JP3283855B2 - Projection display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention specifically relates to a video signal transmitted from a terrestrial television station, a satellite television station, a cable television station, or a separately provided television video recorder (video deck, laser disk, magneto-optical disk, etc.). We propose a device to display.

[0002]

2. Description of the Related Art Conventionally, as a device for specifically displaying a video signal transmitted from a terrestrial television station, a satellite television station, a cable television station, or a separately provided television video recording device (video deck, laser disk, magneto-optical disk, etc.). In the prior art, a method of emitting an electron beam in a vacuum tube called a cathode ray tube or a CRT to emit a fluorescent screen as an object has been adopted.

[0003] Initially, the diagonal of the display body was 12 to 14 inches, but recently, due to the demands of the world, the size of 20 inches has come to just over 30 inches.

In the case of a 30-inch diagonal, the depth is about 30 inches, and the thickness of the glass forming it has also exceeded 1 cm in order to maintain strength. As another device, a method of enlarging and displaying a high-luminance cathode ray tube with an optical system and projecting it on a screen has been proposed, and is used for an object having a large display area. FIG. 1 shows an outline of the configuration.

[0005]

In the case of a television receiver using a cathode ray tube, if the display surface exceeds 30 inches, the total weight exceeds 100 kg. It is difficult to place heavy objects exceeding 100 kg in ordinary households unless the location is limited. In addition, it is difficult to move the weight by human power when the layout is changed or the like, which has been an obstacle to the spread to general households.

To solve the problem, a projection-type television receiver has been proposed to solve the problem. However, there is a limit in improving the brightness of a high-brightness CRT, which is the basis of the TV receiver. Had become. For this reason, not only is the screen dark but also enlarged by an optical system, so that the contrast ratio in the front is high, but the contrast ratio in an oblique direction is very inferior to that of the CRT method. However, this method is one of the solutions to the problem because the weight is only about 50% of the CRT method. Projection TV 1 of FIG.
Is a CRT or liquid crystal display device 4, a tuner 4,
It comprises an optical system 3, a reflector 2, and a screen 6. The present invention is shown in FIG.
And a liquid crystal display device indicated by reference numeral 4 in FIG.

In recent years, an embodiment in which a thin film transistor type liquid crystal panel using amorphous silicon is used as a base display body instead of a cathode ray tube has been often proposed. The weight is about 30% less than that of the cathode ray tube method, which has become one of the factors that help spread it to general households. However, the display brightness is still lower than that of the cathode ray tube method, and studies are being conducted to increase the intensity of the light source. However, when the intensity of the light source is increased, when the thin film transistor is turned off due to a rise in the temperature of the liquid crystal panel and light irradiation. It is a reality that satisfactory display cannot be performed due to the decrease in the resistance value in the above. FIG. 2 shows a conventional active array. Also, for simplicity of description, it is shown in a 2 × 2 matrix arrangement. A plurality of gate lines G _1, G ₂ and a plurality of data lines D _1, D ₂
Are arranged orthogonally, and a pixel display element is provided at the intersection of the matrix. This pixel display element is a liquid crystal unit 10
2 and the TFT unit 101. A signal is applied to each pixel from the peripheral circuits 106 and 107, and a predetermined pixel is selectively turned on or off to perform display.

However, when these liquid crystal display devices are actually manufactured and displayed, the output of the TFT, that is, the voltage _VLC of the input to the liquid crystal (referred to as the liquid crystal potential) is often "1" (High). It does not become "1" (High) when it should be, and does not become "0" (Low) when it should become "0" (Low).
This occurs because the characteristics of the switching element for applying a signal to the pixel, that is, the TFT 101 have no symmetry. In other words, this is because the state of charge and the state of discharge to the pixel electrode have a difference in electrical characteristics. And the liquid crystal 102
Is inherently insulating in its operation.
When 01 is off, the liquid crystal potential (V _LC ) is in a floating state.
Since the liquid crystal 102 is equivalently a capacitor, _VLC is determined by the electric charge stored therein. May become the charge liquid is a relatively small resistance R _LC, the presence of dust or ionic impurities Li - click or, also the gate insulating film of the TFT pinholes - there when R _GS occurs by Le Charge leaks from the _{VLC and VLC} is in an incomplete state. Therefore, in a liquid crystal display device having 200,000 to 5,000,000 pixels in one panel, there is a problem that a high yield cannot be achieved.

In an active liquid crystal display device,
It is extremely important to keep the liquid crystal potential at the same level as the initial value during one frame to maintain a predetermined level. However, in reality, there are many defects and it is not always the case. In addition, in driving a liquid crystal or the like, when a voltage applied to the liquid crystal is biased to either + or-due to a signal to be applied, electrolysis or the like occurs, and the liquid crystal material is decomposed and denatured so that display can be sufficiently performed. In such a case, the applied signal is converted into an alternating current so that the voltage applied to the liquid crystal material is not biased. However, the alternating signal is very complicated.

[0010] The present invention solves the above-mentioned problems and increases the current margin, that is, the response speed. Further, the potential of the pixel in each pixel, that is, the liquid crystal potential
_{The LC} is fixed to "1" and "0" sufficiently stably so that the level does not drift during one frame.

[0011]

[ MEANS FOR SOLVING THE PROBLEMS] The present invention provides one pixel
One pixel electrode and two N-channel thin film transistors
Has a transistor and two P-channel thin film transistors
Display device, the two P-channel thin film transistors
The source or drain of the transistor is connected to the first signal line.
Of the two N-channel thin film transistors
The source or the drain is connected to the second signal line,
The two P-channel type thin film transistors and the two
The gate electrode of the N-channel type thin film transistor
Connected to a signal line, the two N-channel thin films
Transistor and two P-channel thin film transistors
Star is covered with an organic resin film for flattening, the flattening
Said one pixel electrode is provided on the use organic resin film, wherein
One of the two N-channel thin film transistors and the two
One of the two P-channel type thin film transistors has a first complementary
Type thin film transistor, the two N-channel type
The other of the thin film transistors and the two P-channel thin films
The other of the membrane transistors is a second complementary thin film transistor
Constitute the first complementary thin film transistor and the
The second complementary thin film transistor is connected to the one pixel electrode.
A display device which is connected. Departure
The display device according to claim 1, wherein the signal waveform is applied to the third signal line during a period in which the signal waveform is applied to the pair of first and second signal lines. Complementary thin film transistor (hereinafter referred to as C / TFT)
Drives, Ru on or Ofusu the display of the pixel.

The present invention provides a signal line having a matrix configuration on a substrate and a complementary thin film transistor in which a P-channel thin film transistor and an N-channel thin film transistor are formed in a complementary manner on each pixel electrode. One of the output sides is connected to the pixel electrode, the other is connected to the first signal line of the pair of signal lines having the matrix configuration, and the gate of the complementary thin film transistor is connected to the first of the signal lines having the matrix configuration. A first substrate provided with an electric circuit connected to the second signal line, and a second substrate provided with electrodes and leads on the substrate, a liquid crystal composition exhibiting ferroelectricity and at least an initial state of the liquid crystal composition. Displaying a television image on at least a liquid crystal panel sandwiching means for performing the alignment in the above. Receiver.

A signal line having a matrix configuration is provided on a substrate, and a complementary thin film transistor having a complementary structure of a P-channel thin film transistor and an N-channel thin film transistor is provided for each pixel electrode. To the pixel electrode,
An electric circuit in which the other one is connected to a first signal line of a pair of signal lines having the matrix configuration, and a gate of the complementary thin film transistor is connected to a second signal line of the signal line having the matrix configuration. The first substrate provided and the second substrate provided with electrodes and leads on the substrate sandwiched at least a liquid crystal composition exhibiting ferroelectricity and at least a means for performing initial alignment of the liquid crystal composition. A television receiver, which shines light from behind a liquid crystal panel and projects the light passing through the panel onto a screen in front or an object in its place via an optical system to display a television image.

A signal line having a matrix structure is formed on a substrate, and a complementary thin film transistor having a complementary structure of a P-channel thin film transistor and an N-channel thin film transistor is provided on each pixel electrode. To the pixel electrode,
An electric circuit in which the other one is connected to a first signal line of a pair of signal lines having the matrix configuration, and a gate of the complementary thin film transistor is connected to a second signal line of the signal line having the matrix configuration. The first substrate provided and the second substrate provided with electrodes and leads on the substrate sandwiched at least a liquid crystal composition exhibiting ferroelectricity and at least a means for performing initial alignment of the liquid crystal composition. The red, green, and blue lights are applied to each panel from the rear of the three liquid crystal panels, and the light passing through each panel is formed on one screen via an optical system, and the front screen or a substitute for the front screen is formed. A television receiver that projects a television image on an object.

A signal line having a matrix configuration is provided on a substrate, and a complementary thin film transistor having a complementary structure of a P-channel thin film transistor and an N-channel thin film transistor is provided for each pixel electrode. To the pixel electrode,
An electric circuit in which the other one is connected to a first signal line of a pair of signal lines having the matrix configuration, and a gate of the complementary thin film transistor is connected to a second signal line of the signal line having the matrix configuration. The first substrate provided and the second substrate provided with electrodes and leads on the substrate sandwiched at least a liquid crystal composition exhibiting ferroelectricity and at least a means for performing initial alignment of the liquid crystal composition. Red, green, and blue lights are alternately applied to the panel from behind one liquid crystal panel, and the light that has passed through the panel is projected on a screen in front or an object in its place via an optical system to display a television image. Characteristic TV receiver. A signal line having a matrix configuration on a substrate and a complementary thin film transistor in which a P-channel thin film transistor and an N-channel thin film transistor are formed in a complementary manner on each pixel electrode are provided, and one of the input and output sides of the complementary thin film transistor is connected. The other one of the pair of signal lines having the matrix configuration is connected to the first electrode of the pair of signal lines having the matrix configuration, and the gate of the complementary thin film transistor is connected to the second signal line of the signal line having the matrix configuration. A first substrate provided with a connected electric circuit and a second substrate provided with electrodes and leads on the substrate form a polymer resin and a nematic liquid crystal or a polymer resin and a cholesteric liquid crystal or a polymer resin and a smectic liquid crystal or Polymer liquid crystal and nematic liquid crystal or polymer liquid crystal and cholesteric liquid crystal The liquid crystal panel at least one sandwich a polymer liquid crystal and smectic liquid crystal, television set and displaying the television image. Then, a signal line having a matrix configuration on the substrate and a complementary thin film transistor in which a p-channel thin film transistor and an n-channel thin film transistor are formed in a complementary manner on each pixel electrode are provided, and one of the input / output sides of the complementary thin film transistor is connected The other one of the pair of signal lines having the matrix configuration is connected to the first electrode of the pair of signal lines having the matrix configuration, and the gate of the complementary thin film transistor is connected to the second signal line of the signal line having the matrix configuration. A first substrate provided with a connected electric circuit and a second substrate provided with electrodes and leads on the substrate form a polymer resin and a nematic liquid crystal or a polymer resin and a cholesteric liquid crystal or a polymer resin and a smectic liquid crystal or Polymer liquid crystal and nematic liquid crystal or polymer liquid crystal and cholesteric liquid crystal Light is applied from the back of the liquid crystal panel that sandwiches at least one of the polymer liquid crystal and the smectic liquid crystal, and the light that passes through the panel is projected on a screen in front or an object in its place via an optical system to display a TV image. TV receiver.

A signal line having a matrix configuration is provided on a substrate, and a complementary thin-film transistor in which a P-channel thin film transistor and an N-channel thin film transistor are formed in a complementary manner on each pixel electrode is provided. To the pixel electrode,
An electric circuit in which the other one is connected to a first signal line of a pair of signal lines having the matrix configuration, and a gate of the complementary thin film transistor is connected to a second signal line of the signal line having the matrix configuration. The first substrate provided and the second substrate provided with electrodes and leads on the substrate provide a polymer resin and a nematic liquid crystal or a polymer resin and a cholesteric liquid crystal or a polymer resin, a smectic liquid crystal or a polymer liquid crystal and a nematic liquid crystal. Red, green, and blue light was applied to each panel from the back of three liquid crystal panels that sandwiched at least one liquid crystal or polymer liquid crystal and cholesteric liquid crystal or polymer liquid crystal and smectic liquid crystal, and passed through each panel. The light is formed on a single screen via an optical system, and the light is applied to the screen in front of the screen or an alternative object. TV receiver, characterized in that project a TV image.

A signal line having a matrix configuration is provided on a substrate, and a complementary thin film transistor in which a P-channel thin film transistor and an N-channel thin film transistor are formed in a complementary manner on each pixel electrode is provided. To the pixel electrode,
An electric circuit in which the other one is connected to a first signal line of a pair of signal lines having the matrix configuration, and a gate of the complementary thin film transistor is connected to a second signal line of the signal line having the matrix configuration. The first substrate provided and the second substrate provided with electrodes and leads on the substrate provide a polymer resin and a nematic liquid crystal or a polymer resin and a cholesteric liquid crystal or a polymer resin, a smectic liquid crystal or a polymer liquid crystal and a nematic liquid crystal. Red, green, and blue light are alternately applied to the panel from the back of one liquid crystal panel that sandwiches at least one liquid crystal or polymer liquid crystal and cholesteric liquid crystal or polymer liquid crystal and smectic liquid crystal. , A television image is projected on a screen in front or an object in its place via an optical system. It is a television receiver.

The structure of the liquid crystal panel according to the present invention will be described below. As a configuration of the liquid crystal display device according to the present invention, one pixel may be configured by connecting two or more C / TFTs to one pixel. One more
One pixel may be divided into two or more, and one or more C / TFTs may be connected to each.

FIG. 3 shows a typical example of the configuration of the display device of the present invention.
4 and 5 show circuit diagrams. FIG. 6 shows an example of an actual pattern layout (arrangement diagram).
These are shown in FIGS. For simplicity of explanation, here 2
The description will be made by taking a × 2 matrix configuration as an example. 3 of FIG.
In the example of the × 2 matrix, the gates of the NTFT and PTFT are connected to each other, further connected to the third signal line 3 or 4 in the Y-axis direction, and the common output terminal of the C / TFT is connected to the liquid crystal 15. I have. This type of complementary thin film transistor (C / TFT) is called an inverter type and is suitable for driving pixels of ferroelectric liquid crystal. In this case, a type in which the positional relationship between the NTFT and PTFT is interchanged is called a buffer type, and a dispersion type liquid crystal, for example, a polymer resin and a nematic liquid crystal, or a polymer resin and a cholesteric liquid crystal, or a polymer resin and a smectic liquid crystal or It is suitable for an element for driving a pixel electrode of a liquid crystal display device using a liquid crystal composed of liquid crystal and nematic liquid crystal or polymer liquid crystal and cholesteric liquid crystal or polymer liquid crystal and smectic liquid crystal.

For example, in the case of the inverter type, in FIG. 3, the input terminal (10 side) of the PTFT is connected to the first signal line 5 or 6 of a pair of signal lines in the X-axis direction,
The input terminal (20 side) of T is connected to the second signal line 8 or 7 of the pair of signal lines in the X-axis direction. In the case of the buffer type, since the positional relationship between PTFT and NTFT may be changed in FIG. 3, the signs of P and N shown in FIG. 3 may be changed symmetrically.

In such a configuration (FIG. 3), as shown in FIG. 9, V _DD is applied to the pair of first signal lines 5, and
When the ON signal waveform is applied to the third signal line 3 while V _SS is being applied to the signal line 8 of the first embodiment, the liquid crystal potential (V _LC ) 14 is changed to the voltage V _LC applied to the first signal line. Become _DD . That is, only the PTFT is in contact, and the NTFT is in an insulated state.

During a period in which the pair of the first signal line 5 and the second signal line 8 have no potential, the liquid crystal potential (V _LC ) 14 has no potential regardless of the third signal line 3. .

Further, V _{DD is applied to the} pair of first signal lines 5.
During the period when V _SS is applied to the second signal line 8,
When the ON signal waveform is not applied to the signal line 3, the liquid crystal potential (V _LC ) 14 changes to the voltage V _SS applied to the second signal line.
Becomes That is, only the NTFT is in contact and the PTFT is insulated.

As described above, since the liquid crystal potential (V _LC ) 14 can be fixed to V _DD or V _SS , no floating occurs.

The counter electrode 16 has an offset voltage V
_{The OFFSET} is applied, and the voltage actually applied to the liquid crystal 15 has three values of V _DD + V _OFFSET , V _OFFSET or V _SS + V _OFFSET . In the driving method of the present invention, the on / off of the liquid crystal driving can be arbitrarily changed by changing the offset voltage V _OFFSET applied to the counter electrode. Also, since the threshold for actually driving the liquid crystal differs depending on the liquid crystal material, an arbitrary threshold can be adjusted only by changing the offset voltage V _OFFSET in order to match the value of the liquid crystal. it can.

In the driving of the liquid crystal, if the voltage applied to the liquid crystal is biased to either + or-depending on the applied signal, electrolysis or the like occurs, and the liquid crystal material is decomposed and denatured, and the display is sufficiently performed. In this case, the applied signal is converted into an alternating current so that the voltage applied to the liquid crystal material is not biased. However, according to the driving method of the present invention, the polarity of the offset voltage V _OFFSET applied to the counter electrode is changed. Only by inverting the logic of the selection signal applied to the data signal line and the data signal line, an AC signal can be generated very easily.

In the example shown in FIG. 4, PTFT 13, NTFT 22 and second C / TFT constituting the first C / TFT
Are connected in common to the third signal line 3 in the Y direction by using the four gate electrodes PTFT 24 and NTFT 25
The PTFT 13 and PTFT 24 input terminals are shared, and the NTFT 22 and NTFT 25 input terminals are shared with the first signal line 5 in the X direction and connected to the second signal line 8 in the X direction. The outputs of the two C / TFTs are shared and connected to a pixel electrode 17 which is one electrode of one liquid crystal 15. Thus, two NTFTs or two PTFTs
Even if either one of them leaks to some extent, the pixel is driven because it is in phase.

FIG. 5 shows that, in one pixel 23, two pixel electrodes 17, 26 and the C / T
In this example, two FTs are provided. The gate electrode of the two C / TFTs is made common, and the first input is performed. The input of each NTFT and each PTFT of each C / TFT is connected to the first signal line 5 and the second signal line 8.
It is connected to. Thus, one of the two pixels in one pixel does not become inoperative due to a defect such as a leak of the TFT. Further, even if the operation is delayed, the other operates normally, so that a defect is less noticeable in the matrix configuration operation. Although the C / TFTs shown in FIGS. 4 and 5 are all of the inverter type, it goes without saying that they may be of the buffer type.

[0029]

Embodiment 1 In this embodiment, a liquid crystal display device using a ferroelectric liquid crystal (FLC) will be described using a liquid crystal display device using a circuit configuration as shown in FIG. 3, that is, an inverter type circuit configuration. FIG. 6 shows an actual arrangement of electrodes and the like corresponding to this circuit configuration. For simplification of description, only portions corresponding to 2 × 2 are described. FIG. 9 shows an actual drive signal waveform. For the sake of simplicity, the description will be made using signal waveforms in the case of a 4 × 4 matrix configuration.

First, a method for manufacturing a liquid crystal display device used in this embodiment will be described with reference to FIGS. FIG.
In (A), a silicon oxide film as a blocking layer 51 is formed on a glass 50 that can withstand a heat treatment of inexpensive 700 ° C. or less, for example, about 600 ° C., such as quartz glass, by using a magnetron RF (high frequency) sputtering method.
It is made to a thickness of 0 °. The process conditions were a 100% oxygen atmosphere, a film formation temperature of 15 ° C., an output of 400 to 800 W, and a pressure of 0.5 Pa. The film formation rate using quartz or single crystal silicon as a target was 30 to 100 ° / min.

A silicon film was formed thereon by LPCVD (low pressure gas phase), sputtering or plasma CVD. When formed by the reduced pressure gas phase method, the temperature is 1
450-550 ° C lower by 00-200 ° C, for example 530 ° C
CVD of disilane (Si ₂ H ₆ ) or trisilane (Si ₃ H ₈ )
The film was supplied to the apparatus to form a film. Reactor pressure is 30 ~ 300
Pa. The deposition rate was 50-250 ° / min.
Threshold voltage (Vt) between NTFT and PTFT
In order to control substantially the same as in h), boron may be added at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ cm ⁻³ during film formation using diborane.

When the sputtering method is used, the back pressure before the sputtering is set to 1 × 10 ⁻⁵ Pa or less, and single crystal silicon is used as a target in an atmosphere in which hydrogen is mixed with 20 to 80% of argon. For example, argon was 20% and hydrogen was 80%.
The film formation temperature was 150 ° C., the frequency was 13.56 MHz, the sputter output was 400 to 800 W, and the pressure was 0.5 Pa.

When a silicon film is formed by the plasma CVD method, the temperature is, for example, 300 ° C., and monosilane (SiH ₄ ) or disilane (Si ₂ H ₆ ) is used. These were introduced into a PCVD apparatus, and a high-frequency power of 13.56 MHz was applied to form a film.

The coatings formed by these methods are:
Oxygen is 5 × 10^{twenty one}cm^-3The following is preferred. This acid
If the element concentration is high, it is difficult to crystallize and the thermal annealing temperature
High or long thermal annealing times must be used.
If the amount is too small, the lamp is turned off by the backlight.
Current increases. Therefore 4 × 10¹⁹~ 4 × 10 ^{twenty one}
cm^-3Range. Hydrogen is 4 × 10²⁰cm^-3And silicon 4
× 10^{twenty two}cm^-3Was 1 atomic%. Also,
To promote crystallization for source and drain
The oxygen concentration is 7 × 10¹⁹cm^-3Below, preferably 1 × 10¹⁹
cm^-3The following is the channel formation of the TFT that constitutes the pixel
5 x 10²⁰~ 5 × 10
^{twenty one}cm^-3You may add so that it may become. At that time, peripheral circuits
Since the constituent TFTs are not irradiated with light,
Less carrier contamination and higher carrier mobility
Is effective for high frequency operation.
You.

Next, a silicon film in an amorphous state is
After fabrication to a thickness of ~ 5000mm, for example 1500mm, 4
Medium-temperature heat treatment in a non-oxide atmosphere at a temperature of 50 to 700 ° C. for 12 to 70 hours, for example, 600 hours in a hydrogen atmosphere.
It was kept at a temperature of ° C. Since a silicon oxide film having an amorphous structure is formed on the surface of the substrate under the silicon film, no specific nucleus is present in this heat treatment, and the whole is annealed uniformly. That is, it has an amorphous structure at the time of film formation, and hydrogen is simply mixed therein.

By the annealing, the silicon film shifts from an amorphous structure to a highly ordered state, and a part of the silicon film exhibits a crystalline state. In particular, a region having a relatively high order in a state after the formation of silicon is particularly likely to be crystallized to be in a crystalline state. However, since the silicon existing between these regions is bonded to each other, silicon mutually pulls each other. When measured by laser Raman spectroscopy, a single crystal silicon peak 522 is obtained.
A peak shifted to a lower frequency side than cm ⁻¹ is observed. Its apparent particle size is 50 to 5 when calculated from the half width.
Although it is a microcrystal with a size of 00Å, there are actually a large number of regions with high crystallinity and a cluster structure, and a semi-amorphous structure film in which each cluster is bonded to each other by silicon (anchoring). Could be formed.

As a result, the coating is substantially grain bowed.
The state that can be said that there is no dali (hereinafter referred to as GB)
Present. Carrier anchored between each cluster
So-called GB
Higher carrier mobility than clearly existing polycrystalline silicon
Become. That is, hole mobility (μh) = 10 to 200 cm ^Two
/ VSec, electron mobility (μe) = 15-300 cm^Two
/ VSec.

On the other hand, when the film is polycrystallized by high-temperature annealing at 900 to 1200 ° C. instead of annealing at medium temperature as described above, segregation of impurities in the film occurs due to solid phase growth from nuclei. , GB contain many impurities such as oxygen, carbon, and nitrogen, and have a high mobility in the crystal. However, a barrier is formed in the GB to hinder the movement of carriers there. As a result, a mobility of 10 cm ² / Vsec or more cannot be easily obtained. That is, in this embodiment, a silicon semiconductor having a semi-amorphous or semi-crystalline structure is used for such a reason.

On this, a silicon oxide film was formed as a gate insulating film to a thickness of 500 to 2000 {for example, 1000}. This was made under the same conditions as those for forming the silicon oxide film as the blocking layer. During the film formation, a small amount of fluorine may be added to fix the sodium ions.

Thereafter, 1 to 5 × 10 ²¹ cm of phosphorus is placed on the upper side.
^-3 silicon film or molybdenum (Mo), tungsten (W), MoSi ₂ or
A multilayer film with WSi ₂ was formed. This was patterned using a second photomask to obtain FIG. PTFT
The gate electrode 9 for NTFT and the gate electrode 19 for NTFT were formed. For example, a channel length of 10 μm, 0.2 μm of silicon as a gate electrode, and 0.1 μm of molybdenum thereon.
It was formed to a thickness of 3 μm. In FIG. 12C, a photoresist 57 is formed using a photomask,
Boron was added to the TFT source 10 and the drain 12 at a dose of 1 to 5 × 10 ¹⁵ cm ⁻² by ion implantation. Next, as shown in FIG. 12D, NTFT was formed using a photomask. Source 20 for NTFT,
Phosphorus was added as the drain 18 by ion implantation at a dose of 1 to 5 × 10 ¹⁵ cm ⁻² .

These steps were performed through the gate insulating film 54. However, in FIG. 12B, the gate electrodes 55, 5
6 may be used as a mask to remove silicon oxide on the silicon film, and then boron and phosphorus may be directly ion-implanted into the silicon film.

Next, annealing was performed again at 600 ° C. for 10 to 50 hours. The source 10 and the drain 12 of the PTFT and the source 20 and the drain 18 of the NTFT were formed as P ⁺ and N ⁺ by activating impurities. Channel formation regions 21 and 11 are formed below the gate electrodes 9 and 19 as semi-amorphous semiconductors.

In this way, a C / TFT can be manufactured without applying a temperature to 700 ° C. or more in all steps, even though it is a self-aligned system. Therefore, it is not necessary to use an expensive substrate such as quartz as a substrate material, and this is a process very suitable for the large pixel liquid crystal display device of the present invention.

In this embodiment, the thermal annealing is performed as shown in FIG.
(D) was performed twice. However, the annealing in FIG. 12 (A) is omitted due to the required characteristics, and both are omitted from the annealing in FIG. 12 (D).
The manufacturing time may also be reduced by using a tool. FIG.
In (A), a silicon oxide film was formed on the interlayer insulator 65 by the above-described sputtering method. This silicon oxide film may be formed by an LPCVD method, a photo CVD method, or a normal pressure CVD method. For example, it was formed to a thickness of 0.2 to 0.6 μm, and then a window 66 for an electrode was formed using a photomask. Further, aluminum is formed on the entire surface by sputtering, and leads 71 and 72 and contacts 67 and 68 are formed using a photomask. Then, the surface is flattened with an organic resin 69 for flattening, for example, a translucent polyimide resin. It was formed and the electrode drilling was performed again using a photomask.

As shown in FIG. 13B, in order to connect the two TFTs to a complementary structure and connect the output terminals thereof to the electrodes of one pixel of the liquid crystal device as a transparent electrode, ITO (indium oxide) is formed by sputtering. A tin oxide film). This was etched using a photomask to form the pixel electrode 17. This ITO film was formed at room temperature to 150 ° C., and was achieved by oxygen at 200 to 400 ° C. or annealing in air.

Thus, PTFT 22 and NTFT
13 and a transparent conductive film electrode 70 as a pixel electrode were formed on the same glass substrate 50. The characteristics of the obtained TFT are P
TFT has a mobility of 20 (cm ² / Vs) and Vth of -5.9.
In (V), the mobility of NTFT was 40 (cm ² / Vs) and Vth was 5.0 (V).

It goes without saying that the above manufacturing method is exactly the same whether it is of the buffer type or the inverter type.

One substrate for a liquid crystal device manufactured according to the above-described method and another substrate provided with a transparent electrode over the entire surface of a glass substrate were bonded to each other to form a liquid crystal cell. A ferroelectric liquid crystal composition was sealed therein. In FIG.
The PTFT 13 is provided at the intersection between the first scanning line 5 and the data line 3, and the PTFT for other pixels is similarly provided at the intersection between the first scanning line 5 and the data line 4. Meanwhile NT
The FT is provided at the intersection of the second scanning line 8 and the data line 3. An NTFT for another pixel is provided at the intersection of the adjacent first scanning line 6 and data line 3. A matrix configuration (in this case, an inverter type) using such a C / TFT is provided. PTFT1
3 is connected to the first scanning line 5 via a contact 69 at the input end of the drain 10, and the gate 9 is connected to the data line 3 on which a multilayer wiring is formed. The output terminal of the source 12 is connected to the electrode 17 of the pixel via the contact 67.

On the other hand, the NTFT 22 has an input terminal of the drain 20 connected to the second scanning line 8 via a contact, a gate 21 connected to the data line 3, and an output terminal of the drain 18 connected to the second scanning line 8 via a contact 68 similarly to the PTFT. It is connected to the pixel electrode 17. Thus, the pixel 17 made of the transparent conductive film and the PTFT 1 are interposed (inside) between the pair of scanning lines 5 and 8.
One pixel was constituted by 3 and the C / TFT including the NTFT 22. By repeating such a structure horizontally and vertically, a 2 × 2 matrix is enlarged to 64
A liquid crystal display device having large pixels such as 0 × 480 and 1280 × 960 can be obtained.

The feature here is that one pixel has two TFs.
Since T is provided in a complementary configuration, the pixel electrode 17 is fixed at three values of the liquid crystal potential _VLC .

In the case of this embodiment, X _1a X _1b ,
X _2a X _2b , X _3a X _3b , and X _4a X _4b each function as a pair of scanning signal lines in the X direction. Also, Y ₁ , Y ₂ , Y ₃ , Y
Reference numeral ₄ functions as a data line in the Y direction. FIG.
AA, AB... DD in FIG. 4 mean the address of the pixel at the corresponding position. In FIG. 14, the inverter type configuration is adopted as shown in FIG. 14 where P, N, PTFT and NTFT are shown, but it goes without saying that the buffer type is obtained by exchanging the PTFT and NTFT. .

In the display of such a 4 × 4 configuration, FIG.
FIG. 9 shows a timing chart of a signal waveform, a liquid crystal potential, and a potential difference actually applied to the liquid crystal corresponding to four pixels at addresses AA, AB, BA, and BB shown in FIG. In FIG. 9, the horizontal axis indicates time. One frame at time T
The interval between 1 and T2 is divided into four, and four pairs of scanning lines are sequentially scanned to apply a scanning signal. In the figure, only X _1a , X _2a , X _3a , and X _4a are described. However, X _1b , X _2b , X _3b , and X _4b are actually X _1a , X _2a , X _3a , and X _4b.
The same waveform having a different polarity from that of _4a is applied. Also, Y
A data signal as shown in FIG. 9 is applied to the ₁ , Y ₂ , Y ₃ , and Y ₄ lines, and only the AA pixel is selected and turned on or off from time T1 to T2. That is, from T ₁ to t
By applying a data signal to the data lines Y ₁ during _1,
During this time, a voltage exceeding the threshold is applied to the liquid crystal of the AA pixel, and the liquid crystal is driven. At this time, the offset voltage is applied to the opposing electrode of the liquid crystal display device. In FIG. 9, the same signal waveform is applied from the next time T2 to T3, and AA is displayed.

Next, from time T3 to T4 and from T4 to T5, a signal that does not select any of the four pixels is applied.
Further, from time T5 to T6, a signal for selecting the AA pixel is applied again.

Next, from time T6 to T8, a signal obtained by inverting the logic of the signal applied to the data line is applied, and the counter electrode has an offset having a polarity different from that of the signal applied from time T1 to T6. A voltage is applied and an alternating signal is applied to the liquid crystal. With this alternating signal, the charges that have been positively biased between times T1 and T6 can be canceled. That is, of the signal which has been applied from time T2 to _{T4, Y 1, Y 2,} Y 3, inverts the logic of Y _4-wire, i.e. interchanged selection signal and a non-selection signal,
By exchanging the offset voltage of the opposing electrode, the AA pixel is selected in the first frame of the time T2 to T4, and the AC signal which does not select the four pixels is applied in the second frame of the time, thereby driving the liquid crystal. It became possible. This makes it possible to easily cancel the charge remaining in the pixel.

As described above, according to the driving of the present invention, a very simple pulse signal can be applied to a data line and a pair of scanning lines to perform a liquid crystal display.

In this embodiment, when one screen is displayed by applying drive signals of a plurality of frames to the liquid crystal for one display screen, the number of selection signals to be applied to a specific pixel is reduced from the total number of frames. Thus, gradation display can be easily performed.

In the present invention, an organic film is used as the alignment film, and in order to increase the switching speed, the operating voltage is set to ± 20 to ± 25 V, and the cell interval is set to be as thin as 1 to 3 μm.

When the liquid crystal display device shown in this embodiment is used, light transmitted through the liquid crystal display panel is illuminated from the rear by illuminating the liquid crystal display panel with light from the rear of the television receiver or the liquid crystal display panel. It is possible to obtain a liquid crystal projector or the like that projects on a screen or the like in front through the system. Further, as the semiconductor of the TFT used in this embodiment, materials other than those used in this embodiment can be used.

[0059]

[Embodiment 2] This embodiment is an example in which an inverter type circuit is formed by using a liquid crystal display having the structure shown in FIGS. Also in this embodiment, a C / TFT composed of PTFT and NTFT, which are basic structures, is used.
Is exactly the same as in Example 1. 4 and 7 are the same as those described in the first embodiment with reference to FIGS.

As is clear from FIG. 7, the scanning line 3 of the Y line is disposed at the center, and the portion of the pair of data lines sandwiched between the first data line 5 and the second data line 8 is defined as one pixel. 23. One pixel is one pixel of one transparent conductive film
7 and two PTFTs 13, 24 and two NTFTs
22 and 25 are connected to two C / TFTs. The gate electrodes are all connected to scan line 3 and two P
The TFT is connected to a first data line 5 and the two NTFTs are connected to a second data line 8. These two C / T
Even if one of the FTs is defective due to a leak between the gate electrode and the channel formation region, it can be operated as a pixel. FIG. 10 shows an example of a timing chart when the present embodiment is driven.

The feature here is that one pixel has two C / Ts.
By providing the FT, the pixel electrode 17 is fixed at the liquid crystal potential _VLC of three values.

In the case of this embodiment, a mixture of a photocurable epoxy-modified acrylic resin and a nematic liquid crystal is formed on a first substrate to a thickness of 10 μm by a printing method, and then the second substrate is superposed under reduced pressure. Then, the cells were formed by irradiating ultraviolet rays from below while applying a pressure of ² kg / cm ² . FIG. 15 shows the cross-sectional structure. FIG. 15 shows a glass substrate 150, a liquid crystal phase 154, a pixel electrode 17, and an upper electrode 15 as a counter electrode.
5, for example, a signal line 15 corresponding to the signal line 8 in FIG.
2, for example, a signal line 15 corresponding to the signal line 6 in FIG.
1, and the lower substrate 153 having the circuit configuration shown in FIG.
Consisting of By using the liquid crystal display device shown in FIG. 15 for the portion 4 of the projection television shown in FIG. 1, a high-performance projection television can be obtained.

[0063]

Embodiment 3 This embodiment corresponds to FIG. 5 and FIG. One pixel is composed of two C / TFTs and two pixels. That is, PTFT13, NTFT22
Liquid crystal pixel electrode 1 connected to the output of a C / TFT
7 and C / T composed of other PTFT 24 and NTFT 25
The pixel electrode 81 of the liquid crystal connected to the output of the FT constitutes one pixel 23. Pixels 17 and 81 correspond to combined pixel 23 that forms one pixel.

With this configuration, even if one of the pixels does not operate, the other pixel operates and the probability of generating a non-operational pixel when the colorization is performed can be reduced. In addition, what is not described here is the same as that described in Examples 1 and 2. FIG. 11 shows an example of a timing chart when the present embodiment is driven.

As a display medium in this specification, a transmission type liquid crystal display device or a reflection type liquid crystal display device can be used. The liquid crystal material that can be used is TN of the prior art.
Liquid crystal, FLC liquid crystal, dispersion type liquid crystal, and polymer type liquid crystal can be used. In addition, an ionic dopant is added to a guest-host type or dielectric anisotropic type nematic liquid crystal and an electric field is applied to apply the electric field to a nematic liquid crystal and a mixture of the cholesteric liquid crystal and a nematic phase and a cholesteric phase. A phase change liquid crystal which causes a phase change between the liquid crystal and the liquid crystal and realizes a transparent or cloudy display can also be used. In addition to the liquid crystal, for example, a so-called electrophoretic display dispersion system in which pigment particles having different colors are dispersed in an organic solvent colored with a dye can be used. Also, in this case, it is better to make the C / TFT a buffer type circuit configuration, as described above.

[0066]

As described above, the configuration of the present invention makes it possible to reduce the size of a conventional television receiver using a cathode ray tube.
The weight was reduced by about 70%. Further, according to the structure of the present invention, since the liquid crystal potential is not floating, stable display can be performed. Also, since the driving capability of the C / TFT as the active element is high, the operation margin can be expanded, and the peripheral driving circuit can be made simpler, so that the display device can be downsized and the manufacturing cost can be reduced. There is. In addition, high driving capability can be exhibited with very simple signals to the three signal lines and the counter electrode.

Further, even if a defective TFT is present in a part, the output is in-phase, so that the compensation can be performed to some extent.

Further, in order to prevent the liquid crystal material from being electrolyzed, an AC signal driving which is indispensable for driving the liquid crystal is performed by C / TF.
This was achieved simply by inverting the logic of the signal applied to the T gate signal line and inverting the polarity of the offset voltage applied to the counter electrode.

[Brief description of the drawings]

FIG. 1 shows a conventional projection type television receiver.

FIG. 2 is a circuit diagram of a conventional liquid crystal electro-optical device using a single channel thin film transistor.

FIG. 3 is a circuit diagram of a liquid crystal electro-optical device using a complementary thin film transistor according to the present invention.

FIG. 4 is a circuit diagram of a liquid crystal electro-optical device using a complementary thin film transistor according to the present invention.

FIG. 5 is a circuit diagram of a liquid crystal electro-optical device using a complementary thin film transistor according to the present invention.

FIG. 6 is a configuration diagram of a liquid crystal electro-optical device using a complementary thin film transistor according to the present invention.

FIG. 7 is a configuration diagram of a liquid crystal electro-optical device using a complementary thin film transistor according to the present invention.

FIG. 8 is a configuration diagram of a liquid crystal electro-optical device using a complementary thin film transistor according to the present invention.

FIG. 9 is a driving chart according to the present invention.

FIG. 10 is a driving chart according to the present invention.

FIG. 11 is a driving chart according to the present invention.

FIG. 12 shows a process of a complementary thin film transistor according to the present invention.

FIG. 13 shows a process of a complementary thin film transistor according to the present invention.

FIG. 14 is a circuit diagram according to the present invention.

FIG. 15 is a configuration diagram of a liquid crystal electro-optical device using a complementary thin film transistor according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 Source of P-channel TFT 11 Channel of P-channel TFT 12 Drain of P-channel TFT 13 P-channel TFT 18 Drain of N-channel TFT 21 Channel of N-channel TFT 20 Source of N-channel TFT 9 P-channel Gate electrode of N-type TFT 19 Gate electrode of N-channel TFT 17 Pixel electrode 15 Liquid crystal

Continuation of the front page (56) References JP-A-62-91993 (JP, A) JP-A-64-32235 (JP, A) JP-A-63-96636 (JP, A) JP-A-49-77537 (JP) , A) JP-A-1-156725 (JP, A)

Claims (1)

(57) [Claims] 1. One pixel electrode, one pixel electrode, two pixels
In the N-channel type thin film transistor and a display device having two P-channel thin film transistor, the source and the drain of said two P-channel thin film transistor is connected to a first signal line, the source of the two N-channel type thin film transistor Or, the drain is connected to a second signal line, and the two P-channel thin film transistors and the two
The gate electrode of the N-channel type thin film transistor
Connected to a signal line, the two N-channel thin film transistors and the two
The P-channel thin film transistor is covered with an organic resin film for planarization, wherein the planarizing organic resin film one pixel electrode is provided, one before and the two N-channel type thin film transistor
One of the two P-channel thin film transistors is the first
A complementary thin film transistor is formed, and the other of the two N-channel thin film transistors and the other
The other of the two P-channel thin film transistors is the second
Forming a complementary thin film transistor, the first complementary thin film transistor and the second complementary thin film transistor;
A display device, wherein a thin film transistor is connected to the one pixel electrode .