The present invention relates to OLED flat-panel display systems composed of multiple stacked tiles.
Electronic display systems are commonly used to display information from computers. Typical display systems range in size from small displays used in mobile devices to very large displays visible to thousands of viewers. Large displays are sometimes created from tiling smaller display devices together. For example, video walls using multiple video displays are frequently seen in the electronic media and flat-panel displays are tiled to create larger displays. Multiple projector systems used to create a large, tiled, high-resolution display are also available.
Tiled displays are well known in the prior art. For example, U.S. Pat. No. 6,683,665B1 issued Jan. 27, 2004 describes tile structures wherein each tile has a display portion and an electronics portion. The tiles are fastened together into an array with the use of a frame. Alternatively, U.S. Pat. No. 6,498,592 issued Dec. 24, 2002 describes the use of a single substrate with electrical devices and a display. However, as disclosed, these designs require the use of vias through the electronics substrates and are problematic for displays requiring a hermetic seal for the display components, for example in an OLED display. Vias in glass substrates are difficult to construct and the use of alternative substrates are not well suited to sealing the display materials. Moreover, the design requires an additional frame and is not well suited to roll-to-roll manufacturing.
Another technique that relies on overlapping the display tiles is described in WO 03/042966 published May 22, 2003 entitled “Display for a Large Panel Display Consisting of Tiled Displays”. This method uses a complex support structure and a plurality of printed circuit boards. Moreover, tile seams may be visible when the display is viewed off angle.
There is a need therefore for an improved tiled display system that overcomes the problems noted above.
In accordance with one aspect of the present invention there is provided a tiled OLED display structure, comprising:
a) one or more first OLED tiles having a substrate with a first display area with spaced-apart electrodes and at least one layer of organic light-emitting material between the spaced apart electrodes and a non-display area with conductors for electrically connecting the spaced-apart electrodes in the display area to a connection point at the edge of the display substrate, the spaced apart electrodes producing light-emitting pixel elements when subjected to a current; and
b) one or more second OLED tiles having a substrate with a second display area with spaced-apart electrodes and at least one layer of organic light-emitting material between the spaced apart electrodes stacked above the non-display area of another OLED tile substrate and in registration with the other first display area, the spaced apart electrodes of the second display area producing light-emitting pixel elements when subjected to a current.
In accordance with another aspect of the present invention there is provided a tiled display structure, comprising:
a) one or more first light emitting tiles having a substrate with a first display area with spaced-apart electrodes and at least one layer of light-emitting material between the spaced apart electrodes and a non-display area with conductors for electrically connecting the spaced-apart electrodes in the display area to a connection point at the edge of the display substrate, the spaced apart electrodes producing light-emitting pixel elements when subjected to a current; and
b) one or more second light emitting tiles having a substrate with a second display area with spaced-apart electrodes and at least one layer of light-emitting material between the spaced apart electrodes stacked above the non-display area of another tile substrate and in registration with the other first display area, the spaced apart electrodes of the second display producing light-emitting pixel elements when subjected to a current.
The present invention has the advantage that the tiled display utilizes very simple electrical interconnections, does not require substrate vias, is simple to manufacture in a continuous process, and has improved yields.
These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims and by reference to the accompanying drawings.
The above and other objects, features, and advantages of the present invention will become more apparent when taken in conjunction with the following description and drawings wherein identical reference numerals have been used, where possible, to designate identical features that are common to the figures, and wherein:
a is a perspective view of a display substrate with a plurality of registered display area/tiles of
b is a perspective view of a single display area according to one embodiment of the present invention on a supporting substrate;
a is a perspective view of the display substrate of
b is an enlarged partial top view of
The layers of the Figures are not to scale, since the differences in size of the elements in the Figures are too great to permit depiction at scale.
Referring to
As shown in
The display 10 may be encapsulated with a single encapsulating cover (not shown) affixed with an adhesive to the display substrate 12. Alternatively, each OLED display tile may be separately encapsulated with its own cover. In either case, allowance must be made for the conductors or any connecting cables to pass under or through the cover. Preferably, the encapsulating cover(s) are very thin to minimize the thickness of the overall display. In particular, coated encapsulating covers comprising a thin, conformal coating located over the top spaced-apart electrode are preferred.
The next step in the manufacture of display 10 is illustrated by
Referring to
Referring to
Referring to
The electrodes 16, 24, 44, and 54 all extend beyond the edges of tile layers so that space is provided for connecting electrical cables to the electrodes. Alternatively, drivers themselves may be located on the edges of the tiles. Each OLED tile 20, 40, 50, and the display areas 14, 22, 42, 52 on the display substrates may be driven identically and separately, thereby enabling larger displays. Each OLED tile 20, 40, and 50 may be separately encapsulated with a cover as is known in the art or the entire display structure 10 may be encapsulated under one larger cover.
The substrates 20 and 40 have a similar size, although the orientation of half of the substrates is a mirror image of the other half of the substrates. This similar size and symmetry reduces manufacturing costs. The substrates 46 must be slightly smaller than the substrate 26 to allow the conductors 24 to extend beyond the substrate 46 to allow connectors to be connected to a controller. Likewise, the support tiles 30 have a similar size to the OLED tiles 50, although the OLED tile 50 must be slightly smaller in one dimension than the substrate 46 to allow the conductors 44 to extend beyond the substrate 56.
The display areas 14, 22, 42, and 52 are identical and may be constructed using common deposition and masking techniques, as are well known in the OLED art. Each OLED tile may be tested individually before assembly onto the display substrate 12, thereby improving yields in the final, assembled display.
In operation, power is provided by controllers (not shown) through the electrodes 16, 24, 44, and 54 to cause a current to flow through the OLED materials in the pixels 15 of the display area of each tile. The current causes each pixel 15 to light up as controlled. The control and operation of OLED devices is well known in the art.
The present invention has been described in an embodiment including 16 tiles in a four-by-four array. Other arrangements are possible. For example, a three-by-three array can be formed by locating a single central display area 14 in the center of a display substrate 12, positioning four identical OLED tiles 20 around the periphery of, and in registration with, the display area 24 on the display substrate 26. Four corner tiles 50 can be located above the non-display areas of OLED tiles 20 to form a complete, rectangular array. Likewise, larger displays of, for example, 25 tiles in a five-by-five array may be made. In each arrangement, successive stacked layers of OLED tiles with support tiles positioned between them as necessary can form a contiguous array 64 of display areas.
Because of the stacked tile arrangement, the display substrate 12 may be very large, for example, a square meter or larger. In an alternative embodiment it is possible to locate an initial OLED tile over the center of the display substrate 12 so that OLED materials and electrodes do not need to be deposited on the display substrate. For example, an OLED tile of one quarter the size of the display substrate 12 may be positioned on each quadrant of the display substrate to form a support for subsequent layers of OLED tiles and support tiles.
Alternatively, the support tiles may be integrated into the OLED tiles so that the tile substrate is larger than shown. In this case, the non-display areas are located over underlying display areas.
The present invention may be manufactured in a continuous manufacturing process wherein the display and tile substrates are made on a continuous web. Once manufactured, the substrates may be singulated and assembled. The use of a stacked tile structure removes any need for vias in a substrate or connections between tiles, thereby improving encapsulation, improving reliability, and reducing costs of manufacturing.
In a preferred embodiment, the present invention is employed in a tiled flat-panel array of OLED display devices composed of small molecule or polymeric OLEDs as disclosed in but not limited to U.S. Pat. No. 4,769,292, issued Sep. 6, 1988 to Tang et al., and U.S. Pat. No. 5,061,569, issued Oct. 29, 1991 to VanSlyke et al. Many combinations and variations of organic light-emitting displays can be used to fabricate such a device.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.