436 



MECHANICAL AND ACOUSTICAL SENSES 



about 100 units. This, however, varies greatly with the companies involved. 

 Examples of hybrid thick-film circuits are those produced for the CSULB 

 shark transmitters by Keldron, Inc., Costa Mesa, Calif. (Figures 8 and 9), and 

 those described by Pincock and Luke (1975) for a smaller, pressure-sensing 

 transmitter. 



Thin-film hybridization— -This is a more sophisticated type of circuit 

 miniaturization derived primarily from monolithic technology. It allows 

 more compact packaging than thick-film hybridization but is somewhat 

 more costly in any quantity and much more costly in quantities of fewer 

 than about 1000. The smallest conductor lines and spaces are about 0.025 

 mm wide. Conductor and resistor patterns are produced by photo-etched 

 masks, using deposition techniques such as evaporation and sputtering. 

 Larger components are attached as in thick-film hybridization. 



tf ^JM ***** 



1 



Figure 9 Examples of thick-film hybrid circuits. Top: Potted and unpotted hybrids for 

 the Mark V basic transmitter (KD502, 16-pin) and the eight-channel multiplexer (KD533, 

 12-pin). Bottom: Closeup of details, including wire bonding of the CMOS integrated- 

 circuit chips to the substrate conductors. Hybrids produced by Keldron, Inc., 1281 E. 

 Logan Ave., Costa Mesa, Calif. 92626. 



