The spacers bond the substrate to {TAIL ~ the transparent counter substrate} and maintain {HEAD ~ a prescribed cell gap} 
The spacers bond the substrate to { TAIL ~ the transparent counter substrate } and maintain { HEAD ~ a prescribed cell gap }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD