All common display technologies are designed to be reversible, in that the written information can be erased and re-written many times. This attribute is core to most display technologies, but not all – in fact, for some applications a write-once display that permanently displays the written data is a requirement.
One such application is disposable medical diagnostic devices in which the test result needs to be kept as a permanent record. In line with many other applications, low cost and minimum environmental impact are significant advantages in this area.
CIT has developed a patent pending flexible, write-once display utilizing its core digital metallization technology. This display is constructed from two laminated PET films that have thin films of copper deposited. Data is displayed by applying a small voltage across the films, resulting in removal of copper from the front film to give the high-contrast image. This written data is inviolable and so the whole display, in case of the medical device, can be removed from the device and used as a permanent record of the result.
This technology has now passed the proof of concept stage and processes for large-scale production are currently under development.