U.S. patent application number 13/703631 was filed with the patent office on 2014-04-03 for driving method of lcd device and driving system.
This patent application is currently assigned to SHENZHEN CHINA STAR OPTOELECTRONICS TECHNOLOGY CO., LTD.. The applicant listed for this patent is SHENZHEN CHINA STAR OPTOELECTRONICS TECHNOLOGY CO., LTD. Invention is credited to Yinhung Chen, Yuyeh Chen, Liangchan Liao.
Application Number | 20140092081 13/703631 |
Document ID | / |
Family ID | 50384703 |
Filed Date | 2014-04-03 |
United States Patent
Application |
20140092081 |
Kind Code |
A1 |
Liao; Liangchan ; et
al. |
April 3, 2014 |
DRIVING METHOD OF LCD DEVICE AND DRIVING SYSTEM
Abstract
A driving method of a liquid crystal display (LCD) device
includes a step A and a step B. In the step A, using frequency
conversion on a received source image signal when a type of the
received source image signal is different from a preset target
frequency, and converting a display frequency of the received
source image signal into a target frequency, generating a target
image signal based on the target frequency. In the step B,
performing an overvoltage drive output using an overvoltage driving
table matching with the target frequency of the target image
signal.
Inventors: |
Liao; Liangchan; (Shenzhen,
CN) ; Chen; Yuyeh; (Shenzhen, CN) ; Chen;
Yinhung; (Shenzhen, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHENZHEN CHINA STAR OPTOELECTRONICS TECHNOLOGY CO., LTD |
Shenzhen |
|
CN |
|
|
Assignee: |
SHENZHEN CHINA STAR OPTOELECTRONICS
TECHNOLOGY CO., LTD.
Shenzhen
CN
|
Family ID: |
50384703 |
Appl. No.: |
13/703631 |
Filed: |
October 29, 2012 |
PCT Filed: |
October 29, 2012 |
PCT NO: |
PCT/CN2012/083642 |
371 Date: |
December 12, 2012 |
Current U.S.
Class: |
345/213 ;
345/87 |
Current CPC
Class: |
G09G 3/3696 20130101;
G09G 2340/0435 20130101; G09G 2320/0252 20130101; G09G 3/3611
20130101; G09G 2310/0248 20130101 |
Class at
Publication: |
345/213 ;
345/87 |
International
Class: |
G09G 3/36 20060101
G09G003/36 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2012 |
CN |
201210371704.0 |
Claims
1. A driving method of a liquid crystal display (LCD) device,
comprising: A: using frequency conversion on a received source
image signal when a type of the received source image signal is
different from a preset target frequency, and converting a display
frequency of the received source image signal into a target
frequency of 65 Hz, generating a target image signal based on the
target frequency of 65 Hz; and B: performing an overvoltage drive
output using an overvoltage driving table matching with the target
frequency of the target image signal; in the step A, if frequency
of the received source image signal is lower than the target
frequency, generating a new frame picture, evenly inserting the new
frame pictures among frame pictures of the source image signal in a
frequency cycle to generate a new image signal, wherein a frequency
of the new image signal being same as the target frequency; if the
frequency of the source image signal is greater than the target
frequency, selecting partial pictures from the source image signal,
and discarding the selected partial pictures, wherein the selected
discarded partial pictures are evenly extracted from the frame
pictures of the source image signal in one frequency cycle of the
source image signal.
2. A driving method of a liquid crystal display (LCD) device,
comprising: A: using frequency conversion on a received source
image signal when a type of the received source image signal is
different from a preset target frequency, and converting a display
frequency of the received source image signal into a target
frequency, generating a target image signal based on the target
frequency; and B: performing an overvoltage drive output using an
overvoltage driving table matching with the target frequency of the
target image signal.
3. The driving method of the liquid crystal display (LCD) device of
claim 2, wherein the target frequency is greater than 45 Hz.
4. The driving method of the liquid crystal display (LCD) device of
claim 3, wherein the target frequency is greater than 60 Hz.
5. The driving method of the liquid crystal display (LCD) device of
claim 4, wherein the target frequency is 65 Hz.
6. The driving method of the liquid crystal display (LCD) device of
claim 2, wherein in the step A, if frequency of the received source
image signal is lower than the target frequency, generating a new
frame picture, and inserting the new picture into the source image
signal to generate a new image signal, wherein a frequency of the
new image signal being same as the target frequency.
7. The driving method of the liquid crystal display (LCD) device of
claim 6, wherein in the step A, the new frame pictures are evenly
inserted among frame pictures of the source image signal in one
frequency cycle of the source image signal.
8. The driving method of the liquid crystal display (LCD) device of
claim 6, wherein the new frame pictures inserted into the source
image signal are a totally black picture, a totally white picture,
an action detection compensation picture generated by computation,
a previous-frame picture, or a next-frame picture.
9. The driving method of the liquid crystal display (LCD) device of
claim 2, wherein in the step A, if frequency of the source image
signal is greater than the target frequency, selecting partial
pictures from the source image signal, and discarding the selected
partial pictures.
10. The driving method of the liquid crystal display (LCD) device
of claim 9, wherein in the step A, the selected discarded partial
pictures are evenly extracted from the frame pictures of the source
image signal in one frequency cycle.
11. A driving system of a liquid crystal display (LCD) device,
comprising: a conversion module converting a source image signal
having a different frequency from a target frequency into a preset
target frequency, wherein the driving system of the LCD device uses
one overvoltage driving table matching with the target
frequency.
12. The driving system of the liquid crystal display (LCD) device
of claim 11, wherein the conversion module comprises a buffering
module and a picture compensation module connected with the
buffering module.
13. The driving system of the liquid crystal display (LCD) device
of claim 12, wherein the buffering module is configured with a
buffer controller of two pictures, a buffering memory connected
with the buffer controller, and a fixed frequency clock.
14. The driving system of the liquid crystal display (LCD) device
of claim 12, wherein the compensation module comprises a
compensator, a static buffering memory connected with the
compensator, a buffer, a compensation picture counter, and a data
output port respectively connected with the buffer, the
compensator, and the compensation picture counter.
15. The driving system of the liquid crystal display (LCD) device
of claim 11, wherein the driving system further comprises an image
signal determination module determining a type of the source image
signal.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to the field of liquid
crystal displays (LCDs), and more particularly to a driving method
of an LCD device and a driving system.
BACKGROUND
[0002] Because liquid crystal display (LCD) devices have low energy
consumption and a small volume, they are widely welcomed by
consumers.
[0003] Because deflection reaction speed of liquid crystals (LCs)
of the LCD devices is not high enough, display effect of the LCD
devices may not be optimum, so an overvoltage drive is used to
accelerate reaction speed of the LCs. In the overvoltage drive, an
additional voltage load is decided by a previous image state and a
current image state of the LCD device. A voltage of overvoltage
drive is decided by a last pixel in a previous-frame image and a
first pixel in a current-frame image of the LCD device.
[0004] As gray scales of different pictures are different and the
voltages in the overvoltage drive are also different, an
overvoltage driving table is arranged in the LCD device to conform
to a corresponding overvoltage output and obtain an expected
picture gray scale. However, along with an input of source image
signals of different frequencies, using a three-dimension (3D)
shutter type LCD device as an example, output frequencies of image
signals are also changed. In this way, due to different output
frequencies, the overvoltage drive is inaccurate and a displayed
brightness curve (gamma curve) of the gray scales is poor, thus
increasing image crosstalk. If the overvoltage driving tables of
different frequencies are combined, more memory is used, which
increases costs, thus disadvantageous to controlling costs.
[0005] Certainly, when a two-dimensional (2D) image is displayed
and the input frequencies are different, as the overvoltage drive
is inaccurate, the displayed brightness curve of the gray scales is
also poor and the expected display effect may not be achieved.
SUMMARY
[0006] In view of the above-described problems, the aim of the
present disclosure is to provide a driving method of a liquid
crystal display (LCD) device and a driving system for reducing
crosstalk and saving costs.
[0007] The purpose of the present disclosure is achieved by the
following technical scheme: a driving method of an LCD device
comprises steps:
[0008] A: using frequency conversion on a received source image
signal when a type of the received source image signal is different
from a preset target frequency, and converting a display frequency
of the received source image signal into a target frequency of 65
Hz, generating a target image signal based on the target frequency
of 65 Hz; and
[0009] B: performing an overvoltage drive output using an
overvoltage driving table matching with the target frequency of the
target image signal;
[0010] in the step A,
[0011] if a frequency of the received source image signal is lower
than the target frequency, generating a new frame picture,
inserting evenly the new frame pictures among frame pictures of the
source image signal in a frequency cycle to generate a new image
signal, where a frequency of the new image signal being same as the
target frequency;
[0012] if the frequency of the source image signal is greater than
the target frequency, selecting partial pictures from the source
image signal, and discarding the selected partial pictures, wherein
the selected discarded partial pictures are evenly extracted from
the frame pictures of the source image signal in one frequency
cycle of the source image signal.
[0013] The purpose of the present disclosure can also be achieved
by the following technical scheme:
[0014] a driving method of an LCD device comprises steps:
[0015] A: using frequency conversion on a received source image
signal when a type of the received source image signal is different
from a preset target frequency, and converting a display frequency
of the received source image signal into a target frequency,
generating a target image signal based on the target frequency;
and
[0016] B: performing an overvoltage drive output using an
overvoltage driving table matching with the target frequency of the
target image signal.
[0017] In one example, the target frequency is greater than 45
Hz.
[0018] In one example, the target frequency is greater than 60 Hz.
As two commonly used frequency types in the prior art are 50 Hz and
60 Hz, the preferred target frequency is greater than 60 Hz. The
source image signal is not discarded to obtain a better effect when
viewing by human eyes.
[0019] In one example, the target frequency is 65 Hz. The preferred
target frequency is 65 Hz. As two commonly used frequency types in
the prior art are 50 Hz and 60 Hz, for 50 Hz, only 1 frame picture
is compensated for each three frames. For 60 Hz, only one frame
picture is added behind each 11 frames. For 65 Hz, a smaller
integer interval is used. To match the two main types, fewer
pictures are inserted. Only one picture compensation mode is
adopted, with simple design. Moreover, experimental data displays
that when the target frequency is selected as 65 Hz, better visual
effect can be achieved and human flash perception can be
reduced.
[0020] In one example, in the step A, if the frequency of the
received source image signal is lower than the target frequency,
generating a new frame picture, and inserting the new picture into
the source image signal to generate a new image signal, where a
frequency of the new image signal being same as the target
frequency. The frequency of the source image signal achieve the
target frequency adding new frame pictures, thus adapting to one
overvoltage driving table.
[0021] In one example, in the step A, the new frame pictures are
evenly inserted among frame pictures of the source image signal in
one frequency cycle of the source image signal. The evenly inserted
mode enables picture display to be smoother. Simple or complicated
compensation pictures are selected according to the number of the
frame pictures to be inserted, thus obtaining better display
effect.
[0022] In one example, the new frame pictures inserted into the
source image signal are a totally black picture, a totally white
picture, an action detection compensation picture generated by
computation, a previous-frame picture, or a next-frame picture.
Simple or complicated compensation pictures are selected according
to the number of the frame pictures to be inserted, thus obtaining
better display effect.
[0023] In one example, in the step A, if the frequency of the
source image signal is greater than the target frequency, selecting
partial pictures from the source image signal, and discarding the
selected partial pictures.
[0024] In one example, in the step A, the selected discarded
partial pictures are evenly extracted from the frame pictures of
the source image signal in one frequency cycle of the source image
signal.
[0025] A driving system of an LCD device is configured with a
conversion module converting a source image signal having a
different frequency from the target frequency into a preset target
frequency. The display device uses one overvoltage driving table
matching with the target frequency.
[0026] In the present disclosure, the source image signal having
the different frequency from the target frequency is converted into
the new image signal having the target frequency. In this way, the
LCD device only uses one overvoltage driving table to display the
image signals of different frequencies without causing a poor
brightness curve of gray scales, saving a lot of memory, which
saves the cost. For a three-dimensional (3D) display device,
different frequencies of a left-eye image signal and a right-eye
image signal are converted into the target frequency so as to share
one overvoltage driving table, which reduces flash and crosstalk.
For a two-dimensional (2D) display device, it is suitable to image
input of other frequencies, and the display achieves a better
display effect.
BRIEF DESCRIPTION OF FIGURES
[0027] FIG. 1 is a principle diagram of a driving method of a
liquid crystal display (LCD) device of the present disclosure;
[0028] FIG. 2 is a composition diagram of a driving system of a
liquid crystal display (LCD) device of the present disclosure;
[0029] FIG. 3 is a schematic diagram of conversion of a source
image signal and a system structure in a first example of the
present disclosure;
[0030] FIG. 4 is a schematic diagram of conversion of a left-eye
source image signal in a first example of the present
disclosure;
[0031] FIG. 5 is a schematic diagram of conversion of a right-eye
source image signal in a first example of the present
disclosure;
[0032] FIG. 6 is a signal fluctuation chart after converting an
image signal in a first example of the present disclosure;
[0033] FIG. 7 is a contrast diagram of visual perceptions of
signals of different frequencies; and
[0034] FIG. 8 is a composition diagram of a driving system of a
liquid crystal display (LCD) device in a third example of the
present disclosure.
DETAILED DESCRIPTION
[0035] The present disclosure is further described in detail in
accordance with the figures and the preferable examples.
[0036] As shown in FIG. 1, the present disclosure discloses a
driving method of a liquid crystal display (LCD) device, comprising
steps:
[0037] A: using frequency conversion on a received source image
signal when a type of the received source image signal is different
from a preset target frequency, and converting a display frequency
of the received source image signal into a target frequency,
generating a target image signal based on the target frequency;
and
[0038] B: performing an overvoltage drive output using an
overvoltage driving table matching with the target frequency of the
target image signal.
[0039] As shown in FIG. 2, the present disclosure also discloses a
driving system of an LCD device, comprising:
[0040] a conversion module 20 converting a source image signal,
where a frequency of the source image signal is different from a
target frequency, into a new image signal with a preset target
frequency; and
[0041] an overvoltage driving module 30 only using one overvoltage
driving table matching with the target frequency.
[0042] In the present disclosure, the source image signal having
the different frequency from the target frequency is converted into
the new image signal having the target frequency. In this way, the
LCD device only uses one overvoltage driving table to display the
image signals of different frequencies without causing a poor
brightness curve of gray scales, saving a lot of memory, which
saves costs. For a three-dimensional (3D) display device, different
frequencies of a left-eye image signal and a right-eye image signal
are converted into the target frequency so as to share one
overvoltage driving table, which reduces flash and crosstalk. For a
two-dimensional (2D) display device, it is suitable to image input
of other frequencies, and the display achieves a better display
effect.
[0043] For the step A, if the frequency of the received source
image signal is lower than the target frequency, generating a new
frame picture, and inserting the new frame picture into the source
image signal to generate a new image signal, where a frequency of
the new image signal being same as the target frequency.
[0044] For the step A, if the frequency of the source image signal
is greater than the target frequency, selecting partial pictures
from the source image signal, and discarding the selected partial
pictures.
[0045] According to the above driving method, the present
disclosure is further described by a specified example of the
driving system of the LCD device.
Example 1
[0046] As shown in FIG. 2, the driving system of the LCD device
comprises a conversion module 20 and an overvoltage driving module
30. As shown in FIG. 3, the conversion module comprises a buffering
module 21 and a compensation module 22. The buffering module 21 is
internally configured with a buffering controller of two pictures,
a buffer memory connected with the buffering controller, and a
fixed frequency clock. The compensation module 22 comprises a
compensator, a static buffering memory, a buffer, an X-frame
picture counter, and a data output port.
[0047] As shown in FIG. 3, the example is described by converting a
left-eye source image signal of a 3D shutter type display device of
60 Hz into a target image signal with the target frequency of 65
Hz. When the left-eye source image signal enters a buffering
controller of two pictures of the buffering module 21, the fixed
frequency clock is used to perform an action detection to a Nth
picture and a (N+1)th picture and store the two pictures into the
buffering memory. Then, the Nth picture and the (N+1)th picture are
simultaneously inputted into the compensator and the buffer of the
compensation module 22. A compensation picture X is generated in
the compensation module 22 and stored into the static buffering
memory. The pictures in the buffer are normally outputted. At this
moment, the X-frame picture counter is used to control the data
output port to control output of the compensation picture as needed
(inserting into the source image signal). At a moment (the moment
of inserting the compensation picture X, obtained by computation),
the compensation picture X is inserted between the Nth picture and
the (N+1)th picture and is outputted together with the Nth picture
and the (N+1)th picture. Each frame picture outputted is stored in
the picture memory by the overvoltage driving module 10 and is
contrasted with the overvoltage driving table for image output
control.
[0048] This is an example that the processed left-eye source image
signal of 60 Hz enters the overvoltage drive output. For a
right-eye source image signal of 50 Hz, the compensation mode is
the same. Certainly, the frequencies of the left-eye signal and the
right-eye signal are not limited to the numerical values cited in
the example.
[0049] In the example, the new frame picture inserted into the
source image signal, i.e. the compensation picture X, is a totally
black picture, a totally white picture, an action detection
compensation picture generated by computation, a previous-frame
picture, or a next-frame picture. If the number of the pictures to
be inserted is small, simple pictures, such as the totally black
picture, the totally white picture, the previous-frame picture, or
the next-frame picture can be selected. If the number of the
pictures to be inserted is large, the action detection compensation
picture generated by computation can be selected so as to obtain a
better display effect.
[0050] In the example, the number of compensation pictures X to be
inserted is selected according to a difference between the
frequency of the source image signal and the target frequency. The
insertion chance can be even, random, or in a given point. As shown
in FIG. 4, if the left-eye source image signal of 60 Hz is
converted into a new image signal of the target frequency of 65 Hz,
five-frame compensation pictures X are inserted. In the example, a
mode that new frame pictures are evenly inserted among the frame
pictures of the source image signal is used in one frequency cycle
of the source image signal, namely one compensation picture X is
inserted behind each eleven-frame picture of the source image
signal. As shown in FIG. 5, if the right-eye source image signal of
50 Hz is converted into the new image signal of the target
frequency of 65 Hz, fifteen-frame pictures are inserted. Thus, one
compensation picture X is inserted behind each 3-frame picture. The
evenly inserted mode enables picture display to be smoother. As
shown in FIG. 6, a movement curve after compensation slightly
shakes, but is not obvious under 3D view. As two commonly used
frequency type signals, 50 Hz and 60 Hz, are selected in the
example, and figures of 50 and 60 are a common divisor of 5, to
better evenly insert the matching compensation pictures, the target
frequency is a common divisor of 5 preferably. In the example, the
selected 65 Hz is just the common divisor of 5. Alternatively, the
target frequency can also be 55 Hz. However, two modes need to be
used to change the frequency of the source image signal into the
target frequency. One mode is to compensate the pictures, and the
other mode is to discard the pictures. Thus, design difficulty and
the cost are increased. For 65 Hz, a smaller integer interval is
selected, and only the mode to compensate the pictures is used.
Thus, there are fewer pictures to be inserted to match the two main
types. In addition, FIG. 7 shows a schematic diagram comparing
human flash perception to a brightness signal of a liquid crystal
display screen that is subject to fourier transform at different
frequencies. When the target frequency is selected at 65 Hz, the
data in the table shows that a better visual effect can be achieved
and human flash perception is reduced. Thus, in the example, the
selected target frequency is 65 Hz.
[0051] In the example, frame pictures are compensated to the source
image signal so as to achieve the target frequency corresponding to
the overvoltage driving module 30, so that the overvoltage driving
module 30 can correctly perform overvoltage drive. The target
frequency is larger than 45 Hz so that human eyes may not feel the
flash. Certainly, the target frequency is preferably larger than 60
Hz so that better effect is achieved when viewing by human
eyes.
Example 2
[0052] The difference between a first example and a second example
is that the left-eye source image signal is a sixty-frame signal
and the target frequency is 55 Hz. Thus, the processing mode of the
source image signal is to discard five-frame pictures so as to be
consistent with the target frequency. At this moment, the
five-frame pictures in the source image signal are removed by a
compensation module. Certainly, the removal mode is even extraction
from one frequency cycle of the source image signal, i.e.
sixty-frame pictures. Or, one frame picture is evenly extracted
every several pictures to be discarded. The right-eye signal has
the same processing mode, namely corresponding frame pictures are
added or reduced.
Example 3
[0053] The type of the source image signal and the frequency of
target image signal in the first example and the second example are
defined. Thus, signal determination is not needed.
[0054] For the example, a determination module of the image signals
is added, so that one overvoltage driving table needed to perform
drive output to different source image signals. As shown in FIG. 8,
the driving system of the LCD device comprises a determination
module 10, a conversion module 20, and an overvoltage driving
module 30. The driving process is shown as follows:
[0055] A: determining whether a type of a received source image
signal needs a frequency conversion, if yes, converting a display
frequency the received source image signal into the target
frequency, generating a target image signal based on the target
frequency. Otherwise, the source image signal is the target image
signal; and
[0056] B: performing an overvoltage drive output using an
overvoltage driving table matching with the target frequency of the
target image signal.
[0057] The present disclosure is described in detail in accordance
with the above contents with the specific exemplary examples.
However, this present disclosure is not limited to the specific
examples. For example, if the frequency of the source image picture
is consistent with the target frequency, no processing is required
in the compensation module. For the ordinary technical personnel of
the technical field of the present disclosure, on the premise of
keeping the conception of the present disclosure, the technical
personnel can also make simple deductions or replacements, and all
of which should be considered to belong to the protection scope of
the present disclosure.
* * * * *