Patent Application
20100294001
This invention relates to transparent light emitting members that have specially shaped notches or grooves in one or more surfaces to create a selected light output distribution from such members and their method of manufacture.
It is well known that light transparent members including for example rods, panels, films, sheets and plates, can be made into light emitting members or illuminators by notching the members in a certain pattern. However, such notches are typically relatively sharp grooves, which do not scatter light very finely. Also the sharp grooves make the light emitting members more susceptible to breakage during installation or when placed under tension. The light emitting members may be used, for example, as a back light and/or front light for transparent or translucent devices such as LCDs, dials, gauges, pictures, point of sale advertising, decorative devices, and so on. Also such light emitting members may have special usages in optical scanning and array devices and the like.
In accordance with one aspect of the invention, the light emitting members have rounded shallow notches or grooves in one or more surfaces that scatter the light emitted from the members.
In accordance with another aspect of the invention, the rounded shallow notches or grooves reduce the risk of breakage of the light emitting members during installation or when the members are placed under tension.
In accordance with another aspect of the invention, the notches or grooves are generally U or C shaped.
In accordance with another aspect of the invention, the light emitting members with rounded shallow notches or grooves are relatively inexpensive and easy to manufacture.
In accordance with another aspect of the invention, the light emitting members with rounded shallow notches or grooves allow for easy low volume manufacturability of the members with any desired amount of smoothness or roughness on the faces of the notches or grooves.
In accordance with still another aspect of the invention, the light emitting members may have special arcuate shapes for use in special lighting applications.
In accordance with still another aspect of the invention, the light emitting members may comprise one or more flat optical fibers having a pattern of shallow U or C shaped notches or grooves along at least a portion of the length of the fibers to cause conducted light to be emitted from the fibers.
In accordance with another aspect of the invention, a laser may be used to cut a pattern of U or C shaped notches or grooves in at least one side of the light emitting members.
In accordance with another aspect of the invention, the laser may be coupled to an X-Y table on which the light emitting members are supported to cut a prescribed pattern of the notches or grooves in the light emitting members.
In accordance with another aspect of the invention, the laser may be intermittently pulsed, and the laser and light emitting members may be moved relative to one another in an X and/or Y direction between pulses to cut a plurality of spaced apart notches or grooves in the light emitting members.
In accordance with another aspect of the invention, the laser may be controlled to vary the depth, width, spacing, relative position, diameter, and/or surface finish of the notches or grooves in the pattern to control the amount of light extracted from the light emitting members by the notches or grooves.
In accordance with another aspect of the invention, the laser may be moved at a substantially constant speed relative to the light emitting members during continuous pulsing of the laser to cut relatively uniform single depth notches or grooves in the light emitting members.
In accordance with another aspect of the invention, the laser may be moved at a variable speed relative to the light emitting members during continuous pulsing of the laser to cut relatively long variable depth grooves in the light emitting members.
In accordance with another aspect of the invention, the laser may be moved at a substantially constant speed relative to the light emitting members while the laser is intermittently pulsed to cut a plurality of grooves having substantially the same depth in the light emitting members.
In accordance with another aspect of the invention, the laser may be de-focused during laser pulsing to provide the notches or grooves with a roughened or bubbled surface finish.
In accordance with another aspect of the invention, the diameter of the laser beam may be varied during laser pulsing to vary the width of the notches or grooves along their length to cause more or less transmitted light to be extracted from the light emitting members.
In accordance with another aspect of the invention, the laser power level may be varied during laser pulsing to vary the width and depth of the notches or grooves.
These and other aspects of the present 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 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:
a and 4b are schematic fragmentary side elevation views of an end portion of a light emitting member of the present invention showing alternative ways of optically coupling a light source to an edge of the member.
Referring now in detail to the drawings, and initially to
Such light emitting members may be molded or cast or machined or cut out of any suitable transparent, clear or colored (including scintillating or fluorescent) material including glass or plastic such as acrylic, polycarbonate, styrene, or urethane or the like. The notches or grooves 3 may be painted or covered with a reflective color. Also, different notches may be coated with different colors for decorative or visibility purposes when the light emitting member is lighted by one or more white light sources.
Such light emitting members may be lighted from one or both end edges using any suitable light source 5. The rod-like light emitting member 2 of
The light source 5 may also be held adjacent an edge of light emitting member 1 using for example a few drops of adhesive, or by heat shrinking a heat-shrinkable tube 10 around both the light source 5 and an edge of the light emitting member 1 as schematically shown in
If LEDs are used as the light source, suitable holes 7 may be molded or cast in one or more edges of the light emitting member for receipt of the LEDs as schematically shown in
Using LEDs as the light source has the benefit that LEDs produce very little heat, consume small amounts of electric power, have a relatively long life, are relatively inexpensive, are not damaged by vibration, and do not produce EMI. However, other types of light sources may also be used including, for example, an arc lamp, an incandescent bulb, a lens end bulb, a line light, a halogen lamp, a neon bulb, a fluorescent tube, a fiber optic light pipe transmitting from a remote source, a laser or laser diode, or any other suitable light source.
The density and/or depth or size of the notches 3 may be varied along the surface of the light emitting member 1 in order to obtain a selected light output distribution from the member. For example, the amount of light traveling through the light emitting member will ordinarily be greater in areas closer to the light source than in areas further removed from the light source. The pattern of notches or grooves 3 may be used to adjust for the light variances within the light emitting member, for example, by placing the notches 3 closer together as the distance from the light source increases to provide a more uniform light output distribution from the light emitting member. Also, depending on the length and cross-sectional thickness of the light emitting member, the notches 3 may be made progressively deeper and/or wider with increased distance from the light source to provide a more uniform light output from the member.
When the light emitting member is lighted from one end only as shown in
A reflective film or coating 15 may be provided on the non-lighted end edge of the light emitting member (if lighted from only one end edge as schematically shown in
The light emitting member 1 may also be lighted from both ends as schematically shown in
If a non-angular light output is desired, a rectangular cross-sectional shape 19 as shown in
If the light emitting member 1 of
If the light emitting member 1 of
The light emitting member may also comprise one or more optical fibers for increased efficiency in keeping the light in longer and allowing the light to be distributed/emitted where desired. Moreover, instead of using round optical fibers, the optical fibers may be flat. Using flat optical fibers has the advantage that more surface area of the optical fibers can be disrupted using known marring or braiding techniques for increased brightness for a given light emitting surface area.
Another advantage of using 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 the 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 source, 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. A unique quality of a single flat optical fiber is that it can be cut to a curved, rounded or angled configuration if desired.
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, graphic display or different rows of keys of a keyboard or the like as disclosed, for example, in U.S. patent application Ser. No. 10/900,000, the entire disclosure of which is incorporated herein by reference.
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. For example, the flat optical fibers used to make a particular light emitting member may have a thickness of between 0.010 inch and 0.035 inch or even between 0.004 inch and 0.010 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. However, for certain applications such as cell phones, the flat optical fibers may have a shorter length, for example, 1 to 3 inches. Also, the flat optical fibers may be made sufficiently flexible for use in activating a switch.
For example, the surface mount type LED 45 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 28 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 of the light sources 45 may be attached to an end of one or more flat optical fibers 28 by a mechanical clip or other type fastener 46 as shown in
To cause conducted light entering one or both ends of one or more of any of the light emitting members of the present invention to be emitted from one or more sides thereof, the rounded shallow U shaped notches or grooves similar to those shown in
Alternatively, a laser may be used to cut a pattern of generally U shaped notches or grooves in one or more sides of the light emitting members.
Laser 47 includes a mirrored laser head 49 that cuts the notches or grooves in a prescribed pattern in the light guide, and may be coupled to an X-Y table 50 on which the light guide is supported during the cutting operation.
Laser 47 may include one or more of the following control factors to cut the notches or grooves in a prescribed pattern in the light guide: variable focus, variable power level, variable beam diameter, variable pulse duration, variable direction of laser pulsing relative to direction of transmitted light in the light guide; and variable speed cutting laser head or table. For example, one or more of the control factors may be varied in a predetermined manner to vary the cut, size, finish and/or placement of the notches or grooves 3 in the light guide. Also the laser 47 may be controlled to vary the depth, width, spacing, relative position, diameter and/or surface finish of the notches or grooves in the pattern to control the amount of light extracted from the light guide 47 by the notches or grooves. Moreover, the laser 47 may be controlled so that the notches or grooves in the pattern closest to the lighted end are made relatively parallel to the light emitting member to cause a relatively small percentage of the transmitted light to be emitted and the notches or grooves further removed from the lighted end may be made to run at an angle to the direction of the transmitted light and finally perpendicular to the direction of the transmitted light as the distance from the lighted end increases as shown in
Laser 47 may also be intermittently pulsed and the laser and light guide may be moved relative to one another in the X and/or Y direction between pulses to cut a plurality of spaced apart notches or grooves 3 in the light guide as shown in
A portion of the surface of the light guide may also be coated with a masking material 55, and a pattern of shallow U shaped notches or grooves 3 may be laser cut in the unmasked areas 56 of the surface as shown in
Where the light guide is an optical fiber including a light conducting core and a cladding surrounding the core, the notches or grooves may extend through the cladding and at least part way through the core. Also, regardless of the shape of the light emitting members, the notches or grooves may be provided on more than one side of the members as desired. Moreover, any of the light emitting members of the present invention may be curved along their length to suit a particular application.
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 a 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. Also, all of the disclosed functions may be computerized and automated as desired. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several embodiments, such feature may be combined with one or more other features of the other embodiments as may be desired and advantageous for any given or particular application.
This application is a division of U.S. patent application Ser. No. 11/768,230, filed Jun. 26, 2007, which is a continuation-in-part of U.S. patent application Ser. No. 10/900,000, filed Jul. 27, 2004, now U.S. Pat. No. 7,406,245, dated Jul. 29, 2008, and a continuation-in-part of U.S. patent application Ser. No. 11/126,655, filed May 11, 2005, now abandoned, which is a division of U.S. patent application Ser. No. 10/264,576, filed Oct. 4, 2002, now U.S. Pat. No. 6,910,783, dated Jun. 28, 2005.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11768230 | Jun 2007 | US |
| Child | 12846929 | US | |
| Parent | 10264576 | Oct 2002 | US |
| Child | 11126655 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10900000 | Jul 2004 | US |
| Child | 11768230 | US | |
| Parent | 11126655 | May 2005 | US |
| Child | 10900000 | US |
