U.S. patent application number 13/357706 was filed with the patent office on 2012-06-07 for stereoscopic display device and display method.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Rieko Fukushima, Yuzo Hirayama, Tatsuo Saishu, Kazuki Taira.
Application Number | 20120139911 13/357706 |
Document ID | / |
Family ID | 34415647 |
Filed Date | 2012-06-07 |
United States Patent
Application |
20120139911 |
Kind Code |
A1 |
Saishu; Tatsuo ; et
al. |
June 7, 2012 |
STEREOSCOPIC DISPLAY DEVICE AND DISPLAY METHOD
Abstract
A stereoscopic display device of an embodiment includes a
display device having pixels developing either one color of red,
green and blue. A vertical period of pixel rows comprising the
pixels arranged in one row in a lateral direction is three times a
lateral period of the pixels, the pixels developing red, green and
blue are alternately arranged in a lateral direction in the same
row, the pixels in one row of two rows adjacent in a vertical
direction are arranged such that lateral positions thereof are
shifted to the pixels in the other row by 1/2 of the lateral period
of the pixels, the pixels in rows adjacent in the same column
through one row interposed therebetween are the pixels developing
different colors of red, green and blue, and an average value of
pitches of the elemental images is larger than a width of pieces of
the pixels.
Inventors: |
Saishu; Tatsuo; (Tokyo,
JP) ; Fukushima; Rieko; (Tokyo, JP) ; Taira;
Kazuki; (Tokyo, JP) ; Hirayama; Yuzo;
(Kanagawa-Ken, JP) |
Assignee: |
Kabushiki Kaisha Toshiba
Tokyo
JP
|
Family ID: |
34415647 |
Appl. No.: |
13/357706 |
Filed: |
January 25, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12926136 |
Oct 27, 2010 |
8125513 |
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13357706 |
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10935626 |
Sep 8, 2004 |
7834903 |
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12926136 |
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Current U.S.
Class: |
345/419 |
Current CPC
Class: |
G02B 27/0025 20130101;
G09G 2300/0443 20130101; H04N 13/305 20180501; H04N 13/351
20180501; H04N 13/317 20180501; G02B 30/27 20200101; H04N 13/31
20180501; H04N 13/324 20180501 |
Class at
Publication: |
345/419 |
International
Class: |
G06T 15/00 20110101
G06T015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 8, 2003 |
JP |
2003-315356 |
Claims
1-8. (canceled)
9. A stereoscopic display device comprising: a display device
having pixels developing either one color of red, green and blue
which are disposed within a display plane; and a beam controlling
element which is disposed at the front of the display device and
has a plurality of apertures or a plurality of lenses having an
optical opening portion extending linearly in vertical direction,
controlling beam directions from the pixels to divide the display
plane of the display device into elemental images corresponding to
the respective apertures or lenses of the beam controlling element,
wherein a vertical period of pixel rows comprising the pixels
arranged in one row in a lateral direction is three times a lateral
period of the pixels, the pixels developing red, green and blue are
alternately arranged in a lateral direction in the same row, the
pixels in one row of two rows adjacent in a vertical direction are
arranged such that lateral positions thereof are shifted to the
pixels in the other row by 1/2 of the lateral period of the pixels,
the pixels in rows adjacent in the same column through one row
interposed therebetween are the pixels developing different colors
of red, green and blue, and an average value of pitches of the
elemental images is larger than a width of 18n (n=1, 2, 3 . . . )
pieces of the pixels, and a lateral pitch of the beam controlling
element is equal to a width of 18n pieces of the pixels.
10. A stereoscopic display device according to claim 9, wherein the
total number of the elemental images is even number and the
elemental images are arranged within the whole display plane of the
display device symmetrically to left and right, and a boundary of
the elemental images at a center position within the whole display
plane in the lateral direction is set at the middle between pixel
centers of two of the pixels closest to each other in an oblique
direction of rows adjacent in a vertical direction.
11. A stereoscopic display device according to claim 9, wherein
only two pixels developing the same color are arranged so as to be
continuously adjacent to each other in an oblique direction.
12. A stereoscopic display device according to claim 9, further
comprising: means for, by an effective pixel with a generally
square shape comprising 6n.times.18n (n=1, 2, 3, . . . ) pixels
arranged in a vertical direction and in a horizontal direction,
applying the same parallax image information to 3n pixels arranged
in a straight line in the same vertical direction as an extending
direction of the opening portion of the beam controlling element
and in the same position in a horizontal direction to display image
signals as the total of 36n parallaxes at a stereoscopic image
display time ; and means for, by an effective pixel with a
generally square shape comprising 3 pixels of red, green and blue
arranged laterally, ignoring a lateral positional deviation by 1/6
an effective pixel width and regarding the effective pixel as a
square arrangement to display image signals at a flat image display
time where the beam controlling element has been detached or a
function thereof has been invalidated.
13. A stereoscopic display device according to claim 9, wherein,
when the number of pixels in a vertical direction is not a multiple
of 6 or when the number of the effective pixels in the vertical
direction at a stereoscopic display time is not coincident with a
standard such as VGA, XGA or the like, an excess pixel row portion
is uniformly arranged at upper portion and a lower portion or is
collectively arranged at an upper portion or a lower portion, a
pattern figure serving as a guide for a stereoscopic view is
displayed at the excess portion.
14. A stereoscopic display device according to claim 9, wherein,
when the number of pixels in the lateral direction is not a
multiple of 18 or when the number of the effective pixels in the
lateral direction at a stereoscopic display time is not coincident
with a standard such as VGA, XGA or the like, an excess pixel
column portion is uniformly arranged symmetrically to left and
right so that a pattern figure serving as a guide for stereoscopic
view or an images with burred images at end portions thereof is
displayed on the excess portion.
15. A stereoscopic display device according to claim 9, wherein
pixels with the same color closest to each other in adjacent rows
in the display device are driven in the same field by image signals
with different polarities.
16. A stereoscopic display device according to claim 9, wherein
pixels closest to each other in the same column in the display
device are driven in the same field by image signals with different
polarities.
17. A stereoscopic display device comprising: a display device
having pixels developing either one color of red, green and blue
which are disposed within a display plane; a beam controlling
element which is disposed at the front of the display device and
has a plurality of apertures or a plurality of lenses having an
optical opening portion extending linearly in vertical direction,
controlling beam directions from the pixels to divide the display
plane of the display device into elemental images corresponding to
the respective apertures or lenses of the beam controlling element;
and a diffusion layer having a haze of 20 or more to 70 or less,
which is arranged between a pixel plane of the display device and
the beam controlling element, wherein a vertical period of pixel
rows comprising the pixels arranged in one row in a lateral
direction is three times a lateral period of the pixels, the pixels
developing red, green and blue are alternately arranged in a
lateral direction in the same row, the pixels developing red, green
and blue are alternately arranged in a vertical direction in the
same column, and a pitch of the elemental images is equal to a
width of 9n (n=1, 2, 3 . . . ) pieces of the pixels, and a lateral
pitch of the beam control element is smaller than the width of the
9n pieces of the pixels.
18. A stereoscopic display device according to claim 17, wherein
boundaries of all the elemental images are set at middles between
two pixel centers of the pixels closest to each other in an oblique
direction of rows adjacent in a vertical direction, and the total
number of the elemental images are even number and the elements
images are arranged symmetrically to left and right within the
whole display plane.
19. A stereoscopic display device according to claim 17, further
comprising: means for, by an effective pixel with a generally
square shape comprising 3n.times.9n (n=1, 2, 3, . . . ) pixels
arranged in a vertical direction and in a horizontal direction,
applying the same parallax image information to 3n pixels arranged
in a straight line in the same vertical direction as an extending
direction of the opening portion of the beam controlling element
and in the same position in a horizontal direction to display image
signals as the total of 9n parallaxes at a stereoscopic image
display time; and means for, by an effective pixel with a generally
square shape comprising 3 pixels of red, green and blue arranged
laterally, displaying image signals at a flat image display time
where the beam controlling element has been detached or a function
thereof has been invalidated.
20. A stereoscopic display device according to claim 17, wherein,
when the number of pixels in a vertical direction is not a multiple
of 3 or when the number of the effective pixels in the vertical
direction at a stereoscopic display time is not coincident with a
standard such as VGA, XGA or the like, an excess pixel row portion
is uniformly arranged at upper portion and a lower portion or is
collectively arranged at an upper portion or a lower portion, a
pattern figure serving as a guide for a stereoscopic view is
displayed at the excess portion.
21. A stereoscopic display device according to claim 17, wherein,
when the number of pixels in the lateral direction is not a
multiple of 9 or when the number of the effective pixels in the
lateral direction at a stereoscopic display time is not coincident
with a standard such as VGA, XGA or the like, an excess pixel
column portion is uniformly arranged symmetrically to left and
right so that a pattern figure serving as a guide for stereoscopic
view or an images with burred images at end portions thereof is
displayed on the excess portion.
22. A stereoscopic display device according to claim 17, wherein
pixels with the same color closest to each other in adjacent rows
in the display device are driven in the same field by image signals
with different polarities.
23. A stereoscopic display device according to claim 17, wherein
pixels closest to each other in the same column in the display
device are driven in the same field by image signals with different
polarities.
24.-31. (canceled)
32. A display method using a stereoscopic display device according
to claim 9, the display method comprising: by an effective pixel
with a generally square shape comprising 6n.times.18n (n=1, 2, 3, .
. . ) pixels arranged in a vertical direction and in a horizontal
direction, applying the same parallax image information to 3n
pixels arranged in a straight line in the same vertical direction
as an extending direction of the opening portion of the beam
controlling element and in the same position in a horizontal
direction to display image signals as the total of 36n parallaxes
at a stereoscopic image display time, and by an effective pixel
with a generally square shape comprising 3 pixels of red, green and
blue arranged laterally, ignoring a lateral positional deviation by
1/6 an effective pixel width and regarding the effective pixel as a
square arrangement to display image signals at a flat image display
time where the beam controlling element has been detached or a
function thereof has been invalidated are performed.
33. A display method using a stereoscopic display device according
to claim 17, the display method comprising: by an effective pixel
with a generally square shape comprising 3n.times.9n (n=1, 2, 3, .
. . ) pixels arranged in a vertical direction and in a horizontal
direction, applying the same parallax image information to 3n
pixels arranged in a straight line in the same vertical direction
as an extending direction of the opening portion of the beam
controlling element and in the same position in a horizontal
direction to display image signals as the total of 9n parallaxes at
a stereoscopic image display time, and by an effective pixel with a
generally square shape comprising 3 pixels of red, green and blue
arranged laterally, displaying image signals at a flat image
display time where the beam controlling element has been detached
or a function thereof has been invalidated are performed.
34. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No.
2003-315356, filed on Sep. 8, 2003 in Japan, the entire contents of
which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a stereoscopic display
device and a display method.
[0004] 2. Related Art
[0005] As a stereoscopic image or motion picture display device
allowing display of a motion picture, so-called "a
three-dimensional display", ones of various systems have been
known. In recent years, particularly, a demand for a display device
of a flat panel type employing a system where dedicated eyeglasses
or the like are not used is increasing. As a stereoscopic motion
picture display device of such a type, there is known one using a
principle of holography, which is difficult to be put in a
practical use. A system where a beam controlling element is
installed just in front of a display panel (a display device) whose
pixel positions are fixed, such as a liquid crystal display device
of a direct view type or a projection type or a plasma display
device is known as a system which can be realized relatively
easily. In this connection, the beam controlling element serves to
control beams from the display panel to direct them to an
observer.
[0006] The beam controlling element is generally called "a parallax
barrier", and it controls beams such that different images are seen
according to an angle change even at one or the same position on
the beam control element. Specifically, when only a left and right
parallax (horizontal disparity) is applied, a slit or a lenticular
sheet (a cylindrical lens array) is used, and when a vertical
disparity is also included, a pinhole array or a lens array is
used. The systems using the parallax barrier are also classified to
a binocular system, a multiview system, an ultra-multiview system,
an integral photography (hereinafter, also called "IP") system. A
basic principle common to these types is substantially the same as
that used in a stereoscopic photograph invented about a hundred
years ago.
[0007] In general, it is considered that a difference between the
IP system and an LS (lenticular sheet) system is based upon whether
pixels are present on an image plane or on a focal plane. In an
actual design, particularly, in a case that there are many pixels,
however, the difference between the image plane and the focal plane
is in a range of 0.1 mm or less, even if there is no aberration,
which not only makes it difficult to make a discrimination
therebetween regarding precision but also makes it difficult to
make a discrimination between presence and absence of beam
converging at a viewing distance. The IP system described in this
text means such a constitution that discrimination between
positions of an image plane and a focal plane is not made but a
position of a lateral viewpoint where a normal stereoscopic image
can be seen at the viewing distance is arbitrary or continuous.
Further, the multiview system described in this text is not
equivalent to the LS system but it means such a constitution that a
position of a lateral viewpoint where a normal stereoscopic image
can be seen at the viewing distance is determined on the basis of
an interpupilliary distance.
[0008] In both the IP system and the multiview system, since the
viewing distance is usually finite, a display image is produced
such that a perspective projection image at the viewing distance
can be actually seen.
[0009] In the IP system, since a parallax barrier pitch Ps when
viewed at a position of the eyes of an observer is not integer
times a pixel-to-pixel pitch Pp, moire may be viewed when a black
matrix is not ignored. In particular, when a slit or a lenticular
sheet with a low aperture ratio of pixels in a horizontal direction
is used, moire is easily seen. Even in the multiview system where
the parallax barrier pitch Ps which can see at the viewing distance
is integer times the pixel-to-pixel pitch Pp, when deviation occurs
in a forward or rearward direction regarding the viewing distance,
moire can see on a similar principle. However, it is known that,
when the aperture ratio of pixels in a horizontal direction is 50%
and the pixels have a delta arrangement, the moire can be cancelled
and moire can be cancelled even in another pixel shape (for
example, refer to Japanese Patent Laid-Open No. 7-15752). It is
also known that moire is cancelled by inclining a lenticular sheet
by an angle of about 9.5.degree. (for example, refer to Japanese
Patent Laid-Open No. 2001-501073). It is made possible to allocate
parallaxes in a vertical direction, namely in two or more lines in
a distributing manner by utilizing the delta arrangement or the
lenticular sheet disposed obliquely, and such an advantage can also
be obtained that the number of parallaxes is increased by reducing
a difference in resolution between a vertical direction and a
horizontal direction. Besides, it is known that moire or color
moire can be reduced by using a diffusion film or defocusing (for
example, refer to Japanese Patent Laid-Open No. 8-149520).
[0010] When a stereoscopic image is displayed, since original image
data such as video images obtained by a plurality of cameras has a
pixel arrangement constituted of a square arrangement like image
data for an ordinary flat display and a shape of each pixel is
square, it is desirable for conversion to a stereoscopic image
conducted by fast image processing that effective pixels
constitutes a square arrangement and each pixel itself is square
even on a side of the stereoscopic display device. In the
stereoscopic display device, in order to cause resolutions in a
horizontal direction and in a vertical direction to match with each
other, namely, in order to set an aspect ratio of effective pixels
to 1, it is necessary to set the number of parallax to a multiple
of 3, when a color filter has a stripe arrangement. However, when
the number of parallaxes is set in this manner, there occurs a
problem that color moire appears because a period of color of a
color filter and a period of the parallax barrier along a
horizontal direction are close to each other. As means for solving
such a problem, there is proposed a method for shifting the number
of parallaxes from the multiple of 3, but the aspect ratio of the
effective pixel deviates from 1 in the method, which results in
need for converting an image. As another solution, there has been
proposed a method for applying a mosaic arrangement to a color
filter.
[0011] Further, a system which allows switching of a stereoscopic
display device between a stereoscopic display mode and a flat
display mode has been disclosed. In such a disclosure, there have
been known a method for performing switching of liquid crystal
elements constituting a parallax barrier, a method for switching
distances from a display plane of a lenticular sheet, a method of
utilizing a liquid crystal lens, or the like.
[0012] As described above, in the conventional stereoscopic display
devices, means for canceling moire have been disclosed in the above
publications. However, it is a difficult problem that a aspect
ratio of pixels is 1 and the pixels constitute a square arrangement
for suppressing moire or color moire and attaining matching with a
fast image processing, color data or information for each parallax
is prevented from lacking, or a deviation in color distribution is
canceled.
[0013] In the conventional stereoscopic display devices, there is
still a problem that, when switching is performed between a flat
image (two-dimensional) display and a stereoscopic image
(three-dimensional) display, a resolution varies largely and an
image quality at a time of flat display lowers due to deviation of
a color distribution or the like.
SUMMARY OF THE INVENTION
[0014] The present invention has been made in view of these
circumstances, and an object thereof is to a stereoscopic display
device where, while suppressing moire or color moire, an aspect
ratio of a pixel is set to 1 and simultaneously pixels constitute a
square arrangement, and a resolution or an image quality is not
changed largely even when switching is performed between a flat
image display and a stereoscopic image display.
[0015] A stereoscopic display device according to a first aspect of
the present invention includes: a display device having pixels
developing either one color of red, green and blue which are
disposed within a display plane; and a beam controlling element
which is disposed at the front of the display device and has a
plurality of apertures or a plurality of lenses having an optical
opening portion extending linearly in vertical direction,
controlling beam directions from the pixels to divide the display
plane of the display device into elemental images corresponding to
the respective apertures or lenses of the beam controlling element,
wherein a vertical period of pixel rows comprising the pixels
arranged in one row in a lateral direction is three times a lateral
period of the pixels, the pixels developing red, green and blue are
alternately arranged in a lateral direction in the same row, the
pixels in one row of two rows adjacent in a vertical direction are
arranged such that lateral positions thereof are shifted to the
pixels in the other row by 1/2 of the lateral period of the pixels,
the pixels in rows adjacent in the same column through one row
interposed therebetween are the pixels developing different colors
of red, green and blue; and a pitch of the elemental images is
equal to a width of 18n (n=1, 2, 3 . . . ) pieces of the pixels,
and a lateral pitch of the beam control element is smaller than the
width of the 18n pieces of the pixels.
[0016] A stereoscopic display device according to a second aspect
of the present invention includes: a display device having pixels
developing either one color of red, green and blue which are
disposed within a display plane; and a beam controlling element
which is disposed at the front of the display device and has a
plurality of apertures or a plurality of lenses having an optical
opening portion extending linearly in vertical direction,
controlling beam directions from the pixels to divide the display
plane of the display device into elemental images corresponding to
the respective apertures or lenses of the beam controlling element,
wherein a vertical period of pixel rows comprising the pixels
arranged in one row in a lateral direction is three times a lateral
period of the pixels, the pixels developing red, green and blue are
alternately arranged in a lateral direction in the same row, the
pixels in one row of two rows adjacent in a vertical direction are
arranged such that lateral positions thereof are shifted to the
pixels in the other row by 1/2 of the lateral period of the pixels,
the pixels in rows adjacent in the same column through one row
interposed therebetween are the pixels developing different colors
of red, green and blue, and an average value of pitches of the
elemental images is larger than a width of 18n (n=1, 2, 3 . . . )
pieces of the pixels, and a lateral pitch of the beam controlling
element is equal to a width of 18n pieces of the pixels.
[0017] A stereoscopic display device according to a third aspect of
the present invention includes: a display device having pixels
developing either one color of red, green and blue which are
disposed within a display plane; a beam controlling element which
is disposed at the front of the display device and has a plurality
of apertures or a plurality of lenses having an optical opening
portion extending linearly in vertical direction, controlling beam
directions from the pixels to divide the display plane of the
display device into elemental images corresponding to the
respective apertures or lenses of the beam controlling element; and
a diffusion layer having a haze of 20 or more to 70 or less, which
is arranged between a pixel plane of the display device and the
beam controlling element, wherein a vertical period of pixel rows
comprising the pixels arranged in one row in a lateral direction is
three times a lateral period of the pixels, the pixels developing
red, green and blue are alternately arranged in a lateral direction
in the same row, the pixels developing red, green and blue are
alternately arranged in a vertical direction in the same column,
and a pitch of the elemental images is equal to a width of 9n (n=1,
2, 3 . . . ) pieces of the pixels, and a lateral pitch of the beam
control element is smaller than the width of the 9n pieces of the
pixels.
[0018] A stereoscopic display device according to a fourth aspect
of the present invention includes: a display device having pixels
developing either one color of red, green and blue which are
disposed within a display plane; a beam controlling element which
is disposed at the front of the display device and has a plurality
of apertures or a plurality of lenses having an optical opening
portion extending linearly in vertical direction, controlling beam
directions from the pixels to divide the display plane of the
display device into elemental images corresponding to the
respective apertures or lenses of the beam controlling element; and
a diffusion layer having a haze of 20 or more to 70 or less, which
is arranged between a pixel plane of the display device and the
beam controlling element, wherein a vertical period of pixel rows
comprising the pixels arranged in one row in a lateral direction is
three times a lateral period of the pixels, the pixels developing
red, green and blue are alternately arranged in a lateral direction
in the same row, the pixels developing red, green and blue are
alternately arranged in a vertical direction in the same column,
and an average value of pitches of the elemental images is larger
than a width of 9n (n=1, 2, 3 . . . ) pieces of the pixels, and a
lateral pitch of the beam controlling element is equal to a width
of 9n pieces of the pixels.
[0019] A display method using a stereoscopic display device of the
first aspect of the present invention, the display method includes:
by an effective pixel with a generally square shape comprising
6n.times.18n (n=1, 2, 3, . . . ) pixels arranged in a vertical
direction and in a horizontal direction, applying the same parallax
image information to 3n pixels arranged in a straight line in the
same vertical direction as an extending direction of the opening
portion of he beam controlling element and in the same position in
a horizontal direction to display image signals as the total of 36n
parallaxes at a stereoscopic image display time, and by an
effective pixel with a generally square shape comprising 3 pixels
of red, green and blue arranged laterally, ignoring a lateral
positional deviation by 1/6 an effective pixel width and regarding
the effective pixel as a square arrangement to display image
signals at a flat image display time where the beam controlling
element has been detached or a function thereof has been
invalidated are performed.
[0020] A display method using a stereoscopic display device of the
second aspect of the present invention, the display method
includes: by an effective pixel with a square shape comprising
3n.times.9n (n=1, 2, 3, . . . ) pixels arranged in a vertical
direction and in a horizontal direction, applying the same parallax
image information to 3n pixels arranged in a straight line in the
same vertical direction as an extending direction of the opening
portion of he beam controlling element and in the same position in
a horizontal direction to display image signals as the total of 9n
parallaxes at a stereoscopic image display time, and by an
effective pixel with a square shape comprising 3 pixels of red,
green and blue arranged laterally, displaying image signals at a
flat image display time where the beam controlling element has been
detached or a function thereof has been invalidated are
performed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a perspective view schematically showing a pixel
arrangement to which a first pixel arrangement example of a
stereoscopic display device according to a first embodiment of the
present invention is applied;
[0022] FIG. 2 is a perspective view schematically showing a pixel
arrangement to which a second pixel arrangement example of a
stereoscopic display device according to the first embodiment of
the present invention is applied;
[0023] FIG. 3 is a perspective view schematically showing a pixel
arrangement to which a pixel arranging method of a first
comparative example to the first embodiment is applied;
[0024] FIG. 4 is a perspective view schematically showing a pixel
arrangement to which a pixel arranging method of a second
comparative example to the first embodiment is applied;
[0025] FIG. 5 is a plan view schematically showing a pixel
arrangement on a display plane of the stereoscopic display device
according to the first embodiment of the present invention is
applied;
[0026] FIG. 6 is a plan view schematically showing another pixel
arrangement on a display plane of the stereoscopic display device
according to the first embodiment of the present invention is
applied;
[0027] FIGS. 7A and 7B are views schematically showing examples of
linear shapes at flat display times of the first and second image
arrangement examples of the first embodiment of the present
invention, and FIG. 7C is a view schematically showing an example
of a linear shape at a flat display time of a comparative
example;
[0028] FIG. 8A is a perspective view of a case that a beam
controlling element is a lenticular sheet in the first embodiment,
and FIG. 8B is a perspective view of a case that the beam
controlling element is a slit in the first embodiment;
[0029] FIG. 9 is a perspective view schematically showing the
stereoscopic display device according to the first embodiment of
the present invention;
[0030] FIG. 10(a) is a front view of a liquid crystal panel and a
parallax barrier according the first embodiment;
[0031] FIG. 10(b) is a plan view showing an image arrangement of
the stereoscopic display device according to the first
embodiment;
[0032] FIG. 10(c) is a side view showing the image arrangement of
the stereoscopic display device according to the first
embodiment;
[0033] FIG. 11 is an illustrative diagram showing a positional
relationship among pixels in an integral photography system, an
elemental image and a parallax barrier;
[0034] FIG. 12 is an illustrative diagram showing a positional
relationship among pixels in an integral photography system, an
elemental image and a parallax barrier according to the first
embodiment of the present invention;
[0035] FIG. 13 is an illustrative diagram showing an image
arranging method of a stereoscopic display device of an integral
photography system according to the first embodiment of the present
invention;
[0036] FIG. 14 is an illustrative diagram showing a positional
relationship among pixels, an elemental image and a parallax
barrier of a multiview system;
[0037] FIG. 15 is an illustrative diagram showing an image
arranging method of a stereoscopic display device of the multiview
system according to the first embodiment of the present
invention;
[0038] FIG. 16 is an illustrative diagram showing an image
composing method of the stereoscopic display device according to
the first embodiment of the present invention;
[0039] FIG. 17 is a table showing one example of a parallax image
allocation of the stereoscopic display device according to the
first embodiment of the present invention;
[0040] FIG. 18 is a flowchart showing a switching processing
between a stereoscopic display and a flat display in the first
embodiment of the present invention;
[0041] FIG. 19 is an illustrative diagram showing a positional
relationship between pixels and an elemental image boundary in the
first embodiment of the present invention;
[0042] FIG. 20 is a perspective view schematically showing a pixel
arrangement to which a pixel arrangement on the stereoscopic
display device according to the first embodiment of the present
invention is applied;
[0043] FIG. 21 is a perspective view schematically showing a pixel
arrangement to which a pixel arrangement on a stereoscopic display
device according to a second embodiment of the present invention is
applied;
[0044] FIG. 22 is a plan view schematically showing a pixel
arrangement to which a pixel arrangement on a display plane of the
stereoscopic display device according .sub.to .sub.the second
embodiment of the present invention is applied;
[0045] FIG. 23 is an illustrative diagram showing a positional
relationship among pixels in an integral photography system, an
elemental image and a parallax barrier;
[0046] FIG. 24 is an illustrative diagram showing a positional
relationship among pixels in an integral photography system, an
elemental image and a parallax barrier according to the second
embodiment of the present invention;
[0047] FIG. 25 is an illustrative diagram showing an image
arranging method of a stereoscopic display device of an integral
photography system according to the second embodiment of the
present invention;
[0048] FIG. 26 is an illustrative diagram showing a positional
relationship among pixels, an elemental image and a parallax
barrier of a multiview system;
[0049] FIG. 27 is an illustrative diagram showing an image
arranging method of a stereoscopic display device of the multiview
system according to the second embodiment of the present
invention;
[0050] FIG. 28 is a table showing one example of a parallax image
allocation of the stereoscopic display device according to the
second embodiment of the present invention;
[0051] FIG. 29 is a flowchart showing a switching processing
between a stereoscopic display and a flat display in the second
embodiment of the present invention;
[0052] FIG. 30 is a table for characteristic comparison of
stereoscopic display devices according to one embodiment of the
present invention and a comparative example;
[0053] FIG. 31A is a table showing one example of a pixel number
allocation when a color filter arrangement is delta/mosaic delta,
and FIG. 31B is a table showing one example of a pixel number
allocation when a color filter arrangement is mosaic;
[0054] FIGS. 32A to 32C are diagrams schematically showing a
display method on an excess row region and an excess column region
of a stereoscopic display device according to one embodiment of the
present invention;
[0055] FIG. 33 is a diagram schematically showing signal polarities
of respective pixels within the same field of a stereoscopic
display device according to one embodiment of the present
invention;
[0056] FIG. 34 is a diagram schematically showing signal polarities
of respective pixels within the same field of a stereoscopic
display device according to one embodiment of the present
invention;
[0057] FIG. 35 is a diagram schematically showing signal polarities
of respective pixels within the same field of a stereoscopic
display device according to one embodiment of the present
invention;
[0058] FIG. 36 is a diagram schematically showing signal polarities
of respective pixels within the same field of a stereoscopic
display device according to one embodiment of the present
invention; and
[0059] FIG. 37 is a diagram schematically showing signal polarities
of respective pixels within the same field of a stereoscopic
display device according to one embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0060] A stereoscopic display device according to embodiments of
the present invention will be explained below with reference to the
drawings.
First Embodiment
[0061] FIG. 1 is a perspective view schematically showing a
constitution of a stereoscopic display device according to a first
embodiment of the present invention.
[0062] In such a stereoscopic display device as shown in FIG. 1, a
lenticular sheet 334 constituted of cylindrical lenses having an
optical aperture extending in a vertical direction is arranged as a
beam controlling element at the front of a display plane of a flat
parallax image display portion such as a liquid crystal panel.
Since the optical aperture is neither oblique nor stepwise but it
constitutes a straight line in a vertical direction, a pixel
arrangement at a stereoscopic display time can easily be set to a
square arrangement. Pixels 34 with an aspect ratio of 3:1 are
arranged straightly in one line manner, and the respective pixels
34 are arranged such that red (R), green (G) and blue (B) are
alternately positioned laterally in the same line on the display
face. FIG. 5 and FIG. 6 are plan views showing examples of a pixel
arrangement. In FIG. 5 and FIG. 6, numerals of -18 to 18 represent
parallax numbers, and neighboring parallax numbers are allocated to
neighboring rows. A vertical period of a pixel row is three times a
lateral period Pp of pixels 34, and pixels 34 adjacent in a
vertical direction are arranged such the lateral positions of the
pixels 34 are arranged so as to be shifted by 1/2 of the lateral
period of the pixels 34. Some of pixels 34 in adjacent or
neighboring rows include adjacent pixels with the same color, but
pixels 34 in rows adjacent to each other through one row interposed
therebetween in the same column are pixels developing different
colors.
[0063] Each pixel 34 has an opening portion or a light emitting
portion at a fixed area ratio, and the opening portion is
surrounded by black matrixes 35. Thus, arrangement of pixels is
shifted between the adjacent rows, and the columns are formed in a
zigzag manner. Accordingly, moire or color moire is canceled on the
whole display area so that an image can be displayed.
[0064] A width of the opening portion in a horizontal direction is
preferable to be equal to a width of a light shielding portion in a
horizontal direction. However, when defocus or aberration of a
lens, or a diffusion film attached to a polarizing plate (which is
a constituent element for a liquid crystal panel) or the like
between the display face and the lenticular sheet is present, the
width of the opening portion in the horizontal direction is
designed so not as to cause moire in view of these conditions.
[0065] Incidentally, in a color image display device which displays
a color image, three pixels 34 of R, G and B constitute one
effective pixel, namely, a minimum unit where luminance and color
can be set arbitrarily. In general, each of R, G and B is
frequently called "sub-pixel". In this text, a concept including
the sub-pixel and pixel generally called will be explained
hereinafter as a pixel 34.
[0066] Referring to FIG. 1 again, on the display plane shown in
FIG. 1, one effective pixel 43 (one effective pixel is indicated
with a black frame in FIG. 1) is constituted of pixels 34
comprising 18 columns and 6 rows. Since horizontal positions of
pixels in a set of two adjacent rows are shifted from each other, a
group of pixels at different 36 horizontal positions are present in
the two rows, and three pixels arranged vertically on every other
line for each horizontal position are present in the effective
pixel 43. In such a display portion structure, a stereoscopic
display which gives 36 parallaxes in a horizontal direction is made
possible. Incidentally, when parallax is applied in a vertical
direction too, such a constitution can be employed that a boundary
of the effective pixel 43 in a horizontal direction is regarded as
an elemental image boundary in a vertical direction, two parallaxes
are allocated in the vertical direction, and the total of 72
parallaxes are applied by multiplying the parallaxes in the
vertical direction by those in the horizontal direction.
[0067] FIG. 1 illustrates a portion near a central portion on the
entire display plane, where a beam controlling element is
positioned so as to generally face the front of the elemental image
(the effective pixel 43).
[0068] In this display structure, a stereoscopic display with 36
parallaxes in a horizontal direction can be made possible. In the
multiview system, there are 36 views, a elemental image pitch is a
pitch of 18 pixels, or a 18-pixels pitch, and a lateral pitch of
the beam controlling element becomes smaller than the 18-pixels
pitch.
[0069] In the IP (integral photography) system, for example, when
such a design is employed that the 18-pixels pitch is equal to the
parallax barrier pitch Ps so that a set of parallel beams can be
formed, the elemental image boundary occurs at a slightly larger
interval (for example, 18.02) than a width of 18 pixels, or a
18-pixels width, so that the width of the effective pixel
eventually corresponds to a width of 36 columns or a width of 37
columns depending on its position in the display face. That is, an
average value of the elemental image pitches is larger than the
width of 18 pixels and the lateral pitch of the beam controlling
element 334 is the width of 18 pitches. Since the effective pixel
43 has an aspect ratio of 1 and it constitutes a square
arrangement, displaying in a vertical direction can be conducted
with substantially the same effective resolution as the horizontal
direction. Therefore, production of a display image is made easy,
and display data or information to be applied to each pixel can be
obtained relatively fast. The resolution in the vertical direction
is not required to match with that in the horizontal direction, the
maximum resolution depends on a pixel row pitch, and displaying
with substantially a higher resolution than that in the horizontal
direction can be made. In such displaying, a resolution which an
observer feels actually becomes higher than the effective
horizontal resolution.
[0070] FIG. 18 is a flowchart showing a switching process between a
stereoscopic display mode and a flat display mode. At a
stereoscopic image display time, equal parallax image data or
information is applied to three pixels arranged in a vertical
direction in a straight line similar to a direction in which the
opening portion of the beam controlling element extends and at the
same position in a lateral direction by an effective pixel with a
generally square shape comprising pixels of vertical 6
pieces.times.horizontal 18 pieces within the range of the effective
pixel 43, so that image signals are applied as the total of 36
parallaxes and displaying is performed. At a flat image display
time where the beam controlling element is detached or its function
is invalidated, a lateral positional deviation of 1/6 effective
pixel width for each row is ignored and the effective pixel is
regarded as a square arrangement, so that image signals is applied
to perform displaying by an effective pixel with a generally square
shape comprising three pixels of red, green and blue arranged
horizontally.
[0071] Thus, it is also made possible to change the resolution
depending on display mode. As the switching method, there is a
method where a selection signal is transmitted to a parallax image
processing section by a manual switch or an automatic detection
interlocked with attaching operation/detaching operation of the
lenticular sheet. The parallax image processing section can be
disposed in an image processing apparatus separated from a
stereoscopic display device main body.
[0072] In the multiview system, for example, 36 views system, the
elemental image pitch Pe is equal to a 18-pixel-to-pixel pitch Pp,
but it is not generally an integer times the 18-pixel-to-pixel
pitch Pp in the IP system. In the IP system, the parallax barrier
pitch Ps is 18 times the 18-pixel-to-pixel pitch and the number of
parallax reaches 36, the elemental image pitch Pe take a value (for
example, 18.02) slightly larger than the 18-pixel-to-pixel pitch.
Accordingly, strictly speaking, the resolution in the horizontal
direction is slightly different from that in the vertical
direction, but there occurs almost no problem even if both of them
are practically handled as the same values.
[0073] In a display plane example shown in FIG. 2, such a
constitution is employed that pixels 34 with same color are formed
obliquely in a straight line, which is different from the example
shown in FIG. 1. Even in this case, an object of the present
invention is approximately achieved but the example shown in FIG. 1
is further preferable in view of a color distribution between
parallax images at a stereoscopic display time or an image quality
at a switching time to the flat displaying. At the switching time
to the flat displaying, a lateral straight line display does not
cause any problem in both the examples shown in FIG. 1 and FIG. 2,
but a vertical straight line display causes such a difference as
shown in FIGS. 7A and 7B. In the constitution shown in FIG. 2
corresponding to FIG. 7B, such a problem occurs that the vertical
straight line display appears as an oblique line with steps. In
FIGS. 7A, 7B and 7C, a letter "W" denotes white, "R" denotes red,
"G" denotes green, and "B" denotes blue.
[0074] A display plane example shown in FIG. 3 is a comparative
example, where an aspect ratio of the pixel 34 is 3:4. This example
has a pixel shape and a pixel arrangement called "a delta
arrangement", but constitution is made for a parallax image
(constituted of three pixels arranged vertically on every other
line) at a stereoscopic display time to even color components such
that pixels with the same color do not form a straight line
obliquely. In this case, when the elemental image pitch or the
parallax barrier pitch is a multiple of a pitch of 4.5 pixels, such
conditions as a square pixel, a square arrangement, a color
distribution, a horizontal parallax vertical allocation and the
like can be satisfied. In the display plane shown in FIG. 3,
however, since coarseness of a straight line in both vertical and
horizontal directions is conspicuous especially at the time of
switching to the flat image display, as shown in FIG. 7C, this
display plane is not suitable for a high fineness information
display and it does not meet an object of the present
invention.
[0075] A display plane example shown in FIG. 4 is a comparative
example, where the elemental image pitch Pe or the parallax barrier
pitch Ps is 9 times the pixel pitch Pp and the number of parallaxes
is 18. In this case, when the effective pixel is formed in a square
shape, as indicated by reference numeral 43, a color component and
the number of pixels between parallax images appear as 2 or 1
alternately. Therefore, in order to eliminate lack in color
component, a vertical size of the effective pixel must be increased
to two times in a vertical direction, which does not match with the
object of the present invention. Such a case that Pe or Ps is not a
multiple of 18 but a multiple of 9 (for example, 27) is similar to
the above.
[0076] A display plane example shown in FIG. 6 is an example where
a shape of the opening portion has been changed without changing
the center position of a pixel, as compared with the example shown
in FIG. 5. A constitution of slightly changing the shape of an
opening portion within a range where the center (the center of
gravity) position of a pixel is not changed is not contrary to the
spirit of the present invention. Similarly, a constitution of
slightly changing the shape of the optical aperture of the beam
controlling element too in a range where a relative position of the
center (the center of gravity) to each pixel is not changed is not
contrary to the spirit of the present invention.
[0077] A comparison table including the above embodiments and
comparative examples and collectively describing differences in
characteristics due to the number of parallaxes (per row), a color
arrangement and an opening direction of the beam controlling
element is shown in FIG. 30. In the table, "n" denotes any natural
number. Here, only combinations where no moire occurs are listed.
The delta arrangement is limited to an aspect ratio of 3:1 in view
of the image quality at the flat image display time such as
described in explanation for FIG. 3. The term "mosaic-delta" means
a constitution including a delta arrangement and pixels with
different colors adjacent to each other through one row interposed
therebetween (constituting a mosaic arrangement as viewed with
every other row), and all of the color arrangements shown in FIG. 1
to FIG. 6 correspond to this mosaic-delta. A simple delta
arrangement which is not the mosaic-delta has a constitution that
pixels adjacent to each other through one row interposed
therebetween in vertical direction have the same color, as well
known. In the table shown in FIG. 30, ".largecircle." indicates
excellent characteristics, ".DELTA." indicates insufficient
characteristics, and ".times." indicates poor characteristics. The
number of parallax per row corresponds to Ps/Pp in case of the IP
having sets of parallel beams and it corresponds to Pe/Pp in case
of the multiview system. According to this comparison table,
assuming that moire does not occur, the number of combinations
where all of square pixel/square arrangement suitable for a fast
image processing and color distributions influencing an image
quality are excellent is limited.
[0078] In the examples referring to FIG. 1, FIG. 5 and FIG. 6, a
beam controlling element 334 having an elemental image 43 or the
parallax barrier pitch of 18n times the pixel pitch and an optical
aperture extending in a vertical direction is provided and pixels
with an aspect ratio of 3:1 are arranged in a delta shape where
pixels 34 in rows adjacent to each other through a row interposed
therebetween develop different colors (mosaic delta) and identical
colors do not form a continuous straight line. With such a
constitution, even in either of a stereoscopic display and a flat
display, an aspect ratio of effective pixels becomes 1 and the
effective pixels constitute a square arrangement, so that a fast
image processing is made possible easily. The comparison table
shown in FIG. 30 shows such a fact that this constitution is one of
the most preferable constitutions.
[0079] In order to suppress flicker or cross talk in a liquid
crystal display device, a polarity reversing drive for each field
is frequently performed. However, when a color arrangement is
different from an ordinary one like this embodiment, particularly
when displaying is performed with a single color at the flat
display time where the beam controlling element is invalidated,
color flicker may occur. At a stereoscopic display time, since a
set of pixel rows which can be seen varies according to a position
of a viewpoint, flicker occurs partially in some case, even if a
simple signal line inversion drive (a V line inversion drive) or
the like is conducted. In order to prevent occurrence of flicker,
it is desirable that pixels with the same color closest to each
other in adjacent rows are driven in the same field by image
signals with different polarities, or pixels closest to each other
in the same column are driven in the same field by image signals
with different polarities, and it is further desirable that both
the operations are performed. That is, such a disposition that an
oblique direction along which colors are arranged and another
oblique direction along which the same polarities are arranged are
crossed is suitable. As examples showing an arrangement of signal
polarities in the same field, there are such patterns as shown in
FIG. 33 to FIG. 35.
[0080] Next, stereoscopic displays performed by parallax image
arrangements of the multiview system and the IP system will be
explained with reference to FIG. 8A to FIG. 17. Displays of
stereoscopic images shown in FIG. 8A to FIG. 16 are realized by the
display devices explained with reference to FIG. 1 to FIG. 7.
[0081] In not only the IP system but also the multiview system,
since the viewing distance is generally finite, a display image is
produced such that a perspective projection image at the viewing
distance can be seen actually. Image processing (rendering process
in a computer graphics) is performed for each crossing point of a
line connecting a pixel and a slit and a horizontal line on a
viewing distance plane (a position corresponding to a viewpoint
height) so that a perspective projection image is produced. Here,
the perspective projection image may be produced for each of a pair
of a crossing point (viewpoint) of a pixel column substituted for
the pixel and the pixel.
[0082] FIG. 8A is a perspective view of a lenticular sheet 334
serving as a beam controlling element or a parallax barrier, and
FIG. 8B is a perspective view of a slit 333 serving as a beam
controlling element or a parallax barrier.
[0083] FIG. 9 is a perspective view schematically showing the whole
of a stereoscopic display device. In a stereoscopic display device
shown in FIG. 9, a diffusion sheet 301 is provided between an
independent parallax barrier 332 and a flat image display portion
331, but it is not required necessarily. When the flat image
display portion 331 is constituted of a liquid crystal display
device, a diffusion layer on a surface of a polarizing plate may be
substituted for the diffusion sheet, and when a lenticular sheet is
used in place of the parallax barrier 332, a back face thereof may
has a diffusion property.
[0084] FIGS. 10(a), 10(b) and 10(c) are developments schematically
showing beam loci within a vertical plane and a horizontal plane on
the basis of a display portion of the stereoscopic display device
shown in FIG. 9, FIG. 10(a) being a front view of the flat image
display portion 331 and the parallax barrier 332, FIG. 10(b) being
a plan view showing an image arrangement of the stereoscopic
display device and FIG. 10(c) being a side view showing the
stereoscopic display device. As shown in FIG. 9 and FIGS. 10(a) to
10(c), the stereoscopic display device is provided with the flat
image display portion 331 such as a liquid crystal display device
and the parallax barrier 332 having optical apertures. The parallax
barrier 332 is constituted of a lenticular sheet 334 of a shape
where optical apertures extending in a straight line manner
vertically are arranged periodically in a horizontal direction or
slits 333, such as shown in FIGS. 8A and 8B. In the stereoscopic
display device, a stereoscopic image can be observed at the front
and the rear of the flat image display portion 331 by observing a
display device 331 via the parallax barrier 332 from the position
of eyes. Here, the number of pixels on the flat image display
portion 331 is 1920 in the lateral direction (the horizontal
direction) and 1200 the longitudinal direction (the vertical
direction), when the number is counted on the basis of a pixel
group constituting the minimum unit for a square, and a pixel group
of each minimum unit includes pixels of red (R), green (G) and blue
(B).
[0085] FIG. 11 or FIG. 12 is a diagram schematically showing a
horizontal section of a display portion of the stereoscopic display
device. A pitch Ps (period) of a slit 333 or the lenticular sheet
334 in a horizontal direction as shown here is set to a size of an
integer number of pixels correctly. That is, a center axis 351
(refer to FIG. 11) passing through the center between respective
slits 333 or a reference axis 353 (refer to FIG. 12) passing
through a boundary between adjacent lenticular lenses of the
lenticualr sheet 334 passes through an middle between the center of
a pixel on an odd row (a pixel shown with solid lines in the
figure) and the center of a pixel on an even row (a pixel shown
with broken lines in the figure). An integer number of pixels are
arranged in region corresponding to a space between the center axes
351 or the reference axes 352, and a pitch Ps (period) of the
center axes 351 or the reference axes 352 in a horizontal direction
is set to a constant value.
[0086] FIG. 13 is a diagram schematically showing a front of the
display portion of the stereoscopic device. In an example shown
here, the pitch Ps in the horizontal direction is set to a size of
18 pixels. A gap d (refer to FIG. 10(b)) between the flat image
display portion 331 and the parallax barrier 332 of the display
device is effectively set to about 2 mm considering the refractive
index of glass substrate or lens material. Thus, such a
constitution that the pitch Ps of the parallax barrier 332 (not the
pitch Ps which can be seen due to a difference in distance but an
actual pitch Ps of the parallax barrier) is integer times the
pixel-to-pixel pitch Pp is generally not classified to the
multiview system, but it is classified to the one-dimensional
integral photography, as explained above, where such an advantage
that a stereoscopic image producing efficiency is improved is
obtained, because the set of parallel beams are produced. On the
other hand, such a constitution that the elemental image pitch Pe
is integer times the pixel-to-pixel pitch Pp like the horizontal
section shown in FIG. 14 is generally classified to the multiview
system.
[0087] In FIGS. 10(a), 10(b) and 10(c), when a viewing distance L
between the parallax barrier 332 and the a viewing distance plane
343, the parallax barrier pitch Ps, and the parallax barrier gap d
are defined, the pitch Pe of the elemental image is determined on
the basis of a distance or interval obtained when an aperture
center is projected on a display element from a viewpoint on the
viewing distance plane 343. Reference numeral 346 denotes a line
connecting the viewpoint position and each aperture center, and a
viewing region width W is determined from such a condition that
elemental images do not overlap with each other on the display
plane of the display device.
[0088] In the one-dimensional IP system, it should be noted that
the straight line 346 does not pass through the center of each
pixel on the display plane of the display device necessarily. On
the other hand, in the multiview system, a line connecting the
viewpoint position and each aperture center passes through a pixel
center to coincide with a beam locus. When the horizontal pitch Ps
of the aperture is integer times the pixel pitch Pp, the pitch Pe
of the elemental image includes a fraction slightly shifted on the
large side from the integer times of the pixel pitch Pp. Even when
the horizontal pitch Ps of the aperture is not the integer times
the pixel pitch Pp, eventually, the pitch Pe of the elemental image
generally includes a fraction shifted from the integer times the
pixel pitch Pp in the one-dimensional IP system. On the other hand,
the pitch Pe of the elemental image becomes integer times the pixel
pitch Pp in the multiview system.
[0089] FIG. 13 and FIG. 15 are conceptual diagrams of arrangement
methods of images on display planes of the display devices in the
IP system and the multiview system, obtained when a display portion
of a stereoscopic display device has been viewed from the front
thereof. The display plane of the display device is divided to
elemental images 370 corresponding to respective apertures (opening
portions of a parallax barrier), and each elemental image 370 is
constituted of pixel columns (columns constituted of a set of
pixels in two adjacent rows because of the delta arrangement)
comprising 36 columns or 37 columns in the IP system (the elemental
image width is originally a fraction slightly larger than 18 times
the pixel width or pixel pitch Pp, but it corresponds to 36 columns
or 37 columns according to a position for digital allocation). The
total number of pixel rows which can be allocated with a parallax
is 11520, because each pixel comprises three sub-pixels and a
positional shift occurs between two rows, the number of apertures
is 320 (in FIG. 13 and FIG. 15, the range of aperture numbers
described in a region shown by reference numeral 364 is a range
indicated by #-160 to #-1, and #1 to #160), and the aperture pitch
Ps is equal to a size of the 18-pixels width.
[0090] In FIG. 13 and FIG. 15, in each pixel column 365,
corresponding parallax numbers (in this example, corresponding to
74 directions of parallax numbers -37 to -1 and 1 to 37) are shown
as items in a region indicated by a reference numeral 363. An
elemental image indicated by aperture number #1 comprises columns
of 36 parallaxes of parallax numbers -18 to -1 and 1 to 18, and an
elemental image indicated by aperture number #-159 comprises
columns of 36 parallaxes of parallax numbers -37 to -2. Since the
width of the elemental image is slightly larger than the width of
the 18-pixels column, when the boundary of the elemental image is
caused to match with the closest pixel row boundary (a normal A-D
conversion), the number of pixel columns in the aperture is 36 in
most apertures, but apertures corresponding to 37 columns occur.
The parallax number range in the aperture is shifted one by one
from the aperture number corresponding to 37 columns. The aperture
numbers corresponding to 37 columns are #5, #13, #21, #30, #38,
#46, #55, #63, #71, #80, #96, #105, #113, #121, #130, #138, #146,
and #155 (and their minus numbers) (in case of the viewing distance
of 700 mm).
[0091] In FIG. 17, aperture numbers (Slit Number in Table)
indicating start and end of arrangement of parallax images in each
direction are shown. In this Table, pixel row numbers at
corresponding 3-D display time, column numbers and pixel column
numbers of the flat display device, and even and odd (odd row: 0
and even row: 1) of the row are also shown.
[0092] Incidentally, unlike the IP system, in the multiview system,
the elemental image widths all comprise a width of 18 pixel
columns, as shown in FIG. 15, and parallax numbers of -18 to -1 and
1 to 18 are similarly arranged in all of the elemental images.
[0093] FIG. 16 is a diagram showing a composing method of a
parallax image and a stereoscopic image in a one-dimensional IP
system under the condition that a set of parallel beams are
provided. An object (subject) to be displayed 421 is projected on a
projection plane 422 at the same position as a plane on which a
beam controlling element of a stereoscopic display device is
actually placed. At this time, projection is performed along
projection lines 425 toward a projection-center line 423 which is
parallel to the projection plane and is positioned at the front (a
central portion in a vertical direction) and within a viewing
distance plane so as to attain vertical perspective
projection/horizontal orthographic projection. The projection lines
do not cross in a horizontal direction but they cross on the
projection-center line in a vertical direction. An image 424 of the
subject which is subjected to vertical perspective
projection/horizontal orthographic projection is formed on the
projection plane by the projecting process. This process is
performed in the same manner as a rasterizing operation or a
rendering operation of a commercially available computer graphics
producing software except that projection processes in a vertical
direction and in a horizontal direction are different from each
other. An image (a parallax image) 426 corresponding to one
direction, which has been subjected to vertical perspective
projection/horizontal orthographic projection on the projection
plane, is divided to respective one columns of pixels along a
vertical direction, and these columns are arranged on a display
plane 427 of the display device in a dividing manner at intervals
of an aperture pitch Ws (at intervals of a fixed number of pixel
columns). Regarding the other projection directions 428, the same
operation as the above is repeated to complete the whole of the
display plane 427. In FIG. 16, only 8 directions of -4, -3, -2, -1,
1, 2, 3 and 4 are shown, but several tens directions will be
required depending on the viewing distance, for example, the number
of projection directions is 74 in the example shown in FIG. 17.
Incidentally, only a column(s) in a required range may be produced
for each projected image 426. The required range is shown in FIG.
17. Respective projecting directions correspond to the parallax
numbers, but respective directions do not have an equal angle but
they are set to have equal intervals on the viewing distance plane
(the projection-center line). That is, this corresponds to an
operation where photographing is performed while parallel movement
(orientation is fixed) of a camera is being conducted at equal
intervals on the projection-center line.
[0094] A Table (delta/mosaic-delta, the number of parallax: 36)
shown in FIG. 31A is a table that, when the elemental image pitch
or the parallax barrier pitch is 18 times the pixel pitch and a
liquid crystal panel having the number of pixels defined by a
normal standard is used for the flat image display portion, excess
rows or columns may occur. Particularly, when the number of pixels
at a stereoscopic display time is caused to match with standard
specification such as VGA, SVGA, XGA or 1/4 thereof, excess may
occur in both row and column. In order to allocate excess rows or
columns to a periphery uniformly, it is preferable that the entire
screen is first made symmetrical to make the number of elemental
images even. It is preferable that an elemental image boundary at a
central position of the whole screen is set such as shown in FIG.
19. That is, in the multiview system, it is desirable that the
elemental image boundary is set at the middle between pixel centers
of pixels in rows adjacent in a vertical direction and the
elemental image boundary is set at a center position 203 of the
flat image display portion 201 in a lateral direction. In the IP
system, it is desirable that an elemental image boundary at the
center position 203 of the display plane in the lateral direction
is set at the middle between pixel centers of pixels in rows
adjacent in a vertical direction. The allocation table shown in
FIG. 17 shows the results obtained by application of this method.
When this method is not applied, not the elemental image boundary
but an elemental image center is disposed at the central portion of
the display plane and the number of excess columns becomes odd,
which results in inconvenience that symmetrical allocation is made
impossible. When allocation of pixels is made symmetrical,
allocation of parallax is made symmetrical, so that an excellent
result can also be obtained regarding a fast image processing.
[0095] FIGS. 32A, 32B and 32C show three examples in total of an
example where an excess pixel row portion 206 is uniformly arranged
above and below the flat image display portion 201 or it is
collectively arranged above or below the flat image display portion
201 and a pattern FIG. 204 serving as a guide for stereoscopic view
is displayed on the excess portion (refer to FIGS. 32A and 32B), an
example where an excess pixel row portion 205 is uniformly arranged
symmetrically and a pattern FIG. 204 serving as a guide for
stereoscopic view is displayed on the excess portion (refer to FIG.
32C) and an example where burr images are displayed on both end
portion (refer to FIG. 32A). In FIGS. 32A, 32B and 32C, reference
numeral 202 denotes a stereoscopic image display portion, and
reference numeral 203 denotes the center line of a display plane of
the flat image display portion 201. As the guide pattern, such a
method can be employed that two lines are displayed on each opening
portion of the beam controlling element such that, when an observer
is present just at a central position of a viewing distance, an
observer can see bright lines with his/her both eyes. Thereby, the
observer himself/herself can confirm whether or not he/she is
present at a proper observing position, which makes stereoscopic
view easy. Regarding both left and right ends, by burring an edge
between an image display portion and a non-display portion, it is
made possible to reduce a factor for blocking a stereoscopic view
such as a frame effect (frame canceling).
Second Embodiment
[0096] FIG. 21 is a perspective view schematically showing a
constitution of a stereoscopic display device according to a second
embodiment of the present invention.
[0097] In such a stereoscopic display device as shown in FIG. 21, a
lenticular sheet 334 comprising cylindrical lenses whose optical
apertures extend vertically, which serves as a beam controlling
element, is disposed at the front of a display plane of a flat
parallax image display portion such as a liquid crystal panel.
Since the optical openings are arranged in a straight line not
stepwise but vertically, it is easy to arrange a pixel arrangement
in a square arrangement at a stereoscopic display time. Pixels 34
with an aspect ratio of 3:1 are arranged laterally and vertically
in a straight manner and in a matrix manner on the display plane,
and respective pixels are arranged such that red, green and blue
are alternately positioned laterally in the same row and column.
This color arrangement is generally called "a mosaic arrangement".
FIG. 22 is a plan view showing an example of a pixel arrangement.
Numerals of -9 to 9 represent parallax numbers, and adjacent
parallax numbers are allocated to adjacent columns. A vertical
period of pixel rows is three times a lateral period Pp of
pixels.
[0098] Each pixel has an opening portion or a light emitting
portion at a fixed area ratio, and the opening portion is
surrounded by black matrixes 35. Since the pixel opening portions
and the black matrixes 35 form a period in a horizontal direction
in this manner and a lenticular sheet with a horizontal period of
integer times the period is superimposed on the pixels, moire or
color moire occurs on the display screen as a whole. In order to
reduce the moire, the haze of a diffusion layer on a surface of a
polarizing plate is set in a range of 20 to 70, so that an image of
pixels is burred in such an extent that neighboring pixels are not
mixed with each other. The diffusion layer is provided on a surface
of the polarizing plate of an ordinary liquid crystal display
device for preventing mirror reflection, but a diffusion layer with
a haze slightly stronger than that of the diffusion layer for
preventing mirror reflection is suitable for moire cancellation.
When the haze is smaller than 20, a sufficient moire reducing
effect cannot be achieved and when the haze is larger than 70,
neighboring pixels are mixed so that burring appearance occurs in
display. Therefore, the haze is required to be in a range of 20 or
more and 70 or less, and it is preferable that the haze is about
35. In order to achieve the object of the present invention, since
diffusion in a lateral direction is required to be moderate but it
is preferable that there is no diffusion in a vertical direction.
Therefore, there may be anisotropy in diffusion characteristic or
haze between the vertical direction and the lateral direction. The
diffusion layer may be integrated with a polarizing plate surface
of the liquid crystal display device, it may be integrated with a
back face of the lenticular sheet, or it may be an independent
diffusion sheet.
[0099] On the display plane shown in FIG. 21, one effective pixel
43 (the one effective pixel 43 is indicated by a black frame in
FIG. 21) is constituted of pixels 34 comprising 18 columns and 6
rows. In a structure of such a display portion, a stereoscopic
display applying 18 parallaxes in a horizontal direction is made
possible. Incidentally, when a parallax is applied in a vertical
direction too, a boundary of the effective pixel 43 in a horizontal
direction is regarded as an elemental image boundary in a vertical
direction to allocate two parallaxes is allocated in a vertical
direction so that the total of 36 parallaxes can be applied by
multiplying the two parallaxes in the vertical direction by the 18
parallaxes in the horizontal direction.
[0100] FIG. 21 shows a portion near the central portion of the
whole display plane, where the beam controlling element is
approximately positioned at the front of the elemental image (the
effective pixel).
[0101] In this display structure, the multiview system has 18
views, the elemental image pitch is 18-pixels pitch, and the
lateral pitch of the beam controlling element becomes smaller than
the 18-pixels pitch.
[0102] In the IP system, for example, in such a design that the
18-pixels pitch is equal to the parallax barrier pitch Ps, and a
set of parallel beams can be formed, an elemental image boundary
occurs at intervals (for example, 18.02) slightly larger than the
18-pixels width, so that the width of the effective pixel
corresponds to 18 columns or 19 columns depending on its position
within the display plane. That is, an average value of the
elemental image pitches is larger than the 18-pixels width and the
lateral pitch of the beam controlling element has 18-pixels width.
Since the effective pixel 43 has an aspect ratio of 1 and is
constituted in a square arrangement, displaying can be made with an
effective resolution in a vertical direction substantially equal to
an effective resolution in a horizontal direction. Accordingly,
production of a display image is made easy, and display data or
information applied to each image can be obtained relatively fast.
Like the first embodiment, the resolution in the vertical direction
is not required to match with the horizontal resolution
necessarily.
[0103] FIG. 29 is a flowchart showing a switching process between a
stereoscopic display mode and a flat display mode. At a
stereoscopic image display time, equal parallax image data or
information is applied to 6 pixels arranged in a vertical direction
in a straight line similar to a direction in which the opening
portion of the beam controlling element extends and at the same
position in a lateral direction by an effective pixel with a
generally square shape comprising pixels of 6.times.18 extending
vertically and horizontally within the range of the effective pixel
43, so that the total of 18 parallaxes and displaying is performed.
At a flat image display time where the beam controlling element is
detached or its function is invalidated, image signals is applied
to perform displaying by an effective pixel with a square shape
comprising 3 pixels of red, green and blue arranged horizontally.
Thus, it is made possible to change the resolution according to a
display aspect.
[0104] In an example of a display plane shown in FIG. 20, one
effective pixel 43 (the one effective pixel 43 is indicated by a
black frame in FIG. 20) is constituted of pixels 34 comprising 9
columns and 3 rows. In a structure of such a display portion, a
stereoscopic display applying 9 parallaxes in a horizontal
direction is made possible.
[0105] In the comparison table shown in FIG. 30, when a pixel
arrangement is not a delta arrangement, as shown in FIGS. 20 and
21, a combination of the elemental image or the parallax barrier
pitch of 9n times the pixel pitch, the beam controlling element
having optical openings extending in a vertical direction, and
pixels with an aspect ratio of 3:1 formed in a mosaic arrangement
is one of the most desirable constitutions is shown.
[0106] Further, in order to suppress flicker or cross talk in a
liquid crystal display device, a polarity reversing drive for each
field is frequently performed. However, when a color arrangement is
different from an ordinary one like this embodiment, particularly
when displaying is performed with a single color at the flat
display time where the beam controlling element is invalidated,
color flicker may occur. At a stereoscopic display time, since a
set of pixel rows which can be seen varies according to a position
of a viewpoint, flicker occurs partially in some case, even if a
simple signal line inversion drive (a V line inversion drive) or
the like is conducted. In order to prevent occurrence of flicker,
it is desirable that pixels with the same color closest to each
other in adjacent rows are driven in the same field by image
signals with different polarities, or pixels closest to each other
in the same column are driven in the same field by image signals
with different polarities, and it is further desirable that both
the operations are performed. That is, such a disposition that an
oblique direction along which colors are arranged and another
oblique direction along which the same polarities are arranged are
crossed, or such as a scanning line inversion drive (H line
inversion drive) is suitable. As examples showing an arrangement of
signal polarities in the same field, there are such patterns as
shown in FIG. 36 to FIG. 37. In FIG. 37, each two pixels closest to
each other in the same column have the same polarity, but pixels
with the same color closest to each other in the same column have
different polarities even in this case so that an effect or
advantage can be expected to some extent.
[0107] Even in this embodiment, explanation will be made, assuming
that, as one example of a case that counting is made based upon a
pixel group of the minimum unit forming a square, the number of
pixels in a flat display device is 1920 in a lateral direction (a
horizontal direction) and is 1200 in a longitudinal direction (a
vertical direction) and a pixel group of each minimum unit includes
pixels of red, green and blue (RGB). FIG. 23 or FIG. 24 is a
diagram schematically showing a horizontal section of a display
portion of a stereoscopic display device. As shown herein, a pitch
Ps (period) of the slit 333 or the lenticular lens of the
lenticular sheet 334 in a horizontal direction is set to a size of
an integer number of pixels correctly. That is, a center axis 351
passing through the center between respective slits 333 or a
reference axis 353 passing through a boundary between adjacent
lenticular lenses of the lenticualr sheet 334 passes through a
pixel boundary. An integer number of pixels are arranged in region
corresponding to a space between the center axes 351 or the
reference axes 352, and a pitch Ps (period) of the center axes 351
or the reference axes 352 in a horizontal direction is set to a
constant value. FIG. 25 is a diagram schematically showing the
front of the display portion of the stereoscopic display device. In
the example shown here, the pitch Ps is set to a size of 18 pixels.
A gap between the display plane 331 and the parallax barrier 332,
334 of the display device is effectively set to about 2 mm
considering the refractive index of glass substrate or lens
material. Thus, such a constitution that the pitch Ps of the
parallax barrier (not the pitch Ps which can be seen due to a
difference in distance but an actual pitch Ps of the parallax
barrier) is integer times the pixel-to-pixel pitch Pp is the
one-dimensional integral photography, as explained above. On the
other hand, such a constitution that the elemental image pitch Pe
is integer times the pixel-to-pixel pitch Pp like the horizontal
section shown in FIG. 26 is generally classified to the multiview
system.
[0108] FIG. 25 and FIG. 27 are conceptual diagrams of arrangement
methods of images on display planes of the display devices in the
IP system and the multiview system, obtained when a display portion
of a stereoscopic display device has been viewed from the front
thereof. The display plane of the display device is divided to
elemental images 370 corresponding to respective apertures (opening
portions of a parallax barrier), and each elemental image 370 is
constituted of pixel columns comprising 18 columns or 19 columns in
the IP system. The total number of pixel columns which can be
allocated with a parallax is 5760, because each pixel comprises
three sub-pixels and a positional shift occurs between two rows,
the number of apertures is 320 (in FIG. 25 and FIG. 27, the range
of aperture numbers described in a region shown by reference
numeral 364 is a range indicated by #-160 to #-1, and #1 to #160),
and the aperture pitch Ps is equal to a size of a 18-pixels width.
In FIG. 25 and FIG. 27, in each pixel column 365, corresponding
parallax numbers (in this example, corresponding to 34 directions
of parallax numbers -17 to -1 and 1 to 17) are shown as items in a
region indicated by a reference numeral 363. An elemental image
indicated by aperture number #1 comprises columns of 18 parallaxes
of parallax numbers -9 to -1 and 1 to 9, and an elemental image
indicated by aperture number #-159 comprises columns of 18
parallaxes of parallax numbers -17 to -1 and 1 to 18. Since the
width of the elemental image is slightly larger than the width of
the 18-pixels column, when the boundary of the elemental image is
caused to match with the closest pixel row boundary (a normal A-D
conversion), the number of pixel columns in the aperture is 18 in
most apertures, but aperture corresponding to 19 columns also
occur. The parallax number range in the aperture is shifted one by
one from the aperture number corresponding to 19 columns. The
aperture numbers corresponding to 19 columns are #10, #30, #49,
#69, #88, #107, #127, and #146 (and their minus numbers) (in case
of the viewing distance of 700 mm).
[0109] In FIG. 28, aperture numbers (Slit Number in Table)
indicating start and end of arrangement of parallax images in each
direction are shown. In this Table, pixel row numbers at
corresponding 3-D display time, and column numbers and pixel column
numbers of the flat display device are also shown.
[0110] Incidentally, unlike the IP system, in the multiview system,
the elemental image widths all comprise a width of 18 pixel
columns, as shown in FIG. 27, and parallax numbers of -9 to -1 and
1 to 9 are similarly arranged in all of the elemental images.
[0111] A Table (mosaic, the number of parallax: 18) shown in FIG.
31B is a table that, when the elemental image pitch or the parallax
barrier pitch is 18 times the pixel pitch and a liquid crystal
panel having the number of pixels defined by a normal standard is
used for the flat image display portion, excess rows or columns may
occur. Like the first embodiment, after an excess region is
allocated symmetrically, the excess region may be utilized in the
same manner as shown in FIGS. 32A, 32B and 32C. In order to make
symmetrical, in the multiview system, such a constitution can be
employed that boundaries of all the elemental images are set in a
middle between pixel centers of two pixels closest to each other in
an oblique direction of rows adjacent in a vertical direction, and
the total number of elemental images is even. In the IP system,
such a constitution may be employed that the total number of
elemental images is even and the boundary of the elemental image at
the central position on the whole display plane in a lateral
direction is set at a middle between pixel centers of two pixels
closest to each other in an oblique direction of rows adjacent in a
vertical direction. Incidentally, since the arrangement in this
embodiment is not the delta arrangement, "in a middle between pixel
centers of two pixels closest to each other in an oblique
direction" is the same as "in an middle between pixel centers of
two pixels closest in a lateral direction".
[0112] As described above, according to the stereoscopic display
devices according to the embodiments of the present invention, it
is made possible to simultaneously satisfy such a condition that,
while moire or color moire is suppressed, an aspect ratio of a
pixel is set to 1 and pixels are formed in a square arrangement so
that color data or information is prevented from lacking for each
parallax, and such a condition that a resolution or an image
quality does not vary largely at a time of switching between the
flat image display and the stereoscopic image display.
[0113] The present invention is not limited to the above
embodiments as they are, but it can be embodied in a practical
stage by modifying constituent elements without departing from the
spirit and scope of the invention.
[0114] Various inventions can be constituted by properly combining
a plurality of constituent elements disclosed in the above
embodiments. For example, some constituent elements of all the
constituent elements shown in the embodiments can be cancelled.
Further, constituent elements over a different embodiment may be
combined properly.
* * * * *