A bedsore reduction system for beds includes a generally rectangular base plate, a mattress support plate and a diagonal connecting plate extending between said base plate and said mattress support plate and pivotably connecting the opposite side edges of the base plate and the mattress support plate. The memory cell includes a poly-silicon island, a first dielectric layer, a trapping layer, a second dielectric layer and a control gate. A gate level dielectric layer including a first dielectric material is deposited and subsequently planarized employing the raised source and drain regions as stopping structures. 3 \u03bcm and a delay time of an element response accompanying a transit of carriers generated in the light absorbing layer by light absorption takes on a local minimum under a condition that a layer thickness WA of the light absorbing layer is constant.