U.S. patent application number 14/118818 was filed with the patent office on 2014-07-17 for method of arranging a multiplicity of leds in packaging units, and packaging unit comprising a multiplicity of leds.
This patent application is currently assigned to OSRAM Opto Semiconductors GmbH. The applicant listed for this patent is Felix Michel, Roland Schulz, Alexander Wilm. Invention is credited to Felix Michel, Roland Schulz, Alexander Wilm.
Application Number | 20140197429 14/118818 |
Document ID | / |
Family ID | 46177408 |
Filed Date | 2014-07-17 |
United States Patent
Application |
20140197429 |
Kind Code |
A1 |
Wilm; Alexander ; et
al. |
July 17, 2014 |
METHOD OF ARRANGING A MULTIPLICITY OF LEDS IN PACKAGING UNITS, AND
PACKAGING UNIT COMPRISING A MULTIPLICITY OF LEDS
Abstract
A method of arranging a multiplicity of LEDs in packaging units
includes defining a desired range for at least one photometric
measurement variable for each of the packaging units; selecting an
LED from the multiplicity of LEDs not yet arranged in one of the
packaging units; measuring the at least one photometric measurement
variable for the selected LED; equipping one of the packaging units
containing fewer than N-1 LEDs with the selected LED; storing a
measured value and a position of the selected LED in the packaging
unit in a memory; repeating until the packaging units are equipped
with N-1 LEDs; repeating and calculating the average value of the
photometric measurement variable, equipping a packaging unit for
which the calculated average value of the variable lies in a
defined range with the selected LED; and storing the measured value
and the position of the selected LED.
Inventors: |
Wilm; Alexander;
(Regensburg, DE) ; Schulz; Roland; (Regensburg,
DE) ; Michel; Felix; (Munchen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Wilm; Alexander
Schulz; Roland
Michel; Felix |
Regensburg
Regensburg
Munchen |
|
DE
DE
DE |
|
|
Assignee: |
OSRAM Opto Semiconductors
GmbH
Regensburg
DE
|
Family ID: |
46177408 |
Appl. No.: |
14/118818 |
Filed: |
May 16, 2012 |
PCT Filed: |
May 16, 2012 |
PCT NO: |
PCT/EP2012/059171 |
371 Date: |
January 30, 2014 |
Current U.S.
Class: |
257/88 ;
438/15 |
Current CPC
Class: |
H01L 27/156 20130101;
H01L 22/26 20130101; H01L 22/24 20130101; H01L 25/0753 20130101;
H01L 33/0095 20130101; F21K 9/90 20130101; H01L 33/48 20130101;
H01L 2933/0033 20130101 |
Class at
Publication: |
257/88 ;
438/15 |
International
Class: |
H01L 21/66 20060101
H01L021/66; H01L 27/15 20060101 H01L027/15 |
Foreign Application Data
Date |
Code |
Application Number |
May 31, 2011 |
DE |
10 2011 103 752.0 |
Claims
1-15. (canceled)
16. A method of arranging a multiplicity of LEDs in packaging
units, comprising: a) defining a desired value range for at least
one photometric measurement variable for each of the packaging
units, wherein an average value of the photometric measurement
variable for a fixed number of N.gtoreq.3 successive LEDs in the
packaging units is intended to lie in the desired value range; b)
providing the multiplicity of LEDs and the packaging units; c)
selecting an LED from the multiplicity of LEDs which is not yet
arranged in one of the packaging units; d) measuring the at least
one photometric measurement variable for the selected LED; e)
equipping one of the packaging units, containing fewer than N-1
LEDs with the selected LED, wherein the LEDs are strung together in
the packaging unit in the equipping order; f) storing a measured
value of the at least one photometric measurement variable and a
position of the selected LED in the packaging unit in a data
memory; g) repeating c) to f), until all of the packaging units are
equipped with N-1 LEDs; h) repeating c) and d) and calculating the
average value of the at least one photometric measurement variable,
which respectively results for the N-1 LEDs last arranged in the
packaging unit and the selected LED, wherein the calculation is
carried out for all of the packaging units; i) equipping a
packaging unit for which the calculated average value of the at
least one photometric measurement variable lies in a defined
desired value range with the selected LED, wherein the selected LED
is arranged in the packaging unit such that it directly follows the
LED last arranged in the packaging unit; or sorting out the
selected LED if the calculated average value of the photometric
measurement variable does not lie in the defined desired value
range for any of the packaging units; j) storing the measured value
of the at least one photometric measurement variable and the
position of the selected LED in the packaging unit in a data
memory; and k) repeating h) to j), until the packaging units are
equipped with a desired total number of LEDs.
17. The method according to claim 16, wherein the at least one
photometric measurement variable is brightness and/or locus.
18. The method according to claim 16, wherein the number of
packaging units is at least 4.
19. The method according to claim 16, wherein the packaging units
are rolls.
20. The method according to claim 16, wherein the packaging units
are identified with the number N of successive LEDs for which the
average value of the at least one photometric measurement variable
lies in the desired value range.
21. The method according to claim 16, wherein the packaging units
are identified with the at least one photometric measurement
variable and the desired value range.
22. The method according to claim 16, wherein the number N is 3 to
25.
23. The method according to claim 16, wherein the total number of
the LEDs arranged in the packaging units is greater than the number
N at least by a factor of 20.
24. The method according to claim 16, wherein the total number of
the LEDs arranged in the packaging units is at least 500.
25. A packaging unit comprising a multiplicity of LEDs, wherein:
the LEDs are arranged in the packaging unit in an order; an average
value of at least one photometric measurement variable for a number
of N.gtoreq.3 successive LEDs removed at an arbitrary location of
the packaging unit lies in a desired value range for the at least
one photometric measurement variable; the packaging unit is
identified with the number N; and the total number of the LEDs
arranged in the packaging unit is greater than the number N at
least by a factor of 20.
26. The packaging unit according to claim 25, wherein the at least
one photometric measurement variable is brightness and/or color
locus.
27. The packaging unit according to claim 25, wherein the packaging
unit is a roll.
28. The packaging unit according to claim 25, wherein the number N
is 3 to 25.
29. The packaging unit according to claim 25, wherein the total
number of the LEDs arranged in the packaging units is at least
500.
30. The packaging unit according to claim 25, wherein the packaging
unit is identified with the at least one photometric measurement
variable and the desired value range.
Description
TECHNICAL FIELD
[0001] This disclosure relates to a method of arranging LEDs in
packaging units, and to a packaging unit comprising a multiplicity
of LEDs.
BACKGROUND
[0002] On account of their high efficiency, LEDs are increasingly
being used in LED lamps for general lighting or in automobile
headlights. It is often the case that a plurality of LED lamps are
operated alongside one another, wherein the individual LED lamps
can each contain a plurality of LEDs.
[0003] For different LED lamps arranged alongside one another offer
a homogeneous appearance with regard to their brightness and/or
their color, it is desirable for radiation emitted by the different
LED lamps to have the same brightness and/or the same color locus
in each case. However, during the manufacture of LEDs it cannot be
ruled out that small brightness or color deviations of the
individual LEDs occur, particularly in the case of LEDs from
different production series. For this reason, the LED manufacturer
often groups LEDs prior to delivery (so-called "binning"), wherein
a group of LEDs (the so-called "bin") is distinguished, for
example, by the fact that all the LEDs in this group have the same
brightness and/or the same color locus. If only LEDs from a single
group are used during production of LED lamps, it is ensured that
all luminaires equipped with the LEDs have the same brightness
and/or the same color locus. In this case, however, it is necessary
for the customer of the LED manufacturer, which customer processes
the individual LEDs further to form LED lamps, in each case to use
only LEDs from the same LED group such that all the luminaires of
different production series have the same brightness and/or the
same color locus. Alternatively, it would also be conceivable for a
luminaire manufacturer, in equipping an LED lamp, to select in a
targeted manner a plurality of LEDs from different LED groups
having different brightnesses and/or color loci such that the
luminaire containing a plurality of LEDs has overall the desired
values for the brightness and/or the color locus. This would have
the advantage that the luminaire manufacturer could use LEDs from
groups having different brightnesses and/or color loci, but on the
other hand leads to an increased production outlay since LEDs from
different packaging units would have to be used to equip an
individual LED lamp.
[0004] It could therefore be helpful to provide a method of
arranging LEDs in a packaging unit, which method achieves the
effect that an LED component having a predetermined number of LEDs
fulfils a desired value range for at least one photometric
measurement variable, wherein the outlay to equip the LED component
with LEDs from the packaging unit is low. Furthermore, it could be
helpful to provide an advantageous packaging unit comprising a
multiplicity of LEDs.
SUMMARY
[0005] We provide a method for arranging a multiplicity of LEDs in
packaging units, including:
[0006] a) defining a desired value range for at least one
photometric measurement variable for each of the packaging units,
wherein an average value of the photometric measurement variable
for a fixed number of N.gtoreq.3 successive LEDs in the packaging
units is intended to lie in the desired value range;
[0007] b) providing the multiplicity of LEDs and the packaging
units;
[0008] c) selecting an LED from the multiplicity of LEDs which is
not yet arranged in one of the packaging units;
[0009] d) measuring the at least one photometric measurement
variable for the selected LED;
[0010] e) equipping one of the packaging units, containing fewer
than N-1 LEDs with the selected LED, wherein the LEDs are strung
together in the packaging unit in the equipping order;
[0011] f) storing a measured value of the at least one photometric
measurement variable and a position of the selected LED in the
packaging unit in a data memory;
[0012] g) repeating c) to f), until all of the packaging units are
equipped with N-1 LEDs;
[0013] h) repeating c) and d) and calculating the average value of
the at least one photometric measurement variable, which
respectively results for the N-1 LEDs last arranged in the
packaging unit and the selected LED, wherein the calculation is
carried out for all of the packaging units;
[0014] i) equipping a packaging unit for which the calculated
average value of the at least one photometric measurement variable
lies in a defined desired value range with the selected LED,
wherein the selected LED is arranged in the packaging unit such
that it directly follows the LED last arranged in the packaging
unit; or sorting out the selected LED if the calculated average
value of the photometric measurement variable does not lie in the
defined desired value range for any of the packaging units;
[0015] j) storing the measured value of the at least one
photometric measurement variable and the position of the selected
LED in the packaging unit in a data memory; and
[0016] k) repeating h) to j), until the packaging units are
equipped with a desired total number of LEDs.
[0017] We also provide a packaging unit including a multiplicity of
LEDs, wherein: [0018] the LEDs are arranged in the packaging unit
in an order; [0019] an average value of at least one photometric
measurement variable for a number of N.gtoreq.3 successive LEDs
removed at an arbitrary location of the packaging unit lies in a
desired value range for the at least one photometric measurement
variable; [0020] the packaging unit is identified with the number
N; and [0021] the total number of the LEDs arranged in the
packaging unit is greater than the number N at least by a factor of
20.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIGS. 1 to 8 show an illustration of an example of the
method of arranging a multiplicity of LEDs in packaging units on
the basis of schematically illustrated intermediate steps.
[0023] FIG. 9 shows a schematic illustration of packaging units
each comprising a multiplicity of LEDs.
DETAILED DESCRIPTION
[0024] We provide a method by which a multiplicity of LEDs are
arranged in a plurality of packaging units.
[0025] Thus, a first step may involve defining a desired value
range for at least one photometric measurement variable for each of
the packaging units, wherein the average value of the photometric
measurement variable for a fixed number of N.gtoreq.3 successive
LEDs in the packaging units is intended to lie in the desired value
range.
[0026] In one configuration, the desired value range and the fixed
number N of successive LEDs for which the average value of the
photometric measurement variable is intended to lie in the desired
value range are identical for the plurality of packaging units. By
way of example, it can be provided that in each case four
successive LEDs intended to be removed from one of the packaging
units are intended to have an average value of the photometric
measurement variable which is intended to lie in the desired value
range. In this case, therefore, N=4 for all of the packaging
units.
[0027] Alternatively, however, it is also possible for the
plurality of packaging units to differ in terms of the desired
value range and/or the fixed number N of successive LEDs for which
the average value of the at least one photometric measurement
variable lies in the desired value range. By way of example, it can
be provided that three packaging units are equipped simultaneously,
wherein the average value of the photometric measurement variable
in the first packaging unit for N.sub.1=3 successive LEDs is
intended to lie in the desired value range. For the second
packaging unit, the average value of the photometric measurement
variable, for example, for N.sub.2=5 successive LEDs is intended to
lie in the desired value range, and for N.sub.3=7 successive LEDs
for the third packaging unit. The number N of successive LEDs in
the packaging unit for which the average value of the photometric
measurement variable is intended to lie in the desired value range
is preferably defined according to the number of LEDs which the
customer of the LED manufacturer removes from the packaging units
for the purpose of equipping optoelectronic components. If, with
the LEDs from a packaging unit, for example, optoelectronic
components are in each case intended to be equipped with 5 LEDs,
N=5 is defined for the packaging unit. In this case, the packaging
unit is equipped by the method described below such that 5
successive LEDs removed from the packaging unit at an arbitrary
location in the order of their arrangement respectively have an
average value of the photometric measurement variable which lies in
the predetermined desired value range.
[0028] In the method, the multiplicity of LEDs are provided, for
example, in a supply container from which the LEDs can preferably
be automatically removed individually. The multiplicity of LEDs can
comprise, for example, more than 1000 or even more than 10000 LEDs.
In particular, the multiplicity of LEDs can be a production series
of LEDs of identical type which are intended to be arranged in
packaging units prior to delivery to a customer of the LED
manufacturer. Furthermore, the plurality of packaging units in
which the LEDs are intended to be arranged are provided.
[0029] An LED which is not yet arranged in one of the packaging
units may be selected from the multiplicity of LEDs. The selected
LED is, for example, an arbitrary LED removed from the supply
container.
[0030] Afterwards, the at least one photometric measurement
variable is measured for the selected LED.
[0031] In a further step, one of the packaging units which still
contains fewer than N-1 LEDs is equipped with the selected LED. The
LEDs are strung together in the packaging units in each case in the
equipping order. In other words, the LEDs are arranged sequentially
in the packaging units, wherein the LED first arranged in the
packaging unit is arranged at a first location, the LED arranged as
second in the packaging unit is arranged at a second location, the
LED arranged as third is arranged at a third location, and so on.
The LEDs can therefore be removed again from the packaging unit in
the order or the opposite order in which the packaging unit was
equipped with the LEDs.
[0032] The measured value of the at least one photometric
measurement variable and the position of the selected LED in the
packaging unit are advantageously stored in a data memory.
[0033] The steps of selecting an LED, measuring the at least one
photometric measurement variable of the selected LED, equipping one
of the packaging units with the selected LED and storing the
measured value and the position of the selected LED are
subsequently repeated until all of the packaging units are equipped
with N-1 LEDs.
[0034] Afterwards a further LED not yet arranged in one of the
packaging units may be selected, and the at least one photometric
measurement variable may be measured for the selected LED.
[0035] This is followed by calculating the average value of the at
least one photometric measurement variable which respectively
results for the N-1 LEDs last arranged in the packaging unit and
the selected LED, wherein this calculation is preferably carried
out for all of the packaging units. For this purpose, the measured
values of the N-1 LEDs last arranged in the respective packaging
unit are read out from the data memory. A check is made to
determine whether, for at least one packaging unit, the number of N
LEDs, which results from addition of the selected LED to the N-1
LEDs last arranged in the packaging unit, has an average value of
the at least one photometric measurement variable that lies in the
defined desired value range.
[0036] In a further step, a packaging unit is advantageously
equipped with the selected LED for which the average value of the
at least one photometric measurement variable calculated in this
way lies in the previously defined desired value range. In this
way, it is ensured that the N LEDs last arranged in the packaging
unit have an average value of the photometric measurement variable
which lies in the defined desired value range. In this method step,
the selected LED is arranged in the packaging unit such that it
directly follows the LED last arranged in the packaging unit. The
LEDs are therefore strung together in the equipping order.
[0037] If the average value of the at least one photometric
measurement variable for the N-1 LEDs last arranged in the
packaging used and the selected LED does not lie in the previously
defined desired value range for any of the packaging units, the
selected LED cannot be assigned to any of the packaging units, and
is sorted out. The LEDs sorted out are preferably stored in an
intermediate store or fed to the supply container again since they
can possibly be assigned to one of the packaging units in a later
method step.
[0038] The measured value of the at least one photometric
measurement variable and the position of the selected LED in the
packaging unit are advantageously stored in the data memory.
[0039] The steps of selecting an LED, calculating the average value
of the photometric measurement variable, equipping a packaging unit
with the selected LED and storing the measured value and the
position, or if appropriate sorting out the LED, are subsequently
repeated until the packaging units are equipped with the desired
total number of LEDs.
[0040] The packaging units are advantageously equipped with LEDs
such that in each case a number of exactly N LEDs have an average
value of the at least one photometric measurement variable which
lies in the previously defined desired value range. Therefore, if
exactly N successive LEDs are removed from the packaging unit, it
is ensured that the average value of the photometric measurement
variable for this number of N LEDs lies in the predetermined
desired value range. When removing the LEDs from the packaging
unit, it is not important from which location of the packaging unit
the first LED of the sequence is removed. In particular, the
average value of the at least one photometric measurement variable
of a sequence of exactly N successive LEDs lies in the
predetermined desired value range even when the LEDs are removed
from the packaging unit in the opposite order to the equipping
order. Furthermore, the average value of integer multiples of the
number of N LEDs also lies in the desired value range. A packaging
unit which is identified with the number N and is provided to equip
components with N LEDs can therefore also be used to equip
components with 2N LEDs, 3N LEDs and so on.
[0041] The fact that in each case exactly N successive LEDs, on
account of the method described here for arrangement in the
packaging unit, definitely have an average value of the photometric
measurement variable in the desired value range does not, of
course, rule out the fact that this can also be the case for a
different number of LEDs in the packaging unit.
[0042] The method described herein to arrange LEDs in packaging
units is advantageous particularly when the packaging units are
provided to equip optoelectronic components each having a fixed
number of N LEDs, wherein the N LEDs on average have to comply with
a desired value for a photometric measurement variable. In
particular, the arrangement of LEDs as described herein is
advantageous in packaging units to equip components in which at
least slight differences in the at least one photometric
measurement variable of individual LEDs can be afforded tolerance
if the average value of the N LEDs fulfils the desired value of the
at least one photometric measurement variable. This is the case,
for example, in optoelectronic components in which the plurality of
LEDs, for example, on account of a light-diffusing cover, are not
individually perceptible or are individually perceptible only with
difficulty.
[0043] Advantageously, the at least one photometric measurement
variable is the brightness of the LEDs. In this case, the LEDs are
advantageously arranged in the packaging units in such a way that a
sequence of N successive LEDs in each case has on average a
brightness which lies in the defined desired value range.
[0044] Further, the at least one photometric measurement variable
may be the color locus of the LEDs. The color locus can be
specified, in particular, by the coordinates C.sub.x and C.sub.y in
the CIE chromaticity diagram. In this configuration, the average
value of the color coordinates C.sub.x, C.sub.y of N successive
LEDs in the packaging units lies in each case in the defined
desired value range. Consequently, this fixed number of N LEDs has
the same color impression in each case.
[0045] It is possible for a plurality of photometric measurement
variables to be used for the arrangement of the LEDs in the method.
Particularly preferably, the photometric measurement variables are
both the brightness and the color locus of the LEDs. In this
configuration, therefore, the LEDs are arranged in the packaging
units such that, for a predetermined number of N LEDs, both the
average value of the brightness and the average values of the color
coordinates lie in predetermined desired value ranges. In this way,
it is ensured that a fixed number of N successive LEDs meet the
requirements in respect of a predetermined brightness and a
predetermined color locus.
[0046] As an alternative and/or in addition to the brightness
and/or the locus, it is also possible to use another photometric
measurement variable in the method to arrange the LEDs in the
packaging units in a targeted manner. By way of example, the
photometric measurement variable can be the color rendering index
CRI or the wavelength .lamda..sub.max of the intensity maximum of
the LED. Furthermore, it is also possible to use, in addition to
the at least one photometric measurement variable, an electrical
measurement variable to arrange the LEDs in the packaging unit. The
electrical measurement variable can be, for example, the forward
voltage U.sub.f of the LEDs.
[0047] In the method, the number of packaging units is preferably
at least four. By way of example, four to ten packaging units can
be equipped simultaneously.
[0048] The packaging units of the LEDs can be, in particular,
rolls. The LEDs are preferably fixed on a tape on the roll such
that they can easily be removed from the roll. The LEDs can be
removed from the roll in a simple manner in the order in which the
roll was equipped with the LEDs or in the opposite order with
respect thereto.
[0049] Preferably, the packaging units are identified with the
number N of successive LEDs for which the average value of the at
least one photometric measurement variable lies in the desired
value range. A customer of the LED manufacturer, which customer
uses the packaging units for equipping optoelectronic components,
can therefore infer from the packaging unit what number N of
successive LEDs have an average value of the at least one
photometric measurement variable which lies in the desired value
range. To equip optoelectronic components each having a number of N
LEDs, it is therefore possible to select a packaging unit
identified with the value N.
[0050] Preferably, the packaging units are identified with the at
least one photometric measurement variable and the associated
desired value range.
[0051] The number N of LEDs for which the average value of the at
least one photometric measurement variable lies in the desired
value range is preferably 3 to 25, particularly preferably 3 to
15.
[0052] The total number of the LEDs arranged in the packaging units
is advantageously significantly greater than the number N.
Preferably, the total number of the LEDs arranged in the packaging
units is greater than the number N at least by a factor of 20, a
factor of 100 or even a factor of 500.
[0053] The total number of the LEDs arranged in the packaging units
is advantageously at least 500 in each case. Preferably, the total
number of the LEDs arranged in the packaging units is in each case
at least 1000 or even at least 5000. By way of example, the
packaging units can contain 500 to 20000 LEDs.
[0054] Furthermore, a packaging unit comprising a multiplicity of
LEDs is specified in which the LEDs were arranged by the
advantageous methods described herein.
[0055] Preferably, the packaging unit comprises a multiplicity of
LEDs, wherein the LEDs are arranged in an order in the packaging
unit. The average value of at least one photometric measurement
variable for a number of N.gtoreq.3 successive LEDs, removed at an
arbitrary location of the packaging unit lies in a desired value
range for the at least one photometric measurement variable,
wherein the packaging unit is identified with the number N. The
total number of the LEDs arranged in the packaging unit is
advantageously greater than the number N at least by a factor of
20.
[0056] Further advantageous configurations of the packaging unit
can be inferred from the description of the methods.
[0057] The methods of arranging a multiplicity of LEDs in packaging
units and the packaging unit are explained in greater detail below
on the basis of examples in association with FIGS. 1 to 9.
[0058] Identical or identically acting constituent parts are in
each case provided with the same reference symbols in the figures.
The illustrated constituent parts and also the size relationships
of the constituent parts among one another should not be regarded
as true to scale.
[0059] With the methods described herein, a multiplicity of LEDs,
for example, a production series produced by an LED manufacturer,
are packaged in packaging units to be delivered to a customer, for
example.
[0060] As illustrated in FIG. 1, the packaging units can be rolls
R.sub.1, R.sub.2, R.sub.3, for example. The rolls each have a tape
1 on which the LEDs can be fixed. To simplify the illustration, the
method is illustrated on the basis of an example comprising three
packaging units R.sub.1, R.sub.2, R.sub.3. In the methods, however,
it is also possible to use more packaging units, preferably at
least four packaging units being used.
[0061] In the methods, it is provided that, in each of the M
packaging units, where M is the number of packaging units, a fixed
number N.sub.m (m=1 to M) of successive LEDs have an average value
of at least one photometric measurement variable which lies in a
predetermined desired value range.
[0062] The number N.sub.m can be different for the packaging units
which are equipped simultaneously. By way of example, in the case
of the exemplary embodiment illustrated in FIG. 1, a first
packaging unit R.sub.1, for which N.sub.1=3 is defined, a second
packaging unit R.sub.2, for which N.sub.2=4 is defined, and a third
packaging unit R.sub.3, for which N.sub.3=6 is defined, are
simultaneously equipped with LEDs. The number N.sub.m can therefore
be determined separately for all of the packaging units m=1 to M.
Alternatively, it would also be possible for N.sub.m to be
identical for all of the packaging units.
[0063] Furthermore, a desired value range for at least one
photometric measurement variable is defined for each of the
packaging units R.sub.1, R.sub.2, R.sub.3 which desired value range
is intended to be fulfilled by the average value of the respective
N.sub.m LEDs. The photometric measurement variable can be, in
particular, the brightness .PHI.. Advantageously, an interval
[.PHI..sub.min, .PHI..sub.max].sub.m for m=1 to M as desired value
range is defined for each of the packaging units, where
.PHI..sub.min is the permissible minimum brightness and
.PHI..sub.max is the permissible maximum brightness. It is possible
for the desired value range to be identical for all of the
packaging units. Alternatively, however, it is also possible to
define different desired value ranges for the packaging units.
[0064] Advantageously, one or a plurality of further photometric
measurement variables may be used to arrange the LEDs in the
packaging units. In addition or as an alternative to the
brightness, in particular the color locus of the LEDs can be used
as the photometric measurement variable. The color locus of an LED
can be specified, for example, by the color coordinates C.sub.x and
C.sub.y in the CIE chromaticity diagram. In the example described
here, advantageously both the brightness .PHI. and the color
coordinates C.sub.x, C.sub.y are used as photometric measurement
variables for the arrangement of the LEDs in the packaging units.
In the same way as for the brightness .PHI., a desired value range
[C.sub.x,min, C.sub.x,max].sub.m and [C.sub.y,min,
C.sub.y,max].sub.m for m=1 to M is respectively defined for the
color coordinates C.sub.x and C.sub.y as well. The desired value
ranges for the color coordinates can be identical for all of the
packaging units or have different values. The defined numbers
N.sub.m and the desired value ranges are advantageously stored in a
data memory 6.
[0065] As illustrated in FIG. 2, the multiplicity of LEDs 2
intended to be arranged in packaging units are provided in a supply
container 3, for example, from which the LEDs 2 can be individually
removed. In the method, the LEDs 2 are successively removed from
the supply container 3 and distributed among the plurality of
packaging units.
[0066] Afterwards, as illustrated schematically in FIG. 3, the at
least one photometric measurement variable is measured for a
selected LED 2. For this purpose, the radiation 4 emitted by the
LED 2 is measured, for example, by a spectral photometer 5 and/or a
photodiode. In the example described here, the brightness .PHI. and
the color coordinates C.sub.x, C.sub.y of the LED 2 are measured.
Alternatively, however, it would also be possible for a different
photometric measurement variable to be measured, for example, the
wavelength .lamda..sub.max of the intensity maximum and/or the
color rendering index (CRI). Furthermore, it is also possible for
an electrical measurement variable of the LED 2, for example, the
forward voltage U.sub.f, to be measured in addition to the at least
one photometric measurement variable. The measured value of the at
least one photometric measurement variable is stored in a data
memory. In the example illustrated here, therefore, the brightness
.PHI. and the color coordinates C.sub.x, C.sub.y for the selected
LED 2 are stored in a data memory 6.
[0067] In a further method step illustrated schematically in FIG.
4, the selected LED 2 is assigned to one of the packaging units
R.sub.1, R.sub.2, R.sub.3. First, each of the packaging units is
equipped with LEDs until the packaging units R.sub.1, R.sub.2,
R.sub.3 each comprise N.sub.m-1 LEDs. That is to say that, first,
the number of LEDs arranged in each of the packaging units is such
that the packaging units each have one LED fewer than the
previously defined number N.sub.m of successive LEDs which are
intended to have, in the packaging unit, an average value of the at
least one photometric measurement variable which lies in the
defined desired value range. As illustrated in FIG. 4, the first
selected LED 2 is arranged, for example, as first LED on the roll
R.sub.1.
[0068] After arrangement of the LED 2 at a first location of the
roll R.sub.1, the position of the LED 2 and the associated
photometric measurement variables .PHI., C.sub.x, C.sub.y are
advantageously stored in the data memory 6. The position is noted
as P.sub.m,k, for example, where m indicates the number of the
packaging unit and k indicates the number of the LED 2 in the
packaging unit. The first LED of the first packaging unit therefore
has the position P.sub.1,1. Furthermore, the fact that a number of
z.sub.1=1 LEDs is now arranged in the packaging unit R.sub.1 is
stored in the data memory 6.
[0069] In the same way, further LEDs 2 are successively removed
from the supply container, the photometric measurement variables
are measured and the LEDs are assigned to the packaging units
R.sub.1, R.sub.2, R.sub.3. Until the number N.sub.m-1 is reached in
each of the packaging units R.sub.1, R.sub.2, R.sub.3, the
assignment of the respectively selected LED 2 to one of the
packaging units does not have to be effected according to a fixed
rule. Only the condition that for the time being none of the
packaging units is equipped with more than N.sub.m-1 LEDs has to
continue to be fulfilled. Consequently, the packaging units
R.sub.1, R.sub.2, R.sub.3 can be equipped with LEDs up to this
number of LEDs 2 in the packaging units, for example, successively
or according to the random principle. It is also possible, however,
for a selection in respect of which of the packaging units R.sub.1,
R.sub.2, R.sub.3 is assigned the respective selected LED 2 already
to be effected on the basis of the measured photometric measurement
variables.
[0070] FIG. 5 schematically illustrates an intermediate step of the
method in which the first packaging unit R.sub.1 has already been
equipped with two LEDs and the second packaging unit R.sub.2 has
been equipped with three LEDs. Since the value N.sub.1=3 was
defined for the first packaging unit R.sub.1, the first packaging
unit R.sub.1 has already been equipped with N.sub.1-1=2 LEDs. Since
the value N.sub.2=4 was defined for the second packaging unit
R.sub.2, the second packaging unit R.sub.2, too, has already been
equipped with N.sub.2-1=3 LEDs. Consequently, the selected LED 2 is
arranged in the third packaging unit R.sub.3, which contains only
one LED prior to being equipped with the additional LED 2, such
that the number of LEDs in the third packaging unit R.sub.3 is
still less than N.sub.3-1=5. After the arrangement of the selected
LED 2 at the second location of the packaging unit R.sub.3, the
photometric measured values .PHI., C.sub.x, C.sub.y of the LED 2
are assigned to the position P.sub.3,2 of the LED 2 and these
values and also the number z.sub.3=2 of the LEDs in the third
packaging unit R.sub.3 are stored in the data memory 6.
[0071] FIG. 6 illustrates an intermediate step of the method in
which the packaging units R.sub.1, R.sub.2, R.sub.3 have already
been equipped respectively with N.sub.m-1 LEDs. The assignment of a
further selected LED 2, for which the brightness .PHI. and the
color coordinates C.sub.x, C.sub.y were measured, to one of the
packaging units R.sub.1, R.sub.2, R.sub.3 is then effected such
that the average value of the photometric measurement variables
which would result if the additional LED 2 were added to the
N.sub.m-1 LEDs already present is first calculated for all of the
packaging units. The calculated average values of the photometric
measurement variables are then compared to the desired value ranges
previously defined for the packaging units. Therefore, for each
packaging unit a check is made to determine whether the average
value
.PHI. avg = 1 N m k = z m - N m + 1 k = z m + 1 .PHI. k
##EQU00001##
lies in the desired value range [.PHI..sub.min,
.PHI..sub.max].sub.m defined for the packaging unit. In the same
way, a check is made to determine whether the average values
C x , avg = 1 N m k = z m - N m + 1 k = z m + 1 C x , k and C y ,
avg = 1 N m k = z m - N m + 1 k = z m + 1 C y , k ##EQU00002##
lie in the previously defined desired value ranges [C.sub.x,min,
C.sub.x,max].sub.m and [C.sub.y,min, C.sub.y,max].sub.m.
[0072] If the calculated average values for one of the m=1 to M
packaging units lie in the previously defined desired value ranges,
the selected LED is arranged as the next LED in the packaging unit.
In the example in FIG. 6, this is the case, for example, for the
second packaging unit R.sub.2 such that the selected LED 2 is
arranged as the fourth LED in the second packaging unit R.sub.2.
The first four LEDs now arranged in the second packaging unit
R.sub.2 therefore fulfil the condition that the average values of
the photometric measurement variables .PHI..sub.avg, C.sub.x,avg
and C.sub.y,avg lie in the desired value ranges defined for said
packaging unit. After the LED 2 has been arranged as the fourth LED
in the second packaging unit R.sub.2, the position P.sub.2,4 with
the associated photometric measurement variables .PHI., C.sub.x,
C.sub.y and the updated number z.sub.2=4 LEDs in the second
packaging unit R.sub.2 are stored in the data memory 6.
[0073] If, for the selected LED 2, the calculated average values of
the photometric measurement variables do not lie in the previously
defined desired value ranges for any of the packaging units
R.sub.1, R.sub.2, R.sub.3, the selected LED 2 can be stored in an
intermediate store 7, for example, such that it can possibly be
assigned to one of the packaging units R.sub.1, R.sub.2, R.sub.3 at
a later point in time. Furthermore, the case can also occur in
which the calculated average values of the photometric measurement
variables lie in the defined desired value ranges for a plurality
of packaging units. In this case, therefore, it would be possible
to assign the selected LED 2 to a plurality of packaging units. In
this case, the assignment of the selected LED 2 to one of the
suitable packaging units can be effected according to the random
principle or according to a previously defined priority. By way of
example, it can be defined beforehand that the selected LED 2 is in
this case assigned to that packaging unit which still has the
smallest number of LEDs.
[0074] The LEDs 2 subsequently selected from the supply container
are assigned to the packaging units R.sub.1, R.sub.2, R.sub.3 in
the same way, wherein in each case the N.sub.m-1 LEDs last arranged
in the respective packaging unit and the respectively selected LED
2 are used for the calculation of the average values of the
photometric measurement variables. FIG. 7 illustrates e.g. an
intermediate step in which, prior to the addition of the selected
LED 2, the first packaging unit R.sub.1 has been equipped with
eight LEDs, the second packaging unit R.sub.2 has been equipped
with seven LEDs and the third packaging unit R.sub.3 has been
equipped with nine LEDs. For the calculation of the average value
of the photometric measurement variables, the two N.sub.1-1=2 LEDs
last added, that is to say the seventh and eighth LEDs, and the
selected LED 2 are then used in the case of the first packaging
unit. In the case of the second packaging unit, the N.sub.2-1=3
LEDs last arranged in the packaging unit, that is to say the fifth,
sixth and seventh LEDs, and the selected LED 2 are used for the
calculation. In the case of the third packaging unit, the
N.sub.3-1=5 LEDs last arranged in said packaging unit, that is to
say the fifth, sixth, seventh, eighth and ninth LEDs, and the
selected LED 2 are used. During the calculation it emerges, for
example, that the selected LED 2 in combination with the five LEDs
last arranged in the third packaging unit R.sub.3 has average
values of the photometric measurement variables which lie in the
previously defined desired value ranges. In this case, therefore
the selected LED 2 is arranged at the tenth location in the third
packaging unit R.sub.3. Consequently, the position P.sub.3,10, the
associated photometric measurement variables .PHI., C.sub.x,
C.sub.y and the updated number of z.sub.3=10 LEDs in the third
packaging unit R.sub.3 are stored in the data memory 6.
[0075] This type of assignment of the respectively selected LED 2
to one of the packaging units R.sub.1, R.sub.2, R.sub.3 ensures
that the average values of the photometric measurement variables
for the previously defined number N.sub.m of successive LEDs
definitely lie in the desired value ranges, to be precise
independently of the location of the packaging units R.sub.1,
R.sub.2, R.sub.3 from which the N.sub.m successive LEDs are
removed. In this case, it is also unimportant whether the N.sub.m
successive LEDs are removed in the order in which they were
arranged in the packaging unit, or in the opposite order.
[0076] FIG. 8 illustrates an intermediate step in which, after the
intermediate step carried out in FIG. 7, a further selected LED 2
is intended to be assigned to one of the packaging units R.sub.1,
R.sub.2, R.sub.3. In this case, it emerges, for example, that the
condition that the N.sub.m-1 LEDs last arranged in the respective
packaging unit in combination with the additional selected LED 2
yield average values of the photometric measurement variables which
lie in the previously defined desired value ranges is not fulfilled
for any of the packaging units R.sub.1, R.sub.2, R.sub.3. In this
case, therefore, the selected LED 2 is not assigned to any of the
packaging units, but rather is stored in the intermediate store 7.
Alternatively, it would also be possible to place the LED 2 again
into the supply container from which it was removed. The LED 2
stored in the intermediate store 7 or the supply container can be
assigned to one of the packaging units at a later point in
time.
[0077] The method described above is continued until all of the
packaging units R.sub.1, R.sub.2, R.sub.3 are equipped with the
desired number of LEDs. FIG. 9 illustrates the three packaging
units R.sub.1, R.sub.2, R.sub.3, for example, after they were each
equipped with a multiplicity of LEDs 2. To simplify the
illustration, only twelve LEDs 2 in each case are illustrated for
each packaging unit. In actual fact, the preferred number of LEDs 2
arranged in the packaging units R.sub.1, R.sub.2, R.sub.3 is in
each case at least 500, at least 1000 or even at least 5000 LEDs.
Typically, for example approximately 500 to 20000 LEDs 2 are
arranged on a roll functioning as a packaging unit R.sub.1,
R.sub.2, R.sub.3.
[0078] In one configuration of the packaging units R.sub.1,
R.sub.2, R.sub.3, the total number of the LEDs 2 arranged in the
packaging units is greater at least by a factor of 20 than the
number N.sub.m of successive LEDs, for which the average value of
the photometric measurement variables lies in the desired value
range. Particularly preferably, the total number of the LEDs 2
arranged in the packaging units R.sub.1, R.sub.2, R.sub.3 is
greater than the number N.sub.m by at least a factor of 100 or even
by at least a factor of 500. The number N.sub.m of successive LEDs
2 which fulfil the abovementioned conditions for the average value
of the at least one photometric measurement variable is preferably
3 to 25. The packaging units R.sub.1, R.sub.2, R.sub.3 are
preferably in each case identified with the number N.sub.m.
Particularly preferably, the packaging units R.sub.1, R.sub.2,
R.sub.3 are also identified with the at least one photometric
measurement variable, for example, the brightness .PHI. and the
color locus C.sub.x, C.sub.y, and the associated desired value
ranges.
[0079] N.sub.m LEDs can be removed from the fully equipped
packaging units R.sub.1, R.sub.2, R.sub.3 from an arbitrary
location, wherein the average values of the brightness .PHI. and of
the color loci C.sub.x, C.sub.y for this number of LEDs definitely
lie in the desired value ranges. By way of example, as indicated in
FIG. 8, the third to fifth LEDs could be removed from the first
packaging unit R.sub.1, the sixth to ninth LEDs could be removed
from the second packaging unit R.sub.2 or the second to sixth LEDs
could be removed from the third packaging unit.
[0080] Our methods and packaging units are not restricted by the
description on the basis of the examples. Rather, this disclosure
encompasses any novel feature and also any combination of features,
which in particular includes any combination of features in the
appended claims, even if the feature or combination itself is not
explicitly specified in the claims or examples.
* * * * *