Optical waveguides – Miscellaneous
Reexamination Certificate
2000-08-02
2002-12-03
Sanghavi, Hemang (Department: 2874)
Optical waveguides
Miscellaneous
C385S901000, C385S049000, C385S089000, C385S116000, C362S554000, C362S555000, C345S046000
Reexamination Certificate
active
06490402
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to electronic, light-emitting displays.
BACKGROUND OF THE INVENTION
Electronic displays present various forms of display information, such as text, graphics, and video, as a pixelized image to a user. The presentation of pixelized display information may be an essential function of an electronic device, such as personal computer. In other applications, pixelized display information enhances the features of an electronic device, such as enabling a cellular telephone to be readily programmable and to provide functions such as digital paging.
A number of electronic display technologies are available, each having specific attributes that limit their application. Cathode Ray Tubes (CRTs), for instance, are widely used for computer monitors and televisions. CRTs have good color, contrast, and brightness, as well as being a mature, economical technology. CRTs are not particularly compact, being limited by the geometries imposed by its electron gun and pixel elements formed at substantially perpendicular relation to the electron gun. Moreover, the vacuum requirements of a CRT dictate a heavy glass construction. Thus, the size, weight, rigid fragile construction, and power consumption of CRTs limits their use in portable applications.
As an alternative to CRTs, plasma screen technology allows for a display flatter and wider than CRTs and rear projection televisions. However, plasma screen technology is difficult to manufacture, and thus expensive. Moreover, although flatter than CRTs, plasma screens have similar limitations as do CRTs for weight and rigidity. Consequently, plasma screen displays are used in certain notebook computers and relatively expensive portable devices.
Various other technologies allow for flat, lighter weight, and lower power consumption than CRTs, appropriate to more portable applications. Liquid Crystal Displays (LCD) and active matrix LCDs are widely used in notebook computers and personal digital assistant (PDA) products, for example. To provide a degree of flexibility and resistance to impact, plastic LCDs are known. Also, LCDs are generally less expensive than other displays of comparable size; however, LCDs are generally too expensive to incorporate into limited life, disposable products.
Consequently, a significant need exists for a light weight, inexpensive display, especially a color display that is suitable for use in portable electronic devices and a variety of applications.
SUMMARY OF THE INVENTION
The present invention generally provides a light-emitting fabric that provides for a flexible display suitable for use as a substitute for known portable electronic displays, as well as enabling new applications unsuited to known display technology.
In one aspect consistent with the invention, a light-emitting diode (LED) matrix is formed from interlaced weft of conductive strands and warp of LED fibers. The LED fibers have a conducting core, a first doped layer surrounding the core, and a second doped layer surrounding the first doped layer. The first and second doped layers form a light-emitting semiconductor junction. Each conductive strand electrically couples to each LED fiber at a respective lateral location, forming a light-emitting diode (LED) at each lateral location.
In another aspect consistent with the invention, a method of fabricating a light-emitting diode (LED) matrix includes making an LED fiber. The LED fiber is formed from a conducting core that is clad with a p-doped semiconductor to form an inner strand. Then, the inner strand is clad with an n-doped semiconductor. At least one of the p-doped semiconductor and n-doped semiconductor includes a light-emitting polymer so that the conducting a current at a lateral location on the LED fiber creates an LED.
These and other objects, advantages and features of the invention will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings.
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