Ambient lighting strategy of visual display terminals in micro-space luminous environment under low-light conditions

• Improve the visual comfort under low-light visual display terminal (VDT) conditions. • Adding ambient lighting behind the VDT screen to form a more comfortable and healthy lighting pattern. • Establishing the functional relationship between preferred luminance and size of ambient lighting by ergonomic experiments. • Facilitating design and optimization of dynamic low-light VDT environments. Visual display terminals (VDTs) are integral to contemporary life, creating a unique micro-space luminous environment with self-luminous screens and lighting backgrounds which requires optimal lighting conditions. Especially in low-light conditions, improper luminance contrast between the VDT screen and its background may affect visual comfort and clarity. To alleviate this problem, this work proposes adding ambient lighting around the VDT screen background to form a more comfortable and healthy lighting pattern, and improve the comfort zone. Through ergonomic experiments, we find the new visual comfort threshold and zone by adjusting ambient lighting in terms of luminance and size. Results show that the VDT screen optimal luminance range extended from 32-66 cd/m² to about 68-110 cd/m², and the visual central zone luminance ratio improved from 1:3 to 1:6. The luminance of ambient lighting preferred by participants decreases with the increase of size, and remains stable when the luminance ratio with VDT screen is close to 1:2, with an ideal size of 30%-40% of the VDT screen's width and length. These findings provide a strategy to enhance visual comfort and optical health, offering valuable insights for designing a comfortable and healthy low-light conditions, such as nighttime cockpit or indoor VDT tasks.