Electric lamp and discharge devices – With luminescent solid or liquid material – Solid-state type
Reexamination Certificate
1999-06-10
2001-07-03
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Solid-state type
C313S505000, C313S500000, C313S509000
Reexamination Certificate
active
06255776
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electronically-controlled displays that can be manufactured as parts of other functional structures. More particularly, the present invention relates to electronic displays, including electroluminescent displays, that can be manufactured as parts of other functional structures.
BACKGROUND OF THE INVENTION
Displays are implemented using a variety of technology areas for use in a wide variety of applications. The technology areas span from the cathode ray tube (CRT), to various field emission display technologies, to light-emitting diode technologies, etc. The uses and applications of displays are without limit. For example, consider some display devices, such as with alphanumeric displays and computer-type display screens, whose primary purpose is to display information, and other display devices that serve secondary functions, such as backlighting user access points or controls. For many of these applications, the size and manufacturability of the display devices are major concerns.
As an example, electroluminescence is one of several popular display technologies that have been used in view of size constraints. Common uses of electroluminescence include, among other uses, backlighting watches and display screens in certain laptop and notebook computers. Electroluminescence technology is conventionally implemented using phosphor material sandwiched between two conductive layers. One of the conductive layers is typically a transparent material, such as mylar, that is coated with a transparent conductor, such as indium tin oxide. When a high voltage of alternating polarity is applied to the respective conductive layers, an electric field is created that excites the phosphor.
Manufacturing devices using displays of this type are cumbersome. In the design of a typical application, at least a three-layer electroluminescent display structure is cooperatively arranged nearby another circuit. This neighboring circuit is arranged to avoid blocking the electroluminescent light, and the electroluminescent display structure is arranged to avoid interfering with the functionality of the neighboring circuit. For many applications, especially those requiring significant generation of light in compact areas, this cooperative arrangement is not practicable.
Accordingly, many applications require displays that can be implemented in small areas while avoiding the disadvantages discussed above.
SUMMARY OF THE INVENTION
One aspect of the present invention is directed to an electroluminescent display device. The display device includes first and second conductive buses adjacent to an electroluminescent medium on a dielectric carrier. The first and second conductive buses have at least one first conductor and at least one second conductor, respectively. These conductors are arranged in close proximity to one another, and they are secured over and supported by the dielectric carrier. The electroluminescent medium is located proximate to the first and second conductors to permit an electric field set up by a voltage applied between the first and second conductors to generate light. In more specific embodiments, the medium is phosphor-based and polymer-based, respectively.
Another aspect of the present invention is directed to a method for manufacturing the above-described electroluminescent display device. According to one embodiment, the method provides the manufacture of a electroluminescent display device on a dielectric carrier. The method includes: applying a first conductive bus having at least one first conductor, and a second conductive bus having at least one second conductor, arranged in close proximity to said at least one first conductor, over the dielectric carrier and forming at least one area therebetween; and depositing a phosphor-based carrier in said at least one area between the first and second conductors, the first and second conductors arranged to excite the phosphors and generate light therefrom.
Another aspect of the present invention is directed to improving the brightness of the device or to improving the method, as described above, by applying a nonconductive material, such as DuPont 7153-type dielectric composition, over the patterned conductive buses, or by using another such material to increase capacitance between the alternately arranged conductors. It has been discovered that such implementation substantially increases the brightness. In a particular application, the brightness has been doubled by using a thin layer of this nonconductive material applied directly over the entire patterned conductive areas. Other materials of this type, e.g., other dielectric compositions, can be used as well.
According to another embodiment of the present invention, an electroluminescent display device is formed on a mirror having a metallized surface. The metallized surface is selectively etched to define a first conductive bus having at least one first conductor and a second conductive bus having at least one second conductor arranged in close proximity to the at least one first conductor. A phosphor-based carrier including phosphor therein is located proximate to the first and second conductors to permit an electric field set up by a voltage applied between the first and second conductors to generate light via the phosphor. The mirror can form part of a liquid crystal device.
Another aspect of the present invention is directed to a method for manufacturing an electroluminescent display device on a mirror having a metallized surface. The metallized surface is selectively etched, defining a first conductive bus having at least one first conductor and a second conductive bus having at least one second conductor in close proximity to the at least one first conductor and forming at least one area between the at least one first conductor and the at least one second conductor. A phosphor-based carrier having a phosphor is deposited in the at least one area. The first and second conductors are arranged to excite the phosphor and generate light therefrom in response to an applied voltage.
The above summary of the present invention is not intended to describe each disclosed embodiment, or every implementation, of the present invention. The figures and the detailed description that follow more particularly exemplify these embodiments.
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Peterson Francis
Walsh David
McDermott & Will & Emery
Patel Ashok
Phillips Plastics Corporation
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