An AR HUD system has many design parameters. While all system parameters are important, there are two system parameters that are most responsible for determining PGU requirements in a HUD system: FOV and eyebox size. The following sections describe the high level tradeoffs associated with HUD FOV and eyebox size.

FOV in a HUD system is the solid angle of the displayed image, measured from the center of the eyebox. Typical FOV ranges from 4° × 2° in a small, conventional HUD up to greater than 12° × 6° in a large AR HUD. A larger FOV increases the size of the image seen by the driver. To achieve a larger eyebox, the HUD design must use a PGU with a higher luminous output to maintain the same brightness image. The DLP3030-Q1, combined with an LED based optical system, can output up to 90 lumens at room temperature and over 60 lumens across the entire automotive qualified operating temperature range (–40°C to 105°C).

Eyebox is the area at the viewing plane where the displayed image is visible to the driver. Typical eyebox sizes range from 100 mm × 60 mm to much larger 140 mm × 140 mm. A larger eyebox allows the driver to move their head further from center and use different seat positions while maintaining visibility of the displayed image. A large vertical eyebox also allows drivers of different heights to accurately see the image without adjusting any internal HUD components like mirrors. Because a larger eyebox spreads the image light out more than a smaller eyebox, larger eyeboxes require a higher lumen PGU to achieve the same brightness image.

Figure 2-3 provides an estimated PGU brightness requirement to achieve 15,000 nits (cd/m²) for given eyebox and FOV specifications. For an eyebox size of 140 mm × 60 mm with a 10° × 5° FOV, approximately 55 lumens are required from the PGU.

Figure 2-3 PGU Lumens vs Eyebox Dimensions and Field of View