Light control device and light control sheet

A light control device, comprising:

• a light control sheet comprising a first transparent electrode layer, a second transparent electrode layer, and a light control layer formed between the first transparent electrode layer and the second transparent electrode layer;
• and
• a control unit comprising circuitry configured to apply a first voltage between the first transparent electrode layer and the second transparent electrode layer to bring the light control sheet into a first state in which infrared light is reflected and visible light is transmitted, apply a second voltage greater than the first voltage between the first transparent electrode layer and the second transparent electrode layer to bring the light control sheet into a second state in which infrared light and visible light are scattered, and apply a third voltage greater than the second voltage between the first transparent electrode layer and the second transparent electrode layer to bring the light control sheet into a third state in which infrared light and visible light are transmitted,
• wherein the light control layer in the light control sheet includes a transparent polymer layer including voids and a liquid crystal composition retained in the voids and comprising chiral nematic liquid crystals having positive dielectric anisotropy, and
• the liquid crystal composition in the light control sheet satisfies 0.8≤P×(ne+2no)/3≤2.2, where P is a helical pitch in μm, no is an ordinary light refractive index, and ne is an extraordinary light refractive index.