ZEISS holographic windshield display: Reconciling infotainment demands with design freedom

In the rapidly evolving landscape of automotive design, a significant conflict emerges between consumer expectations and the aspirations of interior designers. On one hand, today's consumers are increasingly demanding innovative features and enhanced functionalities in their in-car display and entertainment systems. This often results in the addition of multiple screens and bulky optical components that encroach upon the limited space available within vehicle interiors. Conversely, designers strive for a sleek and harmonious aesthetic that prioritizes freedom of design and the seamless integration of technology into the overall interior environment. This dichotomy presents a challenge. How to balance the desire for cutting edge technology with the need for an elegant and cohesive design that enhances the driving experience without overwhelming it.

ZEISS' cutting-edge Holographic Windshield Display (HWD) technology provides an innovative solution to the challenges faced by car interior designers. This groundbreaking technology transforms conventional windshields into smart and transparent infotainment interfaces. It enables a seamless blend of advanced optical functionality and sleek design without the need for additional screens and bulky hardware. This not only achieves an intuitive and seamless in car infotainment experience for drivers and passengers, but also unleashes unprecedented design freedom for cockpit interior designers.

At the core of ZEISS' holography technology lies a holographic film which can be seamlessly laminated between the windshield layers to turn a plain windshield into a smart interface. This film is created with Holographic Optical Elements (HOEs) built within it. These HOEs enable precise control over the direction of light emitted from a laser-based Projector Generation Unit (PGU). It is through this integration of the thin holographic film and PGU that the HWD solution delivers a suite of standout features. Each feature addresses the pain points of traditional in-car display systems and unlocks new possibilities for automotive interior design.

Unprecedented design freedom: Minimal volume and flexible adaptability

For designers, the primary advantage of HWD lies in the unprecedented design freedom it delivers. Minimal system volume is a cornerstone enabler of this freedom. Traditional HUDs demand tightly constrained optical paths and substantial dashboard space to house bulky mirrors and lenses, imposing rigid limitations on interior layout. 

In contrast, HWD leverages HOEs to precisely control the direction of the light beams, eliminating the need for cumbersome mirrors, lenses and fixed PGU positioning. It requires only a windshield seamlessly laminated with holographic film and a compact PGU that can be flexible placed. 

The system volume is also decoupled from the increase of the Field of View (FOV) and eyeboxes. This revolutionary design slashes the package volume to less than 1.5 liter per PGU, empowering designers to position the PGU in locations that best complement the vehicle’s interior architecture. Furthermore, the technology is fully adaptable to diverse windshield geometries including curved surfaces. 

This is because unlike traditional HUDs that rely on windshield curvature for light reflection, the HOE-based approach is independent of glass shape. This frees designers from the physical constraints of conventional display systems, enabling them to craft bold, brand-defining glass forms without compromising display performance.

Maximum on-demand display capability: High transmittance and aesthetic preservation

Another defining feature is the maximum on-demand display capability. The HOEs are engineered to respond exclusively to specific light wavelengths and angles which eliminates interference from ambient environmental light, leading to an impressive transmittance of over 92%. Unlike PHUDs which often rely on a black background and are therefore limited in size, the HWD technology allows for flexible display sizing, as long as it complies with relevant regulations. The high transmittance feature also supports the on-demand functionality of the display. This means the display appears only when needed and reverts to a clear unobstructed windshield when inactive. This preserves the cabin's clean aesthetic while maintaining full functionality.

Personalisation and occupant-specific content: Meeting diversity and privacy needs

The HWD solution also opens new opportunities for personalisation and occupant-specific content delivery, a growing priority in the era of shared mobility and semi-autonomous driving. HOEs can be engineered to create display zones visible only within defined viewing areas or ‘eyeboxes’. 

By controlling the direction of diffracted light with great precision, ZEISS can ensure that certain information such as navigation data is visible solely to the driver, while other content like entertainment or contextual information can be directed only to passengers. 

Step outside the defined eyebox and the image disappears completely. This selective visibility enhances privacy and supports differentiated, personalised UX experiences. Additionally, dual eyebox configurations are available to enable seamless display sharing between occupants when needed.

Optimal brightness and clarity: Flawless performance in real world conditions

Of course, for any in-vehicle display to succeed, it must perform flawlessly under real-world lighting conditions. Optimal brightness and clarity further set the HWD apart. The HOEs enable precise control of light transmission which dramatically improves the efficiency of directing light to the designated eyeboxes. 

This means a compact PGU can achieve a luminance exceeding 10000 nits, ensuring the display remains highly visible even under direct sunlight. It is important to note that the display’s brightness is determined by the PGU, rather than the holographic optical elements. 

Additionally, HWD supports RGB display functionality which guarantees vibrant and accurate color reproduction. This enhances both the infotainment experience and the clarity of critical driver information. Another key clarity advantage of HWD is that it displays an “in plane” real image directly on the windscreen surface. This differs from the virtual image common to existing HUD solutions. This fundamental difference eliminates dynamic distortion issues. Since both eyes observe the same object regardless of their position within the eyebox, there is no dynamic distortion. This further enhances the display’s clarity and usability.

Future-proof performance: Analogue holography advantage

ZEISS adopted an analogue approach to generate holography which enables future-proof display performance. Unlike digital holography which has gaps between pixels, making a limiting factor for image quality, the analogue method employs laser technology to record a continuous layer of microstructure into the photopolymer. 

This ensures that the hologram does not become a bottleneck for display performance. As a result, analogue holography by ZEISS offers enough potential to address a resolution of 4k and even beyond, meaning the resolution can evolve as the PGU evolves.

Eco-friendly design: Energy efficiency and thermal advantages

Last but not least, the HWD system is eco-friendly. The holographic display demands only a fraction of the power consumed by an LCD-based system to achieve equivalent luminance. For instance, achieving 2500 nits requires only “3 x 6 Watts” for the holographic system, compared to approximately “3 x 30 Watts” for a classical LCD PHUD. This dramatic efficiency gain simplifies thermal management and reduces energy drain on the vehicle’s systems.

A new paradigm for in-vehicle display Design

ZEISS Microoptics’ HOE technology represents a new paradigm for in vehicle display design, allowing interior designers to work with fewer constraints than ever before. By controlling light with holographic precision, it enables privacy, personalisation and seamless visual integration that aligns with designers’ goals of sleek, harmonious interiors. And by supporting full aesthetic customisation, it turns technology into a powerful brand narrative.

As automotive UX continues to evolve, holographic transparent displays are poised to become a defining feature of next generation mobility. In this context, every beam of light, every hue and every animation contributes to a richer, more connected driving experience.