Originally designed for military use, the head-up display (HUD) places important information (such as the current speed, and turn-by-turn navigation directions) right in the driver's line of sight.
Originally designed for military use, the head-up display (HUD) places important information (such as the current speed, and turn-by-turn navigation directions) right in the driver's line of sight.
( Source: TI)

Head-Up Display What you need to know about Head-Up Displays (HUDs)

Author / Editor: Jason Unrau / Erika Granath

A paperback-sized transparent projection on the windshield is a feature found in premium trim levels and luxury cars. Head-Up Display technology is centered around keeping the driver's focus on the road.

Fighter jet pilots have used them for decades, but they're relatively immature in the automotive and other sectors. Head-Up Displays, or HUDs for short, are a simplistic way to display pertinent information in a way that is less distracting and intrusive. How they work and the options available can be muddled, and a HUD's benefits aren't often understood well.

Let's explore the principles behind Head-Up Displays, the applications, and what the future holds for this technology.

What's a Head-Up Display?

Any display that can be visually projected into a user's view can be considered a head-up display. Put simply, a HUD is a projection unit that emits a brightly lit image, video or display onto a transparent surface.

The purpose of HUDs in cars is to eliminate users' need to take their gaze away from where it should be. While it only takes a fraction of a second to glance down at gauges and back up, a moment is required to re-focus your sight. And one moment of distraction is as familiar all it can take to lose control over a vehicle.

In aircraft and automobiles alike, HUDs put details directly into the pilot or driver's field of view where their vision remains forward where dangers lie.

A brief history of HUDs

Like many great technologies, head-up displays originated as military-use systems. Rudimentary yet revolutionary HUDs were developed for uses like radar displays in the cockpit of a fighter jet to eliminate the transition between a backlit radar screen and the dark sky at night. Fighter jets have developed incredibly detailed HUDs for various uses, whether navigation or weapons based.

In the 1970s, HUDs were introduced for commercial aviation, but the technology wasn't widely adopted until very recently. They're now standard equipment on the Boeing 787 and the Airbus A380 also features this technology.

In mobility, HUD technology adoption has been slower. Though first introduced in 1988, only a few select luxury nameplates had started to include the feature in their models at the turn of the last century.

Recently the adoption of HUD in cars has grown almost exponentially, though. While General Motors was the first carmaker to install HUDs, Nissan, BMW, Citroen, Mercedes-Benz, Toyota, VW, and practically all other carmakers have incorporated HUDs in at least one model in their lineup.

What information can an HUD show?

Related to mobility, a litany of details can be projected by Head-Up Displays. Here are a few examples:

  • Current rate of speed is perhaps the most sought-after information shown on an HUD. All others tend to be supplemental.
  • Turn-by-turn navigation directions are a popular feature that drivers appreciate in an HUD.
  • Posted road signs, picked up by Traffic Sign Recognition systems, project the speed limit on your current stretch of road as well as any construction or warning signs.

You can add a HUD to your current car

Aftermarket Head-Up Display systems have reached the market and can be installed in your vehicle. However, the available systems are basic and lack many of the features factory-installed systems include such as ADAS displays.

There's a wide range of add-on HUDs. Systems range from smartphone-based reflective HUD displays to small screens that are plugged into your car's OBD2 diagnostic port. The three most common types are:

  • Hudway Glass uses your smartphone's display to project travel details onto a transparent glass screen mounted on your dash. This system requires an app that produces a mirror image of your phone screen. With Hudway, impressive detail can be achieved without any cords or advanced installation. On the other hand, with this system, you're limited to the information available on your phone.
  • SHEROX HUD display is a wired system that projects basic travel info onto your windshield. The compact 3.1-centimeter (3.5-inch) device can show your speed, coolant temperature, voltage, and a couple of warnings indicators.
  • ACECAR Universal HUD system does much the same as the previous HUD but with more options. In addition to providing information on driving speed and basic warnings indicators, it includes a simple RPM gauge and a driving timer.