Asa Huang discusses the trend for AR displays and their role in the automotive sector’s future
What is an AR HUD?
As a reminder of driving safety, the augmented reality (AR) HUD display is a projector that displays ADAS and driving information in front of the driver’s view. The main reason for the lack of previous HUD designs was that the TFT-LED display was not bright enough, the image block was not large enough, and had a poor virtual effect in actual use.
FIC’s sunlight readable (SR) AR HUD uses a laser beam scanning (LBS) projection technique, which can solve the problems encountered in the previous HUD design. With high contrast and small divergence angle, AR HUD provides many advantages.
AR HUD advantages
AR image display quality is in multi scenes and is sunlight readable. Secondly, the best contrast of AR HUD (80000:1) can clearly mark and identify image information, and the driver can clearly distinguish the path and virtual graphics while driving on the road.
For the presentation of virtual imaging distance (VID) and image size, the overall optical design adjustment angle is required and must be well designed, including the addition of sensing elements. LBS projection technique is not quite like usual projectors. It doesn’t require any focus lens for image adjustment; therefore, its volume size is smaller than DLP or TFT projection. All holographic images are projected by laser beams composing with RGB colour, hence the laser beam colour adjustment becomes one of the most significant techniques during design. There is no need to adjust the focal length – which reduces the customer cost on designing windscreens.
AR HUD improvements
The difficulty of AR HUD assembly is to integrate all kinds of information, software and hardware together and control the IP structure volume size.
To improve the configuration rate and experience, and further realise AR HUD, the use of laser AR HUD can improve quite a lot of effects, but more attention should be paid to the design capability itself, including projection technique, optical design, system integration, programming and other factors to limit the display effect, heat dissipation function, optical path design and other necessary considerations. Those may lead to the size of IP structure being very large. In addition, in ghosting, image clarity and AR effect, it is necessary to cooperate with the front windscreen, driver monitoring and other components for targeted optimisation.
The effect of projection display is determined by the brightness of projected light and ambient light. In direct sunlight, the ambient light in front of the car is often very strong. To improve the display effect, it is necessary to improve the brightness of AR HUD, but high brightness brings heat. Therefore, if AR HUD can operate stably in the high temperature environment of cockpit, it must have efficient heat dissipation structure and system.
It is an important feature of FIC’s AR HUD to display virtual information directly on the real road. It is necessary to accurately locate the projection channel of the information displayed by HUD, so that the human eye, HUD display surface and the real road are in one line of sight, so as to achieve AR experience, which requires strong computing power.Instead of using TFT or DLP techniques, FIC believes that LBS AR HUD will be a market trend for driving in the near future before autonomous driving becomes mature.
Asa Huang is with FIC