U.S. patent application number 13/101416 was filed with the patent office on 2011-08-25 for led array grid, method and device for manufacturing said grid and led component for use in the same.
This patent application is currently assigned to KONINKLIJKE PHILIPS ELECTRONICS N.V.. Invention is credited to Cornelis SLOB, Johannes WEEKAMP.
Application Number | 20110204392 13/101416 |
Document ID | / |
Family ID | 38374150 |
Filed Date | 2011-08-25 |
United States Patent
Application |
20110204392 |
Kind Code |
A1 |
WEEKAMP; Johannes ; et
al. |
August 25, 2011 |
LED ARRAY GRID, METHOD AND DEVICE FOR MANUFACTURING SAID GRID AND
LED COMPONENT FOR USE IN THE SAME
Abstract
Disclosed herein is a method for producing an LED array grid
including the steps of (i) arranging N electrically conducting
parallel wires, where N is an integer >1, thus creating an array
of wires having a width D perpendicular to a direction of the
wires, (ii) arranging LED components to the array of wires such
that each LED component is electrically coupled to at least two
adjacent wires, (iii) stretching the array of wires such that the
width D increases, and arranging the stretched LED array grid onto
a plate or between two plates
Inventors: |
WEEKAMP; Johannes;
(Eindhoven, NL) ; SLOB; Cornelis; (Eindhoven,
NL) |
Assignee: |
KONINKLIJKE PHILIPS ELECTRONICS
N.V.
EINDHOVEN
NL
|
Family ID: |
38374150 |
Appl. No.: |
13/101416 |
Filed: |
May 5, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12289281 |
Oct 23, 2008 |
|
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13101416 |
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Current U.S.
Class: |
257/88 ;
257/E27.12; 257/E33.057; 438/28 |
Current CPC
Class: |
F21V 21/002 20130101;
H01L 2924/01047 20130101; H01L 2224/48091 20130101; H01L 2924/01047
20130101; F21Y 2115/10 20160801; H01L 2224/45147 20130101; H01L
2224/45147 20130101; F21S 4/28 20160101; H01L 2924/207 20130101;
H01L 2224/48465 20130101; B21F 45/00 20130101; H01L 2224/45015
20130101; H01L 2224/45015 20130101; F21S 4/15 20160101; H01L 33/62
20130101; F21K 9/90 20130101; H01L 2924/207 20130101; H01L
2924/00014 20130101; H01L 2924/00014 20130101; H01L 2924/00
20130101; H01L 2924/2076 20130101; H01L 2924/0002 20130101 |
Class at
Publication: |
257/88 ; 438/28;
257/E33.057; 257/E27.12 |
International
Class: |
H01L 33/62 20100101
H01L033/62; H01L 27/15 20060101 H01L027/15 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 25, 2006 |
EP |
06113035.7 |
Dec 8, 2006 |
EP |
06125674.9 |
Claims
1-17. (canceled)
18. A method for production of an LED array grid, the method
comprising the steps of: arranging N electrically conducting wires
(W.sub.1-W.sub.N) in parallel, where N is an integer >1, thus
creating an array of wires (W.sub.1-W.sub.N), said array having a
width D perpendicular to a length direction of the wires
(W.sub.1-W.sub.N), arranging LED components to the array of wires
such that each LED component is electrically coupled to at least
two adjacent wires (W.sub.n-W.sub.n+1), stretching the array of
wires such that the width D increases and a gap is formed between
adjacent wires, and arranging the stretched LED array grid onto a
substrate.
19. The method of claim 18, wherein the LED components are arranged
such that the LED components are distributed at regular intervals
after stretching of the grid.
20. The method of claim 19, wherein the LED components are arranged
such that, in a direction perpendicular to the length direction of
the wires (W.sub.1-W.sub.N), the stretched LED array grid comprises
at least one row of LED components bridging every other gap between
adjacent wires.
21. The method of claim 18, wherein the array of wires is formed by
winding a wire in a helical fashion around an assembly drum and
wherein a winding of the array of wires leaves the assembly drum
after the step of arranging each LED component to the two adjacent
wires, thereby creating a cylinder-shaped grid of wires and LED
components.
22. The method of claim 21, further comprising the step of cutting
the wire at least once along each winding of the cylinder-shaped
grid.
23. The method of claim 18, wherein the LED components are soldered
to the wires.
24. The method of claim 18, wherein the substrate comprises at
least one glass plate.
25. The method of claim 18, further comprising the steps of:
providing a substrate comprising a leadframe material, folding the
substrate in order to obtain positions for receiving a wire,
interconnecting LED components by wire bonding or a flip-chip
technique, and over moulding the LED components with a clear.
26. An illumination system comprising a LED array grid manufactured
according to claim 18.
27. The illumination system according to claim 13, wherein the LED
array grid is bonded to the glass plate.
28. The illumination system according to claim 13, wherein the LED
array grid is disposed between two glass plates.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for production of
an illumination system, an illumination system produced with said
method, and a winding device.
TECHNICAL BACKGROUND
[0002] Light emitting diodes (LEDs) have been used as backlight for
displays and illumination panels for some time, where a large
number of low power LEDs are arranged in an array. LEDs are well
suited for this purpose for several reasons. They are, for
instance, durable structures with a long lifetime, which reduces
the maintenance needed. Also, they have a low power consumption and
are operated at lower voltages, which reduces costs of operation
and risks related to high voltage applications. In relation to this
they have an high light output. Prior art techniques include the
arrangement of LEDs on printed circuit boards (PCBs). This is,
however a costly solution, especially when the LEDs are on a large
pitch an larger areas are to be illuminated.
SUMMARY OF THE INVENTION
[0003] In order to provide a LED array that is suitable for the
above and other purposes where a large area illumination is needed
and at the same time solving the drawbacks in prior art solutions
the present invention provides a method for production of a LED
array grid, comprising the steps of: [0004] arranging N
electrically conducting wires (W.sub.1-W.sub.N) in parallel, where
N is an integer >1, thus creating an array of wires, said array
having a width D perpendicular to a length direction of the wires,
[0005] arranging LED components to the array of wires such that
each LED component is electrically coupled to at least two adjacent
wires, [0006] stretching the array of wires such that the width D
increases.
[0007] By using low cost assembly processes on very small printed
circuit boards and a novel design of these boards it is possible to
make the interconnects for large area arrays with wires by a simple
winding/soldering process. The novel design of the PCBs refers to
that the resulting LED components preferably are adapted for use in
the inventive method by the provision of dedicated locations on the
LED components adapted for contact with the wire, e.g. locations in
which the electrical contact is facilitated and/or the wire is kept
in position. Further, the use of a wire instead of a large area
printed circuit board further decreases the cost for the LED array
grid. By using the inventive method it is possible to achieve
several advantages in comparison to known techniques. According to
the method the production steps can be performed in a limited
space, which facilitates operation reduces construction costs,
while the end result can be a large LED array grid with any desired
pitch.
[0008] According to one or more embodiments the LED components are
arranged such that the LED components are regularly distributed
after stretching of the grid and in one or more embodiments the LED
components are arranged such that, in a direction perpendicular to
the length direction of the wires, there is a row of LED component
bridging every other gap between adjacent wires.
[0009] In one or more embodiments adjacent rows of LED components
are shifted such that if a first row bridges every other gap
between adjacent wires starting at a first gap, the adjacent row
bridges every other gap between adjacent wires starting at an
adjacent gap. When stretched this can result in a LED array grid
where the wires forms diamond-shaped openings.
[0010] In one or more embodiments the rows are arranged in row
pairs and wherein adjacent row pairs of LED components are shifted
in such a way that if a first row pair bridges every other gap
between adjacent wires starting at a first gap, the adjacent row
pair bridges every other gap between adjacent wires starting at an
adjacent gap. After stretching this arrangement can result in a LED
array grid with equidistant rows and columns.
[0011] In one or more embodiments the array of wires are formed by
winding a wire in a helical fashion around an assembly drum and
wherein a winding of the array of wires can leave the assembly drum
after the step of securely fixing each LED component to said two
adjacent wires included in the winding is finalized, thus creating
a cylinder shaped grid of wires and LED components. The use of an
assembly drum makes it possible to generate a continuous assemble
process where components are fed in one end and a refined product
is achieved in the other.
[0012] In one or more embodiments the method further comprises the
step of cutting the wire at least once along each winding of the
cylinder shaped grid. This step is beneficial in the cases where a
planar LED array grid is desired.
[0013] The LED components are preferably soldered, glued or similar
to the wires or comprise IDC type fasteners (IDC--insulation
displacement connector) in order to provide a durable LED array
grid and ensure a reliable electrical contact.
[0014] According to one or more embodiments the method further
comprises the steps of: [0015] preparing a leadframe material for a
substrate, [0016] folding the substrate in order to obtain
"snap-lock" positions for a wire, [0017] placing/interconnecting
LEDs by means of wire bonding or flip-chip, [0018] over moulding
the LEDs with a clear compound [0019] back etch carrier substrate,
[0020] dice into components.
[0021] The resulting LED components are suitable for use in the
inventive LED array grid, as well as for other applications.
[0022] The invention also relates to a winder device for production
of a LED array grid, which winder device according to one
embodiment comprises rotatable pins extending essentially in the
same direction and being arranged along a circumference, thus
forming a winding drum, wherein said rotatable pins are provided
with threads adapted to effectively locate an electrically
conducting wire being wound around the drum, thus creating a
parallel array of wires,
[0023] wherein rotation of said pins transports the array of wires
along the length of the pins,
[0024] said device further comprising means for arranging LED
components to the array of wires, and
[0025] means for securely fixing each LED component to said two
adjacent wires.
[0026] The winder device is well suited for production of the
inventive LED array grid.
[0027] In one or more embodiments the winder device further
comprises a gear coupling the rotation of the drum to the rotation
of each of the pins such that one revolution of the drum results in
one revolution of each pin. This feature results in that one "turn"
of the resulting cylindrical LED array grid will be wound of the
drum during each revolution of the drum. This means that the rate
at which the grid is fed off the device equals the rate at which
the wire is fed onto the device, which is beneficial.
DESCRIPTION OF DRAWINGS
[0028] FIG. 1 is a graphical flowchart showing an outline of one
embodiment of the inventive method.
[0029] FIG. 2 is a perspective view illustrating LED components
arranged on a PCB used for a soldered version.
[0030] FIG. 3a-c are perspective views illustrating the production
steps for LED components that are of IDC (insulation displacement
connector) type.
[0031] FIG. 4 is a perspective partial view showing details of a
device performing the inventive method.
[0032] FIG. 5 is a perspective view from behind of the device of
FIG. 4.
[0033] FIG. 6 is a schematic view of an alternative embodiment of
the inventive method.
[0034] FIG. 7 is a perspective view of a LED array grid according
to one embodiment of the invention arranged between two glass
plates.
[0035] FIGS. 8a and 8b are schematic views illustrating the
structure of LED components which are adapted for soldered or glued
wires as interconnect.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0036] FIG. 1 shows the main steps of the inventive method. It
illustrates an example of how LEDs 102 for use in the present
invention can be arranged on a PCB 104, see also FIG. 2. The LEDs
102 can be prepackaged LEDs or naked dyes. In this example the PCB
104 is provided with a specific hole pattern and when the PCB 104
is diced into separate LED components 106 the holes 108 can be
defined such as to provide attachment points used in a soldering
process later on in the inventive method. It is cost efficient to
arrange the LEDs 102 with a low pitch on a PCB 104 and to make as
much use of the PCB material as possible.
[0037] After this preparing step the actual assembly takes place. A
wire 110 is wound around an assembly drum 112, to be described in
more detail later, and the separate LED components 106 are arranged
in specific slots 114 that locates them before the wire 110 is
wound into the holes 108 forming the attachment points. The wire is
generally indicated with 110, while each individual "turn" of the
wire is designated W.sub.n, n=1, 2 etc, W.sub.1 being the first
turn of the wire 110, W.sub.2 the second, and so forth. The
assembly drum 112 rotates so that a feed device, schematically
shown at 116 in FIG. 4, which feed device 116 contains a set of LED
components 106, can be a fixed device in the sense that it does not
need to move in order to position the LED components 106 correctly
in the slots 114. This also means that equipment, such as soldering
devices (not shown), can have a fixed location.
[0038] While the assembly drum 112 rotates, the wire 110 being
wound on the drum 112 will gradually be fed off the drum, which
also will be described later on in relation to FIGS. 4 and 5.
[0039] The assembly process can continue indefinitely or, in
practice, as long as needed. The thus created, cylindrical, LED
array grid is generally cut and unfolded, which is shown as the
next illustrative step in the flow chart of FIG. 1. Finally the LED
array grid is stretched to create a large area LED array grid 100,
the size of which is adapted to its intended use. From FIG. 1 and
the above description it should be clear that a width of the grid,
being a function of the diameter (or the circumference) of the
assembly drum 112, is limited, while the length if the LED array
grid 100 is infinite, at least theoretically. Some processing steps
in order to obtain the final lighting product remains. It should be
mentioned that soldering is only one example of a fastening
technique that could be used. There are alternatives such as laser
welding, ultrasonic techniques, etc.
[0040] Obviously, the arrangement can be the opposite, i.e. the
drum 112 is static while other equipment revolves around it.
Combinations of these two extremes are also anticipated.
[0041] FIG. 2 illustrates a small pitch assembly of LEDs 102 on a
PCB material. The assembly is shown after being diced into
individual LED components 106. It can be noticed how the dicing is
offset so as to transform the holes 108 into suitable soldering
points.
[0042] FIG. 3a-c illustrates a few steps in the construction of
IDC-type LED components 206. It is shown how LEDs 102 are arranged
on a metal substrate 204 or lead frame, after which the substrate
204 is cut or punched into separate LED components 206 (see FIG.
3c). An advantage with the IDC-type LED components 206 is that they
do not have to be soldered onto the wire 100. Also, the wire 100
could be insulated while still permitting the IDC-type LED
components 206 to be fastened and electrically connected to the
wire 100. The use of IDC-type LED components 206 makes the step of
attaching the LED components 206 to the wire 100 a bit more
flexible. The LED components can be arranged in a slot,
corresponding to slot 114 prior to the wire 110 being wound around
the assembly drum 112, but they could equally well be arranged on
the wire 110 after said wire have been wound onto the assembly drum
112.
[0043] FIG. 4 illustrates a detail of the assembly drum 112 during
an assembly process. The drum 112 has a main body 118 which rotates
around an axis A with a predetermined speed. The drum 112 also
comprise rotating pins 120. These pins 120 are driven to rotate,
e.g., by a belt or gears (not shown) as the drum 112 rotates. The
pins 120 are on one end provided with coarse threads 122, as shown
in FIGS. 4 and 5. As the drum 112 rotates a wire 100 is wound onto
the drum 112 and positioned by the threads 122. The rotation of the
pins 120 will, by means of the threads 122, gradually feed the wire
100 off the assembly drum 112. At the same time the rotating pins
120 are the operative part onto which the wire 100 is wound.
Between adjacent pins, on their threaded end, the LED locating
slots 114 are arranged. These serves to, together with the wire
110, locate the LED components 106 until they are fastened to the
wire 110. A component feed device 116 is arranged to position LED
components 106, 206 in the locating slots, after which the
components can be fastened to the wire 110. The rotation of the
drum body 118, the rotation of the rotating pins 120, and the pin
threads 122 are so arranged that the component feed device 116, as
well as the fastening of LED components 106, 206, can take place in
a fixed position, which makes it possible to simplify the equipment
needed for these operations.
[0044] FIG. 5 shows the assembly drum 112 from behind, and also
shows how the LED array grid 100 starts to be fed off the drum.
[0045] The assembly process as described has some advantages
regarding the simplicity of surrounding equipment such as the
component feed and the soldering device. However, the inventive
idea could also be realised in a planar approach, as schematically
shown in FIG. 6, in which the single wound wire 110 and the
assembly drum 112 is replaced by several individual, parallel wires
210 being fed in a plane to a mounting area 212 where LED
components 106, 206 are attached along the length of the wires 210.
The arrow in FIG. 6 indicates the feeding direction. Just like in
the previously mentioned embodiment, the resulting LED array grid
100 can be stretched to a desired length, which obviously is
dependent the distribution of LED components 106, 206 on the LED
array grid. This planar approach has an advantage in that the width
of the final LED array grid potentially is more easy to vary, in
terms of production equipment. From the above description of the
assembly using an assembly drum features not specifically related
to the use of a drum, also can be applied to the planar
approach
[0046] Note that the described and showed distribution of LED
components on the wire grid is given as an example only. The LED
components 106, 206 could equally well be given an alternative
distribution, as long as it would enable suitable stretching
opportunities. An example of an alternative distribution is that
the LED components are placed in alternately in groups of one,
which should be read in the context that the LED components 106,
206 in the drawings are arranged alternately in groups of two.
[0047] The LED array grid that is created with the inventive method
is extremely cost efficient in comparison to a known PCB solution,
i.e. a solution in which a PCB forms the entire area of the array
grid. The cost for one square meter LED array if a PCB is used will
exceed 50 Euro, while the cost for the wire mesh solution is less
than 1 Euro.
[0048] Suitable, but not exclusive applications for the inventive
LED array grid 100 are backlighting for LCD displays, an
alternative to compact fluorescent lamps and sphere lighting like
light emitting walls or windows.
[0049] A novel usage includes the arrangement of the LED array grid
100 on a glass plate, or sandwiched between two glass plates 302,
304 as exemplified in FIG. 7. The space between the glass plates
can be filled with polyvinyl butyral (PVB). The PVB provides for a
strong sandwich structure bonding the glass plates and also reduces
reflections thanks to its optical properties. As conductor for the
electrical current, a transparent layer on one of the glass plates
can be used, such as indium tin oxide (generally called ITO) or
fluor doped tin oxide (generally called FTO). The LEDs are bonded
to this coated glass, e.g. with conductive adhesive or solder.
However, both ITO and FTO possess a high sheet resistance which
limits the power of the LEDs, furthermore it is not easy to make a
reliable interconnect between LEDs and layers of ITO or FTO, which
is why the use of an LED array grid 100 is advantageous from this
perspective.
[0050] The LED array grids can also be bonded to the glass plate by
means of self-bonding wires. Such wires are coated with a first
strong isolating layer--this layer has a high melting point
(>300.degree. C.)--and a second isolation layer with a lower
melting point (<200.degree. C.). This second layer is in case of
making coils used for bonding the wires within a coil to make it
rigid. The heat can be applied by a current through the wires or by
placing the coil in an oven, it is also possible to use a solvent
to obtain adhesion. In cases where the LEDs are thinner than the
wires the same bonding principle can be used by applying
temperature and pressure on the glass-LED sandwich structure.
[0051] The use of wires, e.g. a 0.3 mm diameter copper wire as
compared to a transparent layer of ITO or FTO gives huge advantages
in terms of efficiency, mainly coupled to the much higher
resistance per length unit for said transparent layers.
[0052] FIGS. 8a and 8b are schematic views exemplifying a LED
component construction, or LED package, which is particularly
suitable for the purposes of the inventive LED array grid 100, and
also the sandwich construction described above. The method for
producing the LED package involves the steps of: [0053] preparing a
leadframe material 204 for a substrate, [0054] folding the
substrate in order to obtain various "snap-lock" positions 208 for
a wire 210 which will be attached in use, [0055]
placing/interconnecting LEDs 202 by means of wire bonding or
flip-chip, [0056] over moulding with a clear compound 224 [0057]
back etch carrier substrate, [0058] dice into components 306.
[0059] The above construction can also comprise a heatsink arranged
in thermal contact with the LEDs.
[0060] It should be noted that each wire could if needed consist of
two, or more, conductors, as illustrated in FIGS. 8a-b.
* * * * *