RONEN transflective TFT LCD display
Under bright illumination (e.g. when exposed to daylight) the display acts mainly as a reflective display with the contrast being constant with illuminance. Only in dim and dark ambient situations is an auxiliary transmissive backlight needed.
When an illuminance sensor is added for control of the backlight, such a transflective LCD can be read over a wide range of illuminance levels. This technique is often found in automotive instrumentation. In portable electronic devices the transflective mode of operation helps to save battery charge, since in bright environments no backlighting is required.
The essential component for a transflective LCD is the transflector, a polymer sheet that is reflecting and transmitting at the same time.
Some displays that transmit light and have minor reflectivity are best readable in the dark and fairly readable in bright sunlight, but only under a particular angle; they are least readable in bright daylight without direct sunlight.