This SAE Recommended Practice provides test protocols with performance requirements for vehicular flat panel display systems efficiency. The standard help determine vehicle the display system light efficiency vector KDS = (K50, Knight, Kdaytime, Khigh-ambient) with the highest optical performance (such as luminance, contrast) and lowest power density (defined as total power divided by active area of the display), based on typical automotive usage such as ambient lighting.
In this standard, we are measuring Lamb to determine Eamb value such as 1.592 cd/m2 measured off a 0.99 standard diffuser equivalent to 5k lux illumination environment, same as in SAE J1757-1.