Achromatized transmission-type holographic screen for a multiview stereoscopic image system

Abstract

The main drawback of the use of transmission-type holographic screens is poor color reproduction caused by their high spectral dispersion. For overcoming this drawback, a long, narrow diffusing slit is used as an object when recording the screen. The necessary size and position of the slit relative to the photoplate and to the recording and reconstruction beams are determined by the phase relations of the beams. By use of the slit, holographic screens of 30 cm × 40 cm are recorded with a diverging reference beam and are used to display a multiview full-color stereoscopic image. The images displayed on the screen show no sign of color separation except near the edges of the screen. The image brightness on the screen is high enough that it can be watched in a normally illuminated room.

Full text

Achromatized transmission-type holographic
screen for a multiview stereoscopic image system
Seon-Ho Hwang, V. I. Bobrinev, Jung-Young Son, S. A. Shestak,
and Hyung-Wook Jeon
The main drawback of the use of transmission-type holographic screens is poor color reproduction caused
by their high spectral dispersion. For overcoming this drawback, a long, narrow diffusing slit is used as
an object when recording the screen. The necessary size and position of the slit relative to the photoplate
and to the recording and reconstruction beams are determined by the phase relations of the beams. By
use of the slit, holographic screens of 30 cm 340 cm are recorded with a diverging reference beam and
are used to display a multiview full-color stereoscopic image. The images displayed on the screen show
no sign of color separation except near the edges of the screen. The image brightness on the screen is
high enough that it can be watched in a normally illuminated room. © 1997 Optical Society of America
Key words: Transmission-type holographic screen, multiview full-color stereoscopic image, optical
diffuser.
1. Introduction
In most stereoscopic imaging systems, binocular dis-
parity is adopted for stereoscopic image generation.
1
In these systems, images representing views from both
the left and the right eye are projected in time sequen-
tially or in parallel, respectively, on the viewing screen,
and viewers see the images through a special plate or
a special pair of glasses. When viewers wear the spe-
cial glasses, the optical properties of the images for
each eye should match those of the glasses to direct
each image to the corresponding eye. There are many
stereoscopic viewing glasses of different types. Color
~red or green!filter, polarization ~horizontal or verti-
cal!, optical density ~high or low!, and time sequential
gating with liquid-crystal-display shutters are exam-
ples of stereoscopic viewing glasses.
2
Stereoscopic viewing plates are a more advanced
form of stereoscopic viewing media that do not re-
quire special glasses for viewing. Lenticulars, par-
allax barriers, microlens arrays, and holographic
screens are examples of such plates. These plates
can be classified into three distinct groups on the
basis of their operating roles: ~1!directing left- and
right-side images that are displayed under them to
the viewer’s corresponding eye, e.g., lenticular and
parallax-barrier plates, ~2!forming three-dimensional
images, e.g., a microlens-array plate, and ~3!directing
and displaying images, e.g., a holographic screen.
Among these plates, the lenticular plate is the most
developed stereoscopic viewing plate at present; how-
ever, its viewing zones and depth are limited.
3
The
parallax-barrier plate has low image brightness,
4
and
the microlens-array plate has so far had no form of
manufacture developed.
3
The holographic screen is a kind of holographic
optical element that can work like a mirror,
5
a lens, a
diffuser, or a lens plus diffuser.
6,7
A holographic
screen with mirror or diffuser properties also has an
image-forming capability. The screen directs lights
from the images projected on it to the viewing zone.
The viewing zone is defined as the images of the exit
pupil of the projection lens formed by the screen, and
the positions of the images relative to the holographic
screen are defined by the beam projection angle to the
screen.
The holographic screen has high light efficiency,
multiview properties, and an easy fabrication process
compared with other types of plates. However, as
S.-H. Hwang is with the Electronics and Telecommunications
Research Institute of Korea, Taejeon 305-350, Korea. When this
study was done V. I. Bobrinev and S. A. Shestak were with the
Research and Development Institute of Radio-optics, 34 Ku-
tuzovsky Prospekt, Moscow 121293, Russia. J.-Y. Son and H.-Y.
Jeon were with the Korean Institute of Science and Technology,
P.O. Box 131, Seoul 130-650, Korea. V. I. Bobrinev and S. A.
Shestak are now with the Korea Institute of Science and Technol-
ogy.
Received 9 April 1997.
0003-6935y97y266605-06$10.00y0
© 1997 Optical Society of America
10 September 1997 yVol. 36, No. 26 yAPPLIED OPTICS 6605