Patent Grant
9557044
The present invention relates to an LED lamp with dual mode operation from a fluorescent lamp fixture wired to supply either mains power or power from an electronic ballast associated with the fixture.
One conventional, elongated LED lamp can be retrofit into an existing fluorescent lamp fixture whose wiring is reconfigured so as to directly supply mains power to the LED lamp. With such an LED “retrofit” lamp, power is typically supplied to the lamp from a pair of power pins on one end of the lamp, with the pair of connector pins at the other end of the lamp not powering the lamp but providing mechanical support for the lamp. The foregoing arrangement for powering the lamp from the power pins at one end of the lamp has the benefit of limiting exposure to potentially life-threatening electrical shock from the mains current to a lamp installer during lamp installation.
A second conventional, elongated LED lamp can be retrofit into an existing fluorescent lamp fixture so as to use a fluorescent lamp electronic ballast contained in the fixture without reconfiguring the fixture wiring. As is the case with fluorescent lamps, the LED retrofit lamp obtains power from power pins at both (i.e., opposite) ends of the lamp. A representative LED retrofit lamp of this type is disclosed in U.S. Pat. No. 8,089,213 B2 to Park. The Park LED lamp has a single mode of operation from an existing fluorescent lamp ballast associated with a fluorescent lamp fixture. Park teaches the use of capacitors C11-C14 in his FIG. 1 to “control the capacitance of a series resonant circuit of a fluorescent lamp ballast” at Col. 4, II. 26-30. Inasmuch as Park teaches fluorescent lamp ballasts having a high frequency of 50 kHz (Col. 8, I. 58 & Col. 11, I. 4), capacitors C11-C14, of necessity, have a high impedance at typical mains frequencies of 50 or 60 Hz. Accordingly, capacitors C11-C14 provide the benefit of sufficiently attenuating any current at typical mains frequencies so as to prevent a potentially life-threatening electrical shock hazard if the LED retrofit lamp is accidentally placed into a fluorescent lamp ballast wired directly to power mains.
Lamp designers have recognized that it would be desirable to have an LED retrofit lamp with dual mode operation from either an existing fluorescent lamp ballast associated with a fluorescent lamp fixture, or directly from power mains. U.S. Pat. No. 8,575,856 B2 to Chung et al. provides an LED lamp with dual mode operation. However, a single, master circuit is used to power LEDs in the lamp whether the power is supplied by AC mains or whether the power is supplied by an existing fluorescent lamp electronic ballast. This attempt suffers in potential performance regarding energy efficiency and stability compared to an LED lamp that operates only from AC mains power, or an LED lamp that operates only from power supplied by a fluorescent lamp electronic ballast.
The Chung et al. LED lamp is also flawed in that it fails to mitigate a potentially life-threatening electrical shock hazard when a lamp is placed into a fixture that is wired directly to power mains. This is because, in the case of AC mains operation, power is applied across the LED lamp through the same circuit used when the fluorescent lamp electronic ballast is present. As a result, a potential shock hazard is created, which may be life-threatening to a lamp installer during lamp installation.
It would, therefore, be desirable to provide an LED retrofit lamp with dual mode operation from an existing fluorescent lamp electronic ballast associated with a fluorescent lamp fixture, as well as, alternatively, directly from power mains in an efficient and stable manner. It would also be desirable to provide such as lamp that can be configured to avoid a potential life-threatening electrical shock hazard when such a lamp is placed into a fixture wired to supply power directly from power mains.
The present invention combines dual modes of operation of an LED retrofit lamp. In a first mode, the LED retrofit lamp receives power from power mains in a fluorescent lamp fixture; in an alternative, second mode, the LED retrofit lamp receives power from a fluorescent lamp electronic ballast in a fluorescent lamp fixture. In the first mode, the LED lamp can be wired to receive power from a pair of power pins at one end of the lamp. In the second mode, the LED lamp receives power from a fluorescent lamp electronic ballast associated with the lamp fixture. The foregoing dual mode operation is accomplished through the use of first and second circuits respectively dedicated to the first and second modes of operation. While the first and second circuits share one common power pin on the LED lamp and typically power the same LEDs, the first and second circuits may be electrically isolated from each other via novel conduction control arrangements.
In one form, the present invention provides an LED lamp with dual mode operation for insertion into a fluorescent lamp fixture. The lamp fixture is wired to supply to the LED lamp either mains power or power from an electronic ballast supplying AC power at a ballast frequency. The LED lamp comprises an elongated housing having first and second ends. The first end of the elongated housing is provided with first and second power pins. The second end of the elongated housing is provided with a third power pin. A first circuit is intended to provide power to at least one LED contained within the elongated housing. The foregoing at least one LED is adapted to be powered in a first mode from power mains and to provide external light along a length of the elongated housing. The first mode occurs when the LED lamp is inserted into a fluorescent lamp fixture having power contacts that receive the first and second power pins and that are directly connected to the power mains supplying power at a mains frequency much lower than the ballast frequency. The first circuit limits current to the at least one LED adapted to be powered in a first mode. A second circuit is intended to provide primary power to at least one LED adapted to be powered in a second mode from the electronic ballast and to provide external light along a length of the elongated housing. The second mode occurs when the LED lamp is inserted into a fluorescent lamp fixture having power contacts that receive the second and third power pins, at opposite lamp ends, and that are connected to the electronic ballast for receiving power therefrom. The second circuit includes a rectifier circuit adapted to receive power from the second and third power pins. A first conduction control means serially connected between the second power pin and the rectifier circuit is adapted to permit the second circuit to power the at least one LED adapted to be powered in the second mode when the second and third power pins, at opposite lamp ends, are connected to the electronic ballast. A second conduction control means serially connected between the third power pin and the rectifier circuit is adapted to permit the second circuit to power the at least one LED adapted to be powered in the second mode when the second and third power pins, at opposite lamp ends, are connected to the electronic ballast.
In some embodiments, the at least one LED for being powered in a first mode and the at least one LED for being powered in a second mode have at least one LED in common. In other embodiments, the at least one LED for being powered in a first mode and the at least one LED for being powered in a second mode do not have any LEDs in common.
The foregoing LED lamp can be retrofit into an existing fluorescent lamp fixture and has dual mode operation either from an existing fluorescent lamp electronic ballast associated with the lamp fixture, or, alternatively, directly from power mains. Beneficially, the LED lamp can be configured to mitigate a potentially life-threatening electrical shock hazard when such a lamp is placed into a fixture wired to supply power directly from power mains. Some embodiments of the inventive lamp are configured to provide additional protection against shock exposure to a lamp installer.
Further, the foregoing LED lamp is more efficient to operate than using, as various prior art references teach, a single master circuit that senses whether a lamp fixture supplies power from an electronic ballast or directly from power mains, and that provides appropriate power to LEDs. Rather than using such a master circuit, as the foregoing summary of the invention teaches, the present invention uses first and second circuits to receive either mains power or power from an existing fluorescent lamp ballast. This approach eliminates the energy loss that results when using an active LED driver in a master circuit to reprocess power from an existing fluorescent lamp ballast. This approach also typically allows the second circuit to be formed inexpensively from a few passive components, such as a diode rectifier circuit and one or more capacitors.
Further features and advantages of the invention will become apparent from reading the following detailed description in conjunction with the following drawings, in which like reference numbers refer to like parts:
The examples and drawings provided in the detailed description are merely examples, and should not be used to limit the scope of the claims in any claim construction or interpretation.
In this specification and appended claims, the following definitions apply:
An “active component” connotes a controllable electrical component that supplies controllable energy in the form of voltage or current to a circuit containing the active component. Examples of active components are transistors.
An “active circuit” connotes a circuit using a control loop that incorporates feedback and an active element for the purpose of limiting current to a load.
A “passive component” connotes an electrical component that is incapable of supplying externally controllable energy in the form of voltage or current into a circuit containing the passive component. Examples of passive components are rectification diodes, LED diodes, resistors, capacitors, inductors, or magnetic ballasts operating at 50 or 60 Hz.
A “passive circuit” connotes a circuit that does not include an active component as defined herein.
An “electronic ballast for a fluorescent lamp” or the like connotes an instant start ballast, a rapid start ballast, a programmed start ballast, and other ballasts that use switch-mode power supplies to realize current-limiting for fluorescent lamps. An “electronic ballast for a fluorescent lamp ballast” does not include a so-called magnetic ballast.
“Power mains” connote the conductors through which AC or DC electrical power is supplied to end users. AC power is typically supplied at a frequency between about 50 and 60 Hz, and typically between about 100 and 344 volts RMS. Specialized power mains provide power at 400 Hz. A frequency of zero for power mains corresponds herein to DC power.
An “isolation” transformer, as that term is used herein, is not restricted to having a winding turns ratio of 1:1.
Other definitions are provided in the following description for “conduction control means” and the word “permit,” by way of example.
Power source 109 may be an AC source with a typical power mains frequency of 50 or 60 Hz or 400 Hz. Power source 109 may also be a DC power source, in which case the mains frequency is considered zero.
Referring again to
It should be noted that the same LED lamp 102 is described with a first mode of operating when directly wired to power mains in
Electrolytic capacitor 324, shown in second circuit 140, may be shared by first circuit 110. Alternatively, if an optional blocking diode 325 is connected between node 308 and electrolytic capacitor 324, first circuit 110 will not be required to charge such capacitor when first circuit 110 powers LEDs 300. The present inventors have discovered that, in some embodiments, first circuit 110 will not adequately charge electrolytic capacitor 324 of relatively large capacitance, and some flickering of LEDs 300 results. Blocking diode 325 can be formed from a p-n diode or another device that provides for unidirectional current flow, such as a Schottky diode or Silicon Controller Rectifier (SCR). The description for blocking diode 325 appearing in other drawings herein (e.g.,
When LEDs 300 are powered by first circuit 110 (
On the other hand, when LEDs 300 in LED circuit 303 of
Operation of second circuit 140 at elevated voltages reduces the current levels in second circuit 140; such reduced current levels reduce a potentially life-threatening electrical shock hazard from a person exposed to current from second circuit 140. Accordingly, in the U.S., for instance, it thus possible to meet the UL electrical shock hazard test described in UL 1598c standard and referenced UL 935 standard for the fluorescent lamp electronic ballast 122 (
Operation of second circuit 140 at elevated voltages, especially when being powered from a fluorescent lamp electronic ballast 122 (
The following will be a matter of routine skill to persons of ordinary skill in the art from the foregoing description of
In LED circuit unit 326 of
When second circuit 140 (
Operation of LED circuit unit 327 in LED circuit 304 of
The present inventors have discovered that when second circuit 140 powers LEDs 300 with considerably more voltage than first circuit 110, operation of second circuit 140 can cause various adverse effects. Such adverse effects include imposition on components of first circuit 110 of excessively high voltage that may exceed the voltage ratings of components of first circuit 110. Such adverse effects can cause a deleterious level of reverse leakage current through one or more steering diodes 314-321 and 328-335 in LED circuit 304 of
Preferred means to isolate first circuit 110 from unipolar current coming from second circuit 140, via LEDs 300, are either or both: (a) an interface field effect transistor (hereinafter, “FET”) 337 of the n-channel type in first conductor 339 in series with first conductor 339, between node 306 and LED circuit unit 326, and (b) an interface FET 342 of the p-channel type in series with second conductor 344, between node 310 and LED circuit unit 326. FETs 337 and 342 are referred to as “interface” FETs because they interface between first circuit 110 and LEDs 300. Interface FETs 337 and 342 are respectively biased by bias circuits 340 and 345 to cause conduction through these FETs at dc or approximately dc frequency when the voltage across nodes 306 and 310 reaches an intended voltage for powering LEDs 300, and to otherwise maintain non-conduction at dc or approximately dc frequency through these FETs. In the example mentioned above for LEDs 300 of
FETs 337 and 342 typically have body diodes that allow current at all frequencies to pass in one direction. Such body diodes for FETs 337 and 342 are shown as diodes 338 and 343, respectively, and are preferably oriented to achieve the following goals when the diodes 338 and 343 are in a non-conducting state: Prevent second circuit 140 from imposing a voltage from node 306 to node 310 that is higher than a rated output voltage of first circuit 110 from node 306 to node 310 (e.g., approximately 60 volts in the example mentioned above); and to prevent second circuit 140 from imposing a voltage from node 306 to node 310 that is negative in value. However, because the body diodes 338 and 343 allow unidirectional conduction from an AC source, it is desirable for FETs 337 and 342 to bidirectionally conduct current at the frequency of fluorescent lamp electronic ballast 122 or 123 shown in
The present inventors have discovered that, in some embodiments, it is desirable to have the foregoing isolating means both in series with the first conductor 339 and in series with the second conductor 344; this is to prevent leakage of current from first circuit 110 to LEDs 300 during intended powering of those LEDs by second circuit 140 that can give rise to flickering of LEDs 300. However, in other embodiments, for instance, where any sporadic flashing on and off and any sporadic flashing brighter of LEDs is negligible, first circuit 110 can be isolated from LEDs 300 by only one isolating means in either first conductor 339 or second conductor 344.
A variation of the foregoing isolating means in LED circuit 304 includes replacing n-channel FET 337 with a p-channel FET, a bipolar junction transistor or a silicon controlled rectifier, or with a mechanical switch. Another variation is to similarly replace p-channel FET 342 with an n-channel FET, a bipolar junction transistor, a silicon controlled rectifier or a mechanical switch.
It will be a matter of routine skill to persons of ordinary skill in the art, from comparing the descriptions of LED circuits 303 and 304 of
One or more additional LED circuit units, such as LED circuit unit 327, can be added to LED circuit 304 of
Referring again to
When using fluorescent lamp fixture 100 or 115 of
LEDs 300 in circuitry 380 of
LEDs 300 in circuitry 390 of
The use of isolation transformer 228 in
A preferred alternative exists to using the serial and parallel connected LEDs of
Bypass capacitors 262 and 263 are shown connected across selected diodes of full-wave rectifier circuit 230 to permit flow of current at the ballast frequency, as defined above to limit the charging of capacitors, such as capacitors 254 and 258, in first circuit 110 when second circuit 140 powers the LEDs. Such charging of capacitors could cause sporadic flashing on and off or sporadic flashing brighter of LEDs 300. An alternative to using bypass capacitors 262 and 263 is to use instead bypass capacitors 264 and 265, shown in phantom. Another alternative to using alternative to using bypass capacitors 262 and 263 is to use instead bypass capacitors 262 and 264, or to use instead bypass capacitors 264 and 265.
Additionally, it may be desirable to use all four capacitors 262, 263, 264 and 265, which may be desirable for some types of fluorescent lamp electronic ballasts 122 or 123 of
The foregoing LED power supplies 220 and 250 of
As shown in
Returning to circuitry 200 of
Various benefits result from using first and second circuits 110 and 140 (
Further, it is preferable that the first and second circuits 110 and 140 (
By having second circuit 140 power only a portion of the LEDs 300 powered by first circuit 110, the circuit designer has a greater degree of design choice to optimize one or both first and second circuits 110 and 140.
By having first circuit 110 power only a portion of the LEDs 300 powered by second circuit 140, the circuit designer has a greater degree of design choice to optimize one or both first and second circuits 110 and 140. For instance, it becomes easier to limit current to LEDs 300 when using a fluorescent lamp electronic ballast 122 (
As with first circuit 110 of
By having first circuit 110 of
Referring to
(1) PERMIT SECOND CIRCUIT OPERATION. First conduction control means 350 may be realized as a capacitor, for instance, for conducting power at the ballast frequency, as defined above. By “permit” second circuit operation is meant herein to provide necessary, but not sufficient, means to allow second circuit 140 to operate. In addition, the second conduction control means 370 also needs to permit second circuit operation. In other words, both first and second conduction control means 350 and 370 are necessary, and together are sufficient to enable operation of second circuit 140.
(2) PERMIT SECOND CIRCUIT TO OPERATE WITHOUT INTERFERING WITH FIRST CIRCUIT. First conduction control means 350 also may perform the function of permitting second circuit 140 to operate without interfering with first circuit 110 during intended operation of first circuit 110; that is, when the first circuit is connected to mains power via first and second power pins 104 and 106. To realize this function, conduction control means 350 is configured as a capacitor or a switch situated in the open position, for instance, to limit conduction of current from the mains to LEDs 300 via second power pin 106 and rectifier circuit 282 of second circuit 140 when first circuit 110 is operating. Such limitation of current from the mains prevents first or second substantial types of deviation of light from LEDs 300 compared to the average luminous intensity of such LEDs that would arise from first circuit 110 being standalone. First circuit 110 would be standalone if imaginary cuts 266 and 268 were made to the circuitry of
A first substantial level of deviation of light of the flicker-type and the continuous-type is 10 percent. A second substantial level of deviation of light of the flicker-type and continuous-type is 5 percent for minimizing annoying flicker-type and continuous-type deviation. Measurement of luminous intensity for purposes of calculating light flicker is well known, and may utilize a photocell to constantly measure light from a light source.
(3) LIMIT CURRENT FOR DRIVING LEDs. First conduction control means 350 may further limit current as appropriate for driving LEDs 300. First conduction control means 350 can accomplish this function when realized as a capacitor, which presents much larger impedance at mains power frequency than at the ballast frequency, as defined above. The mains power frequency is much lower than the ballast frequency, which follows from the fact that the mains frequency is in the range from zero to 500 Hz whereas the ballast frequency is typically from 20 kHz and up.
(4) PERMIT ATTAINMENT OF SHOCK HAZARD PROTECTION. A fourth possible function of first conduction control means 350 (and also of cooperating second conduction means 370) is to permit the mitigation of a potentially life-threatening electrical shock hazard from the mains when such a lamp 102 (
In the shock hazard test, the first and second conduction control means 350 and 370 can each be embodied as one of a capacitor, or a switch situated in the open position, that is configured, for each exposed power pin 104, 106, 124 and 126 of LED lamp 102, to prevent current conduction (I=V/R,
When a capacitor is used to realize either of both of first and second conduction control means 350 and 370, the value of the capacitor(s) can be beneficially chosen to further limit the current as described in the above paragraph and also in the below paragraph, both of which start with the phrase: “(2) LIMIT CURRENT FOR DRIVING LEDs.”
The maximum predetermined RMS milliamps value can be 10 at 50 Hz and at 60 Hz for any value of voltage over the mentioned range of source voltage, for instance, from 110 VAC RMS to 277 VAC RMS. The maximum predetermined RMS milliamps value is preferably even a lower value, such as S at 50 Hz and 60 Hz. The significance of these values is explained in relation to the following table:
The foregoing data was compiled by Charles Dalziel, a major researcher in the U.S.A. on the effect of electric currents in the human body, and relate to human test subjects in good health. The electrical circuitry described in the foregoing paragraph is used by UL, which is also known as Underwriter's Laboratory, to emulate the hand of a human being that touches exposed conductive circuitry of an LED lamp, and a path through the human being to earth ground. The predetermined rms milliamp value of 10 is somewhat lower than the threshold that would cause “[p]ain with loss of voluntary muscle control” for women, with the 0.5 milliamp rms difference providing a margin of safety. The comparable threshold for men is even higher (i.e., 16 milliamps rms). Loss of voluntary muscle control is dangerous because it could cause a lamp installer to fall from a 3 meter high ladder, by way of example. The lower, predetermined RMS milliamp value of 5 is the value chosen by UL in the U.S.A. at 60 Hz as meeting the UL 1598c standard in the U.S.A., which was formulated by UL for mitigating the above-mentioned potentially life-threatening electrical shock hazard to an installer of an LED lamp. From the foregoing table, it can be seen that the predetermined rms value of 5 is desirably below the threshold of “[p]ain with voluntary muscle control maintained.”
The mentioned UL 1598c standard requires testing at 60 Hz, for example, and also at frequencies that would be produced by a fluorescent lamp electronic ballast. As noted above, such ballasts can have various frequencies, typically in the range from 20 KHz to 100 KHz. The human body can tolerate a higher level of current at higher frequencies, as a comparison of the last two columns of data in the foregoing table indicates. Because the human body can tolerate a higher level of current at higher frequencies than the mentioned 50 Hz or 60 Hz, the UL 1598c standard allows the much higher current level of approximately 59 milliamps rms at 25 kHz and approximately 120 milliamps at 50 KHz, for instance.
Referring to
(1) PERMIT SECOND CIRCUIT OPERATION. Second conduction control means 370 may be realized as a capacitor, for instance, for conducting power. The word “permit” is defined above in regard to first conduction control means function (1).
(2) PERMIT SECOND CIRCUIT TO OPERATE WITHOUT INTERFERING WITH FIRST CIRCUIT. Second conduction control means 370 also may perform the function of permitting second circuit 140 to operate without interfering with first circuit 110 during intended operation of first circuit 110; that is, when the first circuit is connected to mains power via first and second power pins 104 and 106. To realize this function, conduction control means 370 is configured as a capacitor or a switch situated in the open position, for instance, to limit conduction of current from the mains to LEDs 300 via third power pin 124 and rectifier circuit 282 of second circuit 140 when first circuit 110 is operating. Mains power is supplied to third power pin 124 when using fluorescent lamp fixture 115 of
A first substantial level of deviation of light of the flicker-type and the continuous-type is 10 percent. A second substantial level of deviation of light of the flicker-type and continuous-type is 5 percent for minimizing annoying flicker-type and continuous-type deviation. Measurement of luminous intensity for purposes of calculating light flicker is well known, and may utilize a photocell to constantly measure light from a light source.
(3) LIMIT CURRENT FOR DRIVING LEDs. Second conduction control means 370 may further limit current as appropriate for driving LEDs 300. Second conduction control means 370 can accomplish this function when realized as a capacitor, which presents much larger impedance at mains power frequency than at the frequency of fluorescent lamp electronic ballast 122. The mains power frequency is much lower than the ballast frequency, which follows from the fact that the mains frequency is in the range from zero to 500 Hz whereas the ballast frequency is from 10 kHz and up.
(4) PERMIT ATTAINMENT OF SHOCK HAZARD PROTECTION. A possible function of second conduction control means 370 is to permit the mitigation of a potentially life-threatening electrical shock hazard when such a lamp 102 (
The foregoing possible functions of permitting shock hazard protection for the first and second conduction control means 350 and 370 in
For all Embodiments 1-13 as indicated in
As is well known in the art, capacitor 352 may more generally be referred to as a capacitance. The more general term “capacitance” covers the use of multiple capacitors to achieve a desired capacitance.
For all Embodiments 1-13 as indicated in
Short circuits 352 and 358 of first and second conduction control means 350 and 370 are included in the phrase “conduction control means” as used herein. However, the “control” aspect of short circuits 352 and 358 is to always be conductive. This contrasts with “control” of a switch, for instance, which can alternately be conducting and non-conducting.
Further, short circuit 352 of first conduction control means 350 is intended to enable conduction between second power pin 106 and second circuit 140. Similarly, short circuit 358 of second conduction control means 370 is intended to enable conduction between third power pin 124 and second circuit 140.
For all Embodiments 1-13, reference is made to the tabular listing in
Embodiments 1-2 and 11-13 may not achieve shock hazard protection discussed above as possible functions of the first and second current conduction control means 350 or 370. This is because Embodiments 1, 2 and 11-13 realize first conduction control means 350 as a short circuit 358. Therefore, with these embodiments, it is especially important to provide the warning on product packaging, etc., mentioned above.
In regard to Embodiments 9 and 10, both of which relate to circuitry 1400 of
In regard to Embodiments 5-10, although it is preferred to use a less costly first circuit 110 that is non-isolated, a more costly first circuit 110 that is isolated could also be used.
Referring to
Embodiment 12 uses an isolated type of LED power supply within first circuit 110, and avoids use of fluorescent lamp fixture 115 (
Embodiment 13, in which first and second conduction control means 350 and 370 are realized as short circuits 358 and 372, respectively, relies on the non-sharing of LEDs, in the sense of powering such LEDs for illumination along a length of LED lamp 102 to attain the following advantage: Non-interference by the second circuit 140 with the first circuit 110 concerning both the flicker and continuous types of interference as discussed above.
Referring to
For safety, it is desirable for any switches used to realize first or second conduction control 350 or 370 to be provided to an installer in an open, or non-conducting, state. Once an installer verifies that a lamp will be installed in either fluorescent lamp fixture 100 (
Capacitors 352 and 374 shown in
The following is a list of reference numerals and associated parts as used in this specification and drawings:
The foregoing describes an LED lamp that can be retrofit into an existing fluorescent lamp fixture and that has dual mode operation from an existing fluorescent lamp electronic ballast associated with the lamp fixture, as well as, alternatively, directly from power mains. Beneficially, the LED lamp can be configured to mitigate a potentially life-threatening electrical shock hazard when such a lamp is placed into a fixture wired to supply power directly from power mains. Some embodiments of the inventive lamp are configured to provide additional protection against shock exposure to a lamp installer.
The scope of the claims should not be limited by the preferred embodiments and examples, but should be given the broadest interpretation consistent with the written description as a whole.
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| Number | Date | Country | |
|---|---|---|---|
| 20160109070 A1 | Apr 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62066306 | Oct 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14555294 | Nov 2014 | US |
| Child | 14702591 | US |
