HUD: From Fighter Jets to Smart Cars' "See-Through Dashboard"

HUD, which stands for Head-Up Display, offers a core benefit: it allows drivers to access critical driving information while keeping their eyes on the road and hands on the wheel. The concept was first proposed by the British Royal Air Force during World War II. In the 1960s, the U.S. military implemented it in F-4 fighter jets. Starting in the 1970s, commercial airliners gradually adopted HUD to assist pilots during takeoffs and landings in complex weather conditions, thereby reducing the risk of human operational error. By the early 2000s, automakers such as BMW and Mercedes-Benz began adapting HUD technology into their high-end vehicle models.

As vehicles become increasingly intelligent, HUD is transitioning from a high-end option to a mainstream standard feature. Today, automotive HUD has evolved into several forms: C-HUD (Combiner Head-Up Display) typically uses a separate piece of transparent resin glass as the projection medium; W-HUD (Windshield Head-Up Display) utilizes the windshield itself as the display surface; and the latest AR-HUD (Augmented Reality Head-Up Display) can seamlessly integrate navigation paths, pedestrian warnings, and other information with the real road environment. Industry forecasts suggest that by 2025, the installation rate of HUD in new vehicles globally will exceed 20%, with penetration in the Chinese market expected to be even higher.

However, the path to widespread HUD adoption has not been smooth. Issues such as image ghosting, blurry displays, and poor visibility in strong sunlight persistently challenge the industry. The root causes of these problems often lie hidden within the internal structure of the HUD unit. When the HUD's light source projector (PDU optical engine) operates, the emitted light can strike the internal walls of the device. Traditional interior wall materials cause unwanted reflections and refractions, generating stray light. This stray light overlaps with the primary display information, resulting in the driver perceiving ghosted or blurry images, which is particularly pronounced in bright environments. During nighttime driving, glare from substandard HUDs can increase visual fatigue for the driver, ironically introducing safety risks. Solving the issue of internal light interference has therefore become crucial to enhancing HUD quality.