A light source device and display device capable of suppressing occurrence of unevenness in luminance therefrom by using a light guide with concave or convex structural portions in combination with a reflection layer disposed adjacent the light guide and including a plurality of spacers for strategically positioning the layer's reflecting surface from the light guide. Light within the light guide is both reflected from the guide (e.g., to an adjacent display panel) or emitted onto the reflecting surface and passed back through the guide for eventual emission (e.g., to the same display panel). A reflection sheet including a base sheet, reflection layer and structural portions is also provided.