U.S. patent application number 15/636945 was filed with the patent office on 2017-10-19 for light strip and method for making a light strip.
The applicant listed for this patent is Jason GREENE. Invention is credited to Jason GREENE.
Application Number | 20170299132 15/636945 |
Document ID | / |
Family ID | 55961328 |
Filed Date | 2017-10-19 |
United States Patent
Application |
20170299132 |
Kind Code |
A1 |
GREENE; Jason |
October 19, 2017 |
LIGHT STRIP AND METHOD FOR MAKING A LIGHT STRIP
Abstract
A light strip has a flexible enclosure extruded around a pair of
conductors. The enclosure contains a lighting assembly with one or
more flexible substrates populated with a plurality of light
circuits. The substrates are spaced from the pair of conductors.
The lighting assembly has a plurality of connecting devices for
electrically coupling the lighting assembly to the pair of
conductors.
Inventors: |
GREENE; Jason; (Massapequa,
NY) |
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Applicant: |
Name |
City |
State |
Country |
Type |
GREENE; Jason |
Massapequa |
NY |
US |
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|
Family ID: |
55961328 |
Appl. No.: |
15/636945 |
Filed: |
June 29, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15499474 |
Apr 27, 2017 |
9746144 |
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15636945 |
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15007316 |
Jan 27, 2016 |
9671075 |
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15499474 |
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14726764 |
Jun 1, 2015 |
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15007316 |
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62006382 |
Jun 2, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05B 45/00 20200101;
H05K 1/00 20130101; F21Y 2103/10 20160801; H05B 33/08 20130101;
Y02B 20/343 20130101; H05B 45/40 20200101; H05K 1/189 20130101;
F21V 23/06 20130101; H05B 45/395 20200101; F21V 23/02 20130101;
H05K 2201/10106 20130101; F21S 4/22 20160101; F21Y 2115/10
20160801; Y02B 20/30 20130101; F21V 19/0025 20130101 |
International
Class: |
F21S 4/22 20060101
F21S004/22; F21V 23/06 20060101 F21V023/06; F21V 19/00 20060101
F21V019/00; H05B 33/08 20060101 H05B033/08; F21V 23/02 20060101
F21V023/02 |
Claims
1. A light strip assembly comprising: a light strip comprising a
pair of conductors, a flexible enclosure extruded around said pair
of conductors and a lighting assembly electrically coupled to said
pair of conductors; and an end member comprising a cup-shaped shell
having a wall, said cup-shaped shell being sized to fit over an end
of said flexible enclosure.
2. The light strip assembly according to claim 1, wherein said
flexible enclosure has a periphery with an asymmetrical
cross-section and said cup-shaped shell is keyed to fit over only
one end of said flexible enclosure.
3. The light strip assembly according to claim 1, wherein said end
member comprises a capping device.
4. The light strip assembly according to claim 1, wherein said end
member comprises a connector, said wall supports a first pair of
pins projecting from a first side of said wall and said first pair
of pins is adapted to be inserted into said pair of conductors.
5. The light strip assembly according to claim 4, further
comprising a second light strip comprising a second pair of
conductors, a second flexible enclosure extruded around said second
pair of conductors and a second lighting assembly electrically
coupled to said second pair of conductors; wherein said connector
comprises a splicing connector, and said wall supports a second
pair of pins projecting from a second side of said wall opposite
said first side and said second pair of pins is adapted to be
inserted into said second pair of conductors.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/499,474 filed on Apr. 27, 2017 which is a
continuation of U.S. patent application Ser. No. 15/007,316 filed
on Jan. 27, 2016 (now U.S. Pat. No. 9,671,075) which is a
continuation of U.S. patent application Ser. No. 14/726,764, filed
on Jun. 1, 2015, which claims the benefit of U.S. Provisional
Patent Application Ser. No. 62/006,382, filed on Jun. 2, 2014. The
contents of each of the afore-mentioned applications are hereby
incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to lighting strips and methods
for making the same, and in particular to extrusions and extrusion
methods for such light strips.
2. Description of Related Art
[0003] Flexible printed circuit boards have been manufactured in
strips that are populated with light emitting diodes. The strips
can be mounted in a transparent tubular sleeve that is easily
mounted in a variety of locations. These lighting strips can be
placed inside cabinets, along corridors to light a walkway, or any
place where a compact lighting source is required.
[0004] Light emitting diodes have relatively small forward voltage
drops and therefor require a voltage conversion unit such as a
transformer, which adds to the complexity of the installation. Also
known light strips have included ASICs to regulate the applied
voltage, but these ASICs tend to be large, generate much heat, and
have a tendency to pull off the underlying, flexible printed
circuit board.
[0005] Known lighting strips have flexible circuit boards that
carry both the lighting elements and buses that carry power
throughout the strip. When the strip is relatively long, the buses
must carry significant current that tends to heat a flexible
circuit board and degrades the performance of the adjacent LEDs,
possibly causing them to fail. Many applications require an
especially long lighting strip. In such cases a number of shorter
strips are spliced together and mounted in a common sleeve, end to
end. In this case the buses on each strip are serially connected
and must carry current for all the lighting elements in the several
strips. Such a common bus carries even more current, and generates
even more heat that seriously affects the lighting elements.
[0006] Also, it can be difficult to mount in a single sleeve, long
lighting strips or a number of serially connected lighting
strips.
[0007] See also U.S. Pat. Nos. 3,786,173; 4,032,210; 4,990,098;
5,032,960; 5,296,648; 5,337,225; 5,559,681; 5,681,179; 5,833,358;
6,113,248; 6,244,893; 6,673,292; 6,773,286; 7,249,980; 7,753,577;
8,052,303; 8,262,250; 8,398,262; 8,635,769; 8,641,229; and
8,714,772.
SUMMARY OF THE INVENTION
[0008] In accordance with the illustrative embodiments
demonstrating features and advantages of the present invention,
there is provided light strip including a pair of conductors, and a
flexible enclosure extruded around the pair of conductors. The
light strip also has a lighting assembly including one or more
flexible substrates positioned within the enclosure and populated
with a plurality of light circuits. The one or more substrates are
spaced from the pair of conductors. The lighting assembly has a
plurality of connecting devices for electrically coupling the
lighting assembly to the pair of conductors.
[0009] In accordance with another aspect of the invention, a method
is provided for making a light strip having a pair of conductors
and one or more flexible substrates populated with a plurality of
light circuits. The method includes the step of extruding a plastic
material around the pair of conductors to form a flexible enclosure
sized to encompass the one or more flexible substrates and maintain
a spacing between the pair of conductors and the one or more
flexible substrates.
[0010] By employing apparatus and methods of the foregoing type an
improved lighting strip is achieved using techniques that ease
manufacture and assembly. In a disclosed embodiment a transparent
sleeve is extruded around a pair of conductors that supply power to
the lighting strip. The flexible printed circuit board carrying the
LEDs is spaced from these supply conductors and are not overheated
by them. In this embodiment a flexible circuit board has a number
of separate strings of LEDs whose current is limited either by a
resistor or a depletion mode field effect transistor. Each string
of LEDs on the flexible circuit board has its own dedicated pair of
solder pads that are each connected to one end of a jumper whose
other end connects to one of the supply conductors.
[0011] These disclosed jumpers may be soldered in place in advance,
so that the flexible circuit board and supply conductors are
simultaneously coextruded into a flexible sleeve, with extrudate
partially enveloping the jumpers. The printed circuit board is not
enveloped by the extrudate to avoid trapping it in an insulating
layer that prevents heat dissipation.
[0012] In some cases the flexible sleeve can be extruded around
just the supply conductors and part of the jumpers, which jumpers
to or connected to the supply conductors but not to the missing
flexible circuit board. In that case the sleeve will have a
longitudinal slit (a split). The split in can be opened with an
appropriate tool that allows an end of the flexible circuit board
to be inserted into this sleeve. Thereafter the tool is slid back
to open progressive positions in the longitudinal split, allowing
the rest of the flexible strip to be placed inside the sleeve.
Thereafter, an assembler can solder the free ends of the jumpers to
the solder pads on the flexible circuit board.
[0013] In either case, a number of separate flexible printed
circuit boards can be installed end to end, but instead of being
directly interconnected, they are simply connected to the supply
conductors embedded in the flexible sleeve.
[0014] The disclosed LEDs have a relatively high forward voltage
drop. This allows one to apply a higher voltage to a string of
LEDs. In a disclosed embodiment the LEDs are arranged to handle the
rectified line voltage from an ordinary utility line, without the
need for a stepdown transformer or other device for reducing the
voltage applied to the lighting circuit. The rectifying circuit can
be placed in a housing that is in line with a cord having with a
plug that connects to an ordinary utility outlet. Alternatively,
the rectifier circuit can be placed in a junction box and hardwired
to a power line. A separate cable can run from the junction box to
the lighting strip.
[0015] In a disclosed embodiment, this rectified line voltage is
applied to the lighting strip with a connector having a shell
containing a pair of pointed pins. When the connector is pushed
onto a lighting strip the pointed pins are inserted into the
coextruded supply conductors which are made of stranded wires that
are easily invaded by the pointed pins. The shell of the connector
matches the asymmetrical periphery of the flexible sleeve
containing the flexible printed circuit board. The asymmetry is
arranged such that the connector can only be placed on one and of
the flexible sleeve to avoid a reversed polarity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above brief description as well as other objects,
features and advantages of the present invention will be more fully
appreciated by reference to the following detailed description of
illustrative embodiments in accordance with the present invention
when taken in conjunction with the accompanying drawings,
wherein:
[0017] FIG. 1 is a schematic diagram of a light circuit in
accordance with principles of the present invention;
[0018] FIG. 2 is a schematic diagram of a rectifier circuit that
may be used in connection with the circuit of FIG. 1;
[0019] FIG. 3 is a schematic diagram of a light circuit that is an
alternate to that of FIG. 1;
[0020] FIG. 4 is a schematic diagram of the light circuit of FIG. 1
or 3 replicated and segregated into separate groups that are each
mounted on a flexible substrate to formal light strip;
[0021] FIG. 5 is a fragmentary, plan view of an upper copper
lamination that is part of the substrate associated with the
circuit of FIG. 4;
[0022] FIG. 6 is a fragmentary, plan view of a lower copper
lamination that is part of the substrate associated with the
circuit of FIG. 4;
[0023] FIG. 7 is a cross-sectional view of a flexible enclosure
containing the substrate of FIGS. 4-6 to form a light strip;
[0024] FIG. 8 is a cross-sectional view of a the used to extrude
the arrangement of FIG. 7;
[0025] FIG. 9 is a cross-sectional view of extrusion that is an
alternate to that of FIG. 7;
[0026] FIG. 10 is a perspective view of the extrusion of FIG. 9
being partially opened with tool that is being used to insert the
substrate of FIGS. 4-6;
[0027] FIG. 11 is a fragmentary, perspective view of a connector
being used to connect to the light strip of FIG. 7;
[0028] FIG. 12 is a perspective of the connector of Figure of 11
connected to a rectifier circuit;
[0029] FIG. 13 is an elevational view, partly in cross-section,
showing to a housing that contains a rectifier circuit that is an
alternate to that of FIG. 12; and
[0030] FIG. 14 is in end view of a clip used to hold the light
strip of FIG. 7.
DETAILED DESCRIPTION
[0031] Referring to FIG. 1, the illustrated light circuit has six
serially connected LEDs, D1, D2, D3, D4, D5, and D6, in that order
(hereinafter LEDs D1-D6). LEDs D1-D6 are connected cathode to anode
and are all connected to be forwardly biased by a positive
potential at terminal V1. The anode of diode D1 is directly
connected to terminal V1, while the cathode of diode D6 is directly
connected to drain D of depletion mode field effect transistor Q1
(FET transistor Q1). In one embodiment transistor Q1 was a model
CPC3708 transistor supplied by IXYS, Integrated Circuits Division,
although other types of transistors from other suppliers may be
used in other embodiments. Gate G of transistor Q1 is grounded, and
its source S is connected through a parallel pair of resistors R1
and R2 to ground. Accordingly, the power input to this light
circuit is applied across terminal V1 and ground.
[0032] Configured in this manner, transistor Q1 will conduct when
relatively small voltage is applied across the transistor, but will
shut off when the voltage increases. Initially, the voltage at
terminal V1 must at least exceed the sum of the forward voltage
drops across diodes D1-D6. Thereafter, the shutoff voltage is
determined by the characteristics of transistor Q1, the forward
voltage drop of diodes D1-D6, and the resistance of resistors R1
and R2 (having a net resistance of, for example, 66.5 Ohms).
[0033] In this embodiment a full wave rectified voltage is applied
between terminal V1 and ground, so that a unipolar, fluctuating
sine wave is applied in each half cycle. Accordingly, transistor Q1
conducts once the combined forward voltage drop is reached and
diodes D1-D6 begin to conduct, but stops conducting when the input
voltage becomes too large. The conduction angle of transistor Q1
can be tailored to accommodate the number and the rating of diodes
D1-D6. Thus, transistor Q is a power restricting device.
[0034] In this embodiment, the six diodes D1-D6 each have a forward
voltage drop of 24 V, that is, a total voltage drop of 144 V. Other
embodiments are anticipated. For example some embodiments may use
four serially connected diodes, each having a forward voltage drop
of 36 V, that is, a total voltage drop of 144 V. It will be
appreciated that the total voltage drop can be modified for some
embodiments, depending on whether one desires a larger or smaller
conduction angle, the ratings of the diodes, the available line
voltage, etc. Good results are achieved when the forward voltage
drop of each of the LEDs exceeds 8 V.
[0035] Referring to FIG. 2, a rectifier circuit is illustrated for
providing the power input for the light circuit of FIG. 1. In FIG.
2, a source of alternating current VAC, which may be the ordinary
power supplied by a local utility, connects through fuse F1 across
metal oxide varistor MOV1, which provides surge protection.
Capacitor C1 is connected in parallel with varistor MOV1 to
suppress RF transmission and interference. A conventional full wave
bridge 11 has its input connected across capacitor C1 to produce an
output 12. It will be understood that half-wave bridges may be used
or other type of rectification arrangements may be used instead.
Good results are achieved when the time-varying voltage at output
12 has a peak voltage greater than 100 V.
[0036] Referring to FIG. 3, the previously illustrated transistor
(transistor Q1 of FIG. 1) was replaced with current limiting
resistors R3 and R4 (which constitute another power restricting
device). Specifically, diodes D7, D8, D9, D10, D11, and D12 are
serially connected as before (cathode to anode) in that order.
However, resistor R3 is serially connected between diodes D8 and
D9, and resistor R4 is serially connected between diodes D10 and
D11. This string is connected between previously mentioned terminal
V1 and ground.
[0037] Referring to FIG. 4, a light strip is schematically
illustrated as two flexible substrates 14 and 16, mounted end two
end. While two substrates are illustrated, it will be understood
that some embodiments may employ only one substrate, or more than
two substrates. In this embodiment substrates 14 and 16 are
identical and each have four identical lighting circuits M1, M2,
M3, and M4. Each of these circuits M1-M4 is that shown in the FIG.
1. While the given number of lighting circuits M1-M4 is four, in
other embodiments a different number may be employed. Terminal V1
is that previously illustrated, while ground is identified as
terminal GRD.
[0038] In this diagram substrates 14 and 16 are illustrated with
their longer, lateral edges running right and left. Each of the
light circuits M1-M4 have a pair of solder pads connected to
terminal V1 and a pair of solder pads connected to terminal GRD.
Specifically, circuit M1 has solder pads P1 and P2 connected to its
terminal V1, circuit M2 has solder pads P3 and P4 connected to its
terminal V1, circuit M3 has solder pads P5 and P6 connected to its
terminal V1, and circuit M4 has solder pads P7 and P8 connected to
its terminal V1. Also, circuit M1 has solder pads G1 and G2
connected to its terminal GRD, circuit M2 has solder pads G3 and G4
connected to its terminal GRD, circuit M3 has solder pads G5 and G6
connected to its terminal GRD, and circuit M4 has solder pads G7
and G8 connected to its terminal GRD.
[0039] A pair of conductors 18 and 20 are shown positioned adjacent
to substrates 14 and 16, on opposite sides of the substrates 14 and
16. Power is supplied to conductors 18 and 20 by rectifying circuit
22, which is as illustrated in FIG. 2. In particular, conductor 20
receives the high potential while conductor 18 is ground.
[0040] Each of the lighting circuits M1-M4 has a separated pair of
leads (jumpers) acting as a connecting device to conductors 18 and
20. Specifically, lead J1 is soldered between pad P2 and conductor
20, while lead J5 is soldered between pad G1 and conductor 18.
Also, lead J2 is soldered between pad P4 and conductor 20, while
lead J6 is soldered between pad G3 and conductor 18. Lead J3 is
soldered between pad P6 and conductor 20, while lead J7 is soldered
between pad G5 and conductor 18. Lead J4 is soldered between pad P8
and conductor 20, while lead J8 is soldered between pad G7 and
conductor 18. It will be understood that different pads may be used
as a matter of convenience. For example, lead J1 could be connected
between pad P1 and conductor 20.
[0041] It will be noted that substrates 14 and 16 are not directly
interconnected and thus can be severed along line 24. In fact, none
of the four light circuits M1-M4 on substrates 14 and 16 are
directly interconnected and thus each substrate can be severed into
quarters (one quarter, two quarters, or three quarters). In the
case of severing, another rectifier circuit, similar to circuit 22,
may be connected to the left ends of the conductors 18 and 20
remaining in the severed segment, and that segment will be able to
operate without any negative effect caused by the severing.
[0042] Referring to FIGS. 5 and 6, a complementary pair of copper
laminations 24 and 26 are designed to be registered as shown and
attached by appropriate adhesives to opposite sides of an
intervening layer of polyamide, before being covered with a
conventional solder mask (not shown). In the usual fashion, the
copper laminations have been etched while on the polyamide with the
portions removed by etching illustrated herein in the color black.
Laminations 24 and 26 are designed to implement the circuit of FIG.
1, and the illustrated portion will repeated on the remaining
(unillustrated) portions to implement the substrate of FIG. 4
(substrate 14 or 16).
[0043] Lower lamination 26 is shown having previously mentioned
solder pads P1, P2, G1, and G2 in the upper left corner, upper
right corner, lower left corner, and lower right corner,
respectively. Pads P1 and P2 are interconnected by run B1, while
pads G1 and G2 are interconnected by run B11. In this embodiment
plated-through holes connect between upper and lower laminations 24
and 26, in order to separately connect lower pads P1, P2, G1, and
G2 to upper pads P1', P2', G1', and G2', respectively. Pads P1 and
P2' are interconnected by run A1, while pads G1' and G2' are
interconnected by run A11.
[0044] Lamination 24 is shown segregated into isolated segments A1,
A2, A3, A4, A5, A6, and A7. Segments A8 and A10 are interconnected
by run A9.
[0045] Components previously mentioned in FIG. 1 are shown in
phantom as follows: (a) diode D1 connecting between segments A1 and
A2, (b) diode D2 connecting between segments A2 and A3, (c) diode
D3 connecting between segments A3 and A4, (d) diode D4 connecting
between segments A5 and A6, (e) diode D5 connecting between
segments A6 and A7, and (f) diode D6 connecting between segments A7
and A8.
[0046] Plated-through holes W1/W1' connect together segments A4 and
B4, while plated-through holes W2/W2' connect together segments B4
and A5. The net effect of these plated through holes is to connect
together segments A4 and A5. It will be appreciated that the
foregoing provides a serial connection of diodes D1-D6 from pad P2
to run A9.
[0047] Run A9 leads to segment A10 and previously mentioned
transistor Q1 (shown in phantom) is mounted with its drain
connected to segment A10. Run A11 has a spur A11' that ends in a
pad that connects to the gate of transistor Q1. Isolated pad A12
connects on one end to the source of transistor Q1, and on the
opposite end to one terminal of each of the resistors R1 and R2
(also shown in phantom), whose other terminals connect to run A11.
It will be appreciated that the foregoing arrangement produces the
circuit previously described in FIG. 1.
[0048] It will be noticed that in lamination 26 segments B2, B3,
B6, and B7 are isolated and are not designed to carry current.
Instead, these segments are used as heat sinks to dissipate heat
generated by components mounted atop upper lamination 24. In
particular, segments B2, B3, B6, and B7 thermally connect through
plated-through holes H1/H1', H2/H2', H3/H3', H4/H4', respectively,
to respective segments A2, A3, A6, and A7. In addition, segment B10
thermally connects through plated-through holes H6/H6' to segment
A10. Plated-through holes H1/H1', H2/H2', H3/H3', H4/H4',and H6/H6'
are referred to herein as a dedicated portion of the plated-through
holes, designed to conduct heat without conducting current.
[0049] It will be appreciated that the foregoing pattern repeats
and that each repetition can operate independently. Each adjacent
repetition can be separated as desired by severing them apart at
cutline 28/28'. The solder mask (not shown) covering laminations 24
and 26 can be marked to indicate the cutlines. As previously
described, power is applied to the illustrated light circuit by
applying a supply voltage between runs A1 and A11 and for this
purpose one of the pads P1, P2 is paired with one of the pads G1,
G2 to connect to conductors 18 and 20 and act as a supply
source.
[0050] The ten plated-through holes 30/30' (five pairs) connecting
between segments A2 and B2 are designed to receive a non-functional
component such as dummy resistor (not shown). This nonfunctional
component can be soldered into one of five positions, which signify
a quality of the lighting strip. For example, the solder mask (not
shown) at holes 30/30' can be marked to indicate a color
temperature of the LEDs D1-D6 (e.g., 5000 K, 4000 K, 3000 K, 2700
K, or 2400 K).
[0051] Referring to FIG. 7, flexible enclosure 40 is an extrusion
of thermoplastic material, such as PVC, a high density
polyethylene, polychlorotrifluoroethylene, an ionomer resin, or
other plastic material. Enclosure 40 has a periphery with an
asymmetrical cross-section specifically, enclosure 40 has a pair of
ridges 40A and 40B on one side, and on the other side a single
ridge 40C, which is at a different elevation than either of the
ridges 40A and 40B. These asymmetrical ridges serve a purpose that
will be described presently. In this embodiment enclosure 40 has an
overall width of 1 inch (2.5 cm) and overall thickness of 3/8 inch
(1 cm), although other dimensions may be employed depending on the
available space, the materials used, the size and rating of the
LEDs and other components, etc.
[0052] Enclosure 40 is tubular and has a longitudinal tunnel 38
containing a lighting assembly, which includes printed circuit
board 32 (board 32 also referred to as a substrate) populated with
the electrical components previously described in connection with
FIGS. 4-6. Diode D1 is visible in this view. This assembly is
identified as light strip 10.
[0053] Light strip 10 also has the leads J1-J8 illustrated in FIG.
4. Leads J1 and J5 visible in this view and are shown soldered on
the outside end to conductors 18 and 20, respectively, and on the
inside end to respective positions 34 and 36 at substrate 32.
Positions 34 and 36 correspond to previously mentioned solder pads
(pads G1 and P2 of FIG. 4). It will be noticed that enclosure 40 is
extruded completely around conductors 18 and 20, and is partially
extruded around an outside portion of leads J1 and J5. In this
embodiment conductors 18 and 20 are each made of stranded wire.
[0054] Longitudinal tunnel 38 is generally rectangular but has
longitudinal slots 38A and 38B for holding the lateral edges of
substrate 32, and longitudinal gutter 38C that provides space for
heat dissipation.
[0055] Referring to FIGS. 7 and 8, die 140 of FIG. 8 is designed to
extrude the previously mentioned enclosure 40 of FIG. 7.
Specifically, the inside of die 140 has flat upper and lower walls,
a right sidewall having channels 140A and 140B for forming
previously described ridges 40A and 40B of FIG. 7. The left inside
wall of die 140 has a channel 140C for forming ridge 40C of FIG.
7.
[0056] A die 138 is nested inside die 140 and is supported on top
by posts 142A, 142B, 142C, and 142D, and from below by lower posts
144A, 144B, 144C, and 144D. The direction of extrusion is out of
the drawing of FIG. 8, and the posts 142A-142D and 144A-144D are
set back enough that extrudate will flow around them without
leaving gaps. Previously mentioned substrate 30 is shown traveling
inside die 138 in the same direction as the extrudate.
[0057] The previously mentioned tunnel 38 of FIG. 7 is formed by
internal die 138 which has approximately the same peripheral
outline as the tunnel, including protrusion 138C for forming gutter
38C, and protrusions 138A 138B for forming slots 38A and 38B. Die
138 deviates from the outline of tunnel 38 in the case of
protrusions 138D and 138E on the right, and protrusions 138F and
138G on the left. Protrusions 138D and 138G are formed by
quarter-cylindrical walls that provide clearance for leads J5 and
J1, respectively, as well as for the other leads that follow behind
them. Protrusion 138E and 138F include semicylindrical walls that
provide clearance for previously mentioned conductors 18 and 20,
respectively.
[0058] In FIG. 7 conductors 18 and 20 as well as the adjacent
portions of leads J1 and J5 are embedded inside the plastic
material of enclosure 40. To allow such an embedding, walls
138D-138G of FIG. 8 may have slits or apertures that allow
extrudate to flow around conductors 18 and 20 and leads J1 and
J5.
[0059] Also, after the first extrusion stage, the combined
enclosure 40 and substrate 32 may be sent through a second die that
compresses the enclosure, completes the flow of extrudate around
conductors 18 and 20, and embeds the edges of substrate 32 inside
notches 38A and 38B.
[0060] The overall length of the resulting light strip will depend
on the number of substrates 32 that are installed. The individual
substrates will be preassembled end to end and pre-wired to
conductors 18 and 20. If, for example, nine substrates 32 that are
each 16 inches (40 cm) long are assembled end to end, the overall
length will be 12 feet (or twice that length with eighteen
substrates 32). Since each substrate 32 has four banks (four of the
circuits of FIG. 1), each substrate can be quartered as previously
described in connection with FIG. 4. Two and a quarter substrates
can be a abutted end to end to produce an overall length of 3 feet
(or double those amounts to produce an overall length of 6
feet).
[0061] Referring to FIG. 9, an alternate flexible enclosure 240 is
extruded in the absence of the substrate (substrate 32 of FIG. 8).
Enclosure 240 has the same cross-section as enclosure 40 of FIG. 7
except for a longitudinal split 246. Accordingly, components
corresponding to that of FIG. 7 have the same reference numeral,
except they are increased by 200. Longitudinal split 246 splits the
previously mentioned gutter (gutter 38C of FIG. 7) into two gutter
halves, 238C and 238C'.
[0062] As before, enclosure 240 is extruded around conductors 18
and 20. While enclosure 240 is again partially excluded around
leads J11 and J12 (and the corresponding leads that follow), the
leads are routed differently and emerge into gutter 238C/238C'.
Since leads J11 and J12 follow a more tortuous path, they are
longer. As will be explained presently, longitudinal split 246 is
used as an opening for installing the previously mentioned
substrate.
[0063] Referring to FIG. 10, previously mentioned enclosure 240 is
shown lying with its longitudinal split 246 facing up. At one
location split 246 is spread apart enough to insert the distal
(forward) end of tubular spreading tool 248 between the split's
opposing walls 246A and 246B. Previously mentioned substrate 32 is
shown inserted through tool 248 to lie inside tunnel 238 as shown
at the distal end of enclosure 240. The distal end of enclosure 240
can be squeezed lightly to hold the distal end of substrate 32 in
place, as tool 248 is drawn backwardly. As tool 248 is drawn
backwardly (moving proximally), the spread-apart sector moves, and
this moving sector allows more and more of substrate 32 to pass
through the tool and fall into position inside enclosure 240.
[0064] In FIG. 10 previously mentioned diodes D5 and D6 are in one
light circuit, and diode D1 is in the succeeding light circuit.
(These diodes are shown in phantom in FIG. 10 because they are on
the reverse side of substrate 32.) As previously described,
individual lighting circuits can operate independently and can be
severed apart. For this reason the solder mask of substrate 32 has
been marked at position 48 with a straight line overlaid with a
scissors symbol to specifically indicate where to cut the
substrate. It will be appreciated that the solder mask on the
reverse side of substrate 32 can be also marked to indicate the
cutline. These cutlines can be used when the assembler desires to
make a light strip shorter than substrate 32.
[0065] In some cases the assembler will want a light strip that is
longer than substrate 32, whose length in one embodiment was 16
inches (40 cm). In such a case, a new substrate will be inserted
immediately following the first substrate. In practice a number of
successive substrates can be inserted in this fashion to produce a
light strip of various lengths. The last substrate that is inserted
can be cut at one of the designated cutlines to trim the light
strip to the desired length.
[0066] As noted before in connection with FIG. 9, the embedded
leads J11 and J12 will emerge from the opposing faces of gutter
halves 238C and 238C'. This feature is depicted in FIG. 10 with
lead J14 emerging from gutter half 238C' in wall 246A of split 246,
and lead J15 emerging from gutter half 238C in wall 246B of split
246. It will be noticed that lead J14 is associated with the light
circuit to the left of cutline marking 48, while lead J15 is
associated with the next light circuit to the right of cutline 48.
Such leads will emerge once on wall 246A and once on wall 246B for
every light circuit (i.e., once on each wall for every six diodes
D1-D6, or once on each wall for every interval between
cutlines).
[0067] The assembler will push substrate 32 past leads such as
leads J14 and J15, and will use a pick (not shown) to pull them
outwardly so they are accessible through split 246. Thereafter,
when all these substrates 32 destined for enclosure 240 are in
place, the assembler may will use tool 248 to open split 246 at
every location where a connection must be made to leads, such as
leads J14 and J15. So for example, leads J14 and J15 will be
soldered to pads G2 and P1, respectively, which are shown in this
Figure on the opposite sides of cutline 48.
[0068] The assembly is completed by sealing split 246. This may be
done by sending enclosure 240 through a die that compresses the
enclosure and applies heat to the split 246 to weld it closed.
[0069] Referring to FIG. 11, connector 350 has a cup-shaped shell
352 with a rear wall 352A (shown in phantom) supporting a pair of
pointed pins 354 and 356. The inside of shell 352 is designed to
fit around flexible enclosure 40 of the light strip 10. In
particular, groove 340C on the inside of shell 352 is designed to
fit around ridge 40C. Grooves 340A and 340B are shaped to fit
around corresponding ridges on enclosure 40 (ridges 40A and 40B of
FIG. 7). Accordingly, connector 350 is keyed to enclosure 40 by
means of grooves 340A, 340B, and 340C. Because the keying is
asymmetrical, connector 350 will only fit over one end of enclosure
40 and will be unable to fit on the opposite end, even if the
connector is rotated 180 degree.
[0070] When shell 352 is pressed over enclosure 40 of light strip
10 pointed pins 354 and 356 are inserted into conductors 18 and 20
(FIG. 7), respectively. Since conductors 18 and 20 are each made of
stranded wire, pointed pins 354 and 356 are able to insinuate
themselves into the strands and make electrical contact
therewith.
[0071] Referring to FIG. 12, previously mentioned connector 350 is
shown with its pointed pins 354 and 356 connecting through wall
352A to a pair of wires 358 and 360 that are routed through cable
362 to housing 364. Housing 364 contains the circuit shown in FIG.
2 and that circuit's output 12 connects to wires 358 and 360 of
FIG. 12. The power input VAC of the circuit of FIG. 2 is
represented in FIG. 12 as line 366 terminating in utility plug 368
designed to receive line voltage from an ordinary electrical
outlet.
[0072] Referring to FIG. 13, housing 464 contains the circuit shown
in FIG. 2, and that circuit's power input VAC is received through
wire pair 466 of line 468, which is hardwired to one of the power
lines in a building. The output of the circuit in housing 464 is
routed through a wire pair in cable 462 to the previously
illustrated connector (connector 350 of FIG. 12). The foregoing
arrangement is intended for a more permanent installation or
heavy-duty application. With this in mind, housing 464 is attached
to cover 470 of a utility box 472 that is attached to structural
component 474 (for example, a wall stud inside a wall). Such an
installation may be useful for certain high-power applications. To
accommodate a high power environment, housing 464, in this
embodiment, is an aluminum casting with cooling fins 464A.
[0073] Referring to FIG. 14, clip 576 is a U-shaped channel
designed to hold light strip 10 of FIG. 7. Clip 576 has a pair of
opposing walls 576A and 576B that are barbed on top to capture the
light strip 10. Floor 576C has ridges and grooves that provide an
air passage under the light strip to allow heat dissipation. Clip
576 may be manufactured in a variety of lengths and can be cut to
match the length of the specific light strip being installed.
[0074] To facilitate an understanding of the principles associated
with the foregoing apparatus, its operation will be briefly
described. A manufactured length of light strip 10 of FIG. 7 (or
the light strip associated with the embodiment of FIG. 9) can be
trimmed to a desired length by cutting through enclosure 40 at the
position indicated by markings 48 (FIG. 10) or between abutting
substrates 32. Severing in this manner will not end affect the
integrity of any of the light circuits shown in FIG. 1. As shown in
FIG. 4 the light circuits are arranged in separate banks, each bank
containing four light circuits M1-M4. Because each of the light
circuits M1-M4 are autonomous an installer can sever the light
strip between any of the light circuits. Thus, an installer can cut
between light circuits M1 and M2, between light circuits M2 and M3,
or between light circuits M3 and M4. The installer can also cut a
light strip between adjacent substrates, that is, cutting along
dividing line 24 of FIG. 4 to separate substrate 14 from substrate
16.
[0075] In some cases, the overall length of the available light
strip will be insufficient. In such a case a splicing connector
(not shown) can be used that has a shell 352 as shown in FIG. 11,
but will be open on opposite sides of wall 352A. In this case, wall
352A will still have the pins 354 and 356 projecting from one side
of the wall, but will have on the opposite side another pair of
pointed pins that align with pins 354 and 356. Thus the conductors
18 and 20 in one light strip will be spliced together with the
corresponding conductors 18 and 20 in the other light strip.
[0076] The end of the light strip that is not destined to receive
such a splicing device or the connector of FIG. 11 will be capped
by a cup-shaped device (not shown). This capping device will have
substantially the same shape as the distal portion of shell 352,
will lack connector pins, and the outline of its mouth will be the
mirror image of that shown in FIG. 11. Because this capping device,
as well as connector 350, make intimate contact with the periphery
of enclosure 40, there is little chance of humidity or dust
reaching the inside of the enclosure to adversely affect the
operation of the light strip. The quality of these seals can be
enhanced by using an appropriate adhesive or caulk.
[0077] Light strip 10 can be installed by first securing the clip
of FIG. 14 in place using adhesive, screws, nails, or other
fastening devices. Connector 350 can be a pushed onto the end of
light strip 10 as shown in FIG. 11, before or after snapping the
light strip into clip 576. Power can be supplied to connector 350
by using either the arrangement of FIG. 12 or FIG. 13. A light
switch (not shown) can be employed to turn light strip 10 on or
off.
[0078] Conductors 18 and 20 supply power to each of the light
circuits M1-M4 (FIG. 4) that are contained in the trimmed light
strip. It will be noticed from FIG. 4 that substrate 14 (as well as
substrate 16) need not carry current between individual light
circuits M1-M4 and the greatest current flowing on a substrate is
that needed to power an individual light circuit. Thus, while
conductors 18 and 20 may be carrying relatively high current to
supply a large number of light circuits, the amount of current
tapped off through each of the leads J1-J8 is only that needed to
supply power to an individual one of the light circuits M1-M4.
Therefore, the current flowing on substrate 14 (or substrate 16 and
its successors) is relatively small and no heat is generated to an
extent that the operation of LEDs D1-D6 or transistor Q1 (FIG. 1)
will be degraded.
[0079] As previously described in connection with FIG. 1, the
current through LEDs D1-D6 will be limited by transistor Q1. When
the half wave line voltage applied to terminal V1 reaches a voltage
exceeding the sum of the forward conduction voltage drops of LEDs
D1-D6, current will begin to flow. Current will begin to
immediately flow at this stage since depletion mode, field effect
transistor Q1 is arranged to immediately conduct when there is a
small voltage at its drain D. As the voltage at terminal V1
continues to increase, eventually the voltage between gate G and
source S of transistor Q1 becomes large enough to shut off the
transistor thereby avoiding excessive current through LEDs D1-D6.
The values of resistors R1 and R2 are selected to control this
shutoff point. The foregoing process reduces the conduction angle,
reduces heat, and allows tighter current control. In addition, the
foregoing circuit can operate with a dimmer of the type that
functions by reducing the conduction angle or by scaling down the
amplitude of the AC voltage.
[0080] It is appreciated that various modifications may be
implemented with respect to the above described embodiments. The
illustrated light strips can be modified to have a different number
of LEDs, which can be arranged in multiple rows or staggered in
some other fashion. Also the various dimensions can be altered
depending upon the desired light output, temperature stability,
space available, etc. Instead of the above described extrusion,
some embodiments may enclose a substrate by potting materials such
as silicone, or the assembly may be made by overmolding, or by
other processes.
[0081] Obviously, many modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described.
* * * * *