COMPUTER CONTROLLED LIGHT WITH CONTINUOUSLY VARIABLE COLOUR TEMPERATURE, COLOUR MODIFICATION, FOCUS AND POSITION

SOURCE LUMINEUSE A COMMANDE PAR ORDINATEUR DE LA TEMPERATURE DE COULEUR, DES COULEURS, DE LA FOCALISATION ET DE LA POSITION

English Abstract

A B S T R A C T

A lighting system is described having an electronic
means for controlling the colour, colour temperature,
magnification and focus in response to predetermined signals
from a computerized system. A wide spectrum light beam having
a wavelength of from 380 nm to 700 nm is passed through a heat
absorbing condenser to control the predetermined colour
temperature thereof and said portion of the beam is separated
into a first colour beam having a wavelength of from 445 nm to
450 nm, a second colour beam having a wavelength of from 555 nm
to 570 nm and a third colour beam having a wavelength of from
525 nm to 535 nm. The separated colour beams are maintained at
substantially equal focal length and the intensity of the
respective colour beams varied in response to an electronic
signal. The colour beams are then combined to form a composite
beam of predetermined colour. The colour and intensity of the
resulting beam is thereby more accurately predetermined.

Claims

The embodiments of the invention in which an exclusive property
or privilege is claimed, are defined as follows:
1. A lighting system for controlling the colour, colour
temperature, magnification and focus of a light beam
comprising:
means for providing a wide spectrum light beam of
predetermined intensity,
means for reflecting that portion of said beam having a
wavelength of from 380 nm to 700 nm through a heat
absorbing condenser to control the predetermined colour
temperature thereof in response to an electronic signal;
means for separating said portion of said beam into a
first colour beam having a wavelength of from 445 nm to
450 nm, a second colour beam having a wavelength of from
555 nm to 570 nm and a third colour beam having a
wavelength of from 525 nm to 535 nm;
maintaining said colour beams at substantially equal
focal length;
varying the intensity of each of said colour beams in
response to an electronic signal and combining said
colour beams to form a composite beam of predetermined
colour.
2. A lighting system as claimed in claim 1 wherein said
means for separating said portion of said beam comprises a
liquid crystal window having means for electronically
controlling the predetermined degree of transmission
therethrough of each of said colour beams.




3. A lighting system for controlling the colour, colour
temperature, magnification and focus of a light beam
comprising:
means for providing a wide spectrum light beam having a
wavelength of from 380 nm to 700 nm;
a heat absorbing condenser for controlling the
predetermined colour temperature of said beam;
a liquid crystal display panel having a matrix of
windows arranged in groupings of three windows, each
passing varying and predetermined amounts of blue light,
red light and green light respectively, the windows of
each said grouping being in such close proximity as to
condense light beams passing therethrough into a single
visible beam;
means for passing said beam through at least one
grouping of windows on said liquid crystal display
panel, and
a lens system for projecting the beams from said
grouping to form a composite beam of predetermined
colour.

Description

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COMPUTER CONTROLLED LIGHT WITH CONTINUOUSLY VARIABLE
COLOUR TEMPERATURE, COLOUR, MAGNIFICATION, FOCUS, AND POSITION
TECHNICAL FIELD
This invention relates to the illumination, in Particular to the
lighting of live stage and theater, as well as film and television.
BACKGROUND ART
The lighting of stage, theater, film and television has in the
past typicallY been done with conventional lights. These lights have
onlY limited capabilities and can generallY perform only one function
Per lisht. This requires a great many lights to achieve the desired
illumination effect.
TYpically~ lights are fixed in a specific location and can
Produce onlY one given colour. The shaPo of the beam that is
projected is normally fixed as well. These elements of Position~
colour, and beam shape are determined when the lighting design is
being carried out. When the lights are installed for the performance,
they are adiusted to Produce the desired effect.
The Position of the light, or for that matter, the Position of
the image thrown by the light, i9 controlled bY the position the light
is mounted on the truss or other supporting memb~r and the alignment
of the light. The colour is controlled bY placing a coloured material
in the Path of the light beam to Produce the desired hue and
saturation. The intensitY of the light beam is generally determined
by a Power control device off stage and seParate from the light
itself. The beam shaPe is controlled by either focusing the beam at
different distances to Produce different degrees of beam divergence,
or bY Placins a gobo or some other template in the P~th of the beam
which alters the shape of the Proiected beam.
When a gobo is used to alter the shaPe of the light be~m, the
image i8 Proiected using v~rying degroes of focw to Produce both
sharp and soft Projected images. The problem with this sYstem is that
in order to get a sharp image at the di~t~nce that you want to
proiect, the image may not be the size that You desire due to the
fixed focal length of the Proiectins lens.
While a large range of coloured materials exist for placement in
the path of the light to alter the colour, these materials onlY change
the huo and s~turation of the light beam but not the colour
temPer~ture of the actùal light source. This is very impor~ant for
the film ~nd television industry, where the cameras are very sensitive
to variations in the colour temPerature of the light 30urce. A
common prob}em is the filming of a scene in an environment where
artificial lighting is required and a n~tural soUrce of lisht alreadY
exists a9 well. The Problem begins when the colour temPerature of the
two light sources are different from each other. This requires that
one of the light sources be filtered to match both the colour
temperature of the other light source and the film as well. This
creates inefficient iight sources and increa~ed costs. Sometimes l~rge
areas such as windows need to be covered with the filter material.
This is done to convert the light coming from a source on one side of
the window into a compatible colour temperature with the light on the
other side of the window.

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A further problem with the-~e coloured materials is that they work
by absorbing all the wavelensths of light except the ones that are
desired to produce that particular colour. The result i9 that the
filter~ absorb the unused wavelengths of light and convert them into
heat, tYpically meltins or discolouring the filter from the heatins
effects. This means that theY have a short life sPan and need
con~tant rePlacing.
A more obvious problem of thi~ form of lisht colourins is that
You can only Produce one colour from the coloured material.
The light sources also Produce a substantial amount of heat.
This intense heat from the lights is very unPleasant for the
Performers on stage and a constant Problem in the close uP world of
television and film, where the heat from all the lights can sPoi
makeup and other heat sensitive effects that have been created.
Since the lights are fixed in a Particular location, they do not
Possess the abilitY to be Pointed at another location during the show.
This increases the number of lights that need to be used during the
Performance.
A partial solution to some of the above Problems is described in
U.S. Pat. No. 4,392,1~7 to ~ornhorst. His sYstem includes a light
which can Produce a number of colours and varY the beam divergence and ~ -
Position of the Projected imaqe. In his sYstem~ the colours are
Produ~ed bY introducing a number of coloured filters into the Path of
the light beam, that instead of absorbing the unused Portion of the
light, reflects it off the surf~ce of the filter. Thi8 helPs to
eliminate some of the heating effects that occur in the filter~ and
increases their life sPan. ~y adjusting the Position of these filters
in the Path of the light beam, a number of colours can be achieved.
The heat from the light source still escapes from the light and lands
on the stege, still causing discomfort and heating the objects in the
Path of the lisht. While this invention can Produce a range of
colours, this method cannot produce a continuous range of colours. -~
A method of Producins a continuous range of colours i9 described
in U.S. Pat. No. 4,535,39~ to Dugre. His system uses three primary
coloured light sources, which he combines using two dichroic mirrors
into a single light beam.
~ hile the basic optical idea is feasible, it is inefficient due
to the extra filtering of the light sources that is required to
Produce the three Primary coloured light sources. If the filtering is
performod usin~ the coloured materials th~t are used on conventional
lights, then this sY~tem will fall Prey to the same heating effects
that ruin these^materi~ls on the conventional lights. This would mean
that the li~ht would fail before the Performance was finished and -you
would constantly need to rePlace the coloured material. Although not
specified in the patent, it is more likely that the same sort of
dichroic filters that are used in the ~ornhorst invention Previously
described, would be used here because of the abilitY to reflect
un~anted w~velengths, which cuts down on the heating of the filters
from this waste !ight. The Problem with these dichroic filters is
that theY are heat ~ensitive. The heating effects from the high power
light sources will cause a temperature induced colour drift in the
Primary filters. This will vary dePending on the Present intensity of
the individual lights. This will make it difficult, if not imPossible
to accurately Produce a desired colour at any given time due to the
unknown degree of colour shift that has occurred at that point in
time.




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2~ L5883

If the light sources are left on constantlY, the colour shift can
become quite substantial.
The heat will also cause aging of the filters, which will show
up as a Permanent shift in colour. This will necessitate the frequent
replacins of these rather exPensive filters.
The means of control of the intensity of the three Primary light
sources, and the indecisiveness of the exact amount of the three
primary colours that are being added, makes the control of the colour
temperature of the light, not to mention, the exact colour being
produced, imPossible. This form of controlling the light will allow
onlY course changes in colour, and would not achieve much more of a
range of colours than the Bornhourst invention Previously mentioned.
However, since an additive method of colour generation is being used,
rather than the previouslY mentioned method of discrete filters, a
continuous range of colour can be Produced~
A further Problem with the Dugre invention is that the oPtical
sYstems he has described will not produce a single clean coloured
light beam. The length the light travels from each of the three light
sources is different, and therefore the angle of divergence of the
three light beams will be different. This causes the comPosite beam to
aPPear as three overlapPing cones of light when it reaches the stage.
AnY shadow Produced on the stage bY a beam of light from this optical
system will not Produce one distinct shadow, as would a single
coloured beam, but rather a number of seParate and differentlY
coloured shadows behind the performer on stage. This is a distracting
side effect and not really suitable for use in illumination of stages
or other types of Performances. A true single beam of light would
produce only one clean shadow, with no colour separation occurring.
The heat from the light sources is still able to reach the stage
in this oPtical design causing all the above mentioned Problems.
None of this known art teaches a light that has a continuouslY
variable colour temPerature, a9 well as continuously variable colour,
which can be rePeatedly Produced~ and further, which can Produce a
variable sized image, that can be focused over a large range of
distances, and carries no heat in the light beam falling on the stage.
DISCLOSURE OF THE INVENTION
The Present invention Provides a lighting sYstem~ which includes
at least one light which has a directable beam of light. The colour
temperature, colour, magnification and focus of which can be
continuously varied, and has no heat remaining in the light beam. A
pivoting mechanism i~ Provided to Point the light beam at anY location
on the stage. The CPU and control electronics receive and transmit
information on a two way fiber optic communication link.
In accordance with another asPect of the invention, a method of
producing the coloured light beam is Provided. One such method is via
the use of three wide sPectrum lisht sources. These three light
sources have the heat and ultraviolet light removed from the beams
which are then condensed down to a sharPly defined disk to be
proiected by the front lens system. After being condensed, the three
beams strike a sPecial mirror. T~ree such mirrors exist, one for each
beam. Each mirror reflects a sPecific ~ortion of the visible lisht at
an angle of 90 degrees from the original path. The three mirrors are
positioned in such a way that the three reflected beams are coincident
on each other.



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This forms a new comPosite beam of lisht, the colour of which i9
determined bY the intensitY of the three beams before they reach the
reflectins mirrors. The intensity of the light sources is determined
by the control electronics. This control mechanism has sufficient
precision as to make Possible very minor and exact adjustments in the
intensity of each light source.
In accordance with Yet another asPect of the Present invention, a
second means of Producins a variably coloured light beam is Provided.
This method uses onlY one wide spectrum light source which does not
require variable intensity control. The light from this source has
any heat and ultraviolet light removed from the beam and is then
condensed down to a sharP disk to be further Processed bY the oPtical
system. This light beam now enters an electronic colour generating
prism. This Prism seParates the single light beam into three equal
light beams. These three light beams Pass through their own liquid
crystal windows. The windows control the intensitY of the light
beams. After the intensitY is determined, Portions of the three white
light beams are recombined to form a sinsle coloured light beam which
emerges from the prism. The recombining of the lisht is Performed bY
the same tyPe and arrangement of mirrors that are used in the first
method of colour senerating. The difference being that now the
mirrors are Produced bY surfaces inside the Prism. The control
electronics associated with the liquid crystal windows affords
sufficient precision in the control of the lisht transmittins abilitY
of the liquid crystal as to allow the same Precise adjustments in the
intensity of the three beams of light.
In accordance with Yet another asPect of the invention, a third
method of Producins a coloured light beam is presented. This method
uses a single white light source, which has anY heat and ultraviolet
light removed from the light beam, and is condensed to flood a liquid
crYstal panel with light. This liquid crYstal Panel contains a matrix
of tiny liquid crystal windows. The intensitY of each window can be
individuallY controlled. The window9 are arransed into srouP9 Of
three in such a w~Y that each member of the grouP transmits a
different Primary colour. Since the windows aro 90 tinY~ and they are
close to each other, they aPPear as one single sPot~ the colour of
which is determined bY the intensitY of the light leaving each window
in the srouP.
In accordance with Yet another asPect of the invention, a CPU i8
Provided~ which exchange9 information with the main control comPuter
(not covered in this document) running the lighting sYste~. The
computer inside the light sends information to the control electronics
which determine~ wh~t colour is being Produced~ what colour
temperature the light beam has, where the light beam is pointing, the
size of the final image, the dsgree of focus, and any other oPtionally
included functions.




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3RIEF DESCRIPTION 0~ THE DRAWINGS
The following illustrations maY helP to clarify the description
of the invention.
FIG. la-c are three top views of the light which utilize the three
embodiments of the light source~ forming the Present invention;
FIG. 2a-c are views of the three embodiments of the coloured light
source and control electronics formins the Present invention;
FIG. 3a-b are views of the optional gobo wheel and shutter mechanism
fonming the Present invention;
FIG. 4 shows the Pan and tilt mechanism forming the Present invention:
FIG. 5 is a block diagram of the electronics that remain the same
through all three embodiments of the light forming the Present
invention; and
FIG. 6 is the front lens sYstem used in the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, wherein like reference characters
designate like or corresponding Parts through several views, FIG. la-c
illustrntes the light (10) forming the Present invention. The Present
form of the main control computer can direct over 1000 of these, or
other conventional lights. The light (10) forming the Present
invention can be used for live theater, stage, television, or film
lighting, both in and out of doors.
The main control computer is resPonsible for storing all the
information needed to direct the lights to Produce whatever lighting
effect that is desired. All light show designing, Previewing, and
direction, is c~rried out on the main control ComPuter. The
infonmation that is needed to instruct a light (10), is sent to the
light via the fiber oPtiC communication link (60) from the main
control computer.
Referring now to FIG. 5, the organization of the control board
inside the light (10) forming the present invention will be discussed.
The infonmation to instruct the light (10) is received via the fiber
optic -link (60). When the light (10) is in a non-active state, the
informntion is simPly echo~d via the transmitter (504) back out into
the fiber oPtic loop (60). When the light (10) receives instructions
to go online~and become active in the loop, the automatic bridge (502)
between receiver (503) and transmitter (504) is broken, and the
advanced data-link controller (ADLC) chip (500) takes over the
echoing Proces~. The ADLC chiP (500) is used in the loop
configuration mode and offers a very high degree of data transmission
integrity. The ADLC (500) uses the `'~dvanced Data Communication
Control Procedure" (ADCCP) Protocol when communicating, and thus
handles all address control, error detection, and information
formatting. The use of the ADLC (500) along with the fiber optic
connecting cable (60), Provides a virtually error free data link with
the main computer.

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The fiber oPtiC cable (60) is immune to electrical noise which
plasues other serial communication method~, and with the ADLC (500)
advanced communication Protocol, insures that a light never resPonds
to an errored transmission. The second advantage of using this
combination of the ADLC t500) and the fiber optic cable (60), i9 that
the data transmission rate can be high enoush that two waY
communication can be carried out on the data link (60). This means
that the lights (10) can rePort status informdtion back to the main
control comPUter bY simply passins it along the data loop (60). The
ADCCP Protocol ensures that each light (10) only resPonds to the
packets of information that were addressed to it and Provides a
mechanism for the interleaving of information Packets transmitted from
the lights (10) in between the information Packets from the main
control comPuter. This helPs insure the reliabilitY of the entire
lighting sYstem~ since if a light (10), where to detect a malfunction
via the monitoring circuits (501), the light (10) would be able to
instruct the main control comPuter of the problem and shut itself
down. The main control comPuter would then reorganize the lighting
cues, and substitute a redundant, functioning light (10) into the
light show, instead of trying to use an alreadY malfunctioning light
(10). In this manner, even if a light bulb were to burn out, there
would be no interruPtion of the light show on stage, Using the ADLC
(500), the light (10) can be instructed to resPond to different
addresses while the show i9 running. This allows any light (10) to
instantly change the address it responds to, thus m~king substitutions
very easY to accomplish.
Still referring to FIG, 5, the CPU (512) is resPonsible for
overseeing all the function3 that are being carried out by the light
(10). All functions of the light (10) are monitored by a failure
detection circuit (501). Every aspect of the light that can be
controlled is monitored bY this circuit. This enables the light (10)
to Pick uP on any malfunction immediately, and shut itself off before
any disruPtion of the light show can take Place. As soon as the error
i9 detected, the main control comPuter i9 informed, and the oPerator
can take aPpropriate action. Even the CPU (512) is monitored by a
failure circuit. The light (10) has a one second count down timer
(514). During the normal course of running Prosri~ms~ the CPU (512)
will reset this timer (514) before it reaches one second. If however
the CPU (512) ha~ malfunctioned, the timer (5i4) will reach one second
before the CPU (512) can reset the timer (514). UPon reaching one
second, the timer (514) activates a master reset circuit (513) which
turns off the light (10) and takes the light off line. If the CPU
(512) is functioning correctly after this reset, then the light (10)
wiIl put itself back on line and continue running lighting sequences.
However, if the CPU (512) fails to show that it is running correctly,
then the main control computer will substitute a redundant light (10)
to continue the light show. The Programls for the CPU (512) are in the
program memory (515). The Prosrams stored here are resPonsible for
all the functions that the light (10) can Perform. The storage memory
(516) is used for temPorary storase of information as it is sent and
received, as well as intermediate values of calculations. The
lighting instructions come in through the receiver (503) and are
stored in the storage memorY (516). Here theY are decoded and
exPanded using Programs stored in Program memory (515).




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The CPU (512) then Prepares in the storase memory (516) the
values that need to be aent to the variou~ control register~ which
control the functions of the light (10). EverY feature of the light
(10) i8 run by loading a set of values into a control register that
corresPonds with that function. Once the control registers are loaded,
the control electronic~ (14) take over the function and Perform it
automaticallY. This relieves the CPU (512) from alot of extra
overhead that would degrade the Performance of the light (10). The
CPU (512) can monitor the control electronics (14) oPeration~ via the
monitoring circuits (501). In this way the CPU (512) will know if the
light (10) is performing the functions the waY that the light (10) is
supposed to be. The main function of the CPU (512) is then to decode
and Prepare instructions for the control electronics (14), and to
detect any mRlfunction in the light (10) and to rePort it to the main
control computer. The advantage of each light (10) having a built in
computer makes it possi~le for the light (10) to Perform lighting
effects that are far more complicated than anY conventional light can
perform, and in manY cases, effects that are impossible with any other
type lighting system.
Still referring to FIG. 5, there are still several portions of
the electronics which do not change between the three embodiments of
the control electronics. TheY are the Power supply (13), fan control
(20), pan function control (21), tilt function control (22), gobo
control (23), shutter control (24), and lens control (25). The light
(10) is Powered bY a single 110 vac line. The power supplY (13)
conditions the 110 vac and Produces all the other voltages that are
required bY the light (10).
There is a high degree of sPecial filtering that is carried out
bY the Power 8UPply as well. First the input to the power 8UPply is
Protected bY a series of transient arrestors (12). These Protect the
electronics inside the light (10) from lighting strikes on the 110 vac
line. After lightning protection, the 110 vac line is filtered with
an EMI choke (19). This filter (19) Prevents any Electro MasneticallY
Induced noise from entering the power supplY lines feeding the CPU
(512) or the control electronics (14). Noise of this type could cause
an error to occur, 80 its eliminition from the power ~uPply is
nece~sarY to ensure the reliabilitY of the lisht (10). The suPPly
lines feeding the CPU (512) and the control electronics (14) are also
filtered individuallY everY few inches on the Printed circuit board as
well~ This Prevents any local voltage disturbances from causing
problems with the other electronic comPonents in the circuit.
FinallY~ the CPU (512) and the control electronics (14) are batterY
(18) backed uP. This way, should there be a power failure, the
batterY (18) will continue to Provide power for the vital portions of
the light (10). Then, when the Power i9 restored, the light (10) will
not have lost any data, and still be completely readY to Perform the
lighting tasks.
The pan function (21) is controlled by three registers, pan sPeed
(540), pan direction (541), and steP count (542). The values stored
into these three registers will control which direction the lisht (10)
will Pan~ how fast the pan will be, and how fàr to Pan.
Referring now to FIG. 4, the panning is Performed bY a stePPing
motor (543), controlled bY the signals derived from the pan control
electronics (21). The stePping motor is connected to a gear reducing
mechanism (544), which causes the bodY of the light (10) to rotate
horizontallY about supportins shaft (520).




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Referrins asain to FIG 5, the tilt function (22) is controlled in
a similar waY with the three registers tilt sPeed (550), tilt
direction (551), and step count (552).
Referring now to FIG. 4, the tilting i9 Performed by a stePping
motor (553), contrslled bY the sisnals derived from the tilt control
electronics (22). The stePPing motor i9 connected to a gear reducins
mechanism (554), which causes the bodY of the light (10) to rotate
vertically about supporting shaft (530).
It can now be understood that the light (10) can be moved in the
horizontal plane (panned) as well as in the vertical Plane (tilted) to
Point to anY location on the stage or surroundins area.
Referring back to FIG. 5, the optional gobo wheel (35~ is
controlled bY the register~ wheel Position select (560), gobo rotation
sPeed (561), sobo rotation direction (562), and rotation steP count
(563). The wheel position register (560) controls the rotation of the
gobo wheel (35) to Place the desired gobo (36,37,38,39) in the path of
the light beam. The gobo wheel (35) is rotated bY a steppins motor
(564). The other three registers control the direction, sPeed~ and
length of time the gobo (36,37,38,39) is rotated in the light beam.
Referring to FIG. 3a, the individual gobos (36,37,38,39) are rotated
by the same stePping motor (565). This abilitY to rotate a gobo
(36,37,38,39) while in the light beam enables unigue sPecial effects.
One such effect, impossible with conventional lights used in industry,
is a kaleidoscoPe effect. This is Produced bY taking ~ gobo (36)
which produces a small wedge of light and rotating it in the light
beam f~st enough that it Produces what aPpears to be a continuous
circle of light due to persistence of vision. ~Y changing the colour
of the light beam as the wedge passes different Positions in the
circle, a multicoloured circle is Perceived bY the eye.
Referring now to FIG. 3b, a stroboscopic effect can be generated
by the shutter mechanism (30) associated with the gobo wheel (35)
inside the light (10). The shutter l30) consists mainly of a disc the
same size as the sobo wheel (-35), vith holes that corresPond in size
and location with the holes in the gobo wheel (35). The gobo wheel
(35) and the shutter wheel (30) are mounted coaxi~lly. When the holes
in the two wheels (30,35) are aligned correctly, the light beam can
P~99 through both wheels (30,35). 9ut when the shutter wheel (30) has
been rotated by a stePpins motor (572), the holes will no longer line
up and the light is blocked off. 9y controlling the rotation of the
shutter wheol (30), a strobe light effect can be produced.
R~fR~ing baG~ to Fl~. 5, the method of controlling the shutter
wheel (30) is bY the control registers wheel speed (570), and wheel
step count (571). These two control registers are resPonsible for the
synthesizing of the motor drive signals that rotate the shutter wheel
(30) the exact amount, and at the correct sPeed, to Produce the strobe
effect.
Still using FIG. 5, the lens sYstem (50) is controlled bY the
control registers actuator #1 direction (580), actuator #1 speed
(581), actuator #1 steP count (582), actuator #2 direction (583),
actuator #2 speed (584), and actuator ~2 steP count (585). The
control registsrs (580,581,582) Produce signals that control -linear
actuator #l (588), which is responsible for moving lens element #2
(52). The control registers (583,584,585) are resPonsible for
producing signals that control linear actuator #2 (589), which ~oves
lens element #3 (53).




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Referrins now to FIG. 6, The imase to be proiected is reflected
into the front lens system bY a first surface mirror (217). The front
lens sYstem (50) is comprised of four lens elements (51,52,53,54).
Two of the lens elements (51,54), are fixed in Position~ while the
other two len3 elements ~52,53), are movable. The first lens element
(51) picks uP the image of one of the sobos (36,37,38,39) or the
liquid crystal Panel (103) and projects it with a reduced image size
to a fixed Point within the lens sYstem (50). The next two lens
elements (52,53), work together as i duplet lens. The sPacins of the
two lens elements (52,53) is controlled bY linear actuator ~1 (588).
This variable distance between the two lens elements (52,53) in the
duPlet causes the duplet to have a variable effective focal lensth.
The second linear actuator (589) controls the position of the duPlet
between the first and last lens elements (51,54). By manipulating
both the effective focal length of the duplet, and the position of the
dupl~t~ a va~iable focu8, variable magnification lens can be achieved.
The reduced image from the first lens element (51) is Picked up and
magnified bY the second and third lens elements (52,53) and Proiected
to a Point inside the lens sYstem (50). The position of the Projected
image from the second and third lens elements (52,53) determines where
the image will be focused when Proiected bY the final lens element
(54). The image picked uP by the final lens element (54) is magnified
further, and Proiected to the stage. With the correct positioning of
the second and third lens elements (52,53), the front lens system (50)
can Produce a light beam whose angle of divergence can be varied from
4 degrees to 64 degrees. Furthermore, due to the nature of the lens
system (50), the beam can be focused from a distance of at least 15
feet, to infinitY. Due to the variable focal length and Position of
the second and third lens elements (52,53), a variety of
magnifications of the image of sobos (36,37,38,39) or the liquid
crYstal panel (103) can be Produced at the final focal Point of the
lens system (50). This differs from the art Previously described,
where the image size is a function of where the image is focused, and
are not indePendentlY controlled as described above.
Referring to FIG. la, the fir~t method of Producins the coloured
light beam will be discussed. White light Produced by a wide spectrum
source (71) is reflected at an angle of 90 degrees bY a mirror (220).
This mirror (220) reflect~ light between the wavelengths of 380 nm. to
700 nm. This essentiallY removes all short wave ultraviolet and
infrared radiation. The light reflected from this mirror (220) will
have almost all of the heat and harmful ultraviolet radiation removed.
This light will Produce virtually no heating effects or ultraviolet
light related fading effects. The light reflected from this mirror
(220) is condensed bY a heat absorbing condonser lens (80) which
removes any heat that maY have been reflected by the mirror (220) and
projects this light to illuminate one of the gobos (36,37,38,39).
Before the light reaches the gobo wheel (35). the light is reflected
degrees by a mirror (201). The mirror (201) is Placed in such a
way that the light reflected from it will fall on the selected gobo
(36.37.38,39). The mirror (201) reflects a narrow band of wavelengths
which peak between 445 nm. and 450 nm. The wavelength boundaries that
the mirror (201) reflects corresPonds to the wavelengths that
stimulate the recePtors in the human eye which have been pigmented to
respond to the blue colours. Therefore, the only lisht reflected bY
the mirror (201) is light that the blue receptors of the human eYe
will Perceive.

2Q~ 33


This mirror (201) will transmit all other wavelensths of lisht
that strike it. Since light falling on this mirror t201) is either
reflected or transmitted, and the light falling on the mirror (201)
has no infrared energy, the heating effects and consequent colour
drifts are non-existent. Likewise, fading from ultraviolet lisht has
been eliminated as well.
Next, white light from a second wide 3pectrum source (72) is
reflected at an angle of 90 degree~ off of another mirror (221). This
mirror (221) has the same Properties and Performs a similar task to
the first mirror described (220). The light reflected from this
mirror (221) Passes through a heat absorbing condenser lens (81) which
performs a similar task as the Previous lens (80). The light leavins
this condenser lens (81) is reflected 90 degrees bY a mirror (202).
The reflected light from this mirror (202) falls on the first colour
mixing mirror (201) which passes the light without disturbance. Thi~
second colour mixing mirror (202) reflects a narrow band of
wavelengths which peak between 555 nm. and 570 nm. The wavelength
boundaries of this second colour mixing mirror ~202) corresPond with
the wavelengths that stimulate the receptors in the human eye which
have been Pigmented to resPond to the red colours. Therefore, the
onlY light reflected bY this second colour mixing mirror (202) is
light that the red recePtors of the human eye will perceive. This
second colour mixing mirror (202) will transmit all other wavelengths
of light that strike it. As with the first colour mixing mirror
(201), there are no heating or fading effects that occur.
Next, white light from a third wide sPectrum source (73) is
reflected at an angle of 90 degrees off of a third mirror (222) which
has the same Properties and performs a similar task to the other two
mirrors (220,221) Placed after the light sources (71,72). The light
reflected from this mirror (222) Passes through a heat absorbing
condenser lens (83) which performs a similar task to the other two
heat absorbing condenser lenses (80,81). The light leaving this
condenser lens (83) is reflected 90 degrees by a third colour mixing
mirror (203). The reflected light from this third colour mixing
mirror (203) falls on the second colour mixing mirror (202) which
passes the light without disturbance on to the first colour mixing
mirror (201) which also passes this light without disturbance.
The third colour mixing mirror (203) reflects a narrow band of
wavelengths which Peak between 525 nm. and 535 nm. The wavelength
bound~ries of this third colour mixing mirror (203) corresPond with
the wavelenqths that stimulate the recePtors in the human eYe which
have been pigmented to resPond to the green colours. Therefore, the
onlY light reflected bY this third colour mixing mirror (203) is light
that the green recePtors of the human eye will Perceive. This third
colour mixing mirror (203) will transmit all other wavelengths of
light that strike it. As with the Previous two colour mixing mirrors
(201,202), there are no heating or fading effects that occur. The
three colour mixing mirrors (201,202,203) are arranged in the order of
blue (201), red (202), green (203), to maximize the range of
intensities available from the white light source. The white lisht
source (70) has a smaller proPortion of blue light making up the white
light beam than it does red and finally green. Arranging the ~olour
mixing mirrors (201,202,203) in the thi~ order, obtains the greatest
efficiency from the white light source (70) since the blue light
pas~es through the least number of glass surfaces, followed by the red
light and finally the green light.




....~
.
, ;.; . :

2!~S8~1~

Each glass surface that the lisht must Pass through reduces the
efficiency bY a ~mall percentase. Thi9 arrangement of the colour
mixins mirror~ (201,202,203) Produces an almost equal balance of the
three ranges of colour being mixed. The light (10) sYnthesizes
different colours by stimulating the same Proportions of receptors ir.
the human eYe as a Particular colour of monochromatic colour would.
This is an easY task since the wavelensths that the colour mixins
mirrors (201,202,203) reflect match the wavelengths that the receptors
in the human eYe respond to. All that i8 needed is to control the
intensity of the three white light sources (71,72,73) therebY
controlling the Proportions of the receptors that are being
stimulated. The main computer knows the sensitivitY of the colour
receptors in the human eye and the sPectral comPosition of the white
light ~ources (71,72,73). This information is combined to calculate
what inten~itY of each white light source (71,72,73) is needed to
produce the same Proportions of stimulation in the eye as the desired
colour would. This information, along with the desired overDll
intensity of the Perceived lisht, is sent to the lisht (10) which uses
thi~ information to set the intensitY of the light sources (71,72,73)
accordingly. This setting takes into account the varYing colour
sPectrum of the white light sources (71,72,73) at various intensities,
and uses a closed looP feedback system to ensure that the Proper
ratios of light are Produced to achieve the result desired. Since the
colour mixing mirrors (201,202,203) reflect the light that matches the
recePtors in the eye, there is a direct correlation between the light
beam exiting the light (10) and the recePtors that the light will
stimulate. This Provides an very accurate method of simulatins anY
desired wavelength of light. Care has been taken to ensure that the
length of the path between all three lisht sources (71,72,73) to the
gobo wheel (35) is equal. This ensures that the degree of divergence
of all three beams will be the same. Then, when the three beams
combine, there is no difference in the way that the light beams will
focus and project. This eliminates any fringing effects in the
shadows cast bY obiects on stage. The light beam leaving the light
(10), is a crisP beam which apPears as a single monochromatic light
beam, leaving only one clean shadow. Previous art, while being able
to produce coloured effects, cannot accuratelY and rePeatedly Produce
a desired colour with the control and accuracY of this method.
There are several advantages to this tyPe of colour control.
First, this method of control affords the user with the abilitY of
sPecify a colour by wavelength. In Previous art, the user would have
to adjust knobs until a colour resembling what theY want aPpears on
stage. This *ew method allows You to sPecify the wavelength of the
light on a comPuter screen without having to adiust knobs or make
visual determinations of the colour. A major advantage of this is for
lighting designers who frequently design their lighting without even
turning on a light. The colour theY want is identified bY a number
corresponding to a coloured filter mnterial. They usuallY can name
the colours they want from their own memory. The main comPuter knows
all the popular filters bY number. The user can therefore just name
the filter desired, and the main comPuter knows what wavelengths of
light need to be passed in what proportions to produce that colour.
The second main advantage of this method of control of the
colour, i8 that very minute adiustments in the colour can be made.




. . .

. , .
, . .

. . .

2~)~5~3~33

_ .

Many of these smaller adiustments will not be seen by the eye,
due to the automatic white balance adjustments made bY the eye, but
will be obviouR when recorded on film. These minute adiustment~ are
actually changes in the colour temPerature of the light. When we look
at several different colour temperature sources of white light, we see
them all aR white. This i9 because of the automatic white balancins
the eye Performs. Film however cannot change the waY it i8 balanced
for white light. Therefore the different colour temPerature light
sources will photograPh as different colours. The light (10) has the
ability to make small and precisely controlled colour changes which
sive the light (10) the ability to alter the colour temPerature of the
light beam leaving the light (10). This is a very big advantage for
lightins in the film industrY~ since now the desisner can not onlY
call uP sPecific colour filtration by name, but can also specifY the
colour temPerature of the light that the filter is Placed in front of.
The designer simply tells the main comPuter what colour temperature
light source i9 desired, and what tYpe of filter is to be used with
that light source. The main comPuter takes all the information into
account, and sends the instructions to the light (10) which Precisely
controls the light sources (71,72,73) to Produce the desired result.
Referring now to FIG 2a, the first embodiment of the control
electronics will be discussed. The first embodiment of the control
electronics (15) controls the intensitY of the three white lisht
sources (71,72,73). These three lights (71,72,73) are high output,
low voltage incandescent bulbs. By using lower voltage bulbs, and
having a closed looP feedback system, line voltage fluctuations of uP
to 30% can be tolerated with no degradation in the performance of the
light (10). The control circuit (15) is duPlicated for each of the
three light sources (71,72,73). The control electronics (15) for each
light (70) consists of six main Parts. These are the frequency
division circuit (150), the intensitY control circuit (151), the
intensity auto increase/decrease circuit (152), intensitY change sPeed
control (153),the interruPt generating circuit (154), and the
feedback control circuit (155). The control electronics (15) has a
very high resolution of control and can accuratelY produce 16,777,216
colour temPeratures~ ew h colour temPerature having a range of
16,777,216 colours. The frequencY division circuit (150) is
responsible for the determination of the colour temperature of the
light beam. This circuit controls the maximum intensity that a light
source ~70) can achieve and the re~olution of the power control of
that light source.
By controlling the maximum intensitY~ and the resolution of the
remaining portion of the power enveloPe, the number of colours that
can be Produced with that colour temPeratUre is maintained, while at
the same time, the colour temPerature of the light beam can be
modified. The determination of a specific colour is carried out bY
the intensitY control circuit (151). This circuit i8 responsible for
gating a TRIAC power controller (156) at the Precise point in time to
deliver the correct Percentage of Power to the bulb (70) to achieve
the desired colour. This Percentage will vary as a function of the
desired colour temPerature of the fini3hed light beam and the sPectral
comPosition of the source (70) at the pre~ent intensitY. Both of
these factors are taken into account and handled automatically bY the
frequency division (150) and intensity control (151) circuits. EMI
filtering is used to eliminate any electrical noise which was produced
by the gating circuit (156).




~ .. .. :. . ~ . .............................. .
.

The desired intensity can be loaded directlY into the intensitY
resister (159) in the intensity control circuit (151) or automaticallY
adju~ted bY the intensity increase/decrease circuit (152). This
circuit i~ controlled by loadins the new intensitY into the control
register (157). The sPeed of the change from one intensity to another
is controlled bY the sPeed control circuit (153). The rate of change
in intensitY is loaded into the speed control register (158). When
the bulb has reached the new intensity, an interruPt i9 sent to the
CPU (512) by the interruPt generating circuit (154). In this manner,
the program can keep track of which bulb (71,72,73) has reached the
desired intensitY. The automatic feedback circuit (155) keeps the
intensity of the light source (70) at the correct level bY directly
manipulating the intensitY increase/decrease control circuit (152), or
the frequency division control circuit (150). This ensures that when
the CPU (512) loads the control circuit (15) with the desired colour
temperature and intensitY information, accurate results are
maintained.
Refering now to FIG. lb, the second method of Producins a
coloured light beam is discussed. White light from a wide spectrum
light source (74) is reflected 90 degrees bY a mirror (223) which
reflects light between the wavelengths of 380 nm. and 700 nm. and
transmits all other wavelengths of light. This essentially removes
all ultraviolet and infrared light from the white light beam leaving
the light source (74). The light reflected by this mirror (223)
passes through a heat absorbing condensor lens (83) and enters the
electronic colour generating prism (110). This Prism (110) is
responsible for generating the coloured light beam which will be
projected bY the light (10). The light beam entering the prism (110)
first encounters a sPecial mirror (207) which redirects 33% of the
light on a path 90 degrees to the original Path that was being taken.
This reflected light falls on a liquid crYstal window (91). The
amount of light transmitted by this window is determined by the
control electronics (16). AnY light leaving this window is reflected
degrees by a first surface mirror (210). This reflected light is
reflected 90 degrees again bY a another first surface mirror (211).
The refelected light from this second first surface mirror (211) falls
on a sPecial colour mixing mirror (203). This mirror reflects at an
angle of 90 degrees, a narrow band of wavelength~ which Peak between
525 nm. and 535 nm. These wavelengths corresPond to the wavelength~
which stimulate the recePtors in the human eye which have boen
pigmented to resPond to the green colours. All other wavelengths of
light striking this mirror (203) are transmitted straight through
without disturbance.
The reflected light from this colour mixing mirror (203) is
undeviated any further and exits from the prism (110) after passing
through ~the other two colour mixing mirrors (202,201) w~.ich have no
affect on the green light beam. The other 66% of the light which was
not reflected bY the first beam sPlitting mirror (207) now encounters
a second beam splitting mirror (208). 50S of the light striking this
second beam splitting mirror (208) is reflected 90 degrees while the
remaining 50% travels on undisturbed. The reflected 50% equals 33~ of
the original light beam from the light source (74) and this reflected
beam strikes a liquid crYstal window (92). The light transmitting
proPerties of this window is controlled by the control electronics
(16). AnY light transmitted by this window (92) is reflected 90
degrees bY a first surface mirror (212).



: . .

~` . ;., '~ .
.~ ..
. ......................................................... .

2~5~38~

The reflected lisht from thi-~ mirror is reflected 90 desrees bY
another first surface mirror (213). The light reflected from this
second first surface mirror falls on the second colour mixing mirror
(202). This second colour mixing mirror (202) reflects at an angle of
90 degrees a narrow band of wavelengths which Peak between 555 nm. and
570 nm. which corresponds with the wavelensths that stimulate the
receptors in the human eYe which have been Pigmented to respond to the
red colours. All other wavelengths of light are transmitted without
disturbance through this second colour mixing mirror (202). The light
leaving this second colour mixing mirror (202) Passes undisturbed
through the last colour mixing mirror (201) without being disturbed
and exits the colour generating prism (110). The 50% which was not
reflected bY the second beam sPlittins mirror (208) comprises the
final 33% of the original light beam from the light source (74). This
light encounters a liguid crYstal window (93). The light transmitting
Properties of this window (93) being determined bY the control
electronics (16). Any light leaving this window (93) is reflected 90
degrees bY a first surface mirror (214). This reflected light is
reflected 90 degrees two more times by a Pair of first surface mirrors
(215,216). This serves to reroute the light beam 80 that it lands on
the remaining colour mixing mirror (201). This final colour mixing
mirror (201) reflects at an angle of 90 degrees a narrow b~nd of
wavelengths which Peak between 445 nm. and 450 nm. which corresPonds
to the wavelengths which stimulate the recePtors in the human eYe that
have been pigmented to resPond to the blue colours. This final colour
mixing mirror (201) will transmit all other wavelengths of light
without disturbance. The light reflected by the final colour mixing
mirror (201) exits the colour generating Prism (110). It can now be
seen that the single white light source (74) has been broken down into
three equal light beams, whose intensity is electronic~lly controlled
by the light transmission Properties of the three liquid crystal
windows (91,92,93). The three intensitY modified beams of light are
routed through three different paths which ensure that all three light
beams travel the same length before the three beams are recombined and
leave the Prism (110). The method of sYnthesizins colours is quite P
simular to the first method of producing the coloured light beam with
the major differences being that only one light source is required,
and the light source does not require intensity control, thereby
making it easier to control the colour mixing Process. The main
similarity is the use of the three colour mixing mirrors
(201,202,203).
This mixing system is more efficient then the systems used by the
Previous art, which required three seParate sources of white light
which further needed to be filtered to seParate out the primary
colours and then combine the three primarY colours into a single beam.
This new system simPly reflects onlY the portions of the sPectrum
which need to be combined to produce the desired colour. After
leaving the Prism (110), the coloured light beam either illuminates
the oPtional sobo wheel (35), or is simPlY Proiected by the light
(10) .




, . ;. ~ . ............... .
.,;-.:,, .. : ~

2~5883

Refering now to FIG. 2b, the second embodiment of the control
electronics will be discussed. The control electronics (16) consistR
mainlY of six circuits. These six circuits exist for each of the
three liquid crystal windows (91,92,93). The six sections of the
control circuit are the colour temperature resister (170), intensity
register (171), the inten~itY increase/decrease register (172), the
intensity chanse sPeed control resister (173), the interruPt
senerating circuit (174), and the liquid crystal waveform generating
circuit (175). The value~ corresponding to the desired colour
temperature and colour are loaded into the appropriate registers
tl70,171). These two registers (170,171) are combined to Provide the
information to the waveform generating circuit (175) which sends the
control signAls that determine the light transmitting proPerties of
the liquid crystal window (90). Each control circuit is identical and
controls one of the liquid crYstal windows (91,92,93). The white
light source (74) requires onlY on/off control and this i9 done during
the zero crossing of the Power supply feeding the light source (74).
This zero crossing control of the power eliminates anY electrical
noise that would otherwise be Produced during the power control and
eliminates any need for filtering of the power lines suPplying the
light source (74). The onlY other control that is Performed is the
closed loop feedback of the light source (74) via the monitoring
circuit (501). This feedback eliminates anY fluctuation in the Power
lines supplying the light source (74) and Prevents these fluctuations
from effecting the lights Performance. Since the light source (74)
does not require intensitY control, there is no need to use an
incandescent light source with this method of colour generation, and
other high output light sources can be used insteAd.
The resolution of control of the colour temperature and the
colour is the same as the first embodiment of the control electronics.
Refering now to FIG. lc, the third method of producing the
coloured light beam will be discussed. White light from a wide
sPectrum light source (74) is reflected 90 degrees by a mirror (224)
which reflects light between the wavelengths of 380 nm. and 700 nm.
and transmits all other wavelengths of lisht. This essentiallY
removes all ultraviolet and infrared light from the white light beam
leaving the light source (74). The light reflected by this mirror
(224) Passes through a heat absorbing condensor lens (84) and
illuminates the liquid crystal disPlaY Panel (103). The Panel (103)
consists of a matrix of tiny liquid crystal windows. These windows
are arranged in grouPs of three. In each group of three, one window
will Pass v~rYing amounts of blue light. Another window, in this
group of three will pass varying amounts of green light, and the third
window in this grouP of three will Pass varying amounts of red light.
These windows are 90 small that theY aPPear to the eye as one small
point of light, and essentiallY mix toqether to become one single
colour. The image formed bY all the grouPs of windows (known as
pixels) is Proiected bY the front lens system. The gobo wheel (35)
and shutter mechanism (30) are no longer required to modifY the light
beam in any waY since the same effects can be accomplished by
controlling the Pixels on the liquid crYstal display (103) dirsctlY~
This oPens up a new dimension in lighting. Now gobos are no longer
needed to shape the light beam. Instead, the desired Pattern can be
drawn bY the CPU (512) directly on the liquid crystal display (103).




'. ' , ~ . ,

~; 2Q~Ls883

This allows computer animation to be projected bY the light (10)
as a form of special effect, and even oPens the door to Projectins
onto the stage T.V. pictures that have been Processed bY the CPU
(512). Colour selection i9 achieved by the ~ame method as with the
other two embodiments of the coloured lisht source.
The intensitY of the three liquid crystal windows formins a
pixel, determines the colour that i9 perceived at that pixel.
Refering now to FIG. 2c, the third embodiment of the control
electronics will be discussed.
Control of the liquid crYstal Panel (103) is achieved bY the
control electronics (17). The control electronics (17) consists
mainly of two Parts, the image memorY (180) and the matrix control
electronics (181). The intensitY of each liquid crYstal window is
loaded into the corresponding memory location in the image memory
(180). This information is read bY the matrix control electronics
(181) which produces the control signals that vary the lisht
transmitting ProPerties of the liquid crystal windows. The imase that
appears on the liquid crYstal disPlay (103) is then projected by the
front lens sYstem (50). The control electronics (17) has the same
resolution of control as the two Previous embodiments of control
electronics (15,16) and can Produce the s~me range of colour
temperatures and colour. The white light source (74) requires no
control other than on and off. This removes the need to comPensate
for the varYing colour temperature of the light source if the
intensity of the source was variable. Further, there i9 no electrical
noise from the on/off control circuit since this control is Performed
during the zero crossing of the power lines feeding the light source
(74). Closed loop feedback through the monitoring circuit (501)
eliminates fluctuations in the intensitY of the light source (74) by
maintaining a constant level of Power to the light source (74).
Lastly, since the light source (74) does not require intensity
control, there i8 no need to use an incandescent light Rource and
other higher outPut light sources can be used in the light (10).
The special colour Qixins mirrors (201,202,203) used in the first
and second embodiments of the method of Producing a coloured light
beam in thia invention are not commercialY availible from the usual
sources of dichroic mirrors, and have to be custom manufactured for
this light (10). Also, the liquid crystal devices (91,92,93,103) used
in this invention need to be custom manufactured to produce the verY
high oPtical densities required to control the high outPut light
sources. All lens element~ (51,52,53,54,80,81,82,83,84) used in this
invention have anti-reflective coatings to reduce surface reflections
which increases the oPtical efficiency of this light (10).




. . ~ . ,.. .... ~ ... . .
~.~.':'' .

~b ' .

Representative Drawing