A chair, preferably a beach chair, equipped with a simple, foldable, and lightweight sun-shading device that is integrally connected with or built into the chair and, when not in use, is hidden inside the body of the chair. The segment determination unit 36 determines, with respect to a homogeneous segment that is similar to segments constituting a first text which is set as an analysis target and that is included in another first text, whether the content thereof is included in a second text. The integral refractive outer and inner surfaces each define a predetermined geometry adapted to direct and focus light emitting from the LED to a predetermined path. When the current or voltage across the electrodes increases beyond a threshold, the excess current or voltage will cause a bubble to be created within the fluid to reduce or inhibit the flow of electricity between the electrodes.