A study on voltage efficiency of bored electrodes for ADP electro-optical elements has been made by means of the electrolytic cell method. At first, center voltage efficiency is measured and the effects of the width of the electrode, the diameter of the hole, the gap of the electrodes and so on are investigated. Next the relation between these values and the mean voltage efficiency are studied. The electrodes which are studied are 4 kinds of single hole electrodes (ring, square, hexagonal and slit) and 3 kinds of net electrodes (lattice net, hexagonal net and fluted net). The following result is found for all kinds of electrodes. The center voltage efficiency ec is expressed, if the variables are within some limitted range, logec=-αd/t+Alogb/d+B0+Clogn
where α, A, B0 and C are constants which depend only on the type of electrodes. The mean voltage efficiency e is expressed e=mec-m+1 where m is the constant which also depends only on the type of electrodes.
