"Epitaxial (Epi) Film Bonding" is a technology developed for LED printer printheads. It enables thin films of dissimilar materials to be released and to be bonded to each other by using the intermolecular bonding force working between the films. Using this method reduces the number of wire bondings to about 1/5th of what was required previously. See video animation on this page.

OKI Printing Solutions was the first to practically apply this technology to printer LED heads. Essentially, this creates a new type of device that integrates a light-emitting device (LED) and a driver circuit (IC) into a single unit. The new application has a positive impact on the environment because of the decrease of resources used, miniaturization and a reduction in power consumption.

With Epi Film Bonding, we can obtain about twice as much light from the new LEDs as compared to ordinary LEDs. This is due to the fact that, while the LEDs normally radiate light into all directions, new LEDs only allow the effective use of the light radiated towards the top of the chip. Additionally, Epi Film Bonding allows a reflective layer to be placed on the driver IC. This essentially translates into a doubling of the effective light reflected outwardly (see diagram).