Visible perception of brightness in miniature bulbs for an ornamental lighting circuit

Ornamental light strings are commonly made of a plurality of miniature light bulbs connected together, often in series, to make a light string. This invention is directed to optimizing the perceived brightness while reducing heat in each bulb. This is a particular problem where resistor bypass circuits are used where a bypass resistor being connected in parallel with at least one of the respective light sources, each respective light source being low wattage and being capable operating on a one hundred percent duty cycle as desired. Improvements are accomplished by changes in placement of the filament, its windings and materials.

TECHNICAL FIELD OF THE INVENTION

The present invention is generally related to an improved light circuit for series circuits or series-parallel circuits utilizing incandescent, LED, or other types of lighting sources, and more particularly, the present invention relates to a resistive bypass element that will continue to conduct electricity and keep the remainder of the series circuit of lights lit even when one or more individual lighting elements are burnt out, defective, broken, have a loose connection or a broken connection in the series circuit, including series parallel circuits.

BACKGROUND OF THE INVENTION

Series connected circuits containing lighting sources are well known especially in lighting strings and flexible lighting (Rope Lights) around the holidays when such light strings are used for decorative purposes. More recently, series connected lighting sources are becoming popular in task lighting, general illumination, automotive lighting, and specialty lighting utilizing LEDs. Generally, the lights in these lighting circuits are electrically in series rather than in parallel. One particular drawback to these types of lighting circuits is that when a lighting source is removed from the circuit, is burnt out, defective, or has a loose connection, the entire lighting circuit is rendered inoperable. Each lighting element within the circuit completes the electrical circuit, so when a light source is removed (for a replaceable type), a connection becomes loose, or the lighting element burns out or other lighting component within the light source, a gap is created in the circuit and electricity is unable to continue to flow through the circuit. When a “good” light source is inserted into the circuit or socket, it completes the circuit, thus allowing electricity to flow uninterrupted.

Specifically, Fisherman, U.S. Pat. No. 2,760,120, discloses a series circuit for a light set with individual incandescent flasher or twinkle bulbs that include a bypass resistor in parallel with the bulb element. The operation of the Fisherman light set is limited to a set with a bulb that flashes on and off, a duty cycle of less than 100%. The on time of the bulb is necessary to control heat generation in the resistor, the resistor conducting during the off time of the bulb, thereby regulating the heat produced in the resistor circuit. The Fisherman device cannot be applied to a set wherein a bulb is burnt out, removed, or loose (and not conducting) to continue to illuminate the remaining bulbs in the circuit. In such situation, the bypass resistor is continually conducting and the temperatures generated on any bypass resistor of practical size (let alone one that fits into a socket) will far exceed ignition temperatures of near by materials used in construction of the set. Further, the Fisherman bulb is a high energy bulb, being 8 volt and ¼ amp, for a power consumption of 2 watts. A more energy efficient bulb is in demand at the present time. Presently, bulbs, such as that depicted generally at500in prior artFIG. 15, are utilized. Such bulbs are a considerable improvement when compared to the Fisherman bulb, having 0.35-0.425 watt power consumption. There is still a need in the industry for a more energy efficient bulb.

While previous mechanical and electrical circuit configurations have been used in an attempt to address the problems described above, none do so with the reliability, simplicity, low cost of the present invention, and reduced energy consumption. The difficulties and drawbacks of previous lighting series circuit configurations are overcome by the resistive bypass for a series light circuit of the present invention.

SUMMARY OF THE INVENTION

The systems and methods of the invention have several features, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the invention as expressed by the claims which follow, its more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description of the Drawings” one will understand how the features of the light unit for a light string provide several advantages over traditional series light circuit.

Accordingly, it is an object of the present invention to provide a novel and improved bypass circuit for a series light circuit configuration capable of keeping uninterrupted current flow on condition that a light source of the circuit is removed, becomes loose, fails to conduct, or lighting element or other lighting device of the light source burns out, or becomes defective within the light source.

A further object of the present invention is to provide an incandescent bulb of reduced energy consumption while at the same time maintaining the level of brightness apparent to the human eye as is produced by current higher energy consuming bulbs (the standard bulb having a power consumption of 0.35-0.425 watts). The present invention utilizes bulbs that are less than 0.25 watts and are more preferably 0.20 watts. In order to achieve substantially the same brightness as the standard bulb, the bulb of the present invention uses a higher purity tungsten filament, along with a tighter coil for the filament when rated 0.20 watts. Further, to improve the brightness, the filament is placed higher into the bulb canopy, so that losses from the plastic bulb adaptor at the bottom of the bulb do not absorb as much light. This provides for a measurably brighter bulb, and also provides to the human eye an even apparently brighter bulb, as the filament is higher up into the bulb, something that hasn't been done in the industry to date. Such bulbs can be utilized with a duty cycle of 100% and, when disabled, the conducting bypass resistor in the circuit of the present invention does not achieve dangerous temperature levels due to the reduced current flow. The Fisherman device is necessarily restricted to employment with flasher bulbs, and these must be used in a set where the bulbs are never fully off (disabled) so that the bypass resistor is not continually conducting.

Another object of the present invention is to provide the ability to allow for semiconductor light sources, such as light emitting diodes (LEDs), to provide a twinkling affect, by utilizing LED packages that incorporate integrated circuits (ICs) or other types of electronic circuits that control the flashing rate of the light source, which would only effect the individual lighting element as the resistive bypass would allow current to continue to flow in remaining lighting elements in the series circuit. In another embodiment of the invention, one or more semiconductor light sources, each with a flashing circuit, but without an associated bypass element in parallel, can be located in the lighting circuit in order to flash all the remaining light sources in the series circuit.

In yet another embodiment of the invention, one or more incandescent light sources, each with a flashing device, but without an associated bypass element in parallel, can be located in the lighting circuit in order to flash all the remaining light sources in the circuit.

Yet another object of the present invention is to provide the ability to allow for semiconductor light sources, such as LEDs, to provide color changing characteristics by utilizing LED packages that incorporate two or more LED chips, and an IC, or other electronic circuit, that controls each LED chip in the LED package independently, while the electronic circuit or IC controls the current and/or voltage to the individual LEDs in the LED package, allowing for the mixing of the LED chip colors to get various resultant colors, which would only affect the individual lighting element as the resistive bypass would allow current to continue to flow in remaining lighting elements in the series circuit. Those skilled in the art would also recognize that a zener diode could be used in parallel to the light source and bypass circuit to help regulate the voltage across the light source.

Further objects and features of the invention will be readily apparent to those skilled in the art from the following specification which includes the appended claims and drawings.

To achieve the above objects and in accordance with the purpose of the invention, as embodied and broadly described herein, one embodiment of a light circuit for a series lighting circuit of the present invention comprises lighting sources connected in series with each other, where each lighting source has a resistive bypass element connected in parallel across it.

The embodiment of this device is to provide a low cost resistive bypass element for series connected light sources. The current movement towards low energy incandescent bulbs, LEDs, and other energy saving light sources allows for a simple resistor to be utilized without creating the heating issues previously faced if such a device was attempted. Now with these low power consuming lighting sources, a resistive bypass element becomes the forefront of products, providing a low-cost bypass circuit.

In addition, the use of the resistive bypass element in series connected lighting circuits enables longevity and durability to continue without affect from the failure of any single light source due to defect, or connection issues.

In another embodiment of the present invention, the resistive bypass element may be connected in parallel with more than one light source, where the failure of one bulb would then only affect a limited amount of light sources in the lighting circuit, further saving the cost of bypass resistive elements across each lighting source.

In another embodiment of the present invention, a resistive bypass circuit allows for other types of lighting effects, such as twinkle type products where a semiconductor light source can utilize miniature ICs inside a lighting package, and will only affect that lighting source, allowing the remaining light sources to function independently. Also, more than one light package may have the twinkling effect. For this embodiment, the resistive bypass may only be used across those twinkling effect light sources, as an additional embodiment, or may be used across all lighting sources.

One more embodiment of the resistive bypass circuit is that it also allows for the use of color changing LED packages, that utilize more than one LED chip inside, and may consist of an IC controlled mixing of the LED chips to create other resultant colors, and will only effect that lighting source, allowing the remaining light sources to function independently. Also, more than one light package may have this color changing effect. For this embodiment, the resistive bypass may only be used across those color changing light sources, as an additional embodiment, or may be used across all lighting sources.

The series circuits above with bypass resistors, can also be employed in series—parallel circuits, and be employed in products with or without lampholders, including directly connected to printed circuit boards, as other embodiments of the invention.

The present invention has numerous features and advantages associated therewith.

The bypass circuit of the present invention herein described has an advantage of keeping the remainder of lights within a series lighting circuit lit when a light source is missing from, or becomes loose in, one or more light source sockets or circuits, or becomes defective. This is accomplished by continuing to conduct electricity through the series light circuit even when a light source is broken, loose, poor connection, or defective light source.

The bypass circuit can be utilized in AC or DC circuits powered by batteries, step down transformers, AC utility power, or converters from AC to DC or DC to AC power, pulsed DC, and filtered or unfiltered DC.

As will be realized, the invention is capable of other and different embodiments and its several details are capable of modifications in various respects, all without departing from the invention. Accordingly, the drawing and description are to be regarded as illustrative and not restrictive.

Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of preferred embodiment of the present invention with the attached drawings. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention, in which:

DETAILED DESCRIPTION OF THE DRAWINGS

The resistive bypass circuit10, being a set or sting of lights, as shown inFIG. 1includes a power source12, light sources14, and bypass resistors16. Power source12is shown inFIG. 1is a 120 volt alternating current (AC) power source, power source can be any voltage AC, direct current (DC), AC converted to DC, or DC converted to AC, both filtered or unfiltered DC, and pulsating DC or any other power source that can power the lighting sources. Light sources14may include incandescent bulbs, LEDs, or other lighting devices. Light sources14ofFIG. 1are incandescent bulbs.

Bypass resistors16are configured in parallel with light sources14, and combinations of bypass resistors16and light sources14are configured in series. Light sources14and bypass resistors16may be packaged together into light source assemblies18. When all light sources14are operating properly, a portion of the total current flowing through bypass circuit10flows through light source14, while the remainder flows through bypass resistor16.

In the event that a light source14ceases to conduct, and current flow is interrupted through that light source14, the total current will flow through its corresponding bypass resistor16. A missing, broken, or improperly connected light source14may cause a light source14to fail to conduct. In the case where light source14is an incandescent bulb, filament failure, or burnout, may be the cause of a light source failing to conduct. Without bypass resistors16operating in parallel with light sources14, any failure in a light source14would interrupt power to all other light sources14. The values of bypass resistors16are typically the same, and are chosen such that an appropriate current flows through light sources14when all light sources are operating properly.

FIG. 2illustrates another embodiment of the present invention that uses LEDs as a light source. Resistive bypass circuit20includes power source12, light sources26, optional current limiting resistors24, and bypass resistor28. Light sources26, optional current limiting resistors24, and bypass resistors28may be packaged together into light source assemblies22. In the embodiment shown inFIG. 2, light source26is a single LED, preferably of equal to or less than 0.25 W. In other embodiments, light source26may be an LED chip that includes more than one LED. Those skilled-in-the-art will appreciate that the value of current limiting resistors24will be chosen based on the type of light source26, the number of light sources26, the number of bypass resistors24, and the number and value of bypass resistors28.

In the embodiment shown inFIG. 2, power source12provides power to bypass circuit20. When all light sources26are operable, current flows through the circuit, with a portion of the total current flows through the path containing current limiting resistor24and light source26, while the remainder flows through bypass resistor28. When current flow is interrupted through a light source26, total current flows through the corresponding bypass resistor28, allowing the remaining light sources26to operate.

Resistive bypass circuits10and20may be used with any series, or series-parallel connected lighting device where failure of the bulb or its connection will turn off some or all of the bulbs. This includes mini-bulb lighting strings used for Christmas and other holiday decorative lighting, rope lights (also known as flexible lighting) and other general lighting applications that use series connected lamps or LEDs, such as a LED desk lamp, or under-counter light.

FIGS. 2a-2cshow various configurations and locations of the current limiting resistor and series and series-parallel configurations ofFIG. 2.FIGS. 2aand2b, show light source assemblies,22, that contain only the light source,26, and the bypass resistor,28, with the current limiting resistor located outside of the light source assembly22.

FIG. 2Dshows a circuit diagram utilizing a filtered full wave rectifier,82with an optional filter capacitor84. The full wave rectifier could be replaced by a single rectifier diode,76, to produce ½ wave rectification, and can be optionally filtered by capacitor84. If a large enough capacitor84is selected, utilizing a single diode,76, it could simulate full wave rectification to the circuit.

It was desired to utilize incandescent bulbs with the resistive bypass circuit10as shown inFIG. 1. In order to make the resistor set10work with modern, high temperature materials, it was needed to reduce the wattage of the bulbs to at least 0.25 W (standard bulbs in the industry are either the common 0.425 W bulb, or the less common 0.35 W bulb, as noted in prior artFIG. 15), but it is preferable to use 0.20 Watts. Sets using 0.25 W bulbs are on the edge of passing ANSI/UL standards, a critical condition for placing such sets in the marketplace. The 0.20 W bulbs, on the other hand, more safely allow the set to operate, however, either could be used.

While the 0.25 W bulbs (2.5V, 100 mA) were close in brightness to the 0.425 W bulbs (2.5V, 170 mA) that are commonly used, by using a thinner filament wire or other techniques to compensate for lumen output, the brightness of the 0.25 watt bulb is substantially equal to the standard 0.425 bulb. A conventionally constructed 0.20 W bulb (2.5V, 80 mA) bulb is even dimmer than the 0.35 W bulb (2.5V, 140 mA), and in the holiday market, the market demands bright bulbs.

To make up for the shortcomings of a conventionally constructed 0.20 W bulb, the bulbs of the present invention, noted generally at600inFIGS. 16 and 17, employ a higher purity tungsten filament, along with a tighter coil of the filament602. Further, the filament602is disposed higher into the bulb canopy608by the dimension H, noted inFIG. 15. The filament602is connected by relatively longer leads604than the leads504of the prior art that support the prior art filament502. An advantage of such disposition is that losses from the plastic bulb adaptor606at the bottom of the bulb600did not absorb as much light. Such disposition of the filament602provides for a measurably brighter bulb600, and also, as viewed by the human eye, an even brighter bulb600is perceived as compared with the prior art construction ofFIG. 15, as the filament602is higher up into the bulb canopy608, a construction that hasn't been done in the industry.

Further, to enhance the brilliance of the reduced wattage, one version of the low energy bulb600of the present invention, the filament602is formed of a purer form of tungsten and is of thinner construction as compared to the prior art bulb500. Additionally, the filament602is wound tighter than the filament502of the prior art. However, one skilled in the art would recognize that if brighter bulbs were not desired, standard bulb construction could be utilized.

In addition, as noted with respect toFIG. 2above, resistor sets10may be employed with light sources26being LEDs. Such LEDs typically operate at much lower current (20 mA) with a power draw of 0.08 W or less, and therefore allow for very cool operation of the resistor bypass circuit28, even when the bypass resistor28is continually conducting. In either case, there is substantial energy savings. In another embodiment, higher power LEDs or several LEDs in parallel may be employed across the bypass resistor.

The above noted features allow the resistor bypass circuit10to operate as a twinkling set by inserting a flasher bulb into any part of the circuit or, if provided, into a socket. Flasher bulbs are bulbs where a bimetallic strip heats, and open circuits the bulb (see for example, Fisherman), where a normal holiday light set that creates a twinkling effect has to use twinkling bulbs, where when the bimetallic strip is heated by the filament, it shorts out the bulb, allowing the remaining bulbs to light. In such sets where the bulbs short, ANSI/UL has very stringent requirements for construction and operation. In contrast however, in the resistor bypass set10of the present invention, use of a flasher bulb is not restricted, nor does it pose any additional safety concerns, as when the flasher bulb open circuits, it allows the resistor bypass set to work as it would normally, and actually reduces the current to the remaining bulbs, allowing the remaining bulbs to run cooler, as compared to the twinkle bulb set where it operates hotter when one or more bulbs is in the shorted condition.

The resistor bypass set10also has the advantage of being a safer set than the standard mini light sets that commonly use a shunt wire inside the bulb to allow the current to continue flowing, as sets containing shunted bulbs create short circuits across the bulb, further dividing the input voltage by the remaining bulbs, increasing the power drop across each bulb. The increased power drop increases the surface temperature of the bulb, and causing the remaining bulbs in the set to burn out faster. This repeated action causes the bulbs to become very hot, where as the resistor bypass set10of the present invention operates such that every bulb failure, places a higher resistance into the set than the bulb it replaces, causing the remaining bulbs to proportionally dim, causing them to increase their life, and to run cooler. However, the resistor could be sized such that the current is not reduced, and may remain relatively constant, or even slightly increase, depending on the effect desired.

FIG. 3is an embodiment of the present invention in the form of a series-connected decorative light string30. Decorative light string30includes power plug32, optional light source assemblies34, incandescent bulbs36and bypass resistors16. Power plug32may directly plug into utility power (120V, 208V, 220V, 240V, 280V, etc), connect to a step down power supply (such as a Class 2 power supply) or may be omitted for direct connection to a power source. As shown inFIG. 3, incandescent bulbs36may be a miniature bulb-type (mini bulb) operating on 2.5 VAC at 70-120 mA, or some other low current draw bulb. Resistors16may be in the range of 30 ohms to 60 ohms, though the value of resistors16will vary according to the total current flow desired, as well as according to other factors mentioned above. Resistors16are configured in parallel with light sources36. Light source assemblies34, if provided, are configured electrically in series with each other. As indicated earlier, when a light source assembly36fails, total system current will flow through the corresponding bypass resistor16, allowing the other light sources36to remain lit.

In one embodiment of the decorative light string30includes one or more light source assemblies34that includes a flashing device, but does not include a bypass element16in parallel, causing all of the remaining light source assemblies34in the series circuit of decorative light string30to flash.

Some methods of making light source assemblies34are further described inFIGS. 4a-d, but the present invention is not limited to the embodiments depicted in the figures.FIG. 4aillustrates a light source assembly34aincluding a light source36ain the form of a mini bulb, and a lamp holder35a.FIG. 4billustrates a light source assembly34bthat includes a light source assembly34b, a light source36bin the form of a mini bulb, a bypass resistor16, and a lamp holder35b. Lamp holder35bmay be larger than lamp holder35ato accommodate bypass resistor16. Bypass resistor16is connected across light source36bin parallel. The connection may be accomplished by soldering, crimping, friction fit, compression fit, or other means, including connecting to a pair of brass contacts (not shown), to the leads of light source26b, or to other conductors.

FIG. 4cillustrates yet another light source assembly, light source assembly34c, which includes a light source assembly34c, a light source36cin the form of a mini bulb, a bypass resistor16, and a lamp holder35c. In this embodiment, lamp holder34cis even larger than lamp holder35b.

FIG. 4dillustrates another light source assembly, light source assembly34d, which includes a light source assembly34d, a light source36din the form of a mini bulb, a bypass resistor16, and a lamp holder35d. In this embodiment, lamp holder34dmay be longer than lamp holder35b. In the embodiment shown inFIG. 4, one lead of bypass resistor16can be crimped to the brass contact. The other lead of bypass resistor16may be crimped to a second brass contact17, or connected by other means, such that it is electrically in parallel with light source36d. Other means includes being connected to the leads of light source36. In addition to crimping, soldering, friction fit, compression, and other common connection means may be employed.

In yet another embodiment, light sources36may be mini bulbs filled with an inert gas. Since the use of a bypass resistor16has the potential to decrease current flow through light sources36, an inert gas, such as Krypton, can be used in place of a vacuum to allow for the bulb filament to burn whiter and maintaining the same bulb life expected from mini bulbs and get even closer to a standard mini bulb brightness.

Lamp holders35of light source assemblies34may include molded lamp holders, assembled-on lamp holders, heat-shrink formed lamp holders, and other types of lamp holders. Light sources36may be removable, or non-replaceable. In another embodiments, the light source assemblies34may by mounted on a rigid or flexible printed circuit board, or connected directly to conductors or wires.

Another embodiment of the present invention is a light string40as shown inFIG. 5. Light string40includes an optional power plug42, light sources26, current-limiting resistors24, and bypass resistors28. Light sources26, current limiting resistors24, and bypass resistors28may be packaged together into light source assemblies44. The embodiment as shown works substantially as described above.

One embodiment of light source44is shown inFIG. 6. Lamp holder base33houses bypass resistor28, brass contacts17, and the ends of wires45. Bypass resistor28is connected to brass contacts17or other contact material to create a parallel configuration. Brass contacts17may be crimped on to wires45or other conductors. The optional lamp holder adapter48attaches to epoxy or some other material lens46. The lens46encases light source26, where light source26in this embodiment is an LED.

In another embodiment, the bypass resistor28, may be located directly across the LED leads49outside of any optional lens material,46.

In an alternate embodiment, the bypass resistor28may be located within the LED lens material46in parallel with the LED, or even inside the glass bulb envelope for incandescent bulbs.

FIG. 7illustrates another embodiment of the present invention, light string50, that utilizes partial rectification and blinking LEDs inside the epoxy lens. Light string50includes a power plug52, end connect53, and light source assemblies54and56. Light source assemblies54are connected in a series configuration. Light source assemblies56are connected to the series-connected light sources54as shown inFIG. 7.

Light source assemblies56includes a bypass resistor58, optional current limiting resistor60, light source62, which in this embodiment is an LED, and diode64. Light source assembly56may also includes a lamp holder (not shown), similar to the ones described above.

Light source assemblies54includes a bypass resistor58, optional current limiting resistor60, and light source62or light source66. In this embodiment, light source62is an LED chip, and light source66is a “blinking” LED that incorporates a chip that turns the LED on and off for a blinking or flashing effect. Operation of light source66is independent of the other light sources62due to the bypass resistor58. Light source assembly54may also includes a lamp holder (not shown), similar to the ones described above. Circuit50may utilize more than one blinking LED66, per circuit, or may only include blinking LED66as its light source.

In this embodiment, diodes64provide full-wave rectified power to light source assemblies54, causing light sources62and66of light source assemblies54to remain lit throughout most of the AC power cycle. Light source assemblies56receive partial rectification due to the particular configuration ofFIG. 7, causing light sources62of light source assemblies56to be powered throughout approximately half the AC power cycle.

When light source66is a blinking LED chip as shown inFIG. 7, current is periodically interrupted to the LED on the chip. Without bypass resistors58, this would cause all light sources in light string50to lose power due to an interruption of current flowing through the series-connected circuit. However, bypass resistor28allows current to continue flowing, maintaining power to other light sources62and66. Under normal operation, light source66will cause its LED to blink on and off, creating a twinkling effect, while other light sources62remain powered and lit. The use of multiple light sources66in a light string50creates a desirable twinkling effect as light sources66turn on and off, while light sources62remain lit.

In another embodiment, Light source66may be a multi LED chip configuration, programmed to change the light output color of the light source. Alternate embodiments may use a light source66where the bypass device80is an electronic circuit, or integrated circuit across the LED leads inside or outside of the epoxy housing/lens.

FIG. 8illustrates another embodiment where, a resistive bypass circuit70utilizes full-wave rectification to provide power to all light sources62and66. Resistive bypass circuit70includes an AC power source72, full-wave rectifier74with optional filter capacitor (not shown), main current limiting resistor78, bypass resistors80, light sources66and62. Full-wave rectifier74includes four diodes76. Full wave rectifier74may optionally employ one diode76, and a sufficiently sized filter capacitor to simulate full wave rectification. The AC power source72may be any source voltage.

In this embodiment, full-wave rectifier74provides DC power for bypass circuit70. Main current limiting resistor78limits the total amount of current flowing through circuit70and is sized partially based on the number of light sources62and66. The use of a single current limiting resistor78rather than multiple current limiting resistors simplifies design and manufacturing efforts, but may optionally be manufactured with multiple current limiting resistors as described in the embodiments above. Lights source66in the form of blinking LED chips, along with bypass resistors80create a twinkling effect when embodied in a light string. The size of bypass resistor80depends on the electrical characteristics of light source66, but in one embodiment may be 300 to 600 ohms. In some embodiments, bypass resistor80may only be used in conjunction with light sources66, and not with light sources60. This configuration would enable the twinkling effect, but would eliminate the bypass function at light sources62.

Another embodiment is the use of circuit70in a DC-supplied circuit, such that full wave rectifier74is not required. Additional embodiments of circuit70are configured in a series-parallel configuration. In another embodiment, light source66may be a multi LED chip configuration, programmed to change the light output color of the light source.

FIG. 9depicts a decorative lighting sculpture90that includes an optional power plug91, wires98, optional connectors96, main rod92, branches94, wires100and light source assemblies102. Power plug91may be connected in one embodiment to a 45 VDC to 50 VDC class 2 transformer with an output of 1.2 A, though other voltage ranges and power sources may be used. Alternatively, light sculpture90may not include power plug91and may be directly connected a power source. Light source assemblies102may be similar in configuration to the other light source assemblies described above, utilizing incandescent bulbs, LEDs, or other light sources configured in parallel with a bypass resistor.

In alternate embodiments, the bypass resistor may be replaced by bypass circuits utilizing transistors or other electronic active circuits.

The circuits and light strings of the present invention as applied to artificial trees, wreaths, garlands, and other artificial greenery, or alternatively to medium to large decorative products, such as stars, figures, icons and other decorative products provide a number of advantages. Replacing light strings due to light sources that have failed on a light string that is attached to an artificial tree or other decorative product, can be a difficult task since the string is not easily removed from the tree or products and the use of electric testers is not practical due to the fields such products produce with the volumes of wires and optional metal support structures. The bypass circuits and light sets described herein ensure that the light string will continue to remain lit even in the event of a light source failure, meaning that the entire light string does not have to be removed from the tree or decorative product. The combination of circuits, light strings and tree make a reliable, convenient lighted green goods system.FIGS. 10-12depict some of the artificial trees used in such a lighted green goods system.

FIG. 10shows one version of an artificial tree140that includes a tree trunk148, branches142, branch mains144, and sub-branches146. Artificial tree140may be constructed of a combination of many materials as described above. In this embodiment, artificial tree140is constructed primarily of painted metal, or in another embodiment made primarily of plastic, or a combination of plastic and metal.

FIG. 11shows another version of an artificial tree,140′. Artificial tree140′ includes tree trunk148′, branches142′, branch mains144′, sub-branches146′ and needles149. Needles149are commonly derived from PVC, nylon, and/or PE and may be green in color to make artificial tree140′ appear to be an evergreen or pine tree. In another embodiment it may use white needles and branches for different aesthetics.

FIG. 12light string, such as light string30,40,50,70, or a combination thereof, attached to branches142of tree140to form a pre-lit tree system200. Light strings30,40,50,70, or other embodiments of the present invention, may be similarly attached to trees140′. Light string30,40,50,70is shown attached to tree140via clips150. Clip150may include but are not limited to C clips, snap lock clips, and wire ties.

FIGS. 13 and 14depict the present invention in the form of flexible lighting, or rope lighting. Flexible lighting300as depicted inFIG. 13includes an outer encasement302, end cap304, power cap306, power cord308, power plug310, and one or more bypass circuits312. Flexible lighting300may operate on 120 VAC, which is transmitted through power plug310and power cord308, though other voltages may be used, and the input may be rectified or DC. Outer encasement302is typically made of a PVC material, and houses bypass circuit312. Power cap306assists in attaching power cord308to bypass circuit312and may attach to outer encasement302by any number of known methods.

Bypass circuits312are series circuits and each bypass circuit312is connected in parallel with the other. Bypass circuit312includes a plurality of light sources314electrically connected in parallel with bypass resistors320. Light sources318may be incandescent bulbs, LEDs, or other light sources. As described in previous embodiments, bypass resistor320may be replaced with another active circuit device. Bypass circuit312may also include conductors314and316which extend the length of flexible lighting300and provide power to the bypass circuits312when more than one circuit312is employed.

Operation of flexible lighting300is similar to those embodiments described above. During normal operation, current flows through both light source318and bypass resistors320. If light source318fails, the entire bypass circuit312current flows through bypass resistor320, allowing flexible lighting300to stay lit.

FIG. 14depicts a similar flexible lighting system that relies on LEDs, rather than incandescent bulbs. Flexible lighting400as depicted inFIG. 14includes an outer encasement402, end cap404, power cap406, power cord408, power plug410, and one or more bypass circuits412. Flexible lighting400may operate on 120 VAC, which is transmitted through power plug410and power cord408, though other voltages may be used, and the input may be rectified or DC. Outer encasement402is typically made of a PVC material, and houses bypass circuit412. Power cap406assists in attaching power cord408to bypass circuit412and may attach to outer encasement402by any number of known methods.

Bypass circuits412are series circuits and each bypass circuit412is connected in parallel with the other. Bypass circuit412includes a plurality of LEDs414electrically connected series with resistors419. Series connected LEDs414and resistors419are electrically in parallel with bypass resistors420. Light sources418may be LEDs, or other light sources. As described in previous embodiments, bypass resistor420may be replaced with another active circuit device. Bypass circuit412may also include conductors414and416which extend the length of flexible lighting400and provide power to the bypass circuits412when more than one circuit412is employed. The number or location of resistors419in each circuit421may vary based on circuit requirements, with some bypass circuits412not including a resistor419. In other embodiments, resistor419may be located external to circuit421, and in line with circuit Bypass circuit412.

Operation of flexible lighting400is similar to those embodiments described above. During normal operation, current flows through both light source418and bypass resistors420. If light source418fails, the entire bypass circuit412current flows through bypass resistor420, allowing flexible lighting400to remain lit.

Other embodiments of flexible lighting300and400may incorporate twinkling, flashing and color changing properties as previously described above.

It is desired to utilize incandescent bulbs with the embodiment ofFIG. 1. In order to make the resistive bypass set10function with modern, high temperature materials, it was needed to reduce the wattage of the bulbs to at least 0.25 W (standard bulbs in the industry are the 0.30 W bulb). It is preferable to use bulbs of 0.20 Watts. Sets using 0.25 W bulbs are on the edge of passing ANSI/UL standards, a critical condition for placing the resistive bypass set10in the marketplace. The 0.20 W bulbs, on the other hand, safely allows the set to operate and readily meet ANSI/UL standards, however, either 0.25 W or 0.20 W bulbs could be used.

In addition, the resistor sets with LED sources can also be employed, and as those typically operate at much lower current (20 mA) drawing approximately 0.08 W, those allow for very cool operation of the resistor bypass circuit. Additional embodiments may use a higher power LED or multiple LEDs connected in parallel across the resistive element.

Both of these lighting changes (lower wattage/higher brightness bulbs, and LEDs) were not anticipated, or contemplated by Fisherman, therefore only restricting it to flasher bulbs, and the use in such a set where the bulbs are never fully off.

In addition, this allows our resistor bypass set to operate as a twinkling set by inserting a flasher bulb into any circuit. Flasher bulbs are bulbs where the bimetallic strip heats, and open circuits the bulb, where a normal holiday light set that creates a twinkling effect has to use twinkling bulbs, where when the bimetallic strip is heated by the filament, it shorts out the bulb, allowing the remaining bulbs to light, however, in such sets where the bulbs short, ANSI/UL does not allow for such constructions in flexible (rope) lighting. However, in the resistor bypass set, use of a flasher bulb is not restricted, nor does it pose any additional safety concerns, as when the flasher bulb open circuits, it allows the resistor bypass set to work as it would normally, and actually reduces the current to the remaining bulbs, allowing to run cooler, vs. the twinkle bulb set where it operates hotter when one or more bulbs is in the shorted condition.

The resistor bypass set also has the advantage providing a shunting circuit, as ANSI/UL standards do not allow for shunts that short circuit the bulb in rope (flexible) lighting, as the bulbs are not replaceable, and shorts caused by shunt wires in or out to the bulb would create an unsafe condition as more and more bulbs burn out. A shunt wire inside the bulb to allow the current to continue flowing, as those bulbs create short circuits, further dividing the input voltage by the remaining bulbs, increasing the power drop across each bulb, thereby increasing the surface temperature of the bulb, and causing the subsequent bulb to burn out faster, and this repeated action causing the bulbs to become very hot, where as the resistor bypass set operates such that every bulb failure, places a higher resistance into the set than the bulb it replaces, causing the remaining bulbs to proportionally dim, causing them to increase their life, and run cooler. However, the resistor could be sized such that the current is not reduced, and may remain relatively constant.

In addition to decorative lighting, the bypass circuits of the present invention may also be used in general lighting applications including portable lighting, auto lighting, traffic lights and the like.

The invention addresses many of the deficiencies and drawbacks previously identified. The invention may be embodied in other specific forms without departing from the essential attributes thereof; therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive. The claims provided herein are to ensure adequacy of the present application for establishing foreign priority and for no other purpose.