Light guide plate assembly, lateral-entrance backlight source module and display device

The invention provides a light guide plate assembly, a lateral-entrance backlight source module and a display device, relating to the technical field of display. Local dynamic light modulation can be realized in different areas of a backlight source via the light guide plate assembly, and the image display contrast is improved. The light guide plate assembly comprises a first substrate, a second substrate opposite to the first substrate, and light modulation units between the first and second substrates; each light modulation unit comprises a first electrode, a second electrode and an electrophoretic capsule layer, the first and second electrodes are arranged close to the first and second substrates respectively, an electric field is formed between the first and second electrodes, the electrophoretic capsule layer is composed of electrophoretic capsules, each electrophoretic capsule comprises white electrophoretic particles and black electrophoretic particles, the white and black electrophoretic particles are dispersed in a transparent disperse medium, and the charge carried by the white electrophoretic particles is opposite to that carried by the black electrophoretic particles; and the first substrate is placed in the light extraction side of the light guide plate assembly, and the first substrate and the first electrode are transparent.