Human Eye Contrast Sensitivity to Vehicle Displays under Strong Ambient Light

Vehicle displays are becoming more integrated into our daily lives. Achieving a premium driving experience demands the display panel to have high-resolution density and sufficient brightness, particularly when exposed to intense ambient light, as direct sunlight can obscure the displayed images. Combining Barten’s model and diffraction theory, the performance of both infotainment displays and head-up displays (HUDs) is evaluated. For infotainment displays, over 800 nit brightness is essential for the driver to discern 55 pixel-per-degree (PPD) patterns under direct sunlight. For HUDs, a delicate balance between resolution density, brightness, transparency, and image quality must be exercised. By slightly reducing the resolution density to 50 PPD, the transparent micro-LED panel can concurrently achieve a reduced background image blur, low required display brightness (~4000 nits), and high background transmittance (~90%).