Optical waveguides – Noncyclindrical or nonplanar shaped waveguide
Utility Patent
1998-07-08
2001-01-02
Lee, John D. (Department: 2874)
Optical waveguides
Noncyclindrical or nonplanar shaped waveguide
C385S133000, C385S901000, C362S560000, C362S576000, C362S581000, C362S582000
Utility Patent
active
06169839
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to light conducting and light emitting tubes, herein referred to as “light tubes”, and novel optical light films having an embossed prism pattern to contain and channel the light when formed into a tube. More particularly, the present invention is concerned with laminated tube construction and methods of constructing light tubes to achieve a wide range of illumination effects including the piping of light from an accessible, concentrated light source to distal areas and the release of such light in widely variable patterns.
Optical light films (OLFs) can be efficiently manufactured from polymers in flat, flexible, but fragile films and made to perform a myriad of illumination functions. The film can be formed into various tubular and other partially closed configurations by supporting it together with supplemental light controlling films or elements in preformed carrier tubing having light-permeable characteristics. For example, a sheet of OLF can be formed into a closed tube by disposing one longitudinal edge of the OLF adjacent the opposite longitudinal edge. Alternatively, a sheet of OLF can also be formed into a partially closed tube, for example having an arched cross-section, and maintained in such a configuration with a supporting structure. As used herein, the term “tube” is meant to include both closed and partially closed configurations.
In addition to carrying light from a source of illumination such as a high-intensity light bulb to a remote location, light tubes can also be used for emitting light over relatively large areas. For this purpose, various methods have been devised to direct light out of a light tube over portions of the tube length. One method involves placing a clear adhesive tape on the outer, grooved side of an optical light film. A clear soft tape, which preferably fills the grooves, reduces the internal reflectance of the optical light film in the taped area and essentially creates a window for “escaping” light. Another method simply involves removing a section of the optical light film where internal reflectance is not desired. Portions of a tube lacking optical light film will permit light to escape. A third method comprises forming a light tube with some means for directing the light at the walls of the optical light film at an angle greater than about 28°. At such angles of incidence, the internal reflectance of the optical light film is greatly reduced. For example, the 3M Company of St. Paul, Minn., produces a product marketed under the name “2370” which directs incident light at an angle of about 90° to the angle of incidence. If a piece of “2370” is positioned within a light tube, light moving generally along the longitudinal axis of the tube will be directed through the “2370” substantially perpendicular toward a sidewall and out of the light tube. Another product, marketed under the name “SCOTCH-CAL EXTRACTOR FILMS”, directs light toward and through an opposite interior wall.
Since optical light film is fragile and sensitive to dirt and moisture, it is typically positioned within protective, outer tubes. Such tubes are generally transparent and can have a variety of finishes, e.g. clear, matte, colored or opaque. The ability to insert the fragile optical light films into a carrier tubing, typically an extrusion product, is an impediment to the light tube designer. Moreover, shipping fabricated light tubes is costly because of their high volume relative to volume of component displacement and their inherent vulnerability to damage by breaking and scratching. Thus the low manufacturing cost of the critical optical film component is heavily offset by shipping costs. Also lost is the ability of the designer to achieve at acceptable cost finished products which feature many of the useful and underlying lighting functions which the optical light film is inherently capable of performing.
It would therefore be desirable to provide novel methods for forming light tubes and light tube products using the films which are cost effective, optically efficient and functionally varied.
SUMMARY OF THE INVENTION
The present invention comprises improvements in methods of forming light carriers and the resulting light carriers comprising optical light film.
One embodiment of the present invention comprises an optical light film formed with a generally U-shaped connector which, along with other elements, forms slots for securely receiving at least portions of the longitudinal edges of the optical light film. This embodiment advantageously permits on-site fabrication of light tube having substantially total (i.e. 360°) internal reflectance.
Another embodiment of the present invention comprises an improved optical light film which advantageously allows controlled amounts of light to exit the light tube without the need for supplemental extractors.
Another embodiment of the present invention comprises a decorative light fixture comprising a source of illumination, a light tube comprising OLF which emits light over the length of the tube and is also provided with an emitter for changing the direction of light exiting the distal end of the light tube.
A further aspect of the present invention comprises a novel, heat resistant connector which provides a durable connection between light tubes or portions of light tubes, for example between a optical light film tube and a bulb housing.
Another aspect of the present invention comprises a light tube comprising a tapering, optical light film tube. As explained in greater detail below, a substantially continuous illumination may be obtained over the length of a light tube by providing a carefully measured converging taper to the light tube in the direction extending away from the source of illumination.
Another decorative embodiment of the present invention comprises two sheets of optical light film positioned with the grooves in contact and with the grooves disposed at an angle of at least 45°, and most preferably at an angle of substantially 90°. This embodiment creates the decorative illusion of a flame in the light tube. Colored filters can be used to provide images of flames of different colors.
Another embodiment of the present invention comprises a first sheet of optical light film connected to an outer, protective sheet of a second material in an area remote from the edges of the two sheets. The opposing longitudinal edges of both sheets are configured such that the second edge of the optical light film is positioned between the first edge of optical light film and the first edge of the outer protective sheet while the second edge of the outer protective sheet is connected with a first edge region of the protective sheet. This light tube provides a sheet of optical light film substantially surrounded by an outer, protective sheet which facilitates maintaining the optical light film in a clean, dry and optically efficient condition.
Another aspect of the present invention comprises connecting two sheets in a manner similar to that described above and disposing at least one sheet of optical light film between the two sheets.
Another embodiment of the present invention provides light distribution systems and illumination devices which comprise a plurality of light distributing tubes comprising a plurality of sheets, and wherein at least one sheet of one light distributing tube overlaps a portion of at least one sheet of an adjacent light distributing tube.
Another embodiment of the present invention comprises novel ring connectors for use in connecting adjacent light distributing tubes and novel ring connectors for use in connecting a source of illumination to a light distributing tube.
Still another embodiment of the present invention comprises end caps for connecting an end of a light distributing tube to a lens, a colored filter, a mirror, or means for directing light.
A further embodiment of the present invention comprises an assembly for mounting a light distributing tube in a desired location, e.g., along a wall or suspended from a ceiling.
These and
Galgano & Burke
Lee John D.
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