US Patent 10168734 Foldable display device and display apparatus

A foldable display device includes a flexible display screen and a support back plate fitted to the flexible display screen. The support back plate includes a first support plate and a second support plate that is articulated with the first support plate by a double-shaft articulated mechanism. The double-shaft articulated mechanism includes a first rotation shaft pivotally coupled to the first support plate, a second rotation shaft pivotally coupled to the second support plate and a tension releasing mechanism provided between the first rotation shaft and the second rotation shaft.