The invention provides a backlight capable of inhibiting right side brightness nonuniformity, oblique brightness nonuniformity and stud pin visibility. The backlight comprises linear light source of emitting light and a stacked body with an incident face for incidence of light emitted by the linear light source and an emergent face for emitting light incident from the incident face. The stacked body comprises a forming diffusion plate and a prismatic lens, and the forming diffusion plate and the prismatic lens are stacked in sequence from the incident face to the emergent face. The forming diffusion plate is provided with an incident face for incidence of light emitted by the linear light source and an emergent face for emitting light incident from the incident face, a plurality of triangular-prism-shaped projections with curvature R at top are repeatedly arranged on the emergent face, the bottom angle of the projections is larger than or equal to 38 DEG and less than 42 DEG, and the ratio R/Cp of the curvature R formed at the top of the projections to the distance Cp of the projections is larger than 0.0014 and less than 0.43.