Segmented print bar for large-area OVJP deposition
OVJP print bars are provided that include multiple print head segments, each of which includes a print head and which can be positioned relative to the substrate independently of each other print head segment. Accordingly, a more consistent head-to-substrate distance can be maintained even for substrates that are not uniformly planar.
1. A print bar for organic vapor jet (OVJP) deposition, the print bar comprising:
a plurality of print head segments, each of the plurality of print head segments comprising an OVJP print head;
a plurality of fly height distance sensors, each of the plurality of fly height distance sensors configured to measure a distance between a substrate disposed below the print bar and a portion of at least one of the print head segments; and
a plurality of actuators configured to adjust a position and/or orientation of one or more of the plurality of print head segments based upon one or more distances between the substrate and the print bar measured by one or more of the plurality of fly height distance sensors.
2. The print bar of claim 1 , wherein the plurality of print head segments are arranged in two rows in a direction essentially perpendicular to a direction of motion of the print bar relative to the substrate when the print bar is operated to deposit material on the substrate.
3. The print bar of claim 2 , wherein the plurality of print head segments are disposed within the rows such that print areas of each row of corresponding OVJP print heads form a single printed column on the substrate when the print bar is operated to deposit material on the substrate.
4. The print bar of claim 1 , wherein each OVJP print head comprises an OVJP deposition nozzle in fluid communication with a carrier gas source and an organic material vapor source.
5. The print bar of claim 1 , wherein each actuator of the plurality of actuators is connected to, and configured to control the position and/or orientation of, at least two of the plurality of print head segments.
6. The print bar of claim 5 , wherein each of the plurality of actuators controls the position and/or orientation of the at least two of the plurality of print head segments based upon distance measurements obtained by two or more of the plurality of fly height sensors.
7. The print bar of claim 5 , wherein each of the plurality of actuators controls the position and/or orientation of the at least two of the plurality of print head segments based upon a distance measurement obtained by at least one of the at least one fly height sensor.
8. The print bar of claim 1 , wherein each print head segment of the plurality of print head segments is movable independently of each other print head segment of the plurality of print head segments.
9. The print bar of claim 8 , wherein each print head segment is movable at least in a direction essentially normal to the substrate independently of each other print head segment such that the distance from the each print head segment to the substrate is adjustable independently of the distance from each other print head segment to the substrate.
10. The print bar of claim 1 , further comprising one or more gas channels arranged to transport organic material and/or carrier gas to the plurality of print head segments.
11. The print bar of claim 1 , further comprising one or more vacuum channels arranged to remove material from a region between the print bar and the substrate when the print bar is operated to deposit material on the substrate.
12. The print bar of claim 1 , further comprising a cold plate disposed adjacent to a plurality of the print head segments.