A reconstructed image with less noise is reconstructed from a lens array image. The upper plate has an embossment projecting in and a pressing portion extending from the upper edge of the right side plate is placed into contact with the upper surface of the embossment to prevent an upward movement of the upper plate. The male part engages with the female slot in such a way as to allow limited controlled relative movement between adjacent cover elements on assembly in both the horizontal and vertical planes.