual scene. A HUD device displays a first virtual image V1, which is associated with an actual scene, and a second virtual image V2, which is not associated with the actual scene. The HUD device is equipped with a HUD control unit that sets the luminance G1 of the first virtual image V1 to be higher than the luminance G2 of the second virtual image V2 by a luminance difference X, and sets the luminance difference X to be larger as a light control value I2 increases, such value being determined on the basis of the intensity of external light.