JPH0422991A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To project an image having a large-capacity picture element without making the scale of a circuit large by supplying an identical image signal to a display electrode from a thin film transistor (TFT) selected and driven by the line wiring of every two adjacent lines in an identical horizontal scanning period. CONSTITUTION:The drain electrodes of two or more TFTs are connected to one of the display electrodes and the gate electrodes of the respective TFTs are respectively connected to two adjacent line wirings, then a source electrode is provided with a 1st substrate connected to a common column wiring and a 2nd substrate where a counterelectrode is formed. In the identical horizontal scanning period, the identical image signal is supplied to the display electrode from the TFT selected and driven by the line wiring of every two adjacent lines so as to drive liquid crystal display to display the image. Therefore, it is unnecessary to make the frequency of the image signal high because the line wiring is increased, and it will suffice, to make the frequency of the image signal high by as much as the increase of the row wiring. Thus, the image of the large-capacity is projected without making the circuit complicated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a liquid crystal display device that drives liquid crystal using an active matrix substrate on which thin film transistors (hereinafter referred to as TPT) are formed. The present invention relates to a low-cost liquid crystal display device that can display good images without fading.

BACKGROUND ART Liquid crystal display devices are considered promising among thin displays because they have characteristics such as low electrode consumption and easy full-color display, and in recent years, the display capacity has been increasing.

Conventionally, in a liquid crystal display device, a TPT, which is a nonlinear element, is formed by arranging row wiring and column wiring, and connecting the gate electrode to the row wiring and the source electrode to the column wiring, respectively, at each position where these intersect. A liquid crystal is sandwiched between a glass substrate in which a transparent display electrode for applying a voltage is connected to the drain electrode of the TPT, and a counter substrate on which a transparent electrode is formed, and for color display. Red, green, and blue color filters are also formed on the counter substrate.

Image display is performed by selectively driving the TPTs of necessary pixels using row wiring and column wiring, supplying an image signal to the transparent display electrode, and applying voltage to the liquid crystal together with the transparent counter electrode.

Conventionally, liquid crystal display devices using active matrix substrates with TPTs are prone to display defects due to defects in the TPTs, and in order to reduce these defects, a redundant structure in which two TPTs are provided for one display electrode has been proposed. (For example, Japanese Patent Laid-Open No. 121034/1983).

FIG. 7 shows an equivalent circuit diagram of a liquid crystal panel portion of a liquid crystal display device using a TPT active matrix substrate having a conventional redundant structure. Row device 1 which is a scanning line (Xo, Xz
Xz, '-', X i '', X240) signal line and null array 'IA2 (Y+, Yz, ...,
Display electrode 5 is placed in the area surrounded by Y i..., ¥37°).
(P++, ..., Pij, ...+,
Pz4o3to) 88,800 TFTs are arranged, and the drain electrode is commonly connected to each display electrode.
4 (T o lIl, T o211...TIIA
, Tl1ll+..., TijA, Tijs,...
...T 2403? OAI T z<ozto* ) is provided, and two TPTs each (TijA, TijB
) are arranged in adjacent rows m(X
i-1, Xj), and the source electrode is connected to a common column wiring (Yj).

A liquid crystal display device is constructed by sandwiching a liquid crystal between this active matrix substrate and a counter substrate on which transparent electrodes are formed, and for color display, red, green, and blue color filters are also formed on the counter substrate. .

The image is displayed as follows. Row wiring 2 has the 8th
A selective voltage (scanning signal) as shown in the figure is applied. During the horizontal scanning period (IH:NTSC
When the voltage shown in the figure is applied, Tn-1jA and Tn-Ijm become O.
becomes the N state, and the display electrode P n −1j
, Pnj are supplied with an image signal from the column wiring, and a voltage is applied to the liquid crystal together with the transparent counter electrode to display an image.

Further, after the next IH, Tnja and Tnj are turned on by a scanning signal applied to the row wiring Xn, and image signals are applied to Pn and Pnj via them. Therefore,
Since signal voltages are supplied to the Pn display electrodes by Tnb* and TrB A, even if one of these TPTs malfunctions, it will not result in a serious point defect.

Furthermore, in the display drive method of conventional liquid crystal display devices, display is not performed using the interlaced scanning method, but one image is projected for each field, and the frequency is set to 607 to make flicker less noticeable. .

Problems to be Solved by the Invention However, the following problems occur in a liquid crystal display device that displays an image using the above-described configuration and display driving method. When the display capacity of a liquid crystal display device increases, that is, when the number of row wiring and column wiring increases and the number of display electrodes increases, it becomes necessary to display even and odd field images at the same time. Since the frequency of image projection is twice that of the conventional example described above (30 Hz), a problem arises in that flicker is noticeable.

On the other hand, as a method for reducing the above-mentioned flicker, there is a method of sequentially scanning by interpolating image signals between scanning lines using clear vision technology. However, with this method, a problem arises in that the circuit for processing the image signal becomes complicated, its scale increases, and the cost increases. Moreover, not only the number of row wirings increases, but also the number of column wirings increases, resulting in an extremely high frequency image signal (for example, 480 row wirings,
In the case of 720 column wirings, the power consumption is 14.3 M) (z), so the power consumption of the IC increases and the IC easily generates heat, and the problem arises that the IC malfunctions and becomes impossible to display. .

Means for Solving the Problems In order to solve the above problems, the present invention supplies the same image signal to display electrodes from TPTs selectively driven by every two or more adjacent row wirings within the same horizontal scanning period. to drive the LCD and display images.

action The effects of the above technical means of the present invention will be explained below.

By supplying image signals to display electrodes from TPTs driven by adjacent row wirings within the same horizontal scanning period,
There is no need to increase the frequency of the image signal due to the increase in the number of row wirings. Therefore, it is only necessary to increase the frequency of the image signal by the increase in the number of column wirings, which means that the load on the IC can be reduced and images can be displayed without complicating the circuit.

Example Hereinafter, one embodiment of the present invention will be described in detail.

The active matrix substrate of the liquid crystal panel of this example is:
481 row wirings (Xo.

...X i + ..., X48°) and 720 column wirings (Yl, ..., Yj, ..., Y7□.)
, and a display electrode (P,) is formed in the area surrounded by them.

..., Pij, ...+ P41107□. )
345,600 TPT (Toll,
TIIA, T1111. ..., TIJa, Tzs
,・”+T480?!OA+Tnj10720
g), and each two T F T (TijA,
The gate electrodes of the Tijs) are connected to adjacent rows (Xil, Xi) across the pixel electrodes (Pij) to which the drain electrodes are commonly connected, and the source electrodes are connected to the common column wirings (Yj). It has a configuration connected to. FIG. 1 shows a signal waveform for displaying an image on the liquid crystal panel of this embodiment. As shown in the figure, by supplying the same scanning signal to every two row wirings, the TPTs driven by the row wirings are
The same image signal can be supplied from the same column wiring to the display electrodes connected to the same horizontal scanning period (IH). For example, in this embodiment, when scanning signals as shown in the figure are supplied to the row wirings Xn-1 and Xn, T n ija,' T
niji, Tnj. , Tnjl, are in the ON state, and the display electrodes Pnij, Pnj are connected via these.
, Pn+ij are supplied with an image signal from the column wiring, and a voltage is applied to the liquid crystal together with the transparent counter electrode to display an image. Furthermore, after the next IH, the scanning signal supplied to the row wirings Xn-'-, 1 and Xn+2
a, T n +1j+, T n +2j, Tn
+2j++ becomes ON state, and through it PN+1
An image signal is given to j, PN±2L P N +3j, and an image is displayed. In this example, the number of picture elements is 4.
Even with 80x720, images can be projected without increasing the scale of the circuit as in clear vision technology, and since the frequency of displaying each image is 60Hz, flicker is not noticeable. Furthermore, the frequency of the image signal is set to 7MH.
Since it can be made to about 14.3M7/ (720 lines/360 lines), it has the effect of suppressing IC power consumption and heat generation, and also suppressing malfunctions. Since it is displayed in plain image, it also has the effect of making point defects less noticeable.

FIG. 2 shows signal waveforms supplied to the liquid crystal panel in a second embodiment of the invention. The structure of the liquid crystal panel of this embodiment is the same as that of the first embodiment. As shown in FIG. 2, the same scanning signal is supplied to the two row wires Xn-1 and Xn in the even field, and the same scanning signal is supplied to the row wires Xn and Xn+ in the odd field.
By sequentially supplying the same scanning signal to the row wirings Xn1 and Xn, and the TPTs driven by the row wirings Xn and Image signals can be supplied.

This embodiment also has the same effect as the first embodiment, and furthermore, this embodiment also has the effect of being able to project the image signal at an accurate position in the vertical direction in each field of the interlaced scanning method.

FIG. 3 shows an equivalent circuit diagram of an active matrix substrate of a liquid crystal panel in another embodiment of the invention.

480 row wiring lines 21 (X,...
・Xi, ..., X4. . ) and 720 column wires 2
2 (Yl, ..., Yj, ..., Y, 2°), and a display electrode 25 (Pz,
...Pij, ..., P48゜7□. ) 345
Two TFT24 (Tza, T+
+s,..., TijA, Tija.

..., T4. . 7□. , T48°, 2°,) are formed, and two T F T (T ijl, T ij
11. ) have a configuration in which the gate electrodes are connected to a common row wiring Xi, and the source electrodes are connected to a common column wiring (Y j ).

By supplying the signals shown in FIG. 1 to the liquid crystal panel having the above-described configuration, when the scanning signals shown in the figure are supplied to the row wirings Xn-1 and Xn, T n -1jA,
Tn-1js, Tnja, Tnj are in the ON state, and the display electrodes PN-1j, P are connected via these.
An image signal is supplied to nj from the column wiring, and a voltage is applied to the liquid crystal together with the transparent counter electrode to display an image.

Furthermore, after the next IH, T n +1jA, T n
tljm, T n +2jl, T n +2jg,
becomes ON state, and through it Pn+1j, Pn+2
An image signal is given to j, and an image is displayed.

This embodiment has the same effect as the embodiment of the first invention, and even if a defect occurs in either TijA or TijB of the TPT, the pictorial display electrode to which the drain electrode is connected will always have a normal one. Since the image signal is supplied, point defect defects also have the effect of being hardly noticeable.

Furthermore, by supplying the signal waveform shown in Figure 2 to the above-mentioned liquid crystal panel, in addition to the above-mentioned effect, it is possible to project the image signal at an accurate position in the vertical direction in each field of the interlaced scanning method. have

FIG. 4 shows an equivalent circuit diagram of an active matrix substrate of a liquid crystal panel in another embodiment of the invention.

480 row wiring lines 31 (X,...X
B+ H+ HI Xaso) and 720 column wirings 32 (Yh..., Yj, .
, ...P 11+ ..., P48゜, 2゜)
345,600 T F Ta2 (T I
IA+T+lB+..., TijA, Tijm
..., T480?2゜A+T4B. , 2°, ) are formed, and each two T F T (TijA,
The gate electrode of TijB) is connected to a common row wiring Xi, the source electrode is connected to a common column wiring (Yj), and the electrode connected to the picture element electrode Pnj and the row wiring Xn-1 and TP
It has a configuration in which a storage capacitor 36 is formed with a gate insulating film of T.

FIG. 5 shows a signal waveform for displaying an image on the above-mentioned liquid crystal panel. As shown in the figure, in each field, a scanning signal with a selective voltage is sequentially supplied to each row wiring during a half period (1/2H) of the conventional horizontal scanning period, and to column wiring within a horizontal scanning period (IH). By supplying the same image signal to the display electrodes connected to the TPTs driven every two row wirings, the same image signal can be supplied to the display electrodes to which the TPTs driven every two row wirings are connected.

In this example, even if the number of picture elements is 480 x 720, the frequency of the image signal is set to about 7 MHz (14.3 MHz/(72
0/2), it is possible to suppress electrode consumption and heat generation of the IC, and has the effect of suppressing malfunction.

Furthermore, in the present invention, since the storage capacitor is formed in parallel with the capacitance of the liquid crystal, the image signal can be sufficiently retained and the reliability can also be improved.

In addition, as shown in FIG. 6 in the above liquid crystal panel, scanning signals are sequentially supplied to the two row wirings Xn-1 and Xn in the same horizontal scanning period in the even field, and in the odd field, the row wirings Xn and Xn± In addition to the above-mentioned effects, by sequentially supplying the scanning signals to the image sensor 1 during the same horizontal scanning period, there is also the effect that the image signal can be displayed at an accurate position in the vertical direction in each field of the interlaced scanning method.

In the above embodiments, a liquid crystal panel with a redundant configuration in which the drain electrodes of two TPTs are connected to one display electrode has been described, but a liquid crystal panel structure with a single TPT without a redundant configuration has the same effect. has.

Effects of the Invention As described above, according to the present invention, even though it has a large capacity picture element, the row layout tl1g! By supplying the same image signal to the display electrodes from TPTs that are selectively driven by every two adjacent row wirings within the same horizontal scanning period, such as supplying the same scanning signal for every two lines, clear vision technology can be improved. (images can be projected without increasing the scale of the circuit, and the flicker is not noticeable because the frequency of displaying one image is 60 seconds.Furthermore, since the frequency of the image signal can be reduced, the IC It also has the effect of suppressing power consumption and heat generation, and suppressing malfunctions.Furthermore, since one image is displayed using two picture elements, it also has the effect of making point defects less noticeable.

[Brief explanation of drawings]

1 and 2 are signal waveform diagrams supplied to the liquid crystal panel in an embodiment of the present invention, FIGS. 3 and 4 are signal waveform diagrams supplied to the liquid crystal panel in the embodiment of the present invention, and FIG. 5 ,
FIG. 6 is a diagram of signal waveforms supplied to the liquid crystal panel according to the embodiment of the present invention, FIG. 7 is an equivalent circuit diagram of a conventional liquid crystal panel section, and FIG. 8 is a diagram of signal waveforms supplied to the conventional liquid crystal panel. 1, 2L 31... Row wiring, 2.22.32.
...Column wiring, 4, 24.34...TFT
, 5.25.35... Transparent display electric bridge, 36...
...Storage capacity. Name of agent Patent attorney Shigetaka Awano Haka 1 person Figure Figure Off ii Own line interest West line TFT display type, ηi 1 in own size Column I#? - Line FT ゑ Arrival, & Accumulation gi Figure Figure Figure Sai 16 Self Line Da II Otsu FT Table 斤, Positive j k

Claims (6)

[Claims] (1) A plurality of column wirings and a plurality of row wirings, a display electrode arranged in an area surrounded by these wirings, and a valley electrode of two or more thin film transistors connected to one of each of the display electrodes. The gate electrode of each of the thin film transistors is connected to each of the two adjacent row wirings, and the source electrode of each of the thin film transistors is connected to a first substrate connected to the common column wiring, and a counter electrode. A second substrate on which is formed is placed opposite to each other so that the main surfaces of the display electrode and the counter electrode become opposing inner surfaces, and the display electrode on the first substrate and the counter electrode on the second substrate are formed. In a display device of a liquid crystal panel assembled with main surfaces facing each other so as to serve as opposing inner surfaces and a liquid crystal sandwiched in the facing space, one horizontal scanning period is selected for every two of the N and N+1 row wirings. The same scanning signal is supplied to each of the N+2 and N+3 row wirings after the horizontal scanning period has elapsed.
It is characterized by having a drive circuit that sequentially and periodically supplies the same scanning signal selectively during the horizontal scanning period, and sequentially supplies the same image signal to each of the column wirings within the horizontal scanning period to project an image. LCD display device. (2) In an even field of an image signal of the interlaced scanning method, selectively supplying the same scanning signal for one horizontal scanning period to every two Nth and N+1 row wirings, and
The same scanning signal selectively is sequentially and periodically supplied for one horizontal scanning period after the lapse of the horizontal scanning period for each of the 2nd and N+3rd horizontal scanning periods, and in the odd field, from after the horizontal scanning period in which the Nth scanning signal is supplied. N+1 and N of the row wiring
The same scanning signal is selectively supplied for one horizontal scanning period to every two +2nd row wirings, and the N+3rd and N+4th two row wirings
The same selective scanning signal is sequentially and periodically supplied for one horizontal scanning period after the horizontal scanning period has elapsed for each column, and the same image signal is sequentially supplied within the horizontal scanning period for each column wiring to display an image. 2. The liquid crystal display device according to claim 1, further comprising a drive circuit for outputting the liquid crystal. (3) A plurality of column wirings and a plurality of row wirings, a display electrode arranged in an area surrounded by these wirings, and a drain electrode of one or more thin film transistors in each of the display electrodes. are connected to each other, and the gate electrodes of the respective thin film transistors are connected to the common row wiring,
The source electrode of each of the thin film transistors has a first substrate connected to the common column wiring, a second substrate on which a counter electrode is formed, and the main surfaces of the display electrode and the counter electrode are opposing inner surfaces. In a display device having a liquid crystal panel assembled by facing each other and sandwiching a liquid crystal in the facing space,
A selective same scanning signal is supplied for one horizontal scanning period to each of the N-th and N+1-th row wirings.
A selective same scanning signal is sequentially and periodically supplied to each of the 2nd and N+3rd wires for one horizontal scanning period after the horizontal scanning period has elapsed, and the same image signal is sequentially supplied to each of the column wirings within the horizontal scanning period. 1. A liquid crystal display device comprising a drive circuit for supplying power and displaying an image. (4) In an even field of an image signal of the interlaced scanning method, selectively supplying the same scanning signal for one horizontal scanning period to every two row wirings N and N+1, and
The same scanning signal selectively is sequentially and periodically supplied for one horizontal scanning period after the lapse of the horizontal scanning period for each of the 2nd and N+3rd horizontal scanning periods, and in the odd field, from after the horizontal scanning period in which the Nth scanning signal is supplied. N+1 and N of the row wiring
The same scanning signal is selectively supplied for one horizontal scanning period to every two +2nd row wirings, and the N+3rd and N+4th two row wirings
The same selective scanning signal is sequentially and periodically supplied for one horizontal scanning period after the horizontal scanning period has elapsed for each column, and the same image signal is sequentially supplied within the horizontal scanning period for each column wiring to display an image. 4. The liquid crystal display device according to claim 3, further comprising a drive circuit for outputting the liquid crystal. (5) A plurality of column wirings and a plurality of row wirings, a display electrode arranged in an area surrounded by these wirings, and a drain electrode of one or more thin film transistors in each of the display electrodes. are connected to each other, and the gate electrodes of the respective thin film transistors are connected to the common row wiring,
The source electrode of each of the thin film transistors is connected to the common column wiring, and is connected to the electrode connected to the N-th display electrode.
The first row has a capacitor formed using the first row wiring as an electrode.
and a second substrate on which a counter electrode is formed are arranged to face each other so that the main surfaces of the display electrode and the counter electrode become opposing inner surfaces, and a liquid crystal is sandwiched in the opposing space, whereby a liquid crystal panel is assembled. In the display device, a selective scanning signal is supplied for one horizontal scanning period to the Nth row wiring, and the N+ of the row wiring is supplied with a selective scanning signal for one horizontal scanning period.
First, after the horizontal scanning period has elapsed, a selective same scanning signal is sequentially and periodically supplied for one horizontal scanning period, and scanning signals are supplied to each of the column wirings to the Nth and N+1th row wirings, for two horizontal scanning periods. 1. A liquid crystal display device comprising a drive circuit that displays an image by sequentially supplying the same image signal to each display. (6) In the even field of the image signal of the interlaced scanning method, the same image signal is sequentially supplied to each row wiring every two horizontal scanning periods in which the scanning signal is supplied to the N and N+1th row wiring, and in the odd field, The above N for each column wiring
6. The liquid crystal display device according to claim 5, further comprising a drive circuit that projects an image by sequentially supplying the same image signal every two horizontal scanning periods in which the +1st and N+2nd scanning signals are supplied.