Abstract:
Electroluminescent (EL) display systems and methods for illuminating an EL display system. One such EL display system includes an electroluminescent (EL) signage having an associated image, a printed conductor pattern, and a plurality of electrical contacts pads associated with the conductor pattern. A frame having a plurality of electrical contacts for operable connection with the contacts of the EL signage is provide. The frame is adapted to at least partially receive the EL signage and cause the EL signage to be in electrical communication with a power source and a microcontroller for activating the EL signage in a predetermined pattern.

Description:
FIELD OF THE DISCLOSURE  
       [0001]     The disclosure is directed to an electroluminescent (EL) display systems and, in particular, to systems for assembling and using EL signage.  
       BACKGROUND AND SUMMARY  
       [0002]     Signage, such as a sign, display, billboard, symbol or a poster, can be used to attract the attention of consumers. Signage can be illuminated or non-illuminated. Illumination of signage is often provided by incandescent or fluorescent lighting systems which are expensive to construct and operate.  
         [0003]     In order to provide lower cost illumination of signs, displays, billboards, and the like, newer, lower cost illumination devices may be used. For example, one type of signage in use today uses electroluminescence (EL) technology to create a display in which parts of the image emit light. Illumination of the signage is provided by placing alternating electric fields across a layer of electroluminescent material that is sandwiched between a transparent conductor layer and a second conductor layer usually with an intervening dielectric to prevent voltage breakdown.  
         [0004]     A translucent substrate having an image printable layer may be applied to an electroluminescent substrate containing the electroluminescent material and an image may be printed on the image printable layer. Upon activation of the electroluminescent material, the image is illuminated. Construction of one such electroluminescent signage is described for example in U.S. Publication No. 2002/0090495, the disclosure of which is incorporated herein by reference.  
         [0005]     Conventional EL display systems are typically highly customized. Hence, everything from the signage to the driving electronics is unique to a particular end use of the signage. Thus, the user&#39;s ability to implement changes to the signage is limited and changes or alterations of the signage may be extremely costly.  
         [0006]     Another disadvantage of conventional electroluminescent display systems is that illumination of the entire electroluminescent signage at one time is usually required. Accordingly, it is difficult to provide selective illumination or the appearance of motion. Accordingly, there remains a need for improved electroluminescent display systems.  
         [0007]     With regard to the foregoing needs, exemplary embodiments of the disclosure provide, for example, electroluminescent (EL) display systems and methods for illuminating an EL display system. One such EL display system includes an electroluminescent (EL) signage having an associated image, a printed conductor pattern, and a plurality of electrical contacts associated with the conductor pattern. A frame having a plurality of electrical contacts for operable connection with the contacts of the EL signage is provide. The frame is adapted to at least partially receive the EL signage and cause the EL signage to be in electrical communication with a power source and a microcontroller for activating the EL signage in a predetermined pattern.  
         [0008]     Another exemplary embodiment of the disclosure provides a method for illuminating an image printed adjacent an electroluminescent (EL) substrate. The substrate has a conductive pattern and a plurality of electrical contacts associated therewith. The EL substrate is physically associated with a frame having a plurality of electrical contacts for operable connection with the contacts of the EL substrate. A microcontroller and power source are provided for activating the conductive pattern of the EL substrate. The conductive pattern is activated to cause illumination of the EL substrate in a predetermined pattern.  
         [0009]     An advantage of at least some of the foregoing embodiments is that customized signage using EL materials may be made at or proximate to a customer&#39;s site using relatively inexpensive imaging apparatus, such as printers. The resulting EL signage may be, for example, interchangeably inserted into a frame for selectively illuminating portions of the EL material in the signage. Hence, signage may be provided that enables a wider range of design features and improved interchangeability. The systems described herein might also enable power to be applied to selective conductors with respect to time to give the appearance of motion. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     Further advantages of the exemplary embodiments may become apparent by reference to the detailed description when considered in conjunction with the elements through the several views, and wherein:  
         [0011]      FIG. 1  is a cross-sectional view, not to scale, of an electroluminescent (EL) signage for an EL system according to the disclosure;  
         [0012]      FIG. 2  is plan view, not to scale, of an EL signage system according to the disclosure;  
         [0013]      FIG. 3  is a perspective view, not to scale, of an EL signage frame according to an alternate embodiment of the disclosure; and  
         [0014]      FIG. 4  is a schematic diagram of a control system for an EL signage system according to the disclosure. 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0015]     As described in more detail below, one embodiment of the disclosure provides a system and method for providing improved EL signage and display systems. A pattern(s) may be printed on an EL substrate to provide, for example, a customized sign or display that is receivable into a separate frame (which might also be referred to, in some embodiments, as a sign or display holder). The pattern(s) may correspond to encoded information that enables a controller in the display holder to selectively illuminate portions of the sign. Since the system enables interchangeability of signs with the holder, a number of different signs may be used with a single sign holder enabling a user to quickly change the sign and its display options.  
         [0016]     With reference to  FIG. 1 , there is provided a cross-sectional view of an EL signage  10  including an image pattern  12  printed adjacent (e.g., on) a first surface  14  thereof and a conductor pattern  16  printed adjacent (e.g., on) a second surface  18  thereof. The substrate  20  is an EL substrate. Current commercially available EL substrates  20  typically include an insulative or dielectric layer  22 , an EL material layer  24 , a translucent conductor layer  26 , and a translucent protective layer  28 . An image receiving layer  30  may be applied to the translucent protective layer  28  to provide a suitable surface for receiving the image pattern  12 .  
         [0017]     In an exemplary embodiment, the image pattern  12  may be provided by an imaging substance, such as monochrome or color inks. Such a substance may be applied to the image receiving layer  30  using, for example, screen printing, rotogravure printing, flexographic printing, lithographic printing, laser printing, ink jet printing, and the like. More flexibility in applying an image to the image receiving layer  30  may be provided by ink jet printing as described in U.S. Publication No. 2002/0090495.  
         [0018]     The conductor pattern  16  applied to the dielectric layer  22  may likewise be applied by a wide variety of printing techniques including, but not limited to, vacuum deposition, chemical vapor deposition, electroplating, screen printing, rotogravure printing, flexographic printing, lithographic printing, and ink jet printing. The conductive pattern  16  may be a single conductive layer or, as shown in  FIG. 1 , may be a particular conductor pattern on the dielectric layer  22 . Conductive inks that may be used to provide the conductor pattern  16  by a printing method, include, but are not limited to inks containing copper, silver, or carbon particles. In order to provide increased flexibility for design and operation of the EL signage, a conductive ink may be applied by a micro-fluid ejection device. The thickness of the conductor pattern  16  may range from about 0.5 to about 5.0 microns. As described in more detail below, electrical contacts (e.g., contact pads) are provided in electrical communication with the conductor pattern  16  for connection to a frame, such as a sign holder.  
         [0019]     The insulative or dielectric layer  22  typically has a thickness ranging from about 20 to about 200 microns and may be provided by a material having a dielectric constant at 20° C. of greater than about fifty. Suitable materials having relatively high dielectric constants include, but are not limited to, barium or strontium titanate dispersed in a polymeric material, and titanium dioxide dispersed in a polymeric material. A particularly suitable polymeric material for dispersing the barium, strontium, or titanium compounds is a fluoropolymer material such as poly(tetrafluoroethylene). Accordingly, a particularly suitable dielectric layer  22  includes barium titanate dispersed in a fluoropolymer layer.  
         [0020]     The EL layer  24  may include organic and/or inorganic EL materials. Inorganic materials typically provide brighter luminous characteristics and may be selected from terbium-doped zinc sulfide (ZnS:Tb), manganese-doped zinc sulfide (ZnS:Mn), cerium-doped yttrium aluminum garnet (YAG:Ce), copper-doped zinc selenium sulfide (ZnSeS:Cu), europium-doped strontium barium silicon oxide (SrBaSiO4:Eu), cerium-doped strontium sulfide (SrS:Ce), copper-doped strontium sulfide (SrS:Cu), copper and silver-doped strontium sulfide (SrS:Cu,Ag), and the like. The thickness of the EL layer  24  may range from about 100 nanometers to about 5 microns.  
         [0021]     The conductor layer  26  of the EL substrate  20  is typically made of a translucent conductive material such as indium tin oxide (ITO) and has a thickness ranging from about 50 to about 10,000 Angstroms. A protective transparent or translucent protective layer  28  is applied to the translucent conductor layer  26 . The layer  28  may be selected from polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and the like. The thickness of the protective layer  28  may range from about 20 to about 150 microns. The EL substrate  20  is relatively thin and ideally flexible so that it can be easily handled in an imaging apparatus, such as an ink jet printer. Overall, the thickness of the EL substrate  20  ranges from about 0.1 to about 0.5 millimeters. EL substrates  20  as described above are commercially available from BKL, Inc. of King of Prussia, Pa., Luminescent Systems, Inc. of Lebanon, N.H., and Edmund Optics, Inc. of Barrington, N.J.  
         [0022]     An image receiving layer  30 , such as an ink receptive layer, can be applied adjacent (e.g., to) the protective layer  28  of the EL substrate  20 . An ink receptive layer, for example, may be provided by a wide variety of micro-porous organic or inorganic materials that are compatible with the ink applied to form the image pattern  12 . One such ink receptive layer is a layer of fumed silica in a binder. The thickness of the ink receptive layer may range from about 20 to about 150 microns.  
         [0023]     The ink receptive layer may be applied to the protective layer  28  by a wide variety of coating techniques, include but not limited to, roll coating, doctor blade coating, spray coating, dipping, screen coating, and the like. However, in order to minimize the cost of the EL signage  10 , the ink receptive layer may be applied by a micro-fluid ejection device in the same pattern as the image pattern  12 , since the image pattern is not applied to the entire area of the EL substrate  20 .  
         [0024]     As illustrated in  FIG. 2 , another element of the EL display system is a frame  40 , such as one for removably receiving the EL signage  10  described above. The frame  40  may be adapted for slidably receiving the EL signage  10  therein as shown in  FIG. 2 . In one alternative, as shown in  FIG. 3 , a frame  42  may containing an upper frame section  44  and lower frame section  46  that may be removably attached to one another with the EL signage  10  placed between the upper and lower frame sections  44  and  46 . In another alternative, the upper and lower frame sections may be hingedly attached to one another.  
         [0025]     The frame  40  or  42  may have electrical contacts  48  disposed on one end  50  or  52  thereof for electrical contact communication with contact pads  54  on the EL signage  10 . The electrical contacts  48  are desirably spring loaded contacts that make a positive electrical connection with the contact pads  54 .  
         [0026]     As shown in  FIGS. 2 and 3 , the contact pads  54  are disposed on a leading edge  56  of the EL signage  10 . However, it will be appreciated that the contact pads  54  may be disposed along two or more edges of the EL signage  10  or, such as in the case of frame  42 , may be located at any intermediate location on the EL signage  10  between the edges. However, locating the contact pads  54  along the leading edge  56  of the EL signage  10  enables increased flexibility with regard to construction of alternate EL signs  10  for use with frames  40  or  42 . As with the conductor layer  16 , the contact pads  54  may be printed onto the EL signage  10  in a location for electrical communication with the electrical contacts  48  on the frame  40  or  42 .  
         [0027]     The frame  40  or  42 , may be removably attached to a base  60  ( FIG. 2 ) having a power source  62 , a microcontroller  64 , and EL driver circuits  66 . Selective illumination of the EL signage  10  may be obtained by the detection or absence of certain of the contact pads  54  on the EL signage  10 . Low cost microcontrollers  64  may be used to detect the contact pads  54  providing an EL signage pattern and to provide the needed sequencing and timings required to implement the desired display features. For example, the microcontroller  64  can interface with the EL driver circuits  66  to activate selective portions of the EL layer  24  to cause illumination thereof. Conventional integrated circuits (IC&#39;s) may be used to provide the EL driver circuits  66 . In the alternative, the microcontroller  64  and the EL driver circuits  66  may be combined into a single customized integrated circuit to provide a further cost improvement for the EL signage  10 .  
         [0028]     A schematic illustration of an encoded pattern used to provide input to the microcontroller  64  is illustrated in  FIG. 4 . According to  FIG. 4 , the EL signage  10  has a single image  70  thereon that is illuminated by activation of contact pads  54   a  and  54   b  by EL driver circuits  66  through electrical contacts  48   a  and  48   b . Selective activation of contact pads  54   a  and  54   b  is provided by encoded information obtained by electrical contacts  48   c  and  48   d . In the case of contacts  48   c , contact pad  54   c  provides a logic low signal to the microcontroller  64  because there is current flowing through the electrical contacts  48   c  to ground. Conversely, contacts  48   d  provide a logic high signal to the microcontroller  64  because of the absence of a contact pad as shown.  
         [0029]     The foregoing illustration provides an EL display system  80  with a single image. However, the concept may be expanded to provide an EL display system with multiple images. For example, there may be provided an EL signage  10  having up to 3 separate images associated with three separate EL substrates. Each of the images may be displayed in any order and each may either blink on or be on continuously. Also, for each image, the delay time between steps in an illumination sequence may be either “normal” or “long”.  
         [0030]     In the foregoing example, there are ten contact pad locations wherein the contact pad  48  may be present or absent as shown in  FIG. 4 . Four of the ten contact pad locations may be used to encode fifteen sequencing possibilities as follows:  
         [0031]     1) Image 1 only  
         [0032]     2) Image 2 only  
         [0033]     3) Image 3 only  
         [0034]     4) Image 1 then Image 2  
         [0035]     5) Image 2 then Image 1  
         [0036]     6) Image 1 then Image 3  
         [0037]     7) Image 3 then Image 1  
         [0038]     8) Image 2 then Image 3  
         [0039]     9) Image 3 then Image 2  
         [0040]     10) Image 1 then Image 2 then Image 3  
         [0041]     11) Image 1 then Image 3 then Image 2  
         [0042]     12) Image 2 then Image 1 then Image 3  
         [0043]     13) Image 2 then Image 3 then Image 1  
         [0044]     14) Image 3 then Image 1 then Image 2  
         [0045]     15) Image 3 then Image 2 then Image 1  
         [0046]     For each image, two contact pad locations may be used to set (1) blink/on steady and (2) normal/long step delay. Hence, two contact pad locations are used for each of the three images providing a total of ten contact pad locations for the three images and the sequences described above.  
         [0047]     It will be appreciated that since the contact pads  48  are disposed on the EL signage  10 , different signage may be provided with different images and encoded sequences while still using the same frame  40  and base  60 . Hence the system  80  may provide a user with enhanced flexibility with respect to EL signage.  
         [0048]     It is contemplated, and will be apparent to those skilled in the art from the preceding description and the accompanying drawings, that modifications and changes may be made in the embodiments of the disclosure. Accordingly, it is expressly intended that the foregoing description and the accompanying drawings are illustrative of preferred embodiments only, not limiting thereto, and that the true spirit and scope of the present disclosure be determined by reference to the appended claims.