Combiner Head-Up Display (C-HUD)

Definition and Technical Principles

C-HUD, short for Combiner Head-Up Display, represents the first generation of automotive head-up display systems. Unlike Windscreen HUD (W-HUD), which projects directly onto the vehicle's windscreen, C-HUD utilises a standalone semi-transparent resin combiner mounted on the dashboard, where the Picture Generation Unit (PGU) projects driving data—such as vehicle speed and turn-by-turn navigation—onto the screen to reflect a virtual image into the driver's line of sight. Its defining characteristic is having a display unit completely independent of the vehicle's structural components.

Hardware Specifications and Performance

The optical system of C-HUD delivers fairly baseline technical specifications. The virtual image distance (VID) typically ranges between 1.2 and 2.5 metres, with a field of view (FOV) of 4°×1.5° to 6°×3°, an eyebox measuring at least 130mm×50mm, and a peak brightness reaching 5,000 to 10,000 cd/m². In terms of visual quality, virtual image distortion across the entire eyebox is kept within 5%, while the central eyebox contrast ratio is rated at no less than 1,000:1.

Market Positioning and Current Status

C-HUD is primarily tailored for entry-level models and the aftermarket segment. Its main strengths lie in low R&D costs, minimal development complexity, and ease of retrofitting, with aftermarket units typically retailing from a few hundred up to a thousand RM. By employing a standalone resin combiner, C-HUD bypasses the need for bespoke optical windscreen designs, significantly reducing OEM integration complexity. However, this setup comes with clear compromises, notably rudimentary display readouts (usually limited to vehicle speed and basic multimedia prompts) and constrained image clarity.

Safety Considerations

C-HUD also carries inherent crash safety risks. Because the rigid resin combiner is mounted exposed atop the dashboard, it risks detaching or shattering during an impact, potentially inflicting secondary injuries on the driver. This structural drawback has been a primary catalyst behind the industry's shift towards W-HUD and AR-HUD setups. As a result, C-HUD is virtually phased out in today's mainstream new car market, remaining relevant only in older vehicle models and select aftermarket applications.