To lower the power consumption of a display device while facilitating the reflection and scattering of the light by a film, restricting the scattering of the light emission to a back surface substrate side, and while restricting the dielectric constant of the film by using the ceramic filler having a different reflectance from a low-melting point glass in an insulating film of the back surface side substrate.

This insulating film forming material as a raw material for forming an insulating film in a panel surface formed with electrodes of a display device by patterning is obtained by adding the paste oil to a base composed of 60-90 wt.% of a low-melting point glass and 10-40 wt.% of two or more kinds of the filler to be selected among rutile, anatase, corundum, quartz, cristobalite or amorphous silica, and adjusting them. In this display device, the insulating film made of the insulating film forming material has 40% or more of visible light reflectance and 18 or less of dielectric constant, or has 30% or more of visible light reflectance and 15 or less of dielectric constant.