JPH01310326A - Active matrix type display panel device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention uses a display medium such as a liquid crystal, and uses an active matrix type display medium in which diodes are distributed and incorporated within the display surface as drive elements for display driving each pixel. The display panel device includes pixel electrodes arranged in rows and columns within a display surface on one side of a pair of substrates of the display panel, diodes in both positive and negative directions for display driving each pixel, and pixel electrodes arranged in one row. The present invention relates to a device including a scanning electrode provided in common to the other substrate, and a data electrode facing pixel electrodes arranged in a column direction on the other substrate side.

[Conventional technology]

The active matrix type display panel device using the above-mentioned liquid crystal or the like as a display medium is suitable for displaying a 3D image such as on a television, in which at least 10,000 pixels are arranged in rows and columns or in a matrix on the display surface. In order to reduce so-called crosstalk between pixels and make the display clearer, nonlinear elements, usually III elements, are incorporated as drive elements distributed within the display surface. A thin film transistor as a three-terminal element or a III-diode as a two-terminal element is used as this driving element, but the latter has the advantage of being easy to incorporate into a display panel and reliable operation.The present invention uses this diode. This invention relates to an active matrix type display panel device used as a driving element, and a typical example of a conventional display panel of this type will be described below with reference to FIG. 7 and subsequent figures.

FIG. 7 shows an equivalent circuit for 4N elements, where the solid line indicates the part to be incorporated into one of the pair of substrates of the display panel, and the broken line indicates the part to be incorporated into the other substrate, which is the display medium between the two substrates. are indicated by hatch lags. One of the substrates is a so-called active matrix substrate, and has a large number of pixel electrodes 10 arranged in rows and columns on its surface, and a scanning electrode 30 provided in common to the pixel electrodes 10 arranged in rows in this figure. and a driving element 20 including positive and negative diodes 20P and 20n provided for each pixel electrode and connected in antiparallel between the pixel electrode 10 and the scanning electrode 30. Data electrodes 40 are provided on the other substrate so as to face the pixel electrodes arranged in the column direction.
The rod 40 and each pixel electrode IO form a pixel, which is a display unit, with a display medium such as a liquid crystal placed therebetween.

FIG. 8 is a plan view showing the structure of 1 m element of the above-mentioned active matrix substrate. The 0 pixel 1 pole 10 has an almost rectangular outline, and the scanning electrode 30 has an elongated shape in the row direction and is transparent. Formed from a conductive film. diode 20
P and 20n are each formed into a rectangular shape as shown in the figure, for example, from amorphous silicon or the like grown in a 3N configuration of p, l, and n. The positive direction diode 20P is the scanning voltage 8
Built on i30 and made of aluminum etc. &1E1117
The negative direction diode 20n is conversely formed on the pixel electrode lO and connected to the pixel electrode 10 through the pixel electrode lO.
Scanning voltage by 7! Connected to f130. A thin insulating film 6 is provided below the connection film 7 so as to commonly cover both diodes in order to insulate the side surfaces of the diodes from it.

The reason why diodes in both positive and negative directions are provided as driving elements is to perform so-called AC driving in which the polarity of the scanning voltage applied to the scanning electrode 30 is switched between positive and negative for each scan period of the display panel. When the voltage is positive, the diode 20p in the positive direction is conductive, and when the scanning voltage is negative, the diode 2On in the negative direction is conductive.

FIG. 9 shows the procedure for driving the display panel configured as described above, in which the left half of the figure corresponds to a scan period in which the scan voltage is positive, and the right half corresponds to a scan period in which the scan voltage is negative. The scanning voltage S1 in the figure (bl) is applied to the first scanning electrode 30 from the top in FIG. Its polarity is switched between positive and negative at each scanning period as shown in the figure.The scanning voltage S2 in the same figure (C) is applied to the second scan 1t8i30 from the top in Fig. 7, and has the same waveform as in the case of 1t8i30 in the same figure. However, its timing is delayed by a unit time of 6t. In other words, the scan period for the second scan electrode is shifted by a unit time of 111 from that for the first scan electrode.In a display panel that uses diodes as drive elements, the scan period is similarly shifted for each scan electrode by a unit time of 111. The time is sequentially shifted by 4t.

FIG. 7A shows an example of display data given to one of the data electrodes 40 in FIG.
This data voltage Dl (1·l to n) is switched and applied every time. However, it is assumed that pixels are arranged in n rows on the display panel. These data D1 originally specify the display brightness of each pixel with its value, but for the sake of simplicity, the figure shows a case where the display brightness is specified with simple plus/minus or ~. There is. Now, when the first data voltage 01 is applied to the data voltage B110 in the first unit time At, the scan voltage S1 applied to the first scan electrode includes the selection voltage Vs within that unit time.
A display corresponding to the data voltage DI is performed on the corresponding first pixel, and this display state is maintained throughout the scanning period by a holding voltage vh following the selection voltage Va. Similarly, when the first data voltage DI is applied,
By the selection voltage Vs of the scan voltage 51 applied to the first scan electrode, a corresponding display is made in the first pixel and is maintained for one scan period.

During the above display operation, each pixel type 8i10 and data electrode 40
The display voltage applied to the display medium between is the difference or sum of the scan voltage S1 and the data voltage DI, and this waveform is shown for the first pixel in FIG. 9(d). In a scanning period in which the scanning voltage is positive, for example, - of the data voltage D1 specifies brightness, and t specifies darkness. However, as can be easily seen, in a scan period in which the scan voltage is negative, this relationship between brightness and darkness is reversed, so that the data voltage (old) is compensated for, or given in a relationship in which the polarity is opposite to that for a positive scan period.

The principle of display driving described above is based on, for example, Japanese Patent Application Laid-open No. 5
This is explained in Japanese Patent No. 9-57273, so please refer to this for details.

[Problem to be solved by the invention]

However, in the above-mentioned conventional active matrix display panel device, the display area of each pixel is not necessarily a correct square, resulting in a problem that the image quality deteriorates. As can be seen from Figure 8, the pixel tmto has a cutout in its lower right corner, but in addition to this, the diode 20n and connection wA7 are light-shielding, so the area of the cutout is quite large on the display. growing. Furthermore, in order to improve the display clarity of this type of display panel, it may be necessary to increase the number of diodes connected in series, and for this purpose the location where diodes 20p and 20n are installed is expanded upward in the diagram. As a result, the shape of the actual display area of each pixel becomes considerably distorted.

Another problem is that it is difficult to test the positive and negative diodes separately. This test is performed by applying a test voltage between the pixel i+ and the scanning electrode by applying a probe to the edge of the pixel, but if a short-circuit defect occurs in one of the diodes, what happens as shown in Figure 7? You can't tell if a diode is defective unless you separate one of them.Also, by cutting off the polarity of the test voltage, you can test the forward characteristics of each diode separately, but you cannot test the reverse characteristics at all. As can be easily seen, this problem is due to the fact that both diodes are fixedly connected in antiparallel between the pixel electrode and the scan electrode.

Based on such circumstances, an object of the present invention is to reduce the display irregularities of each pixel electrode.

A second but important object of the present invention is to enable positive and negative diodes to be tested separately from each other.

[Means to solve the problem]

According to the present invention, the above object is achieved by providing pixel electrodes arranged in rows and columns within a display surface on one side of a pair of substrates of a display panel as described at the beginning, and diodes in both positive and negative directions that drive each pixel for display. Scanning is applied to an active matrix display panel device including a scanning electrode provided in common for pixel electrodes arranged in one row, and a data electrode facing the pixel electrodes arranged in a column on the other substrate side. Between the electrode and the pixel electrodes arranged on one side of the electrode, only diodes in one direction associated with those pixel electrodes are connected, and between the scanning electrode and the pixel electrodes arranged on the other side, the diodes of those pixels are connected. This is achieved by connecting only the diodes in the other direction associated with the electrodes.

In the above configuration 1. It is desirable that the positive and negative diodes associated with a certain pixel M1 be placed as far apart from each other as possible, and it is particularly advantageous to place both diodes on the diagonal of the rectangle of the pixel electrode.

[Effect]

As described in the above configuration, the present invention connects only diodes in one direction associated with the pixel electrodes between the scanning electrode and the pixel electrodes arranged on one side thereof, and By connecting only the diodes in the other direction associated with those pixel electrodes between the pixel electrodes arranged in one direction, the positive direction diode and negative direction diode associated with a certain pixel electrode can be connected to the pixel electrode. 1 on both sides
This divides the area occupied by the diode into a pair of scanning electrodes, thereby reducing irregularities in the display shape of each pixel, and applying a test voltage between the pixel electrode and each of the scanning double positive electrodes on both sides. This problem is solved by allowing positive and negative diodes to be tested separately from each other.

Although the conventional display driving method has the problem of not being able to drive a display panel with the above configuration, as in the example described later, it is possible to drive the display panel with one polarity from the scanning electrode through a diode in one direction. This problem can be solved without any confusion by using a display drive method in which the pixel electrodes arranged on one side are driven for display, and the pixel electrodes arranged on the other side are driven for display by a scanning voltage of the other polarity via a diode in the other direction. can be solved.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is an equivalent circuit diagram showing the basic configuration of an active matrix type display panel device according to the present invention, which will be explained first.

This FIG. 1 is designated by the same 91 il as the previous FIG. 7, and the same reference numerals are used. Pixel type 11+i is on the active matrix substrate side shown by the solid line.

The point that the driving element 20 and the scanning electrode 30 are provided is the same as before, but all the positive direction diodes 20p forming the driving element 20 are connected between the pixel electrode lO and the scanning type fI 20 above it in the figure. and negative direction diode 2
0n all pixels t8ilO and its lower scan 1 to pole 2
0. Therefore, a certain scan 1t8i12
0 as the center, only a positive direction diode 20P is provided between it and the pixel electrode 10 arranged above it, and a negative direction diode 20n is provided between it and the pixel electrode 10 arranged below it. The mind is set.

A pixel electrode in which data electrodes 40 indicated by broken lines are arranged in a column direction on the other side of the display panel Fi! A display medium 50 that is provided opposite to each pixel electrode 10 and indicated by a hatched lag
The point that pixels are formed on both sides is the same as in the conventional case.

In addition, in the display panel according to the present invention, in order to drive the display of pixels arranged in n rows, as shown in the figure, n+1 pixels are arranged in n rows.
scanning electrodes are provided. For convenience of explanation below, these scanning electrodes! The scanning voltage given to 0 is 51(1・1
~n+1), and the data voltage applied to one of the data electrodes 40 is represented by DI(1-1-n), respectively.

FIG. 2, corresponding to the previous FIG. 8, illustrates the structure of the active matrix substrate of the display panel according to the present invention, focusing on IWi elements. The positive and negative diodes 20P and 20n are diagonally arranged with respect to each rectangular pixel electrode 10.
In addition, in this example, all the pixel electrodes are arranged on diagonal lines in the same direction. Of course, the direction of this diagonal line may be such that the pixels arranged in the row or column direction are alternated with respect to the column.
Since a cross section is shown in the direction of arrows, the manufacturing process and structure of this active matrix substrate will be briefly explained below with reference to this cross section.

Insulation for boards! The plate 1 is usually a transparent glass plate, and a very thin transparent conductive film 2 made of tin oxide or the like is deposited on it, and the pixel [110 and the scanning type 8i30 are formed by photo-etching it. . The main body of the diode is 1
A semiconductor film 4 made of amorphous silicon or the like is sandwiched between a pair of thin light-shielding films 3 and 5 made of Cr, etc., and is patterned into a rectangular shape as shown in FIG. An insulating film 6 is deposited or grown and photo-etched into a pattern that commonly covers the two diodes, and a connection window 6a is formed on the top surface of the main body of each diode.
An aluminum film or a conductive film is used for the connecting film 7, which is deposited so as to be in conductive contact with the diode main body through the window 6a, and then photoetched to form a second film.
A rectangular connecting film 7 as shown in the figure is formed to connect the diode to the scanning electrode or the pixel electrode.

Now that the explanation of the configuration of the display panel according to the present invention has been completed, the display driving method or system thereof will now be explained with reference to FIG.

FIG. 4 illustrates the waveform of the scanning voltage Si suitable for display driving the display panel device according to the present invention in the same manner as the previous FIG.
An example of a data voltage Di applied to 40 is shown.

Of the two pulse trains shown surrounded by dots and lines in the diagram, each consisting of n data voltages o1, the left side corresponds to a positive scanning voltage, and the right side corresponds to a negative scanning voltage. A short period of time indicated by X in the figure is taken in between, and display data can be loaded into a circuit such as a shift register that outputs a data voltage to the data electrode 40, for example, within this period of time. Data voltage O1 within pulse train
It is assumed that the switching is performed every unit time Δt as in the conventional case.

In this embodiment, as shown in FIG. 1, a positive direction diode 20P is connected to the first scanning electrode 30 from the top, so if a positive voltage is applied to this as the first scanning voltage S1, 1 The pixels in the row can be driven for display. Figure 4 (bl
The waveform of this scanning voltage sl is shown in , and as shown in the figure, the selection voltage Vs is superimposed within the first unit time 4 on the holding voltage vh that is maintained for n unit times 11t. It is. This positive scanning voltage Sl causes the pixels in the first row to display a display corresponding to the data voltage DI, as in the conventional case, and this display state is maintained while the positive holding voltage continues.

It is natural to give this first scanning voltage Sl a negative voltage waveform as shown by the broken line in the figure, but as can be seen from Figure 1, since there are no pixels above the first scanning electrode, the negative voltage waveform The scanning voltage 51 cannot have any actual display driving effect.

The figure (C) shows the waveform of the scanning voltage S2 applied to the second scanning electrode.
The process starts at time t22, causes the pixels in the second row to display a display corresponding to the data voltage 02, and holds it for n unit times At, and then ends at time t22. The negative scanning period is at time t23
This timing corresponds to the data voltage Di as shown. Therefore, from time t22 to L23
The time until then is x-At. As a result, in this negative scanning period, the pixels in the first row display a display corresponding to the data voltage DI. The time from time L24 when the negative scanning cycle ends to time t21 when the positive scanning cycle starts again is x
+ht.

Similarly, during the positive scan period of the first scan voltage St applied to the first scan electrode, the i-th pixel displays a display corresponding to the data voltage DI, and during the negative scan period, the display corresponds to the data voltage DI. 1
The data voltage 111-1. is applied to the pixel in the row. The waveforms of the scanning voltages Sn and Sn+l are respectively shown in FIGS. However, as can be easily seen, the positive scanning voltage Sn has no practical meaning in driving the display, as shown by the broken line in the figure.

FIG. 5 is for reference to help understand the explanation of the above-mentioned display driving method. The waveforms of scanning voltages S2 to Sn+l are shown in (1) to (n) of the figure, respectively. For example, regarding the scanning voltage s4 in VA, the positive scanning period starts at time a in FIG.
A negative scanning period begins at , ends at time d, and returns to the aforementioned time a.

FIG. 6 is similar to FIG. 5, but shows a slightly different display driving method from the front of the display panel according to the present invention. In this embodiment, in order to simplify the waveform of each scanning voltage compared to the previous actual AI example, the way the data voltage DI is applied to the data electrodes shown in FIG. The n data voltages in Figure (a) are for the positive scanning period, and after they are completed, the negative voltage in Figure (C) is Given n data voltages 01 for a scanning period, the time y-x-1 after its end
After 1t has elapsed, it returns to the beginning of the same figure (al). Waveforms within the positive scanning period of the scanning voltage 5l-5n are shown in (b) to (e) of the same figure, and (1) to (e) of the same figure. Scanning voltage S2~Sn+l
The waveforms within the negative scan period of are shown, respectively.

All the scanning voltages in this embodiment have positive and negative scanning periods equal to the time nat+x as shown in the figure, and the rescanning periods are consecutive to each other.For example, this is true for the fourth scanning voltage S4. Looking at the same figure (a
), the positive scanning period begins at time a in FIG. However, at the same time as this, the data voltage D3 of 00 in the same figure
The negative scanning period begins at time C in FIG. This negative scanning period ends at time d, which corresponds to the end of data voltage D3 or the beginning of data voltage D4 in FIG. 2A, and immediately continues to time a.

As will be seen from now on, it is necessary to slightly adjust the timing of applying the data voltage S1 to the data electrodes between the positive scan period and the negative scan period in this embodiment.
-Sn+1 can all have very simple waveforms.

Note that in the embodiments described above, the scanning electrode is provided in common for the pixel electrodes arranged in the row direction, but the scanning electrode is provided in common for the pixel electrodes arranged in the column direction, and therefore the data electrode is provided in common for the pixel electrodes arranged in the column direction. It is clear that the present invention can be applied as is to a display panel that is commonly provided to pixel electrodes arranged in rows. In addition, the structure of the display panel and its display driving method shown in the embodiments are merely illustrative, and the present invention is not limited to such examples, and the present invention may be carried out in various modified forms a within the scope of the gist. can do.

〔Effect of the invention〕

As explained above, in the present invention, one of the display panels
On one side of the pair of substrates, pixel electrodes are arranged in rows and columns within the display surface, diodes in both positive and negative directions drive each pixel, and a scanning electrode is provided in common for the pixel electrodes arranged in two rows. For an active matrix display panel device, which has data electrodes facing pixel electrodes arranged in columns on the other substrate side, those pixel electrodes are arranged between the scanning electrode and the pixel electrodes arranged on one side thereof. Only the diodes in one direction associated with the scan electrode are connected, and only the diodes in the other direction associated with those pixel electrodes are connected between the scanning electrode and the other pixel electrodes arranged on the side. First, a positive direction diode and a negative direction diode provided along with each pixel are distributed and arranged on the scan t8i side on both sides of the pixel electrode, reducing irregularities in the display shape of each pixel and improving image quality. can be improved.

Second, when testing active matrix substrates, by applying a test voltage between the pixel electrode and the scanning electrodes on both sides of it, it is possible to separate the positive-direction diode and the negative-direction diode from each other. This is made possible by the present invention. This feature is of course useful for quality control of active matrix display panel devices, and it also allows defects to be removed based on accurate test results.
Various ideas have been made to make testing of drive elements easier, which is very effective in improving the yield of display panels and reducing manufacturing costs. However, as can be seen from the above-mentioned embodiments, the display panel of the present invention has problems such as a decrease in the utilization rate of the area of the display panel. This problem can be solved very easily without complication.

In this way, the present invention provides display i! of an active matrix type display panel device. It is expected that these 11 display panels will contribute to the further development and spread of these 11 display panels in the future, as they have the characteristics of improving quality, performance, and economical efficiency.

[Brief explanation of the drawing]

Figures 1 to 9rj! 1 is an equivalent circuit diagram showing the basic configuration of an active matrix type display panel device according to the present invention, and FIG. 2 is a scanning voltage diagram illustrating an active matrix display driving method illustrating its structure. FIG. 5 is a waveform diagram of the scanning voltage showing the waveform in a slightly different form, and FIG. 6 is a waveform diagram of the scanning voltage showing a different example of the display driving method. FIG. 7 and subsequent figures relate to the prior art; FIG. 7 is an equivalent circuit diagram of a typical example of a conventional active matrix type display panel device, FIG. 8 is a partially enlarged plan view of an active matrix substrate showing its structure,
9th rj! J is a scanning voltage waveform diagram showing the display driving method. In figure 0, l: wA edge substrate, li3 bright conductive film, 3. S: Shade 1 model, 4: Semiconductor film, 6: Insulating film, 6a: Window, 7: Connection film,
loi pixel electrode, 20: drive element, 20p: positive direction diode, 20n: negative direction diode, 30: scanning electrode,
40: data electrode, 50: display medium or liquid crystal, a-
d: Time, Ol (1-1=n): Display data voltage,
5l (1=l-n+1): Scanning voltage for display driving, t2
1 to t24: time, At: unit time, vh: holding voltage,
vs: selection voltage; x, y: time. Iri I joined patent attorney Yamaguchi, Mushi. Figure 1 Figure 21!1 Figure 5

Claims (1)

[Claims] Common to the pixel electrodes arranged in rows and columns within the display surface on one side of a pair of substrates of the display panel, the diodes in both positive and negative directions that drive each pixel for display, and the pixel electrodes arranged in the row (column) direction. In a display panel device comprising a scan electrode provided and a data electrode facing pixel electrodes arranged in a column (row) direction on the other substrate side, there is a space between the scan electrode and the pixel electrode arranged on one side thereof. connects only the diodes in one direction associated with those pixel electrodes, and connects only the diodes in the other direction associated with those pixel electrodes between the scanning electrode and the other pixel electrodes arranged on the side. An active matrix display panel device characterized by: