Flexible layer support structure and retractable device

A flexible layer support structure, comprising at least two thin sheets overlapped with each other and at least two folding springs sandwiched between the thin sheets in parallel;

• the folding springs are arranged parallel to each other along a first direction of the thin sheets, and each of the folding springs is a long waveform compression spring formed by even number of curved elastic pieces in series connection extending along a second direction of the thin sheets;
• the folding springs have an elastic trend of prop opening the thin sheets on two sides, and all of the curved elastic pieces are overlapped with the thin sheets to form a layer structure after being compressed;
• outer edges of the curved elastic pieces at two outer ends of the folding springs are smoothly lapped with adjacent thin sheets, and a hollow thin-walled layer structure with bending stiffness is formed between the folding springs and the thin sheets;
• when the thin sheets are subjected to sufficient overlapping pressure in a deformation direction of the folding springs, all the thin sheets and the folding springs are overlapped into the layer structure that is capable to be bent or rolled up;
• and the folding springs quickly and elastically prop open the thin sheets to restore an original state after the overlapping pressure is removed;
• wherein the thin sheets comprise a first thin sheet and a second thin sheet;
• all of the folding springs are distributed within a projection area where the first thin sheet and the second thin sheet overlapped with each other;
• connection positions between the curved elastic pieces and the first thin sheet and the second thin sheet are fixed joint parts, connection positions between the curved elastic pieces within the projection area of the first thin sheet and the second thin sheet are free joint parts, and the free joint parts translate along the first direction of the thin sheets during folding and unfolding process of the folding springs, the free joint parts of adjacent folding springs are arranged in face-to-face direction or opposite direction, and a gap is set between the free joint parts arranged in the face-to-face direction for the free joint parts to translate;
• surfaces of the curved elastic pieces of the folding springs, the first thin sheet, and the second thin sheet are provided with concave-convex structures that engage with each other under a folded and overlapped state of the flexible layer support structure.