U.S. patent application number 11/187822 was filed with the patent office on 2005-11-17 for image display system and image information transmission method.
Invention is credited to Hiyama, Ikuo, Inuzuka, Tatsuki, Kaneko, Yoshiyuki, Konno, Akitoyo, Mikami, Yoshiro, Toyoda, Yasutaka, Tsumura, Makoto, Yamamoto, Tsunenori.
Application Number | 20050253798 11/187822 |
Document ID | / |
Family ID | 18894597 |
Filed Date | 2005-11-17 |
United States Patent
Application |
20050253798 |
Kind Code |
A1 |
Hiyama, Ikuo ; et
al. |
November 17, 2005 |
Image display system and image information transmission method
Abstract
To provide a display device capable of displaying a moving
picture with high definition and at high speed. An image display
system includes: an image display unit; and a control unit. The
control unit has: a block discrimination circuit portion; an image
processing portion; a storage portion; and a synchronizing signal
generation portion. The block discrimination circuit portion
discriminates a moving picture or a still picture to process the
image information in accordance with the discriminated result, in
which the number of gradations for the image information processed
when the discriminated result is the moving picture is lower than
when the discriminated result is the still picture. Thereby, the
high definition image display and the high speed moving picture
display can be effected by reducing the information with lower
degree of recognition.
Inventors: |
Hiyama, Ikuo; (Hitachinaka,
JP) ; Yamamoto, Tsunenori; (Hitachi, JP) ;
Konno, Akitoyo; (Hitachi, JP) ; Tsumura, Makoto;
(Hitachi, JP) ; Kaneko, Yoshiyuki; (Hachioji,
JP) ; Mikami, Yoshiro; (Hitachiota, JP) ;
Inuzuka, Tatsuki; (Mito, JP) ; Toyoda, Yasutaka;
(Hitachi, JP) |
Correspondence
Address: |
MATTINGLY, STANGER, MALUR & BRUNDIDGE, P.C.
1800 DIAGONAL ROAD
SUITE 370
ALEXANDRIA
VA
22314
US
|
Family ID: |
18894597 |
Appl. No.: |
11/187822 |
Filed: |
July 25, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11187822 |
Jul 25, 2005 |
|
|
|
09961176 |
Sep 24, 2001 |
|
|
|
Current U.S.
Class: |
345/98 ;
375/E7.137; 375/E7.139; 375/E7.146; 375/E7.163; 375/E7.252 |
Current CPC
Class: |
G06F 3/14 20130101; H04N
19/137 20141101; H04N 19/124 20141101; G09G 2340/02 20130101; H04N
19/59 20141101; H04N 19/12 20141101; G09G 2340/0407 20130101; H04N
19/103 20141101 |
Class at
Publication: |
345/098 |
International
Class: |
H04N 005/14 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 7, 2001 |
JP |
2001-030374 |
Claims
What is claimed is:
1. An image display system having an image display unit composed of
a block having a plurality of pixels arranged like a matrix, with
said plurality of pixels divided in m pixel block units (m is a
natural number of 2 or greater), said m pixels being rewritten at a
time during one scanning interval, and a block in which said m
pixels are rewritten m or less times during m or less scanning
intervals, and an image control unit for transmitting said image
information to said image display unit, comprising: a graphic
control chip for processing said image information corresponding to
each pixel block unit with the information of block state appended,
and controlling a data transfer period corresponding to the state
of said image information, where said plurality of pixels are
divided into m pixel block units (m is a natural number of 2 or
greater); and a memory for storing the image information processed
by said graphic control chip.
2. An image display system having an image display unit composed of
a block having a plurality of pixels arranged like a matrix, with
said plurality of pixels divided into m pixel block units (m is a
natural number of 2 or greater), said m pixels being rewritten at a
time during one scanning interval, and a block in which said m
pixels are rewritten m or less times during m or less scanning
intervals, and an image control unit for transmitting said image
information to said image display unit, wherein said image control
unit comprises: a block state discrimination circuit for
discriminating a state of said image information corresponding to
one screen in a pixel block unit to append said state information
to said image information corresponding to said pixel block unit; a
graphic control chip for processing said image information
corresponding to each pixel block unit with the information of
state appended by said block state discrimination circuit, and
controlling a data transfer period corresponding to the state of
said image information; and a memory for storing the image
information processed by said graphic control chip, said memory
provided corresponding to said state discriminated by said block
state discrimination circuit.
3. An image display system, comprising: an image generation unit
for generating the image information; an image display unit
composed of a block having a plurality of pixels arranged like a
matrix, with said plurality of pixels divided into m pixel block
units (m is a natural number of 2 or greater), said m pixels being
rewritten at a time during one scanning interval, and a block in
which said m pixels are rewritten m or less times during m or less
scanning intervals; and an image control unit for transmitting said
image information to said image display unit, wherein; said image
information generation unit comprises a receiver for receiving an
image signal and a CPU for controlling said image signal received
by said receiver; and said image control unit comprises a graphic
control chip for processing said image information corresponding to
each pixel block unit with the information of block state appended,
and controlling a data transfer period corresponding to the state
of said image information, where said plurality of pixels are
divided into m pixel block units (m is a natural number of 2 or
greater), and a memory for storing the image information processed
by said graphic control chip.
4. An image display system, comprising: an image generation unit
for generating the image information; an image display unit
composed of a block having a plurality of pixels arranged like a
matrix, with said plurality of pixels divided into m pixel block
units (m is a natural number of 2 or greater), said m pixels being
rewritten at a time during one scanning interval, and a block in
which said m pixels are rewritten m or less times during m or less
scanning intervals; and an image control unit for transmitting said
image information to said image display unit, wherein; said image
information generation unit comprises a receiver for receiving an
image signal and a CPU for controlling said image signal received
by said receiver; and said image control unit comprises a block
state discrimination circuit for discriminating a state of said
image information corresponding to one screen in a pixel block unit
to append the information of said state to said image information
corresponding to said pixel block unit, a graphic control chip for
processing said image information corresponding to each pixel block
unit with the information of state appended by said block state
discrimination circuit, and controlling a data transfer period
corresponding to the state of said image information, and a memory
for storing the image information processed by said graphic control
chip, said memory provided corresponding to said state
discriminated by said block state discrimination circuit.
Description
[0001] The present application is a divisional application of
application Ser. No. 09/961,176, filed Sep. 24, 2001, the contents
of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an image display system,
and more particularly to an image information transmission method
in which the resolution, the number of gray scale level, and the
rewriting speed for the display are changeable within the
screen.
[0003] In recent years, an image display apparatus has become
thinner and lighter, a flat panel display such as a liquid crystal
display, a PDP (Plasma Display Panel), and an EL display
(Electroluminescent Display) has rapidly spread, in place of a CRT
that was mainly employed for the image display apparatus. Also, the
technical development of an FED (Field Emission Display) has also
rapidly progressed. Moreover, the display of high definition, high
speed moving picture has become requisite, along with the spread of
personal computers, DVD, and digital broadcasting. There will be an
increasing demand in the future for the higher performance of the
image display unit, and particularly, the display of high
definition, high speed moving picture. In particular, the liquid
crystal display has been greatly expected as a predominant entity
of the FPD.
[0004] Thus, a method of driving a TFT active matrix that is
typical of the conventional method of driving the liquid crystal
display will be described below. In driving the TFT active matrix
liquid crystal display, a line sequential scanning method is
employed, one scanning pulse being applied to each scanning
electrode once for each frame time period. One frame time period of
about 1/60 seconds is often used, and this pulse is usually applied
from the upper side of the panel to the lower side successively at
a shifted timing.
[0005] Accordingly, in a liquid crystal display unit having as many
as 1024.times.768 pixels, 768 gate wires are scanned within one
frame, so that the time width of scanning pulse is equal to about
22 .mu.s [=(1/60).times.(1/768)(seconds)].
[0006] On one hand, a liquid crystal driving voltage for driving a
liquid crystal with the pixels of one line to which a scanning
pulse is applied, is applied simultaneously to the signal
electrodes in synchronism with the scanning pulse. At a selected
pixel to which a gate pulse is applied, the gate electrode voltage
of a TFT connected to the scanning electrode is increased, so that
the TFT is placed in on state. At this time, the liquid crystal
driving voltage is is applied to a display electrode through the
source-to-drain of the TFT to charge a pixel capacitance composed
of a liquid crystal capacitance formed between the display
electrode and an opposite electrode formed on an opposite substrate
and a load capacitance in a pixel within a time period of 22 .mu.s
as previously mentioned. By repeating this operation, a liquid
crystal applied voltage is applied repetitively at every frame time
to the pixel capacitance over the entire face of panel.
[0007] Since the conventional TFT active matrix driving is
performed as in the above operation, the time width of scanning
pulse is shorter along with the higher definition and the
increasing number of pixels. Namely, it is required to charge the
pixel capacitance within a short time period. Also, to cope with
the high speed moving pictures, one frame time must be still
shortened, in which the time width of scanning pulse is also
shorter.
[0008] That is, with the conventional driving method for the image
display method or the image display unit, it is difficult to cope
with an increase in the display frequency that is caused by the
higher definition display, due to a signal delay on the wiring,
shortage of the writing time into each pixel, and increased
scanning frequency.
[0009] In a hold luminescence type image display unit such as a
liquid crystal display, when the moving picture is displayed, the
image quality may be degraded, as described in IEICE (The Institute
of Electronics, Information and Communication Engineers)
Transaction EID96-4, pp. 19-26 (1996-06). According to this report,
since there is inconsistency between a moving picture that is in
hold luminescent and the movement of the line of sight pursuing the
moving picture, some blur occurs in the moving picture, degrading
the display quality of moving picture. To improve the display
quality of moving picture, it was reported that there was a method
of providing n times the frame frequency. The method of providing n
times the frame frequency involves increasing the display frequency
in displaying the moving picture clearly on the hold luminescence
type image display unit such as the liquid crystal display.
However, with the driving method for the image display method or
the image display unit that is employed at present, as already
described, the increase in display frequency has approached its
upper limit.
[0010] In order to cope with the high definition display or moving
picture display for which there is increasing demand in the future,
new materials have been examined to reduce the wiring resistance or
wiring capacitance that is a factor of the signal delay on the
wiring. Also, to enhance the writing capability into the pixels,
instead of the conventional thin film transistor (TFT) using
amorphous silicone, the TFT using polysilicone has been put on the
market recently.
[0011] Moreover, in JP-A-08-006526 specification, there was
described a liquid crystal image display unit having means for
switching between one line selection and simultaneous selection of
plural lines to change the resolution.
[0012] However, with this technique, the resolution is constant on
the line. Also, there was no description for the method of
effecting both high definition and high speed display at the same
time. Further, in JP-A-09-329807 specification, there was described
a liquid crystal image display unit having block selecting means
for reducing the consumption power, in which the changed images are
only rewritten in a unit of block. However, the high speed moving
picture display is difficult to make due to the signal delay on the
is wiring and the limited writing capability, while displaying the
moving picture to be rewritten on the entire screen.
[0013] The image transmission from an image control unit (a
so-called graphics controller board) for effecting high definition,
high speed display to the image display unit is now considered. As
an example of the image display unit, taking the conventional
liquid crystal display having as many as 1024.times.768 pixels,
with eight bits for each color of red, green and blue (16 million
colors) and a frame frequency of 60 Hz, the bit rate is about 1.1
Gbps, which can not be transferred with one data line. Thus,
employing 24 data lines, for example, the data is transmitted to a
liquid crystal panel at a lower bit rate per line. Accordingly, the
image processing of the image control unit, and the transmission
between the image control unit and the image display unit become
difficult to make, along with the increased number of pixels and
the higher frequency corresponding to the high definition and high
speed display.
[0014] As described above, to make the high definition or high
speed moving picture display, it is required to charge the pixel
capacitance at a liquid crystal driving voltage within a short
time, and a driving method to treat the high definition and high
speed moving picture is needed. Further, since the image processing
of the image control unit, and the transmission between the image
control unit and the image display unit become difficult to make,
the driving method and the transmission method capable of
displaying the high definition, high speed moving picture that is
increasingly demanded in the future must be provided. Also, there
is a demand for the image driving method and the transmission
method with flexible procedures that can be employed directly even
though the wiring material or the capability of active elements is
enhanced.
[0015] According to the study of human eyes' visual
characteristics, when the moving picture is displayed, the image
quality can be sufficiently kept even if the definition or the
number of gray scale level is not too increased, because the moving
picture is being rewritten at high speed. On the other hand, when
the still picture is displayed, though there is no need for
rewriting at high speed, the high definition display is required to
recognize the image quality sufficient.
SUMMARY OF THE INVENTION
[0016] A first object of the present invention is to provide an
image transmission method conformable to the high definition image
display and high speed moving picture display at the same time,
making use of the visual characteristics of the human eyes for the
still picture display and the moving picture display, and reducing
the information with low degree of recognition.
[0017] A second object of the invention is to provide an image
transmission method conformable to the image display that can
switch between an area for rewriting the moving picture at high
speed and with lower definition and an area for rewriting the still
picture at low speed and with high definition, in order to
implement the high definition/high speed moving picture display,
making use of the visual characteristics of the human eyes for the
still picture display and the moving picture display.
[0018] A third object of the invention is to provide an image
display system consisting of an image generation unit, an image
control unit and an image display unit, and having an image
transmission method of transmitting the image between each unit in
which the high definition display and the high speed moving picture
display can be implemented at the same time.
[0019] In order to attain the above objects, according to the
present invention, there is provided an image information
transmission method of transmitting the image information from an
image control unit to an image display unit in a system consisting
of the image display unit having a plurality of pixels arranged
like a matrix to display the image information and the image
control unit for transmitting the image information to the image
display unit, wherein the image control unit processes the image
information in a pixel block unit with the information of a block
state appended in which the plurality of pixels are divided into m
pixel block units (m is a natural number of 2 or greater), and the
data transfer period is controlled in accordance with the state of
image information.
[0020] Also, according to the invention, there is provided an image
information transmission method of transmitting the image
information from an image control unit to an image display unit in
a system consisting of the image display unit having a plurality of
pixels arranged like a matrix to display the image information and
the image control unit for transmitting the image information to
the image display unit, wherein the image control unit has a block
state discrimination circuit for discriminating a state of image
information amounting to one screen in a pixel block unit to append
the information of the state to the image information corresponding
to the pixel block unit, and processes the image information
corresponding to each pixel block unit with the information of the
state appended by the block state discrimination circuit, whereby
the data transfer period is controlled in accordance with the state
of image information.
[0021] Further, the invention provides an image transmission method
of transmitting the image information in which the information of
block state is a moving picture state or a still picture state, and
the data transfer period for the still picture state controlled by
the image control unit is n times the data transfer period for the
moving picture state. Further, the invention provides the image
transmission method of transmitting the image information in which
the information of pixel block in the moving picture state is
compressed in terms of the number of gray scale level or the
resolution. Thereby, in the moving picture state, the image
information of one screen can be compressed, and transferred at
higher speed, while in the still picture state, the image
information of one screen can be transferred at lower frequency,
whereby the liquid crystal display unit can display consistently
the high speed moving picture and the high definition still
picture.
[0022] Further, the invention allows a clear moving picture to be
displayed without blur of the moving picture by transmitting the
information of pixel block that is in the moving picture state by
generating interpolated data between frames. Preferably, the
information of pixel block that is in the moving picture state is
transmitted at a compression ratio corresponding to the movement
speed of the image information, whereby in the still picture area,
a still picture can be displayed at high definition, and in the
high speed moving picture area, a clear moving picture can be
displayed. A slow speed moving picture can be displayed at higher
definition and clearly.
[0023] Also, according to the invention, there is provided an image
transmission method for use in an image display system having an
image generation unit for generating the image information, an
image control unit for converting the image information in
correspondence to an image display unit for displaying the image
information, and the image display unit for displaying an image
corresponding to the image data from the image control unit,
wherein the image data of one screen for the image display unit has
at least one of a moving picture area and a still picture area,
each area containing discrimination data indicating a moving
picture or a still picture, the moving picture data is compressed
into one n-th, in contrast to the still picture data, in terms of
at least one of the number of pixels or the number of gray scale
level, corresponding to the discrimination data, and the still
picture data is transmitted at a transfer period at least n times
faster than that of the moving picture data, whereby the image data
is transferred at an equal transfer rate for different picture
areas. In the compression of the image data, the image data is
compressed in a unit of m1.times.m2 pixels, and the display pixel
is preferably square or rectangular in a unit of 2.times.2,
2.times.1, 4.times.4, 4.times.2, 8.times.8, 8.times.4, or
8.times.2, for example. The liquid crystal display unit employs a
line sequential scanning method to compress the image in a unit of
rectangle, and define the scanning lines of the liquid crystal
display unit in a longitudinal direction, whereby the high
definition and high speed display can be effected to enable a
plurality of pixels to be written at the same time.
[0024] Also, the image control unit has a moving picture memory and
a still picture memory, and each image data is written beforehand
in each frame memory in accordance with the discrimination data, so
that the image data can be read and transferred at high rate.
[0025] Preferably, the image control device generates the n-times
speed movement correction data for the moving picture, and
transfers it to the image display unit, whereby the hold type
display unit can be enhanced in the image quality of moving
picture. Herein, the n-times speed data is preferably the data of
double speed, and more preferably the data of quadruple speed.
According to EID96-4, pp. 19-22 as previously mentioned, the
permissible limit of moving picture can be implemented with the
double speed display, and the sensing limit can be implemented with
the quadruple speed display.
[0026] Also, according to the movement speed of moving picture
area, when the high speed display is needed, the amount of image
data can be greatly reduced by image compression, and when the high
speed display is not needed, the image data is transferred at lower
image compression ratio to enable the display in accordance with
the movement speed of moving picture.
[0027] Preferably, the image data is efficiently transferred by
changing the image compression ratio in accordance with the size of
a display window in the moving picture area and the display
resolution. Further, the image data can be transferred efficiently
by compressing the image data in accordance with the number of gray
scale level and the display gradation ratio.
[0028] Also, this invention provides a broadcasting form for
transmitting the image information employing a transmission system
in which the image information has a moving picture flag and a
still picture flag in a unit of block of plural pixels, and
corresponding to the flag, the image information of one screen in a
still picture flag area is transmitted at a transmission frequency
equal to n time that of a moving picture flag area. Further, the
still picture and the moving picture divided in a unit of
transmission frequency is subjected to compression such as MPEG
that is a moving picture compression method, whereby the
compression ratio can be further increased, and the large
information can be transmitted through the small transmission
path.
[0029] Further, this invention provides a broadcasting system
employing the broadcasting form, in which by confirming beforehand
or in real time the number of display pixels or the display frame
frequency in an image system possessed by the user, the
broadcasting service rate is charged in accordance with the image
system. The transmission method of this invention allows the
transmission of the high definition still picture and the high
speed moving picture at high compression ratio. With the
conventional TV, the image is enjoyed at an ordinary definition
(NTSC), for example, the owner of the image system capable of the
high definition and high speed display is billed for additional
charge.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a block diagram showing one example of an image
display system according to the present invention.
[0031] FIG. 2 is a diagram showing one example of an image
compression method of the present invention.
[0032] FIG. 3 is a chart showing one example of a transmission
sequence of the present invention.
[0033] FIGS. 4A and 4B are diagrams showing one example of the
image compression method of the present invention.
[0034] FIG. 5 is a chart showing one example of transmission
sequence of the present invention.
[0035] FIG. 6 is a chart showing one example of transmission
sequence of the present invention.
[0036] FIG. 7 is a diagram showing one example of the image
compression method of the present invention.
[0037] FIG. 8 is a diagram showing one example of the image
compression method of the present invention.
[0038] FIG. 9 is a diagram showing one example of the image
compression method of the present invention.
[0039] FIG. 10 is a diagram showing one example of the image
compression method of the present invention.
[0040] FIG. 11 is a block diagram showing one example of an image
display method of the present invention.
[0041] FIG. 12 is a block diagram showing one example of a
broadcasting form of the present invention.
[0042] FIG. 13 is a circuit diagram showing one example of an image
display unit of the present invention.
[0043] FIG. 14 is a driving voltage waveform showing one example of
the image display unit of the present invention.
[0044] FIG. 15 is a circuit diagram showing one example of the
image display unit of the present invention.
[0045] FIG. 16 is a circuit diagram showing one example of the
image display unit of the present invention.
[0046] FIG. 17 is a circuit diagram showing one example of the
image display unit of the present invention.
[0047] FIG. 18 is a driving voltage waveform showing one example of
the image display unit of the present invention.
[0048] FIG. 19 is a level shift circuit diagram showing one example
of the image display unit of the present invention.
[0049] FIG. 20 is a block diagram showing one example of another
image display unit employing an image compression method of the
present invention.
[0050] FIG. 21 is a circuit diagram of another image display unit
employing the image compression method of the present
invention.
[0051] FIG. 22 is a circuit diagram of another image display unit
employing the image compression method of the present
invention.
DESCRIPTION OF THE EMBODIMENTS
[0052] The preferred embodiments of an image transmission method
and an image display system for use with the image transmission
method according to the present invention will be described below
by reference to FIGS. 1 to 22.
[0053] (Overall Configuration)
[0054] FIG. 1 is a block diagram showing the overall configuration
of the image display system of the present invention. The image
display system of an embodiment of the invention comprises an image
control unit 60 and an image display unit 70. Specific product
examples include televisions and personal computers. Of course,
other products are also available.
[0055] The image control unit 60 has a graphic control chip 61 and
a frame memory 62. For example, the image information from an image
generation unit 10 is passed through a bus 200 via an input
interface 200A, converted into a desired format of image data by
the graphic control chip 61, and transmitted through an output
cable 201 via an output interface 201A to the image display unit
70.
[0056] The image generation unit 10 has a CPU 11 and a receiver 12
for receiving the image information of a digital TV 100, a digital
camera 101, a scanner 102, a digital video camera 103, and the
Internet 104 from the outside, and sends or receives the image
information or commands through the bus 200 to or from the image
control unit 60. At this time, the image generation unit 10
preferably has a flag generation circuit 13 for generating a flag
of moving picture or still picture from the data format of each
image information. However, software may be used except for the
flag generation circuit 13. Also, the graphic control chip 61
comprises a clock generation circuit 61A, a synchronizing signal
generation circuit 61B, a compressed data generation circuit 61c
for each block, an address generation circuit 61D for block
compressed data, a block state discrimination circuit 61E, an
input/output interface 200A, 201A, and a frame memory 62 for
compressed data.
[0057] This invention involves discriminating a block state in m
pixel block units (m is a natural number of 2 or greater), and
changing the compression ratio or transmission frequency of data
from the image control unit 60 to the image display unit 70 in
accordance with the block state.
Embodiment 1
[0058] First of all, an image compression method according to an
embodiment of the present invention will be described below by
reference to FIG. 2. Herein, FIG. 2 shows an example of 4.times.4
pixels (m=16 pixels), in which the number within each pixel
indicates a gray scale level of pixel by 0 to 255 in the display
having 256 gradations. For example, when the original image data
500 is discriminated as the still picture in a unit of block by the
block state discrimination circuit 61E, the image conversion (16
image data) is not performed, like the still picture uncompressed
image data 510, because the definition is important for the still
picture, or the image compression is made with a smaller number of
gradations, without decreasing the definition, as will be described
later. On one hand, when the original image data 500 is
discriminated as the moving picture by the block state
discrimination circuit 61E, the resolution is reduced in a unit of
2.times.2 pixels, for example, and four image data 530 is
compressed, making use of the human eyes' visual sensation of not
sensing the image quality degraded due to reduced resolution or
smaller number of gradations, because the moving picture has
frequently changing images. Thereby, sixteen data can be compressed
into four.
[0059] An example of a transmission sequence of the image
information is shown in FIG. 3. The synchronizing signal generation
circuit 61B of FIG. 1 generates a moving picture vertical
synchronizing signal 400 and a still picture vertical synchronizing
signal 401 with a quadruple period, and further the block
discrimination circuit 61E generates a discrimination signal 410
from the image information for each block. In accordance with this
discrimination signal 410, the moving picture data 300 and the
still picture data 320 are transmitted. At this time, the still
picture data 320 corresponds to the still picture vertical
synchronizing signal 401, the data of one screen being transmitted
once per four moving picture vertical synchronizing signals 400.
Also, the moving picture data 300 is newly transmitted for every
moving picture vertical synchronizing signal 400. Then, if the
image data is transmitted at the equal resolution and the same
number of gradations, the moving picture data needs a quadruple
transmission rate.
[0060] Thus, it is required to transmit the image information
employing the image compression method as shown in FIG. 2, to
provide an transmission rate for the moving picture and the still
picture. The transmission of compressed data will be described
below by reference to FIGS. 4A and 4B. The moving picture or the
still picture is discriminated in a unit of block, depending on the
data of the block state discrimination circuit 61E of FIG. 1.
Reference numerals 500A to 500E denote the original images of still
picture, the original images 500A to 500E are invariable over time
because the still picture does not change. Reference numerals 501A
to 501E denote the original images of moving picture, which change
in every frame in accordance with the movement.
[0061] First of all, the transmission of still picture will be
described below. For the still picture, one pixel data within
2.times.2 pixels is transmitted in a first frame 510A, one pixel
data within 2.times.2 pixels that is different from that in the
first frame 510A is transmitted in a second frame 510B, and one
pixel data that is different is transmitted in a third frame 510C,
and then a fourth frame 510D, whereby the still picture is
produced.
[0062] On the other hand, for the moving picture, an average value
of 2.times.2 pixels is taken in the first frame 520A to transmit
the same data for four pixels, an average value of 2.times.2 pixels
is taken in the second frame 530B to transmit the same data for
four pixels because the image is moved, and an average value of
2.times.2 pixels is taken to transmit the same data for four pixels
in the third frame 530C and then the fourth frame 530D. In this
way, the moving picture and the still picture can be transmitted at
almost equal transmission rate. Accordingly, the high definition
display can be effected in the still picture area and the clear
moving picture display in the moving picture area.
Embodiment 2
[0063] Referring not to FIG. 5, a second embodiment in which the
transmission sequence of image information is different from that
of the embodiment 1 will be described below.
[0064] The synchronizing signal generation circuit 61B of FIG. 1
generates a moving picture vertical synchronizing signal 400 and a
still picture vertical synchronizing signal 401 with a quadruple
period, and further the block discrimination circuit 61E generates
a discrimination signal 410 from the image information for each
block. In accordance with this discrimination signal 410 having
three levels, the moving picture data 300, the slow speed moving
picture data 310 and the still picture data 320 are transmitted.
Herein, the slow speed moving picture data means the moving picture
with small movement, and is transmitted as an intermediate picture
between the moving picture and the still picture. As in FIG. 3, the
still picture data 320 corresponds to the still picture vertical
synchronizing signal 401, the data of one screen being transmitted
once per four moving picture vertical synchronizing signals 400.
Also, the moving picture data 300 is newly transmitted for every
moving picture vertical synchronizing signal 400. On the other
hand, the slow speed moving picture data 310 has the data of one
screen transmitted once per two moving picture vertical
synchronizing signals 400. Then, if the image data is transmitted
at the equal resolution and the same number of gradations, the
moving picture data needs a quadruple transmission rate. For this
reason, the moving picture data is compressed at half resolution,
as shown in FIG. 4, and the slow speed moving picture data is
compressed at half resolution in either longitudinal or transverse
direction to transmit the image information. Accordingly, the still
picture is displayed at high definition, the slow speed moving
picture is displayed clearly at high resolution, and the moving
picture is displayed clearly.
Embodiment 3
[0065] Referring not to FIG. 6, a third embodiment as the special
case in the transmission sequence of image information in the
embodiments 1 and 2 will be described below. In the embodiments 1
and 2, when the entire area of one screen is a moving picture area,
the moving picture data 300 is transmitted for every frame in
accordance with the moving picture vertical synchronizing signal
400 to display the moving picture on the entire area of screen.
Like the embodiments 1 and 2, the clear moving picture can be
displayed at half resolution at high speed. On one hand, when the
entire area of one screen is a still picture, the still picture
data 320 is transmitted for every frame in accordance with the
still picture vertical synchronizing signal 401 once per four
moving picture vertical synchronizing signals 400, to display the
still picture at high definition on the entire area of screen.
Embodiment 4
[0066] Referring to FIG. 7, a fourth embodiment of an image
compression method corresponding to a block discrimination signal
410 will be described below. If the original pixel image data 500
can be displayed on the image display unit 70, the still picture
uncompressed image data 510, like the original image data, is
transmitted in accordance with a sequence of FIG. 5 in the still
picture display area. Also, in the moving picture area, the
compressed image data 530 in which image information is compressed
into one-fourth (half resolution) is transmitted in accordance with
a sequence of FIG. 5. Further, in the slow speed moving picture
area, the compressed image data 520 having 2.times.2 pixels
compressed at two gradations is transmitted in accordance with a
sequence of FIG. 5.
[0067] Further, if the image compression is needed for the
transmission and the display on the image display unit, the
compressed image data 511 having 2.times.2 pixels compressed at
three gradations is transmitted for the still picture. If the image
compression is further needed, the compressed data 512 having
2.times.2 pixels compressed at two gradations is transmitted.
Thereby, a unit of block of 2.times.2 pixels can be transmitted in
two frames of the moving picture vertical synchronizing signal. In
transmission, the number of gradations is compressed, but the
resolution is not reduced.
Embodiment 5
[0068] Referring to FIG. 8, an embodiment 5 of an image compression
method in which the image is more compressed than in the embodiment
4 will be described below. This embodiment 5 is involved in a block
discrimination signal 410 to transmit the image data, like the
embodiments 1 and 2. In the previous embodiments, the image is
compressed in a unit of 2.times.2 pixels, but in the embodiment 5,
the image is compressed in a unit of 4.times.4 pixels. For the
still picture, the still picture compressed image data 513
approximated at four gradations in a unit of 4.times.4 pixels is
transmitted; for the slow speed moving picture, the compressed
image data 522 having 4.times.4 pixels approximated at arbitrary
two gradations is transmitted; and for the moving picture, the
moving picture compressed image data 531 having 4.times.4 pixels
approximated at two gradations, and further approximated at one
gradation in a unit of 2.times.2 pixels is transmitted. Employing
this compression, the transmission rate can be reduced. Also, the
still picture data with lower number of gradations but at high
definition, and the image data with lower number of gradations and
reduced resolution can be transmitted at high speed. When this
image data is displayed on the image display unit, it is possible
to display the clear moving picture at high speed and still picture
at high definition for the human vision.
Embodiment 6
[0069] Referring to FIG. 9, an embodiment 6 of the image
compression method in which the image is more compressed than in
the embodiment 5 will be described below. This embodiment 6 is
involved in the block discrimination signal 410 to transmit the
image data, like the embodiments 1 and 2. In the previous
embodiment 6, the image is discriminated in a unit of block of
8.times.4 pixels. When the original image data 500 is the still
picture, it is preferred that the uncompressed image data is
transmitted. If the number of pixels and the screen size become
larger, the transmission and the display may be difficult,
depending on the transmission rate and the display performance of
the image display unit. Thus, when the still picture is displayed,
the still picture compressed image data 515 approximated at four
gradations in a unit of 8.times.4 pixels is transmitted. Further,
the data compressed at two gradations is transmitted. Also, when
the moving picture is displayed, the image data has the 2.times.2
pixels compressed at one gradation, is compressed 532 at four
gradations in a unit of block of 8.times.4 pixels, and further
approximated 533 at two gradations, the thus image compressed data
is transmitted. Thereby, the compression efficiency of transmitting
the image can be enhanced.
Embodiment 7
[0070] Referring to FIG. 10, an embodiment 7 for generating the
image data corresponding to the moving picture will be described
below. Generally, the image data is transmitted at a frame
frequency of about 60 Hz, and the moving picture becomes unclear in
the hold type display, as set forth in the Prior Art. This, if the
original image data 500A, 500B is transmitted at a transmission
frequency of 60 Hz, the original image data is compressed into
one-fourth to produce the compressed image data 531A, 531B, which
is corrected for the movement by the amount of compressed image to
produce the corrected image data 532A, 533A and 534B which is then
transmitted. Thereby, the quadruple data transmission (at a
transmission frequency of 240 Hz) can be effected without
increasing the transmission rate. The original image data 500A,
500B can be equalized to produce the corrected image data, but it
is preferable to detect the acceleration of a moving image object
from several frames to produce the corrected image data. The
corrected image data is produced and transmitted to the image
display unit 70, where the clear moving picture can be
displayed.
Embodiment 8
[0071] Referring to FIG. 11, an embodiment 8 of an image display
system for displaying the image by producing the corrected data of
moving picture of the embodiment 7 will be described below. The
embodiment 8 is the image is control unit 60 of FIG. 1 in the
embodiment 1 that has a movement correcting n-times speed data
generation circuit 63, whereby the image in the moving picture area
is compressed at resolution with the discrimination data
discriminated for every block by the discrimination circuit 14, and
allocated to the n-times speed data. On one hand, the image in the
still picture area, designated by the discrimination data
discriminated by the discrimination circuit 14 is transmitted at
high definition by reducing the frame frequency but not decreasing
the resolution. Thereby, the moving picture or the still picture
can be transmitted at less increased transmission rate, whereby the
image display unit 70 can display the high definition still picture
and the clear moving picture.
[0072] Preferably, in accordance with the discrimination data, the
still picture data is held in a still picture memory 62A, and the
moving picture data is held in a moving picture memory 62B, whereby
the data can be written or read more simply. Namely, the compressed
image data of the moving picture or the still picture is held in
respective memory in the order of transmission, whereby the data
amount of image information can be reduced only by holding the
shape of the moving picture or still picture area and the
coordinates data.
Embodiment 9
[0073] Referring to FIG. 12, an embodiment 9 of a broadcasting form
using the embodiments 1 to 8 will be described below. A
broadcasting station 600 has a moving picture 601 taken by a TV
camera, and a still picture 602 picked up by a digital still camera
and CG, for example, in which respective image data are held in the
memories 601A and 602A, a picture 603 composed of the moving
picture and still picture is produced in accordance with the
purpose, the image data is compressed and arranged by the methods
of the embodiments 1 to 8, thereafter compressed in accordance with
the MPEG4 that is the compression form for broadcasting, and held
in a memory 606. In the memory 606, the data is described as a data
format at 605, and the image data is held in 604. This compressed
image data is provided wireless or by wire 610 to the consumer.
With the consumer, a receiver 12 receives the image information
wireless or by wire 611 from the broadcasting station, and a
decoder 15 decodes the compression method of the broadcasting form.
Thereafter, the image information is transmitted to the image
control unit 60, and then transmitted to the image display unit by
the methods of the embodiments 1 to 8. In the above broadcasting
form, the broadcasting station can register the hardware
environment of the consumer beforehand or in real time, and assess
the broadcasting service rate, when the consumer has the image
control unit for controlling in the embodiments 1 to 8 and the
image display unit for displaying the image. Also, for the consumer
having the conventional image control unit and image display unit,
the broadcasting station can register the hardware environment of
the consumer beforehand or in real time and assess the broadcasting
service rate that is different from the above service rate. The
user having the conventional image display system can not display
the moving picture and the still picture separately, and after the
received data is encoded, the image data in the moving picture area
is received at a period of 531A, 531B in FIG. 10, and the image
data in the still picture area, or the image data 510A, 510E in
FIG. 4, is received at the same period, whereby the moving picture
performance is degraded in a case of the hold type image display
unit with low definition. Therefore, the still picture and the
moving picture can be displayed in high image quality in the
broadcasting form of the embodiment 9.
Embodiment 10
[0074] Referring to FIGS. 13 to 19, an embodiment 10 of the image
display unit 70 for use in the image display system will be
described below.
[0075] FIG. 13 is an equivalent circuit diagram showing an example
of a pixel circuit configuration of the image display unit that can
display the moving picture area and the still picture area
separately according to the invention. The embodiment 10 has the
pixel circuit configuration having four pixels of 2.times.2 pixels
as one block, and a number of pixel circuits are arranged to form
an entire display area of the image display unit. Note that the
image display unit applied to the image display system of the
invention is not limited to the liquid crystal display, but is also
applicable to ELD, FED and PDP. In this embodiment 10 of the
invention, the liquid crystal display is exemplified as it is most
suitable.
[0076] The liquid crystal display of the embodiment 10 has a
lighting system on the back face, and comprises a pair of
transparent substrates having a polarizing plate and a liquid
crystal layer sandwiched between the pair of transparent
substrates, in which an electric field is applied to the liquid
crystal layer to control a polarized state of the liquid crystal
layer to display the image.
[0077] FIG. 13 shows one block of four pixels. Although all the
components of each pixel are not designated by numerals, each
numeral of component is suffixed with character A for the upper
left pixel, B for the upper right pixel, C for the lower left
pixel, and D for the lower right pixel, and further, the character
is suffixed with character R, G or B corresponding to red, green or
blue pixel. In the embodiment 10, one block is formed of four
pixels 50A, 50B, 50C and 50D, one pixel consisting of three
elements of red (50AR, 50BR, 50CR, 50DR), green (50AG, 50BG, 50CG,
50DG), and blue (50AG, 50BB, 50CG, 50DG). A scanning wire 20 common
to four pixels is formed centrally, and is connected to the gates
of twelve thin film transistors (24AR, 24BR, 24CB, 24DB) that are
the first switch. Also, a block selection signal wiring 21A is
connected to the drain electrodes of the thin film transistors
24AR, 24AG and 24AB that are the first switch; a block selection
signal wiring 21B is connected to the drain electrodes of the thin
film transistors 24BR, 24BG and 24BB; a block selection signal
wiring 21C is connected to the drain electrodes of the thin film
transistors 24CR, 24CG and 24CB; and a block selection signal
wiring 21D is connected to the drain electrodes of the thin film
transistors 24DR, 24DG and 24DB. Also, the source electrodes of the
thin film transistors that are the first switch are connected to
the gate electrodes of twelve thin film transistors (23AR, 23BR,
23CB, 23DB, etc.) that are the second switch. Further, a red image
signal wiring 22R, a green image signal wiring 22G and a blue image
signal wiring 22B are connected to the drain electrodes of the thin
film transistors that are the second switch; pixel electrodes are
connected to the source electrodes of the thin film transistors
that are the second switch, and connected via a liquid crystal
layer to the opposite electrodes (26AR, 26BR, 26CB, 26DB, etc.) to
form pixel portions (25AR, 25BR, 25CB, 25DB, etc.). Note that the
opposite electrodes are commonly used for all the pixels, with a
holding capacitor formed in parallel with the pixel portions (25AR,
25BR, 25CB, 25DB, etc.). With such a pixel configuration, the
display of separated image area is enabled in which the moving
picture area and the still picture area are separated.
[0078] Specifically, a driving voltage waveform that is applied to
each wire to display the image area separately is shown in FIG. 14.
Consider a scanning wire Y(j) at the j-th order. A gate voltage 30
for turning on the thin film transistors that are the first switch
is applied to the scanning wire Y(j) at every frame period 34. In
synchronism with this gate voltage 30, the voltages 32A to 32D are
applied to 21A to 21D that are block selecting signal wires
X(I).sub.1 to X(I).sub.4 in the still image display area at every
four frames in accordance with the discrimination signal 410, and
an image signal 31 corresponding to red D(I).sub.R, green
D(I).sub.G and blue D(I).sub.B is applied through the second switch
to the pixels in synchronism with this gate voltage 30.
Accordingly, any one of the pixels 50A, 50B, 50C and 50D is only
selected. For the pixels not selected, the voltage is held during
four frames. On one hand, in the moving picture display area, a
voltage 33 is applied to 21A to 21D that are block selecting signal
wires X(I).sub.a11 at every frame in accordance with the
discrimination signal 410, and an image signal 31 corresponding to
red D(I).sub.R, green D(I).sub.G and blue D(I).sub.B is applied
through the second switch to the pixels in synchronism with this
gate voltage 30. Accordingly, the same signal is applied to all of
the pixels 50A, 50B, 50C and 50D, whereby the same display for four
pixels can be rewritten for every frame. For a scanning wire Y(j)
at the j+1-th order, like the j-th scanning wire, whether the high
definition display area or the low definition display area is
discriminated, and the image area can be displayed separately by
inputting the driving waveform. Accordingly, if the still picture
is displayed in the high definition area, and the moving picture is
displayed in the low definition area, the moving picture can be
rewritten at high speed and the still picture displayed at high
definition or high density, even when the moving picture and the
still picture are mixed. As shown in FIG. 5, when the slow speed
moving picture is displayed, block selecting signal wires
X(I).sub.1 to X(I).sub.4 are selected in accordance with the
discrimination signal 410, whereby the slow speed moving picture
can be displayed in two frames.
[0079] Another example of the pixel circuit configuration for
displaying the image area separately is shown in FIG. 15. The
example involves the pixel circuit configuration having 2.times.2
pixels as one block, and a number of pixel circuits are arranged to
form an entire display area of the image display unit. Note that
one unit of block is not limited to four pixels. And the image
display unit with the image area separation display system of the
invention is not limited to the liquid crystal display, but is also
applicable to EL display, FED and PDP. In this example, the liquid
crystal display is exemplified as it is most suitable. In this
embodiment 10, the liquid crystal display of the embodiment 10 has
a lighting system on the back face, and comprises a pair of
transparent substrates having a polarizing plate and a liquid
crystal layer sandwiched between the pair of transparent
substrates, in which an electric field is applied to the liquid
crystal layer to control a polarized state of the liquid crystal
layer to display the image. In the embodiment 10, one block is
formed of four pixels 50A, 50B, 50C and 50D, one pixel consisting
of three elements of red (50AR, 50BR, 50CR, 50DR), green (50AG,
50BG, 50CG, 50DG), and blue (50AB, 50BB, 50CB, 50DB). FIG. 15 shows
four pixels. Although all the components of each pixel are not
designated by numerals, each numeral of component is suffixed with
character A for the upper left pixel, B for the upper right pixel,
C for the lower left pixel, and D for the lower right pixel, and
further, the character is suffixed with character R, G or B
corresponding to red, green or blue pixel. A scanning wire 20
common to four pixels is formed centrally, and is connected to the
gates of twelve thin film transistors (24AR, 24BR, 24CB, 24DB,
etc.) that are the first switch. Also, a block selection signal
wiring 21A is connected to the gate electrodes of the thin film
transistors 23AR, 23AG and 23AB that are the second switch; a block
selection signal wiring 21B is connected to the gate electrodes of
the thin film transistors 23BR, 23BG and 23BB; a block selection
signal wiring 21C is connected to the gate electrodes of the thin
film transistors 23CR, 23CG and 23CB; and a block selection signal
wiring 21D is connected to the gate electrodes of the thin film
transistors 23DR, 23DG and 23DB. Also, the electrodes (26AR, 26BR,
26CB, 26DB, etc.) are connected to the drain electrodes of the
second switch, and commonly used. A red image signal wiring 22R, a
green image signal wiring 22G and a blue image signal wiring 22B
are connected to the drain electrodes of the thin film transistors
that are the first switch, respectively, and the source electrodes
of the thin film transistors that are the first switch become pixel
electrodes, and the source electrodes of the thin film transistors
(23AR, 23BR, 23CB, 23DB, etc., twelve transistors) are formed with
opposite electrodes, a liquid crystal layer being sandwiched
between the pixel electrode and the opposite electrode to form the
pixel portions (25AR, 25BR, 25CB, 25DB, etc.). The pixel portions
(25AR, 25BR, 25CB, 25DB, etc.) have a holding capacitor disposed in
parallel. With such a pixel configuration, the display of separated
image area is enabled in which the moving picture area and the
still picture area are separated.
[0080] The driving voltage waveform that is applied to each wire to
display the image area separately is similar to that of FIG. 14.
Accordingly, if the still picture is displayed in the high
definition area, and the moving picture is displayed in the low
definition area, the moving picture can be rewritten at high speed
and the still picture displayed at high definition or high density,
even when the moving picture and the still picture are mixed.
[0081] Another example of the pixel circuit configuration for
displaying the image area separately is shown in FIG. 16. The
example involves the pixel circuit configuration having 2.times.2
pixels as one block, and a number of pixel circuits are arranged to
form an entire display area of the image display unit. Note that
one unit of block is not limited to four pixels, but considering
the decrease in opening ratio due to more wires, one block of four
pixels is preferable. And the image display unit with the image
area separation display system of the invention is not limited to
the liquid crystal display, but is also applicable to EL display,
FED and PDP. In this example, the liquid crystal display is
exemplified as it is most suitable. In this embodiment 10, the
liquid crystal display of the embodiment 10 has a lighting system
on the back face, and comprises a pair of transparent substrates
having a polarizing plate and a liquid crystal layer sandwiched
between the pair of transparent substrates, in which an electric
field is applied to the liquid crystal layer to control a polarized
state of the liquid crystal layer to display the image. In the
embodiment 10, one block is formed of four pixels 50A, 50B, 50C and
50D, one pixel consisting of three elements of red (50AR, 50BR,
50CR, 50DR), green (50A, 50BG, 50CG, 50DG), and blue (50AB, 50BB,
50CB, 50DB). FIG. 16 shows four pixels. Although all the components
of each pixel are not designated by is numerals, each numeral of
component is suffixed with character A for the upper left pixel, B
for the upper right pixel, C for the lower left pixel, and D for
the lower right pixel, and further, the character is suffixed with
character R, G or B corresponding to red, green or blue pixel. A
scanning wire 20 common to four pixels is formed centrally, and is
connected to the gates of twelve thin film transistors (24AR, 24BR,
24CB, 24DB, etc.) that are the first switch. Also, a red image
signal wiring 22R, a green image signal wiring 22G and a blue image
signal wiring 22B are connected to the drain electrodes of the thin
film transistors 24AR, 24AG and 24AB that are the first switch,
respectively. A block selection signal wiring 21A is connected to
the gate electrodes of the thin film transistors (23AR, 23AG, 23AB)
that are the second switch; a block selection signal wiring 21B is
connected to the gate electrodes of the thin film transistors
(23BR, 23BG, 23BB); a block selection signal wiring 21C is
connected to the gate electrodes of the thin film transistors
(23CR, 23CG, 23CB); and a block selection signal wiring 21D is
connected to the gate electrodes of the thin film transistors
(23DR, 23DG, 23DB). Also, the source electrodes of the thin film
transistors that are the first switch are connected to the drain
electrodes of the thin film transistors that are the second switch.
Further, the pixel electrodes are connected to the source
electrodes of the thin film transistors that are the second switch,
a liquid crystal layer being sandwiched between the pixel electrode
and the opposite electrode (26AR, 26BR, 26CB, 26DB, etc.) to form
the pixel portions (25AR, 25BR, 25CB, 25DB, etc.). Note that the
opposite electrodes (26AR, 26BR, 26CB, 26DB, etc.) are commonly
used for all the pixels. The pixel portions (25AR, 25BR, 25CB,
25DB, etc.) have a holding capacitor disposed in parallel. With
such a pixel configuration, the display of separated image area is
enabled.
[0082] The driving voltage waveform that is applied to each wire to
display the image area separately is similar to that of FIG. 14.
Accordingly, if the still picture is displayed in the high
definition area, and the moving picture is displayed in the low
definition area, the moving picture can be rewritten at high speed
and the still picture displayed at high definition or high density,
even when the moving picture and the still picture are mixed.
[0083] Another example of the pixel circuit configuration for
displaying the image area separately is shown in FIG. 17. The
example involves the pixel circuit configuration having 2.times.2
pixels as one block, and a number of pixel circuits are arranged to
form an entire display area of the image display unit. Note that
one unit of block is not limited to four pixels, but considering
the decrease in opening ratio due to more wires, one block of four
pixels is preferable. And the image display unit with the image
area separation display system of the invention is not limited to
the liquid crystal display, but is also applicable to EL display,
FED and PDP. In this example, the liquid crystal display is
exemplified as it is most suitable. In this embodiment 10, the
liquid crystal display of the embodiment 10 has a lighting system
on the back face, and comprises a pair of transparent substrates
having a polarizing plate and a liquid crystal layer sandwiched
between the pair of transparent substrates, in which an electric
field is applied to the liquid crystal layer to control a polarized
state of the liquid crystal layer to display the image. In the
embodiment 10, one block is formed of four pixels 50A, 50B, 50C and
50D, one pixel consisting of three elements of red (50AR, 50BR,
50CR, 50DR), green (50AG, 50BG, 50CG, 50DG), and blue (50AB, 50BB,
50CB, 50DB). A pixel structure is such that a scanning wire 40 is
connected to the gate electrode of the thin film transistors (41AR,
41AG, 41AB, etc.) that are the switch for every pixel. Also, a red
image signal wiring 43R, a green image signal wiring 43G and a blue
image signal wiring 43B are connected to the drain electrodes of
the thin film transistors 41, respectively. Also, the pixel
electrodes are connected to the source electrodes of the thin film
transistors 41, a liquid crystal layer being sandwiched between the
pixel electrode and the opposite electrode 44 to form the pixel
portions 42. Note that the opposite electrodes 44 are commonly used
for every two pixels in the transverse direction, and further for
every line, whereby two kinds of opposite electrodes 44A, 44B are
made up. With such a pixel configuration, the pixel structure can
be simplified as compared with those of the embodiments 1 to 3, and
the manufacturing process can be reduced in order to realize low
cost.
[0084] The driving voltage waveform that is applied to each wire to
display the image area separately is shown in FIG. 18. Consider Gi
and Gi+1 for the i-th and i+1-th scanning wires 40. A gate voltage
30A at two levels is applied to a scanning wire Gi at every frame
period 34, and a gate voltage 30B that is inversed from the gate
voltage 30A at two levels is applied to a scanning wire Gi+1 at the
same time. For the convenience of explanation, the area of a time
35 is made a high definition display area, and the area of a time
36 is made a low definition display area. Then, during the high
definition display time 35, the opposite electrode 44 is high at a
potential 37A, with an image signal 35A put high. The thin film
transistor 41 is kept from being turned on at a lower level of the
two levels of the gate voltages 30A, 30B, and the thin film
transistor 41 is only turned on at a higher level of the two levels
of the gate voltages 30A, 30B. Within 2.times.2 pixels (12 picture
elements), 6 picture elements are written and the remaining 6
picture elements are held. At the next frame, the voltage levels of
Gi and Gi+1 in the scanning wire 40 are inversed, the data of
picture elements written at the previous frame are held and the
data of picture elements held at the previous frame are rewritten.
On the other hand, during the low definition display time 36, the
opposite electrode 44 is low at a potential 37B, with an image
signal 36A put low. The thin film transistor 41 is turned on at two
levels of the gate voltages 30A, 30B. Within 2.times.2 pixels (12
picture elements), 12 picture elements are all written.
Accordingly, the image is composed of two frames in the high
definition area, while the image is rewritten at high speed for
every frame in the low definition area.
[0085] For the next scanning wires Gi+2 and Gi+3, the high
definition display area or the low definition display area is
discriminated, and the above driving waveform is entered, whereby
the image area can be displayed separately. Accordingly, if the
still picture is displayed in the high definition area, and the
moving picture is displayed in the low definition area, the moving
picture can be rewritten at high speed and the still picture
displayed at high definition or high density, even when the moving
picture and the still picture are mixed.
[0086] A circuit configuration in which the image signals 35A and
36A has the level of voltage shifted in the embodiment 10 is shown
in FIG. 19. First of all, the image data from the image control
unit is converted by a D/A converter 150, a high level signal 35A
or a low level signal 36A is selected in accordance with the
discrimination data for discriminating between the moving picture
and the still picture by a level shifter 151, and the signal is
applied through an amplifier 152 to the signal wiring 43. At this
time, in the case of the still picture display at high definition,
the high level signal 35A obtained by the level shifter 151 is
applied through the signal wiring 43 to one pixel 41 within the
block. At the next frame, the pixels written at this time are held,
and different pixels are written, whereby the high definition
display is enabled. In the case of the moving picture display at
low definition, the low level signal 36A obtained by the level
shifter 151 is applied through the signal wiring 43 to all the
pixels 41 within the block. Also, in the high definition area, one
pixel within one block is selected and displayed, but if the level
shifter 151 is arranged for every signal wiring 43, diagonal pixels
41A, 41D (similarly 41B, 41C) can be written at the same time.
Further, at the time of low definition display, if the level
shifter 151 is arranged for every signal wiring 43, a same signal
can be written into the pixels 41A and 41C, and a same signal that
is different from the previous same signal can be written into the
pixels 41B and 41D at the same time.
[0087] Accordingly, in the embodiment 10, the display with
different definitions is enabled by selecting arbitrary area for
every scanning line 40. Further, the pixel structure can be simply
made in the almost same manner as the conventional structure only
by dividing the opposite electrodes, whereby the image area
separation display system can be implemented. Also, with this
system, any area having two or more pixels and an integral multiple
of two pixels can be selected in the direction of the scanning line
40.
Embodiment 11
[0088] Referring to FIGS. 20 to 22, an embodiment 11 will be
described below in which the transmission system as explained in
the embodiment 1 is employed in other image display units. FIG. 20
is a block diagram showing the overall configuration of an image
display unit, in which each pixel has a transistor circuit portion
for controlling a switch connected to the liquid crystal layer to
be turned on or off in accordance with a summation of voltages
input from the X direction and the Y direction, and a signal supply
wiring commonly used in the series of pixels (four wires extending
from the signal supply circuit are commonly used in FIG. 20).
Thereby, this image display unit can process the pixels in a unit
of block, and display the pixels in a unit of block. The image
display unit and the transmission method will be set forth below. A
circuit configuration of each pixel is shown in FIGS. 21 and 22.
Note that a common wire connected to one electrode for carrying the
liquid crystal layer is commonly used for plural pixels (four
pixels in FIG. 20), whereby a plurality of lines can be controlled
at the same time.
[0089] Referring to FIG. 21, each pixel has an X signal line 707
for inputting a voltage from the X direction, a Y signal line 708
for inputting a voltage from the Y direction, an XY operation
circuit portion 714 for operating the voltages entered from the X
direction and the Y direction to output a signal, a signal
comparator 715 for controlling a pixel switch to be turned on or
off to regulate the orientation of the liquid crystal layer in
accordance with a signal of the XY operation circuit portion, and a
liquid crystal driving signal line 710 (common for plural columns
of pixels) for supplying a voltage to the liquid crystal layer.
FIG. 22 shows a specific circuit configuration and FIG. 21 shows
the configuration of transistors to implement this circuit
configuration. For more details of this image display unit, refer
to JP-A-2000-172940.
[0090] This image display unit can control the writing into the
liquid crystal is layer in accordance with the voltage values
entered from the X direction and the Y direction. Namely, a voltage
is applied to a desired number of X signal lines and Y signal lines
at a time and a plurality of pixels in the X direction and the Y
direction can be controlled for display. And the pixels can be
driven in a unit of pixel or in a unit of block by adjusting the
voltages entered from the X direction and the Y direction (i.e.,
calculating a combination of voltages in the X direction and the Y
direction for the signal comparator to issue an ON instruction of
the pixel switch (an instruction for writing liquid crystal driving
voltage) to a desired number of pixels alone). Since the signal
supply circuit is common to plural columns of pixels, the same
liquid crystal driving voltage can be applied at a time to plural
pixels selected. Thereby, the faster display than by the ordinary
line scanning, viz., the transmission of compressed image and its
display in a unit of block as described in the embodiment 1, is
enabled. Note that the XY operation circuit portion is connected to
the clock signal line. In practice, the XY operation circuit
portion operates the voltages applied from the X signal line and
the Y signal line, and outputs a signal of the result in accordance
with a clock signal voltage that is applied to the column of pixels
to be driven. This driving is performed twice within one frame
period to enable the image compression display of two gradations.
Of course, this number of gradations is variable.
[0091] As described above, the compressed image information of the
embodiment 1 (e.g., image information with 4.times.4 pixels
compressed at two gradations) is input into the image display unit
as shown in FIGS. 20 to 22, and displayed. Viz., the original image
information to be input is compressed by the graphic control chips,
with the number of gradations reduced, and passed to the image
display unit. And the image display unit can display the image
information with the number of gradations reduced in a unit of
pixel or in a unit of block by controlling the voltages applied to
the X wiring and the Y wiring and the clock signal employing the
signal control circuit within the image display unit. This means
that the system of the invention has the selectivity of the image
display unit.
[0092] With the above constitution, the high definition image can
be displayed, by making use of the visual characteristics of the
human being, and reducing the information with low degree of
recognition.
[0093] By taking this constitution, the image transmission method
adaptive to the high definition image display and the high speed
image display which are consistently effected can be provided.
* * * * *