Dual-color light strings

A dual-color light string comprising a first insulated electrical wire cord, a second insulated electrical wire, two light-emitting diode devices (LED devices) and transparent glue. The first insulated electrical wire is partially exposed to form a first soldering section. The second insulated electrical wire is partially exposed to form a second soldering section. The two LED devices are respectively electrically connected to the first soldering section and the second soldering section, and the directions of bias of the two LED devices from the first soldering section to the second soldering section are opposite to each other; The transparent glue covers the two LED devices, the first soldering section and the soldering section, extends to partially cover a first insulating layer of the first insulated electrical wire and a second insulating layer of the second insulated electrical wire.

FIELD OF THE INVENTION

The instant disclosure relates to decorative lighting, and in particular, to dual-color light strings.

BACKGROUND

A light string includes plural light sources directly soldered onto an electric cord at intervals, so as to form a string-shaped illumination device without traditional lamp holders as known in the art. The use and arrangement of small-sized light sources that include light-emitting diodes (LEDs) to form a light string is known.

In the art, light sources are soldered to a copper core after the insulating layer of the electric cord is removed, and then an electric-insulating treatment is performed on the solder joints. With this approach, light sources obviously stick out on the electric cord and typically are configured to have high-directivity. When a user arranges known light strings, which may include pulling on the light string, solder joints holding the light sources to the electric cord may crack or otherwise be compromised. Furthermore, as such, when an electric cord of the light string is pulled or bent, stress concentration often occurs at the solder joints, resulting in cracked solder joints.

Further, when dual-color lighting is desired, two light strings having different colors are often stranded or wound together. However, if two light strings are wound together, the problem of cracked solder joints is exacerbated.

SUMMARY

Accordingly, the instant disclosure provides a dual-color light string to solve the above-mentioned problems.

A dual-color light string according to the instant disclosure comprises a first insulated electric wire, a second insulated electrical wire, two light-emitting diode devices (LED devices) and transparent glue. The first insulated electrical wire includes a first conductive core, the first insulating layer covers the first conductive core, and the first conductive core is partially exposed to form a first soldering section. The second insulated electrical wire includes a second conductive core and a second insulating layer, the second insulating layer covers the second conductive core, the second conductive core is partially exposed to form a second soldering section, and the first conductive core and the second conductive core are electrically isolated from each other. The two LED devices are respectively electrically connected to the first soldering section and the second soldering section, and the directions of bias of the two LED devices from the first soldering section to the second soldering section are opposite to each other. Transparent glue covers the two LED devices, the first soldering section and the second soldering section and extends to partially cover the first insulating layer and the second insulating layer.

In one or more embodiments, the dual-color light string further comprises a carrier, the two LED devices are on the carrier, and the electrode connection nodes of the two LED devices are located at two lateral edge of the carrier to connect the first soldering section and the second soldering section.

In one or more embodiments, the two LED devices are combined into a single packaged chip.

In one or more embodiments, the carrier is perpendicular to the first soldering section and the second soldering section.

In one or more embodiments, the carrier includes two notches at the two lateral edges, the electrode connection nodes of the two LED devices connecting the first soldering section and the second soldering section are respectively located in the two notches, and the first soldering section and the second soldering section are respectively embedded into the two notches.

In one or more embodiments, the dual-color light string further comprises two carriers, and the two LED devices are respectively on the two carriers.

In one or more embodiments, the two carriers are perpendicular to the first soldering section and the second soldering section.

In one or more embodiments, the two LED devices are side-emitting LED devices and respectively emit light in a direction in parallel to the first insulated electrical wire and the second insulated electrical wire.

In one or more embodiments, the directions of light emitting of the two LED devices are the same or opposite of each other.

In one or more embodiments, the two carriers are in parallel to the first soldering section and the second soldering section.

The instant disclosure also provides a light string that comprises a first insulated electrical wire including a first conductive core and a first insulating layer; wherein the first insulating layer covers the first conductive core and the first conductive core is partially exposed to form a first soldering section; a second insulated electrical wire including a second conductive core and a second insulating layer; wherein the second insulating layer covers the second conductive core, the second conductive core is partially exposed to form a second soldering section, and the first conductive core and the second conductive core are electrically isolated from each other; an LED device electrically connected to the first soldering section and the second soldering section; wherein the LED device is a side-emitting LED device having a light emitting direction in parallel to the first insulated electrical wire and the second insulated electrical wire; and transparent glue covering the LED device, the first soldering section and the second soldering section and extending to partially cover the first insulating layer and the second insulating layer. In one embodiment, at least two LED devices are respectively soldered onto plural pairs of soldering sections, and the direction of bias of the these LED devices from the first soldering section to the second soldering section are opposite to each other, so as to form a dual-color light string.

In the dual-color light string according to one or more embodiments of the instant disclosure, the LED devices are firmly fixed between the first insulated electrical wire and the second insulated electrical wire to provide dual-color illumination.

DETAILED DESCRIPTION

Referring toFIGS. 1A, 1B and 2, a dual-color light string100according to a first embodiment comprises a first insulated electrical wire110, a second insulated electrical wire120, an LED assembly151, and a transparent covering, such as an adhesive or glue, “transparent glue”140. In an embodiment, dual-color light string100may also include a power plug (not depicted) for connecting light string100to an external power supply, and/or a power receptacle (not depicted), for connecting light string100to a power plug of another light string, such as a light string100.

In an embodiment, dual-color light string100may include a controller101for selectively controlling power transmitted to LED assemblies151.

In an embodiment, dual-color light string100may include a transformer or power converting circuitry103for converting an incoming alternating-current (AC) power to a direct-current (DC) power.

In an embodiment, LED assembly151includes a carrier150, and two LED devices130on carrier150, the two LED devices130comprising a “set” of LED devices130. Two LED devices130may include a first LED device130labeled as130a, and may include a second LED device130labeled as130b.

AlthoughFIGS. 1A and 2depict only one LED assembly151with two LED devices130as a set, it will be understood that the dual-color light string100according to the instant disclosure may equipped with a plurality of LED assemblies151with sets of LED devices130. These LED device130sets are continuously arranged on the first insulated electrical wire110and the second insulated electrical wire120, and are electrically connected to the first insulated electrical wire110and the second insulated electrical wire120in parallel, or as described further below, LED device130sets may be electrically connected to one another in parallel, series, or in a series-parallel arrangement.

Referring specifically toFIG. 1B, an electrical schematic of a plurality of LED assemblies151connected in parallel to each other to form a circuit of an embodiment of a light string100is depicted. In the depicted embodiment, each LED assembly151includes a set of LED devices130comprising two LED devices130. A first LED device130(labeled as LED device130a) is electrically connected to a second LED device130(labeled as LED device130b) in parallel. In the depicted embodiment, LED devices130aand130bare electrically connected in parallel, but are electrically connected to wires110and120to be electrically biased opposite one another, as described further below.

In operation, a voltage bias or polarity may be selectively controlled by controller101of light string100or by another control device so as to positively bias a first LED device130a, while negatively biasing a second LED device130b, such that first LED device130aemits light of a first color while second LED device130bdoes not emit light, or conversely, negatively bias the first LED device130a, while positively biasing the second LED device130b, such that the second LED device130bemits light of a second color, while the first LED device130adoes not emit light.

When a DC voltage is selectively applied to the sets of LED devices130, as described above, the controller101may, based on the input of a user, or based upon instructions stored in a memory device associated with the controller101, selectively control the power/voltage bias delivered to the LED sets. A first electrical bias configuration may cause the first LED device130ato emit light continuously for a predetermined period of time; a second bias configuration may cause the second LED device130bto emit light continuously for a predetermined period of time. The controller101may also selectively alternate the bias to cause the LED devices130aand130bto alternate being powered on and off. For example, the first LED device130amay be on and emit light of a first color for a few minutes (or another predetermined period of time), then turned off, with the second LED device130bbeing turned on to emit light having a second color. In other words, the light color is changed back and forth by changing the electrical bias to the set of LED devices130. It will be understood that any number of switching or alternating programs may be used to selectively control LED devices130and to create a lighting effect using one or more light colors.

Alternatively, controller101may provide an alternating current (AC) power to LED devices130. When an AC power is applied to the first insulated electrical wire110and the second insulated electrical wire120, the direction of the bias from the first insulated electrical wire110to the second insulated electrical wire120continuously changes, in every half-period, one of the two LED devices130is forward biased to emit light, and the other one is disabled as being reverse biased. By continuously applying the alternating current, the two LED devices having different colors emit light alternatively. At a relatively high frequency, such as 60 Hz, the LED devices alternate very quickly, and in such case, the human eye may perceive a third color that is a combination of the first color and the second color. In other instances, a user may perceive the two colors alternatingly as the bias is alternated.

As shown inFIG. 1AandFIG. 2, the first insulated electrical wire110includes a first conductive core112and a first insulating layer114. The first insulating layer114covers the first conductive core112, and the first conductive core112is partially exposed to form a first soldering section116.

The number of first soldering sections116on the first insulated electrical wire110is determined according to the number of the sets of the LED devices (and of LED assemblies151). In an embodiment, and as depicted inFIG. 1B, each LED assembly151includes a set of LED devices130that has two LED devices130. In other embodiments, a set may include three or more LED devices130. In an embodiment including three LED devices130, three colors of light may be emitted by the set of LED devices130, one color for each LED device130. In an embodiment each of the three colors are different from one another, as opposed to any two LED device emitting substantially the same color.

In an embodiment an LED device130comprises a single LED, emitting a single color.

In another embodiment, an LED device130includes multiple LEDs, such as a red-green-blue (RGB) LED, and a controller chip, such that the LED device130is capable of emitting a light color determined by control data, such as that stored in the controller chip or otherwise communicated to the controller chip, as would be understood by one of ordinary skill in the art.

The second insulated electrical wire120includes a second conductive core122and a second insulating layer124. The second insulating layer124covers the second conductive core122, the second conductive core122is partially exposed to form a second soldering section126, and the first conductive core112and the second conductive core124are electrically isolated from each other. In an embodiment, the first insulating layer114and the second insulating layer124are joined together by a portion of insulating material located between wires110and120. In an embodiment, insulating layers114and124are formed, such as by extrusion, over conductive cores112and114during the manufacturing process, causing wires110and120to be mechanically joined together at the insulating layers114and124. In an embodiment, wires110and120may be spaced apart and connected by a laterally-extending, as well as axially-extending, portion of insulation between the wires. Such a joining portion is described in further detail in U.S. pending application Ser. No. 16/298,935, entitled Dual-Color Light Emitting Diode Light Strings, which is incorporated herein by reference in its entirety.

The number of the second soldering sections124on the second insulated electrical wire120may be determined according to the number of LED assemblies151and the sets of the LED devices130, with one first soldering section116being paired with one second soldering section126.

In an embodiment, the first conductive core112and the second conductive core122comprise copper or copper alloy wires, with the metal or alloy having good ductility and conductivity. Cores112and122may also comprise primarily aluminum wires, rather than copper. Other conductive materials, including nickel, and other metals, may be used, as would be understood by one of ordinary skill.

In an embodiment, the first conductive core110, as well as the second conductive core120, may comprise a single conductor strand, as depicted in the figures. In other embodiments, the conductive cores may comprise multiple strands of conductors which in an embodiment, are twisted together.

In an embodiment, the first insulating layer114and the second insulating layer124are made of plastic. The first second insulating layer114and the second insulating layer124can be separated from each other or combined into one piece. In some embodiments, the first insulating layer114and the second insulating layer124are insulating coating, such as an enamel coated, for example, such that first insulated electrical wire110and the second insulated electrical wire120comprise enameled “magnet wires”.

As shown inFIG. 1AandFIG. 2, the two LED devices130are respectively electrically connected to the first soldering section116and the second soldering section126. In an embodiment, the direction of electrical bias of the two LED devices130from the first soldering section116to the second soldering section126are opposite to each other, as depicted inFIG. 1B.

In an embodiment, the two LED devices130, LED device130aand LED device130b, are LED devices having different colors, for example, one LED device130acomprising a blue LED device and the other LED device130bcomprising a red LED device; the red LED device being oppositely biased as compared to the blued LED device. In other words, when a bias voltage is applied to the first insulated electrical wire110and the second insulated electrical wire120, only one of the two LED devices emits light while the other is disabled. In an embodiment, this opposite biasing arrangement is accomplished by electrically connecting the two LED devices130in parallel, with an anode from a first LED device130aconnected to the cathode of the other, or second, LED device130b, with that anode and cathode being connected to one of wires110or120. A cathode from the first LED device130ais electrically connected to the anode of the second LED device130b, and that anode and cathode are electrically connected to the other of the two wires110or120. As such, the first and second LED devices130are connected in parallel to one another and oppositely electrically biased.

In an embodiment, and as depicted inFIG. 2, the transparent glue140covers the two LED devices130, the first soldering section116and the soldering section126and extends to partially cover the first insulating layer114and the second insulating layer124. In an embodiment, and as depicted, the transparent glue140has a largest cross-section located corresponding to the two LED devices130, and the cross-section of the transparent glue140shrinks gradually along directions toward the first insulating layer114and the second insulating layer124. That is, the transparent glue140not only covers the two LED devices130, the first soldering section116and the soldering section126, but also covers the parts of the first insulating layer114and the second insulating layer124adjacent the first soldering section116and the second soldering section126.

In other embodiments, glue140does not cover portions of insulating layers114and124; in one embodiment, glue140abuts insulating layers114and124.

The material of the transparent glue140can be a rapid solidification glue such as a UV-cure adhesive. In an embodiment, liquid glue is dispensed onto the two LED devices130by a glue dispenser, the liquid glue flows to the first insulating layer114and the second insulating layer124, and then the liquid glue is cured by directing UV light to the glue to solidify it.

The transparent glue140is used to protect the two LED devices130, the first soldering section116and the second soldering section126, and also serves as optical component for light diffusion.

Still referring toFIG. 1andFIG. 2, in an embodiment, the dual-color light string100according to the first embodiment further includes a carrier150. In the embodiment depicted, the two LED devices130are attached to single carrier150. The two LED devices130may be combined into a single packaged chip, and disposed on one side of the carrier150. Alternatively, the two LED devices130are provided as two separate LED chips, and respectively disposed adjacent one another on one side of the carrier150. In these embodiments, light from LED devices130is transmitted axially, at least partially, in a direction generally parallel to a longitudinal or lengthwise axis of wires110and120.

Alternatively, and not depicted, one LED chip is on one side of carrier150(front side), and the other is on another side of carrier150(back side), such that some light may be directed in opposite axial directions.

The electrode connection nodes132of the two LED devices130for connecting to the first soldering section116and the second soldering section126are located at two lateral edges, a first edge and a second edge, of the carrier150. For firmly fixing the carrier150, the carrier150is perpendicular to the first soldering section116and the second soldering section126, such that a front side of the carrier, the one onto which the LED devices130are mounted, are directed toward the insulating layers114and124and parallel to lengthwise axes formed by each of the two wires110and120. The carrier150includes two notches152at the two lateral edges, and the electrode connection nodes132of the two LED devices130for connecting the first soldering section116and the second soldering section126are respectively located in the notches152. The first soldering section116and the second soldering section126are respectively inserted or embedded into the two notches152, so as to initially fix the carrier150and connect the electrode connection nodes132to first soldering section116and second soldering section126. In the first embodiment, two ends of the LED devices130share two electrode connection nodes132. In one such embodiment, an anode of one LED device130and a cathode of the other LED device130share a common node132.

In an embodiment, and as depicted notches152are defined by an arcuate surface of a node132. In an embodiment, the notch152defines an arc radius that is approximately the same as the radius of a conductor core112or122so as to maximize contact between the node132and the soldering section of the conductor core. In an embodiment, node132defines a half circle (180° arc) and receives a portion of a soldering section116or126of conductor112or122, respectively, that comprises approximately half of the circumference of the conductor core. In one such embodiment, lateral forces between wire110and120, assist in holding the carrier150in position between the two wires.

In an alternate embodiment, notch152defines an arc that is slightly larger than 180°, such that notch152contacts more than half the circumference of the conductor. In such an embodiment, a soldering section116or126is forced into notch152, creating an interference fit, or even a snap fit, thereby further assisting in holding carrier150in position between wires110and120.

As depicted inFIG. 3andFIG. 4, a dual-color light string100according to a second embodiment comprises a first insulated electrical wire110, a second insulated electrical wire120, two LED assemblies151, each with a carrier150and an LED device130, and transparent glue140.

The dual-color light string100according to the second embodiment includes two carriers150, and the two LED devices130are mounted on the two carriers150, one on each carrier. The two carriers150are positioned perpendicular to the first soldering section116and the second soldering section126, and each of the two carriers150includes two notches152at the two lateral edges. The first soldering section116and the second soldering section126are respectively embedded into the two notches152.

In this second embodiment, and as depicted inFIG. 4, the two LED devices130are on same side of the two carriers150, such that both LED devices130face the same direction. In one such embodiment, the light from one LED is transmitted toward a back side of an adjacent carrier150, thereby reflecting some light off of the adjacent carrier150, while the other LED device130on the other carrier150transmits or directs light toward adjacent insulating layers114and124, as well as portions of soldering sections116and126.

In an alternate second embodiment, as depicted inFIG. 4, the two LED devices130face in opposite directions. In one such embodiment, light from one LED device130directs light toward adjacent insulating layers114and124, as well as adjacent portions of soldering sections116and126. Light from the other LED device130is directed in an opposite direction, toward adjacent insulating layers114and124, as well as adjacent portions of soldering sections116and126. In this alternate second embodiment, a different lighting effect is achieved as light is directed and reflected in a different manner as compared to those lighting effects achieved by the embodiments ofFIGS. 1 and 2orFIG. 3.

In an embodiment, the LED devices130of light string100ofFIGS. 3 and 4are electrically configured to form the circuit depicted inFIG. 1B, even though the LED devices130are disposed on separate carriers150.

Referring toFIG. 5andFIG. 6, a dual-color light string100according to a third embodiment comprises a first insulated electrical wire110, a second insulated electrical wire120, two LED assemblies151each with an LED device130carrier150, and transparent glue140.

In the depicted embodiment, the soldering pads are disposed on the side of the carrier150and are soldered onto the first soldering section116and the second soldering section126, while the LED top surfaces131are perpendicular to wires110and120.

Alternatively, rather than disposing the carrier150on its side, such that a bottom surface of each carrier150is perpendicular to the first insulated electrical wire110and the second insulated electrical wire120, the carrier150may alternatively be disposed on its bottom and in parallel to the first insulated electrical wire110and the electric wire120, so as to increase the soldering area on the first soldering section116and the second soldering section126. See also,FIG. 7which depicts carriers150arranged such that the bottom surfaces of the carriers150and associated soldering pads are in contact with sections116and126. However, unlike the LED devices ofFIG. 7, in an embodiment, rather than emit light from a top surface131, LED devices emit light from a side of the LED devices, so as to direct light parallel to wires110and120.

In the embodiments ofFIGS. 5 and 6, the directions of light emission are in parallel to the first insulated electrical wire110and the second insulated electrical wire120, and the directions of light emitting of the two LED devices130are the same (FIG. 5) or opposite (FIG. 6) to each other.

Referring toFIG. 7, a dual-color light string100according to a fourth embodiment comprises a first insulated electrical wire110, a second insulated electrical wire120, two LED assemblies151each with an LED device130and a carrier150, and transparent glue140.

In an embodiment, the carrier150in the fourth embodiment may not include the side notches152; the two carriers150are disposed with soldering pads on the bottom surfaces on the first soldering section116and the second soldering section126, such that LED devices130face in a direction transverse to the axes of wires110and120, which may be considered an “upward” direction. The bottom side of the two carriers150are directly soldered to the first soldering section116and the second soldering section126. The two LED devices130as depicted emit light upward (top/front-emit) from a top surface131, as exemplified and indicated by the solid-line arrows, but alternatively, LED devices130may be side-emitting LED devices that emit light transverse to a top surface131, as exemplified and indicated by the broken-line arrows. In other words, the carriers150in the third embodiment can be placed horizontally and the LED devices130are arranged to emit light laterally (including being parallel to wires110and120).

Referring toFIGS. 8A and 8B, a circuit2for the dual-color light string is shown according to an embodiment, for arranging the dual-color light string100as shown in the first to fourth embodiments into a long light string with serial and parallel circuit loops.

As shown inFIG. 8, the circuit2comprises a first insulated electrical wire110, a second insulated electrical wire120, a third insulated electrical wire160and a plurality of pairs of LED devices130.

As shown inFIG. 8, circuit2of the light string is configured to receive power at wires110and160. In an embodiment, the first insulated electrical wire110is configured to receive a first voltage, and the third electric wire160configured to a second voltage. In an embodiment, circuit2may be configured to receive direct current (DC) power.

In one such DC embodiment, the first voltage may be greater than the second voltage such that a positive voltage potential is applied from wire110to wire160. InFIG. 8, this is depicted as wire110having a “+” or positive voltage, while wire160is depicted as having a “−” or negative voltage. In such an embodiment, the second voltage may be ground, or may simply be a voltage that is less than the first voltage so as to cause a positive voltage potential from wire110to wire160. As described further below, a positive voltage potential from wire110to wire160will present a positive or forward electrical bias across first LED device130aand cause a first LED device130ato emit light of a first color.

In another DC embodiment, the second voltage may be greater than the first voltage such that a positive voltage potential is applied from wire160to wire110(or a “negative” voltage potential is applied from wire110to wire160). InFIG. 8, this is depicted as wire110having a “−” or negative voltage, while wire110is depicted as having a “+” or positive voltage. In such an embodiment, the first voltage may be ground, or may simply be a voltage that is less than the second voltage so as to cause a positive voltage potential from wire160to wire110. As described further below, a positive voltage potential from wire1600to wire110will present a forward bias across second LED device130band cause second LED device130bto emit light of a second color.

The second insulated electrical wire120is used as a connection node between the sets of LED devices130. In practice, any two of the first insulated electrical wire110, the second insulated electrical wire120and the third electric wire160in the this circuit embodiment are used to be the first insulated electrical wire110and the second insulated electrical wire120in the first to fourth embodiments.

As depicted inFIGS. 8A and 8B, the LED assemblies151and the plurality of pairs of LED devices130are categorized into two groups. In the first group “A”, each one of the pair of the LED devices130ais connected in parallel to the other, each pair of LED devices130is connected in parallel to the others, and the first insulated electrical wire110and the second insulated electrical wire120serve as the two connecting nodes of the parallel LED devices130(similar to those embodiments described above). In the second group “B”, each LED assembly151with each pair of LED devices130bis connected in parallel to the other, each pair of LED devices130bis connected in parallel to the others, and the second insulated electrical wire120and the third electric wire160serve as the two connecting nodes of the parallel LED devices130. Furthermore, the second insulated electrical wire120is the connecting node between the first group A of LED devices130and the second group B of the LED devices130, such that the first group A is serially connected to the second group B.

Still referring toFIGS. 8A and 8B, in an embodiment, and as depicted, the circuit2in a fifth embodiment further comprises an optional current-limiting resistor180, electrically connecting the first insulated electrical wire110to an external source of power; the resistor180for limiting current in the first insulated electrical wire110. The current-limiting resistor180limits the current in the first insulated electrical wire110, so as to prevent the LED devices130from being damaged by over-current.

In the embodiment depicted, the first insulated electrical wire110, the second insulated electrical wire120and the third electric wire160are arranged in parallel, such that the insulating layers of the first insulated electrical wire110, the second insulated electrical wire120and the third electric wire160can be combined together into a single piece. Consequently, only portions of the wires at the soldering sections need to be separated during manufacture of the light string100so as to attach the LED devices130. By such an approach, the circuit2becomes a long single piece light string for convenient wiring arrangement.

Referring toFIGS. 9A and 9B, another embodiment of a circuit3of the light string comprises a first insulated electrical wire110, a second insulated electrical wire120, a third electric wire160and a plurality of LED assemblies151, each assembly151having a pair of LED devices130(130aand130b). The circuit3further comprises a third cut-off point C3indicated with an “X” in the figures, a second cut-off point C2indicated with another “X” and a first cut-off point C1indicated with another “X”, to form the circuit loop in the this embodiment. A cut-off point refers to a point in the wire where the conductor is “broken,” such that the wire is discontinuous at the cut-off point. A cut-off point may be accomplished during manufacture by punching out, or otherwise removing, a small section of insulated wire or conductor. A cut-off point may also be accomplished by cutting or breaking the wire without removing a portion of the wire.

Any two of the first insulated electrical wire110, the second insulated electrical wire120and the third electric wire160in this circuit embodiment can be used to be the first insulated electrical wire110and the second insulated electrical wire120in the first to fourth embodiments of light strings100described above.

Referring toFIGS. 9A and 9B, the first insulated electrical wire110, the second insulated electrical wire120and the third electric wire160are arranged in parallel along an axially-extending direction L. In an embodiment, the three electrical wires are single metal wires or stranded conductors combined together by a one piece insulating layer. The third cut-off point C3, the second cut-off point C2and the first cut-off point C1are arranged sequentially along the extending direction L and respectively “cutting off” the third electric wire160, the second insulated electrical wire120and the first insulated electrical wire110, so as to divide the circuit3into plural sections according to the third cut-off point C3, the second cut-off point C2and the first cut-off point C1. As described above, the term “cutting off” means cutting or breaking or otherwise interrupting the conductor core so as to cause an electrical discontinuity in the conductor core and wire.

The plurality of pairs of LED devices130(each “pair” having two LED devices130electrically connected to each other in parallel) are categorized into groups, each group having a plurality of pairs of LED devices130, each of the plurality of pairs of LED devices130electrically connected to one another in parallel. The first group “A” of the LED devices130is arranged before the first cut-off point C1along the extending direction L, and connected to the first insulated electrical wire110and the second insulated electrical wire120.

The second group of the LED devices130, Group B, are arranged between the third cut-off point C3and the second cut-off point C2along the extending direction L, and connecting to the second insulated electrical wire120and the third electric wire160.

The third group of the LED devices130, Group C, are arranged after the second cut-off point C2along the extending direction L, and connecting to the second insulated electrical wire120and the third electric wire160.

Referring toFIG. 9, The fourth group or the rest of the LED devices130, Group D, are arranged after the first cut-off point C1and the second cut-off point C2along the extending direction Land connected to the first insulated electrical wire110and the second insulated electrical wire120.

By such an approach, the LED devices130are sorted into four groups, Groups A, B, C and D. Each of the first group, Group A, of the LED devices130is connected in parallel, and the first insulated electrical wire110and the second insulated electrical wire120serve as the two connecting nodes of the parallel LED devices130. The second LED devices130, Group B, are connected in parallel, and the second insulated electrical wire120and the third electric wire160serve as the two connecting nodes of the parallel LED devices130. Meanwhile, the second insulated electrical wire120is the connecting node between Group A of LED devices130and Group B of the LED devices130, such that the Group A is serially connected to Group B.

The third LED devices130, Group C, are connected in parallel, and the second insulated electrical wire120and the third electric wire160serve as the two connecting nodes of the parallel LED devices130. The second insulated electrical wire120between the second group and the third group is cut off by the second cut-off point C2, such that the third group of LED devices130, Group C, is serially connected to the second group of LED devices130, Group B. Similarly, the fourth group of the LED devices130, Group D, is connected in parallel, and the first insulated electrical wire110and the second insulated electrical wire120serve as the two connecting nodes of the parallel LED devices130, and the first insulated electrical wire120between the first group and the fourth group is cut off by the first cut-off point C1, such that the fourth group of LED devices130, Group D, is serially connected to the third group of LED devices130, Group C.

In an embodiment, the first electric wire110is used to transmit power from a power source, such as from controller101to the LED devices130. As described above, power may be selectively transmitted such that on LED device130of a set of LED devices130of an LED assembly151, such as an LED device130a, is powered, while the other LED device130, such as LED device130b, is not powered, due to opposite biasing of the LED devices130of the set. In an embodiment, a DC voltage is selectively transmitted so as to switch polarity or biasing; in an alternative embodiment, AC power may be applied, as discussed above with respect to the other embodiments. In the embodiments ofFIGS. 9A and 9B, power is applied at one end of wire110adjacent Group A, and at another end of wire110adjacent Group D, as depicted.

In an embodiment, the first insulated electrical wire110, the second insulated electrical wire120and the third electric wire160are arranged in parallel, the circuit3becomes a long single piece light string for convenience of cords arrangement.

In an embodiment, the circuit3may include a current-limiting resistor180, electrically connecting the first insulated electrical wire110to the source of power for limiting current in the first insulated electrical wire110. The current-limiting resistor180limits the e current the first insulated electrical wire110, so as to prevent the LED devices130from being damaged by over-current.

Referring toFIG. 10, a light string100according to a seventh embodiment comprises a first insulated electrical wire110, a second insulated electrical wire120, an LED device130, a carrier150and a transparent glue140.

Referring toFIG. 10, the first insulated electrical wire110includes a first conductive core112and a first insulating layer114. The first insulating layer114covers the first conductive core112and the first conductive core112is partially exposed to form a first soldering section116. The second insulated electrical wire120includes a second conductive core122and a second insulating layer124. The second insulating layer124covers the second conductive core122, the second conductive core122is partially exposed to form a second soldering section126, and the first conductive core112and the second conductive core122are electrically isolated from each other.

Referring toFIG. 10, the carrier150is fixed on the first conductive core112and the second conductive core122, and the LED device130is disposed on a lateral side of the carrier150. The electrode connection nodes132of the LED device130for connecting the first soldering section116and the second soldering section126are located at two lateral edges of the carrier150. By soldering the electrode connection nodes132onto the first soldering section116and the second soldering section126, the carrier150is fixed on the first soldering section116and the second soldering section126.

The LED device130is electrically connected to the first soldering section116and the second soldering section126via the electrode connection nodes132. The LED device is a side-emitting LED device having a light emitting direction in parallel to the first insulated electrical wire110and the second insulated electrical wire120. The transparent glue140covers the LED device130, the first soldering section116and the second soldering section126and extending to partially cover the first insulating layer114and the second insulating layer124. In one embodiment, at least two LED devices130are respectively soldered onto plural pairs of soldering sections124and126, and the direction of bias of the these LED devices130from the first soldering section116to the second soldering section126are opposite to each other, so as to form a dual-color light string.

In the dual-color light string according to one or more embodiments of the instant disclosure, the LED devices130are firmly fixed between the first insulated electrical wire110and the second insulated electrical wire120to provide dual-color illumination. \

In an embodiment, one or more light strings100may be applied to a multi-section artificial tree, such that embodiments of the disclosure include artificial trees with light strings100. In one such embodiment, the number of light strings, and the number of lights may depend on the height and girth of the tree, with taller and/or larger trees having more light strings and more lights.

In an embodiment, one light string100is connected to a single branch of the tree. In another embodiment, one light string100is connected to multiple branches of the tree. In an embodiment wherein the artificial tree has multiple tree sections or portions, such as a lower, upper and middle tree portion, such as a tree described in U.S. Pat. No. 8,454,186, Modular Lighted Tree (incorporated herein by reference in its entirety), each tree section may include a single light string100, rather than multiple light strings100. In an alternate embodiment, each tree section includes multiple light strings100, but only one light string100is used for all branches at a common height along the trunk of the tree.