1. 12.1 / A. Kurtz
12.1 : Digital Cinema Projection with R-LCOS Displays
Andrew F. Kurtz, Barry D. Silverstein, and Joshua M. Cobb
Eastman Kodak Company, Rochester, New York, USA
Abstract
A digital cinema projector developed by Eastman Kodak
Company, utilizing three JVC QXGA LCDs, and providing 12,000
lumens, 2,000:1 contrast, and 3 Mpixel resolution, is described.
This system, which has a novel optical configuration, wire grid
polarizers and polarization compensators, provides high contrast
at low F#, a large color gamut, and minimal stress birefringence
at high power.
1. Introduction
The future of electronic cinema was dramatically foreshadowed in
1999, when the film “Star Wars: Episode I – The Phantom
Menace” (Lucas Films) was exhibited in Los Angeles and New
York, with two JVC ILA projectors and two Texas Instruments
DLP projectors exhibited in parallel [1,2]. The DLP platform has
since progressed, from a 0.9" chip with 1 MP resolution and
~800:1 system contrast at F/3, to a 1.25" diagonal chip with 2 MP
resolution and ~1800:1 contrast at F/2.4. The JVC ILA projector
provided ~17,000 screen lumens and 1500:1 contrast with F/4.6
optics. However, the ILA projector was assembled with at least
two technologies (2.5" diagonal CRT back written ILA panels and
liquid immersed polarization prisms) which are now considered
obsolete. JVC has continued projector development activities
around their D-ILA reflective liquid-crystal-on-silicon chip
technology [3], including the 5000 lumen QX-1 projector.
Eastman Kodak Company has responded to the emergence of
digital cinema with a multi-faceted effort, including
the development of both enhanced motion picture film
projection [4] and digital cinema projection
technologies. In particular, Eastman Kodak Company,
in cooperation with JVC, has developed a prototype
digital cinema projection system utilizing three JVC
D-ILA QXGA LCOS panels. A complete digital
cinema projection system, from lamp source to
illumination optics; color splitting and combining
optics; LCDs and polarization optics; and imaging
optics; has been designed, built, and tested. This
system, shown in Figure 1, has projected cinema
content on a 45 ft wide screen with bright, high-
contrast images, with wide color gamut and good
uniformity. With 3 Mpixel resolution, the projected
images are sharp, and yet not burdened with visible
pixel structure. This system was successfully
demonstrated at the Entertainment Technology Center
(ETC) in Hollywood in February 2003, to an audience
that included both cinematographers, and executives
and technical staff from the exhibitors, studios, and
laboratories.
2. Imaging Optics
In order to provide the required brightness, the system is equipped
with both high intensity illumination (a 6 kW lamp) and F/2.3
imaging optics. The imaging optical system, shown in Figure 2,
uses an unlikely optical configuration employing intermediate
imaging [5]. In particular, each color channel has a double
telecentric imaging relay that provides a magnified real image in
proximity to the color combining prism. A projection lens and
anamorphic attachment are employed to re-image the overlapped
full color images to the screen. The anamorphic lens converts the
LCD aspect ratio (1.33:1) to the screen formats (“Flat” - 1.85:1
and Cinemascope - 2.39:1) popular in cinema projection.
In a typical LCOS projection system, difficulties are encountered
due to the working distance needed to locate both the polarization
optics and color combining optics in proximity to the LCD panels.
In this system, these problems are overcome by placing the
polarization optics in object space (at the LCD), and the color
combining prism in image space. Although the total number of
optical components are increased by use of the imaging relays, the
projection lens and anamorphic attachment lens are not
constrained by difficult size and working distance requirements,
and thus are greatly simplified as compared to other digital
cinema systems. As a result, the projection lenses have much
shorter focal lengths than seen in other digital cinema systems.
The relays and the projection lens work in combination to provide
a readily converged, nearly distortion free image.
Notably, both the projection and anamorphic imaging lenses are
comparable in cost and complexity to standard cinematic film
projection lenses. It is therefore possible to provide a set of
inexpensive fixed focal length projection lenses, to cover the
range of theatre throw to screen ratios (~1.4-2.7:1) present in the
exhibition industry. Alternately, a smaller set of inexpensive
zoom lenses can be provided. While three imaging relays are
required (one per color), these assemblies can be identical, or
nearly so, and can use standard, lead-free, optical glasses.
SID 04 DIGEST • 1
Figure 1 : the Kodak Digital Cinema Projector
Figure 2 : Intermediate Imaging Optics, V-Prism, and
Projection Lens [5].
ISSN0000-0966X/00/3001-0000-$1.00+.00 © 2004 SID

2. 12.1 / A. Kurtz
2.1 Color Splitting
A key aspect of this design is that the imaging relays magnify the
LCDs at 2X, such that imaging light is F/2.3 at the LCDs and
F/4.6 at the prism. As a result, the design and fabrication of the
projection lenses, the anamorphic attachment lens, and the
combining prism are all eased. This system, as shown in Fig. 2,
preferably uses a V-prism (shown in detail in Figure 3) rather than
the standard X-prism for combining the three-color beams [5].
While X-prisms are compact, they can introduce significant
convergence errors, centerline diffraction, and color shading,
particularly at speeds as fast as F/2.3. Moreover, the X-prism, is
mechanically over-constrained, and thus subject to mechanically
induced stress birefringence. By comparison, the V-prism
provides a simple construction that is easily coated and can be
assembled with stress free interfaces. The resulting V-prisms,
which are fabricated with coating and substrate materials capable
of handling a high heat load, have minimal mechanical or thermal
stress birefringence, such that the combined color beams are very
uniform. Indeed, the V-prisms work well enough that they can be
used both for color separation and color re-combination. The
projector provides a large color gamut, which exceeds that of
typical video systems, and at least meets the standards being
proposed for digital cinema.
Although this system requires a large number of optical
components compared to more conventional designs, the optics
themselves are not exotic, and there are significant design and
manufacturing advantages that are gained. It is believed that this
design approach can be scaled and extended downwards
(particularly for LCD based systems) on a competitive basis into
some (particularly high contrast) lower end markets.
3. Polarization Optics
The market requirements for digital cinema, which require both
high screen brightness (5000-18,000+
lumens) and high frame
sequential contrast (2,000+
:1), burden the polarization optics to
operate at high speed under abusively high light loads. In the case
of the LCDs, where incident power densities can exceed 6 W/cm2
,
it is critical to mount the devices with minimal stress, while
providing careful control of the package temperature. Likewise,
the polarizers must be very robust, while providing high contrast
with fast optical beams.
The projector is equipped with three JVC DILA QXGA displays,
as they are high resolution, large diagonal, VAN mode devices
that can satisfy the requirements for digital cinema. To further
satisfy these requirements, the projector utilizes visible
wavelength wire grid polarizers, which have been developed by
Moxtek Inc. of Orem UT [6]. The system was initially conceived
using wire grid polarizers, because of their superior contrast, wide
angular response, broadband visible wavelength response, and
innate robustness (particularly relative to thermal loading), as
compared to alternate technologies such as the MacNielle prism.
Moxtek has continuously improved these devices, providing both
protective coatings and improved flatness for imaging
applications [7]. Moreover, improvements to wire grid polarizers
are possible, for example to enhance blue contrast or to increase
reflected and transmitted contrast, by decreasing the wire pitch or
with multi-layer structures [8] (see Figure 4).
3.1 Modulation Optics and Wire Grid Polarizers
Since visible wavelength wire grid polarizers became available
from Moxtek, a variety of projection system designs [9-14] have
been proposed, including single chip, two chip, and three chip
configurations. As a three-chip system, the projector is provided
with a modulation optical sub-system for each color channel,
which is designed around a wire grid polarization beamsplitter.
The wire grid polarization beamsplitter, which has a transmitted
contrast >1,000:1 at F/2.3, is a key enabling technology in this
design.
As shown in Figure 5, this system uses a modulation optical
system that includes a wire grid polarization beamsplitter, a pre-
polarizer and a polarization analyzer. To attain the high contrast
required for digital cinema, an assembly of at least two polarizers
is required. It has been shown that the modulation optical system
of Fig. 5 is capable of very high projected contrast (>40,000:1),
when tested with a mirror and waveplate (instead of with an
LCD). To mitigate against thermal loading concerns, all three
polarizers are preferably wire grid devices.
The wire grid polarization beamsplitter is a fairly unobtrusive
component, relative to its’ impact on the optical system. However,
design choices can be made to further reduce any impact. For
example, to avoid the aberrations that result from transmission
through a tilted plate, the wire grid polarization beamsplitter is
preferably used in reflection into the imaging system. Likewise, to
attain the target system contrast levels, de-polarization effects
from the wire grid polarizers should be minimized. Most
• SID 04 DIGEST2
Figure 5 : The modulation optical system [13, 15].
Figure 4 : A multi-layer wire grid polarizer [8].
Figure 3 : The V-prism Combiner

3. 12.1 / A. Kurtz
importantly, the wire grid polarization beam splitter is best
oriented with the sub-wavelength wires facing the LCD [12, 13],
as de-polarization from thermal stress induced birefringence is
minimized. Otherwise, system contrast can be reduced by as
much as ~10X.
Due to their wide angular response, particularly as compared to
the traditional MacNielle prism, wire grid polarizers have been
perceived as not contributing any skew ray de-polarization effects.
Indeed, the wire grid polarization beamsplitter can be considered
to be partially self compensating [15], when it is used in both
transmission and reflection, such as in the modulation optical
system of Fig. 5. In particular, this is because the wire grid
polarization beamsplitter can be classified as an E-type polarizer
in transmission (transmits the extraordinary ray) and O-type
polarizer in reflection (reflects the ordinary ray). In actuality, wire
grid polarizers still can cause small skew ray de-polarization
effects [15], which can become important as LCOS projection
systems strive for ever higher levels of contrast and brightness
performance.
3.2 Polarization Compensation
As shown in Fig. 5, this system is equipped with a polarization
compensator, which is nominally located between the LCD and
the wire grid polarization beamsplitter. This compensator can be
designed to provide polarization state correction for the LCD
panel, the wire grid polarization beamsplitter, or for the two in
combination [13, 15]. The compensator, which can be fabricated
from stretched polymer materials, liquid crystal polymers, or
inorganic materials, typically provides a combination of in-plane
(A-plate) and out-of-plane (C-plate) retardances. With respect to
the LCD panel, the in-plane retardance is utilized to correct any
residual birefringence within the device, while the out-of plane
retardance corrects for angular response variations (F#
dependent). Compensation for the wire grid polarizers may also
have both A-plate and C-plate portions, and is largely F#
dependent.
To better appreciate the value of polarization compensation and its
relevance to the modulation optical system of Fig. 5, Figure 6
shows plots of contrast vs. illumination F# under different test
conditions as measured in a bench set-up. Note that low contrast
(~400:1) is achieved when a VAN LCOS panel is used with the
polarizers, but without any polarization compensation (see plot
labeled “uncompensated”). However, when an optimized
compensator is used, the performance improves dramatically
(2,100:1 CR at F/2.3, per plot labeled “compensated”). Contrast
might be expected to increase more dramatically vs. F# than
shown, but the measured contrast depends on the actual display
and compensator, as well as the interaction of the diffracted orders
and the collection aperture (fixed at F/2.3 for this data).
In actual use, the compensator is mounted in close proximity to
the LCOS panel, and is then rotated to optimize the contrast
performance, on the basis of the peak contrast and the contrast
uniformity achieved. While the bench measurements and the
system measurements of contrast don’t correlate exactly, a
measured white light on screen contrast above 2,200:1 at F/2.3 is
typical for this system.
3.3 Wire Grid Polarizers As Compensators
It has also been demonstrated [16] that system contrast can be
improved significantly by means of a small in-plane rotation (see
Fig. 7) of the wire grid polarization beamsplitter. While rotation
of the other wire grid polarizers in the system can also provide
improvements, the gains are much less dramatic than occur with
rotation of the wire grid polarization beamsplitter. As an example,
Figure 6 provides a plot, labeled “WG Polz. Rotation”, in which
an LCOS display was tested for contrast, with wire grid rotation
used for compensation. The resultant contrast is much better than
the uncompensated case. The improvement likely is due to a
combination of effects, involving alignment of the polarizer to the
actual polarization axis of the incident light, and an interaction
with the form birefringent retardance of the sub-wavelength
structure.
Another example is shown in Fig. 6, in which an LCOS panel was
tested in combination with a polarization compensator and wire
grid rotation compensation. The result (see plot labeled “Comp.
with Rotation”) is slightly better than the case with the LCOS
panel used with a compensator alone. In effect, wire grid polarizer
rotation can be used as polarization compensation mechanism
(like an A-plate) for LCD displays, either in combination with
other compensators, or as a replacement for the compensators
(particularly at speeds of F/4 and greater).
4. System Performance and Potential
As shown in Table 1, this prototype system provides the basic
performance necessary for digital cinema projection. However, it
should be understood that the system performance given in Table
1 does not represent the pinnacle of this design.
To begin with, the proposed standards developed by SMPTE and
the studio sponsored Digital Cinema Initiatives Group (DCI) are
advocating a two tier resolution standard, with an initial “2K”
horizontal resolution and a migratory target “4K” resolution. As
SID 04 DIGEST • 3
Modulation CR vs. F#
0
500
1000
1500
2000
2500
3000
2 4 6 8 10 F#
SequentialContrast
Uncompensated
WG Polz.
Rotation
Compensated
Comp. with
Rotation
Figure 6 : Polarization Contrast vs. F# [15, 16].
Figure 7 : Wire Grid Rotation for Polarization
Compensation [16].

4. 12.1 / A. Kurtz
experimental 4K LCOS panels have been fabricated by JVC, and
then tested in projection [17], the Kodak projector clearly has the
potential to migrate to higher resolutions.
Similarly, the original target >1,000;1 contrast was beyond the
performance of commercial electronic projectors when the project
began, and seemed barely achievable. Subsequently, both this
system and the TI DLP based digital cinema systems have
achieved ~2,000:1 contrast levels. Furthermore, this system, with
improved components, has already demonstrated ~3,000:1
projected white light contrast. Thus, it seems likely that LCOS
based projection will eventually match the 5,000-10,000:1
contrast provided by the traditional film system. (The difference
between 2,000:1 ~7,000:1 is both perceptible and significant.)
Other performance metrics, such as system brightness and ANSI
contrast can also be improved. For example, the system can be
extended to illuminate with 15,000+
screen lumens, thus enabling
the use of 50+
ft. wide screens. Alternately, the system can be
configured to use the Cermax style xenon lamps, rather than the
traditional bulb lamp, for improved brightness and efficiency.
5. Conclusions
This system represents the first demonstration that reflective
LCOS micro-displays are a viable technology for use in digital
cinema projection systems, as the system provides the brightness,
contrast, and resolution necessary to satisfy both the consumer
and the motion picture industry. In particular, it has been
demonstrated that R-LCOS panels and the associated polarization
optics can function in the harsh environment of a high-lumen
projection system. Additionally, it has been shown that
competitive LCOS based optical designs are achievable for digital
cinema and other high lumen projection applications.
6. Acknowledgements
The authors wish to recognize the significant contributions and
successes of the entire projector team. In particular, the dedicated
efforts of Gary Nothhard, Xiang-Dong Mi, Franklin Ehrne, David
Nelson, James Stoops, William Markis, and Richard Wagner
deserve special mention. The Entertainment Imaging Division,
and in particular, Richard Sehlin and Leslie Moore, also merit
recognition for their continuing support.
7. References
[1] L. Hornbeck, D. Darrow, H. Pettitt, B. Walker, and B.
Werner, DLP Cinema Projectors – Enabling Digital Cinema,
SID Digest 2000, pgs. 314-317.
[2] R. Sterling and W. Bleha, Electronic Cinema Using ILA
Projector Technology, SID Digest 1999, pgs. 216-219.
[3] R. Sterling and W. Bleha, DILA Technology for Electronic
Cinema, SID Digest 2000, pgs. 310-313.
[4] C. DuMont, A. Kurtz, B. Silverstein, and D. Kirkpatrick,
Design Improvements for Motion Picture Film Projectors,
SMPTE Journal, vol. 110, pp. 785-791, Nov. 2001.
[5] J. Cobb and D. Kessler, Projection Apparatus using Spatial
Light Modulator with Relay Lens and Dichroic Combiner,
U.S. Patent 6,676,260, 2004.
[6] D. Hansen, R. Perkins, and E. Gardner, Broad Band Wire
Grid Polarizing Beam Splitter for use in the Visible
Wavelength Region, U.S. Patent 6,243,199, 2001.
[7] D. Hansen, E. Gardner, R. Perkins, M. Lines, and A.
Robbins, The Display Applications and Physics of the
ProFlux Wire Grid Polarizer, SID 2002 Digest, pgs. 730-733.
[8] A. Kurtz, S. Ramanujan, and X.D. Mi, Wire Grid Polarizer,
US Patent 6,532,111, 2003.
[9] D. Hansen, R. Perkins, E. Gardner, and M. Lund, Image
Projection System with a Polarizing Beam Splitter, U.S.
Patent 6,234,634, 2001.
[10] S. Arnold, E. Gardner, D. Hansen, and R. Perkins, An
Improved Polarizing Beamsplitter LCOS Projection Display
Based on Wire-Grid Polarizers, SID Digest 2001, pgs. 1282-
1285.
[11] E. Gardner and D. Hansen, An Image Quality Wire-Grid
Polarizing Beam Splitter, SID Digest 2003, pgs. 62-65.
[12] J. Shimizu, P. Janssen, and S. McClain, Digital Image
Projector with Oriented Fixed Polarization Axis Polarizing
Beamsplitter; U.S. Patent 6,511,183, 2003.
[13] A. Kurtz, J. Cobb, D. Kessler, B. Silverstein, and M.
Harrigan, Digital Cinema Projector, U.S. Patent 6,585,378,
2003.
[14] C. Pentico, M. Newell, and M. Greenberg, Ultra High
Contrast Color Management System for Projection Displays,
SID Digest 2003, pgs. 130-133.
[15] X. D. Mi, A. Kurtz, and D. Kessler, Display Apparatus using
a Wire Grid Polarizing Beamsplitter with Compensator, U.S.
Patent Pub. No. 2003/0128320, 2003.
[16] B. Silverstein, G. Nothhard, A. Kurtz, and X. D. Mi,
Projection Display using a Wire Grid Polarization
Beamsplitter with Compensator, U.S. Patent Pub. No.
2003/0227597, 2003.
• SID 04 DIGEST4
Light Source 6 kW Xenon arc
Brightness/luminous Output 12,000 screen lumens
Screen Luminance 12 ft-L
Screen Uniformity ~85 %
Frame Sequential Screen
Contrast (white)
~2,200:1
ANSI Contrast ~150:1
Color Temperature ~ 5500 to 6100 o
K
Imager JVC QXGA DILA; 1.3" diag., 2048 x
1536 px, 1.33:1 aspect ratio
Imager Aperture Ratio (“Flat” - 1.85:1) with anamorphic lens
Light Collection F/2.3 at LCDs
Projection Lens 2.0:1 theatre to screen ratio; others can
be readily designed
Image Distortion < 2%
Frame Rate 24 fps effective, 96 Hz repeated
Data 10 bits log/color, 12 bit resolution
Data Standards supported SMPTE 292M, HDTV, SDTV
Table 1 : Digital Cinema Projector Technical Specifications

5. 12.1 / A. Kurtz
[17] K. Hamada, M. Kanazawa, I. Kondoh, F. Okono, Y. Haino,
M. Sato, and K. Doi, A Wide Screen Projector of 4k x 8k
Pixels, SID 2002 Digest, pgs. 1254-1257.
SID 04 DIGEST • 5

6. 12.1 / A. Kurtz
[17] K. Hamada, M. Kanazawa, I. Kondoh, F. Okono, Y. Haino,
M. Sato, and K. Doi, A Wide Screen Projector of 4k x 8k
Pixels, SID 2002 Digest, pgs. 1254-1257.
SID 04 DIGEST • 5