LIGHT CONTROLLING DEVICE

PURPOSE:To realize an agreeable visual environment by utilizing efficiently daylight. CONSTITUTION:Outdoor illuminance is measured by an outdoor illuminance measuring part 1, indoor illuminance is measured by an indoor illuminance measuring part 2, an incident angle of the sun is measured by a sun incident angle measuring part 3, and by these information, an optimal transmissivity of a glass substrate is calculated, based on an arithmetic program by an arithmetic part 4. To a control part 5 to which this arithmetic part 4 is connected, a DC voltage required for electronic grading is supplied by a DC power source part 6, and by a result of operation from the arithmetic part 4, transmissivity of glass substrate 7a-7t are varied independently and adjustment of an incident light quantity is controlled. Also, by reducing the transmissivity of the glass substrate of the lower part and heightening the transmissivity of the glass substrate of the upper part, a reflection of light caused by the strong sunlight on the upper face of a desk, etc., can be avoided, and also, from the upper part, daylight can be taken deeply into the inside of a house. Moreover, by sensing the light environment of the inside and the outside of a house and an incident angle of the sun which are varied momentarily, the daylight can be controlled automatically and more efficiently and it can be contributed to energy saving, as well.