JPS6382177A - Display device - Google Patents

Abstract

PURPOSE:To prove the reliability of the titled device by using a complementary element so as to form a selecting element thereby decreasing the level of a drive signal for signal selection. CONSTITUTION:A MOS selection element Mij consists of N-channel elements MMij and P-channel elements PMij being complementary elements, and the gates are connected respectively to signal lines Ai and the inverse of Ai. Then a data signal line Dj and one end of a liquid crystal display element Cij are connected between the source and drain of the elements NMij and PNij. Moreover, the other end of the liquid crystal element Cij is connected to a common target terminal T. In giving a signal A to the data signal line Dj, a drive signal of opposite polarity is given to the address signal line Ai, inverse of Ai thereby conducting the elements NMij, PMij at each pulse period. Thus, the input signal is given to the liquid crystal element Cij through the elements NMij and PMij, the element PMij is conducted sufficiently when the input signal is at a high level and the N-channel element NMij is conducted sufficiently when the signal is at a low level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display device using, for example, a liquid crystal display element.

[Summary of the invention]

The present invention relates to a display device, and by forming a selection element using complementary elements, the level of a drive signal for signal selection is reduced and the reliability of the device is improved.

[Conventional technology]

For example, various active matrix display devices using liquid crystal display elements have been proposed.

That is, FIG. 5 shows the configuration of the main part of an example, and includes, for example, data signal lines Dj for the number of horizontal pixels to which image data signals are sequentially supplied every pixel period, and drive pulse signals sequentially supplied every horizontal period. An MO8 selection element Mi is provided with address signal lines Ai as many as the number of scan lines to be supplied, and is provided perpendicularly to each other, and a dart is connected to the address signal line Af at each intersection point.
j is provided, and the data signal line DJ is connected to this MO8 element Mi.
It is connected to one end of the liquid crystal display element C1j via the source and drain of C1j. Note that the other end of the liquid crystal element C1j is connected to a common target terminal T.

Therefore, in this device, any address signal line Aj
When the K drive (pulse) signal is supplied, the selection element Mij whose date is connected to this signal line becomes conductive, and the image data sequentially supplied to the data signal line Dj K is sequentially supplied to the liquid crystal element Cij. As a result, so-called surface-scanned image data is transferred to the liquid crystal elements C arranged in an IJ rack pattern.
Displayed at ij.

By the way, in this device, when driving a liquid crystal display element, for example, so-called AC driving is performed for the purpose of preventing deterioration of the liquid crystal. That is, as shown in FIG. 6, for example, the data signal supplied to the data signal line Dj for each field is inverted with respect to the potential VT of the target terminal T.

However, in that case, the drive signal supplied to the dart of the MO8 element Mij is lower than the lowest potential V of the data signal at the time of interruption.
It is lower than St, and requires a level higher than the highest potential VS2 of the data signal by more than the threshold voltage vth of the element when conductive. Therefore, the amplitude of this drive signal is l VS2 - VSI l + vth, and it is necessary to make the dirt breakdown voltage of the MO8 element Mij to which this signal is supplied extremely large. Moreover, the reliability of the device has been reduced thereby.

Furthermore, since a high-level drive signal is used, radiation tends to increase due to so-called clock noise.

Since the holding potential of the signal is likely to decrease due to feed-through noise when the MO8 element is cut off, there is a risk that the dynamic range will decrease and the contrast of the image will be insufficient due to this.

[Problem that the invention seeks to solve]

As described above, the conventional technology uses a large-level drive signal, which causes problems such as a decrease in reliability, an increase in radiation, and a tendency to decrease the dynamic range.

[Means for solving problems]

The present invention provides a plurality of first signal lines Dj extending in the vertical direction and arranged in parallel, and a plurality of second signal lines Ai extending in the horizontal direction and arranged in parallel. The first of these In a display device in which a pixel electrode Cij is provided at each intersection of the second signal line via a selection element Mij, each of the selection elements is a pair of complementary elements NMij.

This display device is characterized in that it is formed of PMij and is driven by drive signals (AijQ) of opposite polarity.

[Effect]

According to this method, complementary elements are used so that the high potential period and low potential period of an input signal are selected through different types of elements, thereby improving the drive signal supplied to these elements. The level can be reduced to an amount equal to the amplitude of the input signal.

〔Example〕

FIG. 1 shows a wiring diagram. In this figure, two address signal lines Ai (Ai, ' and 'i) are provided, and an MO8 selection element Mij is connected to an N-type element NMij and P
The darts of these elements NMij and PMij are connected to the signal line Ai, respectively.
and M. And these elements NMij and P
The data signal line Dj is connected between the source and drain of Mij.
and one end of the liquid crystal display element C1j are connected. Further, the other end of the liquid crystal element C1j is connected to a common target terminal T.

In this device, the data signal line Dj is connected to the data signal line A shown in FIG.
When a signal as shown in K is being supplied, driving signals of opposite polarity as shown in B and C in the same figure are supplied to the address signal line hi, and elements NMij and PMij are connected to each other. K so that it is conductive during the pulse period.

Therefore, in this device, the input signal passes through the elements NMij and PMij to the liquid crystal element C during the pulse period of each drive signal.
1j, and P during the high potential period of the input signal.
Since the type element PMij is sufficiently conductive and the N type element NMij is sufficiently conductive during the low potential period, the amplitude of each drive signal can be made equal to the amplitude lVS2 Vstl of the input signal.

Furthermore, in the above device, the high potential period (field) of the input signal is the P-type element PMij, and the low potential period is the N-type element N.
Since only Mij needs to be conductive, each address signal line A
The drive signals for i and stone may be alternately supplied for each field as shown in the waveform diagram H. Furthermore, in this case, the wave height level of each drive signal is K, as shown in the figure.
The pedestal level during the high potential period of the input signal is VS'2,
Bestial level during low potential period ”S'l, P us
The threshold voltage of the child PMij is Vthp, and the N-type element N
It is also possible to set the threshold voltage of Mij to VthN and set them as VS2-VthpVB2+vthN, respectively.

Display is performed in this way, and since the level of the drive signal can be reduced with the above-mentioned device,
There is no need to increase the dart withstand voltage of each selection element, and the reliability of the device is improved.

Furthermore, the occurrence of radiation due to clock noise is reduced, and in particular when the signals B and C in the waveform diagram are used, the drive signals cancel each other out, so radiation can be reduced to approximately zero.

Furthermore, FIG. 3 shows a specific example of the configuration of the circuit R-turn, and in the figure, a P-type element PMij and an N-type element NMij are respectively provided between the data signal line DJ and the transparent electrode constituting the liquid crystal display element C1j. and these elements P
At the center of Mij and NMij, address signal lines Ai and snoring extensions provided above and below the transparent electrodes are provided, respectively, to form darts.

Therefore, according to this configuration, drive signals of opposite polarity are passed between adjacent address signal lines, so that clock noise entering each transparent electrode is neutralized and a reduction in dynamic range is prevented.

Note that FIG. 4 shows another example of the configuration of the selection element, where A is a so-called double gate, which is particularly effective in reducing charge leakage between the data signal line Dj and the liquid crystal display element Cij. can. Further, B is a structure in which the midpoints of the double gates are connected to each other, which reduces leakage as described above, and improves strength particularly against the generation of static electricity due to rubbing treatment during the manufacturing process.

Note that this device is applicable to devices using all MO8 elements such as polysilicon, amorphous silicon, and crystal silicon.

〔Effect of the invention〕

According to the present invention, by using complementary elements, the high potential period and the low potential period of the input signal are selected through different types of elements, so that the drive signal supplied to these elements is It is now possible to reduce the level of the input signal to a magnitude equal to the amplitude of the input signal.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram of an example of the present invention, FIGS. 2 to 4 are diagrams for explaining the same, and FIGS. 5 and 6 are diagrams for explaining a conventional device. DJ is a data signal line, Ai is an address signal line, NMij
is an N-type element, PMij is a P-type element, Cij is a liquid crystal display element, and T is a target terminal.

Claims (1)

[Claims] A plurality of first signal lines extending in the vertical direction and arranged in parallel and a plurality of second signal lines extending in the horizontal direction and arranged in parallel are provided. In a display device in which a pixel electrode is provided at each intersection of these first and second signal lines via a selection element, each of the selection elements is formed of a pair of complementary elements, and A display device characterized in that these are each driven by drive signals of opposite polarity.