Note: Descriptions are shown in the official language in which they were submitted.
Background of the Invention
There is considerable variation in cooking time~ among
microwave ovens even when considering only a particular model
o~ a given manufacturer. The dominant factor for this vari-
ation i5 differences in the output powers of the magnetrons
of the respective ovens; the~e differences result primarily
from differences in the powers provided by their respective
power suppliesO The power delivered to the magnetron in the
nearly universal power supply design depends on the effective
turns ratio of the plate transformer and the effective value
of the storage capacitor. While it would be possible to
measure and pair these components to produce a standard plate
current, the process for doing such would be very expensive.
Further~ the power ou~put of a given power supply would vary
substantially as a func~ion of ac line voltage which typically
may varv by as much as 30~ in domestic applications. It
would be possible to overcome the ou~put variance as a func
tion of ac line voltage, but the precision power supply
required would be prohibitivel-y expensive~ In short, the
relatively inexpensive power supply design used in most
domestic microwave ovens results in ovens of the same model
producing various ou~put powers even when operated with a
regulated ac line voltage~ For example, magnetron output
powers supplied by the power supplies with a regulated ac
line voltage for a particular model may vary from 600-750
watts with an averag2 of approximately 670 watts. Further,
an individual oven will exhibi~ a significant swing in output
power as a result of changes in the ac line voltage.
Variation in microwave cooking time~ described heretofore
has created problems for the microwave cooking industry. For
--1--
3~
example, manufacturers of prepackaged foods are unable to
provide accurate cooking directions and may lose customers
if the results are not satisfactory. Also, the user precisely
following a cook book recipe and the cooking time provided
therein will be dissatisfied i ~he food is overdone or
underdone. Fur~hermore, wi~h sta~e of the art cook-by-weight
ovens, the microprocessor algorithm for calculating cooking
times preferably includes a term deriYed from the predicted
output power of the magnetronO
The cooking time variance with microwave ovens is much
more critical ~han with conventional ga5 or elec~ric ovens
where the cooking times are substantially a function only of
the accuracy of ~he thermostat; the times do not vary
additionally as ~ function o the ac line voltage. Further,
in most conventional ovens, inconsistencie~ between the oven
temperature and the dial set temperature can be corrected by
a simple adjustmen~ to the dial. Also, users have developed
an understanding for how to compensate conventional cooking
- times when the oven i5 consistently not hot enough~ However
the same understanding is generally not present with users
who may be new to microwave cooking; this is expecially true
in view of the cooking time variation wi~h a given microwave
oven as a function of the ac line voltage.
From the foregoing, it is apparen~ that it i5 desirable
to provide microwave oven~ having constan~ uniform output
powers to establish standard predictable cooking times~ One
prior ark appro~ch to the general problem of non uniform
cooking ti~es i5 to monitor the ac line voltage and recalcu~
late the preset cooking time as a unction thereof~ Although
~his approach may provide some improvement for the cooking
3~
time variation as a function of a varying ac line voltage,
it provides no correc~ion for coolcing time variation caused
by differences in components of the power supplies o
respe~tive microwave ovens.
Summary of the Invention
The invention discloses the combination of an ac to dc
power supply, means for providing a siynal corresponding to
the output power of the power supply, and means responsive
to the signal for varying the number of ac cycles supplied
to the power supplv during sequential time intervals, each
interval corresponding ~o a fixed number oE ac line cycles,
the supplied ac cycles for a given time interval being dis-
tributed substantially unifo~nly thereover. It may be pre-
ferable that the varying means comprises a microprocessor.
Also, the varying means may preerably comprise a switch
connected between the ac line and the supply. Further, it
may be preferable that the fixed number of ac line cycles be
fewer than 150 cycles. Also, it may preferable that substan-
tially uniform distribution defines that when more than half
the ac cycles are supplied during one of the time intervals,
two cycles are not omitted in sequence~ Conversely, if fewer
than half the ac cycles are ~o be supplied, it may be preferable
that two ac line cycles are not supplied in sequence. Absolute
uniform distribution would mean ~hat the supplied line cycles
are time shifted before being supplied to the power supply so
that there is ~ constant time period between supplied cycles.
Howeverr substantially unifo~n distribution is intended to
also include the case where particular line cycles are omitted
by openiny a switch; the cycles which are coupled to the
power supply ~re not time shifted. More specifically, it is
intended to rninimize the number of consecutive cycles when
the switch is open and power is not coupled to the power
supply. By minimizing the number of consecutive off cycles,
3~3~
domestic light flickering is reduced. :[t may be p~eEerable
that the switch be opened and closed a-t approximately the line
zero current crossin~; for a substan-tially ln~uctive load,
these will occur after the line zero voltage crossing.
According -to one broad aspect, the present invention
provides a microwave oven, comprising: a microwAve cavity;
a magnetron coupled to said cavity; an ac to dc power supply
connected to said magnetron; means for providing a signal
corresponding to the anode current drawn fro~ said power sup-
ply by said magnetron; and means xesponsive to said siynalfor varying the number of ac cycles supplied to said power
supply during sequential time intervals, each of said time
intervals corresponding to a fixed number of ac line cycles,
said supplied ac cycles for each of said time intervals
being distributed substantially uniformly over each of sa.id
time intervals.
Preferably, substantially uniform distribution
provides that when more than half the ac line cycles of a
given time period are to be supplied to the high voltage
transformer, two ac line cycles are not skipped sequentially.
In other words, a switch between the line and -the high vol-
tage transformer is not open for two consecutive cyclesO
According -to a second broad aspect, the present
invention provides a microwave oven, comprisiny: a microwave
cavity; a magnetron coupled to said cavity; an ac to clc
power supply connec-ted to said maynetron, said power supply
--5~
having a high voltage transformer; means for yeneratiny a
signal corresponding to the anode curren-t supplied by said
power supply to said magnetron; means responsive to said
signal ~or determining the nun~er of ac cycles to be supplied
to the high voltage transformer of said power supply during
a time interval corresponding to a predetermined number of
ac line cycles wherein the power delivered by said power
supply is regulated towards a predetermined level; and means
for supplying said number of ac cycles to said high voltage
-trans~ormer of said power supply in substantially uniform
distribution over said ti~le interval.
According to a third broad aspect, the present
invention provides the method of regulating the output power
of a microwave oven to a standard output level, comprising
the steps of: providing a signal corresponding to the time
avera~ed anode current drawn by the magnetron from the high
voltage power supplyi periodically de-termining the magnitude
o~ difference between a calculated actual output level and
said standard output level, said calculated level being de-
rived in response to said signal; determining in responseto said magnitude of difEerence the number of ac line cycles
in the next of a sequence of time in-tervals to be supplied
to said power supply, each of said time intervals ~eing a
fixed predetermined nurnber o~ ac line cycles in length; and
supplying said number of cycles substantially uniformly
over said next time interval to said power supply.
According to a four-th broad aspec-t, -the present
invention provides the method of xegulatiny the outpu~ power
of a microwave oven magnetron to a standard output level,
comprising the steps of: supplying a predetermined number o:E
ac cycles to said power supply during a :Eirst time period
corresponding to a fi~ed number of ac line cycles, said
predetermined number not exceeding 70 percen-t of said fixed
number of ac line cycles, said power supply being connected
to said magnetron; generatin~ a signal corresponding to the
time averaged anode current drawn by said magnetron from said
power supply, said time averaged anode current corresponding
to the actual output power of said magnetron; determining
the magnitude of difference between said standard output
level and said actual outpu-t power of said magnetron; de-
riving the number of ac cycles to be supplied to said
power supply during a second time period to regulate said
actual output power of said magnetron towards said standard
output level, the magnitude of regulation being a function
of said dif~erence magnitude, said second time period being
e~ual to and following said first time period; and supply-
i.ng said derived number of ac line cycles during said second
time period.
3~7~
Brief Description of the Draw.inqs
The foreyoing and other objec~s ~nd advantages of the
invention will be more readily understood by reading the
following Description of the Preferred Embodiment with
reference to ~he drawings wherein:
FI~URE 1 is a block diagram/schema~ic o a microwave
oven embodying the invention;
FIGURE 2 iS a hardware implementation of the diagram of
Figure l;
FIGURE 3 is a fl~w diagram of the programming of the
microprocessor in accordance with the invention;
FIGURE 4 is a partially cut awa~ view of a microwave
oven having a scale;
FIGUP~E 5 is a view taken along line 5~5 of Figure 4;
FIGURE 6 is a partially cut away top view of Figure 4;
FIÇURE 7 is a view of the control panel of Fig~re 4; and
F~GURE 8 shows a reference between the ac line cycles,
supplied cyclesp ~nd anode current drawn.
2~
~r
37~
Description of the Preferred Embodiment
It has been determined that the power output from a
magnetron is fundamentally proportional to the anode current
that is drawn. Further, it was determined that even with a
drifting AC line voltage, the anode current or a voltage
corresponding to it could be sampled and the duty cycle of
the magnetron controlled in accordance therewith to provide
a microwave oven with stable output power. Also, similar
design microwave ovens could provide substantially the same
output power so that cooking times or foods ~ould be much
more precisely specified. In short, ~he power outputs of
microwave ovens could be made constan~ and uniform among the
ovens by regulating the respective power supplies.
Referring to ~igure 1, there is shown a block diagram/
schematic of a microwave oven embodying the invention. In
response to pulsed high voltage from power supply 14~ magnetron
12 supplies pul sed microwave energy to waveguide 18O The
microwave energy is coupled ~o cavity 16 by a rotating primary
radiator-20 which preferably provides a plurality of directive
radiation patternsO Microprocessor 10 controls the average
output power of magnetron 12 by regulating power supply 14.
More specifically, microprocessor 10 regulates the number oE
ac cycles supplied to power supply 14 in sequential 100 cycle
intervals and thereby reduces the maximum number of high
voltage pulses supplied to magnetron 12 during a given time
period. A preferred embodiment o~ the specific interconnec-
tions between these componen~s and the other co~ponents of
Figure 1 will be described in detail later herein with refer-
ence to Figure 2.
A small resistance viewing resistor Rv is connected
--1~
37~
between the high voltage suppl~ of power supply 14 and its
ground to provide a viewing voltage Vv which is proportional
to the anode current drawn. Voltage Vv is connected to
integrator 22 to provide appropriate time averaging. The
time averaging is important for two reasons. First, as
described earller herein, the anode current drawn through
resistor Rv is pulsed so that voltage Vv is also pulsed.
Second, the anode current fluctuates as a result of variations
in the loading on the magnetron caused by the rotation of
primary radia~or 20. Accordingly, integrator 22 provides
an average vol~age tha~ is proportional to the av~rage anode
current. Integrated voltage Vv is coupled to multiplexer
24~ At appropriate time intervals, microprocessor 10 selects
~ntegra~ed voltage Vv through multiplexer 24 for conversion
to a digital signal by A/D converter 26 and input to micro-
process4r 10. Stated simply, if integrated voltage Vv
which corresponds to the average anode current is larger
than the value requ,red to regulate to the desired power
setting, microprocessor 10 reduces the number of ac cycles
supplied to the power supply for the next time interval.
Conversely, if integrated voltage Vv is less than required,
the number of ac cycles supplied in the next time interval
is increased from the prior interval. ~n embodiment of
hardware implementation will be described in detail later
herein~
In accordance with the invention, the apparatus described
heretofore has significant advantaye over prior art microwave
ovens in that constant unifo~n output powers are provided.
By constant, it is mean~ that a particular microwave oven unit
~0 exhibits substantially the same or stable output power for
-~r-
dif~erent ac line voltage inputs. By unifo~m, i~ i5 meant that
diferent microwave ovens of ~he same or similar design provide
substantially the same output powers~ The constant uniform
output powers mean tha~ the cooking times for the ovens can
be precisely specified.
Regulation of the output power has parti~ular advantage
in a microwave oven that determines the cooking time as a
function of weight. ~ore specifically, if the weight of -the
food i5 input to microprocessor 10 and an algorithm is used to
determine the cooking tim~, the ~lgorithm pre~erably has a
term derived from the output power of the magnetron. However,
if the output power i5 not accurately known or varies as a
function of the ac line voltage, the cooking time cannot be
accurately calculated. Still referring to Figure 1, scale 28
provides an analo~ signal corresponding to the weight of the
food in microwave cavity 160 This signal is selected through
multiplexer 24 for conversion to a digital signal by A/D
converter 26 in preparation for input to microprocessor 10.
From the initial weight of the food and an operator input
through keyboard 30 corresponding to the initial temperature
of the food, microprocessor 10 accurately determines the
cooking time.
Referring to Figure 2, a hardware embodiment of the block
diagram of Figure 1 is shown. Trlacs 40 and 42 function as
switches and respectively determine whe~her ac line voltage is
delivered to heater transformer 44 and high voltage transformer
46. In normal operation, heater triac 40 .is closed a Eew
seconds before high voltage triac 42 and i5 left on continuously
during operation while high voltage triac 42 is used to regulat2
the number of ac cycles supplied to high voltage transformer 46
3~
during each 100 cycle interv~l. As shown, the secondary of
heater transformer 44 is connected to the heater of magnetron
12~ The high voltage supply of power supply 14 is a conven-
tional voltage doubler circult that is in wide usage. More
specifically, during half of the ac cycle/ capacitor 48 is
charged up to approximately -2000 volts. Then, in the
second half of the ac cycle, the charge on capacitor 48 adds
with the secondary voltage on transformer 46 providing a
voltage of approximately -4000 volts to the cathode of magne-
tron 12. This high voltage causes current to be drawn from
the power supply ground through viewing resistor Rv through
the magnetron to the anode Voltage V-~ is thereore direc~ly
proportional to the anode current drawn~ For a particular
combination of magnetron, feed structuret and cavity it was
found preferable to regulate the anode current to average
300 milliamps for full power operation. Further, it was
found preferable that the 300 milliamp average correspond to
an average or integrated Yy voltage of 2 ~ 2 vol~s~ This was
satisfied by selecting a value of approximately 7 3 ohms for
Rv. Also, it was found preferable that integrator 22
which time averages V~ comprise an RC filter having a time
constant of approximately one second. Aocordingly, the
respectiv values for RI and CI may preferably be 1 megaohm
and 1 microfarad. Integrator 22 .smooths out the pulsed
operation curve of magnetron 12 ~hich may typically have a
duty cycle of approximately .3. Also, integrator 22 compen-
sates for fluctuations in the anode current drawn resulting
from different load conditions as the primary radiator rota~es.
The integration of voltage Vv is coupled to multiplexer
24 and is sele~ted therethrough in response to microprocessor
3~
control as governed by perip~eral int:erface device 50. ~lso
coupled to multiplexer 24 is an analog signal from scale 28
which may be used in a cook-byweight algorithm~ Also,
other analog inputs such as a ~empPrature probe ~ay be
sampled through multiplexer 28.
For commercial applications, it may be prefe~able that
the microprocessor control be provided by a customized in~e-
grated circui~ which includes therein many of the in~erface
functions. The embodiment of Figure 2 shows a general purpose
microprocessor 52 with ancilliary hardware and in~erfaces
coupling it to the microwave oven control panel~ sensors, and
magnetron control~ An example of microprocessor 52 that could
be used is an MOS Technology, Inc. MCS6502. As shown in
Figure ~, the microprocessor is connected to data bus 54
which typically compri~es eight lines which may be connected
to MCS6502 pins 26-33, respectively. The microprocessor is
also connec~ed to address bus 56 which typically comprises
sixteen lines which may be connected to MCS6502 pins 9-25,
re~pectively. Conventional initia~ing circuitry (INIT) 58 is
used only at power up ~ime by the microprocessor and may be
connected to input pins 6 and 40 of microprocessor MCS65020
~urther, a conven~ional crystal clock (CLOCK GENerator) 60 is
required and may be input to the microprocessor on pins 37 and
39, Line 62 i5 used to provide ~he clock to peripheral
interface devices 50 and 64, program memory (ROM) 66 and
da~a memory (RAM) 68. Microprocessor 5~ provides the same
functions as microprocessor 10 described with reference to
~igure l; in Figure 1, the interface devices are included
within hlock 10. The program memory 66 which preferably is a
read-only memory stores the operational program~ Th~ task of
/~
33~
writing the program from the requirements given later herein
is well known to one skilled in the art, Microprocessor 52
provides addresses to address bus Sfi to fetch instructions
from program memory 66 and data from data memory 68 which
is a random access memoryO Write enable and other control
functions are provide~ from microprocessor 52 to data memory
68 or peripheral in~erface devices 50 and 64 on control bus 70.
Peripheral interface devices 50 and 64 allow micro-
processor 52 to read data from keyboard 30, to test the
state of sensors and switches, display the results of in~ernal
operations and control the magnetron. Example peripheral
interface devices 50 and 64 are MCS6522's which may have pins
21-40 connected to control, timing, interrupt~ da~a bus and
address bus. Peripheral interface device 64 provides interface
~or control panel 72 which includes keyboard 30 and displays
74. Keyboard inputs to the microprocessor are provided by a
conventional matrix scan technique. More specifically, the
keyboard comprises a matrix of switches which may be of the
contact or capacitive touch variety~ For the co~trol panel of
Figure 7, a 4 x 6 matrix would be sufficient; however, a
larger matrix will be described and it is assumed ~hat it
may contain functions not discussed hereinO Output signals
are sequentially provided to the columns of the matrix, and
the rows are sensed and decoded. In detail, pins 10-17 of
MCS6522 are connected to eight lines 76 connected to high
current output buffer 80 and segment output port 78. At
~he output of high current output buffer 80, which may, for
example, be a 74LS374~ eight lines 82-89 as indicated connect
through eiyht amplifiers 90 to the keyboard. Sequence
column scanning pulses are provided on lines 82-89; the rows
-~5-
of the matrix of switches of the keyboard are sensed by
lines 92 which are connected to pins 1-9 of peripheral in~er~
face device 64. The sensed data is decoded whereby micropro-
cessor 52 determines which switches of the switch matrix of
keyboard 30 ar~ closed.
Digital displays 74 are scanned which means that each
digit is driven for a short period of time, such as two
milliseconds, in sequence. The entire display is scanned at
a rate which the eye cannot detec~. Lines 82~8~ are coupled
through driver circuits, two circuits in Figure 2 being
represen~ative of ight in the embodiment~ Each conventional
circuit as shown comprises Vcc which is typically ~5 volts
Rl which may be 1.5K ohms, R2 which may be 1.0K ohms, and
transistor Q. These sequenced driver circuits determine which
digit of the display is activated. The data that determines
which segments of a particular digit are on is determined by
the output of segment output port 78 which is coupled to
lines 94 101 through resistors 103 ~o displays 74. ~n example
of a segmen~ output port is an MC3482~ The data and scan
pulses time share lines 76, the enable control to port 78
and buffer 80 being provided on lines not shown by peripheral
interface device 50 on pins 3 and 4, respectively~
Microprocessor 52 controls ~he output of magnetron 12
through peripheral interface device 50. More specificallyl
outputs from peripheral inte-rface device 50 on lines 104 are
connected to high current output buffer 106 which may be, for
example, a 74LS374D Two of the outputs of buffer 105 are
connected to conventional optical isolators 108 and 110 which
may be, for example, MOC30109s. A LOW voltage (logical 0)
at the input of an optical isolator causes the internal
re~istance of its output to be a short circui~.
In response to a con~rol signal from optical isolator 108,
triac ~0 i5 turned on energizing heater transfor~er 44. In
response to a con~rol signal from optical isolator 110,
triac 42 is turned on energiæing the high voltage power supply.
Figure ~ illustrates the logic control of microproc~ssor
52 of Figure 2 over magne~ron 12~ The program of programming
memory 6Ç of the microprocessor in accordance with Figure 3
and the discussion given herein is well known to those
skilled in the art. When the command is given ~o START the
magnetron, microprocessor 52 turns on heater triac 40 through
peripheral interface device 50, high current output buffer
106 and optical isolator 108 as described earlier herein.
AC current flowing through triac 40 to heater transformer 44
preferably i~ supplied for more than 3 seconds to heat the
cathode prior to supplying the high voltageO If the heater
has been energized within the last 3 seconds, ~he delay may
not be necessary. Next, he variable COUNT is set to the
specified percent power times 100 but not more than 70. For
example, if the operator has selected the oven to operate at
half power, COUNT is set to 50 (.53 x 100). If the operator
has selected the oven to opera~e at full power~ COUNT is set
to the maximum initial value of 70. Microprocessor 52 next
turns on the high voltage supply triac 42 through peripheral
interface device 50, high current outpu~ buffer 106 and
optical isolator 110. Triac 42 ~unctions as a switch providing
ac line voltage to high volta~e transformer 46 for COUNT
numb0r of ac cycles out of the next 100 cycles. The switching
is preferably done at the ac æero current crossing so tha~
high current will no~ be switched. A conventional æero
3~
crossing detector output is supplied to microprocessor 52 to
provide the required timing. The active pulses or cycles
are distributed uniformly within ~he next 100-cycle time
period so as reduce line current surges and fluctuations
More specifically, if the required duty cycle is greater
than 50% (COUNT greater than 50 ), only one pulse is skipped
in sequence. If the required duty cycle is less ~han 50%,
only one pulse will be active in sequence. After 100 ac
cycles ~1.67 seconds)~ the anode current is meas~red by the
microprocessor selecting the output of integrator 2~
through multiplexer 24 and converting it to a digital signal
in analog-to-digital converter for input to peripheral inter-
face device 50. The anode current is then compared to the
operator specified anode current For example, as described
earlier herein, full power in the preferred embodiment corres-
ponds to an average anode current of 300 milliamps. Accordingly~
if half power had been selected, the specified average
anode current would be half of 300 milliamps or 150 milliamps.
Further, as described earlier herein, component~ were selected
so that an average anode current of 300 milliamps corre~ponds
to an average voltage of 2~2 volts at the input of multiplexer
240 Accordingly, a lul volt signal at the input of the
multiplexer would correspond to an actual anode current of
150 milliamps ([1.1/~.2] x 300~. If the actual and specified
anode currents vary by more than 20 milliamps~ COUNT is
either increased or decreased by 3 to make the two more
equal. If they differ by 11-20 milliamps, COUNT is either
increased or decreased by Z to make the ~wo more equalO If
they differ by 4-10 milliamps, COUNT is either increased or
decreased by 1 to make them more equal. I~ they differ by 3
~ /~
or fewer milliamps, COUNT remairls unchanged. Then, the
magnetron high voltage is turned ON for COUNT number of
pulses during the next possible 100 pulses. In short, the
actual average anode current is adjus~ed to be equal to the
specified anode current by appropriately adding or deleting
the number of magnetron pulses within ~sequential 100 pulse
or cycle intervals, the adjustment being greater when the
two differ by a greater amount~ As an example, if full
power or an average of 300 milliamps of anode ~urrent has
been selected, and that corresponds to 94 ac cycles out of
100 for the particular ac line voltage, there would be an
initial maximum of 70 pulses of high voltage to the magnetron
during the first 100 cycles of ac power. Then, the number
of pulses in each 100 cycles would be increased from 70 by 3
unt.il the difference was 20 or less (74 pulses)O Then, the
number of pulses in each 100-pulse interval would be increased
by two until the difference was 10, and so forth.
Ref erring to F igures 8 a-8 c, there is shown the corres~
pondence bet~?een ac line voltage and the anode current drawn by
the magnetron. More specifically, Figure 8a provides an ac
line reference which typically is 60 or 50 cycles per second
depending on the countryO Figure 8b is an example of the ac
line voltage that may be supplied to high voltage transformer
46~ More speci~ically, with triac 42 functioning as a switch
under the control of microprocessor 52 through interface
device 50, high current output buffer 106 and optical isolator
110, the seond and fifth ac line cycles of the sequence of
Figure 8a are prevented from energizing high voltage transfor-
m r 46. It was stated earlier that it is preferable to switch
at the zero current crossing. If the load is highly inductive
- _~9_
97~
such as the typical microwave oven, the zero current crossing
is approximately 90 after the æero voltage crossing.
Accordingly, Figure 8b is intended only to be representative
of the individual selection of cycles to be passed or deleted.
It is noted that heater triac 40 is closed for the entire ac
cycle sequence so that heater transformer 44 is continuosly
acro6s the ac line. Figure 8c shows the anode current that
is drawn by ~he magnetron. The duty cycle of ~he pulsed
magnetron is typically in the range from 0.25 to 0.35.
It was stated earlier herein the ac line cycles supplied
to high voltage transfonner 46 during a given time interval
are substan~ially unio~nly distributed over ~he time interval.
More specifically, if more than half of the available ac
cycles o the time period are to be supplied, it may be
preferable that triac 42 functioning as a switch not be open
for more than one ~ycle at a time. Conversely, i ewer
than half the available ac cycles of the time period are to
be supplied, it may be preferable that triac 42 functioning
as a switch not be closed for more than one cycle at a time.
According, the fluctuation or surge on the a~ line is thereby
minimized. For example, the perceptible flickering of dom-
estic lights is reduced or eliminated. A preferable soft-
ware algorithm for unifo~nly distributing the supplied ac
cycles over a particular interval is to add COUNT as defined
herein to the contents of a register for each available ac
line cycle. If the contents of the register is greater than
the number of ac cycles in the interval, triac 42 is turned
ON Gr that ac line cycle and the number of cycles in the
interval is subtracted Erom the contents~ If the conten~s
of the register is not greater than the number oE ac cycles
,~G/
3~
in the lnterval, triac 42 is no~ turned ON for that ac line
cycle~ Although an interval of 100 ac line cycles was described
earlier herein, other length intervals may be used as well;
in fact~ the quicker response ~ime of shorter in~ervals may
be preferable in cer~ain application. The Appendix shows a
table derived using the above described software algorithm
and the time base interval of 60 cycles. It shows that the
ON cycles are substantially uniformly distributed over the
time interval. The "O"'s represent triac 42 being open for
the particular ac line cycle 50 that ~he high voltage trans
former is not energized. The "X"'s represent the triac 42
being closed for the particular ac line cycle so that the
high voltage transformer is energized~ For COUNT 36~ for
example, 36 out of the 60 available cycles in the interval
are to be supplied ~o the high voltage transormer and they
are to be distributed over the 60 cycle interval of one
second. COUNT 36 is added to the register ~nd because the
contents is less than 60, the function of triac 42 is an
open switch for the first ac line cycleO Next, COUNT 36 is
added to the register resul~ing in 72. Because 7~ is greater
than 60, the function of triac 42 for the second ac line cycle
is a closed switch and then 60 is subtracted from the total
leaving 12. For the third ac line cycle, COUNT 36 is added to
the register value of 12 providin~ a sum of 48. Because that
is less than 60, the function of triac 42 is an open switch.
This process continues for the entire interval which for this
example is equivalent to 60 ac line cycles or one second. Then
a new COUNT is calculated as described with reerence to Figure
3 and the process continues.
Referring to Figures 4, 5, and 6~ there are respectively
c~
shown partially cut away front elevation, side and top views
of a microwave oven having a scale 28 for using the invention
to advan~age, Heating cavity 16 contains a food body 112
positioned therein through an access opening provided by a
door (not shown). Many well known and conventional parts
such as, for example, the door seal structure are not shown
as they form no par~ of the invention. It is preferable that
microwave energy at 2450 MHz from a conventional magnetron 12
be coupled through waveguide 18 to a rotating primary radiator
20 whiGh has a pa~tern characterized in that a substantial
portion of the energy is absorbed by ~he food before being
reflected from the walls of the cavity. More specifically,
primary radiator 20 comprises a two-by-two array of antenna
elements 20a where each element is an end driven half wavelength
resonatlng antenna element supported by a len~th of conductor
20b perpendicular to the elemen s and the upper wall of the
microwave oven cavity. Parallel plate microstrip transmission
lines 20c connect each of the suppor~ conductors to a center
junction 20d axial ~o rotation. At the ~unction, a cylindri-
cal probe antenna 100 is attached to the radiator 20 structure~
Probe antenna 100 which has a capacitive hat 102 is supported
by a plastic bushing 117 positioned within the waveguideD
The bushing permits rotation of the probe antenna and radiator
arollnd the axis of the probe antenna. Microwave energy
introduced into waveguide 18 by output probe 113 of magnetron
12 excites probe antenna 100. Energy couples down probe
antenna 100 which functions as a coaxial conductor through
hole 119 in the upper wall of the oven cavity. ~he upper
wall of cavity 16 is shaped to form a dome 127 having a
flattened conical shape extending outwardly in the wall to
_~/
provide a nearly circular recess partially surrounding the
directive rotating radiator and provide uniEorm energy distri-
bution in the product being heated. The dome returns micro-
wave energy reflected from the food body toward a circular
area in the middle area of the microwave oven cavity~ It is
preerable that air from a blower (not shown) used to cool
the magnetron be circulated through the cavity to remove
vapors. It may be preferable that this air be channeled into
waveguide 18 and passed through apertures 121 in the wall of
the dome to provide rotation of radiator 20r Radiator 20 is
connected to fins 123 to provide a suitable force for the
air driven rotation. The fins may be fabricated of a plastic
nonlossy material. Other paths may also be used to direct
the air from the blower to the fins. Also, in lieu of the
air driven method, an electric motor ~not shown~ may be used
to provide rotation of the radiator. Grease shield 125 i~
transparent to microwave energy and provides splatter isola-
tion from the rest of the cavity.
- Control panel 72 which i5 shown in detail in Figure 7
provides keyboard functions which are inputs to the control
microprocessor 52 and display functions by whi~h ~he micro-
processor indicates status to the user~ Any of A number of
conventional keyboard switches and displays could be used~ ~t
may be preferable ~hat well known capacitor touch pad switches
be used for the keyboard. Also, it is preerable that the
display provide digital read out of parameters such as time
and a simultaneous indication of what keyboard entries have
been selected. Specific preferable ~unctions of the control
panel will be described in detail later herein.
Positioned below the floor 118 of the cavity is scale 28
~2-~-
7~
The scale has fol~r vertical support pins 122 which respectively
protrude through holes 124 in the floor of cavity 16 in the
proximity of the corners, Supported on the pins is plate 126
which rests approximately one inch above the floor of the
cavity at the corners. Typicallyt the plate i~ made of a
pyrex glass material which is transparent to microwaves, The
microwaves pass through the glass, s~rike ~he floor of the
cavity and are reflected back up into the food body from the
bottom side. This allows the microwave energy to enter the
food body from all sides. Also, the plate may provide some
protection for the magnetron if the oven is accidentally
turned on when there is no load in the cavity. Although the
glass plate may be removed for cleaning, it should always be
in the oven during operation~ The weight of ~he glass plate
and any food bodies and dishes placed thereon is transferred
through support pins 122 to scale 28.
It is desirable that substantially no microwave energy
pass through the four pin holes 124 into chamber 128 below
the cavity which houses the scale. Accordingly, the pin
holes 124 which may preferable be circular, are less than one
half wavelength in circumference. More specifically, the
holes are slightly larger than the pins which are approxi-
mately one quarter inch in diameter. To minimize inaccuracies
in scale weighings, it is important that there be as little
friction as possible for a pi~ as it moves up and down through
a hole; this may be accomplished by selecting tolerance~ that
accurately position the pins to be concentric with their
respective holes and by using materials that have low co-
e~ficients of friction. ~t i~ preferable tha~ the pins be
fabricated of a microwave transparent material such as a
-,2~
3~
ceramic to provide a microwave choke through the holes. If a
pin were metallic, the structure would exhibit the properties
of a coaxial line wi~h the outer conductor being the surface
of the hole and the center conductor being the pin. Micro
wave energy would pass even though the size of the outer con~
ductor was below cutof f .
Scale 28 comprises four rigid lever arms 136~ Each lever
arm has an inverted V-bracket 137 on one end to support the
arm rom a knife edged fulcrum 14~ At the other end, each
arm is attached to a second arm by a semicircular pivot pin
141 so that there can be vertical motlon at the joint of the
arm pair between the fulcrums at ~he opposite ends, The pairs
of lever arms 136 50 described are positioned parallel to each
other so that each arm of the pair has a corresponding arm in
the other pair. The corresponding arms are rigidly attached
by a V shaped cross bar 143 running perpendicular to the
connected lever arms. In the disclosed embodiment of scale
28 used to advantage with the invention, each arm i5 approxi-
mately seven inches long and ~he cross bars which are fourteen
inches long are attached approximately one inch from the
fulcrums. The scale was designed with these dimensions ~o
that it would fit in chamber 128 and the pins would protrude
through holes 124 at appropriate places. The compliant
member 144 which resists downward motion of the lever arms
at the pivot pin 141 joint is a ~lexible metal strip that is
~upported in cantilever fashion rom block 146. Rod 148 is
attached rigidly and perpendicular to one of the lever arms
near the pivot pin joint. The rod has a disk 150 on the end
which rests on compliant member 144.
As described earlier herein, the weight of plate 126 and
,~
~ 7~ ~
any objects placed theron is transferred to the scale by pins
1~2 which protrude into ~he cavity through holes 124 in the
bottom cavi.ty wall. Pins 122 are attached to rectanyular
brackets 152 which limit the upward movement of the pins
through holes 124. The rectangular brackets 152 are rigidly
connected at inside bottom points of V-shaped cross bars 143
adjacent to the respective lever arms~ Regardless of the
distribution of downward fo~ce between the four pins 122 t the
force is transferred in approximately the same ratio by the
cross bars to the lever arms on the compliant member side of
the scale. Rod 148 couples the force from the lever arms
through disk 150 to the compliant member 14~. As the weight
and corresponding downward force is increased, the flexible
compliant member bends more; the compliant member is analogous
t~ a spring. The vertical position of the unsupported end of
the compliant member is therefore a function of the weight
exerted on pins 122. The unsupported end of compliant member
144 is bent downward to form a shade member 157 that shields
a particular portion of light beam 154 from being incident
on light sensitive device 156. As the weight on plate 126 is
increased so that the unsupported end of compliant member 144
bends further downward, a greater portion of the light beam
is blocked from being incident on light sensitive device 156.
Light sensitive device 156 may preferably be a phototransi.stor
which provides an analog voltage which is a function of the
light incident upon it. The source 158 of the light beam 154
may be a light bulb as shown or more pre~erably a light
emitting diode. It may be preferable to position a concave
lens between the source of light and the light sensitive
device to focus the beam of light to a relatively small areaO
-~8-
Accordingly, the intensity within that area would be varied
rather than varying the area of light incidence.
Scale ~8 provides a means for providing microprocessor 10
(or microprocessor 52 of Figure 2) with an inpu~ indicative of
the weight of objects in cavity 16. A substan~ial advantage
of scale 28 so described is that it can be installed in
commercially available microwave ovens withou~ significant
retooling More specifically, in the particular microwave
oven to which the scale was embodiedl chamber 128 had a height
of 3/8 inches in the center and approximately 1 1/2 inches at
the corners and edges. Figures 4, 5 1 and 6 have not been
drawn to scale. The corners and edges of the floor 118 of
cavity 16 have always been raised so that a food body supported
on pla~e 126 would be elevated from the conductive surface of
the floor where dielec~ric losses would be very low. The
scale which has a height of approximately one inch has its
structure in a rectangular shape with nothing in the center
so that it fits around the perimeter of chamber 128 where
the height is approximately 1 1/2 inches. Furthermore,
because there is no s~ructure in the center of the scale, it
can be adapted for use in a bottom fed microwave ovenO
The reference clock for microprocessor 52 is provided by
clock 60 Conventionally, clock 60 comprises an AC filter
connected to the 60 Hz AC power line and a %ero crossing
detèctor, the output of which is coupled to the microprocessorn
Referring to Figure 7, there is shown an expanded view
o~ control panel 72 which comprises keyboard 30 and display
74. As stated ~arlier herein, it may be preferable that
the keyboard switches be conventional capacitive touch pad
switches. Typically, a touch panel interface may be connected
,~
~2-~-
~ 73~
between the keyboard and the microprocessor; the interface
is of conventional desiyn and is included in many commercially
available microwave oven models~ Similarly, a high voltage
driver interface may be connected between the microprocessor
and displays of control panel 72 to provide lighted indicators.
The kevboard includes touch pads 200 nl1merically labeled
0-9, functionally labeled CLOCK, READY TIME~ DISH WEIGHT,
THAW, WARM~ HEAT, COOK PROGRAM, STIR, TIMER, REDUCÆD POWER,
TIME~, and push switches 202 lab21ed START/R~SFT and LIGHTo
The display includes digital read outs 20~, function indicator
lights 206 associated with functionally labe]ed touch pads,
and digital read out 208 associated with the COOK PROGR~M
function p~d.
In operation, touch pads labeled 0-9 may generally be
used conventionally to enter data for well known functions
into the microprocessor. For example when the microwave
oven is not being used~ digital read outs 204 display the
time of day 7 ~0 change the time of day~ the user pushes
numerical pads corresponding to the desired time; this time
is displayed in digital read outs 204. Then, when the user
pushes CLOCK, the displayed time is entered into the micro-
processor and becomes ~he new time of day. Another example
is to use the numerically labeled pads to display the amount
o time food is to be cooked. Upon pushing START9 the display
time counts down until the o~en shuts off. The THAW function
pad is used to acti~7ate the microprocessor to control the
magne~ron so that the food is raised from frozen food at 0F
to thawed food a~ 40~. The WARM function pad is used ~o
activate the misroprocessor to control the magnetron so that
the food is raised from 40F to 65F. The HE~T function pad
3~
is used to activat~ the microprocessor to control the mag-
netron so that the food is heated from 65F to 160F. The
COOK PROGRAM function pad i5 used to activa~e the micro-
processor to control the magnetron so that the food at 160F
is taken through the cooking process which may or may not
raise its temperature to above 160Fo In other words, the
THAW, WARM, HE~T and COOK inpu~s are indicative of the initial
temperature of the food. Before in.itiating cooking, the
COOK PROGRAM which i5 appropriate for the particular food
being cooked may be selected by touching an appropriate
numerical pad and then touching COOK PROGRAM. The selected
program is displayed in d.igital read out 208. When in a
cook-by~weight mode which will be described in detail herein,
~he REDUCE~ POWER pad may be touched to ~ctivate T~MP HOLD
which decreases the duty cycle of the magnetronO The 1/2,
1/4 and 1~8 indicators are activated by successive touchings
of the R~DUCED POWER pad during conventional cook-by-time
operation. The READY TIME functlon pad i5 used to program
the microwave oven to come on at a future time~ The STIR
TIMER is used to sound an alarm and shut off the oven at a
time when the food is to be stirred or other action taken
within the ovent The TIMER f-unction is used as a count down
clock to an alarm for timing which may or may not be associated
with the microwave oven~ The START button initiates execution
of a particular selected programmed subroutine which turns
the magnetron on. The STOP/RESET button causes the magnetron
to be turned off. Successive pushings o~ the LIGHT button
causes a light ~not shown) illuminating the cavity to be turned
on and off~
The programming of the microprocessor to regulate th~
93~
output power of the magnetron has been described earlier
herein. It has been s~ated that the inventive principle has
par~icular advantage when used in combination with a microwave
overi having a scale coupled ~o the cavi~y wherein cooking times
are calculated from the initîal weight of the food in the
cavity and an operator input relating to the initial temper-
ature of the food. As described with reference ~o Figures 1
and 2, an analog signal corresponding ~o ~he initial weight
of the food is sampled by ~he microprocessor. The programming
of the microprocessor which is known to those skilled in the
art will now be described for ~he calculation of cooking times.
It should be under~tood that ~he microprocessor may preferably
perform many other functions than the ones d~scribed herein.
For example, the microprocessor may monitor a temperature
probe, monitor an interlock, cook for a set time, and cook at
a set power.
The following equatlon is used to CALCULATE BEATING TIMES.
[HUS~ ~FW ~ (DW~ (SHD) 3
Heating Time =
[OPL] [PLS] [CF]
where HUS is Heat Units Selection, ~ is Food
Weight, DW is Dish Weight, SHD is Specific Heat of Dish9 OPL
is Oven Power Level~ PLS is Power Level Selection and CF is
Coupling Factor.
The first term in the heating time equatiorl is Heat
Units Selection which i5 expressed in BTUs per pound of food.
It has been found that the required heat units per weight unit
of food is in part a function o~ the temperature range over
which the food is to be heated and chemical and/or physical
changes taking place within the food. By a very simplified
,,,~
user input from the keyboard, this term of the equation is
determined, More specifically, referring again ~o Fiyure 7,
the user indicates the initial temperature stat~ of the food
by touching ~HAW which as labeled is for ~rozen foods (0F),
WARM which as labeled is for cold foods ~40F) such as out
of the refrigerat~r and/or ~IEAT which as labeled is for food
at room temperature ~65F)~ Touching of more than one of
these pads initiates a separate cycle for each function and
a separate calculation of the heatiny time equation for each
cycle. For the Thaw cycle, 100 BTUs per pound is entered
into the equation; for ~he WARM cycle, 25 BTUs per pound is
entered into the equation; for the HEAT cycle, 100 ~TU's per
pound is entered into the equation; and ~or the COOK cycle,
25-250 BTUs per pound is entered into the equation depending
on the COOK PROGRAM that is selec~ed by touch pads and that
i5 displayed within the COOK PROGRAM ~o~ch pad. Although the
Heat Units Selection entry into the equation for COOK de-
~ermines the heating time for a maximum power levelp that
time will be increased by a specific factor if a REDUCED POWER
s~tting is selected. In other words, the same number of BTUs
for the cooking task are delivered but ovPr a longer period
of time for more delicate cooking or simmering.
The second term in the heating time equztion is [Food
Weigh~ ~ (Dish Weight) (Specific ~eat of ~ish~]~ The presence
of the Food Weight in the equation i~ obvious; ~he multipli-
cation of its units (pounds) by the units of Heat Units
Selection (BTU per pound) yields ~TUs for the numerator of
the equation which ~7hen divided by the units (BTUs per minute~
of the denominator, gives the quotient in minutes which are
the desired units. The inclusion of (Weight Dish) (Specific
--~r-
~eat of Dish) is to compensate for a certain portion of the
heat which is provided to the food being transferred to the
dish by conductionO In other words, more heat must be delivered
to the food than might be thought necessary because some of
it is lost by conduction to the dish. For user simplicity,
the speciic heat of the dish in the calculation of the
heating time equation is assumed to be a constant of 0~2 for
the W~RM and HEAT cycles where the tempera~ure of the dish
is raised by conduction as the temperature of the food rises,
For the TH~W and COOK cycles, the specific heat of the dish
is set equal to z~ro to eliminate ~he product of it and dish
weight from the equation; with THAW, the BTUs transferred to
raise the temperature of the dish i5 insignificant compared
to ~he BTUs ~o thaw the food and with COOK, which starts at
160F, there is no appreciable rise in temperature. Although
a more exacting expression of the hea~ los~ by the food (and
accordingly the additional heat requlred ~o be delivered to
i~3 would also include the specific heat of the food and
heat rise in gases in the cavity~ empirical analysis has
showed that the assumptions were adequate for proper operation
of the oven using the heating time equation. In operation,
when the light indicator on the DISH WEIGHT pad is on~ it i5
indicative that a dish weight is stored in the microprocessor~
Therefore, to commence a new cooking process with a new
dish, the DISEI WEIGHT pad i.s touched and the light indicator
goes out; thi~ erases the previous dish weight from the
microproC~SSQr memory and "zeros the scale'~ The weigh~ of
the dish may then be set up for entry into the micropro-
cessor by either entering it through ~he numerical touch
pads if it is known or by placing the dish without food i~
r ~/
--3~
~3~
the oven where it depresses ~he scale. With a second touching
of the DISH WEIGHT pad, the .indicator li.ght thereon goes on
indicating that ~he new dish weiyht has been entered into the
microprocessor. It may be prefera~le that the analog voltage
at the output of light sensi~ive device 156 be somewhat
linear with the weight that is placed on the scaleO With
this being the case, a linear analog to digital converter
properly scaled can be used so that the microprocessor directly
samples weight in pounds. If the analog voltage is not
linear with weight such as being inversely proportioned as
the embodiment of Figure 4, it can be compensated for in the
microprocessor by such conventional ~echniques as a lookup
table. For accuracy of weighing t it may be preferable that
at a weighing time, the microprocessor take a plurality of
weight samples~ discard high and low weights, and average
the remainder of ~he weights. The weight of the ood is cal-
culated by the microprocesscr by using the weighing immedi
ately prior to the STA~T button being p~lshed and subtracting
the weight of the dish after zero adju~men~O
The ~irst term in the denominator of the heating time
equation is Oven Power Level. In a cook-by-weight oven
developed before the output power regula~ion syskem disclosed
herein, the output power had to be roughly estimated because
it varied considerably rom oven to oven; further~ with a
particular oYen, the o~tput power ~aried as a function of
the AC line voltage, In short, there were siynificant errors
in the calculated cooking ~imes that resulted rom not accurately
knowing the output power~ In accordance wi~h ~he inventive
principle of regulating the power supplied ~o ~he magnetron,
the term Oven Power Level is accurately known because for
-
full power, the anode is held constant at 300 mllliamps
which corresponds to 725 output power or 41.2 BTUs per minute.
~ he second term in the denominator of the hea~ing time
equation is Po~er Level Selection. I the REDUCED POWER pad
has not been used ~o select TEMP HOLD, a value of 1 is used
for PLS in the heating time equation. If the REDUCED POWER
pad has been used to select TEMP HOLD, 0.3 plu5 0~04 per
pound of food is input to the equation. For example, if the
food weights one pound, ~he magnetron will operate at 34
perc~nt of full power. Fur~her, if the food weighs two pounds,
38 percent of full power will be outputted. This is imple-
men~ed by decreasing ~he duty cycle of the magnetron. In the
past, it was generally accepted that juQt as ~ome foods cook
better conven~ionally at lower rather than higher temperatures,
some foods cook better at reduced microwave energy powar
levelsO ~ccordingly, most microwave ovens provide many power
level selections. As par~ of the development of the cook-by-
weight process, it was found most impor~ant to determine the
total number of BTUs required for ~he par~icular food and then
2~ deliver the~; however~ ~hP rate at which microwave energy is
supplied is not so critical. In fact~ the TEMP HOLD feature
provides only one reduced power level setting and that is a
function of the weight of the food. Generally, the reduced
power of TEMP HOLD is used to best advantage wi th food having
a large volume where the microwave energy penetration ~o th~
center o the food i5 greatly reducedO ~dditional cooking
time may ba desirable to pexmit heat in the outer portion oE
the food to conduct ~oward the cencer for more uniform heating
and cooking~ It has been found that 'che most appropriate
reduced power setting is one which holds the food at temper-
~,3
,,~,
~3~7~
ature which for lightweight foods is approximately 30 percent
of full power. The additional 4 percen~ per pound in the
PLS formula compensates for larger food bodies having greater
surface areas and therefore greater heat losses that mu,st be
compensated for to maintain temperature. The assumption
that food surace and size gerlerally relates to weight has
been empirically tested.
The last term of the heat time equation is Coupling
Factor. Not all of the microwave energy output from the
magnetron is coupled into the food. Some of the energy is
lost in the system such as in the walls~ waveguide, and the
plate. The percent of ~otal energy that is converted into
heat in the food is in part a funrtion of the fGod surface
area and its absorptivity. For example, if one potato takes
four minutes to cook, ~wo potatoes will generally take les~
than eight minutes or twice that. This is because as the
load is increased, a larger percentage of the total power is
absorbed by the food. It has been found that the distri-
- bution of energy into the food with respect to losses is
approximately expressed by the following formula~
Food Weight
Coupling Factor =
Food Weight ~ K
In essence, the constant K can be viewed as losses of the
oven expressed in terms of weight. Constant K has been
assigned the value oE 0.1. Accordinglyl i~ the food weighs
0.1 pounds, the coupling factor is one half or the heating
time is incr~ased by a factor of 2 over which it would have
other~.7ise been. If, however, the food weighed 1.0 pounds,
the h~ating time would only be increased by a factor of 1.1.
In Figure 1, th~ block for a microprocessor block 10 indicates
that the heating time per weight unit decreases as a function
of increasing weight because of the improved coupling of
microwave energy into ~he greater food mass.
This concludes the description of the Preferred Embodimerlt.
The reading of it by one skilled in the art will bring to
mind many modifications and alterations withou~ departing
from the spirit and scope of the invention. Accordingly, it
is intended that the scope of the invention be limited only
by the appended claims~
~0
~,~j S
APPENDIX
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00oooooooooooooooooooooooooooOooooooooooooooooooooooooocooox COUNT - 1
OOOOOOOOOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOOOOOOOOOOX COUNT = 2
OOOOOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOX COUNT = 3
OOOOOOOOOOOOOOXOOOOOOOOOOOOOOXOOOOOOOOOOOOOOXOOOOOOOOOOOOOOX COUNT ~ ~
OOOOOOOOOOOXoooooOoooooXoooooooOoOoXoOOOOOOOOOOXOOOOOOOOOOOX CO~NT = 5
OOOOOOoooXOOOOOOOOOXoooo~ooooxoooooOooOXoooooooooxooooooooox COUNT = 6
OOOOOOOOXQOOOOOQOXOOOOOOOXOOOOOOOOXOOOOOOOXOOOOOOOOXOOOOOOOX COUNI' = 7
OOOOOOOXoOooooXoooooooXooooooXoooooooXoOoOoOXOOOOOoOXOo~oOOX COUNT = 8
OOOOOOXOOOOOOXoooooXooooooxooooooXoooooXooooooXooooooXoooooX COUNT = 9
OOOOOXOOOOOXOOOOOXoooooXoooooxoooooXoooooXoooooXoOoOoXoOoOOX COUNT - 10
oooooxooooxoooooxoooo~oooooxooooxoooooxooooxoooooxooooxoooox COUNT = 11
OoOOXOOOOXooooXooooXooooXooooxooooxooooXooooXooooxooooxooooX COUNT = 12
OOOOXooOoXoooXooooxooooXoOoxooooxoooxooooXooooXoooXoOooXoOOX COUN~ = 13
ooooxoooxoooxooooxoooxoooxoooxooooxoooxoooxooooxoooxoooxooox COUNT = 1~
OOOXOOOXOOOXOOOXoooXoooXoooxoooxoooxoooxoooxoooxoooxoooxooox COUNT = 15
OOOXOOOXOOOXooXooo~oooxoooXooxoooxoooXoooXooXooOxooOXOoOXOOX COUNT = 1
OOOXOOOXOOXooOXOoXoooXooxoooXooxoooxooxoooxooxoooxooxoooxoox COUNT = 17
OOOXOOXOOXOOOXOOXooXoooXooxooXoooxooXooXoooXooXooXoooXooXooX COUNT = 18
OOOXOOXOOXOOXoOXoOXoooXooXooXooXooXooXoooXoOXooXooXoOXoOXooX COUNT = 19
OOXOOXOOXOOXOOXoOXOoXoOXoOXooXooXooXooXooXooXooXoOXOOXOOXOOX COUNT - 20
OoXOQXOOXOOXOOXooXoXooXooxooxooxooxooxoXooxooXooxooXooXooXoX COUNT = 21
OOXOOXOOXOXOOXOOXOOXoXooXooXoXooXooxooXoXooXooXooXoXoOXooXoX COUNT = 22
oOXOOXOXOOXOOXOXOOXOXoOXOOXOXOOXOXOOXOOXOXOOXOXOOXOOXOXOOXOX COUNT = 23
OoXOXOOXOXOOXOXOOXOXOOXOXOOXoXooXoXooXoXoOXoXooXoXoOXOXOOXOX COUNT - 2~
oOXOXOOXOXOXOOXOXOOXOXOXOOXoXOOXOXOXOOXOXOOXOXOXOOXOXOOXOXOX COUNT = 25
oOXOXOXOOXOXOXOOXOXOXoOXOXOXOXOOXOXOXooXoXOXooXOXOXOOXOXOXOX COUNT = 26
oOXOXOXOXOOXOXOXOXOXOOXOXOXoXOOXOXOXOXOXOOXOXOXOXOOXOXOXOXOX COUNT = 27
OOXOXOXOXOXOXOXOOXOXOXOXOXOXOXOOXOXOXOXOXOXOXOOXOXOXOXOXOXOX COUNT - ?8
oOXOXOXOXOXOXOXOXOXOXOXoXOXOXooXOXOXOXOXOXOXOXOXOXOXOXOXOXOX COUNT -- ~9
OXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOXOX COUNT = 30
OXOXOXO~OXoXoXoXoXoXoXoXoXoXoXXoXoXoXoXoXoxoxoXoXoXoxoXoXoXX COUNT = 31
OXOXOXOXOXOXOXXOXOXOXOXOXOXOXXOXOXOXOXOXOXOXXOXOXOXOXOXOXOXX CO~NT - 32
OXOXOXOXOXXOXOXOXOXXOXOXOXOXOXXOXOXOXOXXOXOXOXOXOXXOXOXOXOXX COUNT - 33
OXOXOXOXXOXOXOXXOXOXOXXOXOXOXXOXOXOXOXXOXOXOXXOXOXOXXOXOXOXX COUNT = 34
OXOXOXXOXOXXOXOXOXXOXOXXOXOXOXXOXOXXOXOXOXXOXOXXOXOXOXXOXOXX COUNT = 35
OXOXXOXOXXOXOXXOXOXXOXOXXOXOXXOXOXXOXOXXOXOXXOXOXXOXOXXOXOXX COUNT = 36
OXOXXOXOXXOXXOXOXXOXOXXOXXOXOXXOXOXXOXXOXOXXOXOXXOXXOXOXXOXX COUNT = 37
OXOXXOXXOXOXXOXXOXXOXOXXOXXOXXOXOXXOXXOXOXXOXXOXXOXOXXOXXOXX CO~NT = 38
OXOXXOXXOXXOXXOXXOXXOXOXXOXXOXXOXXOXXOXXOXOXXOXXOXXOXXOXXOXX COUNT = 39
OXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXXOXX COUNT = 40
OXXOXXOXXOXXOXXOXXOXXXOXXOXXOXXOXXOXXOXXXOXXOXXOXXOXXOXXOXXX COUNT - 41
OXXOXXOXXXOXXOXXOXXXOXXOXXOXXXOXXOXXOXXXOXXOXXOXXXOXXOXXOXXX CO~NT ~ 42
OXXOXXXOXXOXXXOXXOXXXOXXOXXXOXXOXXXOXXOXXXOXXOXXXOXXOXXXOXXX COUNT = 43
OXXOXXXOXXXOXXXOXXOXXXOXXXOXXXOXXOXXXOXXXOXXXOXXOXXXOXXXOXXX COUNT = 44
OXXXOXXXOXXXOXXXOXXXOX%XOXXXOXXXOXXXOXXXOXXXOXXXOXXXOXXXOXXX COUNT = 45
OXXXOXXXOXXXOXXXXOXXXOXXXOXXXXOXXXOXXXOXXXOXXXXOXXXOXXXOXXXX COUNT = 46
OXXXOXXXXOXXXOXXXXOXXXXOXXXOXXXXOXXXOXXXXOXXXXOXXXOXXXXOXXXX COUNT - 47
OXXXXoxxxxox~xXOXXxXOXxXXoXXxXOXXXXoxXXXOXXXXOXXXXOXXXXOXXXX COUNT = 48
OXxxxoxxxxoxxxxxoxxxxoxxxxxoxxxxoxxxxxoxxxxoxxxxxoxxxxoxxxxx COUNT = 49
~xxxxxoxxxxxoxxxxxoxxx~xoXxxxxnxxxxxoxxxxxoxxxxxoxxxxxoxxxxx COUNT - 50
OXxxxxoxxxx~oxxxx~'~o~xxxxoxxxxxxoxxxxxxoxxxxxox~xxxxox~xxxx COUNT = 51
~XXXXXX~xXXXXXXOXXXXxXOXXXxxxxOxxxxxxOxxxxxxxOxxxxxXOXXXXXXX COUNT = 52
OxXXXXXXOXXXXXXXXOXXXXXX~OXXXXXXXXOXXXXXXXOXXXXXXXXOXXXXXXXX COUNT - 53
oxxxxxxxxXoxxxxxxxxXoxxxXxxXXX~xxxXxxXXXOXxxxxXXXXOXXXXXXXXX COUNT - 54
oxxxxxxXXXXXoxxxxx~xxxxxox~xx~xxxxxxoxxxxxxxxxxxoxxx~xxxxxxx COUNT = 55
oxxxxxxxxxxxxxxoxxxxxxxxxxxxxxoxxxxxxxxxxxxxxoxxxxxxxxxxxxxx COUNT - 56
oxxYXx~xx~xxxx~xxxxxoxxxxxxxxxxxxxxxxxxxoxxxxxxxxxxxxxxxxxxx COUNT = 57
oxxxxx~xxxxxxxx~xxxxXxxxxxxxxxoxxxxxxxxxxxxxxxxx~xxxxx~.xxxxx COUNT = 58
Oxxxx~xxxxxx~x~rxxxxxxxxx-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx~xx COUN'r 59
XXX~XXXXxXxY~XXxxxx~xxxxxx~xxx'~xx~xxxxxxxxxxxxxxx~xxxxxx~x COUNT - 60
~G
-~7-
