| 摘要 |
<p>1391375 Resistors HEWLETT-PACKARD CO 25 April 1973 [5 May 1972] 19695/73 Heading H5H [Also in Division H1] A process for fabricating a thick film resistor upon an element comprises depositing a crystallizable dielectric thermally insulating layer on the element, firing the dielectric layer, depositing a cermet resistive material upon the dielectric layer and firing the resistive material in an oxidizing or neutral atmosphere. As shown, a glass and alumium oxide dielectric 4 of low thermal conductivity is screen printed on to a ceramic, e.g. alumina substrate 5, having a heat sink 6. The dielectric is allowed to dry and then fired in air at a temperature between 850‹ and 1100‹C. for a period greater than 10 minutes typically at 940‹ C. for 5¢ hours. Conductors 2, 3 of gold, palladium, silver, platinium gold or palladium gold alloy are screen plated on to dielectric 4 or substrate 5, and then fired in air in the above temperature range. A thick film resistor 1 containing bismuth ruthenium oxide is then screen plated on to the dielectric 4 in one or more layers of between 0À0005 and 0À01 inch thickness with firing and lapping for each layer or after the final layer, the lapping being used to acquire the required coefficient of resistance or resistor value. The resistor is then annealed and the conductors covered in an abrasion resistant layer 7. The resistor may be used as a thermal printer.</p> |
