JP3069930B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device for displaying images and the like.

[0002]

2. Description of the Related Art Liquid crystal display devices that perform display using the orientation of liquid crystal have been used to display simple numbers and symbols such as early clocks and calculators, but recently to high-definition images such as televisions. In particular, in the case of a liquid crystal display device, a small device such as a portable television is expected because the screen can be made thin.

[0003] The first requirement for mobile devices such as portable televisions is that they be lightweight. In electrical equipment, a power source such as a battery required for driving the power source often occupies most of the weight, and it is a very important factor that power consumption is as small as possible and the power source can be driven for a long time with a low-capacity power source.

However, in the case of a conventional liquid crystal display device using a TN liquid crystal, in order to prevent a phenomenon called sticking peculiar to a liquid crystal panel and to enhance reliability, a potential applied to a pixel is inverted at regular intervals. Was normal. Normally, the TN liquid crystal is driven at 0 to 5 V. In order to perform this inversion, ± 5 V is applied to the common electrode having a constant potential.
That is, a signal having an amplitude of 10 V must be input, and the power consumption is doubled. As a step to solve such a problem, for example, as disclosed in JP-A-58-49989 and JP-A-60-163091, by inverting the potential of the counter electrode to positive or negative. Driving means in which the amplitude is suppressed to half.

[0005]

According to the above-mentioned prior art, although power consumption can be certainly reduced, all means for controlling the potential of the counter electrode are provided on the substrate on the pixel electrode side. In addition, since it is common to the control means of the gate of the transistor of the drive circuit, a large number of wirings are required between the upper and lower substrates, the manufacturing process is complicated, the yield is low, and the reliability as a device is lowered.

[0006]

SUMMARY OF THE INVENTION The present invention is a liquid crystal display device which solves the above-mentioned problems. That is, the present invention, the distance
Active matrix substrate (609)
And counter electrode substrate (610), and sealed in the gap between the substrates
Liquid crystal display device having a liquid crystal (605),
The active matrix substrate has multiple rows and multiple columns.
The plurality of pixel electrodes (603) arranged along
A transistor (104) connected and arranged for each pole;
Scan line drive circuit by connecting transistors in common for each row
Connect to (101) and connect and display in common for each column
Active matrix connected to line drive circuit (102)
A counter circuit, and the counter electrode substrate has a
For each row, a plurality of independent and parallel to the scanning line
A counter electrode (606) and a gate connected to each counter electrode.
Via a voltage switch (111) composed of a transistor
Voltage of opposite polarity (V _{C +} , V _C- )
Potential control means (110, 103) for applying any of
And a liquid crystal display device comprising:

In the present invention, the potential control means for the counter electrode, specifically, a shift register, a T flip-flop, and a voltage changeover switch in an embodiment described later are provided on the counter electrode side substrate, so that two substrates are provided. The number of wires between them can be minimized. In addition, by dividing the counter electrode in parallel to the scanning line and inverting each potential for each row or each frame, it is possible to drive with the power consumption of the effective value as in the related art.

The potential control means according to the present invention and the transistors provided in each pixel are not particularly limited.
A bulk transistor formed on a single-crystal Si substrate and a transmission-type polycrystalline or amorphous Si transistor, which have been used in a conventional reflection type, are preferably used, and preferably a single-crystal Si thin film is formed on a transparent substrate. A TFT (thin film transistor) is used. In addition, a conventional drive circuit for other capacitors and the like and a method for forming these can be suitably used.

FIG. 6 is a schematic sectional view of a main part of a liquid crystal display device of the present invention. This figure is an example of a transmissive liquid crystal display device.
The switching element uses a single-crystal Si transistor, and the driving circuit uses a polycrystalline Si transistor. In the figure, 601 is an insulating layer, 602 is a transparent electrode (pixel capacitance), 603 is a pixel electrode, 604 and 604 'are alignment control films for aligning liquid crystal, 605 is a liquid crystal layer, 606 is a counter electrode, and 607 is polycrystalline. Si transistor, 609 is an active matrix substrate, 610 is a counter electrode substrate, 6
11 is a single crystal Si transistor.

[0010]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Embodiment 1 FIG. 1 shows an equivalent circuit of a first embodiment of the present invention. 1 in the figure
Reference numeral 01 denotes a shift register for driving a scanning line, 102 denotes a shift register for driving a display line, 103 denotes a shift register for driving a counter electrode, and shift registers 101 and 102 are provided on a pixel electrode side substrate, and shift register 103 is a counter electrode. It is formed on the side substrate. 104, a transistor for switching a pixel electrode; 105, a pixel capacitance; 106, a liquid crystal capacitance; 107, a sampling transistor;
Is a sampling capacity, 109 is a reset transistor,
110 is a T flip-flop, 111 is a voltage switch, and 112 is a transfer transistor.

The operation of this embodiment will be described with reference to the timing chart shown in FIG.

Φ _HCK is a clock signal for determining sampling of a video signal of pixels arranged in a horizontal direction (one scanning line). The shift register 102 operates according to φ _HCK , and φ _HL1 , φ _HL2 , φ _HL3 〜 are sequentially output.
The sampling transistor 107 corresponding to the period when this pulse is “H” is turned on, and the Video signal is accumulated in the sampling capacitor 108. During the 1H period, the above operation is performed, and signals for one scanning line are accumulated in all sampling capacitors.

Next, a pulse is applied to φ _VCK to operate the shift register 101. Thereby the connected gate voltage V _n is "H" in the n-th scanning line, the corresponding transistor 104 is turned on. The shift register 101 is configured such that φ _VCK is in the “H” period during the ON period.

[0015] period of V _n is "H", the following two operations are performed.

[0016] _{φRES is set} to “H”, the reset transistor 109 is turned on, and the potentials of the pixel capacitor 105 and the liquid crystal capacitor are set to _VRES . Next, φ _{RES is set} to “L”, the reset transistor 109 is turned off, φ _{T is set} to “H”, and the Video signal for one scanning line stored in the sampling capacitor 108 is applied to the n-th scanning line. The pixel capacitance 105 and the liquid crystal capacitance 106 through the corresponding transistor 104
Write to.

The above is the operation during the 1H period,
By repeating this for the number of scanning lines (rows), the entire panel can be driven.

FIG. 3 shows the potentials V _{C1 to} V _C3 of the counter electrodes.
The Video signal input and a line shows the first column of the pixel electrode potential V _11.

V _{C1 to} V _C3 are shifted by 1H and inverted every frame. The Video signal is also inverted every frame in accordance with the switching of the counter electrode potential. Thus, the first row, first column pixel electrode potential V ₁₁ corresponds to the V _C1. Inversion of the counter electrode potential is performed in the reset period of V _11.

Embodiment 2 FIG. 4 shows an equivalent circuit of a second embodiment of the present invention, and FIG. 5 shows a timing chart thereof. In the first embodiment,
Although the potential of the common electrode is inverted every frame, in this embodiment, the connection of the voltage changeover switch 111 is alternately arranged every other row, and the common electrode potentials of the nth row and the (N + 1) th row are in opposite phases. In this way, driving is performed while inverting the potential for each row.

Embodiment 3 FIG. 7 shows an embodiment in which a metal electrode serving also as a light-shielding layer is provided on a part of the counter electrode of the liquid crystal display device of the present invention to support color display. FIG. 7A is a plan view of the counter electrode,
(B) is a sectional view.

In the figure, reference numerals 701 and 701 'denote opposing electrodes which are usually made of transparent ITO. Reference numerals 702 and 702 'denote metal electrodes, which also serve as light-shielding layers, and are made of W or Al. 703, 703 'are color filters, 704
Denotes an insulating film, 705 denotes a glass substrate, and 706 denotes an alignment control film. In this embodiment, by providing a low-resistance metal electrode to be used as an auxiliary electrode of the counter electrode and as a light-shielding layer, it is possible to blacken the background of a color image and tighten the image.

Embodiment 4 FIG. 8 shows another embodiment in which a metal electrode is provided on a part of the counter electrode to serve as an auxiliary electrode and a light-shielding layer, similarly to the third embodiment. In the present embodiment, since the space between the opposing electrodes is completely shielded from light, a higher light shielding effect can be obtained than in Embodiment 3.

In the figure, reference numerals 801 and 801 'denote counter electrodes, and 802
802 "are metal electrodes, 803 and 803 'are color filters, 804 is an insulating film, 805 is a glass substrate, 806
Is an alignment control film.

[0025]

As described above, in the liquid crystal display device of the present invention, the power consumption is suppressed low by dividing the counter electrode in parallel with the scanning line and inverting the control electrode provided on the counter electrode side. The reliability of the device is improved by reducing the number of wires between the substrates as it is. Further, by providing a metal electrode for the divided opposing electrodes, a color image can be improved and resistance can be reduced.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit of a first embodiment of the present invention.

FIG. 2 is a timing chart of the first embodiment of the present invention.

FIG. 3 is a timing chart of the first embodiment of the present invention.

FIG. 4 is an equivalent circuit of a second embodiment of the present invention.

FIG. 5 is a timing chart of a second embodiment of the present invention.

FIG. 6 is a sectional view of a main part of an example of the liquid crystal display device of the present invention.

FIG. 7 is a plan view and a sectional view of a main part of a third embodiment of the present invention.

FIG. 8 is a plan view and a sectional view of a main part of a fourth embodiment of the present invention.

[Explanation of symbols]

 101 to 103 shift register 104 transistor 105 pixel capacitance 106 liquid crystal capacitance 107 sampling transistor 108 sampling capacitance 109 reset transistor 110 T flip-flop 111 voltage switch 112 transfer transistor 601 insulating layer 602 transparent electrode 603 pixel electrode 604, 604 'orientation control film 605 Liquid crystal layer 606 Counter electrode 607 Transistor 608 Transparent substrate 609 Active matrix substrate 610 Counter electrode substrate 611 Transistor 701, 701 'Transparent electrode 702, 702' Metal electrode 703 Color filter 704 Insulating film 705 Glass substrate 706 Alignment control film 801, 801 ' Transparent electrode 802-802 "Metal electrode 803 Color filter 804 Insulating film 805 Glass substrate 806 Orientation control film

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/133 G02F 1/1368 G09F 9/30 G09G 3/36

Claims (5)

(57) [Claims] 1. Active matrices spaced apart from each other
Substrate (609), counter electrode substrate (610), and
Liquid crystal table having liquid crystal (605) sealed in gaps between substrates
Display device, wherein the active matrix substrate comprises
A plurality of pixel electrodes (6) arranged along a number of rows and a plurality of columns
03) and a transistor connected and arranged for each pixel electrode
(104), and the transistors are commonly connected for each row.
And connected to the scanning line driving circuit (101), and for each column
Do not connect them in common and connect them to the display line drive circuit (102).
The above-mentioned counter electrode substrate having an active matrix circuit
Are independent of each other in parallel with the scanning line for each row of the pixel electrodes.
A plurality of opposing electrodes (606) divided into
Voltage switch consisting of transistors connected to
The opposite electrodes have opposite polarities through the
Potential control means for applying one of the voltages (V _{C +} , V _C- )
(110, 103) . 2. The method according to claim 1, wherein the voltage switch (111) is a polycrystalline S
The liquid crystal according to claim 1, which is an i-transistor (607).
Display device. 3. A transistor connected and arranged for each pixel electrode
Is a single crystal Si transistor (611).
3. The liquid crystal display device according to 2. 4. A method according to claim 1, further comprising:
Is a voltage (V) applied to each counter electrode for each frame. _{C +} ,
V _C- 4. The method according to claim 1, wherein the polarity is reversed.
Liquid crystal display device. 5. An active matrix substrate comprising :
Transistor consists of pixel electrode, liquid crystal and counter electrode
A pixel capacitor (105) is connected in parallel with the liquid crystal capacitor.
The liquid crystal display device according to claim 1.