Illumination – Plural light sources – With modifier
Reexamination Certificate
2000-03-13
2001-09-04
O'Shea, Sandra (Department: 2875)
Illumination
Plural light sources
With modifier
C362S800000, C362S369000, C362S288000, C362S249070, C362S244000, C362S241000, C362S223000, C362S217060
Reexamination Certificate
active
06283612
ABSTRACT:
TECHNICAL FIELD
The present invention relates to light strips in general. More specifically to a light strip having diodes mounted on a printed circuit board disposed within a transparent or translucent tube.
BACKGROUND ART
Previously, many types of light strips have been used in endeavoring to provide an effective means to produce light with a minimum amount of heat. Some prior art has been developed that places a series of light emitting diodes in various tubes or bulbs with reflectors for maximizing the light emitted. Others have used liquid inside the tube along with the light emitting diodes to transmit the heat to the outside surface. Standard light bulb bases have been used for connection to sockets and others have utilized couplings for attachment together forming a long lamp assembly.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however the following U.S. patents are considered related:
U.S. Pat. No.
Inventor
Issue Date
5,890,794
Abtahi et al.
Apr. 6. 1999
5,688,041
Arndt
Nov. 18, 1997
5,655,830
Ruskouski
Aug. 12, 1997
5,607,227
Yasumoto et al.
Mar. 4, 1997
5,367,441
Wustich
Nov. 22, 1994
4,941,072
Yasumoto et al.
Jul. 10, 1990
4,748,545
Schmitt
May 31, 1988
Abtahi et al. in U.S. Pat. No. 5,890,794 teaches a light unit having a flexible circuit board with a number of LED's extending outward from the front side and is covered with a transparent cover forming an outer cavity. The printed circuit board is supported by the housing in which a second cavity is formed. In a second embodiment the board is rigid and the LED's extend outwardly. In either case the outer cavity is filled with liquid for cooling.
U.S. Pat. No. 5,688,041 issued to Arndt is for a lighting device consisting of a string of LED's in a circuit which is housed within a hollow transparent tube. Each axial end of the tube is equipped with a coupling permitting a detachable connection of another lamp assembly.
U.S. Pat. No. 5,655,830 of Ruskouski discloses a lighting system having a lamp assembly made of a hollow translucent or transparent tube connected to a standard light bulb base. Inside the tube are housed, a series connected string of light emitting diodes, various resistors and a capacitor also a surge suppression device. The LED'S may be either discrete type or the die-on type mounted on one or both sides of a printed circuit board.
U.S. Pat. No. 5,367,441 Wustich discloses an illuminating device used as a background surface of a display with a circuit board having LED's and inner reflecting surfaces. The circuit board is made of a light-transmissive material and serves as the background surface to be illuminated. The circuit board leads and LED's are connected for controllability and a scattering body of light-transmissive potting compound fills the interior of a frame. The scattering centers are in the form of glass particles.
U.S. Pat. No. 4,748,545 Schmitt discloses an illumination system for a display cabinet having a plurality of low voltage lamps in a clear cylindrical housing. An air space between a reflector and the housing provide thermal insulation preventing overheating in a display cabinet.
For background purposes and as indicative of the art to which the invention is related, reference may be made to the remaining cited patents issued to Yasumoto et al. in both U.S. Pat. Nos. 5,607,227 and 4,941,072 which are directed to linear light sources consisting of an integrated lens and reflective frames for housing a base plate with LED's arranged in a line.
DISCLOSURE OF THE INVENTION
Light strips of one type or the other have been in use for some time with the most popular being the fluorescent tube type which has utility in a wide variety of applications, however, it also has its limitations as the ballast must be included in the fixture making the entire light rather large relative to the size of the lamp. It is therefore a primary object of the invention to have a light strip that uses solid state light emitting diodes and is only the size of its transparent or translucent enclosing tube. The invention requires only a single power supply that will energize up to 350 LED's in the white configuration and 700 colored devices, permitting the use of a large number of strips with a single power supply.
An important object of the invention is that the use of LED's reduces power consumption to a bare minimum as each device uses only 0.0124 Watts of power and is extremely efficient as far as illumination is concerned. The normal procedure for determining the effectiveness of each type of illuminating device is to compare the efficiency of the light source in terms of the amount of light produced in relation to the amount of power consumed. This relationship is expressed in lumens per watt or (LPW). For general comparison an incandescent light has an index of less than 24, a halogen lamp is only slightly better at 25, a mercury vapor is around 65 and a fluorescent lamp is in the neighborhood of 75 according to the type, whereas a light emitting diode (LED) in the T 1 ¾ style has a rating of almost 89.
Another object of the invention is that it is cool in operation which makes the light ideal for applications such as lighting candy displays in stores and markets. It has been found by actual usage that a two foot long light strip having 24 diodes has a temperature rise of only ten degrees F.(5.6 degrees C.) at a prevailing ambient temperature of 70 degrees F. (21.1 degrees C.) within the confines of a typical display cabinet. This advantage may be utilized in a host of other applications as the light strip is not hot to the touch and therefore may be used safely around people particularly children.
Still another object of the invention is the life of the LED compared to other light sources. Data available, generally indicates that a common incandescent lamp has a life expectancy of somewhere around 2,000 hours and a fluorescent lamp may last in the 10,000 hour range. The life of a light emitting diode is ten times better than that of the fluorescent lamp in that the life of a LED is approximately 100,000 hours. This means that a LED could operate continuously for a period of over eleven years before failure would be expected.
Yet another object of the invention is directed to its small physical size. It may be clearly seen that the light strip may be used in place of a fluorescent lamp with a comparable size bulb as no ballast is required adjacent to the lamp and the power supply may be positioned in a remote location preferably near a city power source such as a convenience outlet in a wall. Further since the light strip uses low voltage direct current power the wiring is considerably smaller and is not subject to local codes as a matter of fact the national electric code (NEC) classifies this type of wiring as Class 2 which excludes it from most strict city power local codes. It has been found that number 22 American Wire Gauge (AWG) is completely adequate for the application and is considerably smaller and easier to handle than normal 120 volt AC wire.
A further object of the invention is the sturdiness of the device as the LED's are solidly mounted in a circuit board which in turn is held captive in a hollow thermoplastic tube permitting it to be completely vibration resistant. Further the tube is plugged on each end with a clear plastic end cap and the wire penetrating the cap is potted or sealed in such a manner as to make the invention waterproof. These two features make a strong and robust light strip compared to incandescent lamps that are subject to damage with vibration and fluorescent lamps that are fragile and dangerous to handle.
A final object of the invention is the ease of installation of the light strip as a U-shaped channel base, fabricated of an extruded plastic, may be attached to an object with adhesive or conventional fasteners and the light strip snapped into place between the upstanding legs of the channel. Since the invention is relatively light in w
Anderson Gordon K.
Lee Guiyoung
O'Shea Sandra
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