Note: Descriptions are shown in the official language in which they were submitted.
CA 02234643 l998-04-l4
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PROJECTOR
The present invention relates to projectors.
Various types of video and computer generated
information projectors are known. These include, for
example, the SharpVision product line commercially avail-
able from Sharp Corporation of Japan. Conventional
projectors of this type have achieved significant market
penetration but suffer from various disadvantages and
limitations.
One of the significant limitPtiorls in liquid
crystal panel projectors lies in the relatively limited
amount of light that can be projected. It may be appreci-
ated that the amount of light that can be transmitted
through a conventional color liquid crystal panel assem-
bly is limited by the amount of light that can be ab-
sorbed by the liquid crystal panel without degradation
of its performance and permanent damage thereto inter
alia mainly due to overheating. Accordingly the bright-
ness of projected images produced by such projectors is
correspondingly limited.
The present invention seeks to provide an
improved projector which is highly efficient in light
utilization.
There is thus provided in accordance with a
preferred embodiment of the present invention a projector
comprising:
a non-polarized light source;
a polarizing beam splitter receiving light from
the non-polarized light source; and
a selectably actuable polarization rotating
light valve having light polarized in one sense from the
polarizing beam-splitter impinging thereon from a first
direction and having light polarized in an opposite sense
from the polarizing beam-splitter impinging thereon from
a second direction.
In accordance with a preferred embodiment of
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the present invention, when the light valve is not actu-
ated, the light polarized in both the one sense and the
opposite sense passes therethrough without changes in
polarization.
Further in accordance with a preferred embodi-
ment of the present invention, when the light valve is
actuated, the light polarized in both the one sense and
the opposite sense passes therethrough with changes in
polarization to an extent determined by the actuation.
The range of rotat~on produced by th~ l~ght valve is from
Q to 9~ degrees.
Additionally in accordance with a preferred
embodiment of the invention, when the light valve is not
actuated all of the light is directed to an objective
lens.
Still further in accordance with a preferred
embodiment of the invention, when the light valve is
actuated to cause a 90 degree rotation of the polariza-
tion, all of the light is directed back to the light
source.
In this manner, very small light losses and
heat dissipation is encountered at the light valve,
enabling relatively high brightness to be achieved using
relatively low power light sources.
Preferably, the light valve is a liguid crystal
light valve from which polarization plates have been
removed. Preferably the light valve comprises a multi-
plicity of independently electrically actuable regions,
corresponding to pixels.
In accordance with a preferred embodiment of
the present invention, the polarizing beam splitter
comprises a pair of prisms which are cemented together
with multiple dielectric layers therebetween. In accord-
ance with another preferred embodiment of the present
invention, the beam splitter is a crystallizing polariz-
ing beam splitter. Other suitable types of ~olarizing
CA 02234643 1998-04-14
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beam splitters may also be employed.
-~The projector may be monochromati~ or may
operate in color. In order to enhance light utilization
efficiency when the projector operates in color, prefera-
bly, the selectably polarization rotating light valve
comprises:
a shutter assembly having a multiplicity of
pixel light valves; and
a color separator disposed on each side of the
shutter assembly, intermediate ~he light sourc~ and the
shutter assembly and spaced therefrom and providing a
plurality of spatially separated differently colored
light beams;
wherein the plurality of spatially separated
differently colored light beams are in predetermined
registration with the multiplicity of pixel light valves.
Alternatively a color projector may employ
three separate monochromatic light sources, polarizing
beam splitters and selectably actuable polarization
rotating light valves, whose outputs are combined into a
single image.
It will be appreciated that the present inven-
tion provides greatly enhanced light utilization effi-
ciency, which may reach one order of magnitude, as com-
pared with prior art devices.
The present invention will be understood and
appreciated more fully from the following detailed de-
scription, taken in conjunction with the drawings in
which:
Fig. 1 is a simplified schematic illustration
of a projector constructed and operative in accordance
with a preferred embodiment of the present invention;
Figs. 2 and 3 are simplified schematic illus-
trations of the passage of two differently polarized
components of one ray of light through part of a projec-
tor constructed and operative in accordance with a pre-
CA 02234643 l998-04-l4
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ferred embodiment of the present invention in respective
first and second operative states;
Fig. 4 is a simplified schematic illustration
of a color projector employing three monochromatic subas-
semblies in accordance with an alternative embodiment of
the present invention;
Fig. 5 is a simplified schematic illustration
of a color projector employing three monochromatic subas-
semblies in accordance with a further alternative embodi-
ment of t~e present invention;
Fig. 6 is a simplified schematic illustration
of a color projector employing three monochromatic subas-
semblies in accordance with yet another alternative
embodiment of the present invention;
Fig. 7 is a simplified schematic illustration
of a projector constructed and operative in ~ccordance
with another preferred embodiment of the present inven-
tion;
Fig. 8 is a simplified schematic illustration
of a projector constructed and operative in accordance
with yet another preferred embodiment of th~ present
invention;
Fig. 9 is a simplified schematic illustration
of a color projector constructed and operative in accord-
ance with still another preferred embodiment of the
present invention;
Fig. 1~ is an illustration of a projector
employing two light valve arrays in a reflective mode in
accordance with one embodiment of the present invention;
Fig. 11 is an illustration of a projector
employing two light valve arrays in accordance with
another embodiment of the present invention;
Fig. 12 is an illustration of a projector
employing two light valve arraYS in accordance with yet
another embodiment of the present invention, which pro-
vides enhanced contrast;
CA 02234643 l998-04-l4
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Fig. 13 is an illustration of a color projec-
tor employing two light valve arrays in accordance with
still another embodiment of the present invention, which
provides enhanced contrast;
Fig. 14 is an illustration of a color projec-
tor emploYing two light valve arrays in accordance with a
further embodiment of the present invention, which pro-
vides enhanced contrast;
Fig. 15 is an illustration of the operation of
~art of the apparatus of Fig. 14;
Fig. 16 is an illustration of a color projec-
tor employing two light valve arrays in accordance with a
still further embodiment of the present invention; and
Fig. 17 is an illustration of the operation of
part of the apparatus of Fig. 16.
Reference is now made to Fig. 1, which is a
simplified schematic illustration of a projector con-
structed and operative in accordance with a preferred
embodiment of the present invention. The projector of the
present invention comprises a light source 10, such as a
metal halide arc lamp manufactured by Osram or Philips
combined with a suitable reflector, which outputs a
generally collimated beam of light 11 to a ?olarizing
beam splitter 12. The polarizing beam splitter may be any
suitable polarizing beam splitter and may be similar to,
for example, a broadband polarizing cube beam splitter,
commercially available from Melles Griot or a crystal
polarizer beam splitter, commercially available from
Spindler & Hoyer.
According to a preferred embodiment of the
present invention, the polarizing beam splitter may be
based on a liquid crystal layer disposed betwean a pair
of prisms. Such a polarizing beam splitter which is
achromatic and has a large acceptance angle, is
commercially available from Philips Key Modules Group,
Building SWA 8, 56Q~ JB Eindhoven, the Netherlands.
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Although a prism-type beam splitter is illus-
trated throughout, it is appreciated that a planar type
beam splitter is equally applicable.
The operation of the apparatus of Fig. 1 may be
best appreciated by a consideration of a number of indi-
vidual differently polarized components of individual
rays of light forming beam 11 together with a considera-
tion of Figs. 2 and 3, which show the passage of the
differently polarized components of individual rays of
light separately through respsctive actuated and non-
actuated pixels of the light valve array.
A first polarized component of a ray of light,
represented by a solid line, and labeled ls, is reflected
by the polarizing beam splitter 12 via a mirror 14 to
impinge upon a light valve array 16 in a first direc-
tion, indicated by arrows 18. A second polariz~d compo-
nent of the same ray of light, polarized orthog~nally to
the first polarized component of light represented by a
dashed line and labeled lp, passes through beam splitter
12 and is reflected from a mirror 2~ to impinge upon
light valve array 16 in a second direction, indicated by
arrows 22.
The light valve array 16 may be any suitable
light valve array and is preferably a liquid crystal
light valve array from which the polarization plates
thereof have been removed. The liquid crystal light valve
array may be monochromatic but is preferably a color
array. A preferred embodiment of a color liquid crystal
light valve array is described and clAimed in
applicant/assignee's Published European Patent Applica-
tion ~631434.
If it is desired to employ commercially avail-
able off-the-shelf liquid crystal light valves which are
normally aligned at 45 degrees with respect to their
frames, it is necessary to rotate such liqui~ crystal
light valves in their respective planes about the optical
CA 02234643 1998-04-14
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axis of the system by 45 degrees, such that the resulting
polarization will coincide with either the s or the p
polarized beam components. It is appreciated tllat using
conventional technology liquid crystal light valves which
are aligned parallel to the rows or columns therein may
be used for the purposes of the present invention.
When commercially available off-the-shelf
liquid crystal light valves are employed, they ~re opera-
tive to transmit light in the absence of the application
of an electrical vQltage thereto. This is known as opera-
tion in a normally white mode, as distinguished from
operation in a normally black mode, when the light valves
are opaque in the absence of the application of an elec-
trical voltage thereto.
In the apparatus of the present invention,
liquid crystal light valves which are designed to operate
in the normally white mode would have the opposite effect
and block transmission of light. Accordingly, convention-
al off-the-shelf li~uid crystal light valves should be
operated in an electrically inverse mode or an additional
9~ degree polarization rotator should be employed.
Each pixel in the liquid crystal light valve
array may be independently electrically controlled to
selectably rotate the polarization of light passing
therethrough. The selectable polarization cause3 rotation
of light passing therethrough in a range of ~ to 9~
degrees. For the purpose of simplicity in ilLustration
and explanation, only two operative states of the light
valve array are here considered, namely ~ degrees rota-
tion and 9~ degrees rotation, it being understood that
grey scales may be expressed by intermediate anounts of
rotation.
Returning to a consideration of Fig. 1 and of
components ls and lp, it is seen that they bot~ impinge
on a pixel which is hatched to indicate 9~ degree rota-
tion. Thus the ls component is converted at the light
CA 02234643 l998-04-l4
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valve to a lp' component and the lp component is convert-
ed to a ls' component. The resulting lp' component is
reflected by mirror 2~ to pass through beam splitter 12
to the light source 10. The resulting ls' component is
reflected by mirror 14 and is reflected at beam splitter
12 to the light source 1~. Thus it is seen that both
differently polarized components of a beam which impinges
on an actuated pixel of the light valve array 16 are
eventually reflected back to the light source.
Turning to a consideration of a second light
ray having mutually orthogonally polarized components 2s
and 2p, it is seen that first polarized component 2s, is
reflected by the polarizing beam splitter 12 via mirror
14 to impinge upon light valve array 16 in the first
direction, indicated by arrows 18. The second polarized
component of the same ray of light, polarized orthogonal-
ly to the first polarized component of light represented
by a dashed line and labeled 2p, passes through beam
splitter 12 and is reflected from mirror 2~ to impinge
upon light valve array 16 in a second direction, indicat-
ed by arrows 22.
Both differently polarized components impinge
on a pixel which is blank to indicate ~ degree rotation.
Thus the 2s component is not converted at the light valve
and remains a 2s' component and the 2p component is also
not converted and remains a 2p' component. The 2p'
component is reflected by mirror 14 to pass through beam
splitter 12 to the objective lens 24. The 2s' component
is reflected by mirror 2~ and is reflected at beam split-
ter 12 to the objective lens 24. Thus it is seen that
both differently polarized components of a beam which
impinges on an non-actuated pixel of the light valve
array 16 are eventually directed to the objective lens.
It is noted that the light valve array 16 should be
placed optically equidistant from the objective lens
along the light paths of both the p and the s components,
CA 02234643 1998-04-14
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such that the objective lens 24 equally images both sides
of the light valve array.
It may be appreciated that in the arrangement
of the present invention. depending on the image defined
by the polarization states of the various pixels the
light is directed either through an objective lens 24 or
reflected back to the light source 10, where it may be
used to heat the plasma therein, or alternatively be
redirected through the projector. Accordingly the heat
accumulation at the light valve array due to ligh~ ab-
sorption thereat is minimized.
It is a particular feature of the present
invention that light of different polarization impinges
on the light valve array 16 simultaneously in opposite
directions. It is also a particular feature of the
present invention that the light impinges upon through
the beam splitter twice in every case. These features
enable light of both polarizations to contribute to the
brightness of an illuminated pixel.
The embodiments described hereinabove may be
either monochromatic or color depending on whether color
filtration is provided.
Reference is now made to Fig. 4, which illus-
trates an embodiment of a color projector. Here three
generally identical monochromatic color subassemblies,
labeled respectively 4~, 42 and 44 and each including a
polarizing beam splitter 12 and a monochromatic light
valve array 16, receive light via dichroic beam splitters
46 from a polychromatic light source 48 which may be
identical with light source 1~ described hereinabove.
Each of the subassemblies may be constructed
and operative as described hereinabove with reference to
Figs. 1 - 3. The outputs of light downstream of the light
valve arrays 16 pass through the respective beam split-
ters 12 of each subassembly and are reflected by mirrors
5~ so as to direct the light via dichroic beam combiners
CA 02234643 l998-04-l4
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1 (~)
52, and through a single objective lens 54.
Reference is now made to Fig. 5, whi-h illus-
trates a further alternative embodiment of a color
projector. Here light from a light source 6~ passes
through a polarizing beam splitter 62. The resulting two
mutually orthogonally polarized components of the light
are directed to respective dichroic beam splitt~-rs 64 and
65.
The red, green and blue components are directed
by respecti~7e mirror p~irs 66, 68; 7(), 72 and 74. 76
through three respective monochromatic light valve arrays
78, 8(~ and 82. Light which has passed through one of the
three light valve arrays 78, 8~) and 82 is reco:nbined at
beam splitter 62 and directed via an objective lens 84 to
provide an image output.
Each of the subassemblies may be constructed
and operative as described hereinabove with reference to
Figs. 1 - 3.
Reference is now made to Fig. 6, which illus-
trates a color projector employing three monochromatic
subassemblies in accordance with yet another alternative
embodiment of the present invention. Here a light source
9~ emits a light beam which impinges on a dichroic beam
splitter 92. Blue light reflected therefrom impinges on a
polarizing beam splitter 94. The resulting two mutually
orthogonally polarized components of the blue light are
directed by respective mirrors 96 and 98 via a light
valve array 99 and via polarizing beam splitter 94 which
directs them to a dichroic beam combiner 1~. Beam
combiner l~Q directs the blue light through an objective
lens 11~)2.
The red and green components are transmitted
through dichroic beam splitter 92 and impinge on a fur-
ther dichroic beam splitter lQ4. The green component is
transmitted therethrough and impinges on a polarizing
beam splitter 1()6. The resulting two mutually orthogonal-
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ly polarized components of the green light are directed
by respective mirrors 1~8 and llQ via a light valve array
111 and via polarizing beam splitter lQ6 which directs
them to dichroic beam combiner 1~0, which transmit the
green light through objective lens lQ2.
The red component is reflected by the dichroic
beam splitter 1~4 onto a mirror 114 which directs it to a
mirror 116, which reflects it onto a polarizing beam
splitter 118. The resulting two mutually orthogonally
polarized components of the red light are directed by
respective mirrors 12~ and 122 via a light valve array
123 and via polarizing beam splitter 118 which directs
them to dichroic beam combiner 1~, which directs the
red light through objective lens 1~2.
Reference is now made to Fig. 7, which illus-
trates a projector constructed and operative in accord-
ance with another preferred embodiment of the present
invention. The projector of Fig. 7 may be identical to
that of Fig. 1, with the additional feature that one or
both of mirrors 214 and 22~ may be adjustably position-
able, dynamically or statically by alignment apparatus
221 and 215 respectively. The remaining elements of the
structure are indicated by identical reference numerals.
By using the adjustably positionable nirror or
mirrors 214 and 220 one may cause two slightly mutually
translated images of a pattern on the light valve array
16 to be projected via objective lens 24. This may pro-
duce depixelization of the resulting image, which is
desirable in certain applications, such as video dis-
plays.
Fig. 8 illustrates the apparatus of Fig. 7
with the addition of apparatus for dynamically varying
the position of mirrors 214 and 22~. This apparatus may
include, for example, piezoelectric assemblies 222 and
224, as illustrated in Fig. 8. By using the appPratus of
Fig. 8, one may produce interlaced image fields and thus
CA 02234643 l998-04-l4
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achieve enhanced image resolution, which may double or
triple the number of rows per image without adding addi-
tional resolution requirements to the remainder of the
apparatus, provided that the frame rate of the light
valve array 16 is sufficiently high.
Reference is now made to Fig. 9, which illus-
trates a color projector constructed and operative in
accordance with a preferred embodiment of the present
invention. A light source 25t~) projects a beam of light
via a color wheel 252 or any o~her suitable device for
sequentially transmitting the R, G and B spectral compo-
nents of the beam, onto a polarizing beam splitter 254.
The resulting two mutually orthogonally polarizod compo-
nents of the R, G and B spectral components are directed
by respective mirrors 256 and 258 via a light valve array
26() and via polarizing beam splitter 254 which directs
them through an objective lens 262.
Reference is now made to Fig. 10, which illus-
trates a projector employing two light valve arrays in a
reflective mode. Light from a light source 27(~) impinges
on a polarizing beam splitter 272. The resulting two
mutually orthogonally polarized components of the light
are directed via two separate light valve arrays 274 and
276 and respective ~uarter wave plates 278 and 28(~ to
respective mirrors 282 and 284. The light is reflected
back via respective guarter wave plates 278 and 28() and
light valve arrays 274 and 276 to polarizing beam split-
ter 272 and is directed thereby through an objective lens
286.
The light valve arrays 274 and 276 both operate
in a reflective mode. It is noted that the light valve
arrays 274 and 276 do not include polarizers.
As in the embodiments of Figs. 7 and 8, by
slightly translating either of the light valve arrays 274
and 276 along respective arrows 2gt) and 292 or perpen-
dicularly thereto in the same plane one may cause two
CA 02234643 l998-04-l4
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slightly mutually translated superimposed images of
patterns on the light valve arrays to be projected via
objective lens 286. When identical images appear on both
light valve arrays 274 and 276, this may produce depixe-
lization of the resulting image, which is desirable in
certain applications, such as video displays. When dif-
ferent fields appear on the two light valve arrays,
doubled image resolution in both mutually orthogonal
directions may result.
By translating one or both of t~e ligh~ valve
arrays 274 and 276 dynamically, analogously to the embod-
iment of Fig. 8, even greater increases in resolution can
be achieved.
It is appreciated that in all of thP embodi-
ments employing two light valve arrays, the light valve
arrays should be placed optically equidistant from the
objective lens.
Reference is now made to Fig. 11, which is an
illustration of a projector employing two light valve
arrays in accordance with another embodiment of the
present invention.
Light from a light source 3t)~) impinges on a
polarizing beam splitter 302. The resulting two mutually
orthogonally polarized components of the light p and s
are directed via two separate mirrors 3~4 and 3~6 and
respective light valve arrays 3(~8 and 31~) to a polarizing
beam splitter 312.
When a voltage is not applied to light valve
arrays 3(~)8 and 31(), all of the light impinging on polar-
izing beam splitter 312 is directed to an objective lens
. 314, for operation in a normally white mode. When a
voltage is applied to light valve arrays 3(~)8 and 31(~),
some or all of the light impinging on polarizing beam
splitter 312 iS directed in a direction indicated by an
arrow 316. If it is desired to operate in a normally
black mode, an objective lens 318 may be provided to
CA 02234643 1998-04-14
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focus light directed along arrow 316 and to provide an
image thereof.
As in the embodiments of Figs. 7 and 8, by
slightly translating either of the light valve arrays 3~8
and 31~ along respective arrows 32~ and 322 or perpen-
dicularly thereto in the same plane, one may cause two
slightly mutually translated superimposed images of
patterns on the light valve arrays to be projected via
the objective lens. When identical images appear on both
light valve arrays 3~8 and 31~, th~s may produce depixe-
lization of the resulting image, which is desirable in
certain applications, such as video displays. rAhen dif-
ferent fields appear on the two light valve arrays,
doubled image resolution in both mutually orthogonal
directions may result.
By translating one or both of the light valve
arrays 3~8 and 31~ dynamically, analogously to the embod-
iment of Fig. 8, even greater increases in resolution can
be achieved.
It is appreciated that light valve arrays 3~8
and 31~ may be monochromatic or polychromatic. Where the
light valve arrays 3~8 or 31~ are monochromatic, a poly-
chromatic projector may be realized by combining suitably
filtered light passing through three parallel devices of
the type illustrated in Fig. 11.
Reference is now made to Fig. 12, which is an
illustration of a projector employing two light valve
arrays in accordance with yet another embodiment of the
present invention, which provides enhanced contrast. The
embodiment of Fig. 12 may be identical to that of Fig. 11
and identical elements are shown by the same reference
numerals, with the following exception:
Mirror 3~6 is replaced by a polarizing beam
splitter 33~ which directs the s polarized component via
light valve array 31~ as in the embodiment of Fig. 11. In
accordance with a preferred embodiment of the invention,
CA 02234643 l998-04-l4
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the polarizing beam splitter 33(3 is also effective to
filter out a residual p component which impinges thereon
together with the s component, and directs it in a direc-
tion indicated by an arrow 332, thus removing it from the
system and thus enhancing contrast.
Reference is now made to Fig. 13, which is an
illustration of a color projector employing two light
valve arrays in accordance with still another embodiment
of the present invention, which provides enhanced con-
trast. The embodiment oP Fig. 13 may be identic:~l to that
of' Fig. 12 and identical elements are shown by the same
reference numerals, with the following exception:
A color wheel 34~ or any other suitable device
for sequentially transmitting the R, G and B spectral
components of the beam is located intermediate the light
source 3~)() and the polarizing beam splitter 302. This
arrangement can be employed with particular utility when
the light valve arrays 3~)8 and 31() are monochromatic, for
providing a color projector.
Reference is now made to Fig. 14, which is an
illustration of a color projector employing two light
valve arrays in accordance with a further embodiment of
the present invention, which provides enhanced contrast.
The embodiment of Fig. 14 may be identical to that of
Fig. 12 and identical elements are shown by the same
reference numerals, with the following exception:
In order to provide greatly enhanced light
utilization at the light valves 3(~8 and 31(~), prism/lens
combination arrays 35O and 352 are disposed upstream of
respective light valve arrays 3O8 and 311~). The prism/lens
~ combination arrays 35~ and 352 may be of the type de-
scribed and claimed in applicant/assignee's Published
European Patent Application ~)631434.
As seen in Fig. 15, each component of an incom-
ing collimated ray of light 354 is broken down by the
prism/lens array 35~) into bands of different colors,
CA 02234643 l998-04-l4
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16
each of which passes through a separate pixel in light
valve 3~)8. This arrangement has substantial benefits in
terms of light utilization efficiency as described in
applicant/assignee's Published European Patent Applica-
tion (~)6331434, the disclosure of which is hereby incorpo-
rated by reference.
Reference is now made to Fig. 16, which is an
illustration of a color projector employing two light
valve arrays in accordance with still another ~mbodiment
of the present invention. The embodiment of Fig. 16 may
be identical to that of Fig. 11 and identical elements
are shown by the same reference numerals, with the fol-
lowing exception:
In order to provide greatly enhanced light
utilization at the light valves 3(~)8 and 31(~), there are
provided in front of mirror 3t~4 a pair of slightly tilted
dichroic reflectors 360 and 362. Mirror 304 and dichroic
reflectors 36(~ and 362 are together operative to provide
a fan of the separate R, G and B components of light,
each component being angularly separated from the other.
Similarly, there are provided in front of
mirror 3(~)6 a pair of slightly tilted dichroic reflectors
364 and 366. Mirror 3t)6 and dichroic reflectors 364 and
366 are together operative to provide a fan of the sepa-
rate R, G and B components of light, each component being
angularly separated from the other.
The three mutually angularly separated compo-
nents R, G and B impinge on respective lens arrays 368
and 37(~), which are disposed upstream of respective light
valve arrays 308 and 310.
As seen in Fig. 17, each of the R, G and B
components of an incoming collimated ray of light 38(~) is
focused by the lens array 368 through a separ~te pixel
in light valve 3t~)8. This arrangement has substantial
benefits in terms of light utilization efficiency as
described in applicant/assignee's Published European
CA 02234643 l998-04-l4
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Patent Application 06331434, the disclosure of which is
hereby incorporated by reference.
It is appreciated that the embodiments of Figs.
17 may be employed to provide stereo projection
without the need for plural projectors. Reference is
made, for example, to the embodiment of Fig. 11, wherein
light valve arrays 3~8 and 31~ each represent information
to be presented to a separate eye of a viewer, who wears
conventional passive polarized eyeglasses. The
lnformation to be presented to the left eye is provided,
for example, by light valve array 3~8 with a vertical
polarization and the information to be presented to the
right eye is provided, for example, by light valve array
31~ with a horizontal polarization. The passive
polarized eyeglasses in such a case would have vertical
polarization in front of the left eye and horizontal
polarization in front of the right eye.
It is appreciated that for simplicity and
conciseness of description, not all of the standard
components of a projector have been specifically de-
scribed herein. These components include IR an~ UV fil-
ters and fresnel lenses. It is to be understood that all
conventional components of a projector are assumed to be
- included in the projectors of the present invention even
though they are not specifically mentioned herein.
It will be appreciated by persons s~illed in
the art that the present invention is not limited by what
has been particularly shown and described hereinabove.
Rather the scope of the present invention is defined only
by the claims which follow:
