Revolutionizing Automotive HUDs with Luminit’s Advanced Optical Solutions
Adapted from the paper Windshield holographic film HUDs transform EV cost, safety and delight! written and presented at VDI 2024 by Jonathan Waldern
The Future of Automotive Displays: AR and Panoramic HUDs
For decades, automotive consoles designs have remained similar, with gauges and dials to show information or control critical functions. Having to look down and away from the windshield draws the eye and attention away from the road; situations on the road can change in a split second, so the less “head down” time, the better for safety. Although the introduction of in-dash displays has consolidated some functions on a typical console and added ease in tasks like navigation, these still require the driver to look away from the road and thus are largely just a cosmetic change.
But, as stated in a recent Economist® article: “Everything about car making is changing at once.” As BYD and Tesla wrestle for dominance, China’s pushes a technology-driven, rapid time-to-market, hurtling toward a previously unthinkable two-year model cycle. This acceleration demands a reduction in complexity for agile assembly and innovation in interior technology, so the market will be inundated with changes. But how to catch the eyes of consumers seeking novelty in an increasingly diversified market?
—by swapping a complex console full of dials and small displays with an under-dash projector that works on the windshield to replace traditional auto instrument clusters with clearer, more efficient head up displays (HUDs).
With everything integrated into the windshield, real-time information such as navigation or object sensing can be displayed without being intrusive, and drivers do not have to take their eyes off the road. Thus, manufacturers can simultaneously simplify assembly and meet consumer desire for innovation and increased safety.
Automotive makers are already making moves toward mass implementation, as HUDs are increasingly appearing in internal combustion engine (ICE) vehicles and electric vehicles (EVs), thanks to their safety, elegance, and cost savings. For example, BMW’s Panoramic Vision display uses the entire lower width of the windshield (known as the “Frit” area) as a screen to project critical information across, fusing reality and virtual elements.
Luminit Inc. is developing and bringing to market a panoramic HUD that goes a step further by not only integrating an electrochromic film in this frit area for ambient light control, but also its holographic HUD film laminated within the windshield simultaneously. The result is a highly efficient HUD instrument display that dynamically adjusts from transparent to opaque. Luminit has used Covestro photopolymer film for its holographic HUD which has been successfully laminated and tested by Luminit and partners in the windshield. This lamination has also passed independent lifetime tests for durability, environmental resistance and optical quality by Carlex, a leading automotive windshield manufacturer partnering FORD, at the Vehicle Display Conference 2024, in Detroit. This innovative technology reduces weight, increases reliability, and provides a cost-effective solution to replacing traditional dashboard LCD panels with immersive HUD experiences.
Luminit’s Holographic Optical Platform: A Game Changer for HUDs
Conventional refractive optics composed of lenses and mirrors are bulky, heavy, and costly to manufacture and install in precision assemblies. In an automotive HUD application, these optics are also subject to broad temperature variation, acute vibration, yet expected to have a long service life. Hence, conventional automotive HUDs, although much desired by drivers for both eyes-on-road safety and convenience, have remained an expensive accessory confined to top range models.
Luminit has developed holographic wide-angle film technology that enables HUDs with wider field-of-views and driver eye boxes. An entire assembly can be consolidated into one optic which provides illumination homogenization, image path re-direction, image formation, and laser de-speckling. Surface relief and volume Bragg grating structures allow optical angle control, including beam shaping, with either high transmission or reflection. By eliminating issues like stray light, color shifts, and chromatic aberration, Luminit’s diffusers offer an ideal solution for HUDs in modern vehicles. When laminated into the windshield, with over 90% transparency and 80% image reflectivity, this technology achieves sharp high contrast display even in the brightest ambient conditions.
Benefits of AR and In-Plane HUDs for Modern Vehicles
Luminit currently offers two key HUD configurations: AR(augmented reality)-HUD and IP(in-plane)-HUD. AR-HUDs provide a bright virtual image with a wide field of view, projecting important navigational information directly into the driver’s line of sight. IP-HUD, on the other hand, displays infotainment content on the windshield for both the driver and passengers, offering clarity comparable to a monitor screen. Both type of display can exist alongside one another, offering the consumer and appropriate mix of both 2D and 3D.
Luminit films are laminated between windshield layers, ensuring long lifetime and temperature reliability. The AR-HUD features a laser projector that eliminates speckle using Luminit’s image forming HUD diffuser to ensure clear and legible visuals even in bright sunlight or while wearing polarized sunglasses.
Optimizing Automotive HUDs with Luminit’s Transparent Films and Holographic Technology
Advanced Light Shaping for Automotive HUD Performance
Luminit’s Light Shaping Diffuser® (LSD®) technology optimizes the light beams emitted by HUD projectors to enhance image quality and reduce distortions. By using micro-optics, Luminit can shape light into circular or rectangular patterns with high transmission efficiency. The resulting display has minimal backscatter, ensuring sharp and clear images across the entire windshield area.
Luminit’s Direction Turning Film (DTF) manipulates the light path to ensure that the projected image aligns with the driver’s line of sight. This technology supports off-axis projector locations, critical for maximizing dashboard space in electric vehicles.
Expanding Visibility and Reducing Complexity
Luminit’s HUD technology provides a larger, brighter display and a wider field of view, giving auto designers more freedom to integrate advanced features into vehicle interiors. The company’s proprietary roll-to-roll manufacturing lines allow for large-area exposures and ensure high precision in optical functions like illumination, image redirection, and laser de-speckling.
Integrating Electrochromic Films for Improved Visibility
Luminit’s panoramic HUD will integrate electrochromic films in the lower “frit” area of the windshield, which dynamically adjust from transparent to opaque based on ambient light. This advanced technology provides clear visibility in all lighting conditions and enhances driving safety. The holographic diffuser films used in Luminit’s HUDs offer two categories of projection: AR infinity projection and in-plane projection (IP), both optimized for automotive environments.
Luminit’s integration of electrochromic films into HUDs further enhances visibility in various driving conditions. These films dynamically adjust the level of light entering the vehicle, enabling HUDs to maintain optimal display clarity in bright sunlight or low-light environments. Electrochromic film is a low-power solution that adapts to environmental changes without compromising on performance.
Unlike other light attenuating films, Luminit’s electrochromic films block only 2-4% of external light and can transition from light to dark in just six seconds. This fast adaptation ensures that drivers always have a clear view of both the HUD display and the road ahead.
The integration of these cutting-edge materials results in a dynamic HUD display that adapts to both bright daylight and low-light driving conditions, ensuring optimal visibility and reducing the strain on the driver’s eyes.
Driving the Future with Luminit’s Cutting-Edge HUD Technology
Transparent in-windshield automotive head-up displays provide an integrated solution to improve navigation and safety. For example, LiDAR sensors attached to the car can monitor the road in real-time, which can be combined with GPS and traffic information to provide visual prompts not only for navigation but also to warn drivers about changes in oncoming traffic or pedestrians, obstructions, or vehicles on the periphery of their vision and in blind spots. Furthermore, information about the car such as current driving speed can be viewed more conveniently, keeping drivers cognizant; nowadays, mobile app navigation services show speed limits and this information can be integrated into the alerts given on the transparent display—of course, this is only one example of the possibilities offered by having transparent head-up displays.
HUD technology, while traditionally associated with automotive applications, is poised to play a significant role in avionics, marine, trucking, construction, and farm equipment industries as well. In aviation, HUD systems are already proven in cockpits to enhance pilot visibility and situational awareness, particularly during takeoff, landing, and low-visibility conditions. As HUD technology evolves, incorporating Artificial Intelligence (AI) technology alongside augmented reality (AR), next-generation HUDs will deliver more intuitive flight data, reduce pilot workload, and improve overall flight safety. Similarly, in marine applications, AR-HUDs integrated into the navigational systems of ships, yachts, and boats will provide enhanced real-time data on sea conditions, navigation routes, and warnings of potential hazards, all while ensuring that operators can maintain constant visibility of the surrounding environment. As demand for safer, more efficient transport grows in these sectors, HUD systems offer the potential to revolutionize both avionics and marine navigation with panoramic, transparent displays that seamlessly integrate critical information without distracting from the external view.
Luminit’s patented holographic optical solutions enable the creation of panoramic windshield HUDs, and having optical design, R&D, proof-of-concept demonstration, and manufacturing vertical integration means faster time-to-market. In this race toward the future of transportation development, it pays to stay a step ahead of the competition.