Patent Publication Number: US-2002008463-A1

Title: Display device and module therefor

Description:
[0001] This Application claims the benefit of U.S. Provisional Application Ser. No. 60/213,568 filed Jun. 22, 2000. 
    
    
     
       [0002] The present invention relates to a display and, in particular, to a display and an electrical module therefor.  
       [0003] It has long been desired that electronic displays be made with larger screen sizes and also be very thin, ultimately reaching a configuration that may be hung on a wall. Inherent physical limitations preclude conventional cathode ray tubes, such as the color picture tubes and display tubes utilized in televisions, computer displays, monitors and the like, from achieving such desired result. While plasma displays have been proposed to satisfy such desire, the large glass vacuum envelope they require is both heavy and expensive, which is not desirable.  
       [0004] The entire display screen of plasma displays must be fabricated as a single unit and must reproduce many thousands of picture elements or “pixels.” Any significant defect that results in faulty pixels or in a non-uniform brightness across the screen, even if confined to a relatively small area, renders the entire screen defective. Such defects cannot be tested or detected until the entire screen is processed, and are either not susceptible of repair or are very expensive to repair, thereby substantially reducing the yield and increasing the cost of each satisfactory plasma display.  
       [0005] One attractive approach for producing a large, thin display screen is to provide an array of a large number of adjacent light-emitting fibers. An advantage of such light-emitting fiber display is that each fiber is relatively inexpensive and may be separately tested before assembly into a display. Because defective fibers are detected and discarded before assembly into a display, the yield of a display which is made from known good light-emitting fibers is increased and the cost thereof is reduced. One such fiber display is described in published PCT Application WO 00/51192 entitled “DISPLAY DEVICE.” 
       [0006] With regard to such fiber-based displays, it is desirable that the light-emitting fibers therefor be connected reliably and inexpensively, e.g., in a way that provides suitable performance, facilitates assembly of fibers into a display, and/or reduces cost. This is particularly of interest because two connections must be made to each pixel via conductors referred to as “select lines” and data lines” which typically lie in substantially orthogonal directions, one in the direction of the side-by-side fibers and the other transversely with respect to the side-by-side light-emitting fibers.  
       [0007] In the arrangement of WO 00/51192, a large multi-layer circuit substrate or printed circuit board  210  (FIGS. 3 and 4) is substantially the same size as the viewing screen of the display  10  and is connected to the light-emitting fibers  100  by conductive bump connections  232 . The fabrication of such large substrate is likely to be complex and possibly costly, as may be the alignment and connection of such substrate to the fibers. In addition, a large one-piece circuit substrate departs from some of the benefits of a modular display as set forth therein.  
       [0008] WO 00/51192 also describes a flexible circuit board  360  suitable for a display module  310  (FIGS. 8, 9A and  9 B) to facilitate assembly of flexible circuit boards into modules for a display. Electronic circuits employing a flexible printed circuit substrate or a combination of a rigid printed circuit board and a flexible cable tend to be more expensive than conventional rigid circuit boards.  
       [0009] Accordingly, there is a need for an improved arrangement for connecting light-emitting fibers, and desirably one that is easily aligned and low in cost  
       [0010] To this end, the display of the present invention comprises a plurality of fibers disposed in side-by-side array and each having a plurality of light-emitting elements disposed on a first surface thereof and a length, each light-emitting element having first and second electrodes, wherein the first electrodes are electrically connected to a first contact on the first surface proximate an end of each the fiber and wherein the respective second electrodes are connected to respective second contacts proximate the corresponding light-emitting element, wherein the respective first contacts of the plurality of side-by-side fibers are at different positions with respect to each other relative to the lengths of the fibers. A circuit board having first and second pluralities of elongated conductors disposed in respective substantially parallel side-by-side arrangement is disposed proximal the plurality of side-by-side fibers with the first and second pluralities of elongated electrical conductors disposed substantially transverse to the lengths of the fibers, wherein each of the first plurality of elongated conductors is electrically connected to the first contact of a predetermined one of the plurality of fibers and wherein each of the second elongated conductors is electrically connected to the second contacts of corresponding light-emitting elements of each of the plurality of fibers. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
     [0011] The detailed description of the preferred embodiments of the present invention will be more easily and better understood when read in conjunction with the FIGURES of the Drawing which include:  
     [0012]FIG. 1 is a perspective view schematic diagram of an exemplary embodiment of a display including a circuit board and light-emitting fibers and illustrating the arrangement thereof in accordance with the invention;  
     [0013]FIGS. 2A, 2B and  2 C are a bottom view, a side view and an end view schematic diagram, respectively, of the exemplary embodiment of a display of FIG. 1;  
     [0014]FIGS. 3A and 3B are schematic diagrams illustrating alternative exemplary arrangements of a light-emitting fiber including the plurality of lightemitting elements disposed on one surface thereof, useful in the display of FIGS. 1 and 2A- 2 C;  
     [0015]FIGS. 4A through 4C are schematic diagrams illustrating steps in the assembly of an exemplary display of a light-emitting fiber display including the electronic circuit of FIG. 1;  
     [0016]FIG. 5 is a schematic diagram of an embodiment of a display employing a compressible spacer in accordance with the invention;  
     [0017]FIG. 6 is a plan view schematic diagram of an exemplary display in accordance with the invention with the circuit module cut away to show certain connections therein;  
     [0018]FIG. 7 is a plan view schematic diagram of an alternative arrangement of the display of FIG. 6 showing certain alternative connections thereof;  
     [0019]FIG. 8 is a plan view schematic diagram of an alternative arrangement of the display of FIG. 7;  
     [0020]FIG. 9 is a rear plan view schematic diagram of an exemplary light-emitting display including a plurality of the displays of FIG. 1;  
     [0021]FIGS. 10A and 10B are a side view and an end view schematic diagram, respectively, of the exemplary light-emitting display of FIG. 9; and  
     [0022]FIGS. 11A and 11B are cross-sectional views taken along cross-section lines  11 A- 11 A and  11 B- 11 B, respectively, in FIG. 6.  
     [0023] In the Drawing, where an element or feature is shown in more than one drawing figure, the same alphanumeric designation may be used to designate such element or feature in each figure, and where a closely related or modified element is shown in a figure, the same alphanumerical designation primed may be used to designate the modified element or feature. It is noted that, according to common practice, the various features of the drawing are not to scale, and the dimensions of the various features are arbitrarily expanded or reduced for clarity. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0024] A plurality of light-emitting fibers  200 , i.e. fibers each having a plurality of light-emitting elements disposed along its length, are arrayed in side-by-side array, preferably being substantially contiguous, and are connected to appropriate electrical driver circuits for selectively and controllably energizing each light-emitting element or picture element (pixel) to produce a light-emitting display  10  for displaying an image or information. Image and/or information are used interchangeably with respect to what is displayed on a display device, and are intended to encompass any and all of the wide variety of displays that a user may desire, including, but not limited to, visual images and pictures, whether still or moving, whether generated by a camera, computer or any other source, whether true, representative or abstract or arbitrary, whether or not including symbols or characters such as alphanumeric characters or mathematical notations, whether displayed in black and white, monochrome, polychrome or color.  
     [0025] A light-emitting fiber  200  is fabricated, for example, on a fiber of an optically transmissive material, such as glass, borosilicate glass, soda-lime glass, quartz, sapphire, plastic, polymethyl-methacrylate (PMMA), polycarbonate, acrylic, Mylar, polyester, polyimide or other suitable material, to have along its length on one of its surfaces a plurality of light-emitting elements or picture elements (pixels)  280 . Lightemitting elements  280  include an electro-luminescent material, preferably an Organic Light-Emitting Diode (OLED) material, disposed between suitable electrodes. Each light-emitting element or OLED “stack” includes a hole-injecting electrode, one or more layers of one or more OLED materials and an electron-injecting electrode, and is independently operable to produce one pixel of the image or information to be displayed. In a color display, three physical pixel elements may each produce one of three color sub-pixels that emit light of three different colors that together produce one color pixel of a color image.  
     [0026] Each light-emitting fiber includes a conductor along its length for applying select signals to each of the light-emitting elements disposed along the length of that fiber. Each light-emitting fiber also includes a plurality of contacts along its length, one contact for each light-emitting element, to which conductors providing pixel data signals are connected. Such data signal conductors lie transverse to the length direction of the light-emitting fibers for interconnecting such fibers in an array of a light-emitting display, as described herein.  
     [0027] Thus, suitable electrical connections can be made to couple the select signal and the data signal to respective electrodes of each light-emitting element for controllably and selectively energizing each light-emitting element to produce the pixels of an image to be displayed by a light-emitting display including a plurality of light-emitting fibers in parallel side-by-side array. These connections are made to the surface of the light-emitting fibers on which the light-emitting elements are formed, and the light emitted thereby passes through the optical fiber away from the lightemitting elements to be observed by a viewer of such display.  
     [0028] It is noted that because the light-emitting fibers may be of any desired length, and because any desired number of such fibers may arrayed side-by-side, a thin panel display of virtually any desired size (height and width) may be assembled utilizing the present invention.  
     [0029] An exemplary optical fiber is typically about 0.25 mm (about 0.010 inch) wide, and has light-emitting elements disposed along its length on a pitch of about 0.75 mm (about 30 mils). Where the light-emitting fibers are utilized in a color display, light-emitting elements emitting three different colors of light, such as red (R), green (G) and blue (B), are utilized. The three different color light-emitting elements are arranged to be in adjacent sets of R, G, B elements, each set providing a color pixel. Such arrangement of light-emitting elements may be provided by sequencing R, G and B OLED materials along the length of each light-emitting fiber or may be provided by placing fibers of different colors side-by-side in an R-G-B sequence, i.e. a red-emitting fiber next to a green-emitting fiber next to a blue-emitting fiber, and so forth. Typical light-emitting fibers are described, for example, in published PCT Application WO 00/51192 entitled “DISPLAY DEVICE” and in U.S. patent application Ser. No. 09/691,882 entitled “LIGHT-EMITTING FIBER, AND METHOD FOR MAKING SAME” filed Oct. 19, 2000.  
     [0030]FIG. 1 is a perspective view schematic diagram of an exemplary embodiment of a display module  10  including a circuit board  100  and light-emitting fibers  200  and illustrating the arrangement thereof in accordance with the invention. Circuit board  100  includes a first portion  110  and a second portion  130  that are positioned at about a right angle to each other, although a greater or lesser angle could be utilized. First portion  110  of circuit board  100  has edge connections  112 ,  114 ,  116  at which printed conductors  142 ,  144  are arrayed for being engaged by a conventional edge connector (not shown) through which electrical signals are provided to and received from the electronic circuits on circuit board  100 . Electronic devices  150 , such as integrated circuits, hybrid circuits electronic circuit modules and the like, are mounted to first portion  110  for operating on the signals received via edge connections  112 ,  114 ,  116  and for providing drive signals, such as select signals and/or data signals, to light-emitting fibers  200 .  
     [0031] Second portion  130  of circuit board  100  includes electrical conductors  140 ,  142  on one side thereof through which signals, e.g., data signals via conductors  140  from electronic devices  150  and select signals via conductors  142  from edge connections  112 ,  116 , are applied to plural light-emitting fibers  200  that are arrayed side-by-side. Conductors  144  couple drive signals from edge connection  114  to electronic device  150 . The surface  202  of light-emitting fibers  200  from which light is emitted faces away from second portion  130  of circuit board  100 . For example, conductive “dots”  145 , such as small drops of solder or electrically conductive epoxy may be applied to the contacts of the light-emitting elements of fibers  200 , or to conductors formed across several fibers in a direction transverse to the length thereof, and the second portion  130  of circuit board  100  positioned thereagainst for connecting ones of conductors  140  on second portion  130  to the contacts of fibers  200 . Fibers  200  include a contact at one or both ends thereof for receiving a second signal or select signal, and conductors  142  on circuit board  100  connect thereto by like conductive dots  146 . Thus, signals from electronic devices  150  are applied to ones of the light-emitting elements of side-by-side arrayed fibers  200  to display information. Circuit board  100  together with the side-by-side array of light-emitting fibers  200  provide a light-emitting display or display module  10 .  
     [0032] First portion  110  and second portion  130  are maintained in the desired relative positions by a fillet of epoxy  120  along the inside comer formed where the two portions  110 ,  130  meet. The structure thus formed is in effect a beam having an Lshaped cross-section and so is quite rigid, especially in the longer dimension, thereby to provide substantial support to the light-emitting fibers  200 . Display module  10  is also advantageous because circuit board  100  supports light-emitting fibers  200  so as to facilitate the placement of fibers  200  as modules  10  in close proximity on a common faceplate, thereby to provide a light-emitting display comprising a plurality of light-emitting display modules  10 . Desirably, such arrangement may be utilized to provide a display that is economical, reliable and rugged.  
     [0033] Electronic drive circuit  150  is, for example, an integrated circuit, hybrid circuit, microelectronic circuit or other electronic device that produces drive signals, such as data drive signals and/or select drive signals, to be applied to the data and/or select electrodes of the light-emitting elements of the fibers  200 . Patterned conductors  140 ,  142  are preferably in substantially parallel spaced-apart relationship at the end of second portion  130  of circuit substrate  100  distal driver circuit  150  and proximal fibers  200  to which they are attached.  
     [0034] More particularly, patterned conductors  140 ,  142  are preferably substantially parallel and spaced apart at like pitch to the spaced-apart corresponding contacts of fibers  200 , thereby providing conductors  140 ,  142  that facilitate a direct and simple interconnection between ones of the patterned conductors  140 ,  142  of electronic circuit  100  and the corresponding contacts of fibers  200 .  
     [0035] Circuit board  100  can be tested, either fully or to any desired degree, prior to assembly to light-emitting fibers  200 . Thus, any inoperative function or out of specification condition can be identified and rectified at a lower assembly level, before circuit board  100  is assembled to any light-emitting fibers  200  and the cost of troubleshooting and repair, or of scrapping the item, is much greater.  
     [0036] An exemplary circuit board  100  was made of 0.060 inch (about 1.5 mm) thick fiberglass/epoxy material (e.g., FR4) with 0.001 inch (about 0.025 mm) thick copper conductors that were solder tinned. The conductors were 0.010 inch (about 0.25 mm) wide and separated by 0.18 inch (about 4.5 mm) wide spaces. A 90° V-shaped groove was made in the circuit board, but not severing the printed circuit conductors thereon, and the circuit board was bent 90° and secured with a five-minute curing commercial epoxy without damage to the bent copper conductors, as determined by visual inspection and electrical continuity testing.  
     [0037] It is noted that the second portion  130  of circuit board  100  preferably includes only the conductors  140 ,  142  that will be attached to contacts on light-emitting fibers  200  by electrically-conductive adhesive or low-temperature solder, i.e. the data signal conductors and the select signal conductors, and so the second portion  130  of circuit board  100  may have only a “single-sided” conductor pattern. The first portion  110  of circuit board  100  may have a “single-sided” or a “double-sided” conductor pattern as is convenient. Conductors  118  between edge connections  114 , for example, and electronic devices  150  may include connections between conductors on the two opposing surfaces of circuit board  100  for providing cross overs and the like, as may be necessary or convenient. Conventional edge connectors are available for connecting to either “single-sided” or “double-sided” conductor patterns.  
     [0038]FIGS. 2A, 2B and  2 C are a bottom view, a side view and an end view schematic diagram, respectively, of the exemplary embodiment of a display module  10  according to FIG. 1. Display module  10  comprises a bent electronic circuit board  100  having a plurality of electronic devices  150  on the first portion  110  thereof and having a plurality of light-emitting fibers  200  attached to the second portion  130  thereof. The surface  202  of light-emitting fibers  200  from which light is emitted faces away from second portion  130  and together provide a viewing surface  12  on which a viewer may observe the information displayed. The plurality of light-emitting fibers  200  are attached to the second portion  130  by a plurality of conductive dots  145 ,  146 . Conductive dots  145 ,  146  connect ones of data bus conductors  140  and select bus conductors  142  of circuit board  100  to corresponding ones of the contacts of plural fibers  200 .  
     [0039] Display module  10  includes plural light-emitting fibers  200  arrayed in parallel side-by-side arrangement and an electronic circuit board  100  coupled thereto for providing electrical drive signals, such as select signals and/or data signals, for the light-emitting elements thereon. The array of side-by-side fibers  200  may include compressible spacers  315  between ones of fibers  200 , as described below.  
     [0040] This arrangement advantageously provides for convenient positioning of circuit boards  100  in modules  10  with tolerance being important only in the direction transverse to conductors  140 ,  142 . In addition, adjacent modules  10  do not interfere, even if certain components of a particular module such as devices  150  extend beyond the edges of that module  10 .  
     [0041]FIGS. 3A and 3B are schematic diagrams illustrating alternative exemplary arrangements of light-emitting fiber  200  including the plurality of lightemitting elements  280  disposed on one surface thereof. Only a portion of fiber  210  and/or light-emitting fiber  200  is shown in FIGS.  3 A- 3 B which each include a top view, a side view and an end view or cross-sectional view. Fiber  210  or other elongated member of an optically transmissive material has a thin layer of optically transmissive, electrically-conductive material  220  on the top surface  212  thereof. Conductive layer  220 , such as indium tin oxide (ITO), tin oxide, zinc oxide, a noble metal, combinations thereof, or another transparent hole-injecting material, serves as the hole injecting electrode of a later completed OLED light-emitting element or stack  280 .  
     [0042] An electrically conductive bus  230 , preferably of a highly conductive metal such as aluminum, copper, gold, chromium/gold (Cr Au) or silver, is deposited on or attached to one side  216  of optical fiber  210  and slightly overlaps the ITO  220  either on top surface  212  or on side surface  216 . Conductive bus  230  makes electrical contact to ITO layer  220  for providing an electrical connection of relatively high electrical conductivity between the portion of hole injecting electrode  220  associated with each light-emitting element  280  and an input contact  290  at one or both ends  218  of optical fiber  210 .  
     [0043] Particularly in large displays, the lengths of conductor  230  may become long and the resistance of a thin-film or other deposited conductor  230  may be higher than desired. Conductor  230  may be made thicker than the thicknesses obtainable by vacuum deposition of metals such as by attaching thin strips  230 ′ of metal foil (e.g., 25-50 μm thick) along the length of fiber  210  and connected at intervals or continuously to ITO layer  220  by a spot or line of electrically-conductive epoxy or adhesive. Such strips  230  may be of aluminum, copper, silver, gold or other suitable metal, and may be in place of or in addition to the deposited strips  230 , and may be embossed so as to be compressible. Where a metal foil strip  230  is employed in addition to a deposited conductor  230 , the metal foil strip may simply be compressed against an exposed surface of deposited conductor  230  (i.e. a region not covered by insulator  240 ) by the (insulated) side of an adjacent fiber  200 .  
     [0044] Insulating layer  240  covers both edges of ITO layer  220  on the top  212  of fiber  210  as well as conductor  230  along side  216  of fiber  210 . Insulating layer  240  is patterned on the top surface  212  of fiber  210  to define a plurality of openings in the desired shape of the light-emitting elements  280 . Preferably, because the area of each of the light-emitting elements  280  is desirably as large as possible to maximize the light produced and therefore the brightness of the display in which light-emitting fiber  200  is employed, rectangular elements  280  having opposing edges close to the edges of fiber  210  are desirable. Thus the width of the portion  244  of insulation layer  240  that is disposed along the edges of fiber  210  for defining two edges of openings  242  are typically as narrow as tolerances and processing allow, so long as sufficient width is present to enable the light-emitting material  250  that is later deposited to be fully enclosed or encapsulated. Similarly, the transverse portion  246  of insulation layer  240  defining the space between adjacent openings is made narrow for increasing the area of the openings relative to the area of top surface  212  consistent with tolerances and the width thereof appropriate for insulation between adjacent elements  280  and contact with an upper electrode contact  270  later applied.  
     [0045] Insulation layer  240 , which prevents or reduces moisture and other undesirable material from reaching the OLED light-emitting material  250  while not interfering with the making of electrical connection thereto, furthers achieving long life and high performance of the OLED light-emitting elements  280 . Suitable moisture barrier materials include silicon nitride, silicon dioxide, silicon oxynitride, silicon carbide, diamond-like carbon, and phosphorus-silicate glass, and are typically applied through a mechanical mask.  
     [0046] Alternatively, insulation layer  240  may be formed of an organic layer, such as a layer of a photoresist material. The photoresist may be deposited by dip coating and/or spraying or other suitable method and then be exposed and developed, and then partially removed to form openings exposing ITO electrode layer  220 . The organic layer may also be selectively deposited, such as by screen printing or ink jet printing, in the pattern of layer  240 . Another suitable type of material for insulation layer  240  is an epoxy that is selectively deposited in the desired pattern and is then cured by exposure to ultra-violet light. In each case, however, insulating layer  240  remains in place during the deposition of the OLED stack  250  and the electrode layer  260  and contact layer  270 , and so must be processed to be fully compatible with the OLED and electrode materials and the processing thereof.  
     [0047] It is desirable that conductor  230  wrap around from the side  216  of fiber  210  to the top  212  thereof so as to provide a contact  290  that overlies the portion of ITO layer  220  near end  218  of fiber  210 , or, alternatively, that ITO layer  220  overlap conductor  230 . Electrical bus  230 , which couples a drive signal to the ITO electrodes  220  of each light-emitting element  280  along the length of optical fiber  210 , is preferably covered by insulation layer  240  for providing electrical insulation thereof, particularly when a plurality of fibers  200  are in side-by-side array, as in a display  10 .  
     [0048] Layer  250  of OLED material is deposited on ITO layer  220  and insulation layer  240 . In the simplest form for fabrication, OLED layer  250  may be continuous, or it may preferably be deposited as segments  240  each overlying an opening in insulation layer  240 . OLED layer or stack  250  does not overlie region  290  thereby leaving the end of ITO layer  220  exposed. OLED stack  250  typically includes several different layers of material, each typically having a thickness of about 500 Å, or more or less.  
     [0049] A segmented layer  260  of electron injecting material is deposited on OLED stack  250 , and a relatively durable conductive segmented contact layer  270  is similarly deposited onto segmented electrode layer  260  with the segments of layers  260  and  270  in registration, as illustrated in FIGS. 3A and 3B, although the segments of layer  270  are typically slightly larger than those of layer  260 . The segments of layer  270  extend slightly beyond the edges of OLED layer  250  so as to completely overlie the OLED layer  250  and to contact insulation layer  240  completely surrounding and isolating OLED layer  240 , thereby to retard or prevent moisture and other contaminants from reaching OLED material  250 .  
     [0050] Each stack of hole-injecting layer  220 , light-emitting material  250  and electron-injecting material  260  provides a light-emitting element  280  to which electrical control signals are applied via conductors  220 / 230  and  260 / 270  for causing light-emitting elements  280  to emit light. The electrical control signals applied via conductors  220 / 230  are usually referred to as “select signals” where plural light-emitting fibers  200  are disposed side-by-side in a display, and the electrical control signals applied via conductors  260 / 270  are referred to as “data signals” because their amplitude or duration is controlled to affect the amount of light emitted by light-emitting elements  280 . Where plural fibers  200  are, for example, disposed horizontally in a display, the electrical control signals applied via conductors  220 / 230  are usually referred to as “row selection” signals, and the electrical control signals applied via conductors  260 / 270  are referred to as “column data” signals.  
     [0051] The breaks between adjacent ones of the segments contact layer  270  overlie transverse portions  246  of insulation layer  240  separating adjacent openings therein, so that a substantial part of each transverse portion  246  is covered by contact segment  270  for defining a contact  272  by which electrical connection can preferably be made to the electron-injecting electrode  260  of light-emitting OLED elements  280 . The segments of OLED layer  250  and of electron injecting/contact layers  260 ,  270  are thus of like pitch along the length of optical fiber  210 , but segments of layer  270  are preferably offset so that each segment thereof  270  overlies one transverse portion  246  and provides a contact  272  to electrode  260 .  
     [0052] Top electrode  260  may be a layer of magnesium, magnesium/silver, calcium, calcium/aluminum, lithium fluoride or lithium fluoride/aluminum, or any other stable electron injector. Contact layer  270  may be aluminum, gold, chromium/gold (Cr Au) or copper, for example, or any other durable high-conductivity material. Top electrodes  260  and contacts  270  are in one-to-one correspondence with one another and with a portion of ITO layer  220 , separated by a light-emitting material layer  250 , along the length of optical fiber  210 . It is noted that contacts or connection sites  272 ,  294   a - 294   g  may simply be locations designated such on conductor layer  270  as shown in FIG. 3A or may be sites at which additional thickness of the conductive material of layer  270  or other compatible conductive material is build up for providing a more durable contact, as shown in FIG. 3B.  
     [0053] Contacts  272  are durable and provide a durable contact structure to which conductors providing pixel data signals are connected, which data signal conductors (not shown) lie transverse to the length direction of light-emitting fibers  200  in a display. Because insulating layer  240  lies under the contact  272  portion of contact layer  270 , the connecting of such transversely oriented data signal conductors to such contact  272  cannot cause a short circuit between the hole injecting electrode layer  220  and the electron injecting electrode  250  of any light-emitting element  280 . Even if a portion of OLED layer  250  were to underlie contact  272 , it would not be a portion of OLED layer  250  that produces light and so any damage thereto would not affect operation of any light-emitting element  280 .  
     [0054] Preferably, the deposition of contact layer  270  also produces a contact region  290  and/or contacts  294   a - 294   g  at the end  218  of optical fiber  210  connecting directly to ITO electrode  220  and electrical bus  230  at the end  218  of optical fiber  210  to provide a durable contact structure to which conductors providing row select signals are connected. Also preferably, insulation layer  240 ,  292  defines openings  294 a- 294 n at one or both ends  218  of fiber  210  at which ends of contact layer  290  on ITO layer  220  is exposed for later making electrical connection to the hole-injecting electrode  220  of light-emitting elements  280  and to electrical conductor  230  providing a relatively high conductivity connection thereto. Alternatively, a layer  270  of high-conductivity material may be deposited through openings  294   a - 294   g  in insulation layer  292  to provide a high-conductivity connection to longitudinal conductor  230 .  
     [0055] Thus, suitable electrical connections can be made to couple the select signal and the data signal to respective electrodes  220  and  260  of each light-emitting element  280  for controllably and selectively energizing each light-emitting element  280  to produce the pixels of an image to be displayed by a display including a plurality of light-emitting fibers  200  in parallel side-by-side array. These connections are made to the surface of the light-emitting fibers  200  on which the light-emitting elements are formed, and the light emitted thereby (indicated by arrow  205 ) passes through the optical fiber  210  away from the light-emitting elements  280  to be observed by a viewer of such display. It is noted that because light-emitting fibers  200  may be of any desired length, and because any desired number of such fibers  200  may arrayed side-by-side, a thin panel display of virtually any desired size (height and width) may be assembled utilizing the present invention.  
     [0056] Light emitted by light-emitting element  280  passes through optical fiber  210  to be observed by a viewer of the display including light-emitting fiber  200 , as is indicated by arrow  205 . While the light is generated in OLED material  250 , it passes through the ITO or other thin material of electrode  220  in the direction indicated by arrow  205 . The presence of top electrode  260  and/or contact layer  270  overlying OLED layer  250  desirably reflects light from OLED material  250  and so tends to increase the light output along the direction of arrow  205 .  
     [0057] Fiber  210  is generally of rectangular cross-section having an aspect ratio of thickness to width typically ranging between about 1:1 and 10:1. If fiber  210  is about 0.25 mm (about 0.010 inch) wide, i.e. on the surface having light-emitting elements  280  thereon, it is typically in the range of about 0.25-2.5 mm (about 0.010-0.1 inch) thick, and may typically be about 1.25 mm (about 0.05 inch) thick. If fiber  210  is about 0.38 mm (about 0.015 inch) wide, it is preferably in the range of about 1.5-3.8 mm (about 0.060-0.15 inch) thick, and may typically be about 1.9 mm (about 0.075 inch) thick.  
     [0058] Where light-emitting fiber  200  is utilized in a color display, light-emitting elements  280  emitting three different colors of light, such as red (R), green (G) and blue (B), are utilized. The three different color light-emitting elements are arranged to be in adjacent sets of R-G-B elements, each set providing a color pixel. Such arrangement of R-G-B light-emitting elements may be provided by sequencing R, G and B OLED materials  250  along the length of each light-emitting fiber  200  or may be provided by placing fibers  200  of different colors side-by-side in an R-G-B sequence, i.e. a red-emitting fiber next to a green-emitting fiber next to a blue-emitting fiber and so forth. The red-emitting fibers, green-emitting fibers, and blue-emitting fibers may be fabricated on ribbons or fibers  200  that are each tinted to the desired color or may employ different light-emitting materials that respectively emit the desired color.  
     [0059] In either case, it is preferred that patterned passivating material  240 ,  292  be deposited onto the plurality of fibers  200  in areas not containing contacts  270 ,  272 ,  294 ,  294   a - 294   n , to slow the permeation of moisture and oxygen to the OLED material of the light-emitting elements of fibers  200 , and to reduce the likelihood of short circuits occurring between closely spaced ones of contacts  270 ,  272 ,  294 ,  294   a - 294   n .  
     [0060]FIGS. 4A through 4C are schematic diagrams illustrating the steps in the assembly of an exemplary display module  10  of a light-emitting fiber display including the exemplary electronic circuit  100  of FIG. 1. A flat plate  300  of length exceeding the length of light-emitting fibers  200  and of width exceeding that of the plurality of fibers  200  to be assembled is provided, as shown in FIG. 4A. Flat plate  300  includes, for example, a fixed stop plate  310  that is either attached to or integral with plate  300 . A plurality of light-emitting fibers  200  are placed side-by-side on flat plate  300  adjacent to fixed stop plate  310  with their respective surfaces  202  from which light is emitted against plate  300  and with their respective surfaces having light-emitting elements  280  thereon facing away from plate  300 . Each light-emitting element  280  has an exposed data contact  270 ,  272  at which data signals are to be applied and preferably has a select contact  290 ,  294   a - 294   n  at one or both ends thereof.  
     [0061] A clamp plate  320  is placed against fibers  200  as shown in FIG. 4B to press them against fixed plate  310 . The plurality of fibers are placed on flat plate  300  with their respective ends substantially aligned and, in addition, clamping plates  330  (not shown) may be placed at the respective ends of fibers  200  to maintain the desired alignment. Thus, light-emitting fibers  200  are firmly held in substantially the positions in which they will be disposed in the final assembly of a display module  10  of width W. Alternatively, deposition of the OLED material(s)  250  could be performed after fibers  210  are clamped to plate  300 .  
     [0062] Next, small “dots” or spots  145  of electrically conductive adhesive or of low-temperature solder are deposited on each of the data contacts  270 ,  272 , and small “dots” or spots  146  of the same one of electrically conductive adhesive or of low-temperature solder are deposited on each of the select contacts  294   a - 294   n , also as shown in FIG. 4B. Preferably the dots  145  are on areas thereof that do not overlie the active or light-producing area of the OLED material of the light-emitting elements  280  of fibers  200  and preferably dots  146  are on the contact areas  294   a - 294   n  such as defined by openings in an insulating layer  292 . The select bus contacts  294  may be at one or both ends of fibers  200  and, in such case, conductive dots  146  may be deposited on these select bus contacts  294  at one or both ends of fibers  200  as well.  
     [0063] Next, printed circuit board  100  is placed over the plurality of side-by-side light-emitting fibers  200  with its data bus conductors  140  aligned along corresponding ones of data contacts  270 ,  272  which are disposed transversely across light-emitting fibers  200  and with its select bus conductors  142  aligned with ones of select contacts  294   a - 294   n , as shown in FIG. 4C. Circuit board  100  is moved toward fibers  200  until conductive dots  145 ,  146  are in position to form electrical connections between the respective data bus conductors  140  and select bus conductors  142  of circuit board  100  and the corresponding data contacts  272  and  294   a - 294   n , respectively, of fibers  200 .  
     [0064] Connections  145 ,  146  may be completed by heating, laser heating, passage of time for curing at ambient or elevated temperature, and/or exposure to ultraviolet (UV), as is appropriate to the material utilized for dots  145 ,  146 . For example, where dots  145 ,  146  are of solder, heat is applied to melt the solder dots  145 ,  146  to form permanent solder connections. Where dots  145 ,  146  are of electrically-conductive adhesive, suitable temperature for tacking and/or curing the adhesive is applied.  
     [0065] After conductive adhesive dots  145 ,  146  are cured or the solder dots  145 ,  146  are reflowed to provide the desired electrical connections between circuit board  100  and the plurality of light-emitting fibers  200 , clamp  320  is removed to release circuit board  100  and the plurality of light-emitting fibers  200  attached thereto by conductive dots  145 ,  146  thereby to comprise display module  10 , as shown in FIGS. 2A, 2B and  2 C, which is then removed from flat plate  300 .  
     [0066]FIG. 5 is a schematic diagram of an embodiment of a display or display module  10  employing a compressible spacer  230 ′,  315  in accordance with the invention. Because each of fibers  200  has a width that is subject to tolerance, display  10  also has a width W that is subject to tolerance. Such tolerance may be due to tolerance of the width of fibers  210  and the layers of conductor  230  and insulator  240  thereon as well as other factors including varying intimacy of physical contact between adjacent fibers  200 . Compressible spacer  230 ′ and/or  315  is employed between adjacent ones of fibers  200  to allow the plurality of fibers  200  to be compressed in width to a desired overall width dimension W as indicated in FIG. 4B. As a result, each module  10  is of width W to within a desired tolerance which can be less than the tolerance that could occur if the tolerances of individual fibers  200  were to accumulate, and so the array of fibers  200  will better align with circuit board  100 .  
     [0067] For example, a module  10  including 120 fibers  200  each being about 0.25 mm (about 10 mils or 0.010 inch) wide would be about 30.05 mm (about 1.20 inch) wide. To maintain a width W to within a range of about 30.01-30.06 mm (about 1.185-1.205 inches), the width of each fiber  200  would have to be controlled to within about ±0.5%. Compressible spacer  230 ′,  315  may be an embossed or corrugated material that takes a permanent set when compressed or may be a soft material that squeezes out under compression. Two exemplary spacers  230 ′ and  315  are contemplated, and may be used as alternatives or in combination.  
     [0068] Electrically conductive spacer  230 ′ is an embossed thin metal foil, such as a copper, aluminum or gold foil, for example, of about 12 μm (about 0.5 mil) thickness that is embossed to have about 25 μm (about 1 mil) thickness, that either replaces deposited metal conductor  230  or is contiguous thereto along the length of fiber  200 , i.e. in the space between two adjacent ones of fibers  200 . Alternatively, where deposited conductor  230  is utilized, insulating compressible spacers  315  may be utilized. Insulating spacer  315  is an embossed thin plastic strip, such as Mylar, PVC or other suitable plastic, for example, of like dimension to that described above for spacer  230 ′. Thinner compressible spacers, such as spacers about 6 μm (about ¼ mil) thick, are also desirable.  
     [0069]FIG. 6 is a plan view schematic diagram of an exemplary display  10  in accordance with the invention with the circuit module  100  cut away to leave only conductors  140 ,  142  thereof so as to show connections  145 ,  146 , and FIG. 7 is a plan view schematic diagram of a portion of the display of FIG. 6 enlarged to better show connections  146 . Each of image data conductors  140  connects via ones of conductive dots  145  to a corresponding one of the pixel elements  280  of each light-emitting fiber  200 , thereby making the “column” or “data” connections to the plurality of fibers  200  of display  10 . Because conductors  140  are substantially parallel to each other and transverse to the length of fibers  200 , only the tolerance in the direction along the length of fibers  200  need be of concern in placing and connecting circuit board  100 .  
     [0070] Similarly, each of select conductors  142  connects via one of conductive dots  146  to a corresponding one of the contacts  294   a - 294   g  of a selected one of light-emitting fibers  200 , thereby making the “row” or “select” connections to the plurality of fibers  200  of display  10 . Because select contacts  294 a- 294 g are on the same surface of fibers  200  as are data contacts  270 ,  272 , and because conductors  142  are substantially parallel and transverse to the length of fibers  200 , as are conductors  140 , only the tolerance in the direction along the length of fibers  200  need be of concern in placing and connecting circuit board  100 .  
     [0071] As a result, only the tolerance in one dimension need be controlled in assembly, and not the tolerances in two dimensions as where conductors  140  and  142  are orthogonal, thereby facilitating alignment and assembly of display  10 . Moreover, because the tolerance needed is eased, the tolerances on the width of each fiber  200  and on the width W of a display  10  may also be eased.  
     [0072] As noted above, the contact area  290  at the end  218  of each fiber  200  is preferably coated with a patterned insulator  292  that has one or more openings defining contacts  294   a - 294   n  on each fiber  200  or different contacts on different fibers  200 . Preferably, the contact  294  positions are staggered to increase spacing between proximate ones of connections  146 , e.g., as illustrated in FIG. 7, or may be staggered for the different color R-G-B fibers  200 . For a display  10  having 120 fibers  200  of about 0.25 mm (about 10 mils) width each and having conductors  142  at a pitch of about 0.25 mm (about 10 mils), the connection area at the ends of fibers  200  would be about 30.05 mm (about 1.20 inches), and the placement tolerance for connections  146  may increase from about ±¼ fiber width to about ±2 fiber widths.  
     [0073] Maintaining placement tolerance for connections  145 ,  146  over the length of fibers  200  is not seen to materially change due to the additional length of about 30 mm (about 1.2 inches) at one or both ends of fiber  200 . For a typical HDTV display having an about 168 cm (about 66 inch) screen diagonal and a 16:9 aspect ratio, the length of vertically disposed fibers  200  containing light-emitting elements  280  is about 86 cm (about 34 inches), and so an added length of about 3 cm (about 1.2 inches) at one or both ends of fiber  200  is not material placement tolerances.  
     [0074] Alternatively, and/or additionally, a patterned insulator could be applied over conductors  142  of circuit board  100 , as shown in the alternative arrangement of FIG. 7, to the same end of exposing only the areas of conductors  142  to which connections  146  would connect. A pair of triangular-shaped sheets  160  of insulating material are placed at each end of the side-by-side array of fibers  200 . The triangular insulators  160  are placed hypotenuse-to-hypotenuse but slightly apart to define a diagonal channel  162  so that a set of contacts  294   a , . . . ,  294   n  disposed in diagonal channel  162  are exposed for connection via connections  146  to conductors  142  of circuit board  100 . Insulating sheets  160  are disposed between the array of fibers  200  and conductors  142  of circuit board  100 , and may or may not be attached to one or both of them.  
     [0075] Also alternatively, plural conductors  142  may make plural connections  146  to the select conductor  290  of a particular fiber  200 , as may be convenient for increasing the current-carrying capacity and/or the reliability thereof, such as by providing connection thereto at both ends of each fiber  200 , as shown in FIG. 7. Further, conductors  142  could be segmented so as to either double the number of connections that can be made in a given end-length dimension of fibers  200  or to increase the spacing between adjacent conductors  142 . The foregoing could be utilized to decrease the number of different arrangements for contacts  294   a - 294   n  needed for fibers  200  where each fiber has only one of contacts  294   a - 294   n  exposed through insulator  292 .  
     [0076]FIG. 8 is a plan view schematic diagram of an alternative arrangement of the display  10  of FIG. 7 wherein light-emitting fibers  200 R,  200 G,  200 B producing red, green and blue light, respectively, are offset longitudinally by the spacing of 1 or 2 pixels, respectively. I.e. fibers  200 R,  200 G,  200 B producing light of different colors are disposed in staggered longitudinal relationship. Respective contacts  294   a - 294   n  of fibers  200 R,  200 G,  200 B are likewise staggered and connect to respective conductors  142  of circuit board  100  via connections  146  in like manner to that described above. Triangular insulation sheets  160  may be employed, as above.  
     [0077] One benefit of the arrangement of FIG. 8 is that fewer different patterns of contacts  294  are required in insulation layer  292 , thereby simplifying the processing of fibers  200 R,  200 G,  200 B. As shown, the pattern of contacts  294   a - 294   n  of fibers  200 R,  200 G,  200 B is the same, and additional contact spacing inures from the longitudinal offsetting of the relative positions of fibers  200 R,  200 G,  200 B. This benefit is available for both color and monochrome displays.  
     [0078] For the about 168 cm (about 66 inch) screen diagonal 16:9 aspect ratio HDTV display described above, a longitudinal offset of about 0.75 mm (about 0.030 inch) for each of the  120  fibers  200  would produce an added length of about 9 cm (about 3.6 inches) at one or both ends of fiber  200  as compared to the 86-cm (about 34-inch) length of vertically disposed fibers  200  containing light-emitting elements  280 .  
     [0079] While a light-emitting display may be provided by one display  10  as thus far described, it is desirable to employ a plurality of displays  10  as display modules  10  to provide a larger light-emitting display. FIG. 9 is a rear plan view schematic diagram of an exemplary light-emitting display  20  including a plurality of the display modules  10  of FIGS. 2A through 2C. FIG. 9 is described below in conjunction with FIGS. 10A and 10B which are a side view and an end view schematic diagram, respectively, of the exemplary light-emitting display of FIG. 9, and in conjunction with FIGS. 11A and 11B which are cross-sectional views taken along cross-section lines  11 A- 11 A and  11 B- 11 B, respectively, in FIG. 9.  
     [0080] Display  20  is typically a planar panel comprising a plurality of display modules  10  with the light-emitting surface  202  of light-emitting fibers  200  mounted to a planar faceplate  30 , such as a sheet of glass or transparent plastic, having a surface defining a viewing surface  32  at which a viewer can perceive the information displayed on display  20 . The modules  10  may be mounted by adhesively attaching the fibers  200  of modules  100  to faceplate  30 , such as by an optically transparent adhesive having an index of refraction suitably matched to the indices of refraction of the fibers  200  and faceplate  30 . Alternatively, modules  10  may be mounted with the light-emitting surfaces  202  of fibers  200  spaced away from faceplate  30 .  
     [0081] Adjacent modules  10  may be insulated from each other by a thin insulating spacer or shim (not visible) that prevents contacts or other electrical conductors of the end light-emitting fibers  200  that abut each other to not short circuit. The spacer may be a sheet of Mylar or other plastic, e.g. about ¼ to ½ mil (about 6-13 μm) thick, or may be provided by an insulating layer deposited on at least the ones of fibers  200  that are at the edge on module  10  or by embossed spacers  315  spacing away the edge of the end ones of fibers  200  in each module  10 .  
     [0082] Modules  10  are connected to each other and to other apparatus (not shown), such as an RF tuner, video processor and drive circuits of a television receiver, or to video processing and drive circuits of a video recorder, video disk player, computer or the like, by ribbon cables or other cables having edge connectors that engage edge connections  112 ,  114 ,  116  of circuit boards  100  of modules  10 .  
     [0083] Modules  10  are passivated or sealed to faceplate  30  and to each other to prevent or at least retard the entry of moisture into display  20 . Peripheral seals  40  around the periphery of faceplate  30  and back seals  46  between modules  10  may be a solid fillet of a single- or two-component sealing material, such as epoxy, silicone, or polyimide. Alternatively, peripheral seal  40  may include plural seals such as edge seals  42  and end seals  44  each formed of a glass strip that is sealed to the adjacent faceplate  30  and module  10  by a thin seal of adhesive, epoxy, silicone or polyimide. An advantage of such glass strip seals is that because the glass is impervious to moisture, the sealant or epoxy is much smaller than for a fillet seal and so presents a smaller cross-sectional area through which moisture can permeate.  
     [0084] The sealing may be made by applying the edge seals  42  and back seals  46 , and then applying the end seal  44 , Any one or more of these seals, or all of the seals, may be either a fillet of epoxy or other adhesive or the preferred adhesively-attached glass strip seal, or a combination thereof. Dessicant material may be placed within the volume within display  20  sealed by seals  40 ,  46 , preferably in one or more cavities behind faceplate  30  and along one or more edges thereof, for absorbing any residual moisture that may be sealed within the sealed volume of display  20  or that may penetrate seals  40 ,  46 . The sealed volume of display  20  may also be filled with dry gas, such as dry nitrogen or other inert gas, prior to sealing.  
     [0085] While the present invention has been described in terms of the foregoing exemplary embodiments, variations within the scope and spirit of the present invention as defined by the claims following will be apparent to those skilled in the art. For example, the offsetting pattern of contacts  294   a - 294   g  may have one repetition in any module, as illustrated, or may have two or more repetitions so as to either accommodate a larger number of fibers  200  or provide increased spacing between adjacent connections  146 . In addition, dots of an electrically-insulating adhesive may be placed on fibers  200  in locations not having conductive dots  145 ,  146 , to provide additional strength to the attachment of fibers  200  and circuit board  100 .  
     [0086] Other materials and dimensions and layouts of light emitting elements may be utilized in making the light-emitting fibers, display modules and displays according to the invention, as well as the circuit modules and components thereof, the embodiments illustrated being exemplary.  
     [0087] In addition, circuit boards  100  do not have to include electronic devices  150  as shown, but may include only printed wiring for providing direct conductive connections between edge connectors and the contacts of fibers  200 . In such arrangement, electronic devices for processing and generating display signals, e.g., select signals and data signals, are located remotely from circuit board  100 .