Card – picture – or sign exhibiting – Illuminated sign – Luminescent
Reexamination Certificate
2001-02-13
2004-06-22
Davis, Cassandra H. (Department: 3611)
Card, picture, or sign exhibiting
Illuminated sign
Luminescent
C345S036000
Reexamination Certificate
active
06751898
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains generally to the field of electronic displays. Specifically, the present invention pertains to a compact and light weight electroluminescent display apparatus ideally suited for educational and entertainment presentations and advertising displays.
BACKGROUND OF THE INVENTION
Electroluminescent (EL) devices are commonly used to provide illumination in a variety of products including display panels, board games, watch faces, and keyboards. EL devices typically include a layer of phosphor disposed between two electrodes, at least one of the electrodes being light-transmissive. Because a dielectric is usually disposed between the electrodes, the EL device functions essentially as a capacitor. When a voltage of alternating current is applied across the electrodes, the phosphor material is activated and emits light.
EL devices may be manufactured as discrete cells or as large panels or rolls, and may be formed on rigid or flexible substrates. Each component of the device may be formed as a separate layer, such as a foil sheet serving as an electrode, and a planar dielectric sheet, with the layers being laminated together via a heat and pressure process. Alternatively, the layers may be combined into overlapping coatings printed on a substrate, as is the case for a layer of light-transmissive conductive ink serving as a top electrode followed by a layer of phosphor ink in a dielectric matrix and then another conductive ink coating serving as a back electrode. EL devices have found widespread uses, e.g. in signs, watch faces, and as back lighting for keyboards.
Membrane switches are generally constructed of two spaced-apart electrically conductive surfaces on separate substrates. At least one substrate is flexible. For example, each conductive surface may be a pattern of electrically conductive ink. A spacer layer with an aperture is positioned between the two facing conductive surfaces. When a user depresses the flexible substrate containing one of the conductive surfaces, the two conductive surfaces come into contact thereby causing activation of the switch and closing a circuit. Membrane switches have also been used in a variety of devices, such as on keyboards and control panels for appliances. See, e.g., U.S. Pat. No. 4,683,360 to Maser for a membrane switch combined with an EL lamp panel.
U.S. Pat. No. 4,683,360 to Maser discloses a combined electroluminescent panel activated by a flexible membrane switch. The flexible membrane switch is generally constructed of two spaced-apart electrically conductive surfaces on separate substrates. At least one substrate is flexible. For example, each conductive surface may be a pattern of electrically conductive ink. A spacer layer with an aperture is positioned between the two facing conductive surfaces. When a user depresses the flexible substrate containing one of the conductive surfaces, the two conductive surfaces come into contact, thereby causing activation of the switch and closing a circuit.
U.S. Pat. No. 4,532,395 to Zukowski discloses a combination flexible membrane switch panel disposed adjacent to flexible EL material. The flexible membrane switch includes two spaced-apart electrically conductive surfaces on separate substrates with a spacer layer, having an aperture positioned therebetween. One of the conductive surface is flexible, with another flexible layer, having translucent indicia, positioned adjacent to and spaced apart therefrom. Disposed between the translucent indicia and the flexible membrane is a flexible layer of EL material. In this manner, both the indicia layer and the EL material may be depressed to allow operation of the flexible membrane switch.
Many interactive games and learning devices include flexible membrane switches to allow a user to control some elements of the stimuli these devices produce. In this fashion, the games and learning devices are more likely to hold the attention of a user for a longer period of time when compared to passive devices.
U.S. Pat. No. 5,087,043 to Billings et al. discloses an interactive audio-visual puzzle that includes, in pertinent part, a rigid puzzle form defining a predetermined number of form cutouts, an upper graphic disposed on the form upper surface and a plurality of respective removable puzzle pieces. Each of the puzzle pieces includes a peripheral configuration conforming to that of an associated form cutout and bears a piece graphic. A flexible membrane bears on the underside thereof, along with a plurality of conductors in a predetermined relative disposition. A plurality of respective lower graphics overlie the flexible membrane and underlie the form cutouts. A sound generator produces respective predetermined associated sounds in response to the input signals applied thereto. The flexible membrane conductors, space and ground plane cooperate to form a touch-pad which corresponds to each of the lower graphics electrically connected to the sound generator. In this manner, the sound generator is selectively actuated to produce sounds in response to input signals. A drawback with Billings et al. is that no animation is provided which would provide the puzzle with more appeal to a user.
U.S. Pat. No. 4,703,573 to Montgomery et al. discloses a visual audible activated work that includes, in pertinent part, at least two pages pivotally attached to each other so that the pages are pivotal from a juxtaposed closed position to an adjacent opened position. A liquid crystal display (LCD) is affixed to one of the pages. A sound generator is attached to the LCD, and a power supply is coupled to automatically provide power to both the sound generator and the LCD when the pages are paced in the opened position. A drawback with Montgomery et al. is that the LCD display limits the number and variety of interactive devices that may be present on any given page.
A variety of billboard and signboard systems are available for indoor and outdoor advertising. U.S. Pat. No. 5,123,192 to Hsieh discloses a display system that includes a liquid crystal display plate. The display plate is typically positioned indoors between a product to be advertised and a store-front window. The display pate is visible from the outside, and is adapted to alternatingly become transparent and translucent. In this fashion, the display plate periodically forms images which may associated with the product and allows viewing of the product through the windows, without any images being present.
U.S. Pat. No. 4,739,567 to Cardin discloses a display system for a store-front window that includes a retractable projection screen, a slide projector and a mirror. The projection screen is disposed proximate to the window, with the mirror disposed opposite to the window. The slide projector is positioned to direct an image away from the window onto the mirror. The mirror is orientated to project the optical image information onto the screen. A timer is employed to allow the screen to be periodically retracted. Typically, the timer means retracts the screen during the daylight hours so that the store-front window may be used as a simple display window. During the evening hours, the projector screen is lowered so that images may be viewed thereon. A second timer means is employed to sequence the slide projector through the queue of slides contained therein. A drawback with the two aforementioned systems is that they are relatively complicated, requiring precise orientation of the various components of the system, thereby precluding portability.
Many portable viewing screens are available in the prior art. U.S. Pat. No. 4,169,658 to Brown and U.S. Pat. No. 4,110,003 to Zinn each discloses a portable projection screen that includes a flexible viewing surface. The flexible viewing surface is typically stored in a portable housing and may be extended therefrom to facilitate viewing optical information generated from, for example, movie or slide projectors. A drawback with these devices is that the operation of the screens depends upon the availability of a projection
Heropoulos George W.
Torma Tamas L.
Burns Doane , Swecker, Mathis LLP
Davis Cassandra H.
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