A panel bottom member structure includes a panel bottom member including a light absorbing member, a top bonding layer disposed on the light absorbing member, an acoustic vibration element disposed beneath the light absorbing member and generating a vibration in response to an acoustic signal, and a buffer member disposed beneath the light absorbing member and non-overlapping the acoustic vibration element, and an element circuit board connected to the acoustic vibration element and provided with an acoustic element driving chip for generating the acoustic signal.