BLIND DEVICE

PURPOSE:To automatically adjust a slat angle in response to the ON/OFF operations of an image device a building and the degree of visual comfort for characters and figures indicated over a display scope, and enable daylighting according to an usage condition. CONSTITUTION:The power supply 14 of an image device sends its ON/OFF information to a slat angle control section 15. When the power supply 14 is turned off, the slat angle control section 15 drives a variable slat angle motor in such a way that a slat angle is controlled up to a critical profile angle (a critical angle interrupting the incidence of direct sun shine), so that daylight is admitted in the inside of a building to the maximum extent. When the power supply is turned on, the slat angle control section 15 drives the variable slat angle motor to control a slat angle in such a way that visibility VL operated by a VL operating section 10 will be in a range of 7 to 10 based on illuminance information from a circumference light receiving section 9, scope brightness information 12 from a display scope 8, and liquid crystal element permeability information 13 from the display scope 8.