U.S. patent application number 13/088695 was filed with the patent office on 2012-03-29 for 3 dimensional image display device.
Invention is credited to Jae-Sung BAE, Jai-Hyun KOH, Bong-Hyun YOU.
Application Number | 20120075289 13/088695 |
Document ID | / |
Family ID | 45870177 |
Filed Date | 2012-03-29 |
United States Patent
Application |
20120075289 |
Kind Code |
A1 |
KOH; Jai-Hyun ; et
al. |
March 29, 2012 |
3 DIMENSIONAL IMAGE DISPLAY DEVICE
Abstract
A 3D image display device includes a display device including a
plurality of pixels and displaying each of a left-eye image and a
right-eye image. The display device inserts an insertion image
between the left-eye image and the right-eye image such that the
left-eye image is displayed for part of four frames and the
insertion image is displayed for the remaining frames and the
right-eye image is displayed for part of four other frames and the
insertion image is displayed for the remaining other frames.
Inventors: |
KOH; Jai-Hyun; (Seoul,
KR) ; YOU; Bong-Hyun; (Yongin-si, KR) ; BAE;
Jae-Sung; (Suwon-si, KR) |
Family ID: |
45870177 |
Appl. No.: |
13/088695 |
Filed: |
April 18, 2011 |
Current U.S.
Class: |
345/419 |
Current CPC
Class: |
H04N 13/341 20180501;
H04N 13/30 20180501; H04N 13/398 20180501; H04N 1/6005
20130101 |
Class at
Publication: |
345/419 |
International
Class: |
G06T 15/00 20110101
G06T015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2010 |
KR |
10-2010-0093704 |
Claims
1. A 3D image display device, comprising: a display device
including a plurality of pixels and displaying each of a left-eye
image and a right-eye image, wherein the display device inserts an
insertion image between the left-eye image and the right-eye image
such that the left-eye image is displayed for part of four frames
and the insertion image is displayed for the remaining frames and
the right-eye image is displayed for part of four other frames and
the insertion image is displayed for the remaining other
frames.
2. The device of claim 1, further comprising glasses including a
left lens and a right lens which are alternately turned on and off,
wherein the left lens is in an on state while the left-eye image is
displayed and a right lens is in the on state while the right-eye
image is displayed.
3. The device of claim 1, wherein the left-eye image or the
right-eye image is displayed for one frame and the insertion image
is displayed for three frames.
4. The device of claim 1, the left-eye image or the right-eye image
is displayed for two frames and the insertion image is displayed
for two frames.
5. The device of claim 1, wherein the left-eye image or the
right-eye image is displayed for three frames and the insertion
image is displayed for one frame.
6. The device of claim 2, wherein both the right lens and the left
lens are in an off state while the left-eye image and the right-eye
image are overlapped with each other in the display device.
7. The device of claim 1, wherein data representing an additional
luminance is additionally applied to least one of the left-eye
image, the right-eye image, and the insertion image to display an
image.
8. The device of claim 7, wherein: in any one of the four frames in
which the left-eye image and the insertion image are displayed and
the four frames in which the right-eye image and the insertion
image are displayed, the data representing the additional luminance
is applied to only one image of the first to third frames among the
four frames to be displayed.
9. The device of claim 7, wherein: in any one of the four frames in
which the left-eye image and the insertion image are displayed and
the four frames in which the right-eye image and the insertion
image are displayed, the data representing the additional luminance
is applied to both the images of the first and second frames among
the four frames to be displayed.
10. The device of claim 9, wherein the data representing the
additional luminance applied to the image of the first frame and
the data representing the additional luminance applied to the image
of the second frame have different intensities from each other.
11. The device of claim 9, wherein the data representing the
additional luminance applied to the image of the first frame and
the data representing the additional luminance applied to the image
of the second frame have the same intensity as each other.
12. The device of claim 7, further comprising a 3D image processor
adding the data representing the additional luminance to image data
for application to a frame.
13. The device of claim 12, wherein the 3D image processor
comprises: a gamma converter generating gamma-converted data from
image data; a luminance improver improving the luminance of the
gamma-converted data; and a reverse gamma converter reverse gamma
converting the data having the improved luminance.
14. The device of claim 13, wherein the gamma converter generates
output data having a bit number higher than the data input thereto,
and wherein the output data is generated by a lookup table.
15. The device of claim 13, wherein the 3D image processor further
includes a luminance improvement rate provider, wherein the
luminance improver includes a luminance improvement data generator
and a frame memory, wherein the luminance improvement data
generator generates data having improved luminance depending on a
luminance improvement rate provided from the luminance improvement
rate provider, and wherein the frame memory stores the data
generated by the luminance improvement data generator.
16. The device of claim 15, wherein: the luminance improvement data
generator generates data corresponding to total four frames through
Equation 2 if a result of Equation 1 is true, and generates data
corresponding to total four frames through Equation 3 if the result
is false. L*(MBTR+1)<Max L 10.sup.12 [Equation 1]
LN<=L*(MBTR+1) LN+1<=L*(MBTR+1) LN+2<=0 [Equation 2]
LN<=MAX L LN+1<=MAX L LN+2<={L*(MBTR+1)-MAX L}*2 [Equation
3] wherein L represents the luminance data inputted into the
luminance improvement data generator, MBTR represents a max boost
up threshold rate, Max L(10.sup.12) represents a maximum
displayable luminance, and LN, LN+1, and LN+2 represent luminance
data of an N frame, luminance data of an N+1 frame, and luminance
data of an N+2 frame, respectively.
17. The device of claim 13, wherein the reverse gamma converter
generates output data having a bit number less than the data input
thereto.
18. The device of claim 13, wherein the 3D image processor further
includes a balance rate provider, and wherein the balance rate
provider provides a rate for determining which of two frames data
representing an additional luminance is to be more greatly added to
when additional luminances are to be applied to the images of both
first frame and second frames.
19. The device of claim 18, wherein the balance rate is applied to
the luminance improver and considered when data corresponding to a
total four frames are generated in the luminance improver.
20. A 3D image display device, comprising: a display device
including a plurality of pixels, wherein the display device is
configured to display a left-eye image for between one to three
frames of four consecutive first frames followed by an all black
image for the remaining first frames, and wherein the display
device is configured to display a right-eye image for between one
to three frames of four consecutive second frames followed by the
same all black image for the remaining second frames.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Korean Patent
Application No. 10-2010-0093074 filed in the Korean Intellectual
Property Office on Sep. 28, 2010, the disclosure of which is
incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] (a) Technical Field
[0003] Embodiments of the present invention relate to a 3
dimensional image display device.
[0004] (b) Discussion of Related Art
[0005] A 3 dimensional image may be visualized by stereo vision
through both eyes. A binocular disparity is generated by a visual
disparity between both eyes, i.e., the distance between both eyes.
For example, the left and right eyes view different 2D images and
when both images are transferred to the brain through the retina,
the brain fuses the images to reproduce the original 3D image.
[0006] Autostereoscopy is a method of displaying stereoscopic (3D)
images without the use of special glasses on the part of the
viewer. An autostereoscopic 3D image display device may include a
lenticular lens layer disposed on a liquid crystal display.
However, with this display device, the images transferred to the
right and left eyes are not clearly discriminated, which produces a
3D effect with a low quality.
[0007] A stereoscopic 3D image display device has an additional
cost since it requires additional glasses, but allows many people
to view 3D images with improved quality since images transferred to
the left and right eyes can be more clearly discriminated.
SUMMARY OF THE INVENTION
[0008] At least one embodiment of the present invention has been
made in an effort to provide a 3 dimensional image display device
that improves 3D display quality and improves display luminance by
allowing images transferred to the right and left eyes to be more
clearly discriminated and recognized.
[0009] An exemplary embodiment of the present invention provides a
3D image display device which includes a display device having a
plurality of pixels and displaying each of a left-eye image and a
right-eye image. The display device inserts an insertion image
between the left-eye image and the right-eye image such that the
left-eye image is displayed for part of four frames and the
insertion image is displayed for the remaining frames, and the
right-eye image is displayed for part of four other frames and the
insertion image is also displayed for the remaining other
frames.
[0010] The device may further include glasses including a left lens
and a right lens which are alternately turned on and off. The left
lens may be in an on state while the left-eye image is displayed
and the right lens may be in the on state while the right-eye image
is displayed.
[0011] The left-eye image or the right-eye image may be displayed
for one frame and the insertion image is displayed for three frames
or the left-eye image or the right-eye image may be displayed for
two frames and the insertion image is displayed for two frames. The
left-eye image or the right-eye image may be displayed for three
frames and the insertion image may be displayed for one frame. Both
the left lens and the right lens may be in an off state while the
left-eye image and the right-eye image are overlapped with each
other in the display device.
[0012] Data representing additional luminance may be additionally
included in (or applied to) at least one of the left-eye image, the
right-eye image, and the insertion image to display an image.
[0013] In any one of four frames in which the left-eye image and
the insertion image are displayed and four frames in which the
right-eye image and the insertion image are displayed, the data
representing the additional luminance may be included in (or
applied to) only one image of the first to third frames among the
four frames to be displayed.
[0014] When the data representing the additional luminance is not
included in (or applied to) the image of the first frame, the data
may be included in (or applied to) the image of the second frame,
and when the data is not included in (or applied to) the image of
the second frame, the data may be included in (or applied to) the
image of the third frame.
[0015] In any one of four frames in which the left-eye image and
the insertion image are displayed and four frames in which the
right-eye image and the insertion image are displayed, the data
representing the additional luminance may be all included in (or
applied to) both the images of the first and second frames among
the four frames to be displayed.
[0016] The data representing the additional luminance included in
(or applied to) the image of the first frame and the data
representing the additional luminance included in (or applied to)
the image of the second frame may have different intensities from
each other. The data representing the additional luminance included
in (or applied to) the image of the first frame and the data
representing the additional luminance included in (or applied to)
the image of the second frame may have the same intensity as each
other.
[0017] The device may further include a 3D image processor adding
the data representing the additional luminance to image data for
application to a frame. The 3D image processor may include a gamma
converter generating gamma-converted data from image data, a
luminance improver improving the luminance of the gamma-converted
data, and a reverse gamma converter reverse gamma converting the
data having the improved luminance. The gamma converter may
generate output data having a bit number higher than the data input
thereto. The output data may be generated by a lookup table. The
reverse gamma converter may generate output data having a bit
number less than the data input thereto.
[0018] The 3D image processor may further include a luminance
improvement rate provider. The luminance improver may further
include a luminance improvement data generator and a frame memory.
The luminance improvement data generator may generate data having
an improved luminance depending on a luminance improvement rate
(e.g., a maximum boost up threshold rate) provided from the
luminance improvement rate provider. The frame memory may store the
data generated by the luminance improvement data generator.
[0019] The luminance improvement data generator may generate data
corresponding to a total four frames through Equation 2 if a result
of Equation 1 as below is true, and generate data corresponding to
a total four frames through Equation 3 if the result is false.
L*(MBTR+1)<Max L 10.sup.12 [Equation 1]
LN<=L*(MBTR+1)
LN+1<=L*(MBTR+1)
LN+2<=0 [Equation 2]
LN<=MAX L
LN+1<=MAX L
LN+2<={L*(MBTR+1)-MAX L}*2 [Equation 3]
[0020] wherein L represents the luminance data inputted into the
luminance improvement data generator 260, MBTR represents the
luminance improvement rate (max boost up threshold rate), Max
L(10.sup.12) represents a maximum displayable luminance, and LN,
LN+1, and LN+2 represent luminance data of an N frame, the
luminance data of an N+1 frame, and the luminance data of an N+2
frame, respectively. In Equation 2 and Equation 3, the luminance
data of the N+3 frame may be black data.
[0021] The 3D image processor may further include a balance rate
provider that provides a rate (a balance rate) for determining
which of two frames data representing an additional luminance is to
be more greatly added to when additional luminances are to be added
to both the first and second frames. The balance rate may be
applied to the luminance improver and considered when data
corresponding to a total four frames are generated in the luminance
improver.
[0022] According to at least one exemplary embodiment of the
present invention, a 3D image display device is provided that
allows an image transferred to a right eye and an image transferred
to a left eye to be more clearly discriminated and recognized.
Further other embodiments may additionally improve the display
quality of a 3D image by improving the luminance of a liquid
crystal display.
[0023] According to an exemplary embodiment of the invention, a 3D
image display device includes a display device having a plurality
of pixels. The display device is configured to display a left-eye
image for between one to three frames of four consecutive first
frames followed by an all black image for the remaining first
frames. The display device is configured to display a right-eye
image for between one to three frames of four consecutive second
frames followed by the same all black image for the remaining
second frames.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a schematic diagram showing an operation state of
a 3 dimensional image display device according to an exemplary
embodiment of the present invention.
[0025] FIG. 2 is a graph showing a signal waveform of the 3D image
display device according to the exemplary embodiment of FIG. 1.
[0026] FIG. 3 is a schematic diagram showing an operation state of
a 3 dimensional image display device according to an exemplary
embodiment of the present invention.
[0027] FIG. 4 is a graph showing a signal waveform of the 3D image
display device according to the exemplary embodiment of FIG. 3.
[0028] FIG. 5 is a schematic diagram showing an operation state of
a 3 dimensional image display device according to an exemplary
embodiment of the present invention.
[0029] FIG. 6 is a graph showing a signal waveform of the 3D image
display device according to the exemplary embodiment of FIG. 5.
[0030] FIGS. 7 to 13 are graphs showing a method of improving
luminance displayed by a 3D image display device according to an
exemplary embodiment of the present invention.
[0031] FIGS. 14 to 20 are diagrams showing the 3D image processor
of a signal controller of a 3D image display device according to an
exemplary embodiment of the present invention.
[0032] FIG. 21 is a graph showing improved luminance of a 3D image
display device according to an exemplary embodiment of the present
invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0033] The present invention will be described more fully
hereinafter with reference to the accompanying drawings, in which
exemplary embodiments of the invention are shown.
[0034] In the drawings, the thickness of layers, films, panels,
regions, etc., may be exaggerated for clarity. Like reference
numerals designate like elements throughout the specification. It
will be understood that when an element such as a layer, film,
region, or substrate is referred to as being "on" another element,
it can be directly on the other element or intervening elements may
also be present.
[0035] FIGS. 1 to 6 describe exemplary embodiments of the invention
that may reduce crosstalk in which a left-eye image and right-eye
image are misperceived by a right eye and left eye, respectively.
The embodiments may involve high-speed driving of left and right
eye images along with black images interposed between the driven
images.
[0036] FIG. 1 is a schematic diagram showing an operation state of
a 3 dimensional image display device according to an exemplary
embodiment of the present invention and FIG. 2 is a graph showing a
signal waveform of the 3D image display device according to the
exemplary embodiment of FIG. 1.
[0037] The 3D image display device includes a display device and
glasses. As an example, the display device may be a liquid crystal
display, an organic light emitting diode display, etc. Hereinafter,
the liquid crystal display will primarily be described as the
display device merely for ease of discussion.
[0038] The liquid crystal display includes a liquid crystal display
panel and a backlight unit (not shown). The liquid crystal display
panel includes a plurality of pixels. The liquid crystal display
panel controls the intensity of transmitted light by changing a
liquid crystal alignment direction using an electric field
generated between two electrodes to display an image.
[0039] The liquid crystal display panel may include an upper
substrate, a lower substrate, and a liquid crystal layer injected
or interposed between the upper substrate and the lower
substrate.
[0040] A gate line, a data line, a pixel electrode, and a thin film
transistor connected thereto may be formed on the lower substrate.
The thin film transistor controls a voltage applied to the pixel
electrode on the basis of signals applied to the gate line and the
data line. For example, the thin film transistor controls the
voltage applied to the pixel electrode by transmitting a voltage
applied to the data line from a source electrode to a drain
electrode of the thin film transistor and applying the
corresponding voltage to the pixel electrode connected with the
drain electrode if the voltage inputted through the gate line is
equal to or higher than a predetermined level. The pixel electrode
may be formed by a semi-transmissive pixel electrode having a
transmission region and a reflective region in some exemplary
embodiments. Further, a storage capacitor may be additionally
formed to sustain the voltage applied to the pixel electrode for a
predetermined duration. The thin film transistor and the pixel
electrode may form one pixel. A black matrix, a color filter, and a
common electrode may be formed on the upper substrate, which
opposes the lower substrate.
[0041] The liquid crystal layer between the upper substrate and the
lower substrate may have vertically aligned (VA)-mode liquid
crystals that are vertically aligned with respect to a substrate
surface when no electric field is applied between the common
electrode and the pixel electrode. However, embodiments of the
invention are not limited thereto, as the liquid crystal layer may
include liquid crystals of a twisted nematic (TN) mode, liquid
crystals of an electrically controlled birefringence (ECB) mode,
etc.
[0042] A polarizer may be attached onto each of an outer surface of
the upper substrate and an outer surface of the lower substrate. A
compensation film may be added between the substrate surface and
the polarizer in some exemplary embodiments.
[0043] At least one of the color filter, the black matrix, and the
common electrode that are formed on the upper substrate may be
formed on the lower substrate in some exemplary embodiments and
when both the common electrode and the pixel electrode are formed
on the lower substrate, at least one of both electrodes may be
formed as a linear electrode.
[0044] The backlight unit, which provides light to the liquid
crystal display panel, includes a lamp. A reflection plate, a light
guide plate, and a luminance enhancement film may used with the
backlight unit to guide light emitted from the lamp to toward the
liquid crystal display panel. A fluorescent lamp such as a cold
cathode fluorescent (CCFL) or an LED may be used as the lamp. Light
from the backlight unit is either transmitted to the liquid crystal
display panel or blocked. A gray is expressed depending on the
transmission level of the light.
[0045] A right lens and a left lens of the glasses are configured
to alternately block light at a predetermined cycle in
synchronization with the liquid crystal display panel. For example,
according to FIGS. 1 and 2, the light is first blocked (off) on the
right lens and transmitted (on) on the left lens. Thereafter, the
light is transmitted (on) on the right lens and blocked (off) on
the left lens. As a result, the image is perceived by only the left
eye for a predetermined duration and the image is perceived by only
the right eye for the subsequent predetermined duration. A 3D image
is perceived by a difference between the images perceived by the
left eye and the right eye.
[0046] As such, when the lenses of the glasses are on/off, the
image to be transferred to the left eye and the image to be
transferred to the right eye are displayed depending on the on and
off operations of the lenses, respectively on the liquid crystal
display panel.
[0047] Each of the images transferred to the left and right eyes
are displayed on the liquid crystal display panel. Black data is
inserted between both images to allow discrimination between the
image transferred to the left eye and the image transferred to the
right eye.
[0048] For example, the liquid crystal display panel displays the
image to be transferred to the left eye using N to N+3 frames in
FIG. 2. A frame inserted with the black data is shaded in FIG. 1.
The same notation is applied in FIGS. 3 and 5.
[0049] A gate-on voltage is sequentially applied to the gate line
to apply a data voltage to the pixel electrode through the thin
film transistor connected to the corresponding gate line. When this
occurs, the applied data voltage may be referred to as a left data
voltage, which is for expressing the image to be transferred to the
left eye. The applied left data voltage is sustained by the storage
capacitor for a predetermined duration. (See N frame of FIG. 2)
[0050] Thereafter, the gate-on voltage is sequentially applied to
the gate line again to apply a black data voltage to the pixel
electrode through the thin film transistor connected to the
corresponding gate line. When this occurs, the applied black data
voltage, which is used to display a black image inserted between
the image to be transferred to the left eye and the image to be
transferred to the right eye, may discriminate both images from
each other. The applied black data voltage is also sustained by the
storage capacitor for a predetermined duration. (See N+1 to N+3
frames of FIG. 2)
[0051] Thereafter, the liquid crystal display panel displays the
image to be transferred to the right eye as follows using N+4 to
N+7 frames of FIG. 2.
[0052] The gate-on voltage is sequentially applied to the gate line
to apply data voltage to the pixel electrode through the thin film
transistor connected to the corresponding gate line. When this
occurs, the applied data voltage may be referred to as right data
voltage, which is for expressing the image to be transferred to the
right eye. The applied right data voltage is sustained by the
storage capacitor for a predetermined duration. (See N+4 frame of
FIG. 2)
[0053] Thereafter, the gate-on voltage is sequentially applied to
the gate line again to apply the black data voltage to the pixel
electrode through the thin film transistor connected to the
corresponding gate line. When this occurs, the applied black data
voltage, which is used to display the black image inserted between
the image to be transferred to the left eye and the image to be
transferred to the right eye, may discriminate both images from
each other. Further, the applied black data voltage is also
sustained by the storage capacitor for a predetermined duration.
(See N+4 to N+7 frames of FIG. 2)
[0054] FIG. 2 shows the relationship between the operation of the
liquid crystal display panel and the on/off operation of the
glasses. The arrows emanating from the liquid crystal display panel
and their direction represent a sequence of applying the gate-on
voltage to respective gate lines. For example, in an exemplary
embodiment of the present invention, the arrow direction represents
that a gate-on signal is applied from an upper gate line to
subsequent gates lines of the panel to sequentially apply the
gate-on signal.
[0055] The liquid crystal display panel is shown with respect to 8
frames in FIG. 2. Referring to FIG. 2, a state in which an image
transferred from the left side to the left eye is displayed occurs
in the N frame, a state in which the black data is displayed occurs
in the N+1 to N+3 frames, a state in which the image transferred to
the right eye is displayed occurs in the N+4 frame, and a state in
which the black data is displayed occurs in the N+5 to N+7 frames.
In synchronization therewith, the left lens of the glasses is in an
on state and the right lens of the glasses is in an off state from
the N frame to the middle of the N+2 frame. Both lenses are in the
off state from the middle of the N+2 frame to the N+3 frame.
Further, the left lens is in the off state and the right lens is in
the on state from the N+4 frame to the middle of the N+6 frame.
Both lenses are in the off state from the middle of the N+6 frame
to the N+7 frame. The glasses may be set to change the on/off state
of the glasses every two frames of the liquid crystal display panel
and have a section in which both lenses are in the off state
therebetween. In the exemplary embodiment of the present invention,
each frame of the liquid crystal display panel may have an
inversion cycle of 480 Hz. However, embodiments of the present
invention are limited to any particular inversion cycle.
[0056] As a result, the image perceived by the left eye is an image
displayed in the N frame and the image perceived by the right eye
is an image displayed in the N+4 frame. As such, a sense of depth
is perceived since the images received by both eyes are different
from each other, thereby creating a 3D effect. The sense of depth
(distance) may be adjusted so that one perceives both objects are
more distant from each other by adjusting the difference between
the images perceived by both eyes.
[0057] Referring to FIG. 2, the left eye and the right eye of the
glasses are changed from the on state to the off state in the
middle of the N+2 frame and in the middle of the N+6 frame.
However, in alternate exemplary embodiments of the invention, the
time when the left eye and the right eye of the glasses are changed
from the on state to the off state may coincide with the start of
the N+2 frame and the start of the N+6 frame, or may be positioned
in the N+3 frame (e.g., at its start, its middle, etc) and in the
N+7 frame (e.g., at its start, middle, etc.). For example, unlike
FIG. 2, the left lens and the right lens may be changed from the on
state to the off state between the N+2 frame and the N+3 frame and
between the N+6 frame and the N+7 frame.
[0058] The image transferred to the left eye and the image
transferred to the right eye may be clearly discriminated from each
other by inserting the black data image.
[0059] When a data voltage is applied to the pixel electrode, a
predetermined time may be required to change an alignment direction
depending on an electric field generated by the applied data
voltage on the liquid crystal layer, which is marked with a bold
line on the panel of FIG. 2 (e.g., see the thin quadrangular
waveform that represents a change of the applied data voltage.) For
example, even if the data voltage is instantly changed, it takes a
certain amount of time before the luminance level reaches a desired
level by changing the alignment direction of liquid crystals.
Further, a difference in data voltage applying time between a pixel
row to which the data voltage is firstly applied and a pixel row to
which the data voltage is last applied is generated in one
frame.
[0060] Therefore, because of the temporal difference, when the
image transferred to the left eye is displayed and thereafter, the
image transferred to the right eye may be immediately displayed in
the subsequent frame, even though the on/off state of the lenses of
the glasses 300 is changed and the image applied to the opposite
side can be perceived for some time. Therefore, the quality of
stereographic images may deteriorate between both eyes to
deteriorate the display quality of the 3D image. However, in at
least one embodiment of the present invention, the left eye
perceives the image transferred to the left eye and the black
image, and the right eye perceives the image transferred to the
right eye and the black image, by inserting the black data voltage
between the left data voltage and the right data voltage to
maintain a stereograph between both eyes as it is. As a result, the
display quality of the 3D image is improved.
[0061] As described above, in the exemplary embodiment of the
present invention, the black data voltage is inserted between the
left data voltage and the right data voltage. However, the black
data voltage may be a data voltage representing luminance higher
than black as well as a data voltage representing black. For
example, in alternate embodiments, a data voltage representing a
luminance higher than black is applied instead of the black data
voltage.
[0062] In FIGS. 1 and 2, by displaying the left-eye image or the
right-eye image for one frame and displaying the black image for
three frames, the number of frames to display the black image is
larger than that of frames to display the image (the left-eye image
or the right-eye image). Therefore, the left-eye image and the
right-eye image should be more clearly discriminated from each
other and the images should not be transferred to opposite eyes.
For example, the image designated for the left eye should not be
sent erroneously to right eye and vice versa. However, the
luminance is generally decreased.
[0063] An exemplary embodiment of the present invention will be
described with reference to FIGS. 3 to 6. FIG. 3 is a schematic
diagram showing an operation state of a 3 dimensional image display
device according to an exemplary embodiment of the present
invention and FIG. 4 is a graph showing a signal waveform of the 3D
image display device according to the exemplary embodiment of FIG.
3.
[0064] FIGS. 3 and 4 illustrate an embodiment where the number of
frames to display the black image is equal to that of frames to
display the image (the left-eye image or the right-eye image) by
displaying the left-eye image or the right-eye image for two frames
and displaying the black image for two frames.
[0065] In the exemplary embodiment of FIGS. 3 and 4, luminance is
more improved than the luminance in the exemplary embodiment of
FIGS. 1 and 2. Although a time to display the black is required
after the black data is applied to the last row on the liquid
crystal display panel (see the N+3 frame), there is a time up to
the N+4 frame in which the right-eye image is applied. Therefore,
crosstalk in which the left-eye image and the right-eye image are
wrongly transferred should not occur.
[0066] In the exemplary embodiment of FIGS. 3 and 4, timings when
the left lens and the right lens of the glasses are changed from
the on state to the off state coincide with the start of the N+3
frame and the start of the N+7 frame, respectively, but may be
positioned in the middle of the N+3 frame and the middle of the N+7
frame.
[0067] FIGS. 5 and 6 illustrate an embodiment of the present
invention. FIG. 5 is a schematic diagram showing an operation state
of a 3 dimensional image display device according to an exemplary
embodiment of the present invention and FIG. 6 is a graph showing a
signal waveform of the 3D image display device according to the
exemplary embodiment of FIG. 5.
[0068] In FIGS. 5 and 6, by displaying the left-eye image or the
right-eye image for three frames and displaying the black image for
one frame, the number of frames to display the black image is
smaller than that of frames to display the image (the left-eye
image or the right-eye image). Further, the timings when the left
lens and the right lens of the glasses are changed from the on
state to the off state coincide with the timings (the start timings
of the N+4 frame and the N+8 frame) when the right-eye image and
the left-eye image start to be input.
[0069] In the exemplary embodiment of FIGS. 5 and 6, luminance is
more improved than the luminance in the exemplary embodiment of
FIGS. 1 and 2 and the exemplary embodiment of FIGS. 3 and 4, but
crosstalk may occur. (See region C of FIG. 6)
[0070] Referring to the N+4 frame of FIG. 6, the right-eye image is
input on a first upper row of the liquid crystal display panel and
the black data is input on a last row with the start of the N+4
frame, but partial luminance of the left-eye image may be perceived
while the right-lens is on for a response time of the liquid
crystal display panel. For example, crosstalk may partially occur
to prevent the left-eye image and the right-eye image from being
clearly discriminated from each other.
[0071] However, a predetermined time interval is present between
actual frames to prevent the left-eye image from being completely
viewed for the corresponding interval and prevent the left-eye
image from being perceived by the right eye by delaying the on
timing of the right lens. For example, during the interval in which
the left-eye image and the right-eye image are overlapped with each
other, both lenses of the glasses are in the off state to remove
the crosstalk.
[0072] In the exemplary embodiment of FIGS. 5 and 6, luminance is
more improved than the luminance in other exemplary embodiments,
but crosstalk may partially occur. Therefore, the exemplary
embodiment may be adjusted to prevent crosstalk from occurring as
discussed above or when the intensity of the crosstalk is small,
even though the crosstalk partially occurs as shown in FIG. 6, the
exemplary embodiment may be used as it is. For example, when the
embodiment of FIG. 6 is used as it is, since the intensity of the
crosstalk actually sensed is small and the degree of improvement of
the luminance is large, there may be little or no problem
perceiving the 3D image.
[0073] As described in the exemplary embodiments of FIGS. 1 to 6,
four frames are allocated to the left-eye image and the black image
and four frames are allocated to the right-eye image and the black
image with high-speed driving (e.g., at 480 Hz). Application rates
of four frames with respect to the left-eye image and the black
image are adjusted, and as a result, the 3D image is displayed by
alternately turning on/off the left lens and the right lens of the
glasses.
[0074] Since the left-eye image and the right-eye image are
displayed for a longer time in the exemplary embodiment of FIGS. 3
and 4 than in the exemplary embodiment of FIGS. 1 and 2, and longer
in the exemplary embodiment of FIGS. 5 and 6 than in the exemplary
embodiment in FIGS. 3 and 4, each subsequent embodiment further
improves the luminance. However, in the exemplary embodiment of
FIGS. 5 and 6, crosstalk may occur.
[0075] As described in the exemplary embodiments of FIGS. 1 to 6,
the black image is inserted to discriminate the left-eye image and
the right-eye image from each other, but since the black image is
inserted, the luminance which can be displayed is reduced on the
whole.
[0076] However, in alternate embodiment of the invention, the
display luminance may be improved as described below.
[0077] FIGS. 7 to 13 are graphs showing a method of improving
luminance displayed by a 3D image display device according to an
exemplary embodiment of the present invention.
[0078] In an exemplary embodiment of the present invention,
additional luminance is used to display a luminance higher than the
luminance displayed by the input image data (left-eye image data
and right-eye image data).
[0079] The exemplary embodiments of FIGS. 7 to 13 will be described
based on the exemplary embodiment in which the left-eye image and
the right-eye image is displayed for two frames among a total four
frames as described in FIGS. 3 and 4. However, this embodiment may
also be applied to the exemplary embodiment of FIGS. 1 and 2 or the
exemplary embodiment of FIGS. 5 and 6.
[0080] Referring to FIG. 7, an additional luminance Lb1 is
additionally displayed only in the display luminance Li of the
left-eye or right-eye image displayed in the N frame, which is the
first frame among the N frame to N+3 frame.
[0081] For example, in the exemplary embodiment in which the same
luminance Li is displayed by displaying the image in the first and
second frames among a total four frames and no luminance is
displayed by displaying the black image in the third and fourth
frames, the additional luminance Lb1 is applied to the luminance
displayed in the first frame to improve the luminance displayed on
the display panel on the whole.
[0082] The intensity or degree of the additional luminance Lb1 may
vary and a method of determining the intensity or degree of the
additional luminance will be described below with reference to
FIGS. 14 to 20.
[0083] Further, in FIG. 7, the display luminance Li of the left-eye
or right-eye image is 50% of displayable luminance and the
luminance adding the additional luminance Lb1 is 100% of the
displayable luminance, but they may have various values in some
exemplary embodiments.
[0084] In the exemplary embodiment of FIG. 8, an additional
luminance Lb2 is displayed in the third frame unlike the exemplary
embodiment of FIG. 7. In FIG. 8, the luminance displayed by the
left-eye or right-eye image is 100% (Lim: maximum luminance) of the
displayable luminance in the first and second frames, but is not
necessarily limited thereto. For example, as shown in FIG. 8, since
the additional luminance Lb2 cannot be added in the first and
second frames, the additional luminance Lb2 may be applied in the
third frame. However, even when the displayed luminance of the
first and second frames is not at the maximum luminance, the
additional luminance Lb2 may be applied in the third frame.
[0085] However, in the exemplary embodiment of FIG. 8, crosstalk
may occur similarly as in the exemplary embodiment of FIGS. 5 and
6. Therefore, the additional luminance Lb2 may be applied by taking
care of the crosstalk.
[0086] FIGS. 9 and 10 illustrate an exemplary embodiment in which
the additional luminance Lb1 is separately displayed depending on
the display degree of the additional luminance Lb1 displayed in
accordance with the exemplary embodiment of FIG. 7.
[0087] An additional luminance Lb1a of FIG. 9 has a luminance
comparatively higher than an additional luminance Lb1b of FIG. 10
and is applicable where the luminance of the display device needs
to be more greatly improved. FIG. 10 is applicable when it is
enough to merely add a comparatively lower luminance. As shown in
FIGS. 9 and 10, the intensity of the additional luminance Lb1 is
adjustable and it will be described with respect to FIGS. 14 to
20.
[0088] FIGS. 11 and 12 illustrate an exemplary embodiment in which
the additional luminance Lb2 is separately displayed depending on
the display degree of the additional luminance Lb2 applied in
accordance with the exemplary embodiment of FIG. 8.
[0089] An additional luminance Lb2a of FIG. 11 has a luminance
comparatively higher than additional luminance Lb2b of FIG. 12 and
is applicable where the luminance of the display device needs to be
more greatly improved. FIG. 12 is applicable when it is enough to
merely add a comparatively lower luminance. As shown in FIGS. 11
and 12, the intensity of the additional luminance Lb2 is adjustable
and it will be described with reference to FIGS. 14 to 20.
[0090] A threshold is shown in FIGS. 11 and 12. The threshold is a
value which may be determined to maintain the luminance of the N+2
frame at an optimum level by considering crosstalk and the
improvement degree of the luminance. FIG. 11 illustrates a driving
scheme that favors improving the luminance using a higher threshold
than FIG. 12 and FIG. 12 illustrates a driving scheme that favors
reducing or entirely removing crosstalk over an improvement of the
luminance.
[0091] FIG. 13A illustrates an exemplary embodiment in which an
additional luminance Lbt is provided only in the first frame like
the exemplary embodiment of FIG. 7. When the intensity to be
applied to the additional luminance Lbt is determined as shown in
FIG. 13A, the additional luminance may be separately provided to
the first frame and the second frame as shown in FIGS. 13B and
13C.
[0092] In FIG. 13B, an exemplary embodiment is shown in which
additional luminances Lbt1 and Lbt2 are provided to the first frame
and the second frame, that are respectively different from each
other. In FIG. 13C, an exemplary embodiment is shown in which
additional luminances Lbt1' and Lbt2' are provided to the first
frame and the second frame, that respectively have the same
intensity.
[0093] In exemplary embodiments of the present invention, different
additional luminances may be provided to both frames like FIG. 13B
or the same additional luminance may be provided to both frames
like FIG. 13C, which will be described with reference to FIGS. 14
to 20.
[0094] FIGS. 14 to 18 illustrate a 3D image processor that
processes image data according to an exemplary embodiment of the
present invention. FIGS. 14 to 20 are diagrams showing the 3D image
processor of the 3D image display device according to an exemplary
embodiment of the present invention. FIG. 14 is a diagram showing
the overall structure of the 3D image processor.
[0095] Referring to FIG. 14, the 3D image processor 1000 includes a
gamma converter 100, a luminance improver 200, a reverse gamma
converter 300, and further includes a luminance improvement rate
provider 210 and a balance rate provider 220 adjusting the degree
of luminance improvement in the luminance improver 200.
[0096] The gamma converter 100 of the 3D image processor 1000 will
be described with reference to FIGS. 15 and 16. As shown in FIG.
15, image data (left-eye image data or right-eye image data) input
into the 3D image processor 1000 is converted into a value
depending on a gamma curve of the display device. As shown in FIG.
15, the input image data has a continuous value depending on a
gray, but the image data converted by the gamma converter 100 has a
discontinuous value depending on the gray and a bit number thereof
is also increased. For example, in the exemplary embodiment of FIG.
15, the input image data is data of 8 bits and the data outputted
from the gamma converter 100 is data of 12 bits. However,
embodiments of the invention are not limited thereto as the input
image data may be smaller or larger than 8 bits and the output
image data may be smaller or larger than 12 bits. The output image
data is generally bigger than the input image data because a wider
range is required since the bit count of the image data is
discontinuously varied depending on the gray by the gamma
curve.
[0097] In FIG. 16, an operation of the gamma converter 100 is shown
in more detail. For example, input image data is provided with
respect to red, green, and blue, respectively and the input image
data of each color is converted through a lookup table (LUT) of
stored corresponding colors. According to an exemplary embodiment,
when red 8-bit input image data is input, a value corresponding to
the data is found in the red lookup table LUT.sub.R and output.
When this occurs, the output value has 12 bits. 12-bit output
values corresponding to green and blue 8-bit input image data are
also found and outputted from lookup tables LUT.sub.G and
LUT.sub.B. A lookup table (LUT) may output a value which is stored
in a memory and corresponds to the input.
[0098] The luminance of the image data gamma-converted through such
a method is improved in the luminance improver 200, which will be
discussed below with reference to FIGS. 17 to 19. FIG. 17
illustrates the luminance improver 200 according to the exemplary
embodiment of the present invention.
[0099] Gamma-converted image data Lr, Lg, and Lb corresponding to
red, green, and blue are input into a luminance improvement data
generator 260 to generate display luminance data LrN, LrN+1, and
LrN+2 for three frames among four frames in which the left-eye
image (alternatively, right-eye image) and a black image are
displayed. In an exemplary embodiment, since displaying the black
image is determined in the N+3 frame, only luminance data up to the
N+2 frame is calculated, but even luminance data of the N+3 frame
may be generated in some exemplary embodiments.
[0100] As such, luminance data (including black data of the N+3
frame) generated with respect to four frames are stored in a frame
memory 250 with respect to red, green, and blue. The frame memory
250 operates in accordance with a clock of 4.times. speed to store
all luminance data output from the luminance improvement data
generator 260 and output it as output data OL. While FIG. 17
illustrates a clock of a 4.times. speed, embodiments of the present
invention are not limited to any particular clock speed. In FIG.
17, r, g, and b represent red, green, and blue, respectively.
[0101] In FIGS. 18 and 19, the method of generating the luminance
data with respect to four frames in the luminance improvement data
generator 260 is shown in more detail.
[0102] FIG. 18 is a diagram primarily showing the luminance
improvement data generator 260 for red in FIG. 17. The luminance
data of each frame is generated by a method of FIG. 19 based on a
luminance improvement rate (MBTR) provided from the luminance
improvement rate provider 210.
[0103] Whether one group of luminances or another group of
luminances is to be applied to the frames is established by
Equation 1 as follows:
L*(MBTR+1)<Max L(10.sup.12) [Equation 1]
where L represents the luminance data input into the luminance
improvement data generator 260, MBTR represents the max boost up
threshold rate, and Max L(10.sup.12) represents a maximum
displayable luminance.
[0104] For example, by using Equation 1, it can be determined
whether the sum of the luminance represented by the input luminance
data and luminance improved as high as the max boost up threshold
rate is smaller than the maximum displayable luminance.
[0105] If the result is true (Y), the luminance data of four frames
is determined on the basis of Equation 2 shown below.
LN<=L*(MBTR+1)
LN+1<=L*(MBTR+1)
LN+2<=0 [Equation 2]
[0106] However, if the result is false (N), the luminance data of
four frames is determined on the basis of Equation 3 below.
LN<=MAX L
LN+1<=MAX L
LN+2<={L*(MBTR+1)-MAX L}*2 [Equation 3]
[0107] In Equation 2 and Equation 3, LN, LN+1, and LN+2 represent
the luminance data of the N frame, the luminance data of the N+1
frame, and the luminance data of the N+2 frame, respectively and
since the luminance data of the N+3 frame is the black data, it is
not shown through the equations.
[0108] The luminance data of four frames generated as above are
stored in the memory frame 250 of FIG. 17 and thereafter, output.
The output data are input into the reverse gamma converter 300.
[0109] FIG. 20 illustrates an exemplary embodiment of the reverse
gamma converter 300. In FIG. 20, 12-bit data is converted into
8-bit data by performing the process in a reverse order to the
process of FIG. 15. For example, 12-bit luminance data based on the
gamma curve is converted into 8-bit linear data. A reverse gamma
conversion may also be performed by a lookup table (not shown) in
some exemplary embodiments. As discussed above, the data is not
limited to any particular bit size as the data input to the reverse
gamma converter 300 could be less or greater than 12 bits.
Similarly, the data output by the converter 300 could be less than
or greater than 8 bits. The converted 8-bit data is applied to each
pixel as a data voltage through a data driver (not shown) to
display the improved luminance.
[0110] The 3D image display device according to an exemplary
embodiment should have improved luminance as shown in FIG. 21. FIG.
21 is a graph showing the improved luminance of the 3D image
display device according to an exemplary embodiment of the present
invention.
[0111] In FIG. 21, 50% is applied as the luminance improvement rate
(MBTR), and as a result, the luminance depending on the gray
increases in the direction of the arrow. In particular, a section X
of the improved luminance curve from a gray corresponding to
luminance of 100 to a gray having luminance higher than 100
corresponds to an improved luminance amount acquired by improving
the luminance according to the present invention. Since this part
in the luminance curve corresponds to an embodiment of the
luminance which is larger than the maximum luminance that can be
displayed in the N frame and the N+1 frame, it corresponds to a
luminance improvement amount acquired while displaying a luminance
other than black in the N+2 frame.
[0112] The balance rate provider 220 provides a balance rate for
determining that a higher additional luminance will be applied to
any frame (see FIG. 13B) or the same additional luminance is
separately applied to all the frames (see FIG. 13C) in an example
of separately adding the luminance to two or more frames as shown
in FIGS. 13B and 13C at the time of providing the additional
luminance.
[0113] The luminance improvement rate provider 210 and the balance
rate provider 220 store a plurality of determined values depending
on display characteristics and may provide an appropriate rate to
the luminance improver 200 or allow adjustment of the rate in
accordance with a user's selection.
[0114] The 3D image processor 1000 may be provided in a signal
controller controlling the display panel or provided as an
additional external circuit in some exemplary embodiments.
[0115] Having described exemplary embodiments of the invention, 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 disclosure.
* * * * *