A series of experiments on the carbon-resin system thick film resistors of low temperature firing type has been conducted under various conditions of volume mixing ratio of carbon black particle (CB) and carbon fiber (CF) dispersed in binder resin in order to obtain resistors with any desired resistivity as well as with excellent electrical characteristics. From the experimental results optimum conditions in volume ratio of CB against CF, (CB/CF), and volume fraction of CB+CF against total resistor materials including binder resin, , have been found to minimize temperature coefficient (TCR), current noise index (NI) and variation of resistance in heat cycle (VHC).

Conventional metal-glazed thick-film resistors are applied to Hybrid Integrated Circuits, chip resistors and others. These resistors are usually fired at a high temperature of around 850C on ceramic substrates. Recently, however, attempts have been made to fire some metal-glazed thick-film resistors at lower temperatures on glass substrates for application as the control resistors for the discharge current of dc Plasma Display Panels (PDPs). We have attempted to realize such low-firing-temperature thick-film resistors using Pb2Ru2O7-x as conductive particles, two kinds of lead-borosilicate glasses as binders, and three kinds of metallic oxide as additives, which are fired at 580C on a soda lime glass substrate. The electrical properties of the specimens, 16 kinds in all, fabricated from various combinations of binder glasses, additives and electrode materials have been measured. Effective dimensions of the specimen resistor are 0.25 0.25 mm2 or less in surface area, since extremely small size is required by PDPs. The effect of the combination of additive and binder glass on the conductive particles of Pb2Ru2O7-x has been examined in detail, together with the affinity for electrical conjunction between resistor and electrode.