Abstract:
An improved system for backlighting a visual effect of interest is presented. The system includes a lenticular luminescent lens, an electroluminescent (EL) light source and a power source coupled to the EL light source. The lenticular luminescent lens includes a luminescent substance disposed thereon/therein for providing the visual effect of interest when exposed to stimulating light. The EL light source is affixed to a surface of the lenticular luminescent lens. When the power source applies power to the EL light source, the EL light source activates an area of illumination backlighting the visual effect of interest.

Description:
CROSS-REFERENCE TO RELATED CASES  
       [0001]     This patent application is claims priority to commonly owned U.S. Provisional Patent Application Ser. No. 60/482,168 (Attorney&#39;s Docket No.102445-100) entitled “LENTICULAR MEDIUM WITH ELECTRO-LUMINESCENT BACKLIGHTING” that was filed on Jun. 24, 2003. The disclosure of U.S. Patent Application Ser. No. 60/482,168 (Attorney&#39;s Docket No. 102445-100) is incorporated by reference in its entirety herein. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to lighting systems for advertising and entertainment media and, more particularly, to backlighting lenticular medium employed in such media with an electro-luminescent device.  
         [0004]     2. Description of Prior Art  
         [0005]     It is well known to use a lenticular luminescent material as a display element in display systems. Generally speaking, the lenticular luminescent material includes a substrate containing a luminescent substance that is capable of fluorescence in response to stimulating light such as, for example, ultraviolet radiation, visible light, near-infrared radiation and the like. One such lenticular luminescent display element is described in U.S. Pat. No. 5,021,931, issued Jun. 4, 1991, to Fumio Matsui et al., the disclosure of which is incorporated by reference herein in its entirety.  
         [0006]     Lenticular luminescent materials may be used to provide animated and three-dimensional (3-D) graphics in the advertising and entertainment industries and is commonly employed, for example, in signage, postcards, compact disc mailer covers, pop ups, stickers, cups, key chains, sew-on appliqués, buttons and trading cards.  
         [0007]     One perceived disadvantage of conventional lenticular luminescent material is that as luminescent light is emitted from the material it is scattered in every direction. Therefore, the efficiency with which an applied stimulating light is utilized is low as is the intensity of luminescent light emitted from the material. As a result, the graphics provided by the lenticular luminescent material is relatively dark when viewed by an observer.  
         [0008]     The present invention provides a solution to this deficiency by utilization of electroluminescent (EL) lamp.  
         [0009]     Conventional EL lamp manufacturing techniques may be divided into two basic processes. The first, a screen-printing process in which a lamp is constructed layer by layer. More particularly, the lamp is constructed using the steps of making indium tin oxide (ITO) plated plastic film; applying EL phosphor ink on the ITO plating to form lighted areas; applying capacitive dielectric ink over the EL phosphor ink; applying electrically conductive ink over the capacitive dielectric ink to form a second capacitive plate; applying electrically conductive ink over the ITO plated plastic film outboard of the capacitive dielectric ink layer to provide a front capacitive electrode connection. This first construction is typically protected from environmental attack by means of either an encapsulating lamination, or secondarily by application of a water repellant electrical insulating coating containing an ultraviolet light activated polymer. An example of this method of manufacturing is described in U.S. Patent Application Publication No. 2003/0003837, which is incorporated by reference herein in its entirety.  
         [0010]     The screen-printing process allows intricate graphics effects to be created using relatively simple manufacturing processes. However, screen-printed EL lamps having high luminance or superior electrical characteristics tend to be costly to manufacture. This is due in part to the difficulty of precisely aligning all conductive, insulating and light emissive layers when processing is performed with typical screen-printing methods. Such layer-to-layer alignment difficulties can result in decreased production yields, especially in applications where there is limited space to provide electrical clearance between the rear electrode and front electrode connection described above.  
         [0011]     The second common process is a laminated EL lamp assembly. In this process, a first film, which supports a metal foil, is passed below a metering roller or blade that applies an insulating layer of capacitive dielectric ink. A second, light transmissive ITO plated film is similarly passed below a roller or blade, which applies a layer of EL phosphor ink onto the ITO plating. In order to achieve both a uniform light output and reliable electrical characteristics, the thickness of the insulating dielectric and phosphor layers must be precisely controlled, along with the grain dispersion of the EL phosphor particles within the phosphor layer. This typically continuous lamination requires tight control over both ink rheology and ink application processes. An improved example of this manufacturing method is described in U.S. Pat. No. 5,667,417, which is incorporated herein by reference in its entirety.  
         [0012]     Once the ink layers have dried and been inspected for defective areas, the first and second films are laminated together to form an EL lamp core. This film lamination method requires heat and/or pressure, which must be tightly controlled so that the light and electrical characteristics of the finished lamp are consistent. Additionally, since the EL phosphor layer is sensitive to water contamination, once the finished lamp is cut into usable shape and size and electrically terminated, it is then encapsulated within a moisture resistant lamination film.  
         [0013]     The continuous lamination method produces foil EL lamps, which are high performance, high priced lamps typically unsuitable for complex graphics or other price sensitive applications. Laminated foil EL lamps are also typically thicker and less flexible than screen printed lamps, limiting their application to those where flexibility and thickness are of less concern.  
         [0014]     In both of the above methods, metal and metal oxides are plated upon a plastic carrier film that is typically used as the basis material for the front conductive layer. The usual film of choice is polyester plastic film plated with ITO. This particular plating exhibits the additional construction weakness of fracturing under close bend radius flexing. These fractures have been demonstrated to cause both dimmed areas, and even total non-illumination of EL lamps of these constructions, due to the interrupted current path at the location of breakage.  
         [0015]     In copending U.S. patent application Publication No. 2003/0003837, a low cost method for manufacturing water resistant EL lamps for consumer applications is described. The inventors have realized that an EL lamp manufactured in accordance with this copending application may be used to backlight lenticular luminescent material and to solve the aforementioned disadvantage (e.g., relatively dark displays) of using such materials in, for example, products for the advertising and entertainment industries.  
         [0016]     The inventors have also realized that an EL lamp manufactured using a screen printable ITO paste or powder directly on substrates such as, for example, treated (e.g., heat treated) or untreated polyester, fabrics, plastics, leather, cloth and polycarbonates as the rear or front electrode may be used to manufacture electroluminescence to solve the aforementioned disadvantage. In another embodiment, the ITO paste or powder may be applied directly onto the Lenticular medium.  
       SUMMARY OF THE INVENTION  
       [0017]     The above and other objects are achieved by an improved system for backlighting a visual effect of interest. One aspect of the present invention is drawn to a system for backlighting a visual effect of interest, comprising: 
        a lenticular luminescent lens having a luminescent substance disposed thereon and/or therein for providing said visual effect of interest when exposed to stimulating light;     an electroluminescent (EL) light source affixed to a surface of said lenticular luminescent lens for providing an area of illumination about said visual effect of interest; and     a power source coupled to said EL light source;     wherein when said power source applies power to said EL light source, said EL light source activates said area of illumination backlighting said visual effect of interest.       
 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     The features and advantages of the present invention will be better understood when the Detailed Description of the Preferred Embodiments given below is considered in conjunction with the figures provided, wherein:  
         [0023]      FIG. 1  is an exploded, isometric view of a backlit lenticular assembly constructed in accordance with one embodiment of the present invention;  
         [0024]      FIG. 2A  is a cross sectional, side view of one embodiment of the backlit lenticular assembly of  FIG. 1 ;  
         [0025]      FIG. 2B  is a cross sectional, side view of another embodiment of the backlit lenticular assembly of  FIG. 1 ; and  
         [0026]      FIG. 3  is a top, plan view of the backlit lenticular assembly of  FIG. 1 . 
     
    
       [0027]     Like reference numbers and designations in the various drawings indicate like elements.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]      FIG. 1  is an exploded, isometric view of a backlit lenticular assembly  10  formed, in accordance with one embodiment of the present invention, as a layered construction including a lenticular luminescent lens  20 , an optical adhesive  30  and an EL light source  40 . In one embodiment, the assembly  10  includes a laminate top coating or layer  80  providing protection from environmental and/or other hazards.  
         [0029]      FIGS. 2A and 2B  are cross-sectional, side views of the backlit lenticular luminescent assembly  10  of  FIG. 1 . As shown in  FIGS. 2A and 2B , the optical adhesive layer  30  affixes the lenticular luminescent lens  20  to a surface of the EL light source  40 .  
         [0030]     The lenticular luminescent lens  20  includes a material such as, for example, a transparent synthetic resin material  22  having a luminescent substance  24  such as, for example, benzoyltrifluoroacetone or the like, mixed therein ( FIG. 2A ) and/or applied thereto ( FIG. 2B ). In one embodiment, the luminescent substance  24  may also include polycarbonate, polyvinyl chloride or polyesters or more than one of these. The resin material  22  is transparent to facilitate backlighting as is described below.  
         [0031]     In accordance with one aspect of the present invention, the luminescent substance  24  is either mixed within or applied to the surface of synthetic resin material  22  or both such that a visual effect of interest is apparent to an observer when the substance  24  is exposed to stimulating light. In one embodiment, the visual effect is one of the aforementioned graphics for use in the advertising or entertainment industries. In another embodiment, the visual effect is a 3-D effect that varies in relation to a position of an observer.  
         [0032]     In one embodiment, the EL light source  40  is an EL lamp having a low electric current consumption, good mechanical durability and sufficient flexibility to bent and conform to curved surfaces. Preferably, the EL light source  40  emits light evenly over a wide area rather than from a point source. This permits production of unique construction for improving both daytime and nighttime visibility as described herein.  
         [0033]     In one embodiment, the EL light source  40  is an EL lamp constructed in accordance with the method of manufacture described in the aforementioned, copending U.S. patent application Publication No. 2003/003837. In this embodiment, illustrated in  FIGS. 2A and 2B , the EL light source  40  includes a plastic film or paper core stock  42 , a capacitive electrode layer  44 , a front capacitive electrode power distribution bus  46 , a capacitive dielectric insulation layer  48 , an EL phosphor layer  50 , and a light transmissive electrically conductive layer  52 .  
         [0034]     As shown in  FIGS. 2A and 2B , various layers of EL light source  40  encapsulate lower layers. For example, the capacitive dielectric insulation layer  48  is allowed to fill a gap between the rear capacitive electrode  44  and the front capacitive electrode power distribution bus  46 . Also, while EL phosphor layer  50  is allowed to bleed beyond edges of the rear capacitive electrode  44 , it does not contact the front capacitive electrode power distribution bus  46 , and in conjunction with the dielectric insulation layer  48 , provides electrical isolation between layers the capacitive electrode  44  and the light transmissive electrically conductive layer  52 . Additionally, the light transmissive electrically conductive layer  52  contacts the front capacitive electrode power distribution bus  46  making electrical connection between the conductive layer  52  and the power distribution bus  46 .  
         [0035]     In one embodiment, the EL light source  40  also includes a light transmissive polyester film environmental encapsulation (not shown). The light transmissive polyester film environmental encapsulation bleeds beyond all lower layers and extends onto the core stock  42 , providing both an electrical safety isolation and an environmental attack resistant encapsulating envelope.  
         [0036]     In yet another embodiment, the EL light source  40  is comprised of an ITO paste or powder applied directly (e.g., by silk screening or by disposition) to a surface of the lenticular luminescent lens  20 . For example, in one embodiment wherein the lens  20  is comprised of a treated (e.g., heat treated) or untreated polyester, fabric, plastic, leather, cloth or polycarbonate, an ITO paste or powder is applied to a surface of the lens  20 . The inventors have discovered that the use of ITO paste or powder as an EL lamp provides improved illumination of the visual effects of interest. For example, the ITO paste or powder is more flexible and can permits application of the EL light source  40  to the surface of the lenticular lens  20  via an iron on decal appliqué. One supplier of suitable ITO paste or powder is Read Advanced Materials of Providence, R.I., USA. In one embodiment, the composition of the lens  20  is ninety percent (90%) ITO powder and ten percent (10%) zinc mixed into a resin binder.  
         [0037]     In one embodiment, the ITO paste or powder is applied to the lenticular lens by using a screen printing process that is similar to a roll to roll manufacturing process using digital optics, and xyz and theta registration, as described in the aforementioned, copending U.S. patent application Publication No. 2003/003837.  
         [0038]     As shown in  FIGS. 1, 2A  and  2 B, the EL light source  40  is affixed to a surface of the lenticular luminescent lens  20 , e.g., a bottom surface  26  of the lens  20 , to backlight the visual effect of interest. It should be appreciated that the EL light source  40  may illuminate an entire surface of the lenticular luminescent lens  20  or a portion thereof, as desired by a particular implementation or embodiment of the present invention.  
         [0039]      FIG. 3  illustrates a top, plan view of the backlit lenticular luminescent assembly  10 . As shown in  FIG. 3 , the rear capacitive electrode  44  and the EL phosphor layer  50  define a rectangular area of illumination. It should be appreciated, however, that the specific shape of the area of illumination is not limited to a rectangular configuration. As such, it is within the scope of the present invention for the area of illumination to include other geometric shapes such as, for example, circles, squares, triangles and portions thereof.  
         [0040]     As illustrated in  FIG. 3 , the lenticular luminescent assembly  10  includes conductors  60  and  62 , such as metal foil conductors. The conductors  60  and  62  couple the rear capacitive electrode  44  and front conductive layer  52  to an electrical power source  70  such as, for example, a battery or electrical outlet. When suitable alternating current (AC) or pulsed direct current (DC) power is applied to the conductors  60  and  62 , current flows between the capacitive plates (e.g., electrode  44  and conductive layer  52 ) energizing the EL phosphor layer  50  illuminating the EL light source  40  and backlighting the lenticular luminescent lens  20  and the visual effect of interest.  
         [0041]     While not shown or described herein, it should be appreciated that it is within the scope of the present invention for the lenticular luminescent assembly  10  to be coupled to the electrical power source  70  via an inverter to convert between AC and DC power. Additionally, the assembly  10  may be coupled to the power source  70  through switches and/or timing circuitry to permit selective or timed illumination of the EL light source  40 , the lenticular lens  20  and the visual effect of interest.  
         [0042]     While the inventive backlighting assembly  10  has been described and illustrated in connection with preferred embodiments, many variations and modifications, as will be evident to those skilled in this art, may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited to the precise details of methodology or construction set forth above as such variations and modification are intended to be included within the scope of the invention.