Electrolytic apparatus having a stable reference electrode and method of operating such apparatus
First Claim
1. An apparatus for use with a source of electric current and an electrochromic cell having a working electrode, a first reference electrode for sensing the potential of the cell and drive means for depositing material on and removing material from the working electrode, said apparatus comprisingfirst switching means for connecting the first reference electrode to a first source of electric current to cause deposition of material on the first reference electrode,second switching means for connecting the first reference electrode to the drive means to provide an indication of the cell potential,a second reference electrode in said cell, said second electrode adapted to serve as an alternate for the first reference electrode in sensing the potential of the cell, said second electrode adapted to serve as a control during the potentiostatic erasure of the first reference electrode,third switching means for connecting said second reference electrode to a first source of electric current to cause deposition of material on the second reference electrode,fourth switching means for connecting said second reference electrode to the drive means to provide an indication of the cell potential, andreference means connected to said first and second switching means for controlling the deposition of material on the first reference electrode, said reference control means connected to said third and fourth switching means for controlling the deposition of material on said second reference electrode wherein said reference means causes alternate operation between said second and said fourth switching means so that only one of the reference electrodes is always connected to the drive means.
1 Assignment
0 Petitions
Accused Products
Abstract
Electrolytic apparatus employing a reference electrode, e.g. an electrochromic display of the type employing potentiostatic control of write or erase operations, has at least one reference electrode on which a predetermined coating thickness of electrochromic or other electrodepositable material is maintained or replenished by intermittent connection of the electrode to a source of write current. Such a coated reference electrode has a stable potential with respect to the solution which is necessary for potentiostatic control. Two such reference electrodes may be used alternately such that one is being erased and rewritten while the other is connected as a reference.
17 Citations
5 Claims
-
1. An apparatus for use with a source of electric current and an electrochromic cell having a working electrode, a first reference electrode for sensing the potential of the cell and drive means for depositing material on and removing material from the working electrode, said apparatus comprising
first switching means for connecting the first reference electrode to a first source of electric current to cause deposition of material on the first reference electrode, second switching means for connecting the first reference electrode to the drive means to provide an indication of the cell potential, a second reference electrode in said cell, said second electrode adapted to serve as an alternate for the first reference electrode in sensing the potential of the cell, said second electrode adapted to serve as a control during the potentiostatic erasure of the first reference electrode, third switching means for connecting said second reference electrode to a first source of electric current to cause deposition of material on the second reference electrode, fourth switching means for connecting said second reference electrode to the drive means to provide an indication of the cell potential, and reference means connected to said first and second switching means for controlling the deposition of material on the first reference electrode, said reference control means connected to said third and fourth switching means for controlling the deposition of material on said second reference electrode wherein said reference means causes alternate operation between said second and said fourth switching means so that only one of the reference electrodes is always connected to the drive means.
Specification