Light control plate unit, area light source device, and transmission-type image display device

Provided are: a light control plate unit which can uniformize light emitted from a point light source; an area light source device; and a transmission-type image display device. The light control plate unit (21) is provided with first and second light control plates (30 1 , 30 2 ) each of which has, formed on one surface thereof, multiple convex parts (33 i (i = 1, 2)) that extend in one direction (an extending direction) and are arranged in rows in the direction approximately perpendicular to the extending direction. The two light control plates (30 1 , 30 2 ) are arranged in the thicknesswise direction of the unit, and the direction in which the convex parts (33 i ) on one of the light control plates extend is approximately perpendicular to the direction in which the convex parts (33 i ) on the other of the light control plates extend, and the shapes of the cross sections of the convex parts (33 i ) independently fulfill the formula 0.95z 0 (x) ≤ z(x) ≤ 1.05z 0 (x) when x fulfills the formula -0.475w a ≤ x ≤ 0.475 w a , wherein w a represents the width of each of the convex parts in an x-z coordinate system in which the axis line that passes through both ends of the corresponding convex part is an x-axis in a perpendicular cross section of each of the convex parts in each of the light control plates which is approximately perpendicular to the extending direction. In the above-mentioned formula, z 0 (x) fulfils the formula (1). (In formula (1), each of C 2k 's respectively corresponding to k = 1-8 represents a predetermined constant value).