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How does a transflective LCD work in bright and dim surroundings?

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Diagram comparing three liquid crystal phases: nematic with parallel rods aligned vertically, smectic A with rods arranged in horizontal layers, and smectic C with rods in tilted layers. — liquid crystal display Liquid crystal arrangements
In nematic arrangements the crystals are randomly positioned with all their long axes pointing in essentially the same direction, given by a vector known as the director. In smectic arrangements the crystals are further constrained to parallel planes; in smectic A the director is perpendicular to these planes, while in smectic C the director is at some other angle to the planes.

Transflective liquid crystal displays (LCDs) are designed to function effectively in varying lighting conditions by combining features of both reflective and transmissive display technologies.1

Mechanism in Different Environments

Bright Surroundings: These displays utilize a partially reflective and partially transmissive mirror positioned between the liquid crystal layer and the backlight. In high ambient light, the backlight can be turned off, allowing the display to function as a reflective device by bouncing external light back toward the viewer. This process significantly reduces battery consumption.1
Dim Surroundings: When ambient light is insufficient, the internal backlight is activated. This light passes through the partially transmissive mirror, providing the necessary illumination to ensure the display remains visible and bright.1

While this dual-mode capability offers significant versatility, transflective displays are inherently a compromise. They generally cannot achieve the peak reflectivity of a dedicated reflective display or the maximum brightness of a purely transmissive device.1