Vehicle HUD Combiner Screen with Electro-Optic Layer
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Solution Overview
Problem
Heads up displays in vehicles often experience undesirable double imaging due to reflectance off surfaces, which affects the clarity and visibility of information overlay on ambient light.
Innovation Solution
A heads up display system with a combiner screen comprising multiple transparent substrates and an electro-optic material, incorporating a transflective layer and a reflective polarizer, which allows for high reflectance and adjustable transmittance to enhance image clarity and visibility, while minimizing double imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple transparent substrate is used for the combiner screen, then the device complexity is reduced, but double imaging occurs due to reflectance off surfaces
Solution Approach 1:
The combiner screen is divided into multiple transparent substrates (first, second, and third substrates) with specific optical coatings on each surface. This segmentation allows different surfaces to have different reflectance and transmittance properties, enabling control over double imaging while maintaining overall system functionality.
Solution Approach 2:
An electro-optic material is introduced as an intermediary between the first and second substrates. This intermediary layer enables dynamic control of light transmission and reflection properties, allowing the system to adjust transmittance levels and minimize double imaging effects under different operating conditions.
2Illumination intensity
If a transflective layer is added to increase reflectance, then visibility of projected information is improved, but the structure becomes more complex
Solution Approach 1:
The transflective layer is integrated into the existing multi-substrate structure by positioning it between the first and sixth surfaces. This merging approach combines the reflective and transmissive functions within the overall combiner screen assembly, achieving enhanced visibility without requiring a completely separate system.
Solution Approach 2:
The combiner screen structure is designed to perform multiple functions simultaneously: the first substrate provides structural support and partial reflection, the electro-optic material enables dynamic transmittance control, and the transflective layer enhances reflection of projected light. This multi-functionality achieves high reflectance while maintaining a integrated structure.
3Object-generated harmful factors
If multiple transparent substrates are used to control reflectance, then double imaging is minimized, but the device complexity increases
Solution Approach 1:
Different surfaces of the transparent substrates are assigned different optical properties through selective coating. For example, the outer surfaces may have anti-reflective coatings while internal surfaces have reflective coatings. This local differentiation of optical quality allows precise control over reflection and transmission at each interface, minimizing double imaging.
Solution Approach 2:
The combiner screen employs a composite structure combining multiple transparent substrates with different optical characteristics and electro-optic materials. This composite approach allows the system to achieve superior optical performance by combining materials with complementary properties, managing reflectance and minimizing double imaging effects.
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 system provides improved contrast and visibility of information overlay on ambient light, reducing double imaging and glare, and is operable at various transmittance levels for different lighting conditions, enhancing driver experience.
Implementation Method 1
An electro-optic material is positioned between the first substrate and the second substrate
Implementation Method 2
A reflective polarizer is positioned between the sixth and first surfaces
Implementation Method 3
A transflective layer is positioned between the first and sixth surfaces
Data Source
AI summary
A heads up display system of a vehicle includes a combiner screen having a first substantially transparent substrate defining a first surface and a second surface, a second substantially transparent substrate defining a third surface and a fourth surface. A primary seal is disposed between the first and second substrates. The seal and the first and second substrates define a cavity therebetween. An electro-optic material is positioned within the cavity and a transflective layer having a multilayer polymeric film positioned on one of the first and second surfaces, and a projector for projecting light having a first polarization toward the first surface of the first substrate.