Electro-optic Assembly for Vehicle HUD with Refractive Index Control
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Solution Overview
Problem
Current vehicle heads-up displays (HUDs) face challenges in maintaining adequate contrast and brightness in varying lighting conditions, particularly in bright sunny days, where the contrast between the HUD and external lighting can be low, and increasing brightness leads to increased power consumption and heat generation, making it difficult to provide reasonable visibility.
Innovation Solution
An electro-optic assembly with arcuate substrates and an electro-optic medium is used, where the substrates are positioned with a seal between them, and an electro-optic medium with a refractive index greater than 1.2 is placed in a cavity, allowing for controlled light transmittance and reflection of incident light from a projector to enhance visibility and reduce unwanted reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If brightness is increased to improve visibility in bright conditions, then visibility is improved, but power consumption and heat generation increase
Solution Approach 1:
The patent applies parameter changes by varying the refractive index of the electro-optic medium (greater than 1.2) and adjusting the thickness and properties of anti-reflective coatings to optimize light transmission. This allows the system to achieve adequate visibility without excessive brightness, thereby reducing power consumption and heat generation while maintaining acceptable contrast ratios in bright environmental conditions.
Solution Approach 2:
The electro-optic medium with refractive index greater than 1.2 acts as an intermediary between the projector and the external environment. It mediates the light transmission properties, enabling controlled adjustment of light passage to achieve visibility without requiring high brightness levels that would increase power consumption and heat generation.
2Illumination intensity
If brightness is increased to improve visibility in bright conditions, then visibility is improved, but heat generation increases
Solution Approach 1:
The patent utilizes parameter changes in the electro-optic medium's refractive index (greater than 1.2) and coating properties to optimize light transmission efficiency. This allows the system to achieve adequate visibility without excessive brightness, thereby reducing heat generation while maintaining acceptable contrast ratios in bright environmental conditions.
Solution Approach 2:
The electro-optic medium with refractive index greater than 1.2 serves as an intermediary that controls light transmission properties. It enables the system to achieve visibility without requiring high brightness levels that would generate excessive heat, thus managing thermal output while maintaining display quality.
3Object-affected harmful factors
If anti-reflective coating is applied to reduce reflections, then unwanted reflections are minimized, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by implementing anti-reflective coatings with specific refractive indices (greater than 1.2) at particular locations and interfaces within the optical assembly. Rather than uniformly treating all surfaces, the coating is strategically applied to specific optical elements where reflection control is most critical, thereby reducing unwanted reflections while managing manufacturing complexity.
Solution Approach 2:
The patent employs composite materials by combining the electro-optic medium with refractive index greater than 1.2 with anti-reflective coatings of specific properties. This composite structure achieves reduced unwanted reflections through the synergistic effect of the medium's optical properties and the coating's reflection control, balancing performance improvement with manufacturing feasibility.
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 improves contrast and visibility by varying light transmittance based on environmental conditions, reducing power consumption and heat generation, while minimizing double imaging and glare, thus providing effective display of vehicle-related information in bright conditions.
Implementation Method 1
The light transmittance of the electro-optic assembly is controlled by varying a potential between the coatings on the second and third surfaces
Implementation Method 2
The first surface is coated with an anti-reflective coating, including less than 1% reflectance
Implementation Method 3
The second surface is coated with a reflective coating... The second surface receives and reflects incident light projected from a projector
Implementation Method 4
The third surface is coated with a light transmissive and conductive coating
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
An electro-optic assembly for use in a vehicle having a windshield is provided and includes a first arcuate substrate having a first surface with an anti-reflective coating and a second surface. A second arcuate substrate includes a third surface and a fourth surface with an anti-reflective coating. The first and second substrates are positioned such that the second and third surfaces are at least 0.1 mm apart. A seal is disposed between the first and second substrates and located substantially about a periphery of the electro-optic assembly. An electro-optic medium is positioned in a cavity defined by the first substrate, the second substrate, and the seal, the electro-optic medium including a refractive index greater than 1.2. The second surface is configured to receive and reflect incident light projected from a projector, thereby displaying information that appears to be displayed forward of the windshield.