Liquid crystal cells – elements and systems – Liquid crystal system – Stereoscopic
Reexamination Certificate
2001-12-27
2004-11-09
Parker, Kenneth (Department: 2871)
Liquid crystal cells, elements and systems
Liquid crystal system
Stereoscopic
C349S191000, C349S183000
Reexamination Certificate
active
06816207
ABSTRACT:
This application claims the benefit of Korean Patent Application No. 2001-22846, filed on Apr. 27, 2001, which is hereby incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to liquid crystal display devices. More particularly, it relates to an apparatus and method of making three-dimensional (3-D) displays that are capable of viewing a 3-D image.
2. Discussion of the Related Art
In normal vision human eyes perceive views of the world from two different perspectives due to their spatial separation. The spatial separation between typical eyes is about 65 mm. In order to assess the distance between objects, the brain integrates the two perspectives obtained from each eye. In order to provide a display, which is effective in displaying 3-D images, it is necessary to recreate this situation to the observer. That is, supplying a so-called “stereoscopic pair” of images to the observer's eyes.
Most 3-D displays may be classified into two types: stereoscopic and auto stereoscopic. Stereoscopic displays typically display both of the images over a wide viewing area. The views are encoded by color, polarization state and time of the display. A filter system of glasses worn by the observer separates the views, thereby each eye sees only the view that is intended for it. That is the right and left eyes have different views.
Autostereoscopic displays present a spatial image to the viewer without the use of glasses, goggles or other viewing ads. Instead, the two views are only visible from defined regions of space.
A “viewing region” is a term described as the region of space in which an image is visible across the whole of the display active area. If the observer is situated such that one eye is in one viewing region and the other eye is in the other viewing region, then a correct set of views is seen and a 3D image is perceived by the observer.
In autostereoscopic displays of the “flat panel” type the viewing regions are formed by a combination of the picture element structures (pixels) and optical elements, generically termed a parallax optic. An example of such an optic element is a parallax barrier. This element is a screen with vertical transmissive slits separated by opaque barrier regions.
As a method of displaying the 3-D images without using viewing aids the lenticular method and a parallax barrier method have been conventionally proposed. The lenticular method and the parallax barrier method are stereoscopic image display apparatuses that do not require the use of polarization glasses, shutter glasses, goggles or other viewing ads. In these apparatuses, special optical elements such as lenticular lenses or parallax barriers are generally placed on the front surface sides of display devices. These special optical elements are relatively inexpensive and exhibit high productivity. A simple autostereoscopic image display apparatus can be easily formed by a combination of such an optical elements with a 2D display. Accordingly, these methods are especially suited for use with liquid crystal display devices (LCDs) and the like.
The parallax barrier method is a method in which a parallax barrier comprising an opaque material is slotted with a series of regularly spaced vertical slits and is arranged short of a display screen to cause parallax and to obtain the 3-D images. In the conventional parallax barrier method, a retardation film made of a polymer, a first polarizer and a second polarizer are utilized. Specifically, the retardation film includes a plurality of first regions and a plurality of second regions, these regions are utilized for carrying out an image-splitter method.
FIG. 1A
is a global view of a parallax barrier according to a related art, and
FIG. 1B
is a cross-sectional view of the parallax barrier of FIG.
1
A.
The parallax barrier shown in
FIGS. 1A and 1B
includes a polarization modifying layer
42
and polarizers
44
and
46
in the form of polarizing sheets. The polarization modifying layer
42
includes a patterned retarder layer, which is made by the methods illustrated in
FIGS. 2A
to
2
E. Also, the polarization modifying layer
42
comprises first regions “C” in the form of parallel elongated slit regions. Specifically, these regions are arranged in such a manner to rotate linear polarization of incoming light
41
. The first regions “C” are separated by second regions “D” which are arranged not to affect the polarization of the incoming light
41
.
The first polarizer
44
, which may include the output polarizer of an associated LCD, has a polarizing axis
44
a
. This axis is oriented at 45 degrees. This is typical of LCD output polarizers. such as the twisted nematic type polarizer. The optic axes of
42
a
in the first regions “C” are oriented at 90 degrees, and the optic axes
42
b
of the second regions “D” are aligned at 45 degrees so as to be parallel to the polarization vector of light emitted from the first polarizer
44
. The second polarizer
46
has its polarizing axis
46
a
oriented at 45 degrees. The polarizing axis
46
a
of the second polarizer
46
is orthogonal to the polarizing axis
44
a
of the first polarizer
44
.
In
FIGS. 1A and 1B
, when the incident light
41
passes through the first polarizer
44
, it is polarized at +45 degrees relative to the vertical axis of the polarization modifying layer
42
. The polarization modifying layer
42
has strip-shaped first regions “C” and strip-shaped second regions “D”. The polarization of the light passing through the second regions “D” are not affected, therefore, the second polarizer
46
extinguishes light. This happens because the second polarizer
46
has a polarizing direction indicated at
46
a
, which is substantially orthogonal to the polarization direction of the light passing through the second regions “D”. After the incident light
41
passes through the first polarizer
44
, the polarization of the light passing through the first regions “C” are rotated by 90 degrees and as a result, this light passes through the second polarizer
46
. Accordingly, the aforementioned device functions as a paraliax barrier.
The polarization modifying layer
40
is made by forming a layer of reactive mesogen, such as RM257, available from MERCK® UK. Utilizing standard photolithographic techniques the layer is then patterned.
FIGS. 2A
to
2
E are cross-sectional views illustrating the steps of making the polarization modifying layer
40
of FIG.
1
A.
In
FIG. 2A
, a substrate
34
is divided into two regions, a plurality of first regions “C” and a plurality of second regions “D.” Thereafter, an alignment layer
36
is formed on the substrate
34
as shown in FIG.
2
B. The alignment layer
36
comprises rubbed polyimide, polyamide, or silicon oxide, which has a first rubbing direction
38
a.
In
FIG. 2C
, a photo resist
39
is applied to the alignment layer
36
having the first rubbing direction. A mask
40
that has light-transmitting portions “E” and light-shielding portions “F” selectively exposes the photo resist
39
. This exposure is accomplished by using known photolithographic techniques. Each of the light-transmitting portions correspond to each of the first regions “C” of the substrate
34
, and each of the light-shielding portions correspond to each second regions “D” of the substrate
34
. Then the exposed portions of the photo resist
39
associated with the light-transmitting portions “C” are removed, thereby exposing the first regions “C” of the underlying alignment layer
36
as shown in FIG.
2
D. Then, the substrate
34
having the alignment layer
36
and photo resist
39
are thermal-heated in a heating apparatus. The substrate assembly is then rubbed in a second rubbing direction
38
b
in order to produce an alignment layer
37
having a spatially varying alignment direction. As a result, first alignment portions
37
a
corresponds to each of the first regions “C” having a second rubbing direction
38
b
, while the second alignment portions
37
b
corresponds to each of
LG.Philips LCD Co. , Ltd.
Parker Kenneth
LandOfFree
Autostereoscopic display apparatus and method of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Autostereoscopic display apparatus and method of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Autostereoscopic display apparatus and method of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3346237