Abstract: An illumination control system includes a signal detection unit for detecting a signal changed depending on an eye state of a person, an opening/closing determination unit for determining an opening/closing state of an eye of the person based on the detected signal, and a sight line detection unit for detecting a person's sight line direction with respect to an illumination device based on the detected signal. The illumination control system further includes a control unit for controlling the illumination device to reduce an illuminance when the opening/closing determination unit determines that the eye of the person is in a closed eye state, and to change an illuminance and a light color based on the sight line direction detected by the sight line detection unit when the opening/closing determination unit determines that the eye of the person is in an open eye state.

Abstract: An illumination control system includes a signal detection unit for detecting a signal changed depending on an eye state of a person, an opening/closing determination unit for determining an opening/closing state of an eye of the person based on the detected signal, and a sight line detection unit for detecting a person's sight line direction with respect to an illumination device based on the detected signal. The illumination control system further includes a control unit for controlling the illumination device to reduce an illuminance when the opening/closing determination unit determines that the eye of the person is in a closed eye state, and to change an illuminance and a light color based on the sight line direction detected by the sight line detection unit when the opening/closing determination unit determines that the eye of the person is in an open eye state.

Abstract: A hydrophobic aerogel is fabricated by reacting a polymer having a skeleton structure of (SiO.sub.2).sub.n with a hydrophobic agent having hydrophobic groups as well as functional groups reactive to silanol groups to obtain a denatured polymer, forming a gel consisting of two phase of a dispersing medium and the denatured polymer which was performed a hydrophobic treatment, and then, supercritically drying the gel at temperature and pressure above a critical point of the dispersing medium. The hydrophobic aerogel has improved characteristics free from deterioration in light transmissivity as well as lowered thermal resistance and also free from a dimensional variation such as shrinkage which would otherwise occur by contact with moisture, so that it can maintain the excellent characteristics for long time periods. Particularly, the aerogel is useful as a material having excellent light transmissivity and thermal resistance.

Abstract: A hydrophobic aerogel having excellent transparency is formed by the following process of the present invention. That is, a first gel having a SiO.sub.2 skeleton structure is prepared by hydrolysis and condensation of an alkoxysilane compound in the presence of a solvent. The solvent contained in the first gel is replaced at least partially with a medium to form a second gel. The second gel is reacted with a hydrophobic agent having hydrophobic groups as well as functional groups reactive with silanol groups under a supercritical condition of the medium to form a hydrophobic gel. The medium contained in the hydrophobic aerogel is removed by a supercritical drying method, so that the hydrophobic aerogel having improved transparency and an extremely fine porous structure is obtained.