Planar light source device, display device, terminal device, and method for driving planar light source device

摘要

A display device having an optical waveguide and a light source are provided, and also having a louver, a transparent/scattering state switching element, and a transmissive liquid crystal display panel provided in the order indicated on the side of the light-emitting surface of the optical waveguide. The transparent/scattering state switching element switches between a state for scattering the incident light and a state for transmitting the light without scattering. The light source drive circuit causes the transparent/scattering state switching element to transfer from the transparent state to the scattering state, and when the viewing angle range of the display is switched from narrow to wide, the intensity of the light source is gradually increased in conjunction with the transition state of the transparent/scattering state switching element. By this configuration, abnormal flashing during switching of the radiation angle can be prevented in a planar light source device that is capable of switching the radiation angle range.