Display Light Guide Layout for Stable Ambient Brightness Sensing
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Solution Overview
Problem
Head-up displays in vehicles face challenges in maintaining optimal brightness adaptation to varying ambient light conditions without dazzling the driver, particularly due to the placement of light sensors which can degrade the exterior appearance and allow foreign particles entry, and are prone to parasitic variations in brightness from secondary light radiation sources.
Innovation Solution
Incorporating a light guide within the display housing to collect and direct external light radiation to the light sensor, ensuring it is positioned to receive light from the direction of the virtual image formation, thus maintaining a smooth exterior appearance, preventing foreign particle entry, and minimizing the impact of secondary light variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the light sensor is placed inside the display housing, then the electrical and mechanical connection constraints of the sensor are satisfied, but the interior of the display case becomes visible to users, degrading the exterior appearance
Solution Approach 1:
A light guide is introduced as an intermediary component between the external environment and the light sensor inside the housing. The light guide's entry face is positioned at the housing opening, allowing light to enter the housing and reach the sensor while the light guide itself masks the interior components from external view, thus resolving the contradiction between sensor accessibility and aesthetic appearance
2Reliability
If an opening is made in the display case for light sensor access, then external light radiation can reach the sensor, but foreign bodies such as dust particles can enter the display housing
Solution Approach 1:
The light guide serves as a protective intermediary structure that channels external light to the sensor through a controlled path. The light guide's structure allows light transmission while physically blocking foreign bodies like dust particles from entering the housing interior, thus maintaining both sensing functionality and protection against contaminants
3Measurement precision
If the light sensor receives light from all directions, then it can measure ambient brightness, but it also captures secondary light radiation causing parasitic variations in image brightness
Solution Approach 1:
The light guide is designed with specific geometric properties that create directional selectivity. By controlling the orientation and shape of the light guide's entry face and internal structure, it preferentially collects light from the direction of the virtual image formation while rejecting light from other directions, thus achieving both adequate ambient light measurement and immunity from parasitic light variations
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 light guide effectively collects and measures light radiation from the intended direction, allowing for precise brightness adjustment of the virtual image, enhancing visibility and reducing parasitic fluctuations, while maintaining a unified and dust-proof exterior appearance.
Implementation Method 1
a light guide located inside the display housing, having an entry face and shaped to collect at the level of its face input light radiation coming from outside the display case, and to guide said light radiation to said sensor
Data Source
Figure 1~2
AI summary
The invention relates to a display (1) comprising - a casing (10), - an image generation unit (20), and - a light sensor (30), disposed in the interior (INT) of said casing (10), suitable for delivering a signal representative of a light intensity received by same, the display (1) being adapted such that the luminosity of an image generated by the image generation unit (20) is controlled as a function of said signal. According to the invention, the display (1) further comprises a light guide (50) situated in the interior (INT) of the casing (10) of the display (1), having an inlet face (51) and being shaped to collect at the input face (51) of same a light ray coming from outside the casing (10) of the display, and for guiding said light ray to said sensor (30).