Light Modulating Device

A light modulating device is disclosed herein. In some embodiments, a light modulating device includes a first substrate, a second substrate, a light modulation layer, and a retardation film, wherein each of the first and second substrates has a first surface and a second surface, wherein the first and second surfaces are disposed opposite to each other, wherein the first surfaces of the first and second substrates face each other, wherein the light modulation layer is disposed between the first and second substrates, wherein the retardation film is formed on the second surface of the first substrate or the second substrate, and wherein the retardation film has an in-plane phase difference in a range of 100 nm to 300 nm for light having a wavelength of 550 nm. The light modulating device can be control omnidirectional light leakage in a black mode while having excellent optical properties and mechanical properties.