Note: Descriptions are shown in the official language in which they were submitted.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
1
DESCRIPTION
A METHOD OF MANUFACTURING FOIL FOR PRODUCING A PEPPER'S
GHOST ILLUSION
TECHNICAL FIELD
100011 The present invention relates to a foil for producing a Pepper's
Ghost
Illusion and in particular a transparent flame resistant foil for producing a
Pepper's Ghost Illusion. More specifically the invention concerns a method of
testing, rolling and storing, and transporting a transparent flame resistant
foil for
producing a Pepper's Ghost Illusion.
BACKGROUND ART
100021 Video production techniques are well known in the art and are
commonly used for creating lighting effects in motion pictures in the form of
Pepper's ghost images. Typically a real object or an image of a subject is
reflected
by a partially-reflective foil that also allows a background scene to show
through.
From the perspective of a viewer the foil is invisible and the reflected image
appears as a transparent "ghost" superimposed over the background scene.
100031 A conventional foil used in the production of a Pepper's ghost
illusion
is made from a polymeric or plastic film. A preferred polymer is polyester
which is
used for its superior mechanical properties which are enhanced by stretching
the
film as it is produced. Conventional plastic foil bums easily when exposed to
a
naked flame and melts at high temperatures. Consequently, a conventional foil
poses a safety risk and in the case of a fire the foil may melt and ignite and
cause a
rapid spread of flame and provide further fuel to the fire which will be
dangerous to
people in close proximity to the foil and may impede their safe evacuation.
100041 Accordingly, a conventional foil should not be used as part of a
lighting
rig or stageset on music and theatre performances, television shows,
nightclubs and
other public places where local, national or international fire and safety
regulations
require the use of fire retardant materials. Furthermore, the response of a
conventional foil to fire and heat may prevent a conventional foil being used
in
locations where the foil is likely to be in the proximity of heat-generating
lighting or
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
2
other such heat-generating equipment. This may prevent the erection of a
Pepper's
Ghost apparatus in confined spaces where close proximity of the foil to the
lighting
cannot be avoided.
100051 In an attempt to overcome this problem manufacturers have added a
fire resistant coating as an external layer on the outside of the transparent
foil
after the foil has been extruded or manufactured. However, the application of
the
external coating degrades the optical qualities of the transparent foil. In
particular,
the application of the external coating may result in a milky haze which makes
the
foil unsuitable for the Pepper's Ghost illusion. In order to be effective in
delivering
a quality image, the foil needs to be substantially transparent creating
little or no
dispersion of the light.
100061 There are also problems associated with the present storage and
transportation of the finished foil. Normally a foil is stored by placing a
glue strip
onto a roll core and sticking the end of the foil to the glued strip and then
rolling
the foil onto the core. However, the inventor has discovered that the glued
strip
causes a raised ridge in the foil that is carried through the rolls of the
foil. This
raised ridge results in deformities in the foil when it is unrolled making it
unsuitable for use in creating or producing a Pepper's Ghost illusion, as the
deformities/wrinkles will be evident to a viewer detracting from the illusion.
The
foil needs to be substantially wrinkle free and have very good optical and
mechanical properties.
100071 A number of associated problems are introduced due to the current
methods of storing and transporting the foil. As described above, when the end
of
the foil is glued to the core of the roll, the foil is then rolled onto the
core under
tension, in order to prevent adjacent foil surfaces from sticking together an
anti-
stick filler is added during manufacture which aids in preventing the adjacent
layers from sticking together. It has been found, in particular for foils
comprising a
flame retardant, that with a normal amount of anti-stick filler the haze of
the foil is
above acceptable levels of 5%. Such levels of haze once again making the foil
unusable for creating lighting effects and in particular for producing the
Pepper's
Ghost Illusion.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
3
100081 Accordingly, it is desirable to provide a foil for creating lighting
effects
and in particular for producing the Pepper's Ghost Illusion, that has the
required
physical and optical properties such as being fire resistant to comply with
local,
national or international fire and safety regulations and/or allow the foil to
be used
in the proximity of heat-generating lighting or other such heat-generating
equipment.
DISCLOSURE OF THE INVENTION
100091 According to a first aspect, the present invention provides a method
of
producing a Pepper's Ghost Illusion comprising using a reflective and
transparent
foil formed from a polymeric composite, the polymeric composite including a
flame
retardant.
100101 Passive fire protection is designed to protect elements of structure
in
the unfortunate event of a fire and also protect certain elements from
actually
catching on fire. Safety standards are laid down within the building
regulations to
which almost all buildings must adhere, these standards are there to ensure
the
protection of life, and not to protect the building. In order to meet these
strict
standards the present invention provides a flame resistant foil such that the
Pepper's Ghost illusion may be produced at a location where local, national or
international fire and safety regulations need to be met, or where they are
likely to
be used in the proximity to heat-generating lighting or other such heat-
generating
equipment. The flame resistant foil also should have the required optical
properties
required to produce the Pepper's Ghost illusion.
100111 Preferably, the foil may have a haze of less than 10%, and
optionally
or preferably less than 5% and further optionally or further preferably less
than
2%. The foil may be at least certified flame resistant to a European Class B
rating
under BS EN 13823 and BSEN 11925-2. The foil may be manufactured using a
continuous extrusion process. The flame retardant may be added to the
polymeric
composite prior to the polymerisation process. The flame retardant may
comprise
an organic phosphorous compound monomer that is polymerised in the
polymerization process. It will be understood that other suitable flame
retardants
may be used. For example, halogenated flame retardants, such as those
comprising
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
4
brominated or chlorinated compounds. However, the applicant believes
integration
of phosphorous based flame retardants into the compound of the foil is easier
than
halogenated flame detardants. Other suitable flame retardants could be used,
as
long as the flame retardant can be substantially, and preferably fully
dissolved, in
the polymeric composite in order to make an optical clear foil suitable for
use in a
Pepper's Ghost illusion. The foil may be produced on a biaxially-oriented
polyethylene terephthalate (BOPET) line.
100121 According to a further aspect, the present invention provides a
reflective and transparent foil formed from a polymeric composite comprising
an
organic phosphorous compound flame retardant and without an ultraviolet
stabiliser and/or any white pigment.
100131 The foil may be manufactured using an extrusion process and unlike
conventional glass screens the foil of the current invention is less likely to
shatter
and poses less danger to crew installing it or working along side the foil.
Unlike
glass screens the foil may be installed into moving scenery without fear of it
breaking as it is moved. This means that it is a very straightforward process
to fly
the system in and out of stages as required. The foil may be certified flame
retardant to a Class B under European fire testing standards.
100141 Preferably, the foil may be at least certified flame resistant to a
European Class B rating under BS EN 13823 and BSEN 11925-2. The foil may be
manufactured using an extrusion process. A flame retardant may be added to the
polymeric composite prior to the polymerization process. The flame retardant
may
comprise a monomer and preferably an organic phosphorous compound monomer
that is polymerised in the polymerisation process. The flame retardant may
result
in a flame resistant foil having a haze of less than 10%, and optionally or
preferably
less than 5%, and further optionally or further preferably less than 2%. The
foil
may be produced from a thin membrane comprising a flame retardant polyester
film. The foil may comprise a polyester flame resistant foil produced on a
biaxially-
oriented polyethylene terephthalate (BOPET) line.
100151 According to a further aspect, the present invention provides a
method
of manufacturing a partially reflective transparent foil for producing a
Pepper's
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
Ghost Illusion, the method comprising: adding a flame retardant to a monomer
mixture prior to polymerization causing polymerization of the monomer mixture
including the flame retardant to result in a polymeric composition; and
manufacturing the foil from the polymeric composition using an extrusion
process.
100161 By adding a flame retardant to the monomer mixture prior to the
polymerization process produces a resulting foil that meets the optical
requirements which allow the foil to be used in creating a Pepper's Ghost
Illusion.
For the foil to be used in creating this lighting effect the haze rating of
the foil is
preferably below 2% haze.
100171 Preferably, the manufacturing process may further comprise
stretching the foil to enhance the foils mechanical properties. The flame
retardant
may comprise an organic phosphorous compound containing monomer. The
extrusion process may further comprise a biaxially-oriented polyethylene
terephthalate (BOPET) line. Stretching the foil may comprise stretching the
foil in
both a longitudinal direction and in a transverse direction.
100181 According to a still further aspect, the present invention provides
a
method of manufacturing a partially reflective transparent foil for use in
creating
lighting effects, the method comprising: adding an additive to a monomer
mixture
after the polymerization process causing a polymerized monomer mixture and the
additive to result in a polymeric composition; manufacturing the foil from the
polymeric composition using an extrusion process; and wherein the additive in
the
resultant foil is capable of being activated by an external source to create a
lighting
effect.
100191 By placing an additive into the monomer after polymerization, and
then allowing the additive to be activated by an external source to produce a
lighting effect, substantially reduces the requirements for extra lighting
equipment
and still provides excellent optical and mechanical characteristics of the
foil. This
aspect of the invention provides a foil which may be used for more than just
producing a real object or an image of a subject when reflected by a partially-
reflective foil that also allows a background scene to show through. It allows
for
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
6
different backgrounds to be activated by using the additive or at least
provide
variations in the background being used.
100201 Preferably, the additive may comprise any one of nano-particles,
light
sensitive materials, pigments or dyes. The external source may comprise any
one of
ultraviolet light, any type of light source, electricity, chemicals or
temperature. The
additive may further comprise a light sensitive dye which when activated by
the
external source produces a lighting effect on an edge of the foil which
resembles a
trade mark or watermark.
100211 According to a still further aspect, the present invention provides
a
reflective and transparent foil for use in creating lighting effects, wherein
the foil is
formed from a polymeric composite comprising an additive, wherein the additive
in
the polymeric composite is capable of being activated by an external source to
create a lighting effect.
100221 Preferably, the foil may be for use in creating a Pepper's Ghost
illusion. The foil may be manufactured using a continuous extrusion process.
The
foil may be produced on a biaxially-oriented polyethylene terephthalate
(BOPET)
line.
100231 According to a still further aspect, the present invention provides
a
method of processing a reflective and transparent foil, the processing
comprising
gluing the foil to a core around which the foil will be rolled, wherein the
foil is
attached to the core by spraying glue onto a surface of the core.
100241 In order to produce a foil which may be used in a Pepper's Ghost
Illusion the foil must be substantially wrinkle free. By spraying the glue
onto the
core to secure the end of the foil there is less chance that the glue produces
a ridge
or raised portion that may result in wrinkles or other deformities being
formed in
the roll of foil. Accordingly, in one embodiment, the glue is sprayed onto a
surface of
the core such that the glue does not produce a significant ridge in the foil.
A
significant ridge is formed when there is no uniform distribution of the glue
on the
core and a ridge is formed in the roll of foil which reduces the amount of
foil on the
roll which can be used to produce a lighting effect. A significant ridge may
be a
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
7
ridge that is formed in a foil that is more than 50% of the thickness of the
foil. A
typical foil thickness varying from 24 to 120 microns.
100251 According to a still further aspect, the present invention provides
a
method of processing a reflective and transparent foil, the processing
comprising
gluing the foil to a core around which the foil will be rolled, wherein the
foil is
attached to the core by placing glue onto substantially all of the surface of
the core
such that the glue does not produce a significant ridge in the rolled up foil.
100261 Preferably, the glue may be placed on the surface of a roll to form
a
uniform layer of glue covering substantially all of the surface of a uniform
diameter
core.
100271 By placing glue onto the entire core further reduces the chance of a
significant ridge being formed and therefore improves the mechanical and
optical
properties of the foil by producing a low haze and substantially wrinkle free
foil.
100281 According to a still further aspect, the present invention provides
a
method of processing a foil for a Pepper's Ghost illusion, the processing
comprising
manufacturing a reflective and transparent foil and winding the foil onto a
core,
wherein the length of the foil rolled onto the core is a predetermined length
based
on the amount of anti-stick filler in the foil.
100291 In another embodiment the length of foil on the roll is also
dependent
upon the diameter of the core and the thickness of the foil. Preferably the
foil
length on a roll is between 10 to 40m, the core diameter is between 120mm to
350mm and the thickness of the foil is between 24 to 120 microns.
100301 By reducing the amount of foil which is rolled onto a core produces
a
lighter more easily handled roll of foil.
100311 According to a still further aspect, the present invention provides
a
method of processing a foil, the processing comprising manufacturing a
reflective
and transparent foil, and winding the foil onto a roll under a tension,
wherein the
amount of tension on the foil is limited to producing an internal stress in
the foil
which is in the range of 10% to 40% and preferably or optionally less than 15%
of
the foil's ultimate yield stress.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
8
100321 By reducing the amount of tension in the rolled up foil aids in
producing a foil which is free of deformities and has a good optical
characteristic.
100331 According to a still further aspect, the present invention provides
a
method of manufacturing a reflective and transparent foil, the manufacturing
comprising adding an antistick filler as part of the foil extrusion process
and
optionally or preferably adding an anti-stick filler to the polymeric
composite prior
to the polymerisation process, wherein the anti-stick filler prevents adjacent
foil
surfaces from sticking to one another.
100341 In order to prevent the rolled up foil from sticking to adjacent
surfaces
an antistick filler is used which prevents adjacent surfaces sticking
together. It is
also found that a reduced amount of filler has to be used when a fire
retardant
additive is used as using the normal amount of filler increases the haze
percentage
to an unacceptable level for a foil when used in creating a Pepper's Ghost
Illusion.
100351 By reducing the amount of anti-stick filler in order to obtain an
acceptable amount of haze, it is also possible to reduce the amount of foil
which is
rolled onto a roll. This makes the roll easier to move and also easier to
manipulate
the foil on the roll. Subsequently by reducing the amount of foil on a roll
also allows
the amount of tension applied to the foil to be reduced when it is wound or
unwound from the roll.
100361 A further subsequent advantage of reducing the amount of foil and
the
tension on the roll of foil also allows the spraying of the glue onto the core
to secure
the end of the foil. By spraying there is less chance that the glue will
produce a
ridge or raised portion that may result in wrinkles or other deformities being
formed in the roll of foil.
100371 Preferably, the anti-stick filler may be calcium carbonate. The foil
may
be a flame retardant foil and the amount of filler is reduced in order to
produce a
foil with a haze percentage of less than 10%, and preferably or optionally
less than
5%, and further preferably or further optionally less than 2%.
100381 According to a still further aspect, the present invention provides
a
method of performing quality control testing of a reflective and transparent
foil, the
method comprising: unrolling a section of the foil from a core onto another
core and
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
9
placing the unrolled foil under tension; and transmitting a pattern through
the foil
and determining whether the foil reflects the pattern without significant
distortion
in order to test the optical quality of the foil.
100391 By transmitting a pattern through a section of the foil and
analysing
the resultant pattern formed on the projected surface is used to identify
surface
defects and is a comparative test. It does not measure the back ground haze
level
but will show up optical contrasts. Thus it will identify wrinkles, marks
coming
from the extrusion dies or the rollers in the wind on machinery and rapid
changes
in transparency. It is a good quality control test which can distinguish the
good
from the bad but not the ultimate haze level.
100401 Preferably, the pattern may comprise a number of rectangular
coloured bars. In order to determine the optical quality of the foil the
transmitted
pattern may be checked to see that the pattern is not deformed.
100411 According to a still further aspect, the present invention provides
a
roll of foil for producing a Pepper's Ghost Illusion comprising a reflective
and
transparent foil formed from a polymeric composite, the polymeric composite
including a flame retardant.
100421 According to a still further aspect, the present invention provides
a
roll of a reflective and transparent foil formed from a polymeric composite
comprising an organic phosphorous compound flame retardant and without an
ultraviolet stabiliser and/or any white pigment.
100431 According to a still further aspect, the present invention provides
a
roll of a reflective and transparent foil for producing a Pepper's Ghost
Illusion
comprising, a flame retardant added to a monomer mixture prior to
polymerization
causing polymerization of the monomer mixture including the flame retardant to
result in a polymeric composition and wherein the foil is manufactured from
the
polymeric composition using an extrusion process.
100441 According to a still further aspect, the present invention provides
a
roll of a reflective and transparent foil for use in creating lighting
effects, wherein
the foil is formed from a polymeric composite comprising an additive, wherein
the
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
additive in the polymeric composite is capable of being activated by an
external
source to create a lighting effect.
100451 According to a still further aspect, the present invention provides
a
roll of foil comprising, a reflective and transparent foil rolled around a
core,
wherein the foil is attached to the core by spraying glue onto a surface of
the core.
100461 According to a still further aspect, the present invention provides
a
roll of foil, the roll comprising a reflective and transparent foil glued to a
core
around which the foil will be rolled around, wherein the foil is attached to
the core
by placing glue onto substantially all of the surface of the core such that
the glue
does not produce a significant ridge in the rolled up foil.
100471 According to a still further aspect, the present invention provides
a
method of processing a foil for a Pepper's Ghost illusion, the processing
comprising
manufacturing a reflective and transparent foil and winding the foil onto a
core,
wherein the length of the foil rolled onto the core is a predetermined length
based
on the amount of anti-stick filler in the foil.
100481 In another embodiment the length of foil on the roll is also
dependent
upon the diameter of the core and the thickness of the foil. Preferably the
foil
length on a roll is between 10 to 40m, the core diameter is between 120mm to
350mm and the thickness of the foil is between 24 to 120 microns.
100491 According to a still further aspect, the present invention provides
a
roll of foil comprising a reflective and transparent foil, wherein a tension
is applied
to the foil on the roll, wherein the amount of tension applied to the roll of
foil is
limited to producing an internal stress in the foil which is in the range of
10% to
40% and preferably or optionally less than 15% of the foil' s ultimate yield
stress.
100501 According to a still further aspect, the present invention provides
a
roll of foil comprising a reflective and transparent foil, the foil comprising
an anti-
stick filler added during the foil extrusion process and optionally or
preferably an
anti-stick filler added to the polymeric composite prior to the polymerisation
process, wherein the anti-stick filler prevents adjacent foil surfaces from
sticking to
one another.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
11
100511 According to a still further aspect, the present invention provides
a
roll of a reflective and transparent foil comprising performing a quality
control test
to determine an optical quality of the roll of foil, the quality control test
comprising:
a section of the foil unwound from a core under tension; and a pattern
transmitted
through the foil to determine whether the foil reflects the pattern without
significant distortion.
100521 A roll of foil is produced which may be used where local, national
or
international fire and safety regulations require the use of fire retardant
materials,
or where they are likely to be used in the proximity to heat-generating
lighting or
other such heat-generating equipment. By removing the UV stabiliser and/or the
white pigment produces a roll of foil that meets the requirements for
producing a
Pepper's Ghost Illusion.
100531 The various features of novelty which characterize the present
invention are pointed out with particularity in the claims annexed to and
forming
part of this disclosure. For a better understanding of the present invention,
its
operation, advantages and specific objects attained by its use, reference
should be
had to the accompanying drawings and descriptive matter in which preferred
embodiments of the invention are illustrated and described.
BRIEF DESCRIPTION OF THE DRAWINGS
100541 Figure 1 is a schematic of a foil according to an embodiment of the
present invention used when the foil is suspended from a roof;
100551 Figure 2 is a schematic of the method of manufacturing a flame
resistant foil according to an embodiment of the present invention;
100561 Figure 3 is a schematic of a Pepper's Ghost illusion according to an
embodiment of the present invention; and
100571 Figure 4 is a drawing showing two sets of lines of equal thickness
and
equal spacing.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
12
100581 BEST MODE FOR CARRYING OUT THE INVENTION
100591 To be effective in delivering a quality image, the image to be
projected
into the foil panel 10 and reflected should be projected as high definition
(HD) video
and if the projected image is to be a human figure, then the mirror or foil 10
should
be capable of producing a life size image. One of the requirements of a foil
panel 10
which is required in order to reproduce a quality image for a Pepper's Ghost
illusion
is the clarity of the foil 10. In order to produce a good quality illusion the
foil 10
should have less than 10% haze, and preferably less than 5% haze and still
further
preferably less than 2% haze. This means that any foil 10 which has more than
I
0% haze is not suitable for reproducing the Pepper's Ghost illusion. For
example,
any screen or foil 10 which, when manufactured exhibits a blurred image or a
somewhat milky haze of greater than 10% haze makes the foil unsuitable for the
Pepper's Ghost illusion. In order to be effective in delivering a quality
image, the
image to be projected into the foil 10 panel and reflected should be projected
as high
definition (HD) video.
100601 As described above haze is the scattering of light by a film that
results
in a cloudy appearance or poorer clarity of objects when viewed through the
film.
More technically, haze is the percentage of light transmitted through a film
that is
deflected more than 2.5 (degrees) from the direction of the incoming beam.
100611 The percentage haze is measured using a specimen of foil 10 (under
tension) which is placed in the path of a light beam. Light that passes
through the
foil 10 enters an integrating sphere, in which a photo detector measures the
total
light transmitted by the foil 10 and the amount of transmitted light that is
scattered by more than 2.5 . Haze is the percentage of total transmitted light
that
is scattered by more than 2.5 and is calculated by the following equation:
[MX
ft*
100621 Where
100631 a. Td = Scattered transmitted light
100641 b. Ti =Total transmitted light (To+ Td)
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
13
100651 c. To, = Transmitted light that does not deviate> 2.5
100661 In its most basic form, the reflective and transparent foil 10 is
formed
from a polymeric composite comprising a flame retardant which produces a foil
10
that is suitable for use in creating lighting effects and also the foil 10
does not
contain any UV stabilisers or any white pigment. The UV stabilisers and the
white
pigment are removed to aid in the production of a foil 10 which is capable of
producing a lighting effect and in particular, a Pepper's Ghost Illusion. For
example, a foil 10 which contains either or both of the UV stabiliser and the
white
pigment would not be able to be used to reproduce the Pepper's Ghost Illusion.
The
foil 10 is a flame resistant film produced with a phosphorous flame retardant
which
is polymerised in the polyester chain in the polymerization process. The flame
retardant is non-halogenated and nonmigrating. The flame resistant polyester
is
then processed into a polyester foil on a biaxiallyoriented polyethylene
terephthalate (BOPET) line where the properties of the material are enhanced.
The
process will be further described below.
100671 A polymeric composite is taken to mean any of the combinations or
compositions that comprise two or more materials, at least one of which is a
polymer. By combining a polymer with another material, such as glass, carbon,
or
another polymer, it is often possible to obtain unique combinations or levels
of
properties. Typical examples of synthetic polymeric composites include glass-,
carbon-, or polymer-fiber-reinforced thermoplastic or thermosetting resins,
carbon-
reinforced rubber, polymer blends, silica-reinforced or mica-reinforced
resins.
100681 The addition of the flame retardant allows the flame resistant foil
10
to be used as part of a lighting rig or stageset on music and theatre
performances,
television shows, nightclubs and other public places where local, national or
international fire and safety regulations require the use of fire retardant
materials.
Also such a flame resistant foil 10 can be used where they are likely to be in
the
proximity to heat-generated lighting or other such heat-generating equipment.
100691 The transparent-reflective foil 10 of the present invention is
essentially the same as a beam splitter. Those in the optical coating art will
understand the vast variations possible for the transparent-reflective foil 10
in
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
14
regard to its substrate, coating, and manufactured process. Plastic and glass
substrate foils 10, as well as stretched polyester, have been successfully
used for
the transparent-reflective foil 10. The transparent reflective foil 10 can
range from
a custom blend of optical coatings on a transparent substrate for superior
reflectivity and transmissivity all the way down to off-the-shelf one-way
mirrors
with inconsistent and poor optical qualities. Also, the reflectivity and
transmissivity, as well as other optical qualities of the transparent-
reflective flame
retardant foil 10, can be adjusted as required.
100701 The transparent-reflective foil 10 should have sufficient
transparency
to allow a camera to capture a quality image from the opposite side and to
allow
projected light to pass through without substantial reflection. The quality
image is
required for the Pepper's ghost illusion. The Pepper's ghost is an illusionary
technique used in theatre and in some magic tricks. Using a plate glass or
film 10
and special lighting techniques, it can make objects seem to appear or
disappear, or
make one object seem to "morph" into another. The transparent-reflective foil
10
must also be substantially reflective so that a quality image is reflected
from the
front projection screen. Antireflective coatings can be applied as needed to
suppress
unwanted reflections from any of the optical surfaces involved. On the back
side of
the transparent-reflective foil 10, opposite the viewing side, an
antireflection
coating can serve to eliminate the ghosting effect apparent with many types of
transparent-reflective panels. Despite the vast variations possible for the
transparent-reflective foil 10, the property of being both reflective and
transparent
remains the single most important constant.
100711 One known example for manufacturing a transparent-reflective foil 10
is to pressurise or depressurise a thin plastic membrane into a required
shape. By
using a multi-layer panel having a curved reflecting or transmitting facing
layer,
which may be produced by blowing a thin plastic membrane held in a frame and
then backed by a polyurethane layer supported by fibre glass to retain the
shape of
the thin membrane while being either pressurised or depressurized by a
pressure
chamber. Obviously there are other methods which can be used to produce the
foil
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
10 without departing from the scope of the invention, the present method is
used to
provide an example of one such method.
100721 As described above the foil 10 is produced from a flame resistant
polyester film. Flammability is defined as how easily something will bum or
ignite,
causing fire or combustion. The degree of difficulty required to cause the
combustion of a substance is subject to quantification through fire testing.
Internationally, a variety of test protocols exist to quantify flammability.
The
ratings achieved are used in building codes, insurance requirements, fire
codes and
other regulations governing the use of building materials as well as the
storage and
handling of highly flammable substances inside and outside of structures and
in
surface and air transportation.
100731 Materials can be tested for the degree of flammability and
combustibility in accordance with the respective countries standards. This
includes
the corresponding British standard BS 476 for testing passive fire protection
systems, as well as some if its constituent materials. In the European
harmonization of standards to classify materials according to their fire
resistance
the following classifications have been agreed:
100741 Al (Non-combustible);
100751 A2 (Limited combustibility);
100761 B;
100771 C;
100781 D;
100791 E; or
100801 F (No fire resistance).
100811 To obtain a classification for a high rating in products used for
construction, two tests are required. To obtain Euro Class B the product must
meet
a single flame test according to BS EN 11925-2 and a single burning item test
according to BS EN 13823 for the product to be used in public spaces.
100821 Preferably the flame retardant foil 10 according to the present
embodiment is certified flame retardant to Class B. The foil 10 can therefore
be
used in any area were a B rating is required. The foil 10 is also certified as
Euro
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
16
Class B rating under BS EN 13823 and BS EN 11925-2. The UL rating is VTM-2.
As the material is relatively thin it is classified under UL 94 for thin
materials (ie
materials that can be wound around a mandrel).
100831 As shown in Figure 1 a highly reflective and transparent foil 10 may
be rigged or suspended in panels or sheets or pieces or fragments with or
without
the use of a frame or tensioning devices (not shown). At its most simple, a
single
sheet of foil 10 may be hung or suspended freely or in a frame in such a way
as to
be in the path of one or more lights. Figure 1 shows a sheet of foil 10
suspended
from a roof, lit with a light source 2 along light path 3 such that the light
emitting
from the fixture hits the sheet of foil 10 creating an image 4. Part of the
light is
transmitted through the foil 10 onto another surface 5 along light path 6
creating a
further, enlarged image 8, and part of the light is reflected off the front of
the foil
along light path 7. The Applicants co pending application numbers WO
2005/096095 for a Projection Apparatus and Method for Pepper's Ghost Illusion
and
EP 0808325.5 for Projection Screen and Method of Construction are hereby
incorporated by reference. The respective applications provide details of the
frame
and tensioning devices used to produce a wrinkle free screen.
100841 Being able to see the shape of a light beam 2 as it passes through
the
plane of an almost invisible foil 10 creates the impression of a 2 dimensional
projection using a screen invisible to the viewing audience. This allows for
high
quality projection of light and images because the very thin nature of the
highly
reflective, transparent foil 10 with a reflective coating of high optical
quality will
not create double reflections within the image such as when glass is used, and
does
not allow for the path of the light beam to be seen through the air such as
when a
light beam passes through smoke.
100851 This characteristic is unique because it creates a high quality
image,
but does not readily identify the source of any light used to create an effect
on the
foil 10, so there is the possibility to obscure the source and mystify the
observers. It
furthermore removes the disadvantage experienced with traditional screens that
when the screen is not needed for viewing images, either it must be somehow
moved or removed (for example a roller screen may be deployed), or it requires
a
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
17
lighting effect or holding image to be placed upon it in order to avoid having
an
obvious blank surface visible to an audience.
100861 In one example, the foil 10 may be held at any angle between 0 and
90
degrees with respect to a mounting device which can be located on or near the
ceiling of a studio, or preferably at 45 degrees to the mounting device in a
frame
with tensioning devices employed to smooth out the surface of the foil 10. A
'Pepper's Ghost' effect or illusion may be created, allowing a reflection of
the light
beams to appear behind the foil 10. This is further described below and shown
in
figure 3.
100871 Further effects may be created by the light being projected from
different angles and being transmitted, reflected and refracted by the foil 10
or a
coating applied on one or both sides of the foil 10 or by an active element
held
within the foil 10. This may cause the creation of light beams of a colour
other than
the original source part of the beam due to a prismatic effect on the incident
light,
and the component wavelengths being separated out in the manner of white light
hitting a prism in such a way as a rainbow may be observed in the light coming
out
of the prism. This can also be created by distorting the foil 10 to cause the
light
beams to separate into beams of different colours.
100881 The fire retardant nature of the material allows for the placement
of
the foil 10 in areas in which non fire retardant articles would pose a risk,
and the
extreme lightness allows for rigging in positions which may not be available
had a
frame or truss been required to deploy the foil 10.
100891 Figure 2 shows a typical manufacturing process 100 of a polyester
foil
on a biaxially-oriented polyethylene terephthalate (BO PET) line 110. The
manufacturing process begins with a molten polyethylene terephthalate (PET)
120
being combined with a monomer 130 prior to the polymerization process 140. The
monomer 130 may be selected from one or more organic phosphorous compounds. It
is the phosphorous containing monomer 130 which gives the foil 10 the fire
retardant quality without degrading the optical characteristics of the foil
10. By
placing the monomer 130 in the polymerisation process 140 means that the foil
10
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
18
keeps the optical characteristics which are required when the foil 10 is used
in the
Pepper's Ghost illusion or for creating any type of lighting effect.
100901 The foil 10 is then extruded 150 onto a chill roll 160, which
quenches it
into a solid state. It is then biaxially oriented by drawing. The most common
way of
doing this is the sequential process, in which the foil 10 is first drawn in
the
machine direction 170 using heated rollers and subsequently drawn in the
transverse direction 180, i.e. orthogonally to the direction of travel, in a
heated
oven 190. It is also possible to draw the foil 10 in both directions
simultaneously,
although the equipment required for this is somewhat more elaborate. Draw
ratios
are typically around 3 to 4 in each direction.
100911 Once the drawing is completed, the foil 10 is "heat set" or
crystallized
under tension in the oven at temperatures typically above 200 C. The heat
setting
step prevents the foil 10 from shrinking back to its original unstretched
shape and
locks in the molecular orientation in the foil 10 plane. The orientation of
the
polymer chains is responsible for the high strength and stiffness of biaxially
oriented PET film, which has a typical Young's modulus of about 4 GPa. Another
important consequence of the molecular orientation is that it induces the
formation
of many crystal nuclei. The crystallites that grow rapidly reach the boundary
of the
neighboring crystallite and remain smaller than the wavelength of visible
light. As
a result, biaxially oriented PET foil 10 has excellent clarity, despite its
semicrystalline structure.
100921 If it were produced without any additives, the surface of the foil
10
would be so smooth that layers would adhere strongly to one another when the
foil
is wound or unwound, similar to the sticking of clean glass plates when
stacked.
To make handling possible, microscopic inert inorganic particles or an anti-
stick
filler are usually embedded or added to the PET to roughen the surface of the
foil
10. This makes the foil 10 ideal for use in providing the Pepper's ghost
illusion. The
foil 10 is wound up from the extrusion stretching ovens 190 onto steel master
cores
(not shown). These cores weigh between 2 to 3 tonnes and can be up to 10
meters
long.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
19
100931 The foil 10 on the master cores which require mechanical lifting
devices to handle is then unwound onto lighter transportation cores in foil
lengths
of between 10 to 40 meters. These cores are typically a uniform diameter roll
and
are made from cardboard, but could also be made from carbon fibre or glass
fibre
composites. The core with the foil 10 wound on, weigh between 40 to 100 kg and
with only 40 meters of foil 10 on the roll are easy to handle.
100941 It is also possible to include further additives after the
polymerization
process to produce a partially reflective transparent foil 10 capable of
creating a
lighting effect when activated by an external source. These additives can
include
nano-particles, light sensitive materials, pigments or dyes. For example,
another
possible additive is a light sensitive dye which when activated by the
external
source to produce a lighting effect on an edge of the foil 10, produces an
effect which
resembles a Trade Mark or watermark. This means the manufacturer has a simple
way of identifying his product by including the companies Trade mark in the
manufacturing process.
100951 A lighting effect can simply be the transmission or reflection of an
image as described above in relation to the Pepper's Ghost illusion. Also as
described above a lighting effect may be created by the light being projected
from
different angles and being transmitted, reflected and refracted by the foil 10
or a
coating applied on one or both sides of the foil 10 or by an active element or
additive
held within the foil 10. This may cause the creation of light beams of a
colour other
than the original source part of the beam due to a prismatic effect on the
incident
light.
100961 A different type of lighting effect may be created when the additive
in
the polymeric composite is a liquid crystal layer which when activated is
capable of
creating a lighting effect. For example, liquid crystals find wide use in
liquid crystal
displays, which rely on the optical properties of certain liquid crystalline
substances
in the presence or absence of an electric field. In a typical device, a liquid
crystal
layer (typically 10 1..tm thick) sits between two polarisers that are crossed
(oriented at 90 to one another). The liquid crystal alignment is chosen so
that its
relaxed phase is a twisted one (Twisted nematic field effect). This twisted
phase
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
reorients light that has passed through the first polarizer, allowing its
transmission
through the second polarizer (and reflected back to the observer if a
reflector is
provided). The device thus appears transparent. When an electric field is
applied to
the LC layer, the long molecular axes tend to align parallel to the electric
field thus
gradually untwisting in the centre of the liquid crystal layer. In this state,
the LC
molecules do not reorient light, so the light polarized at the first polarizer
is
absorbed at the second polarizer, and the device loses transparency with
increasing
voltage. In this way, the electric field can be used to make a pixel switch
between
transparent or opaque on command.
100971 Figure 3 shows the use of a foil 10 used to produce the Pepper's
ghost
illusion. In this example a studio 52 is located remotely from a stage or
theatre 60.
The studio 52 comprises a stage area or platform or a riser forming a stage
platform
on which the subjects 40 or performers are placed for greater visibility. For
example
a stage platform (riser) 47 approximately 1' high extends across the width of
the
studio 52 (generally 9' if arranged at one end of the trailer, or 20ft - 30
feet wide if
arranged lengthways across the trailer). Preferably steel deck stage or
similar
material gives the subject 40 a spatial boundary to work within and should
match
the dimensions of the show or theatre stage 60 or the camera 50 lens frame
area,
whichever is smaller. The camera 50 lens frame limits should be explained to
the
filmed subject 40 and markers set for him to see, though not visible to the
camera
50 lens. Although the height of the studio 52 need not be the same as the show
stage 60, the difference is an essential figure in calculating the height of
the camera
50. The stage platform also avoids having to set the camera 50 on the studio
floor to
achieve the correct height.
100981 The studio 52 is used to produce video and audio performances
wherein the studio 52 may allow a real time communication of a two-way
interaction between two or more subjects 40 located remotely of one another.
In
order for the Pepper's ghost illusion to work, the viewer or audience 38 must
be
able to see into the main room or theatre 60, but not into the hidden mirror
room or
studio 52. The edge of the foil 10 may be hidden by a cleverly designed
pattern in
the floor. In this case the two rooms are located remotely from one another.
The
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
21
studio 52 is located remotely from the theatre or stage 60. Both rooms may be
identical mirror-images; this approach is useful in making objects seem to
appear
or disappear, however it is not required that both rooms are identical if the
room or
studio 52 in which the subject 40 is completely black inside so as to not
include
anything other than the subject 40 in the captured image. This effect can also
be
used to make an actor reflected in the foil 10 appear to tum into an actor
behind the
foil 10 (or vice versa). This is the principle behind the Girl-to-Gorilla
trick found in
many haunted houses. The mirror room may instead be painted black (as in this
case with the studio 52), with only light-coloured objects in it. When light
from light
sources 51 is cast on the objects 40, they reflect strongly in the foil 10,
making them
appear as ghostly images 40 superimposed in the visible room or theatre 60.
100991 The lighting of the filming subject 40 may be of any type suitable
for
providing sufficient illumination for a high definition (HD) image capture. A
number of lighting assemblies 51 are located in the studio 52 suitable for
presenting an environment of immersive ambience to the audience 38 in a
viewing
venue or theatre 60 thus producing a compelling mixture of colour and contrast
on
stage and correctly illuminated live talent on stage and audiences for sharp,
realistic signal feeds and audience signal feeds.
1001001 In figure 3 a presenter or subject 40 resides behind an inclined,
reflective and transparent foil 10 onto which an image of, for example, a
motor
vehicle 42 is projected. The location of the subject or presenter 40 behind
the
projected image has a number of inherent advantages over systems where the
presenter 40 stands in front of a screen, not least of which is that the
presenter 40
does not obscure the projected image when walking across the projected image.
Additionally, the use of an inclined foil 10 results in a viewer or audience
38 of the
image perceiving the image as having depth rather than merely being a two
dimensional image, for example where a motor vehicle 42 is seen to rotate upon
a
turntable. The projection of an image upon a partially reflective foil 10 such
that is
observable by a viewer 38 positioned in front of the screen is known as the
"Peppers
ghost" illusion.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
22
1001011 In the manufacture of foils 10 it is possible to improve or change
foil 10
characteristics with additives or fillers added during the manufacture of the
foil 10.
The addition of additives and fillers can change the transparency and can be
used
to create different lighting effects. Another method of manufacturing a foil
10 to
create different lighting effects is to use multi-layer films. In general
multi-layer
films depend upon the number of extruders feeding a film line. Each extruder
provides one layer. For example, in a BO PET line 110 three extruders are
common,
however in figure 2 only one extruder 150 is shown but there can be more. The
advantage of a BO PET line 110 for foil production is the line width and the
enhanced mechanical properties of the foil 10.
1001021 [0 I 02] Each of the extruders 150 may or may not contain a
different
polymer formulation. Where the formulation is similar the different extruders
are
used to increase the productivity of the line. Most of the foil 10 production
is
application driven requiring different formulations for each layer. The
formulation
for the different layers often contain pigments or dies to change the colour
of the
foil 10 or may contain further additives or fillers to change the properties
of the
final foil 10 product. Multi-layer foil 10 with different colours and
different colour
densities can be easily produced to create different lighting effects in
addition to the
flame retardant properties .
1001031 Coatings applied during foil production or applied after production
can
also be used to change the colour or transparency of the foil and again may
assist in
creating different lighting effects. For example, PET foils 10 are often
metalized
under vacuum conditions in special purpose machinery to provide high gas
barrier
levels. The same vacuum metalizing process is also used to achieve special
optical
properties and a metallic look for decorative applications. Again this
technology
would apply to the development of foils I 0 for creating special lighting
effects.
Aluminium is the metal most commonly used but other metals can also be easily
applied.
1001041 There are also two further processes which can be used to produce
foil
for use in producing special lighting effects. These processes are Blown foil
and
Cast foil where often 5 or 6 extruders are used to build up a multi layer
film. In a
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
23
blown foil a plastic resin is heated and while it is still hot, an extruded
tube is
blown up like a balloon, with compressed air. This stretches the plastic and
makes
it thin. The balloon is made long enough to allow the plastic to cool. The end
of the
balloon is pinched together by rollers, to hold the air in and make the foil
flat. The
flat tube is then wound on to a steel master core. In a cast foil the polymer
is
squeezed between rollers, chilled and wound up as a thin plastic sheet or
film.
1001051 As described above the foil 10 is wound up from the extrusion
stretching oven 190 onto a steel master core. In order to prevent adjacent
layers
from sticking together an antistick filler is added to either the foil
extrusion process
or by adding anti-stick filler to the polymeric composite prior to the
polymerisation
process. Initially when a flame retardant was added to the foil 10 with the
normal
amounts of anti-stick filler the haze increased above the acceptable level of
2% thus
the anti stick filler amount had to be reduced for the production of a foil 10
for use
in creating lighting effects and in particular for producing the Pepper's
Ghost
Illusion.
1001061 Due to the reduced amounts of anti-stick filler required in order
to
achieve the percentage haze to less than 2% means that the length of foil 10
on
each master core has been reduced to between 400 to 800 meters. Due to the
size of
the roll of foil 10 on the master core mechanical lifting devices are required
in order
to handle and manipulate the steel cores. The foil 10 is then unwound from the
steel master core onto lighter storage/transportation cores in lengths of
between Sm
to 100m and preferably in the range of 10m to 40m.
1001071 These transportation cores are typically made from cardboard and
weigh between 40kg to 100 kg and with typically only 40 meters of foil 10
wound
onto the transportation core they are easy to handle. The transportation cores
could
also be made from carbon fibre or glass fibre composites. The transportation
cores
range in diameter from 120mm to 350mm. The diameter of the transportation core
and the wall sections of the core are related to minimise the deflection of
the cores
in the unwinding machinery and for transportation.
1001081 As described above, in order to store and/or transport the final
foil 10,
the foil 10 is rolled from the master core onto a transportation core under
tension.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
24
The tension on the foil is limited to producing an internal stress in the foil
which is
between 10% to 40% or preferably less than 15% of the foil's ultimate yield
stress.
The core may be cylindrical or any other shape which allows the foil 10 to be
safely
stored. For example a cardboard core with a smooth cylindrical surface may be
used. The storage onto the transportation cores introduces further problems.
1001091 When the foil 10 is attached to the transportation core the end of
the
foil 10 is glued to the core. Traditionally this glue is applied to the core
in a line
stretching across the core. This introduces a ridge into any foil 10 surface
which is
rolled onto the core. Due to the optical characteristics required for the foil
(preferably haze of< 2%) the ridge of glue across the core is not an option.
1001101 In order to overcome this problem a surface of the core is sprayed
with
glue or more preferably the whole of the cylindrical core has glue applied to
the
surface and the foil TO is wound onto the core under tension. Due to the
increase in
surface area of the glue applied to the core, means that a significant ridge
is not
formed in the foil 10. Typically a significant ridge is one that is more than
50% the
thickness of the foil 10, for a foil TO which has a thickness which will vary
from 24
to 120 microns. This ensures that any foil 10 rolled onto a core (other than
the
section which is glued) is substantially wrinkle free and the resultant foil
10 is able
to be used for producing the Pepper's Ghost Illusion. Accordingly, in one
embodiment, the glue is sprayed onto a surface of the core such that the glue
does
not produce a significant ridge in the foil. In a further embodiment the foil
10 is
glued to a core around which the foil 10 is rolled. The foil 10 is attached to
the core
by placing glue onto substantially all of the surface of the core such that
the glue
does not produce a significant ridge in the rolled up foil 10. Therefore, the
glue is
placed on the surface of a roll to form a uniform layer of glue covering
substantially
all of the surface of a uniform diameter transportation core.
1001111 The foil 10 is rolled onto a transportation core and the roll of
foil 10 is
then stored or is ready for transportation. The roll size is kept to a
reasonable size
to enable the roll to be easily moved and manipulated. For example, the amount
of
foil 10 rolled onto a roll is typically in the range of Sm to 100m and
preferably in the
range of 10m to 40m. Also, by reducing the size of the roll of foil 10 also
enables the
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
tension applied to the foil 10 to be reduced. The tension on the foil is
limited to
producing an internal stress in the foil which is between 10% to 40% or
preferably
less than 15% of the foil's ultimate yield stress.
1001121 The reduced tension in conjunction with the glue being sprayed to a
surface or the whole of the transportation core means that the first few
metres of
the foil 10 are not useable. By also reducing the size of the actual amount of
foil 10
rolled onto the cores also aids in reducing the effects mentioned above.
However,
the remaining foil 10 rolled onto the core does not have the ridge indented
into the
surface of the foil 10 and therefore meets the optical requirements for
producing a
foil 10 for use in creating lighting effects and in particular for producing a
foil 10 for
use in the Pepper's Ghost Illusion.
1001131 Another problem introduced by the rolling of the foil 10 onto cores
(ie
steel master core and the transportation core) is that adjacent foil surfaces
can
stick together when the foil 10 is wound or unwound from the core. In order to
prevent the foil 10 from sticking to the adjacent surfaces as it is wound or
unwound
from the cores, an anti stick filler is used. By adding anti-stick filler as
part of the
foil extrusion process or by adding anti-stick filler to the polymeric
composite prior
to the polymerisation process prevents adjacent foil surfaces from sticking to
one
another.
1001141 A typical filler used is calcium carbonate, however any known
filler
capable of being an anti-stick filler and still provide the required optical
and
mechanical properties may be used.
1001151 Also another problem which had to be overcome was when the flame
retardant was added to the foil 10 with the normal amounts of anti-stick
filler the
haze increased above the acceptable level of 2% thus the anti-stick filler
amount
had to be reduced for the production of a foil 10 for use in creating lighting
effects
and in particular for producing the Pepper's Ghost Illusion.
1001161 Therefore in order to produce a roll of foil 10 for a Pepper's
Ghost
illusion required the amount of anti-stick filler and the length of foil wound
onto
the core to be taken into consideration. When the foil 10 is wound onto a
core, the
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
26
length of the foil rolled onto the core is a predetermined length based on the
amount of anti-stick filler in the foil.
1001171 In order to test the optical characteristics, the foil lOis
unrolled under
tension. The mechanical tension ensures that the foil 10 is as flat and
wrinkle free
as possible. A light pattern is displayed using an amplified light source and
projected via a bounce screen or reflected from an LED wall. The amplified
light
source is used to show up any artifacts such as the 'moray' (rainbow of
colours) of
the projected image. Preferably the pattern is a number of coloured bars which
are
transmitted through the foil 10. The transmitted image is then checked for two
components of the coloured bar image. Firstly the transmitted image is checked
that a perfect rectangle is formed and secondly that the coloured bars line up
vertically and horizontally. This optical test is used to identify surface
defects and
is a comparative test. It does not measure the back ground haze level but will
show
up optical contrasts. Thus it will identify wrinkles, marks coming from the
extrusion dies or the rollers in the wind on machinery and rapid changes in
transparency. It is a good quality control test which can distinguish the good
from
the bad but not the ultimate haze level.
1001181 In order to determine and calculate the percentage of haze in a
test
piece of foil 10 the following available tests can be used. For example
percentage
haze can be measured by a method based on ASTM-D 1003-52. It is also possible
to
use a haze meter which is an instrument for measuring visibility or the
transmission of light through a medium. For example, the percentage haze is
measured using a specimen of foil 10 (under tension) which is placed in the
path of
a unidirectional light beam is directed onto the foil 10 specimen. After it
enters an
integrating sphere, a photo detector measures the total light transmitted by
the foil
and the amount of transmitted light that is scattered more than 2.5 . Haze is
the
percentage of total transmitted light that is scattered by more than 2.5 .
1001191 As described above the foil 10 is stored or transported on a
transportation core. To produce a foil 10 capable of being used for a Pepper's
Ghost
illusion the foil 10 must not be wrinkled or damaged while stored. The roll of
foil 10
consists of a roll of reflective and transparent foil 10. The foil 10 being
formed from
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
27
a polymeric composite comprising a monomer and preferably an organic
phosphorous compound flame retardant. The foil 10 preferably does not contain
an
ultraviolet stabiliser and/or any white pigment.
1001201 The foil 10 is wound up from the extrusion stretching ovens 190
onto
steel master cores. These cores weigh between 2 to 3 tonnes and can be up to
10
meters long. The foil 10 on the master cores which require mechanical lifting
devices to handle is then unwound onto lighter transportation cores in foil
lengths
of between 10 to 40 meters.
1001211 The foil 10 is attached to the transportation core by spraying glue
onto
a surface of the core. The glue must not produce a raised section in the
rolled up
foil. If there is a raised section this will be superimposed onto the rest of
the wound
up foil 10 and renders the foil unuseable for a Pepper's Ghost Illusion. In
order to
make the roll of foil easier to handle the amount of foil 10 wound onto the
roll is
reduced and subsequently the amount of tension applied to the foil 10 when
rolled
up onto the core is also reduced. This ensures that the foil 10 rolled onto
the roll
does not have any deformities or wrinkles or is substantially free of
deformities and
wrinkles.
1001221 In order to prevent the rolled up foil 10 from sticking to adjacent
foil
surfaces, an anti-stick filler is added as part of the foil extrusion process
or the
anti-stick filler is added to the polymeric composite prior to the
polymerisation
process. This prevents the foil 10 from sticking to the adjacent foil 10
surface and
prevents any deformities forming in the foil 10. Also, the amount anti-stick
filler
which is used is important, especially when the foil 10 includes a fire
retardant.
When the fire retardant was added to the foil 10 and the anti-stick filler was
added,
this raised the percentage haze in the roll of foil 10 to an unacceptable
level. In
order to produce the Pepper's Ghost Illusion a haze of< 2% is required. To
ensure
this figure is met the amount of anti-stick filler added to the foil 10 had to
be
reduced.
1001231 Finally the roll of foil 10 requires testing to ensure that the
roll of foil
10 meets the required optical qualities required for a foil for use in
producing the
Pepper's Ghost Illusion. The quality control testing of the roll of foil 10 is
carried
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
28
out by unrolling a section of foil 10 while under tension and transmitting a
pattern
through the foil in order to test the optical quality of the foil. The
transmitted
image determines the quality of the foil 10.
1001241 The Foil material is unrolled and held substantially flat and
smooth
under mechanical tension. The light amplifier may be a projector beaming light
onto a reflective "bounce screen" which the foil reflects as a peppers ghost
image.
An alternative light amplification source referred to an LED wall.
1001251 Part of the optical testing process referred to the assessment of
video
artefacts visible when projected through the foil known as the moray
(alternative
spelling moire) effect.
1001261 The Moire effect is a visual perception that occurs when viewing a
set
of lines or dots that is superimposed on another set of lines or dots, where
the sets
differ in relative size, angle, or spacing. The moire effect can be seen when
looking
through ordinary window screens at another screen or background. It can also
be
generated by a photographic or electronic reproduction, either deliberately or
accidentally.
1001271 Moire patterns are commonly seen on television screens when a
person
is wearing a shirt or jacket of a particular weave or pattern, such as a
houndstooth
jacket. This is due to interlaced scanning in televisions and non-film
cameras,
referred to as interline twitter. As the person moves about, the Moire pattern
is
quite noticeable. Because of this, newscasters and other professionals who
appear
on TV regularly are instructed to avoid clothing which could cause the effect.
1001281 The illustration in Figure 4 shows two sets of lines of equal
thickness
and equal spacing, but one set is angled at a few degrees while the other set
runs
vertically. The moire effect in this case appears as a set of thick, ill-
defined, nearly
horizontal bars.
1001291 Moire effect can produce interesting and beautiful geometric
patterns.
However, the phenomenon degrades the quality and resolution of graphic images.
1001301 The reproduction projected video images using the process of
peppers
ghost reflection via a semi-transparent screen relies on the optic to
faithfully
reproduce as accurately as possible a virtual image of the original projected
image.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
29
Ideally, the image being reflected should be as bright as possible in order
for that
reflection to be visible in environments as close as possible to natural light
levels.
The Moire effect is therefore an undesirable artefact which significantly
undermines the illusion of reality intended of a peppers ghost image.
1001311 The Moire effect is not overtly visible if the peppers ghost image
is
generated by an amplified light source which is either a projector or a flat
LCD/TFT
panel monitor. This is because the light pixels directed towards the semi-
transparent screen are effectively arranged upon a flat surface such as a rear
or
front projection screen or the panel "flat" panel monitor. Thus the reflection
is quite
uniform, particularly if the viewing audience perspective remains constant
(that is,
the audience is seated or otherwise does not move relative to the viewing
screen).
1001321 Even if projection or flat panels are used however, the Moire
effect
becomes more evident if the video image contains large areas of white because
the
incidence of white light being reflected through a semitransparent screen
creates a
series of mini prism effects, hence the association of the Moire effect with
the
rainbow of colours.
1001331 The technical development of LED panels in recent years has
challenged the image supremacy previously accorded to high brightness, high
definition projection, particularly for larger video images measuring 4m
(13ft) or
more in width and 2m (6ft 6") or more in height. It is well known that LED has
always been significantly brighter than even the brightest projectors of
40,000
lumens or more.
1001341 Thus LED panels have remained of interest to producers of peppers
ghost images wishing to achieve the maximum brightness for their displays in
order to broaden the environments in which the displays can be seen and
enjoyed.
Environments such as airports or shopping centers are traditionally areas of
high
ambient light which hitherto have posed greater challenges for peppers ghost
work
to be displayed effectively. However, the spacing between each small LED lamp -
known as the "pixel pitch" - has been found to be greater than the pixel pitch
effectively achievable from an HD projector, resulting in the image appearing
pixelated to viewers (that is the individual pixels comprising to form the
overall
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
image are visible). A pixelated image is unacceptable for most peppers ghost
displays as it renders the virtual image somewhat less than virtual,
fundamentally
undermining the desired illusion. Pixel pitch for an LED panel is typically
measured in mm. Thus a 6mm pixel pitch means that the lamps are 6mm apart. A
2.5mm pixel pitch means the lamps are approximately 2.Smm apart.
1001351 Taking this LED pixel measurement metric as a comparison against
projection, a typical HD projector of 1920 x 1200 for an image measuring 4m
wide
by 2.4m high means that the projected image 4,000mm wide should be divided by
1920 pixels - an effective pixel pitch therefore of approximately 2.1 mm.
1001361 Previous prior art concerning the optimal sizing for peppers ghost
images has concluded that for regular viewing distances of 6m or more (from
audience to the image) the pixilation effect can be overcome to produce an
acceptable virtual image of a human being by achieving a projected pixel pitch
of
2.5mm or less. That is, using a 1920 x 1200 projector with a minimum
brightness of
8,000 lumens, the maximum projected image size should optimally be no greater
than Sm wide size in order for the viewing audience to perceive the virtual
image
as retaining its substantive form against the original. If the audience
viewing
distance is greater than 6m then the image size may be increased accordingly.
If
the audience viewing distance is less than 6m, then the image size should be
decreased accordingly.
1001371 A formula providing a rule of thumb for optimizing image resolution
relative to the audience viewing distance would be:
1001381 Pixel Pitch= P
1001391 Image Size (in width)= I
1001401 Audience Viewing Distance= D
1001411 I=DxP
1001421 The key technical development of LED panels over the past several
years has been in the reduction of available pixel pitch with a corresponding
reduction in cost of purchase. Today, 6mm, 4mm and 3mm pixel pitch is widely
in
use, 2.5mm pixel pitch is more commonplace and gaining commercial viability.
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
31
1.6mm pixel pitch is commercially available, albeit at a price point far
higher than
commercially viable for most audio video applications, including peppers
ghost.
1001431 Typically, LED offers 6-20 times the level of brightness offered by
projectors of 18,000 lumens. It is therefore desirable to create peppers ghost
productions suitable for display using LED panels as the amplified light image
source.
1001441 Peppers ghost displays using a semitransparent screen manufactured
from PET (polymers) are considered to be the de facto standard for displays
using
screens with surface areas in excess of 10m2.
1001451 However, the polymer screens contain various pigmented particles
such as antistick filler or flame retardant which render the screen less than
fully
transparent and which contribute to the Moire effect.
1001461 The use of LED panels with polymer screens further exacerbate the
Moire effect due to the orientation of their light beams being arranged in a
true 3D
plane, rather than the flat plane as previously described for projection and
flat
panels. This 3D orientation creates a scenario when used with polymer screens
whereby the reflected image suffers apparent degradation to the viewing
audience
caused by the incidence of the light beams being "interlaced" by the process
of
reflection, unless the viewer is situated perfectly perpendicular to the
reflected
image.
1001471 The purpose of this invention is to provide a solution to this
interlacing moire effect for peppers ghost installations comprising semi-
transparent
polymer screens of at least 3m in width whereby the amplified image source
uses
LED panels in respect of which the audience will view some or all of the
reflected
images off axis from the perpendicular.
1001481 According to the first aspect of this invention, a semi-transparent
polymer screen is arranged at an angle of approximately 45 degrees to an image
source comprising LED panels of 3mm pitch or greater. The angle could be 40
degrees or 50 degrees, or even parallel - that is the LED is facing the
polymer
screen at an angle largely parallel. The LED panels are then overlaid with a
thin
rear projection diffusion screen. The diffusion screen is typically black in
colour,
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
32
between lmm and 4mm thick. The screen may be a rigid panel or a sheet of film.
The distance between the rear section of the diffuser screen and the front
surface of
the LED tile can be Omm-10,000mm.
1001491 Rigid panels are limited in size - typically a maximum of 80" x
120".
Examples of usable diffusion panels are the Pro Display Ultra BlackTM Pro-
Diffusion HD and "Mirrorvision" Screens:
1001501 (http ://www.p rodisp lay. com/download/ultra-black-rear-p roj
ection-
screen.pdf)
1001511 http ://www.p rodisp lay. com/download/p ro-diffusion-rear-p roj
ection-
film.pdf
1001521 Either of the Ultra Black Pro Diffusion or Mirrorvision screens are
overlaid directly onto the image bearing LED panels (also known as tiles),
resulting
in a very bright, high contrast rear projection screen effect. The LED panels
are
typically arranged flat upon a surface facing directly upwards or pointing
directly
downwards.
1001531 By using these diffusion screens overlaid upon the LED tiles
directed
towards a transparent or semi-transparent polyester Foil screen arranged at
approximately 45 degrees to the LED, the Moire effect for images transmitted
through a semi reflective Foil is largely eliminated or diffused - even if the
polymer
Foil contains flame retardant or anti stick filler particles.
1001541 There are two key reasons how. The first occurs by way of unifying
the
surface plane upon which the pixels of the LED are transmitted relative to the
reflective Foil screen - the diffusion screen being a flat 2D surface is
arranged in
between the LED light path and the Foil. Thus the LED light pixels are
transmitted from a uniform flat 2D surface as opposed to the 3D terrain of an
uncovered LED panel transmitting to the Foil directly. Secondly, by way of
optical
light diffusion - that is the apparent brightness of an amplified light image
transmitted through such a diffuser surface to an observer is the same
regardless of
the observer's angle of view. This consistency of light output is transmitted
through
the transparent Foil in a similar manner, resulting in the reflected image -
or
CA 02969537 2017-06-01
WO 2016/089901 PCT/US2015/063240
33
peppers ghost - appearing consistent in brightness and contrast from different
(or
isotropic) angles of the audience view.
1001551 For larger peppers ghost image displays utilizing Flame Retardant
Foil apparatus requiring the diffusion of LED, or in circumstances where the
pixel
pitch of the image bearing LED is 3.5mm or less, another type of rear
projection
material may also be used and in certain high ambient light environments may
also
be more desirable to deploy as an alternative to Pro Display Screens. One
example
is the Stewart Filmscreen 100. These rear projection screens are flexible film
materials, typically pigmented grey in colour to optimize image contrast
transmitted from the LED. http://www.stewartfilmscreen.com/materials/rear-
projection/filmscreen-100
1001561 One key advantage over the Pro Display screens is that the
Filmscreen
100 material is available in sizes of up to 40 feet x 90 feet without any
visible
seams. The absence of seams is important to ensure the reflected peppers ghost
image appears as true to the original as possible, with minimal distortion.
1001571 Although the present invention has been illustrated and described
with respect to exemplary embodiment thereof, it should be understood by those
skilled in the art that the foregoing and various other changes, omission and
additions may be made therein and thereto, without departing from the scope of
the
invention. Therefore the present invention should not be understood as limited
to
the specific embodiment set out above but to include all possible embodiments
which can be embodied within a scope encompassed and equivalent thereof with
respect to the features set out in the appended claims.
