TECHNICAL FIELD This invention relates generally to improvements in scrolling backlighting systems of the type used in display applications for motion artifact reduction and, more particularly, to the invention resides in apparatus for scrolling high intensity light from a source over a backlight panel for an LCD-TV display in a manner which overcomes problems normally associated with scrolling backlight systems.

The invention further relates to a panel comprising such a backlighting system.

BACKGROUND TECHNOLOGY In the transmitting mode of operation of a LCD, light emanating from an appropriate light source is directed to a panel located on the opposite side of the LCD display from the viewer.

In order to reduce motion artifacts in LCD-TV displays, it has been found useful to provide the light in such a manner that a beam is continually scrolled over the panel.

Presently, scrolling backlight systems used in the reduction of motion artifacts for LCD-TV use either direct backlight cold cathode fluorescent lamps (CCFLs) or edge-backlight white RGB (red, green, blue) LEDs, the latter of which requires substantially more power than the former. Both systems commonly experience undesirable characteristics such as non- uniformity of illumination over the area of the panel and/or brightness level.

The present invention is directed to overcoming one or more of the problems or disadvantages associated with the relevant technology.

SUMMARY OF THE INVENTION Light from an appropriate source is directed into a) a light source (10); b) rotating means (16, 30) for directing light into a plurality of optical wave guides (24) each having a proximal (24') and a distal (24") end; c) said proximal ends being arranged in facing relation to said rotating means.

d) said distal ends (24") being arranged linearly along one edge (26') of said panel (26) and e) motive means (28) for imparting rotation to said rotating means.

In one embodiment light is directed into the open end of a cylindrical drum, the other end of which is closed. The drum has a highly reflective inside surface and an orifice of predetermined dimensions in the cylindrical wall. The drum is rotated at constant angular velocity about its axis, causing the beam of light passing through the orifice to likewise rotate in a circular pattern. An array of optical fibers is arranged with a proximal end of each fiber positioned on a circle coaxial with the axis of the drum and spaced outwardly from the position on the drum's outer surface which includes the orifice. The distal ends of the fibers are positioned linearly along an edge of the backlighting panel of e. g. a LCD array with the distal ends in the same sequence as the proximal ends. Thus, the beam passes through the orifice and sequentially impinges upon the proximal ends of the fibers, and is thereby directed to and scrolled continuously across the panel to provide backlighting with a sufficient and uniform level of brightness.

In a further embodiment a transparent stating body directs the light beam into a stack of wave-guides, the distal ends of which are positioned along the edge of the backlighting panel of a transmissive display panel.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a somewhat diagrammatic, perspective view of certain elements of apparatus embodying the invention; and Figure 2 is a perspective view of portions of the apparatus of Figure 1, with one element in section, in combination with other elements which form a part of the invention.

Figure 3 is a perspective view of a further embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Referring now to the drawing, light emitted by high intensity light source 10 is directed by parabolic reflector 12 into open end 14 of drum 16. In projector applications a high intensity discharge lamp, such as a metal halide lamp, is preferred for light source 10, while in other applications a different type of bulb or lamp may be preferable. Cylindrical wall 18 concentrically surrounds drum axis X-X and end wall 20 closes the end opposite

open end 14. The internal surfaces of walls 18 and 20 are highly reflective and designed to guide light toward outcoupling orifice 22 in drum wall 18.

A plurality of incoupling fiber optic light guides 24 are positioned with the proximal end 24'of each guide positioned on a circle coaxial with axis X-X, in facing relation and close proximity to wall 18 in the plane of orifice 22. Distal ends 24"of guides 24 are connected to edge 26'of panel 26 in a linear array in the same sequence as proximal ends 24'are positioned about axis X-X. The number of guides 24 is preferably greater than the number of inches in the length of side 26'. For example, sixteen or more guides would be provided for a 15"panel, although this would of course be dependent upon details of panel design and light guide physical parameters.

FUNCTIONAL DESCRIPTION In operation, rotation is imparted to drum 16, e. g. , by motor 28, at a constant angular velocity Wr. Thus, the beam of light passing through orifice 22 is likewise rotated about axis X-X and sequentially scanned over ends 24'of fibers 24. The dimensions of orifice 22 and the positioning of fiber ends 24'are such that the beam is scanned across the full surface of each of the fiber ends, one at a time in the sequence 241-24n in which the ends are positioned about the drum. The light is conducted by the fibers to and through distal ends 24", which are arranged along edge 26'in the same sequence 241-24n, thereby providing scrolled backlighting to panel 26 with illumination at an acceptable level of uniform brightness.

In Figure 3 a plurality of incoupling wave guides 24 are positioned with the proximal end 24'of each guide positioned on top of each other in facing relation and close proximity to rotating prism 30. Distal ends 24"of guides 24 are connected to edge 26'of panel 26 in a linear array in the same way as described with reference to Figures 1,2.

In operation, rotation is imparted to prism 30, e. g. , by a motor at a constant angular velocity (arrow 31). Thus, the beam of light passing lens through 33 prism 30 is likewise rotated (arrow 34) about axis X-X and sequentially scanned over ends 24'of fibers 24. The dimensions and the positioning of wave guide ends 24'are such that the beam is scanned across the full surface of each of the wave guides ends, one at a time in the sequence 241-24n in which the ends are positioned on top of each other. The light is conducted by the wave guides to and through distal ends 24", which are arranged along edge 26'in the same sequence 241-24n thereby providing scrolled backlighting to panel 26 with illumination at an acceptable level of uniform brightness.

Instead of a (transparent) prism after elements like cubes or pentagons may be used.

Other aspects and features of the present invention can be obtained from a study of the drawings, the disclosure, and the appended claims. For instance, other transparent display effects may be used in panel 26.