Traditionally used by shops, restaurants, public bathhouses, etc. for sunshade, blinder and to indicate they are open. Interior use is for preventing kitchen smoke and smells to the other room. Blinder for the entrance of Onsen (hot spring). The pattern is so unique some has character like "ゆ" or "♨︎" use for bathhouse or Onsen, and are decorative. if you are interested in it, here some you can buy from Japan Rakuten Global.
Cool decorative NOREN
To help you to buy stuff direct from Japan through Japan's largest and well known online shop Rakuten and amazon.jp