JPS6039620A - Image display device - Google Patents

Abstract

PURPOSE:To perform such AC drive that the potential between picture elements is held by equalizing the one-side electrode potential of plural display potential storage capacitors which are connected in common to the variation amount of the potential of an opposite substrate when the electrode potential of the opposite electrode is varied. CONSTITUTION:Signals which turn on transistors (TR) is gate electrode groups R1, R2, R3...RN are applied in periods W and W', and the TRs in R1, R2, R3...RN are turned off in common. Then, the electrode potential Vc of the opposite substrate and the one-side potential V1 of a display potential storage capacitor vary in periods E and E', and picture element data Mi1, Mi2, Mi3...MiN are inverted in W and W' symmetrically about the electrode potentials Va and Vb of the opposite substrate, and inverted even in E and E' similarly. Then, Vc and V1 is equalized in variation amount so as to obtain symmetrical AC waveforms as data waveforms Vi1, Vi2...ViN of picture-element electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image display device that drives liquid crystal using a plurality of transistor elements formed on the same substrate as switching elements.

The configuration of an image display device using a liquid crystal is similar to that on the same substrate.
The configuration of one pixel is as shown in Figure 1, consisting of a transistor array in which a group of gate electrodes and a group of source electrodes are arranged orthogonal to the transistor a), a display potential storage capacitor (2),
Liquid crystal display pixel drive electrode (8), liquid crystal for one pixel (liquid crystal display pixel) (4), gate electrode (0, and source electrode (6)
). The transistor turned on by the gate signal transmits the source signal to the liquid crystal display pixel drive electrode, accumulates charge in the display potential storage capacitor, controls the alignment of the liquid crystal molecules, and provides electro-optical modulation to display an image. The display potential storage capacitance needs to have a sufficiently large value in order to prevent the potential from decreasing due to discharge of charges due to the resistance of the liquid crystal and the transistor when the transistor is off.

An object of the present invention is to provide an image display device having novel features in its driving method while making use of the simple display structure as described above.

FIG. 2 shows an equivalent circuit of the pixel configuration shown in FIG. 16. The liquid crystal (4) for one pixel has a capacitance (represented by LO), and the liquid crystal display pixel drive electrode (3) has a capacitance C of the alignment layer on the electrode.
I+CI, the series capacitance of C1+"LQ+ON is C, the electrode potential of the pixel is VD, and the electrode potential of the opposing substrate is Vo. is the capacitance Os, and the potential of one side electrode is V.CGD is the gate-drain type capacitance of the transistor (1), and Os+C is selected to be sufficiently larger than OGD.Gate electrode (6) The potential of the source electrode is VG, and the potential of the source electrode is VA.

When the transistor is turned on by a gate signal, a source signal is transmitted into the pixel, and charges are accumulated in O, O as the electrode potential VD of the pixel as shown on the left in FIG. 3, and when the transistor is turned off, the electrode potential is held. In that state, V,,Vc
simultaneously or continuously, resulting in V1+V,
When the amount of change in electrode potential is equal to or close to Vc + V, the pixel electrode potential becomes VD + V as shown on the right in Figure 3, and the voltage at the liquid crystal display pixel drive electrode (8) becomes VD - va. and maintains the same voltage as before.

The image display device of the present invention uses a liquid crystal sandwiched between a substrate on which a plurality of transistor elements are formed and a counter substrate on which a conductive film is formed to perform display based on this base material, and realizes AC drive. When changing the electrode potential of the counter substrate, one side electrode potential of a plurality of commonly connected display potential storage capacitors of the liquid crystal display pixels is changed simultaneously or one after the other, so that the result is equal to the amount of change in the electrode potential of the counter substrate. With respect to the data series before the electrode potential of the opposing substrate changes, a data series that is inverted based on the electrode potential of the opposing substrate is added to the source bus and stored in the pixel. The summary shall be as follows.

FIG. 4 is a timing chart showing one embodiment of the present invention. The pixels of the configuration shown in FIG. 1 are arranged in a matrix on a substrate, and the row shift register and column shift register that drive the gate electrode group and source electrode group are formed in the process of forming each layer of transistors that make up the pixel. or are formed on the same substrate by the same process, or the semiconductor integrated circuit chip is mounted on the substrate directly or by enclosing it in a package, or a crimping method using a conductive rubber connector or a film. It is constructed in the external drive circuit connected to the board using a thermocompression bonding method using a flexible connector. R1+'l
+R&* −−−−RN is the output of the row shift register, Mix , Mix , Mix , −−−
--MiN is the coordinate (il i) + (il 2L (i, a) of the corresponding one column of pixels arranged in a matrix
, -1---(i, M) data waveform of the pixel electrode, Vil, VG2. VG3. ------
ViN is the voltage waveform between the corresponding liquid crystal display pixel drive electrodes, Vo is the electrode potential of the opposing substrate, and ■ is the one-side electrode potential of the display potential storage capacitor.

"I r R1+ R1+ ------R11 is a pulse having a potential of VG so as to sequentially turn on the transistors in the corresponding 1st, 2.3゜-----Nth row. Source bus Data is transmitted to the pixels in each column of the corresponding row while the VG potential is applied, and is accumulated in the display potential storage capacitor, and when the row signal becomes O potential, the pixel data is held at that potential.

In this example, Rs * Rt + RI+ −−−−−
A period during which a signal is applied to sequentially turn on the transistors of the RH gate electrode group w,; w', and R1*''
l + R1+ --- Period I in which the transistors of the gate electrode group of Rli are commonly turned off and vO + vl changes
I;li! ', Mls, Mil, Mix
, -------The pixel data of Min is W and W',
The electrode potentials V and Vb of the opposing substrate are symmetrically reversed, and 2 and E' are also symmetrically reversed. This means that Vis, Via, Via, -
------ViN ``'If you look at Q, the transistor is turned on with W, the voltage between the liquid crystal display pixel drive electrodes is set, and the next W'
The signal for the period until the transistor turns on at , and its W
This means that the signal during the period from when the transistor is turned on at '' and the voltage between the liquid crystal display pixel drive electrodes is set until the transistor is turned on at the next W has a symmetrical AC waveform.

Data from Va to Vb is applied to the source bus using W, and is transmitted to the pixel electrode when the transistor is turned on.

When the transistor is turned off, its potential is held and becomes Vc at E.

(2) After 1 changes, the potential from Vb to 2Vl)-va is held for a period of time until the transistor turns on at W'.

Similarly, at W', data from Va to vb, which is inverted with respect to the previous data at W with reference to the electrode potential of the opposing substrate, is added to the source bus, and when the transistor is turned on, it is transmitted to the pixel electrode. When the transistor turns off, that potential is held, and after Vc and VI change in the opposite direction to the previous E at B', the potential is held from 2Va-Wb to Va for a period of time until the transistor turns on at the next W. Ru. Therefore, the gate potential that turns off the transistor is from Va to v
b source bus data and 2Va-vb to 2Vb-V
a no ii! Since the transistor is turned off according to the data of the electrode of the il element, the voltage is applied in the negative direction as seen from the potential of the source and drain of the transistor, and the potential becomes 0 potential. This is the number of embodiments using N-channel transistors. P
In the channel transistor, the potentials in the embodiment of FIG. 4 are given a single symbol, and the potential relationship is established taking into consideration the above-mentioned points. Also, Vll, Via, Via, ------V
The voltage between IN liquid crystal display pixel drive electrodes is as an absolute value:
The voltage is within lv'b-Val, and gradation display is performed by controlling the voltage applied to the liquid crystal display pixels. When the electrode potential of the opposite substrate changes from Va to vb, the one-side electrode potential of the display potential storage capacitor of the liquid crystal display pixel changes from Ve to Ve.
”(Vb-Va) and have the same amount of potential change, but typically the values are close to each other within a range of 100mV, and it is not possible to obtain a clear image as in the case of equal values. A plurality of these one-side electrodes are connected in common for each row, and the electrodes are drawn out in a stripe shape at the edge of the substrate, and each row is further connected at the edge of the substrate to give a common potential. If the electrode is connected to the electrode of the counter substrate by a transfer electrode, 76e*7a, the number of types of driving voltages for the image display device is reduced, and the embodiment of FIG. 4 is further simplified.

In this way, when changing the electrode potential of the counter substrate, the present invention makes the electrode potential of a plurality of commonly connected one side electrodes of the display potential storage capacitors of the liquid crystal display pixels equal to or close to the amount of change in the electrode potential of the counter substrate. 5, the voltage between the liquid crystal display pixel drive electrodes is maintained before and after the change, thereby realizing an image display device using a novel AC drive method.

Furthermore, the present invention includes the modifications and variations described below.

A plurality of commonly connected one side electrodes of display potential storage capacitors can be connected or shared with adjacent or nearby gate electrodes, and the gate electrode potential that turns off the transistor corresponds to changes in the electrode potential of the opposing substrate. The signal potential is selected so as to ensure that the off-state of the transistor is maintained at that time.

The period E during which the electrode potential Vc of the counter substrate and the one-side electrode potential V of the display potential storage capacitor change is 1.2.3°----
After dividing the Nth row into appropriate groups and applying a gate signal that sequentially turns on the transistors of multiple rows, R1
+R1+ R1+ ------- It is inserted as appropriate within the period W during which the RN signal is being applied. There can be a plurality of periods in which vc+vl changes between w and w', and the number can be different between w and 'w', but as a signal of the potential between liquid crystal display pixel drive electrodes, It is selected to be symmetrically inverted at w and w'.

Also, the periods during which VQ and V change are 1, 2, 3, . '−
----H can be selected within the period when the transistors in any one row are on. In pixels whose transistors are on, data is simultaneously stored in the pixel, and in pixels where other transistors are off, pixel data is converted based on the principle shown in FIG.

Source bus data, that is, a signal that is input into the pixel when the transistor is on, and the electrode potential of the opposing substrate is V.
If the lowest voltage at time a is Vf and the highest voltage is Vg, then the data of the pixel electrode when the electrode potential of the opposing substrate is Va is V.
a≦Vf<Vg.

When the electrode potential of the opposite substrate is vb, vb-(Vg-Va
)<Vb-(Vf-Va)≦vb, and Vg<
You can choose either vb. In addition, the data of the pixel electrode when the electrode potential of the counter substrate is Va is Vf < Vg ≦V
a When the electrode potential of the opposite substrate is vb, vb≦vb+
(Va-Vg)<Vb+ (Va-Vf), and further V
f < Va < Vg, Vb − (Vg − Va)
It is also possible to set <Vb<Vb+(Va −Vf).

Multiple electrodes on one side of the display potential storage capacitor of the liquid crystal display pixels are connected in common for each column, and the electrodes are drawn out in a stripe shape at the edge of the substrate, and each column is further connected at the edge of the substrate and connected in common. A configuration is adopted in which a potential is applied, and this one-sided electrode can be connected to an electrode on a counter substrate by a transfer electrode. As a result of the above, the rows and columns of one-sided electrodes of the display potential storage capacitors of all pixels can be commonly connected.

From a driving perspective, the electrodes on the counter substrate are divided according to the columns of pixels, and the transistors in each row are turned on one after another at the same or close timing to the electrodes on one side that are commonly connected to each column of display potential storage capacitors. In accordance with the timing, the electrodes on the opposing substrate and the electrodes on one side, which are connected in common, are moved so that the amount of signal change is equal to or close to that, and the signal that enters the pixel electrode when the transistor is turned on changes Va, for each frame. W
b are taken alternately, and the signals input to the electrodes of the opposing substrate and one electrode of the display potential storage capacitor are inverted signals with reference to Va and Vb, and AC driving can be performed. Furthermore, one side electrode of the display potential storage capacitor commonly connected for each column is connected to the column electrode of the counter substrate, and 1.2.
3. ---- Divide the Nth row into appropriate groups, set the signal that the transistor turns on and enters the pixel electrode to the selected potential of Va and Vb for each group, and then divide the signal into the next frame. can be set to the selected potentials of Vb and Va for each group.

The display potential storage capacity uses the gate insulating film of the transistor, the glabellar insulating film of the source bus/gate bus, or the insulating film formed for capacitance as a dielectric, and the electrodes are the electrodes of each layer of gate, source, and drain, and the liquid crystal. A display pixel drive electrode or an electrode formed for capacitance can be used, and the material is a dielectric with 5ins 181
sN4. A'l on the electrode, such as A11OS, Ta1Oa, etc.
, Ni, Or.

Mo, Ta, n*os, Snow, etc. are used.

In the electrode of the counter substrate, the conductive film can be divided as necessary, and a color filter can be formed adjacent to or near the conductive film to provide a multicolor image display device. That is, on a counter substrate such as a glass film,
To obtain a transmissive full-color image display device by forming three primary color filters of red, green, and blue, having a structure in which a conductive film is placed close to the filter layer on the liquid crystal side, and applying a light source from behind. I can do it.

In addition to screen printing the three primary color inks, the color filter is formed using a three-layer structure consisting of a green-sensitive emulsion layer, a red-sensitive emulsion layer, and a blue-sensitive emulsion layer with a thin intermediate layer mainly made of gelatin interposed therebetween. A color-forming layer is formed on a counter substrate, and a three-primary color filter of red, green, and evening can be formed by developing and developing the layer with light of cyan, magenta, and yellow, which are complementary colors of the three primary colors. In order to apply this light, in addition to obtaining a color original plate such as a high-magnification color film formed in a predetermined pattern in advance with a camera and photographing it in a reduced size, one pixel of one primary color filter is used to generate the color of the filter using a pattern generator. It can be created by applying complementary color light corresponding to the primary color, step-and-repeat, and then forming another primary color in the same manner.

In addition, in the same manner as above, a color negative layer having a three-layer structure consisting of a blue-sensitive emulsion layer, a green-sensitive emulsion layer, and a red-sensitive emulsion layer with a thin intermediate layer interposed therebetween was formed on the substrate, and the three primary colors red, green, and A color negative substrate is created by exposing it to real light and developing it to develop complementary colors of cyan, magenta, and yellow.A three-layer structure is created in which a green-sensitive emulsion layer, a red-sensitive emulsion layer, and a blue-sensitive emulsion layer are interposed through a thin intermediate layer. By applying white light using the color negative substrate as a filter and developing it on the counter substrate on which the color positive layer has been formed, three colors of red, green, and blue are formed.
A primary color filter can be formed. in this case,! In addition to batch exposure at the same magnification using an exposure device such as a sphere aligner, a negative substrate on which the pattern has been enlarged in advance is reduced and exposed using an exposure device such as a gloziection type mask aligner, and the pattern group is step-and-repeat. A filter covering the entire surface can be formed.

If the color filter layer is made of two continuous stripes of one color in the row or column direction (row stripe filter! or column stripe filter), and the filters are formed in order of color in the column or row direction, and among these stripe filters, Each time a transistor is turned on for each row, a corresponding color signal is introduced from the source path to the electrode of the pixel. In addition to the 1 frame = 1 color frame configuration in which the three primary colors are sequentially applied to the pixel electrodes row by row, the rows are selectively driven and one primary color signal is applied to the pixel electrodes (injected into the next frame) in one frame period. By inserting another Ii color number into the pixel electrode in each frame period, it is possible to drive with a 3-frame-1-2-frame configuration.In the case of a column stripe filter, each time a transistor is turned on for each row, In addition to the 1 frame-1 power 2-frame configuration in which color signals of three primary colors are input from the source path of each column to the pixel electrode, one primary color signal is input from the source path of the corresponding column each time a transistor is turned on for each row. After driving for one frame with another primary color signal in the erased data state by inputting it to the pixel electrode, another primary color can be driven for one frame in the same way, resulting in a 3-frame-1 color frame configuration. .Also, set a certain row to a red/green repeating filter,
If the next row is a repeating green/blue filter, and then the next row is a repeating red/green filter, in addition to having 1 frame = 1 color frame configuration as described above, 2 to 4 color frames can be configured in the same combination. The frame can have a one-color frame configuration.

By the way, in the case of forming the above-mentioned force 2 on a film or the like which is an extremely thin counter substrate, a color image display device is obtained by forming the filter including a protective layer on one side and forming electrodes on the other side. be able to.

Further, in the present invention, the transistor is made of amorphous silicon,
Polycrystalline silicon, single crystal silicon, tellurium, 0(is
It can be constructed from a compound semiconductor such as e, etc., or a laser annealed semiconductor as described above, and in the case of a transistor made of polycrystalline silicon, single crystal silicon, etc., the shift is performed by a complementary connection circuit of a P-channel transistor and an N-channel transistor. Registers and logic circuits can be formed on the same substrate together with transistors constituting pixels.

In an image display device in which 0clSθ is used as a semiconductor layer of a transistor constituting a pixel, 0eLBe and a transistor whose semiconductor layer is made of tellurium are provided in the periphery, so that an N-channel Odeθ transistor and a P-channel 're
) Complementary connection circuits consisting of transistors can be formed on the same substrate in the same manner as above. The present invention is not limited to this example, and transistors having various combinations of semiconductor layers can be selected as the P-channel transistor and the N-channel transistor.

In addition to the transmission type described above, the present invention can also be applied to a reflection type display system, and provides a high quality image display device due to its simple structure.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of one pixel of an image display device. Figure 2 is an equivalent circuit of Figure 1 - pixel configuration. FIG. 3 is a diagram showing the driving principle of pixels of the image display device of the present invention. FIG. 4 shows the timing diagram of the embodiment of the image display device of the present invention.
chart. 1...Transistor 2...Display potential storage capacity 3...Liquid crystal display pixel drive electrode 4...Liquid crystal 5...Gate electrode 6...Source electrode (fm) 2mm (31m) For bud 4/ 'Ql '8t V 2 Procedural Amendment (September 1982) - Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office on the day of the present Relationship with the patent applicant's case Address of the patent applicant: 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Name (0
04) Asahi Glass Co., Ltd. 6. Number of inventions increased by amendment None 7. Subject of amendment 8. Contents of amendment (1) "Transistor" on page 1, page 1, line 7 of the specification is amended to "transistor." (2) Correct the J that enters the [ electrode on page 12, line 13 of the specification] and one side electrode of the display potential storage capacitor to the J that enters the [ electrode. (3) Page 12, line 15 of the specification, “...can be done.Furthermore,...” can be changed to “...can be done.” At this time, the signal input to one side electrode of a plurality of commonly connected display potential storage capacitors continues to be changed so as to be equal to or close to the amount of change in electrode potential of the opposing substrate throughout each claim. Furthermore, it is corrected to ``...''. (4) Page 15, line 15 of the specification [and 1 after J in this]
Add line j to figure-plane 1 through Nχl i2 i3 V to bud 4) Conquer

Claims (1)

[Claims] α) When displaying is performed using a liquid crystal sandwiched between a substrate on which a plurality of transistor elements are formed and a counter substrate on which a conductive film is formed, and the electrode potential of the counter substrate is changed, An image display characterized by changing the voltage of a plurality of commonly connected one side electrodes (X position) of a display potential storage capacitor of a liquid crystal display pixel so as to be equal to or close to the amount of change in electrode potential of a counter substrate. 2. The image display device according to claim 1, wherein the plurality of commonly connected one-side electrodes are electrodes drawn out in a stripe shape at the end of the substrate for each row. (8) The image display device according to claim 1, wherein the plurality of commonly connected one-side electrodes are electrodes drawn out in a stripe shape at the end of the substrate for each column. (Ship) The image display device according to any one of claims 1 to 3, characterized in that an electrode on one side is connected to an electrode on a counter substrate.