TEMPORARY ARC INDUCEMENT OF GLASS SUBSTRATE DURING DIFFUSIVE TRANSPORT DEPOSITION
Apparatus for vapor deposition of a sublimated source material as a thin film on a photovoltaic module substrate is generally provided. The apparatus can include a deposition head; a distribution plate disposed below said distribution manifold and above an upper surface of a substrate transported through said apparatus and defining a pattern of passages therethrough; and, a carrying mechanism configured to transport the substrate in a machine direction under the distribution plate such that an upper surface of the substrate defines an arc in a cross-direction that is substantially perpendicular to the machine direction. Processes are also generally provided for vapor deposition of a sublimated source material to form thin film on a photovoltaic module substrate.
1 . An apparatus for vapor deposition of a sublimated source material as a thin film on a photovoltaic module substrate, said apparatus comprising:
a deposition head;
a distribution plate disposed below said distribution manifold and above an upper surface of a substrate transported through said apparatus, wherein the distribution plate defines a pattern of passages therethrough; and,
a carrying mechanism configured to transport the substrate in a machine direction under the distribution plate such that an upper surface of the substrate defines an arc in a cross-direction that is substantially perpendicular to the machine direction.
2 . The apparatus as in claim 1 , wherein the arc is concave such that each lateral edge on the upper surface of the substrate is above a middle portion of the upper surface of the substrate.
3 . The apparatus as in claim 2 , wherein the substrate defines a thickness, and wherein the arc has a height defined by the distance from one lateral edge to the middle portion in a z-direction that is perpendicular to both the machine direction and the cross-direction, the height being greater than the thickness of the substrate.
4 . The apparatus as in claim 2 , wherein the pattern of passages is configured to provide greater resistance to the flow of sublimated source vapors at its lateral ends than a middle section.
5 . The apparatus as in claim 4 , wherein the pattern of passages defines holes in the middle section that are larger than holes along the lateral edges.
6 . The apparatus as in claim 4 , wherein the pattern of passages defines a hole gradient in the cross-direction such that more holes are located in the middle section that along the lateral edges.
7 . The apparatus as in claim 2 , wherein the carrying mechanism is configured to support the substrate only along its lateral edges.
8 . The apparatus as in claim 7 , wherein the substrate has a width defined between its lateral edges, wherein the width is about 50 cm to about 1 meter.
9 . The apparatus as in claim 2 , wherein the arc has a height defined by the distance from one lateral edge to the middle portion in a z-direction that is perpendicular to both the machine direction and the cross-direction, the height being greater than the thickness of the substrate, and wherein the substrate is supported between its lateral edges to control the arc height.
10 . The apparatus as in claim 9 , wherein the substrate has a width defined between its lateral edges, wherein the width is about 1 meter to about 3 meters.
11 . The apparatus as in claim 1 , wherein the arc is convex such that each lateral edge on the upper surface of the substrate is below a middle portion of the upper surface of the substrate.
12 . The apparatus as in claim 11 , wherein the arc has a height defined by the distance from one lateral edge to the middle portion in a z-direction that is perpendicular to both the machine direction and the cross-direction, and wherein the height is greater than a thickness in the z-direction of the substrate.
13 . The apparatus as in claim 11 , wherein the pattern of passages is configured to provide greater resistance to the flow of sublimated source vapors in its middle section than along its lateral ends.
14 . The apparatus as in claim 13 , wherein the pattern of passages defines holes in the middle section that are smaller than holes along the lateral edges.
15 . The apparatus as in claim 13 , wherein the pattern of passages defines a hole gradient in the cross-direction such that less holes are located in the middle section that along the lateral edges.
16 . The apparatus as in claim 1 , wherein the distribution plate is shaped to be substantially parallel to the arc defined by the substrate.
17 . A process for vapor deposition of a sublimated source material to form thin film on a photovoltaic module substrate, the process comprising:
sublimating a source material within a deposition head;
conveying individual substrates in a machine direction under a distribution plate on the deposition head such that an upper surface of the substrate defines an arc in a cross-direction that is substantially perpendicular to the machine direction; and,
distributing the sublimated source material through a pattern of passages defined in the distribution plate and onto the upper surface of the substrates.
18 . The process as in claim 17 , wherein the arc is concave such that each lateral edge on the upper surface of the substrate is above a middle portion of the upper surface of the substrate.
19 . The process as in claim 18 , wherein the pattern of passages is configured to provide greater resistance to the flow of sublimated source vapors at its lateral ends than a middle section.
20 . The process as in claim 18 , further comprising:
transporting the substrates through a heating apparatus and under the distribution plate to heat the substrates to a deposition temperature, wherein the substrates are initially substantially planar such that upon heating the substrates are deformed to define the arc.