Patent ID: 7214554

Claim:
A method for making an OLED device having a plurality of organic layers, comprising: a) providing a substrate having a plurality of test regions and one or more device regions wherein the plurality of test regions are spaced apart from the one or more device region; b) moving the substrate sequentially into first and second deposition chambers for respectively depositing first and second different organic layers of the OLED device in each deposition chamber; c) depositing the first organic layer in the first deposition chamber onto a device region through a first opening in a first shadowmask and onto a first test region through a second opening in the first shadowmask and depositing the second organic layer onto the device region through a first opening in a second shadowmask and onto a second test region through a second opening in the second shadowmask wherein the first test region is spaced apart from the second test region; d) measuring a property of each organic layer in the first and second test regions; and e) adjusting the deposition process of either the first or second organic layer or both in accordance with the measured property.