| 摘要 |
PURPOSE:To readily adjust the transmission of light by disposing driving rolls for winding a belt at both the ends of the belt composed of plural films or sheets having different light transmissions, respectively, and connected to each other in an order of the light transmissions and supporting the belt with plural auxiliary rolls. CONSTITUTION:A belt 3 is wound up or back to adjust an illumination degree in a green house, the belt 3 being prepared by disposing films or nets in an order of the light-screening degrees thereof and subsequently heat-bonding or adhering with an adhesive, etc., to each other so as to enable to be spread or wound with driving rolls 4a and 4b and auxiliary rolls 5. The light-screening degrees are adjusted by changing the transparencies of the films or changing the opening degrees of the nets. |
