Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2001-11-26
2003-07-08
Mayes, Curtis (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C118S720000, C118S721000, C118S504000, C118S505000
Reexamination Certificate
active
06589382
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the deposition of organic material through a mask onto a substrate in the process of making an organic light emitting diode (OLED).
BACKGROUND OF THE INVENTION
In the making of organic light emitting devices (OLED) there are a number of steps in which organic layers are deposited on or over a substrate. It is essential that a deposition mask be aligned and properly mounted so that accurate deposition takes place. The deposition mask is typically a precision mask made of a magnetic material and is thin and malleable. The deposition mask is lithographically patterned and because it is thin permits the appropriate thickness of organic material to be deposited on or over the substrate. The maximum size of a single piece depositions mask is limited by manufacturing process limitations, specifically dimensional accuracy and overall size. Another limitation of the present technology is the inability to replace damaged areas of the deposition mask. The deposition mask manufacturing process is subject to error and the increase in size and complexity of a mask design account for lower yield when manufacturing deposition masks. There is a need for more accurate, larger format precision deposition mask. There is also a need for a method of replacement of defective areas of the deposition mask.
SUMMARY OF THE INVENTION
It is an object of the present invention to increase the throughput of forming OLED devices which use deposition masks.
It is a further object of the present invention to provide a structure which will permit the simultaneous formation of organic layers of an OLED device through different mask segments.
These objects are achieved in alignment device for permitting a deposition mask having a plurality of mask segments to be positioned relative to a substrate to facilitate simultaneous deposition of organic material on to the substrate which will be part of an organic light emitting device, comprising:
(a) a base having a first set of alignment pins and a second set of alignment pins;
(b) a plate secured to the base;
(c) a frame having an opening aligned with the plate, the frame being formed with a first set of alignment pin receiving holes corresponding to the position of the first set of pins so that the frame is removably mounted to the base;
(d) a plurality of mask segments positioned on the plate to define the deposition mask;
(e) a transparent flat plate contacting the second set of alignment pins and the deposition mask and being sized to expose segments of the deposition mask;
(f) means for securing the mask segments to each other; and
(g) means for securing the deposition mask to the frame.
These objects are also achieved by A method of aligning a plurality of masks segments to form a mask which permits a more effective manufacture of organic light emitting diode devices, comprising the steps of:
(a) providing a base having a first and second set of alignment pins and securing a plate to the base;
(b) providing a frame having an opening aligned with the plate and formed with a first set of alignment pin receiving holes;
(c) aligning the frame and base by positioning the first set of alignment pins in the first set of alignment pin receiving holes;
(d) positioning the plurality of mask segments on the plate;
(e) providing a transparent flat plate aligned with the second set of alignment pins on the plurality of mask segments, such transparent flat plate having fiducial marks;
(f) positioning the mask segments to be properly aligned with the fiducial marks and securing the mask segments to the frame; and
(g) bonding the plurality of mask segments to provide a stitched mask with each mask segment being adapted to be used in the deposition of organic material on a single substrate.
It is a feature of the present invention that by mounting and securing mask segments a stitched mask can be produced that provides improved dimensional accuracy of a deposition mask having the ability to remove and replace mask sections. The present invention makes possible the manufacture of a larger format deposition mask. The mask sections can be attached to each other using a removable adhesive and will be mounted to a frame.
An advantage of the present invention is that the deposition mask sections can be accurately assembled and mounted to a frame that is then positioned relative to the substrate. Deposition mask sections can be stitched together to make a mask assembly larger than is capable with single piece deposition mask. A stitched mask can be disassembled to allow for removal of defective deposition mask sections. The mask sections can then be replaced. A stitched deposition mask being made up of small sections are less expensive to produce. Stitched masks have greater life expectancy, being repairable. A stitched deposition mask is assembled having greater accuracy than present process. This approach will improve yield and make possible deposition of larger substrates.
REFERENCES:
patent: 4676193 (1987-06-01), Martin
patent: 6146489 (2000-11-01), Wirth
patent: 6475287 (2002-11-01), Clark
patent: 2002/0102754 (2002-08-01), Fujimori et al.
Clark Thomas K.
Rajeswaran Gopalan
Eastman Kodak Company
Mayes Curtis
Owens Raymond L.
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