U.S. patent application number 14/985371 was filed with the patent office on 2016-04-21 for three-dimensional display apparatus.
The applicant listed for this patent is Samsung Display Co., LTD.. Invention is credited to Kyung-Ho JUNG, Hee-Seop KIM, Sung-Woon KIM, Seung-Hoon LEE, Jiangang LU, Hae-Young YUN.
Application Number | 20160109753 14/985371 |
Document ID | / |
Family ID | 41725065 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160109753 |
Kind Code |
A1 |
YUN; Hae-Young ; et
al. |
April 21, 2016 |
THREE-DIMENSIONAL DISPLAY APPARATUS
Abstract
A display device includes; a display panel, a lens substrate
facing the display panel, an air layer disposed between the display
panel and the lens substrate, and a light refraction portion
disposed on a surface of the lens substrate facing the display
panel, wherein an average refractive index of the light refraction
portion taken along a plane substantially parallel to the display
panel increases in a direction substantially parallel to a path of
light from the display panel to the lens substrate.
Inventors: |
YUN; Hae-Young; (Suwon-si,
KR) ; JUNG; Kyung-Ho; (Seoul, KR) ; LEE;
Seung-Hoon; (Yongin-si, KR) ; KIM; Sung-Woon;
(Suwon-si, KR) ; LU; Jiangang; (Suwon-si, KR)
; KIM; Hee-Seop; (Hwaseong-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Display Co., LTD. |
Yongin-City |
|
KR |
|
|
Family ID: |
41725065 |
Appl. No.: |
14/985371 |
Filed: |
December 30, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
14019095 |
Sep 5, 2013 |
9229262 |
|
|
14985371 |
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|
12476380 |
Jun 2, 2009 |
8553332 |
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14019095 |
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Current U.S.
Class: |
349/57 |
Current CPC
Class: |
G02F 1/133526 20130101;
G02F 2001/133562 20130101; G02F 2001/133567 20130101; G02B 30/27
20200101; G02F 1/133502 20130101; G02F 1/133528 20130101 |
International
Class: |
G02F 1/1335 20060101
G02F001/1335; G02B 27/22 20060101 G02B027/22 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 28, 2008 |
KR |
10-2008-0084441 |
Claims
1. A display device comprising: a display panel; and a plurality of
lenses disposed on the display panel, each lens comprising a convex
surface and a flat surface, wherein the convex surface of the lens
is disposed toward a surface of the display panel from which light
is emitted before being received by the lens.
2. The display device of claim 1, further comprising: a lens
substrate disposed on the plurality of lenses, wherein the flat
surface of the lens is disposed between the lens substrate and the
convex surface of the lens.
3. The display device of claim 2, wherein the lens substrate is
directly contacted with the flat surface of the lens.
4. The display device of claim 2, further comprising: a spacer
disposed between the display panel and an edge of the lens
substrate.
5. The display device of claim 4, wherein the spacer combines the
lens substrate and display panel to each other.
6. The display device of claim 4, wherein the spacer is not
overlapped with the plurality of lenses in a plan view.
7. The display device of claim 4, further comprising: a chassis
enclosing the display panel, wherein the spacer contacts an outer
surface of the chassis and the edge of the lens substrate.
8. The display device of claim 4, further comprising: a chassis
enclosing the display panel and the lens substrate.
9. The display device of claim 1, wherein the surface of the
display panel and the lens are disposed apart from each other.
10. The display device of claim 9, further comprising: an air layer
in a portion that the surface of the display panel and the lens are
disposed apart from each other.
11. The display device of claim 9, further comprising: a
light-transmitting portion in a portion that the surface of the
display panel and the lens are disposed apart from each other.
12. The display device of claim 11, wherein the light-transmitting
portion comprises a refractive isotropic material.
13. The display device of claim 1, wherein the display panel is a
liquid crystal display.
14. The display device of claim 1, further comprising: an upper
polarizer disposed above the display panel.
15. The display device of claim 14, wherein the upper surface of
the upper polarizer is treated by a low reflection surface
treatment.
16. The display device of claim 14, further comprising: a lower
polarizer disposed below the display panel.
17. The display device of claim 1, further comprising: a first
layer disposed on the plurality of lenses.
18. The display device of claim 17, further comprising: a lens
substrate disposed between the first layer and the plurality of
lenses, wherein the flat surface of the lens is disposed between
the lens substrate and the convex surface of the lens.
19. The display device of claim 18, wherein the first layer is a
low reflection surface layer.
20. A display device comprising: a display panel; a lens substrate
overlapping the display panel; a lens between the display panel and
the lens substrate, the lens comprising a convex surface and a flat
surface; a first polarizer disposed on the display panel; an air
layer disposed between the first polarizer and the lens, and a
spacer disposed between the display panel and an edge of the lens
substrate, wherein the convex surface of the lens is disposed
toward a surface of the display panel from which light is emitted
therefrom before being received by the lens.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/019,095, filed on Sep. 5, 2013, which is a
divisional of U.S. patent application Ser. No. 12/476,380, filed on
Jun. 2, 2009, which claims priority to Korean Patent Application
No. 10-2008-0084441, filed on Aug. 28, 2008, and all the benefits
accruing therefrom under 35 U.S.C. .sctn.119, the contents of which
in its entirety are herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] (a) Field of the Invention
[0003] The present invention relates to a three-dimensional ("3D")
image display device having a reverse phase lens structure.
[0004] (b) Description of the Related Art
[0005] Fast communication services based on the information
superhighway are expected to evolve from simpler audio-based
services, such as a current telephone service, to audible and
visual multimedia services utilizing digital terminals processing
characters, voices, and images quickly. Such services are
eventually expected to be applied to 3D communication services that
enable realistic and stereoscopic viewing and hearing, overcoming
temporal and spatial limitations.
[0006] Typically, a 3D image is expressed by a principle of stereo
vision of two eyes. Binocular disparity (e.g., a disparity images
perceived by each of two eyes caused because they are separated
apart by a distance of about 65 mm) plays an important role in a
stereoscopic effect. That is, when left and right eyes view a 3D
reality, each eye individually generates different 2D images and
the two images are transmitted to the brain, the brain combines the
two images to perceive depth in the original 3D reality. Such an
ability is usually called stereography.
[0007] 3D image display schemes using the binocular disparity are
typically categorized, depending on a necessity for spectacles, as
stereoscopic schemes such as a polarization scheme and a time
divisional scheme, and autostereoscopic schemes such as a parallax
barrier scheme and a lenticular scheme.
[0008] According to the stereoscopic schemes, a mass of people may
simultaneously enjoy 3D images from all viewing angles if the
polarization spectacles or liquid crystal shutter spectacles are
worn. However, due to a drawback that the polarization spectacles
or liquid crystal shutter spectacles must be worn, the stereoscopic
schemes are not commonly used, and the stereoscopic schemes are
typically limited to use in movie theatres.
[0009] In contrast, according to the various autostereoscopic
schemes, there is a merit that additional spectacles are not
required when enjoying the stereoscopic image.
[0010] Recently, according to the demands of the large scale and
the reduction of thickness of display devices, techniques for
reducing the weight and thickness of the display devices are
required. Also, if the viewing angle is increased, the 3D visible
region where the stereoscopic image can be shown is limited by
increasing confusion between images viewed at each position within
the viewing angle such that it is necessary to expand the 3D
visible region through the wide viewing angle.
BRIEF SUMMARY OF THE INVENTION
[0011] Accordingly, the present invention improves
three-dimensional ("3D") display quality, and realizes a reduction
of weight and thickness of a 3D module by applying a reverse phase
lens structure.
[0012] An exemplary embodiment of a display device according to the
present invention includes; a display panel, a lens substrate
facing the display panel, an air layer disposed between the display
panel and the lens substrate, and a light refraction portion
disposed on a surface of the lens substrate facing the display
panel, wherein an average refractive index of the light refraction
portion taken along a plane substantially parallel to the display
panel increases in a direction substantially parallel to a path of
light from the display panel to the lens substrate.
[0013] In one exemplary embodiment, the light refraction portion
may have a lens including a convex surface and a flat surface, and
the convex surface may be oriented toward the display panel, and
the flat surface may contact the lens substrate.
[0014] In one exemplary embodiment, the lens may be made of a
thermal hardening resin.
[0015] In one exemplary embodiment, a surface of the lens may be
treated by the low reflection surface treatment.
[0016] In one exemplary embodiment, a low reflection surface layer
formed on the lens substrate may be further included.
[0017] In one exemplary embodiment, a spacer disposed between the
display panel and an edge of the lens substrate may be further
included.
[0018] In one exemplary embodiment, a thickness of the spacer may
be controlled such that a thickness of the air layer disposed
between the lens substrate and the display panel may be
controlled.
[0019] In one exemplary embodiment, a chassis enclosing the display
panel may be further included, and the spacer may contact an outer
surface of the chassis and the edge of the lens substrate.
[0020] In one exemplary embodiment, a chassis enclosing the display
panel and the lens substrate may be further included.
[0021] In one exemplary embodiment, an upper polarizer and a lower
polarizer respectively disposed above and below the display panel
may be further included.
[0022] In one exemplary embodiment, the upper surface of the upper
polarizer may be treated by a low reflection surface treatment.
[0023] Another exemplary embodiment of an image display device
according to the present invention includes; a display panel, a
light-transmitting portion disposed on the display panel and
comprising a refractive isotropic material, a substrate facing the
display panel, and a light refraction portion disposed between the
substrate and the light-transmitting portion and comprising a
refractive anisotropic material.
[0024] In one exemplary embodiment, the light refraction portion
may include a refractive anisotropic material including a portion
having substantially the same refractive index as the material of
the light-transmitting portion, and a portion having a larger
refractive index than the light-transmitting portion.
[0025] In one exemplary embodiment, a low reflection surface layer
disposed on the substrate may be further included.
[0026] In one exemplary embodiment, a spacer disposed between the
display panel and an edge of the substrate may be further
included.
[0027] In one exemplary embodiment, an upper polarizer and a lower
polarizer respectively disposed above and below the display panel
may be further included.
[0028] According to the present invention, resolution of the same
degree as the front direction is maintained when increasing the
viewing angle such that the 3D wide viewing angle may be realized,
and the number of air layers between the panel and the module
outermost surface is reduced such that transmittance may be
improved. Also, the number of air layers is reduced such that the
reflection of surrounding light is reduced and visibility is
improved, and the number of component elements is reduced to
thereby realize a reduction of weight and thickness of the 3D
module.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a cross-sectional view of an exemplary embodiment
of a three-dimensional ("3D") image display according to the
present invention.
[0030] FIG. 2 is a cross-sectional view of another exemplary
embodiment of a 3D image display device according to the present
invention.
[0031] FIG. 3A is a schematic view illustrating the degree of image
formation according to an increase in viewing angle according to a
normal lens structure.
[0032] FIG. 3B is a schematic view illustrating the degree of image
formation according to an increase in viewing angle according to a
reverse lens structure.
[0033] FIG. 4 is a photograph comparing the display qualities of a
3D image display device using a normal lens structure and a 3D
image display device using a reverse lens structure as seen from a
front direction and a side direction.
[0034] FIG. 5 is a graph illustrating a confusion degree according
to a viewing angle of a 3D image display device using a normal lens
structure and a 3D image display device using a reverse lens
structure.
DETAILED DESCRIPTION OF THE INVENTION
[0035] The invention now will be described more fully hereinafter
with reference to the accompanying drawings, in which exemplary
embodiments of the invention are shown. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein. Rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. Like reference numerals
refer to like elements throughout.
[0036] It will be understood that when an element is referred to as
being "on" another element, it can be directly on the other element
or intervening elements may be present therebetween. In contrast,
when an element is referred to as being "directly on" another
element, there are no intervening elements present. As used herein,
the term "and/or" includes any and all combinations of one or more
of the associated listed items.
[0037] It will be understood that, although the terms first,
second, third etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another element,
component, region, layer or section. Thus, a first element,
component, region, layer or section discussed below could be termed
a second element, component, region, layer or section without
departing from the teachings of the present invention.
[0038] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," or "includes"
and/or "including" when used in this specification, specify the
presence of stated features, regions, integers, steps, operations,
elements, and/or components, but do not preclude the presence or
addition of one or more other features, regions, integers, steps,
operations, elements, components, and/or groups thereof.
[0039] Furthermore, relative terms, such as "lower" or "bottom" and
"upper" or "top," may be used herein to describe one element's
relationship to another elements as illustrated in the Figures. It
will be understood that relative terms are intended to encompass
different orientations of the device in addition to the orientation
depicted in the Figures. For example, if the device in one of the
figures is turned over, elements described as being on the "lower"
side of other elements would then be oriented on "upper" sides of
the other elements. The exemplary term "lower", can therefore,
encompasses both an orientation of "lower" and "upper," depending
on the particular orientation of the figure. Similarly, if the
device in one of the figures is turned over, elements described as
"below" or "beneath" other elements would then be oriented "above"
the other elements. The exemplary terms "below" or "beneath" can,
therefore, encompass both an orientation of above and below.
[0040] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and the present
disclosure, and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0041] Exemplary embodiments of the present invention are described
herein with reference to cross section illustrations that are
schematic illustrations of idealized embodiments of the present
invention. As such, variations from the shapes of the illustrations
as a result, for example, of manufacturing techniques and/or
tolerances, are to be expected. Thus, embodiments of the present
invention should not be construed as limited to the particular
shapes of regions illustrated herein but are to include deviations
in shapes that result, for example, from manufacturing. For
example, a region illustrated or described as flat may, typically,
have rough and/or nonlinear features. Moreover, sharp angles that
are illustrated may be rounded. Thus, the regions illustrated in
the figures are schematic in nature and their shapes are not
intended to illustrate the precise shape of a region and are not
intended to limit the scope of the present invention.
[0042] Hereinafter, the present invention will be described in
detail with reference to the accompanying drawings.
[0043] FIG. 1 is a cross-sectional view illustrating an exemplary
embodiment of a three-dimensional ("3D") image display device
according to the present invention.
[0044] Referring to FIG. 1, an exemplary embodiment of a 3D image
display device according to the present invention includes a
display panel 300, a stereoscopic image formation unit 400, an
upper polarizer 22, and a lower polarizer 12. Also, to support the
constituent elements the 3D image display device includes a fixing
unit 650 including a first fixing unit 620 and a second fixing unit
610, a spacer 630, a chassis 670, and a supporting unit 100.
[0045] Now, an exemplary embodiment of the display panel 300, which
in the present exemplary embodiment is a liquid crystal display
("LCD"), as an image panel will be described in more detail.
[0046] The display panel 300 includes a thin film transistor
("TFT") substrate 310, a color filter substrate 320, and a liquid
crystal layer 330.
[0047] Firstly, the TFT substrate 310 includes signal lines such as
a gate line and a data line, and is formed with a TFT (not shown)
and a pixel electrode (not shown) per pixel area, which in one
exemplary embodiment may be bound by the gate line and the data
line. Here, the TFT controls the application of image signals
transmitted through the data line to the pixel electrode according
to scanning signals transmitted through the gate line.
[0048] The display panel 300 is usually categorized as, depending
on shape of the pixel electrode, a backlit display panel, a
reflective display panel, or a transflective display panel which
includes characteristics of the backlight display panel and the
reflective display panel, and a display panel of any type may be
used as the 3D image display device according to an exemplary
embodiment of the present invention.
[0049] The color filter substrate 320 faces the TFT substrate 310
with a predetermined interval therebetween. The color filter
substrate 320 is formed with a color filter 340, and in exemplary
embodiments, although not shown, a black matrix, a common
electrode, and various other components, may be formed thereon.
[0050] In one exemplary embodiment, red, green, and blue color
filters are disposed for the color filter 340 to display the same
color according to the color filter pixel row, however various
alternative exemplary embodiments of color filter arrangements may
be used. According to the present exemplary embodiment each pixel
row consists of pixels disposed according to a direction of
extension of the data line.
[0051] A liquid crystal material is injected between the TFT
substrate 310 and the color filter substrate 320 to form the liquid
crystal layer 330. According to the liquid crystal arrangement of
the liquid crystal layer 330, the liquid crystal display may have
various display modes, and a twisted nematic ("TN") mode, a
patterned vertical alignment ("PVA") mode, and an electrically
controlled birefringence ("ECB") mode have been mainly used. If the
TN mode is described as an example of the present exemplary
embodiment, the TN mode has retardation such that polarization axis
rotation of 90 degree is generated under a state in which an
electric field is not applied to the liquid crystal layer 330.
[0052] The upper polarizer 22 and the lower polarizer 12 are
disposed above and below the display panel 300, respectively.
[0053] Next, an exemplary embodiment of the stereoscopic image
formation unit 400, which is a core portion for forming a
stereoscopic image, will be described.
[0054] The stereoscopic image formation unit 400 refracts light
emitted from the display panel 300 and distributes the light to
left or right eyes in order to form a 3D image. The stereoscopic
image formation unit 400 includes a lens 420, a lens substrate 430,
and a low reflection surface layer 440.
[0055] A plurality of lenses 420 disposed in a row direction are
formed on the surface of the lens substrate 430 facing the display
panel 300. In one exemplary embodiment, the lens 420 has a shape of
a curvature column that is vertically cut. Exemplary embodiments of
the curvature column include a circular cylinder and an elliptical
cylinder, and the cut position where the curvature column is
vertically cut is the center of the curvature column or away from
the center of the curvature column by a predetermined distance (in
one exemplary embodiment the predetermined distance is more than 0
and less than the radius of the center of the curvature column).
That is, in one exemplary embodiment the lens 420 has a convex
surface and a flat surface. In one exemplary embodiment the cut
columns extend substantially along the length of the stereoscopic
image formation unit (shown as being into the page in the
cross-sectional view of FIG. 1). The lens 420 has the function of
refracting the light and realizing multi-view images. In one
exemplary embodiment, the lens 420 may be made using a thermal
hardening resin.
[0056] The lens substrate 430 contacts the flat surface of the lens
420, and the convex portion of the lens 420 is formed in the
direction facing the display panel 300. This structure is
distinguished from a conventional structure wherein the convex
portion of the lens is formed in the direction from which a viewer
sees the images, and the flat portion of the lens is disposed
toward the display panel. Accordingly, in the conventional lens
structure, a protection plate is additionally required on the lens
as well as a lens substrate supporting the lens. Also, in the
conventional lens structure an air layer is required with a
predetermined thickness to prevent the lens from directly
contacting the protection glass plate, and the thickness of the
entire 3D display is thereby increased. In the current exemplary
embodiment of a display device according to the present invention,
the lens substrate 430 itself has a function of a protection glass
such that a separate protection plate is not required and the
thickness of the display device is decreased, and the number of air
layers is decreased such that the transmittance is improved and the
visibility is improved.
[0057] The low reflection surface layer 440 is formed on the lens
substrate 430. The low reflection surface layer 440 has a function
of preventing reflection of incident light. Accordingly, the
exemplary embodiment of a display device according to the present
invention may improve the visibility in a bright environment. The
low reflection surface layer 440 covers a base film (not shown) on
the lens substrate 430, and in one exemplary embodiment may be
formed by alternately depositing a material having a high
refractive index and a material having a low refractive index.
[0058] The display panel 300 is attached to the supporting unit 100
to protect the 3D image display device of the present invention.
The first fixing unit 620 fixes the display panel 300 between the
supporting unit 100 and the display panel 300. The chassis 670
encloses the side surface edge of the supporting unit 100 and the
upper surface edge of the supporting unit 100. The second fixing
unit 610 may be disposed between the vertical portion of the
chassis 670 and the side surface of the supporting unit 100. The
spacer 630 is formed between the vertical portion of the chassis
670 and the edge of the lens substrate 430. The spacer 630 combines
the stereoscopic image formation unit 400 and the display panel 300
to each other, and functions to form an air layer A between the
lens substrate 430 and the upper polarizer 22. In one exemplary
embodiment, the thickness of the air layer A may be determined by
the thickness of the spacer 630. In one exemplary embodiment, the
lens 420 may not be formed on the edge of the lens substrate 430 in
contact with the spacer 630. While one exemplary embodiment of a
supporting unit 100, fixing unit 650 and chassis 670 have been
described, alternative exemplary embodiments include alternative
configurations to orient, fix and support the display panel 300
with respect to the stereoscopic image formation unit 400.
[0059] The thickness of the air layer A may be determined by the
condition of the image formation. The thickness of the medium is
increased according to an increase of the refractive index of the
medium, and since the air layer A has a refractive index of 1.0
that is less than the refractive index of 1.5 of glass, when the
air layer A is formed between the upper polarizer 22 and the lens
420, the thickness may be thinner than if the glass were formed
between the polarizer 22 and the lens 420. Also, the convex portion
of the lens 420 does not directly contact the upper polarizer 22
and is away therefrom such that the air layer A prevents the
formation of an interference pattern.
[0060] Referring to FIG. 1, another exemplary embodiment that is
different from the previous exemplary embodiment of the present
invention will be described.
[0061] Referring again to FIG. 1, a light-transmitting portion made
of an isotropic material may be formed in the air layer A. The
light-transmitting portion does not reflect light that is incident
from the display panel 300 and may transmit the light without
modification. A light refraction portion may be formed between the
light-transmitting portion and the lens substrate 430 to replace
the lens 420. It is not necessary for the light refraction portion
to have a convex surface. In one exemplary embodiment, the light
refraction portion may be made of an anisotropic material. The
light refraction portion may be made of the anisotropic material
including a portion having substantially the same refractive index
as that of the material of the light-transmitting portion and a
portion having a larger refractive index than that of the material
of the light-transmitting portion. When the material is limited as
described above, the same effects as those of the exemplary
embodiment of a reverse lens structure that is described above may
be obtained.
[0062] FIG. 2 is a cross-sectional view of another exemplary
embodiment of a 3D image display device according to the present
invention.
[0063] Referring to FIG. 2, the main constituent elements are
substantially similar to those of the exemplary embodiment of a
display device illustrated with reference to FIG. 1. However, the
display device of FIG. 1 has the structure in which the
stereoscopic image formation unit 400 is attached to the chassis
670 of a 2D LCD, and the exemplary embodiment shown in FIG. 2 has a
structure that is combined with the chassis 670 after the
supporting unit 100 and the stereoscopic image formation unit 400
enclosing the display panel 300 are combined.
[0064] FIG. 3A is a schematic view illustrating the degree of image
formation according to an increase in viewing angle according to a
normal lens structure, and FIG. 3B is a schematic view illustrating
the degree of image formation according to an increase in the
viewing angle according to a reverse lens structure.
[0065] Referring to FIGS. 3A and 3B, the lines represent the
respective light paths corresponding to the viewpoints V1, V2, and
V3 of a viewer at various locations external to the display, and
P1, P2, and P3 represent portions of the color filter among a
plurality of color filters CF. V1 is a view point of the front
direction of the display device, and the viewing angle is increased
toward V2 and V3.
[0066] Firstly, the normal lens structure will be described with
respect to FIG. 3A. As seen from the view point V1, the image
generated from the color filter P1 is formed into a clear image, as
shown in FIG. 3. However, the phase is changed according to an
increase of the viewing angle, and the image formation is not
generated on the view point V3. The focal distance, represented
herein by the lightly shaded structure, is decreased according to
the increasing of the viewing angle, the several images generated
from the color filter P3 are simultaneously recognized at the view
point V3 such that confusion, e.g., an area of low resolution, is
generated and no coherent image results.
[0067] Referring now to FIG. 3B, the reverse lens structure will be
described. Although the viewing angle is increased moving from V1
to V2 to V3, the change of the image is small. In other words,
although the viewing angle is increased, the degree that the focal
distance is reduced is much smaller than that of the normal lens
structure. In the 3D optical system, the focus is desirable to be
appropriately large, and the change according to the viewing angle
is desired to be small. In the exemplary embodiment of a display
device according to the present invention, the reverse lens
structure is applied such that although the viewing angle is
increased, the reduction of the focus is small, and the wide
viewing angle characteristic may be realized, e.g., even though the
viewing angle is large, little to no confusion is generated and a
coherent image results.
[0068] FIG. 4 is a photograph comparing the display qualifies of a
3D image display device using a normal lens structure and a 3D
image display device using a reverse lens structure as seen from a
front direction and a side direction.
[0069] Referring to FIG. 4, the differences of the display
qualities for the normal lens structure and the reverse lens
structure are small when viewing from the front direction. However,
when viewing from the side direction, the display quality of the
reverse lens structure is clearer than the display quality of the
normal lens structure.
[0070] FIG. 5 is a graph illustrating a confusion degree according
to a viewing angle of a 3D image display device using a normal lens
structure and a 3D image display device using a reverse lens
structure. As used herein the confusion corresponds to the
resolution of the stereoscopic image, and if the confusion is
increased, the resolution is decreased.
[0071] Referring to FIG. 5, when the normal lens structure is
applied, as indicated by a graph line F, the confusion is largely
increased according to the increase of the viewing angle. However,
when applying the reverse lens structure, as indicated by a graph
line B, though the viewing angle is increased, the change of the
confusion is not large.
[0072] While this invention has been described in connection with
what is presently considered to be practical exemplary embodiments,
it is to be understood that the invention is not limited to the
disclosed embodiments, but, on the contrary, is intended to cover
various modifications and equivalent arrangements included within
the spirit and scope of the appended claims.
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