A PDP with superior light-emitting characteristics and color reproduction is achieved by setting the chromaticity coordinate y of light to 0. The substitute certificate is used as a replacement for the certificate chain. The drill blocks can move along the length of the base plate so that the drill blocks can be configured to conform to a desired hole pattern. A planar focusing cathode includes a selected dielectric material, such as a ceramic material, to provide an electron beam emission surface. According to the invention, a microcontroller controls the electronic switch element. The value of X defines an atomic percent of germanium satisfying 0.