Liquid crystal cells – elements and systems – Liquid crystal system – Stereoscopic
Reexamination Certificate
2000-04-12
2001-02-13
Sikes, William L. (Department: 2871)
Liquid crystal cells, elements and systems
Liquid crystal system
Stereoscopic
C349S117000, C430S020000
Reexamination Certificate
active
06188451
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an optical rotatory device for use in a display device such as a CRT (Cathode Ray Tube) and a liquid crystal display panel (Liquid Crystal Display) adjusting a polarization direction of outgoing light from a pixel of the display device so as to realize a stereoscopic image, and also relates to a manufacturing method of the optical rotatory device and an image display device using thereof.
BACKGROUND OF THE INVENTION
Various stereoscopic image display devices for obtaining a stereoscopic image from a flat display has been proposed. For such a stereoscopic image display device which displays a stereoscopic image, the following three systems are widely adopted other than the hologram system.
According to the first system, a single image display device alternatively displays a right eye-use image and a left eye-use image in a time sharing manner. This system is arranged so that a stereoscopic image can be obtained based on the fact that an observer wears shutter spectacles whose right and left lenses open and close alternatively in synchronism with the alternating of the images.
According to the second system, a right eye-use image and a left eye-use image are alternatively displayed in a stripe manner by a single image display device. Then, a lenticular lens or slits, provided in a vicinity of the display device, assigns the displayed image to the right and left eyes respectively.
The third system is referred to as a polarizing spectacles system. This system is arranged so that planes of polarization of outgoing light from a right eye-use pixel and a left eye-use pixel are orthogonal, and image information of the right eye-use pixel and the left eye-use pixel are directed to the right and left eyes by polarizing plates provided to the spectacles worn by the observer to be perceived by the respective eyes. Note that, in this system, clockwise and anti-clockwise circularly polarized light may be used instead of the orthogonal planes of polarization.
The described three systems are based on a principle in which depth perception is organized by separately displaying parallax of right eye-use image and left eye-use image so as to be perceived by the respective eyes of the observer.
The following will describe respective characteristics of the three stereoscopic image systems.
According to the first system, a stereoscopic image displaying can be carried out by a single display device, thereby ensuring that the resolution of the display device can be prevented from lowering, and a stereoscopic image display region is not limited. Nevertheless, because the spectacles to be worn by the observer are heavy due to the shutter function, it is not suitable for use in a long period of time. Further, the spectacles with such function are expensive.
According to the second system, a stereoscopic image can be observed without wearing spectacles. However, the second system has a drawback in that the observer is required to fix his or her head since the stereoscopic image display region is limited.
According to the third system, it is required for the observer to wear spectacles with a specific function, yet the spectacles required in the third system are not as expensive and complex as that used in the first system, i.e., the spectacles of the third system are lighter and inexpensive. Further, a stereoscopic image can be observed by a plurality of observers with the respective spectacles, thereby having an advantage over the second system in that the stereoscopic image display region is not limited.
However, in the third system, in order to display images having different polarization directions, a system for combining images produced by two display devices or two projectors with a half mirror or a polarizing mirror is widely adopted. Consequently, the third system has a drawback in that the cost of the display device becomes high due to an increase in the number of constituting components, and therefore the third system is not suitable for home-use.
As a countermeasure, a polarizing plate (micro polarizing plate) composed of two types of polarizing plates which are arranged in a mosaic or a stripe manner on a single plane and their polarizing axes are orthogonal to each other has been invented. The polarizing plate of this type permits a single display device to display both the right eye-use image and the left eye-use image.
For example, Japanese Unexamined Patent publication No. 184929/1983 (Tokukaisho 58-184929) discloses a micro polarizing plate composed of two types of plane polarizing plates which are arranged in a mosaic manner so that the polarizing axes are orthogonal to each other. According to the above publication, the micro polarizing plate is provided in front of the display device, and an image is allowed to pass through spectacles having a pair of polarizing plates whose polarizing axes are orthogonal to each other. As a result, the right eye-use image and the left eye-use image are separated by the polarizing plates to be perceived by the respective eyes of the observer, thereby realizing a stereoscopic image.
Here, as the display device, a CRT (Cathode Ray Tube) or a liquid crystal panel (Liquid Crystal Display), etc. is adopted. In the case of adopting the CRT, the micro polarizing plate is provided in front of a display tube. In contrast, in the case of adopting the liquid crystal panel, since polarizing plates are already provided on the both sides of the liquid crystal panel, the polarizing plate on the side of the observer, or the polarizing plates on the side of the observer as well as on the side of a backlight are replaced with the micro polarizing plates.
FIG. 10
illustrates an arrangement of a stereoscopic image display device in which a liquid crystal panel is adopted as a display device, and two types of polarizing plates are arranged in a stripe manner in a horizontal row on both surfaces of the liquid crystal panel such that the polarizing axes of the two types of polarizing plates are orthogonal to each other for each row.
A stripe pitch of the two types of polarizing plates in a vertical column direction is substantially equal to a pixel pitch of a liquid crystal panel
51
in the vertical column direction. A left eye-use image information display region
52
and a right eye-use image information display region
53
are formed alternatively in the vertical column direction. With this arrangement, when viewed with polarizing spectacles
54
, image information of the left eye-use image information display region
52
and the right eye-use image information display region
53
are separated by the polarizing spectacles
54
to be perceived by the respective eyes of the observer, thereby creating a stereoscopic image from the displayed image.
A method for manufacturing the micro polarizing plate, for example, is disclosed in U.S. Pat. No. 5,327,285 in detail. The following will describe the method for manufacturing the micro polarizing plate disclosed in the above U.S. Patent referring to FIG.
11
(
a
) through FIG.
11
(
d
).
Firstly, as shown in FIG.
11
(
a
), a polarizing plate
62
is attached to a glass substrate
61
. As the material of the polarizing plate
62
, uniaxially extended PVA (polyvinyl alcohol) dyed with iodine is widely adopted; nonetheless, other materials may be substituted therefor. Secondly, as shown in FIG.
11
(
b
), a photoresist
63
is applied in such a manner that the photoresist
63
is patterned on every other row, e.g., in a stripe manner, in the same interval as the pixel pitch. Here, for example, P
1
in FIG.
11
(
b
) indicates the width of a pixel of the right eye-use image information, and P
2
in FIG.
11
(
b
) indicates the width of a pixel of the left eye-use image information.
Thirdly, as shown in FIG.
11
(
c
), the polarizing plate
62
is decolorized with potassium hydroxide (KOH) etc. by using the photoresist
63
as a mask to form a non-polarizing region
64
. Instead, the polarizing region may be formed by (1) using an undyed substrate as the polarizing plate
62
Fujii Akiyoshi
Hamada Hiroshi
Neuner, Esq. George W.
Nguyen Duan
Sharp Kabushiki Kaisha
Sikes William L.
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