This invention generally relates to light emitting members made of flat optical fibers that emit light received through one or both ends out one or both sides to provide a desired light output distribution.
It is generally known to make light emitting members out of light conducting panels, films, sheets, plates and optical fibers. Light entering one or both ends of the light emitting members may be emitted from one or both sides by providing disruptions on one or both sides in a desired pattern.
An advantage in making light emitting members out of panels, films, sheets and plates is that they are relatively inexpensive to make. However, such light emitting panels, films, sheets and plates are not as efficient in transmitting light as light emitting members made out of optical fibers because they lack the cladding that optical fibers have to keep the light in longer and allow the light to be distributed/emitted where desired. Also it is difficult to control the thickness of injection molded light emitting panels, films, sheets and plates because of the stresses that occur in different areas of the light emitting members during cooling after molding.
Heretofore a major drawback in making light emitting members out of optical fibers was the relatively high cost of manufacture. Also because the optical fibers used were round optical fibers of relatively small diameter, only a relatively small surface area of each optical fiber could be disrupted during the manufacturing process as compared to the amount of surface area of light emitting panels, films, sheets and plates that could be disrupted. This limited the relative overall brightness of light emitting members made of optical fibers as compared to light emitting panels, films, sheets and plates for a given light emitting surface area.
Another disadvantage of previous light emitting members made of optical fibers was that the ends of the optical fibers had to be bundled and secured together by a connector assembly that served as an interface between the optical fiber ends and a light source. Also it was difficult efficiently to couple a light source to such bundled optical fiber end portions because of the minute gaps between the optical fiber end portions and the irregular shape of the bundled optical fiber end portions.
There is thus a need for light emitting members that have the attributes of light emitting members made of both panels, films, sheets and plates and optical fibers.
The light emitting members of the present invention are made out of optical fibers instead of light emitting panels, films, sheets or plates for increased efficiency in keeping the light in longer and allowing the light to be distributed/emitted where desired. However, instead of using round optical fibers, flat optical fibers are used which have the advantage that more surface area of the flat optical fibers can be disrupted using known marring or abrading techniques for increased brightness for a given light emitting surface area.
Another advantage in making light emitting members out of flat optical fibers instead of round optical fibers is that the ends of the flat optical fibers need not be bundled and secured together by a connector assembly to serve as an interface between the fiber ends and the light source as do round optical fibers. Flat optical fibers may be manufactured in different thicknesses and widths to make it easier and more efficient to couple one or more light sources including particularly surface mount light sources such as surface mount light emitting diodes to the flat optical fiber ends. Surface mount light emitting diodes are generally rectangular in cross section, which makes it relatively easy to optically couple them to the ends of flat optical fibers by making the flat optical fibers of substantially the same thickness and either the same or greater width than the light sources. If the flat optical fibers have a width substantially greater than that of the light sources, multiple light sources may be optically coupled to the end of each optical fiber to provide for increased brightness. Also because the ends of the flat optical fibers need not be bundled together by a connector assembly to serve as an interface between the optical fiber ends and the light sources, the need for space to receive and store bundled round optical fiber ends is eliminated.
Still another advantage in making light emitting members out of flat optical fibers instead of round optical fibers is that a fewer number of wider flat optical fibers may be used to produce an equivalent light output. Flat optical fiber light emitters may be comprised of one or more flat optical fibers depending on the light output requirements of the light emitters. Where multiple flat optical fibers are used, the flat optical fibers may be held together or mounted separately and may if desired have gaps therebetween for lighting different areas of a display including for example a liquid crystal display, a graphic overlay or different rows of keys of a keyboard or the like.
In accordance with one aspect of the invention, the light emitting members comprise one or more flat cladded optical fibers having disruptions along at least a portion of their length to cause conducted light to be emitted from at least one of the sides.
In accordance with another aspect of the invention, the disruptions may be formed in one or both sides of the flat optical fibers by roughening, marring, abrading, etching, grit blasting or thermoforming one or both sides of the flat optical fibers.
In accordance with another aspect of the invention, the disruptions may be formed in a single inline process.
In accordance with another aspect of the invention, the light emitting members may comprise a plurality of flat optical fibers held together by an adhesive film or by mechanical clips or fasteners.
In accordance with another aspect of the invention, the flat optical fibers may have gaps therebetween for backlighting different areas of a keyboard or other type of display.
In accordance with another aspect of the invention, the thickness of the flat optical fibers may substantially correspond to the thickness of the light sources including particularly surface mount light sources such as surface mount light emitting diodes (including polymer light emitting diodes and organic light emitting diodes) for ease of optically coupling the light sources to the flat optical fibers.
In accordance with another aspect of the invention, the flat optical fibers may be of different widths which may be the same or greater than the width of the light sources. If the width of the flat optical fibers is substantially greater than that of the light sources, multiple light sources may be optically coupled to each flat optical fiber for increased brightness.
These and other objects, advantages, features and aspects of the invention will become apparent as the following description proceeds.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter more fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but several of the various ways in which the principles of the invention may be employed.
In the annexed drawings:
Referring now in detail to the drawings, wherein the same reference numbers are used to designate like parts, and initially to
To cause conducted light entering one or both ends of one or more flat optical fibers 1 to be emitted from one or both sides 2 and 3 thereof, the flat optical fibers may be disrupted at one or more areas along their length as by roughening, marring, abrading, etching, grit blasting or thermally deforming one or both sides.
One or more flexible flat optical fibers of any desired length may be wound on a spool or spindle (not shown) for ease of handling and storage and pulled off the spool and passed between a pair of opposed pressure rollers to provide disruptions 12 on one or both sides of the fibers. In
The size, depth, density and/or location of the disruptions 12 in one or both sides of the flat optical fibers may be varied as desired as by moving the rollers toward and away from each other during the marring or abrading process to cause conducted light to be emitted from one or both sides of the fibers in a uniform or non-uniform pattern as desired.
A reflective coating may be directly applied in intimate contact to the cladding surface 9 on one side of the flat optical fibers 1 to act as a back reflector for reflecting the conducted light toward the opposite side.
The size (including thickness, width and length) of the flat optical fibers as well as the number of flat optical fibers used to make a particular light emitting member in accordance with the present invention may be varied depending on the particular application, as may the size, type and number of light sources used to supply light to one or both ends of the flat optical fibers. However, the flat optical fibers used to make a particular light emitting member will typically have a thickness of between 0.010 inch and 0.035 inch and a width of between 0.070 inch and 3 inches, with a ratio of thickness to width of less than 0.5. Also the flat optical fibers will typically have a length greater than 5 inches, with a ratio of thickness to length of less than 0.007.
For example, the surface mount type LED 30 may have a rectangular cross-sectional shape with a thickness of approximately 0.030 inch and a width of approximately 0.200 inch, and the flat optical fibers 1 may have substantially the same thickness as the LEDs and either substantially the same width as the LEDs for optically coupling one LED to an end of each flat optical fiber as shown in
One or more light sources 30 may be attached to an end of one or more flat optical fibers 1 by a mechanical clip or fastener 31 as shown in
It is also important to polish the ends of the flat optical fibers to which the light sources are optically coupled for more efficient coupling of the light to the ends of the optical fibers. Moreover, the ends of the flat optical fibers 1 that receive light from one or more light sources may either be substantially flat as schematically shown at 35 in
A heat sink 41 may be placed in close proximity to the light source 30 adjacent an end of a flat optical fiber light emitting member 42 as schematically shown in
Where the light emitting members are comprised of a plurality of flat optical fibers, the spacing between the flat optical fibers may be varied as desired to suit a particular application. For example, where such a light emitting member 50 is used to backlight a keypad 51 having a plurality of rows of keys 52, suitable gaps 53 may be provided between the flat optical fibers 1 substantially corresponding to the spacing between a plurality of rows of the keys so the flat optical fibers extend behind a plurality of rows of the keys as schematically shown in
Moreover, the light emitting member 60 may be comprised of a single flat optical fiber 1 having a desired width and length corresponding to the width and length of a portion of a medical instrument 61 such as a retractor blade 62 as schematically shown in
Although the invention has been shown and described with respect to certain embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of the specification. In particular, with regard to the various functions performed by the above described components, the terms (including any reference to a “means”) used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed component which performs the function in the herein illustrated exemplary embodiments of the invention. In addition, while a particular feature of the invention may have been disclosed with respect to only one embodiment, such feature may be combined with one or more other features as may be desired or advantageous for any given or particular application.
This application is a division of U.S. patent application Ser. No. 10/900,000, filed Jul. 27, 2004, the entire disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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Parent | 10900000 | Jul 2004 | US |
Child | 12031740 | US |