A technique for distributed processing a partitioned model is provided based on tight functional coupling of multiple submodels of the model. The backlight sheet has one or more electroluminescent panels attached to it. The ONU transmitter transmits the encoded end user data to an optical line terminal receiver, which demodulates the data using a PAM demodulator and sends it to a service provider. The respective pixel-driving IC chips include a plurality of pixel circuits, each of which drives each organic EL element corresponding to the pixel circuit.