JP2003222890A - Liquid crystal display - Google Patents

Abstract

(57) [Problem] To provide an active matrix type liquid crystal display device having high light use efficiency and capable of high quality display regardless of the state of ambient light. A switching element includes first and second switching elements.
Switching elements 5a and 5b. The auxiliary capacitance element has a reflection auxiliary capacitance element and a transmission auxiliary capacitance element. The amplitude of each gate signal input to the first and second gate lines 3a and 3b, the parasitic capacitance between each gate-drain electrode of the first and second switching elements 5a and 5b, The capacitance of each liquid crystal layer 29 of the pixel electrode 2a and the transmission pixel electrode 2b and the capacitance of each of the reflection auxiliary capacitance element and the transmission auxiliary capacitance element are set to the reflection pixel electrode potential generated at the time of switching. The amount of voltage shift from the source signal voltage and the amount of voltage shift of the transmission pixel electrode potential from the source signal voltage are set to be the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device having reflective pixel electrodes and transmissive pixel electrodes.

[0002]

2. Description of the Related Art A liquid crystal display device is characterized by its thinness and low power consumption, and is utilized in office automation equipment such as word processors and personal computers, portable information equipment such as electronic notebooks, and camera devices equipped with a liquid crystal monitor. Widely used for body-shaped VTRs and the like. The direct-view liquid crystal display device includes a transmissive liquid crystal display device using a transparent conductive thin film such as ITO (Indium Tin Oxide) for a pixel electrode and a reflective liquid crystal display device using a reflective electrode such as a metal for the pixel electrode. There is a display device.

The display modes used in the above-mentioned reflective display device include a mode using a polarizing plate such as a TN (twisted nematic) mode and an STN (super twisted nematic) mode which are widely used at present, and a polarizing plate. The phase transition guest-host mode, which can realize bright display because it does not use, has been actively developed in recent years.

Further, the liquid crystal panel of the above liquid crystal display device is
Unlike CRT (cathode ray tube) and EL (electroluminescence) display devices, they do not emit light by themselves. Therefore,
In the case of a transmissive liquid crystal display device, a device provided with a fluorescent tube called a backlight is installed in the back, and a display is performed by transmitting light from the backlight. Further, in the case of a reflective liquid crystal display device, display is performed by reflecting incident light from the surroundings by the reflective electrode.

Since the transmissive liquid crystal display device performs display using a backlight as described above, it is possible to perform bright and high-contrast display without being significantly affected by ambient brightness. it can. However, since the backlight normally occupies 50% or more of the total power consumption of the transmissive liquid crystal display device, the power consumption is increased by providing the backlight. Further, when the ambient light is very bright, for example, in fine weather, the display light appears darker than the ambient light, and the visibility is deteriorated.

On the other hand, the reflective liquid crystal display device does not require a backlight and thus can reduce power consumption, but the brightness and contrast of the display are influenced by the environment of use such as the ambient brightness, and in particular, When the ambient light is dark, there is a problem that visibility is extremely deteriorated.

Therefore, in order to solve the above problems,
Japanese Patent Application Laid-Open No. 7-333598 uses a semi-transmissive reflective film that reflects and transmits incident light with a certain reflectance and a certain transmittance so that both the transmissive display and the reflective display are displayed on a single liquid crystal display. A configuration realized by a panel is disclosed.

However, when the semi-transmissive reflective film is formed of a metal thin film, it is necessary to use a material having a large absorption coefficient, which increases the internal absorption of incident light and causes scattered light that is not used for display. As a result, the efficiency of light utilization deteriorates. Further, in the case where fine holes are formed in the metal thin film in order to control the reflectance and the transmittance of one pixel to obtain the same effect as the semitransparent film, the structure of the metal thin film is too fine. Therefore, it is difficult to control, and it is difficult to produce a film having uniform characteristics.

Therefore, in order to solve the above problems,
In JP-A-11-101992, as shown in FIG. 13, light is efficiently utilized by forming a reflective region 26 made of a metal film and a transmissive region 28 made of a transparent conductive film in the same pixel. A liquid crystal display device which is excellent in productivity is disclosed. Further, in this liquid crystal display device, the optical path lengths of the reflective region and the transmissive region are made uniform by changing the thickness of the liquid crystal in the reflective region and the transmissive region, and the light utilization efficiency is improved.

[0010]

However, a reflective region (reflective pixel electrode) 26 made of a metal film and a transmissive region (transmissive pixel electrode) 28 made of a transparent conductive film are formed in the same conventional pixel as described above. In the liquid crystal display device, since the optimum counter voltage of the reflective region 26 and the optimum counter voltage of the transmissive region 28 are different from each other, as will be described later, a DC bias voltage is always applied to the liquid crystal layer by a deviation from each optimum counter voltage. Will be applied. The optimum counter voltage is D
In order to prevent the deterioration of the liquid crystal due to the application of the C voltage, it is the counter electrode voltage when the voltage of the counter electrode is corrected so that the absolute values of the positive potential and the negative potential applied to the liquid crystal layer become equal. Here, the reason why the optimum opposing voltages are different from each other will be described.

The drain voltage applied to the pixel electrode in each of the regions 26 and 28 does not match the source voltage, and ΔVd obtained from the source voltage at the moment when the gate is closed, for example, by the following equation (1). Only shift.

ΔVd = (ΔVg × Cgd / (Cgd + Clc + Ccs)) (1) Note that the parasitic capacitance between the gate electrode and the drain electrode is Cg.
d, the capacitance of the liquid crystal layer is Clc, the capacitance of the auxiliary capacitance element (auxiliary capacitance) is Ccs, and the gate potential difference is ΔVg.

Further, in the above-mentioned conventional liquid crystal display device, since the thickness of the liquid crystal in the reflective region and the thickness in the transmissive region are different, the capacitance Clc of the liquid crystal layer has different values.
Further, in the above liquid crystal display device, the parasitic capacitance Cgd between the gate electrode and the drain electrode, the auxiliary capacitance Ccs, and the gate potential difference ΔVg are different in each region 26.
28 is the same. Therefore, the shift value of each voltage in the reflection area 26 and the transmission area 28 is different. Therefore, the optimum counter voltage of the reflective region 26 and the optimum counter voltage of the transmissive region 28 are different.

That is, as shown in FIGS. 14A to 14E, the gate potential difference ΔVg (r) of the reflective pixel electrode 26 and the gate potential difference ΔVg (t) of the transmissive pixel electrode 28 are the same. Even if a signal is input, the voltage shift amount (shift amount of the reflection pixel electrode 26) ΔVd (r) of the reflection pixel electrode potential from the source signal voltage and the voltage shift of the transmission pixel electrode potential from the source signal voltage. Since the amount (shift amount of the transmissive pixel electrode 28) ΔVd (t) is different, the optimum counter voltage Vo (r) of the reflective pixel electrode 26 and the optimum counter voltage Vo (t) of the transmissive pixel electrode 28 are different from each other. It will be different. Note that each gate potential difference ΔVg (r) · ΔVg
(T) is the high level voltage Vg of each gate signal
The difference between h (r) · Vgh (t) and the low level voltage Vgl (r) · Vgl (t) of each gate signal.

On the other hand, since the voltage of the counter electrode (not shown) cannot be partially changed in potential, the voltage of the counter electrode, the optimum counter voltage of the reflective region 26 and the optimum counter voltage of the transmissive region 28 are the same. It is not possible to match each voltage at the same time. Therefore, the deviation between the voltage of the counter electrode and the optimum counter voltage of the reflection area 26 and / or the deviation of the voltage of the counter electrode and the optimum counter voltage of the transmission area 28 are always applied to the liquid crystal layer as a DC bias voltage. It will be.

Therefore, when it is used for a long period of time, it causes display defects such as unevenness and blurring. In addition, in a liquid crystal display device used especially as a mobile display device, a low frequency driving method has been proposed in order to suppress power consumption. However, a deviation from each optimum counter voltage between the reflective region and the transmissive region is flicker. It is more likely to be recognized as (flicker), which is also a cause of deterioration in display quality.

The present invention has been made in view of the above-mentioned conventional problems, and its object is
It is an object of the present invention to provide a liquid crystal display device including an active matrix substrate which has high light utilization efficiency and enables high-quality display.

[0018]

In order to solve the above problems, a liquid crystal display device of the present invention has a reflective pixel electrode for performing a reflective display and a transmissive pixel electrode for performing a transmissive display. A plurality of pixel electrodes arranged in a matrix, an auxiliary capacitance element that holds the potential of the pixel electrodes, a source wiring that supplies a source signal, a gate wiring that supplies a gate signal, a source electrode, a gate electrode, and a drain. An active matrix substrate having an electrode and a switching element which is selected by the gate signal and supplies a source signal to the pixel electrode, and an opposing electrode having an opposing electrode opposing the reflective pixel electrode and the transmissive pixel electrode A liquid crystal display device comprising: a substrate; and a liquid crystal layer formed between the active matrix substrate and the counter substrate. Switching element comprises a first switching element and second switching element, the reflective pixel electrode, first through the first switching element 1
Is connected to the gate wiring of
Is connected to the second gate line via the switching element, and the auxiliary capacitance element is a reflection auxiliary capacitance element connected to the reflection pixel electrode, and a transmission auxiliary capacitance connected to the transmission pixel electrode. An amplitude of a gate signal input to the first gate wiring, an amplitude of a gate signal input to the second gate wiring, and a gate electrode and a drain electrode of the first switching element. Between them, the parasitic capacitance between the gate electrode and the drain electrode of the second switching element, the capacitance of the liquid crystal layer between the reflection pixel electrode and the counter electrode, and the transmission pixel. A reflective pixel in which the capacitance of the liquid crystal layer between the electrode and the counter electrode, the capacitance of the reflective auxiliary capacitance element, and the capacitance of the transmissive auxiliary capacitance element occur during switching of the switching element. Is characterized by the voltage shift from the source signal voltage electrode potential, the voltage shift from the source signal voltage of the transmissive pixel electrode potential is set to be the same.

According to the above invention, the reflection pixel electrode is connected to the first gate wiring via the first switching element. Further, a reflection auxiliary capacitance element is connected to the reflection pixel electrode. On the other hand, the transmissive pixel electrode is connected to the second gate wiring via the second switching element. Further, a transmissive auxiliary capacitance element is connected to the transmissive pixel electrode.

Therefore, the amplitude of the gate signal input to the first gate wiring, the amplitude of the gate signal input to the second gate wiring, the gate electrode and the drain electrode of the first switching element, Parasitic capacitance between
The parasitic capacitance between the gate electrode and the drain electrode of the second switching element, the capacitance of the liquid crystal layer between the reflection pixel electrode and the counter electrode, the transmission pixel electrode and the counter electrode, It is possible to individually set the capacitance of the liquid crystal layer, the capacitance of the reflection auxiliary capacitance element, and the capacitance of the transmission auxiliary capacitance element in between.

Here, at the time of switching of the switching element, more specifically, at the moment when the switching element is turned off, the parasitic capacitance between the gate electrode and the drain electrode of the switching element, and the parasitic capacitance between the pixel electrode and the counter electrode. The voltage applied to the pixel electrode by the voltage determined by the relationship between the capacitance of the liquid crystal layer, the capacitance of the auxiliary capacitance element, and the amplitude of the gate signal input to the gate wiring of the switching element is the source signal. Shift from voltage. That is,
When an AC rectangular wave is input to the source wiring, the rectangular wave shifts in the voltage axis direction while the amplitude and phase of the rectangular wave remain the same.

The amount of voltage shift is different between the reflective pixel electrode and the transmissive pixel electrode. There are four reasons why the voltage shift amount is different.

The first reason is that the reflective pixel electrode and the transmissive pixel electrode use different gate wirings, that is, the first gate wiring and the second gate wiring, and therefore each switching element is not always required. This is because it is not necessary to match the amplitudes of the gate signals input to the gate wirings, and in this case, the amplitudes of the gate signals are different.

The second reason is that since the reflective pixel electrode and the transmissive pixel electrode use different switching elements, that is, the first switching element and the second switching element, each switching element is not always required. This is because the parasitic capacitance between the gate electrode and the drain electrode does not match.

The third reason is that the liquid crystal layer between the reflection pixel electrode and the counter electrode and the liquid crystal layer between the transmission pixel electrode and the counter electrode have different thicknesses. And the areas are different, and the capacitances of the liquid crystal layers do not match.

The fourth reason is that the capacitance of the reflection auxiliary capacitance element and the capacitance of the transmission auxiliary capacitance element do not always match due to the structure of the active matrix.

Therefore, in the present invention, the parasitic capacitance between the gate electrode and the drain electrode of the switching element, which determines the shift amount of the voltage, and the capacitance of the liquid crystal layer between the pixel electrode and the counter electrode, The capacitance of the auxiliary capacitance element and the amplitude of the gate signal input to the gate wiring of the switching element are set separately for the reflection pixel electrode and the transmission pixel electrode, and the voltage shift amount is set. Are the same for the reflective pixel electrode and the transmissive pixel electrode.

As a result, the voltage shift amounts of the reflection pixel electrode and the transmission pixel electrode become the same, and the waveform signals having the same shift amount are generated in the reflection pixel electrode and the transmission pixel electrode. can get.

Therefore, the voltage of the central axis along the time axis of the voltage waveform in the reflective pixel electrode and the transmissive pixel electrode after the shift can be used as the voltage of the counter electrode. This makes it possible to match the voltage on the central axis of the voltage waveform of the reflective pixel electrode, the voltage on the central axis of the voltage waveform of the transmissive pixel electrode, and the voltage of the counter electrode.

For example, when an AC rectangular wave is input to the source wiring, the absolute value of the positive potential and the negative potential of the reflection pixel electrode with respect to the counter electrode becomes equal, and at the same time, the transmission with respect to the counter electrode is performed. The absolute values of the positive potential and the negative potential of the pixel electrode for use also become equal.
In the following, the respective optimum counter electrode voltages for the reflective pixel electrode and the transmissive pixel electrode, that is,
The voltage on the central axis along the time axis for each of the above voltage waveforms is taken as the optimum reflection opposing voltage and the optimum transmission opposing voltage. Therefore, in the liquid crystal display device, since the voltage shift amount is the same, the reflection optimum counter voltage and the transmission optimum counter voltage match each other.

As described above, in the liquid crystal display device of the present invention,
The voltage of the counter electrode becomes the optimum counter voltage for reflection and the optimum counter voltage for transmission. Therefore, when the optimum reflection counter voltage and the optimum transmission counter voltage are different, a voltage difference from the counter electrode is always generated, but the liquid crystal display device of the present invention does not. Therefore, a phenomenon in which the deviation between the optimum counter voltage for reflection and / or transmission and the voltage of the counter electrode is a DC bias voltage and is always applied to the liquid crystal layer does not occur.

Therefore, in the liquid crystal display device of the present invention,
It is possible to suppress the occurrence of display defects such as unevenness and haze that occur when the liquid crystal display device is used for a long period of time. Further, the occurrence of flicker can be suppressed. On the other hand, since the reflection pixel electrode and the transmission pixel electrode are used, the light utilization efficiency is improved. Therefore, it is possible to provide a liquid crystal display device that has high light utilization efficiency and enables high-quality display regardless of the state of ambient light.

In the liquid crystal display device of the present invention, the parasitic capacitance between the gate electrode and the drain electrode of the first switching element is Cgd (r),
The capacitance of the liquid crystal layer between the reflective pixel electrode and the counter electrode is set to Cl.
c (r) and the capacitance of the reflection auxiliary capacitance element are C
cs (r), the parasitic capacitance between the gate electrode and the drain electrode of the second switching element is Cgd (t), and the capacitance of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is Clc.
(T), and the capacitance of the transmission auxiliary capacitance element is Cc
s (t), the amplitude of the gate signal input to the first gate wiring is ΔVg (r), and the amplitude of the gate signal input to the second gate wiring is ΔVg (t). ΔVg (r) × Cgd (r) / (Cgd
(R) + Clc (r) + Ccs (r)) = ΔVg (t)
× Cgd (t) / (Cgd (t) + Clc (t) + Cc
It is characterized by satisfying the relation of s (t).

According to the invention, a general voltage shift amount Δ
The following relational expression expressing Vd, ΔVd = ΔVg × Cgd
In / (Cgd + Clc + Ccs), the values of the shift amounts ΔVd of the respective voltages are equal in the reflection pixel electrode and the transmission pixel electrode.

Therefore, in the above-mentioned liquid crystal display device, it is possible to make the optimum reflection opposing voltage and the optimum transmission opposing voltage match.

Further, the liquid crystal display device of the present invention is characterized in that, in the above-mentioned liquid crystal display device, the same gate signal is inputted to the first gate wiring and the second gate wiring.

According to the above invention, the same gate signal is input to the first gate wiring and the second gate wiring.

Therefore, it is not necessary to shift the phase of the gate signal from the first gate wiring and the phase of the gate signal from the second gate wiring. By comparison, the frequency of the gate signal can be halved. Therefore, it is possible to provide a liquid crystal display device capable of high-quality display while reducing power consumption.

In order to solve the above problems, the liquid crystal display device of the present invention is arranged in a matrix having reflective pixel electrodes for performing reflective display and transmissive pixel electrodes for performing transmissive display. A plurality of pixel electrodes, an auxiliary capacitance element that holds the potential of the pixel electrodes, a source wiring that supplies a source signal, a gate wiring that supplies a gate signal, a source electrode, a gate electrode, and a drain electrode, An active matrix substrate having a switching element which is selected by a gate signal and supplies a source signal to the pixel electrode, an opposite substrate having an opposite electrode facing the reflection pixel electrode and the transmission pixel electrode, and the active matrix In a liquid crystal display device including a substrate and a liquid crystal layer formed between the counter substrate, the switching element is It is composed of a first switching element and a second switching element, the reflection pixel electrode is connected to a first gate line via the first switching element, and the transmission pixel electrode is a second switching element. An auxiliary capacitance element connected to the second gate line through an element, the auxiliary capacitance element being connected to the reflection pixel electrode, and the transmission auxiliary capacitance element being connected to the transmission pixel electrode. And occurs at the time of switching the first switching element and the second switching element,
The reflection pixel electrode and the transmission pixel electrode are so arranged that the voltage shift amount of the reflection pixel electrode potential from the source signal voltage and the voltage shift amount of the transmission pixel electrode potential from the source signal voltage become the same. The source signal voltage applied to the reflective pixel electrode via the first switching element and the source signal voltage applied to the transmissive pixel electrode via the second switching element in accordance with each display timing of It is characterized by different.

According to the above invention, the reflection pixel electrode is connected to the first gate wiring via the first switching element. On the other hand, the transmissive pixel electrode has a second
Is connected to the second gate wiring via the switching element. Therefore, the switching timing of each switching element can be different. Also, the source signal voltage when the switching elements connected to the respective pixel electrodes are turned on is changed so that the voltage shift amount of the reflection pixel electrode and the voltage shift amount of the transmission pixel electrode become the same. There is.

Here, at the time of switching of the switching element, more specifically, at the moment when the switching element is turned off, the voltage shifts from the source signal voltage as described above. Also, the amount of voltage shift is different between the reflective pixel electrode and the transmissive pixel electrode due to the above four reasons.

Therefore, in the present invention, the voltage of the source voltage is controlled in advance in consideration of the difference between the voltage shift amount of the reflection pixel electrode and the voltage shift amount of the transmission pixel electrode. Make the shift amount the same.

As a result, the voltage shift amounts of the reflective pixel electrode and the transmissive pixel electrode become the same, and the waveform signals having the same shift amount are generated in the reflective pixel electrode and the transmissive pixel electrode. can get.

Therefore, as described above, the voltage on the central axis of the voltage waveform of the reflective pixel electrode, the voltage on the central axis of the voltage waveform of the transmissive pixel electrode, and the voltage of the counter electrode should be matched. Is possible.

From the above, in the liquid crystal display device of the present invention,
The voltage of the counter electrode may be the optimum counter voltage for reflection and the optimum counter voltage for transmission. Therefore, in the liquid crystal display device of the present invention, a voltage difference from the counter electrode does not occur.

Therefore, in the liquid crystal display device of the present invention,
It is possible to suppress the occurrence of display defects such as unevenness and haze that occur when the liquid crystal display device is used for a long period of time. Further, the occurrence of flicker can be suppressed. On the other hand, since the reflection pixel electrode and the transmission pixel electrode are used, the light utilization efficiency is improved. Therefore, it is possible to provide a liquid crystal display device that has high light utilization efficiency and enables high-quality display regardless of the state of ambient light.

In the liquid crystal display device of the present invention, the parasitic capacitance between the gate electrode and the drain electrode of the first switching element is Cgd (r),
The capacitance of the liquid crystal layer between the reflective pixel electrode and the counter electrode is set to Cl.
c (r) and the capacitance of the reflection auxiliary capacitance element are C
cs (r), the parasitic capacitance between the gate electrode and the drain electrode of the second switching element is Cgd (t), and the capacitance of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is Clc.
(T), and the capacitance of the transmission auxiliary capacitance element is Cc
s (t), the amplitude of the gate signal input to the first gate wiring is ΔVg (r), and the amplitude of the gate signal input to the second gate wiring is ΔVg (t). Further, the difference ΔVs between the source signal voltage applied to the reflection pixel electrode and the source signal voltage applied to the transmission pixel electrode is ΔVs = ΔVg (r) × Cgd
(R) / (Cgd (r) + Clc (r) + Ccs
(R)) − ΔVg (t) × Cgd (t) / (Cgd
It is characterized in that the relationship of (t) + Clc (t) + Ccs (t) is satisfied.

According to the above invention, the shift amount ΔVg (r) × Cgd (r) / (Cgd of the voltage of the reflection pixel electrode is obtained.
(R) + Clc (r) + Ccs (r)) and the shift amount ΔVg (t) × Cgd (t) / of the voltage of the transmissive pixel electrode.
The signal voltage of the source line applied to the reflective pixel electrode and the source signal voltage applied to the transmissive pixel electrode differ by the difference of (Cgd (t) + Clc (t) + Ccs (t).

Therefore, the potential of the reflective pixel electrode after the shift and the potential of the transmissive pixel electrode after the shift coincide with each other due to the difference ΔVs of the source signal voltage. Therefore, in the liquid crystal display device, it is possible to match the optimum reflection opposing voltage and the optimum transmission opposing voltage.

Further, the liquid crystal display device of the present invention is the same as the above liquid crystal display device, in which the thickness of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is the liquid crystal layer between the reflective pixel electrode and the counter electrode. The feature is that the thickness is larger than the layer thickness.

According to the above invention, the optical path length in the liquid crystal layer of ambient light passing back and forth through the liquid crystal layer corresponding to the area of the reflective pixel electrode, and the liquid crystal layer corresponding to the area of the transmissive pixel electrode. The optical path length of the transmitted light passing through the liquid crystal layer can be approximated.

Therefore, it is possible to make uniform the changes in the light characteristics of the liquid crystal layer corresponding to the area of the reflective pixel electrode and the liquid crystal layer corresponding to the area of the transmissive pixel electrode.
Therefore, it is possible to further increase the light utilization efficiency.

Further, the liquid crystal display device of the present invention is the same as the above liquid crystal display device, in which the thickness of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is equal to the liquid crystal layer between the reflective pixel electrode and the counter electrode. It is characterized in that it is twice the thickness of the layer.

According to the above invention, the optical path length in the liquid crystal layer of ambient light passing back and forth through the liquid crystal layer corresponding to the region of the reflective pixel electrode, and the liquid crystal layer corresponding to the region of the transmissive pixel electrode. It is possible to match the optical path length of the transmitted light passing through the liquid crystal layer.

Therefore, it is possible to make the changes in the light characteristics of the liquid crystal layer corresponding to the area of the reflective pixel electrode and the liquid crystal layer corresponding to the area of the transmissive pixel electrode coincide with each other. Therefore, it is possible to further increase the light use efficiency.

Further, in the liquid crystal display device of the present invention, in the above liquid crystal display device, a peripheral portion of the transmissive pixel electrode is superposed by a pair of reflective pixel electrodes via one or more insulating films. It is characterized by that.

According to the above-mentioned invention, since the reflective pixel electrode forming a set is superposed on the transmissive pixel electrode via the insulating film, the area of the reflective pixel electrode is further expanded. As a result, The area of the region including the reflective pixel electrode and the transmissive pixel electrode is increased.

Therefore, the aperture ratio of the entire liquid crystal display device is increased, and the light utilization efficiency can be improved.

Further, in the liquid crystal display device of the present invention, in the above liquid crystal display device, the reflection auxiliary capacitance element is formed by the reflection auxiliary capacitance wiring and the conductive film electrically connected to the reflection pixel electrode. The transparent auxiliary capacitance element is formed by a transparent auxiliary capacitance line and a transparent pixel electrode, and the reflection auxiliary capacitance line and the transparent auxiliary capacitance line are
The reflective pixel electrode and the transmissive pixel electrode forming a pair have the same wiring, and the auxiliary capacitance wiring does not overlap the area of the transmissive pixel electrode where the reflective pixel electrode does not overlap.

According to the above invention, the auxiliary capacitance line used for the auxiliary capacitance of the reflective pixel electrode and the auxiliary capacitance line used for the auxiliary capacitance of the transmissive pixel electrode serve as a common auxiliary capacitance line. Further, the common auxiliary capacitance line does not overlap the region of the transparent pixel electrode used for liquid crystal display.

Therefore, the actual area of the transmissive pixel electrode used for liquid crystal display can be further increased by the area of the auxiliary capacitance wiring. Therefore, the aperture ratio of the entire liquid crystal display device can be further increased, and the light utilization efficiency can be further improved.

Further, in the liquid crystal display device of the present invention, in the above liquid crystal display device, the first gate wiring and the second gate wiring are the same wiring for the pair of the reflective pixel electrode and the transmissive pixel electrode. It is characterized by being.

According to the above invention, the first gate wiring and the second gate wiring are the same wiring in the reflective pixel electrode and the transmissive pixel electrode forming a set, and therefore, one set of reflective pixel is formed. It is possible to reduce the number of gate wirings for the pixel electrode including the electrode and the transmissive pixel electrode from two to one.

Therefore, the pixels can be miniaturized, a liquid crystal display device having a high resolution can be obtained, and at the same time, the production yield of the liquid crystal display device can be significantly reduced.

[0065]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] An embodiment of the present invention will be described with reference to FIGS.
It is as follows.

As shown in FIG. 1, the active matrix substrate 1a of this embodiment has pixel electrodes 2 arranged in a matrix. Further, a gate wiring 3 for supplying a scanning signal and a source wiring 4 for supplying a display signal so as to pass through the periphery of the pixel electrode 2 and be orthogonal to each other.
And are provided.

The gate wiring 3 and the source wiring 4 are formed of a metal film, and a part thereof overlaps the outer peripheral portion of the pixel electrode 2 with the gate insulating film 11 (see FIGS. 2 and 3) interposed therebetween.

In the vicinity of the intersection of the gate line 3 and the source line 4, a thin film transistor (TF) as a switching element for supplying a display signal to the pixel electrode 2 is provided.
T) 5 is provided.

The gate wiring 6 is connected to the gate electrode 6 of the thin film transistor (TFT) 5, and a thin film transistor (TFT) is supplied by a signal input to the gate electrode 6.
5 is drive-controlled. In addition, a thin film transistor (TF
The source wiring 3 is connected to the source electrode 7 of T) 5,
A data signal is input to the source electrode 7.

Further, as a feature of the active matrix substrate 1a of the present embodiment, the pixel electrode 2 is composed of a reflective pixel electrode 2a made of a metal film and a transmissive pixel electrode 2b made of a transparent conductive film. Further, the gate wiring 3, the thin film transistor (TFT) 5, the gate electrode 6, the source electrode 7, the drain electrode 8 and the auxiliary capacitance wiring 12 are provided separately from the reflection pixel electrode 2a and the transmission pixel electrode 2b. Each is individually provided for control.

That is, for the reflective pixel electrode 2a, the reflective gate wiring 3a (first gate wiring), the reflective thin film transistor (TFT) 5a (first switching element), the reflective gate electrode 6a, and the reflective gate electrode 6a. Source electrode 7
a, a reflection drain electrode 8a, and a reflection auxiliary capacitance wiring 12a are provided. Further, for the transmissive pixel electrode 2b, a transmissive gate wiring 3b (second gate wiring) and a transmissive thin film transistor (TFT) 5b (second).
Switching element), a transmissive gate electrode 6b, a transmissive source electrode 7b, a transmissive drain electrode 8b, and a transmissive auxiliary capacitance line 12b.

Next, the above active matrix substrate 1
The sectional structure of the liquid crystal display device using a will be described.

The active matrix substrate 1a is
As shown in FIG. 2 (a cross-sectional view taken along the line AA of FIG. 1), a reflective gate electrode 6 a is provided on the transparent insulating substrate 15, and the reflective gate electrode 6 a is the gate insulating film 1.
Covered by 1. Then, the gate insulating film 1
On top of the semiconductor layer 16 and the doped semiconductor layer 17
And are stacked in this order. Further, in order to cover the doped semiconductor layer 17, ITO (Indium T
in Oxide) and a reflective source electrode 7a and a reflective drain electrode 8a formed of two layers of a metal film and a transparent conductive film.
And are formed.

The source wiring 4 composed of the transparent conductive film and the metal film is connected to the reflection source electrode 7a, and the transparent conductive film and the metal film are formed in the reflection drain electrode 8a. Is connected to the connection electrode 10. The connection electrode 10 is used as the contact hole 9
In the portion contacting the reflective pixel electrode 2a via
Although it has a two-layer structure, it is formed of one layer of the transparent conductive film in other portions.

Further, the reflective pixel electrode 2a is formed on the electrodes 7a and 8a with an interlayer insulating film 18 interposed therebetween. A liquid crystal layer 29 is provided between the reflective pixel electrode 2 a and the counter electrode 14 formed on the counter substrate 13.
Are formed.

Further, on the transparent insulating substrate 15, as shown in FIG. 3 (a sectional view taken along the line BB of FIG. 1), a reflection auxiliary capacitance wiring 12a is provided. A transparent pixel electrode 2b formed of the transparent conductive film is provided on the gate insulating film 11. Here, the connection electrode 10 and the transmissive pixel electrode 2b are respectively provided with the reflective auxiliary capacitance line 12a via the gate insulating film 11.
-It is formed on 12b.

Further, on the transparent insulating substrate 15,
As shown in FIG. 4 (a sectional view taken along the line C-C in FIG. 1), a transparent gate electrode 6b is provided, and the transparent gate electrode 6b is covered with a gate insulating film 11. Then, the semiconductor layer 16 and the doped semiconductor layer 17 are stacked in this order on the gate insulating film 11. Further, a transparent source electrode 7b and a transparent drain electrode 8b formed of two layers of the transparent conductive film and the metal film are formed so as to cover the doped semiconductor layer 17.

Further, the source wiring 4 made of the transparent conductive film and the metal film is connected to the transparent source electrode 7b, and the transparent pixel electrode 2b is connected to the transparent drain electrode 8b. ing.

With the above structure, the drain electrode 8a is formed.
The connection electrode 10 electrically connected to the above forms the reflection auxiliary capacitance element by the auxiliary capacitance wiring 12a and the gate insulating film 11 interposed therebetween. Further, the transparent pixel electrode 2b forms a transparent auxiliary capacitive element by the auxiliary capacitive wiring 12b and the gate insulating film 11 interposed therebetween.

Further, since the transmissive pixel electrode 2b is formed on the gate insulating film 11 as described above, it is directly connected to the transmissive drain electrode 8b, and the reflective pixel electrode 2a and the reflective drain electrode 2b. A component such as a contact hole 9 for connecting with 8a is unnecessary.

The auxiliary capacitance wirings 12a and 12b are formed of a metal film, and the counter substrate 13 is formed by wiring not shown.
Is connected to the counter electrode 14 formed on. Further, the source wiring 4 has a two-layer structure of the transparent conductive film and the metal film in order to provide redundancy for defects such as disconnection.

The active matrix substrate 1a is constructed as described above. Next, a method of manufacturing the active matrix substrate 1a will be described.

First, a reflective gate electrode 6a and a transmissive gate electrode 6b are formed on a transparent insulating substrate 15 such as glass.
A reflection gate wiring 3a and a transmission gate wiring 3b,
Reflection auxiliary capacitance wiring 12a and transmission auxiliary capacitance wiring 1
After 2b and the film are formed by a sputtering method or the like, patterning is performed through a photolithography process.

Next, the gate insulating film 11, the semiconductor layer 16,
The doped semiconductor layer 17 is formed by using the plasma CVD method. Subsequently, a transparent electrode film made of ITO (Indium Tin Oxide) is formed by a sputtering method, and a connection electrode 10 and a transmission pixel electrode 2b are formed through a photolithography process. Further, after forming a metal film by a sputtering method, patterning is performed to form the source wiring 4
And a reflection source electrode 7a and a transmission source electrode 7b
And a drain electrode 8a for reflection and a drain electrode 8b for transmission are formed.

After that, a photosensitive acrylic resin is formed as the interlayer insulating film 18 by a spin coating method to a film thickness of 3 μm. Further, the acrylic resin is subjected to pattern exposure and developed with an alkaline solution. As a result, only the exposed portion is etched by the alkaline solution to form the contact hole 9 penetrating the interlayer insulating film 18. The contact hole 9 is formed to have a good tapered shape.

As described above, by using the photosensitive acrylic resin as the interlayer insulating film 18, the thin film can be formed by the spin coating method. Therefore, a thin film having a thickness of several μm can be easily formed.
Further, the patterning of the interlayer insulating film 18 does not require a photoresist coating step, which is advantageous in terms of productivity.

Further, the acrylic resin in the present embodiment is colored and can be made transparent by exposing the entire surface to light after patterning. The acrylic resin can be made transparent by chemical treatment.

Next, the reflection pixel electrode 2a, the reflection gate wiring 3a and the transmission gate wiring 3b, the source wiring 4, the reflection thin film transistor (TFT) 5a, and the transmission thin film transistor (a) are formed on the interlayer insulating film 18. TF
T) 5b is formed so as to overlap the reflection auxiliary capacitance line 12a. In the present embodiment, when forming the reflective pixel electrode 2a, aluminum (Al) is deposited by a sputtering method and then patterned by a photolithography process. However, the material of the reflective pixel electrode 2a is not limited to aluminum (Al), and other metal materials such as silver (Ag),
Alternatively, an aluminum alloy such as AlSi (Si content of about 1%) may be used as long as it is a film having high reflectance and conductivity.

As described above, the active matrix substrate 1a according to this embodiment can be manufactured.

Further, a liquid crystal cell is manufactured using a conventionally known method such as bonding the alignment coating film and the counter substrate 13, injecting a liquid crystal material, bonding a polarizing plate, and the like.
By installing a backlight on the back surface, a liquid crystal display device using the active matrix substrate 1a is completed.

Further, the active matrix substrate 1 described above
Since a has the reflective pixel electrode 2a provided on the interlayer insulating film 18, unevenness is formed on the surface of the interlayer insulating film 18 by a photolithography process or the like. The electrode 2a can be obtained. Therefore, the unevenness of the surface of the reflective pixel electrode 2a makes it possible to use ambient light with various incident angles, and a brighter liquid crystal display device can be realized.

In the liquid crystal device, the thickness of the liquid crystal layer 29 between the transmissive pixel electrode 2b and the counter electrode 14 is set to be between the reflective pixel electrode 2a and the counter electrode 14. It is desirable to make the thickness larger than the thickness of the liquid crystal layer 29. Thereby, the optical path length of the light reflected by the reflection pixel electrode 2a in the liquid crystal layer 29 and the optical path length of the light passing through the transmission pixel electrode 2b in the liquid crystal layer 29 can be made close to each other. Therefore, it is possible to make uniform the change in light characteristics in both liquid crystal layers 29, and it is possible to improve the light use efficiency.

Further, the thickness of the liquid crystal layer 29 between the transmissive pixel electrode 2b and the counter electrode 14 is set to be equal to that of the liquid crystal layer 29 between the reflective pixel electrode 2a and the counter electrode 14. More preferably, it is twice the thickness. Thereby, the optical path length of the light reflected by the reflection pixel electrode 2a in the liquid crystal layer 29 and the optical path length of the light passing through the transmission pixel electrode 2b in the liquid crystal layer 29 can be made the same. Therefore, it is possible to make the characteristic changes of light in both liquid crystal layers 29 coincide with each other, and it is possible to further improve the light utilization efficiency.

As described above, the active matrix substrate 1a according to the present embodiment has the reflective pixel electrode 2a for reflective display and the transmissive pixel electrode 2b for transmissive display.
And the independent structure, the reflection pixel electrode 2
It is possible to control a and the transmissive pixel electrode 2b by using individual parameters. In the present embodiment, as described above, the reflective pixel electrode 2a and the transmissive pixel electrode 2b are independently controlled as separate pixels, but they are used as one set for displaying an image.

By the way, in the conventional liquid crystal display device, as shown in FIG. 13, a reflective region (reflective pixel electrode) 26 and a transmissive region (transmissive pixel electrode) 28 are formed and reflected in the same pixel. Since the liquid crystal thicknesses of the region and the transmissive region are changed so as to be different, the capacitance Clc of the liquid crystal layer has a different value. In the above liquid crystal display device, due to the structure of the liquid crystal device, the parasitic capacitance Cgd between the gate electrode and the drain electrode, the capacitance of the auxiliary capacitance element (auxiliary capacitance) Ccs,
Further, the gate potential difference ΔVg is the same in each of the regions 26 and 28. Therefore, the respective optimum counter voltages are different, and the difference between the voltage of the counter electrode (not shown) and the optimum counter voltage of the reflective region 26 and / or the difference between the voltage of the counter electrode and the optimum counter voltage of the transmissive region 28. The deviation is one of the causes for lowering the display quality.

On the other hand, in the liquid crystal display device using the active matrix substrate 1a according to the present embodiment, the reflective pixel electrode 2a and the transmissive pixel electrode 2b are controlled by using individual parameters, which will be described later. As described above, the optimum counter voltage of the reflective pixel electrode 2a and the transmissive pixel electrode 2b
Of the counter electrode 14 and the voltage of the counter electrode 14 is set to the voltage value of the optimum counter voltage, whereby the difference between the voltage of the counter electrode 14 and the optimum counter voltage of the reflection pixel electrode 2a, and It is possible to eliminate the deviation between the voltage of the counter electrode 14 and the optimum counter voltage of the transmissive pixel electrode 2b.

Therefore, it is possible to obtain a highly reliable liquid crystal display device having high light utilization efficiency and capable of high-quality display.
Further, it is possible to suppress the flicker phenomenon even when driving at a low frequency in order to suppress power consumption.

A control method using parameters for matching the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b will be described below.

As described above, the voltage applied to each of the pixel electrodes 2a and 2b does not match the source voltage, and shifts from the source voltage at the moment when the gate is closed.

On the other hand, the parameters for controlling the shift of the potential include, for example, the wiring pattern, the structure, and
Various capacitance design parameters such as the parasitic capacitance Cgd between the gate electrode and the drain electrode, the capacitance Clc of the liquid crystal layer 29, the capacitance of the auxiliary capacitance element (hereinafter, referred to as auxiliary capacitance) Ccs, and the gate potential difference due to the material. There are parameters depending on the input signal such as ΔVg.

Therefore, by controlling the various capacitance design parameters individually for the reflective pixel electrode 2a and the transmissive pixel electrode 2b, the optimum counter voltage of the reflective pixel electrode 2a and the optimum of the transmissive pixel electrode 2b are controlled. A first method of matching the counter voltage will be described. Next, for the reflection pixel electrode 2a and the transmission pixel electrode 2b, the optimum counter voltage of the reflection pixel electrode 2a and the optimum counter voltage of the transmission pixel electrode 2b are controlled by individually controlling the parameters according to the input signal. A second method for matching the will be described. Further, the optimum counter voltage of the reflective pixel electrode 2a and the transmissive pixel are controlled by individually controlling the various capacitance design parameters and the parameters based on the input signal for the reflective pixel electrode 2a and the transmissive pixel electrode 2b. A third method of matching the optimum counter voltage of the electrode 2b will be described. Finally, a fourth method will be described in which the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b are matched by controlling the source signal.

First, a first method for individually controlling various capacitance design parameters will be described. In this method, gate signals having the same amplitude are input to the reflective pixel electrode 2a and the transmissive pixel electrode 2b.

Here, the voltage shift amount from the source signal voltage of the reflection pixel electrode potential (hereinafter referred to as the voltage shift amount of the reflection pixel electrode 2a) is ΔVd (r), from the source signal voltage of the transmission pixel electrode potential. Of the voltage shift amount (hereinafter, referred to as the voltage shift amount of the transmissive pixel electrode 2b) of ΔVd (t)
Then, ΔVd (r) and ΔVd (t) are obtained from the above equation (1) by the following equations (2) and (3), respectively.

ΔVd (r) = ΔVg (r) × Cgd (r) / (Cgd (r) + Clc (r) + Ccs (r)) (2) ΔVd (t) = ΔVg (t) × Cgd (t) / (Cgd (t) + Clc (t) + Ccs (t)) (3) The gate potential difference of the reflection pixel electrode 2a is ΔVg.
(R), reflective gate electrode 6a and reflective drain electrode 8
Cgd (r) is the parasitic capacitance between a and the pixel electrode 2 for reflection.
The capacitance of the liquid crystal layer 29 between a and the counter electrode 14 is set to Clc.
(R), the auxiliary capacitance connected to the reflection pixel electrode is Ccs
(R). Further, the gate potential difference of the transmissive pixel electrode 2b is ΔVg (t), the parasitic capacitance between the transmissive gate electrode 6b and the transmissive drain electrode 8b is Cgd (t), the transmissive pixel electrode 2b and the counter electrode 14 are The capacitance of the liquid crystal layer 29 between them is Clc (t), and the auxiliary capacitance connected to the transmissive pixel electrode is Ccs (t). Where each gate potential difference Δ
Vg (r) · ΔVg (t) is the difference between the high level voltage Vgh (r) · Vgh (t) of each gate signal and the low level voltage Vgl (r) · Vgl (t) of each gate signal. .

On the other hand, since the gate signal of the reflective pixel electrode 2a and the gate signal of the transmissive pixel electrode 2b have the same amplitude, the gate potential difference ΔVg of the reflective pixel electrode 2a.
(R) and the gate potential difference ΔVg between the transparent pixel electrode 2b
It has the same value as (t).

Therefore, in order to make the voltage shift amount ΔVd (r) of the reflection pixel electrode 2a and the voltage shift amount ΔVd (t) of the transmission pixel electrode 2b the same, the following expression (4) should be satisfied. The liquid crystal display device may be designed as described above.

Cgd (r) / (Cgd (r) + Clc (r) + Ccs (r)) = Cgd (t) / (Cgd (t) + Clc (t) + Ccs (t)) (4) That is, the above formula Each parasitic capacitance Cgd (r) · Cgd (t) and the capacitance C of each liquid crystal layer 29 so as to satisfy the relationship of (4).
lc (r) · Clc (t) and each auxiliary capacitance Ccs
By selecting (r) · Ccs (t), it is possible to make the voltage shift amount ΔVd (r) of the reflective pixel electrode 2a and the voltage shift amount ΔVd (t) of the transmissive pixel electrode 2b the same. Become.

As described above, it becomes possible to match the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b.

Further, the same gate signal may be input with the reflection gate wiring 3a and the transmission gate wiring 3b as a set. In this case, the frequency of the gate signal can be prevented from becoming twice as high as the frequency of the gate signal of the conventional structure.

That is, in the active matrix substrate 1a of this embodiment, as described above, the pixel electrode 2
Is composed of a reflective pixel electrode 2a made of a metal film and a transmissive pixel electrode 2b made of a transparent conductive film, and individual gate wirings 3a and 3b are provided in each. Therefore, in the active matrix substrate 1a, the phase of the gate signal from the gate wiring connected to the reflective pixel electrode and the gate signal from the gate wiring connected to the transmissive pixel electrode are different from those of the conventional active matrix substrate. It is necessary to input a gate signal having twice the frequency because the phase is different. However, as described above, the reflection gate wiring 3a and the transmission gate wiring 3b are combined as a set,
By inputting the same gate signal, that is, the gate signal having the same amplitude and the same phase, it is not necessary to input the gate signal having the double frequency, and the same frequency as that of the active matrix substrate used in the conventional liquid crystal display device. Display is possible by inputting the gate signal of.

Next, the second method for individually controlling the parameters based on the input signal will be described.

In the active matrix substrate used in the conventional liquid crystal display device, as described above, since the reflective region 26 and the transmissive region 28 have different liquid crystal thicknesses, the capacitance Clc of the liquid crystal layer is different from each other. On the other hand, the gate electrode
The parasitic capacitance Cgd between the drain electrodes, the auxiliary capacitance Ccs, and the gate potential difference ΔVg are the same in each of the regions 26 and 28. Therefore, Cgd / (Cgd + Clc + Cc
The value of s) is different in each area 26 and 28. Therefore, the voltage shift values ΔVd of the respective regions 26 and 28 shown in the above equation (1) are also different values.

Therefore, in the present embodiment, Cgd / between the reflection pixel electrode 2a and the transmission pixel electrode 2b.
Even when the value of (Cgd + Clc + Ccs) is different, the voltage shift amount ΔVd of the reflection pixel electrode 2a.
(R) and the voltage shift amount ΔVd of the transmissive pixel electrode 2b
The gate potential difference ΔVg (r) of the reflective pixel electrode 2a and the gate potential difference ΔVg (t) of the transmissive pixel electrode 2b are individually controlled so that (t) is the same.

That is, the voltage shift amount ΔVd (r) of the reflection pixel electrode 2a and the voltage shift amount ΔVd (t) of the transmission pixel electrode 2b are expressed by the above equations (2) and (3), respectively. Therefore, the liquid crystal display device may be designed so as to satisfy the following expression (5).

ΔVg (r) × Cgd (r) / (Cgd (r) + Clc (r) + Ccs (r)) = ΔVg (t) × Cgd (t) / (Cgd (t) + Clc (t) + Ccs (t) )) (5) As a result, Cgd (r) / of the reflective pixel electrode 2a is
The value of (Cgd (r) + Clc (r) + Ccs (r)) and Cgd (t) / (Cgd of the transmissive pixel electrode 2b).
Even when the values of (t) + Clc (t) + Ccs (t) are different from each other, the gate potential difference ΔVg (r) of the reflective pixel electrode 2a and the gate potential difference ΔVg (t) of the transmissive pixel electrode 2b are different from each other. It is possible to make the voltage shift amount ΔVd (r) of the reflective pixel electrode 2a and the voltage shift amount ΔVd (t) of the transmissive pixel electrode 2b the same by individually controlling the above.

The control using the second method will be specifically described below with reference to FIGS. 5 (a) and 5 (b).

Conventionally, as shown in FIGS. 14A to 14E, the gate potential difference ΔVg of the reflective pixel electrode 26 is set.
(R) and the gate potential difference ΔVg between the transparent pixel electrode 28 and
Even if a gate signal having the same value as (t) is input, the shift amount ΔVd (r) of the reflective pixel electrode 26 and the shift amount ΔVd (t) of the transmissive pixel electrode 28 are different. Therefore, in the present embodiment, for example, as shown in FIG. 5A, the high level voltage Vgh (t) of the gate signal in the transmissive pixel electrode 2b is controlled to, for example, Vgh.
The correction is made to Vgh (t) 'such that (t)> Vgh (t)'.

On the other hand, the drain voltage applied to the transmissive pixel electrode 2b is the gate potential difference Δ according to the above equation (1).
It changes in proportion to Vg (ΔVg = Vgh × Vgl).
Therefore, by correcting the high level voltage Vgh (t) of the gate signal to Vgh (t) ', the shift amount of the drain voltage applied to the transmissive pixel electrode 2b is also ΔVd as shown in FIG. 5B. It changes from (t) to ΔVd (t) '.

Therefore, the transmissive pixel electrode 2b after correction
The voltage shift amount ΔVd (t) ′ of the
In order to make it equal to the shift amount ΔVd (r) of the voltage of a,
The value of the voltage Vgh (t) ′ at the time of inputting the gate signal may be determined. That is, as shown in FIG. 5A, Vgh
If the value of (t) is set to a smaller Vgh (t) 'and the voltage shift amount is reduced by the difference ΔVs between ΔVd (t) and ΔVd (r), the voltage shift amount ΔVd of the reflection pixel electrode 2a is reduced. (R) becomes equal to the corrected shift amount ΔVd (t) ′ of the voltage of the transmissive pixel electrode 2b. However, in FIG.
In FIG. 14D and FIG. 14E, ΔVd is used for convenience.
(T)> ΔVd (r).

As described above, it becomes possible to make the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b coincide with each other.

Next, a third method for individually controlling various capacitance design parameters and parameters by input signals will be described.

Voltage shift amount Δ of the reflection pixel electrode 2a
Vd (r) and voltage shift amount ΔVd of the transmissive pixel electrode 2b
(T) means the above equation (2) and equation (3), respectively.
Indicated by. Therefore, whether or not the gate signals input to the reflective pixel electrode 2a and the transmissive pixel electrode 2b are the same, and the Cg of the reflective pixel electrode 2a is Cg.
d (r) / (Cgd (r) + Clc (r) + Ccs
(R)) value and Cgd (t) / of the transmissive pixel electrode 2b
Whether or not the value of (Cgd (t) + Clc (t) + Ccs (t)) is different from each other, the gate potential difference ΔVg (r of the reflection pixel electrode 2a is set to satisfy the above expression (5). ), The parasitic capacitance Cgd (r) between the reflection gate electrode 6a and the reflection drain electrode 8a, the capacitance Clc (r) of the liquid crystal layer 29 between the reflection pixel electrode 2a and the counter electrode 14, and the reflection pixel. Auxiliary capacitance Ccs (r) connected to the electrode, gate potential difference ΔV of the transmissive pixel electrode 2b
g (t), the parasitic capacitance Cgd (t) between the transparent gate electrode 6b and the transparent drain electrode 8b, and the capacitance Clc of the liquid crystal layer 29 between the transparent pixel electrode 2b and the counter electrode 14.
(T) and the auxiliary capacitance Ccs (t) connected to the transmissive pixel electrode may be selected.

This also makes it possible to make the voltage shift amount ΔVd (r) of the reflection pixel electrode 2a and the voltage shift amount ΔVd (t) of the transmission pixel electrode 2b the same.

As described above, it becomes possible to make the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b coincide with each other.

Next, a fourth method for controlling the source signal will be described.

As described above, the voltage shift amount ΔVd (r) of the reflective pixel electrode 2a and the voltage shift amount ΔVd (t) of the transmissive pixel electrode 2b are expressed by the above equations (2) and (3), respectively. Given in. Therefore, ΔVd (t)
The difference ΔVs between ΔVd (r) and ΔVd (r) is expressed by the following equation (6).

ΔVs = ΔVg (r) × Cgd (r) / (Cgd (r) + Clc (r) + Ccs (r)) − ΔVg (t) × Cgd (t) / (Cgd (t) + Clc (t) + C cs (t)) (6) Therefore, in the present embodiment, for example, FIG.
As shown in, the above ΔVd (t) and ΔVd
The difference ΔVs from (r) is added only to the source signal applied to the transmissive pixel electrode 2b. As a result, as shown in FIG. 6B, the voltage shift amounts are ΔVd (t) and ΔVd.
The difference from (r) is reduced by ΔVs. Therefore, similarly to the second control method, the voltage shift amount ΔVd (r) of the reflection pixel electrode 2a and the corrected voltage shift amount ΔVd (t) ′ of the transmission pixel electrode 2b become equal.

As described above, it becomes possible to match the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b.

Therefore, by using the liquid crystal display layer device having the active matrix substrate 1a,
The optimum counter voltage of the reflective pixel electrode 2a and the transmissive pixel electrode 2
By performing control using a parameter for matching the optimum counter voltage of b, it is possible to obtain a highly reliable liquid crystal display device having high light utilization efficiency and capable of high-quality display.
Further, it is possible to suppress the flicker phenomenon even when driving at a low frequency in order to suppress power consumption.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

[Second Embodiment] The following will describe another embodiment of the present invention in reference to FIGS. 7 and 8. For convenience of explanation, the first embodiment
The members having the same functions as the members shown in the drawing are attached with the same notations and an explanation thereof will be omitted.

As shown in FIG. 7, the active matrix substrate 1b of the present embodiment has a large proportion of the reflective pixel electrode 2a in one pixel. Further, the reflection pixel electrode 2a has an opening P1 having a shape along the outer peripheral portion of the transmission pixel electrode 2b, and the display by the transmission pixel electrode 2b is visually recognized only in the opening P1. be able to.

That is, as shown in FIG. 8, a pair of reflective pixel electrodes 2a is superposed on the peripheral portion of the transmissive pixel electrode 2b via the interlayer insulating film 18.

More specifically, the reflective pixel electrode 2a is used.
Is a peripheral portion of the pair of transparent pixel electrodes 2b, a transparent gate wiring 3b between adjacent source wirings 4, a transparent gate electrode 6b, a transparent source electrode 7b, and a transparent drain electrode 8b. It is overlapped with a part thereof through at least one interlayer insulating film 18.

As described above, the active matrix substrate 1b of the present embodiment can have a higher aperture ratio than the active matrix substrate 1a of the first embodiment. Therefore, it is possible to prevent a decrease in contrast without providing a black matrix for light shielding on the counter substrate 13 side, and it is possible to improve light utilization efficiency.

On the other hand, as shown in the first embodiment, in order to prevent flicker and display with high quality, the optimum counter voltage of the reflection pixel electrode 2a and the optimum counter voltage of the transmission pixel electrode 2b are set. And counter electrode 1
It is desirable that the voltage of 4 is the optimum counter voltage.

Therefore, also in this embodiment, the parameter-based control method shown in the first embodiment is used. That is, the reflective pixel electrode 2a and the transmissive pixel electrode 2b
With respect to and, by using individual parameters to match the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b, and the voltage of the counter electrode 14 to the optimum counter voltage. By setting the voltage value of the counter electrode 14 to the optimum counter voltage of the reflection pixel electrode 2a, and the voltage of the counter electrode 14 and the transmission pixel electrode 2
The deviation from the optimum counter voltage of b is eliminated.

The control method based on the above parameters can be realized by using any one of the four methods shown in the above-mentioned first embodiment, and the description thereof will be omitted.

Therefore, by using the active matrix substrate 1b of the present embodiment, it is possible to obtain a highly reliable liquid crystal display device having high light utilization efficiency and capable of high-quality display. Further, it is possible to suppress the flicker phenomenon even when driving at a low frequency in order to suppress power consumption.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the present invention.

In the above-described embodiment, the reflective pixel electrode 2a includes the transparent gate wiring 3b between the peripheral portion of the pair of transmissive pixel electrodes 2b and the adjacent source wiring 4.
, A transparent gate electrode 6b, and a transparent source electrode 7b
And a part of the transmissive drain electrode 8b with at least one interlayer insulating film 18 interposed therebetween. However, the region overlapped by the pair of reflective pixel electrodes 2a is not particularly limited as described above, and may be any region that can provide a sufficient aperture ratio.

[Third Embodiment] The following will describe another embodiment of the present invention with reference to FIGS. 9 to 11. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment will be designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 9, the active matrix substrate 1c of this embodiment has a large proportion of the reflective pixel electrode 2a in one pixel, as in the second embodiment. Further, the reflective pixel electrode 2a has the opening P2 as in the second embodiment, and the display by the transmissive pixel electrode 2b can be visually recognized only in the opening P2.

That is, as shown in FIG. 10, on the peripheral portion of the transmissive pixel electrode 2b, with the interlayer insulating film 18 interposed,
A pair of reflective pixel electrodes 2a is superposed.

More specifically, the reflective pixel electrode 2a is used.
Is a peripheral portion of the pair of transmissive pixel electrodes 2b, a transmissive gate wiring 3b between adjacent source wirings 4, a transmissive gate electrode 6b, a transmissive source electrode 7b, and a transmissive drain electrode 8b. Overlying at least one interlayer insulating film 18.

Further, the auxiliary capacitance line 20 connected to the pair of the reflective pixel electrode 2a and the transmissive pixel electrode 2b is shared. Furthermore, the common auxiliary capacitance line 20
Are arranged at positions overlapping the reflection pixel electrode 2a.

The transmission gate electrode 3b is arranged between the reflection gate electrode 3a and the auxiliary capacitance wiring 20.

That is, as shown in FIGS. 10 and 11, the active matrix substrate 1c of this embodiment has the following structure.
The portion of the transmissive pixel electrode 2b excluding the range where the display by the transmissive pixel electrode 2b can be visually recognized is disposed between the reflective pixel electrode 2a and the transparent insulating substrate 15, and The common auxiliary capacitance line 20 is arranged between the transparent pixel electrode 2b and the transparent insulating substrate 15.

The transparent pixel electrode 2b has the common auxiliary capacitance line 20 and the gate insulating film 11 interposed therebetween.
A transparent auxiliary capacitance element is formed by and.

With the above structure, the area of the transmissive pixel electrode 2b visible from the counter substrate 13 side does not overlap with the auxiliary capacitance wiring 20, so that the transmissive pixel electrode 2b from the counter substrate 13 side. The area of the visible region can be increased.

Therefore, in the active matrix substrate 1c, the portion of the transmissive pixel electrode 2b excluding the area where the display by the transmissive pixel electrode 2b can be visually recognized is the reflective pixel electrode 2a and the transparent insulating substrate 15. In addition to increasing the aperture ratio, it is possible to further increase the aperture ratio by the arrangement position of the auxiliary capacitance wiring 20.

Therefore, in the active matrix substrate 1c, the aperture ratio can be made higher than that in the second embodiment, and the contrast of the contrast can be improved without providing the black matrix for light shielding on the counter substrate 13 side. It is possible to prevent the decrease, and it is possible to improve the light utilization efficiency.

On the other hand, the above active matrix substrate 1
In c, the reflection auxiliary capacitance element of the reflective pixel electrode 2a does not have the connection electrode 10 shown in the first embodiment but the auxiliary capacitance electrode 19 with the gate insulating film 11 interposed therebetween, as shown in FIG. It is formed by overlapping the common auxiliary capacitance line 20. In addition, the connection electrode 1
When the auxiliary capacitance is formed by using 0, the connection electrode 1
Zeros are overlapped with each other through the transparent gate wiring 3b and the gate insulating film 11, so that a considerably large parasitic capacitance is generated. Therefore, in the active matrix substrate 1c, the auxiliary capacitance electrode 1 is formed through the contact hole 9.
9 is connected to the reflective pixel electrode 2a, and the interlayer insulating film 18 between the reflective pixel electrode 2a and the transparent gate wiring 3b is made of an acrylic resin having a low dielectric constant and a large film thickness. The increase in the parasitic capacitance is suppressed.

On the other hand, as shown in the first embodiment, in order to prevent flicker and display with high quality, the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b are set. And counter electrode 1
It is desirable to set the voltage of 4 to the voltage value of the optimum counter voltage.

Therefore, also in this embodiment, the parameter-based control method shown in the first embodiment is used. That is, the reflective pixel electrode 2a and the transmissive pixel electrode 2b
With respect to and, by using individual parameters to match the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b, and the voltage of the counter electrode 14 to the optimum counter voltage. By setting the voltage value of the counter electrode 14 to the optimum counter voltage of the reflection pixel electrode 2a, and the voltage of the counter electrode 14 and the transmission pixel electrode 2
The deviation from the optimum counter voltage of b is eliminated.

The control method using the above parameters can be realized by using any one of the four methods shown in the above-mentioned first embodiment, and therefore the description thereof will be omitted.

Therefore, by using the active matrix substrate 1c of the present embodiment, it is possible to obtain a highly reliable liquid crystal display device having high light utilization efficiency and capable of high-quality display. Further, it is possible to suppress the flicker phenomenon even when driving at a low frequency in order to suppress power consumption.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the present invention.

For example, the planar shape of the pair of reflective pixel electrodes 2a is set to various shapes within the range in which the auxiliary capacitance wiring 20 is arranged at the position where it is superposed on the reflective pixel electrode 2a as described above. Good.

[Fourth Embodiment] The following will describe another embodiment of the present invention in reference to FIG. For convenience of explanation, members having the same functions as those shown in the drawings of the first or third embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 12, the active matrix substrate 1d of the present embodiment has the reflective gate wiring 3a of the active matrix substrate 1c of the third embodiment.
And the transparent gate wiring 3b as a common gate wiring 3,
Accordingly, the common gate electrode 6 is used as the reflective gate electrode 6a and the transmissive gate electrode 6b of the active matrix substrate 1c.

Therefore, the number of gate wiring lines on the active matrix substrate 1d is only required to be half the number of gate wiring lines on the active matrix substrate 1c in the third embodiment. As a result, in the present embodiment,
In addition to the effect obtained in the third embodiment, it is possible to miniaturize the pixel including one set of the reflective pixel electrode 2a and the transmissive pixel electrode 2b, and a liquid crystal display device with high resolution can be obtained. Further, the yield of the active matrix substrate 1d during production can be reduced, and the production efficiency of the liquid crystal display device including the active matrix substrate 1d can be increased.

On the other hand, as shown in the first embodiment, in order to prevent flicker and display with high quality, the optimum counter voltage of the reflection pixel electrode 2a and the optimum counter voltage of the transmission pixel electrode 2b are set. And counter electrode 1
It is desirable to set the voltage of 4 to the voltage value of the optimum counter voltage.

Therefore, also in this embodiment, the control method based on the parameters shown in the above-mentioned first embodiment is used. That is, the reflective pixel electrode 2a and the transmissive pixel electrode 2b
With respect to and, by using individual parameters to match the optimum counter voltage of the reflective pixel electrode 2a and the optimum counter voltage of the transmissive pixel electrode 2b, and the voltage of the counter electrode 14 to the optimum counter voltage. By setting the voltage value of the counter electrode 14 to the optimum counter voltage of the reflection pixel electrode 2a, and the voltage of the counter electrode 14 and the transmission pixel electrode 2
The deviation from the optimum counter voltage of b is eliminated.

The control method based on the above parameters can be realized by using any one of the four methods shown in the above-mentioned first embodiment, and therefore the description thereof will be omitted.

Therefore, by using the active matrix substrate 1d of the present embodiment, it is possible to obtain a highly reliable liquid crystal display device having high light utilization efficiency and capable of high-quality display. Further, it is possible to suppress the flicker phenomenon even when driving at a low frequency in order to suppress power consumption.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the present invention.

For example, as shown in the third embodiment,
The planar shape of the pair of reflective pixel electrodes 2a may be various shapes within the range in which the auxiliary capacitance line 20 is arranged at the position where it is superposed on the reflective pixel electrode 2a as described above.

[0169]

As described above, in the liquid crystal display device of the present invention, the switching element includes the first switching element and the second switching element, and the reflection pixel electrode is the first switching element. To the first gate line, the transparent pixel electrode is connected to the second gate line via the second switching element, and the auxiliary capacitance element is connected to the reflective pixel electrode. A reflection auxiliary capacitance element and a transmission auxiliary capacitance element connected to the transmission pixel electrode, and the amplitude of the gate signal input to the first gate wiring and the second gate wiring are input. The amplitude of the gate signal, the parasitic capacitance between the gate electrode and the drain electrode of the first switching element, and the parasitic capacitance between the gate electrode and the drain electrode of the second switching element. A capacitance of the liquid crystal layer between the reflection pixel electrode and the counter electrode, a capacitance of the liquid crystal layer between the transmission pixel electrode and the counter electrode, a capacitance of the reflection auxiliary capacitance element, and The capacitance of the transmissive auxiliary capacitance element occurs at the time of switching of the switching element,
The voltage shift amount of the reflection pixel electrode potential from the source signal voltage and the voltage shift amount of the transmission pixel electrode potential from the source signal voltage are set to be the same.

Therefore, in the liquid crystal display device of the present invention, it is possible to suppress the occurrence of display defects such as unevenness and haze which occur when the liquid crystal display device is used for a long period of time. Further, the occurrence of flicker can be suppressed. on the other hand,
Since the reflective pixel electrode and the transmissive pixel electrode are used, the light utilization efficiency is improved. Therefore, there is an effect that it is possible to realize high-quality display with high light utilization efficiency regardless of the state of ambient light.

In the liquid crystal display device of the present invention, the parasitic capacitance between the gate electrode and the drain electrode of the first switching element is Cgd (r),
The capacitance of the liquid crystal layer between the reflective pixel electrode and the counter electrode is set to Cl.
c (r) and the capacitance of the reflection auxiliary capacitance element are C
cs (r), the parasitic capacitance between the gate electrode and the drain electrode of the second switching element is Cgd (t), and the capacitance of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is Clc.
(T), and the capacitance of the transmission auxiliary capacitance element is Cc
s (t), the amplitude of the gate signal input to the first gate wiring is ΔVg (r), and the amplitude of the gate signal input to the second gate wiring is ΔVg (t). ΔVg (r) × Cgd (r) / (Cgd
(R) + Clc (r) + Ccs (r)) = ΔVg (t)
× Cgd (t) / (Cgd (t) + Clc (t) + Cc
It satisfies the relationship of s (t).

Therefore, in the above liquid crystal display device, there is an effect that the optimum reflection opposing voltage and the optimum transmission opposing voltage can be matched.

Further, the liquid crystal display device of the present invention is the same as the above liquid crystal display device, in which the same gate signal is input to the first gate wiring and the second gate wiring.

Therefore, it is not necessary to shift the phase of the gate signal from the gate wiring connected to the reflection pixel electrode and the phase of the gate signal from the gate wiring connected to the transmission pixel electrode. It is possible to halve the frequency of the gate signal as compared with the case where the gate signals are sequentially input with the shift. Therefore, it is possible to achieve high-quality display while reducing power consumption.

The liquid crystal display device of the present invention is, as described above,
The switching element includes a first switching element and a second switching element, the reflection pixel electrode is connected to a first gate line via the first switching element, and the transmission pixel electrode is , A second auxiliary wiring connected to the second gate wiring through a second switching element, the auxiliary capacitance element being connected to the reflection pixel electrode, and the reflection auxiliary capacitance element being connected to the transmission pixel electrode. And an auxiliary capacitance element for use in the transmission, and a voltage shift amount from the source signal voltage of the pixel electrode potential for reflection and the source of the pixel electrode potential for transmission, which occur when the first switching element and the second switching element are switched. In accordance with the display timing of each of the reflective pixel electrode and the transmissive pixel electrode so that the voltage shift amount from the signal voltage becomes the same. The source signal voltages applied to the first pixel electrode for reflecting through the switching element, is intended to be made different from the source signal voltages applied to the transmissive pixel electrode through the second switching element.

Therefore, in the liquid crystal display device of the present invention, it is possible to suppress the occurrence of display defects such as unevenness and blurring that occur when the liquid crystal display device is used for a long period of time. Further, the occurrence of flicker can be suppressed. on the other hand,
Since the reflective pixel electrode and the transmissive pixel electrode are used, the light utilization efficiency is improved. Therefore, there is an effect that it is possible to realize high-quality display with high light utilization efficiency regardless of the state of ambient light.

In the liquid crystal display device of the present invention, the parasitic capacitance between the gate electrode and the drain electrode of the first switching element is Cgd (r),
The capacitance of the liquid crystal layer between the reflective pixel electrode and the counter electrode is set to Cl.
c (r) and the capacitance of the reflection auxiliary capacitance element are C
cs (r), the parasitic capacitance between the gate electrode and the drain electrode of the second switching element is Cgd (t), and the capacitance of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is Clc.
(T), and the capacitance of the transmission auxiliary capacitance element is Cc
s (t), the amplitude of the gate signal input to the first gate wiring is ΔVg (r), and the amplitude of the gate signal input to the second gate wiring is ΔVg (t). Further, the difference ΔVs between the source signal voltage applied to the reflection pixel electrode and the source signal voltage applied to the transmission pixel electrode is ΔVs = ΔVg (r) × Cgd
(R) / (Cgd (r) + Clc (r) + Ccs
(R)) − ΔVg (t) × Cgd (t) / (Cgd
It satisfies the relation of (t) + Clc (t) + Ccs (t)).

Therefore, the potential after the shift of the reflective pixel electrode and the potential after the shift of the transmissive pixel electrode coincide with each other due to the difference ΔVs of the source signal voltage.
Therefore, in the liquid crystal display device, it is possible to match the optimum reflection opposing voltage and the optimum transmission opposing voltage.

Further, in the liquid crystal display device of the present invention, in the above liquid crystal display device, the thickness of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is set to the liquid crystal layer between the reflective pixel electrode and the counter electrode. It is made larger than the layer thickness.

Therefore, changes in the light characteristics of the liquid crystal layer corresponding to the area of the reflective pixel electrode and the liquid crystal layer corresponding to the area of the transmissive pixel electrode can be made uniform. Therefore, there is an effect that it is possible to further increase the light utilization efficiency.

Further, in the liquid crystal display device of the present invention, in the above liquid crystal display device, the thickness of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is set to the liquid crystal layer between the reflective pixel electrode and the counter electrode. It is twice the thickness of the layer.

Therefore, it is possible to make the changes in the light characteristics of the liquid crystal layer corresponding to the region of the reflective pixel electrode and the liquid crystal layer corresponding to the region of the transmissive pixel electrode coincide with each other. Therefore, there is an effect that it is possible to further increase the light use efficiency.

Further, in the liquid crystal display device of the present invention, in the above liquid crystal display device, a peripheral portion of the transmissive pixel electrode is superposed by a pair of reflective pixel electrodes via one or more insulating films. It is a thing.

Therefore, the aperture ratio of the entire liquid crystal display device is increased, and the light utilization efficiency can be improved.

Further, in the liquid crystal display device of the present invention, in the above liquid crystal display device, the reflection auxiliary capacitance element is formed by the reflection auxiliary capacitance wiring and the conductive film electrically connected to the reflection pixel electrode. The transparent auxiliary capacitance element is formed by a transparent auxiliary capacitance line and a transparent pixel electrode, and the reflection auxiliary capacitance line and the transparent auxiliary capacitance line are
The reflective pixel electrode and the transmissive pixel electrode forming a pair have the same wiring, and the auxiliary capacitance wiring does not overlap the area of the transmissive pixel electrode where the reflective pixel electrode does not overlap.

Therefore, it is possible to further increase the actual area used for the liquid crystal display of the transmissive pixel electrode by the area of the auxiliary capacitance wiring. Therefore, the aperture ratio of the entire liquid crystal display device can be further increased, and the light utilization efficiency can be further enhanced.

Further, in the liquid crystal display device of the present invention, in the above liquid crystal display device, the first gate wiring and the second gate wiring are the same wiring in the pair of the reflective pixel electrode and the transmissive pixel electrode. Is what is.

Therefore, the pixels can be miniaturized, a liquid crystal display device having a high resolution can be obtained, and at the same time, the yield in the production of the liquid crystal display device can be significantly reduced. .

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of an active matrix substrate according to the present invention.

FIG. 2 A of the active matrix substrate when the active matrix substrate is used in a liquid crystal display device.
It is a sectional view taken along line A-A.

FIG. 3B of the active matrix substrate when the active matrix substrate is used in a liquid crystal display device.
FIG. 6 is a cross-sectional view taken along line B-arrow.

FIG. 4 is a C of the active matrix substrate when the active matrix substrate is used in a liquid crystal display device.
It is a C line arrow cross section.

FIG. 5A is a thin film transistor (T) connected to a transmissive pixel electrode in the active matrix substrate.
FIG. 4B is a waveform diagram showing a corrected gate signal input to the gate electrode of FT), and FIG. 6B is a waveform diagram of a signal showing a corrected drain voltage applied to the transmissive pixel electrode on the active matrix substrate. is there.

FIG. 6A is a waveform diagram of a corrected source signal input to a source electrode in the active matrix substrate, and FIG. 6B is a waveform diagram of a corrected source signal applied to a transmissive pixel electrode in the active matrix substrate. It is a wave form diagram of the signal which shows drain voltage.

FIG. 7 is a plan view showing another embodiment of the active matrix substrate of the present invention.

FIG. 8 is a view showing the D of the active matrix substrate when the active matrix substrate is used in a liquid crystal display device.
FIG. 6 is a cross-sectional view taken along the line D-arrow.

FIG. 9 is a plan view showing still another embodiment of the active matrix substrate of the present invention.

FIG. 10 is a cross-sectional view taken along line EE of the active matrix substrate when the active matrix substrate is used in a liquid crystal display device.

FIG. 11 is a cross-sectional view taken along the line FF of the active matrix substrate when the active matrix substrate is used in a liquid crystal display device.

FIG. 12 is a plan view showing still another embodiment of the active matrix substrate according to the present invention.

FIG. 13 is a plan view showing a conventional active matrix substrate.

14A is a waveform diagram showing a gate signal input to a gate electrode of a thin film transistor (TFT) connected to a reflective pixel electrode in the conventional active matrix substrate, and FIG. It is a wave form diagram of the gate signal input into the gate electrode of the thin film transistor (TFT) connected to the pixel electrode for transmission in an active matrix substrate, (c) is a source signal input into the source electrode in the said conventional active matrix substrate. FIG. 4D is a waveform diagram of a signal indicating a drain voltage applied to the reflective pixel electrode in the conventional active matrix substrate, and FIG. 6E is a waveform diagram for transmission in the conventional active matrix substrate. It is a wave form diagram of the signal which shows the drain voltage applied to a pixel electrode.

[Explanation of symbols]

1a, 1b, 1c, 1d Active matrix substrate 2 Pixel electrode 2a Reflective pixel electrode 2b Transmissive pixel electrode 3 Gate wiring 3a Reflective gate wiring (first gate wiring) 3b Transparent gate wiring (second gate wiring) 4 source wiring 5 thin film transistor (switching element) 5a reflective thin film transistor (first switching element) 5b transmissive thin film transistor (second switching element) 6 gate electrode 6a reflective gate electrode 6b transmissive gate electrode 7 source electrode 7a reflective Source electrode 7b Transmission source electrode 8 Drain electrode 8a Reflection drain electrode 8b Transmission drain electrode 9 Contact hole 10 Connection electrode 11 Gate insulating film 12 Auxiliary capacitance wiring 12a Reflection auxiliary capacitance wiring 12b Transmission auxiliary capacitance wiring 13 Counter substrate 14 Counter electrode 15 transparent Substrate 16 semiconductor layer 17 doped semiconductor layer 18 interlayer insulating film (insulating film) 19 auxiliary capacitance electrode (conductive film) 20 auxiliary capacitance wiring 21 gate wiring 22 source wiring 23 thin film transistor (TFT) 24 contact hole 25 connection wiring 26 reflection Area / reflection pixel electrode 27 Auxiliary capacitance wiring 28 Transmission area / transmission pixel electrode 29 Liquid crystal layers P1 and P2 Opening

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 624 G09G 3/20 624B 3/36 3/36 H01L 21/336 H01L 29/78 612Z 29 / 786 F term (reference) 2H092 GA13 JA24 JB04 JB05 JB42 JB69 NA07 NA29 PA06 2H093 NA16 NC03 NC34 NC35 NC65 ND09 ND10 ND12 ND35 ND47 NH05 5C006 AC24 AF46 BB16 BB28 BC06 BC11 FA06 DD06BB06A11 AA30 BB01 CC07 DD02 EE44 GG45 HK02 HK07 HK08 HK22 HK33 HK35 HL01 HL02 HL03 HL06 NN02 NN27 NN36 NN73

Claims (10)

[Claims] 1. A plurality of pixel electrodes arranged in a matrix having a reflective pixel electrode for performing reflective display and a transmissive pixel electrode for performing transmissive display, and an auxiliary for holding the potential of the pixel electrode. A switching element that includes a capacitor, a source wiring that supplies a source signal, a gate wiring that supplies a gate signal, a source electrode, a gate electrode, and a drain electrode, and that selects the source signal to supply the source signal to the pixel electrode. An active matrix substrate having an element, a counter substrate having a counter electrode facing the reflective pixel electrode and the transmissive pixel electrode, and a liquid crystal layer formed between the active matrix substrate and the counter substrate. In the liquid crystal display device including: the switching element includes a first switching element and a second switching element. The reflection pixel electrode is connected to the first gate line via the first switching element, and the transmission pixel electrode is connected to the second gate line via the second switching element. The auxiliary capacitance element has a reflection auxiliary capacitance element connected to the reflection pixel electrode and a transmission auxiliary capacitance element connected to the transmission pixel electrode, and is input to the first gate line. Amplitude of the gate signal input to the second gate wiring, the parasitic capacitance between the gate electrode and the drain electrode of the first switching element, and the gate of the second switching element. A parasitic capacitance between an electrode and a drain electrode, a capacitance of the liquid crystal layer between the reflection pixel electrode and the counter electrode,
The capacitance of the liquid crystal layer between the transmissive pixel electrode and the counter electrode, the capacitance of the reflective auxiliary capacitance element, and the capacitance of the transmissive auxiliary capacitance element are generated at the time of switching of the switching element. A liquid crystal display device, wherein the amount of voltage shift of the pixel electrode potential for use from the source signal voltage and the amount of voltage shift of the pixel electrode potential for transmission from the source signal voltage are set to be the same. 2. The parasitic capacitance between the gate electrode and the drain electrode of the first switching element is Cgd (r), and the capacitance of the liquid crystal layer between the reflective pixel electrode and the counter electrode is Clc.
(R) and the capacitance of the reflection auxiliary capacitance element are Cc
s (r), the parasitic capacitance between the gate electrode and the drain electrode of the second switching element is Cgd (t), the capacitance of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is Clc (t), And the capacitance of the transmissive auxiliary capacitance element is Ccs (t), the amplitude of the gate signal input to the first gate wiring is ΔVg (r), and the gate input to the second gate wiring is When the signal amplitude is ΔVg (t), ΔVg (r) × Cgd (r) / (Cgd (r) + Clc
(R) + Ccs (r)) = ΔVg (t) × Cgd (t)
The liquid crystal display device according to claim 1, wherein a relationship of / (Cgd (t) + Clc (t) + Ccs (t)) is satisfied. 3. The liquid crystal display device according to claim 1, wherein the same gate signal is input to the first gate wiring and the second gate wiring. 4. A plurality of pixel electrodes arranged in a matrix having a reflective pixel electrode for performing a reflective display and a transmissive pixel electrode for performing a transmissive display, and an auxiliary for holding the potential of the pixel electrode. A switching element that includes a capacitor, a source wiring that supplies a source signal, a gate wiring that supplies a gate signal, a source electrode, a gate electrode, and a drain electrode, and that selects the source signal to supply the source signal to the pixel electrode. An active matrix substrate having an element, a counter substrate having a counter electrode facing the reflective pixel electrode and the transmissive pixel electrode, and a liquid crystal layer formed between the active matrix substrate and the counter substrate. In the liquid crystal display device including: the switching element includes a first switching element and a second switching element. The reflection pixel electrode is connected to the first gate line via the first switching element, and the transmission pixel electrode is connected to the second gate line via the second switching element. The auxiliary capacitance element has a reflection auxiliary capacitance element connected to the reflection pixel electrode and a transmission auxiliary capacitance element connected to the transmission pixel electrode, and the first switching element and the The reflection is performed so that the voltage shift amount of the reflection pixel electrode potential from the source signal voltage and the voltage shift amount of the transmission pixel electrode potential from the source signal voltage generated at the time of switching of the second switching element are the same. The first pixel in accordance with the respective display timings of the pixel electrode for display and the pixel electrode for transmission.
And a source signal voltage applied to the reflective pixel electrode via the second switching element and a source signal voltage applied to the transmissive pixel electrode via the second switching element. Display device. 5. The parasitic capacitance between the gate electrode and the drain electrode of the first switching element is Cgd (r), and the capacitance of the liquid crystal layer between the reflective pixel electrode and the counter electrode is Clc.
(R) and the capacitance of the reflection auxiliary capacitance element are Cc
s (r), the parasitic capacitance between the gate electrode and the drain electrode of the second switching element is Cgd (t), the capacitance of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is Clc (t), And the capacitance of the transmissive auxiliary capacitance element is Ccs (t), the amplitude of the gate signal input to the first gate wiring is ΔVg (r), and the gate input to the second gate wiring is When the signal amplitude is ΔVg (t), the difference Δ between the source signal voltage applied to the reflective pixel electrode and the source signal voltage applied to the transmissive pixel electrode is Δ.
Vs is ΔVs = ΔVg (r) × Cgd (r) / (Cgd (r)
+ Clc (r) + Ccs (r)) − ΔVg (t) × Cg
d (t) / (Cgd (t) + Clc (t) + Ccs
The liquid crystal display device according to claim 4, wherein the relationship (t) is satisfied. 6. The thickness of the liquid crystal layer between the transmissive pixel electrode and the counter electrode is greater than the thickness of the liquid crystal layer between the reflective pixel electrode and the counter electrode. 6. The liquid crystal display device according to any one of items 5 to 5. 7. The liquid crystal layer between the transmissive pixel electrode and the counter electrode is twice as thick as the liquid crystal layer between the reflective pixel electrode and the counter electrode. Item 7. A liquid crystal display device according to item 6. 8. A peripheral portion of the transmissive pixel electrode is superposed by a pair of reflective pixel electrodes with one or more insulating films interposed therebetween. The liquid crystal display device according to item 1. 9. The reflection auxiliary capacitance element is formed of a reflection auxiliary capacitance wiring and a conductive film electrically connected to the reflection pixel electrode, and the transmission auxiliary capacitance element is formed of a transmission auxiliary capacitance wiring. Formed by a transmissive pixel electrode, the reflective auxiliary capacitance line and the transmissive auxiliary capacitance line are the same line in the reflective pixel electrode and the transmissive pixel electrode forming a pair,
9. The liquid crystal display device according to claim 1, wherein the auxiliary capacitance line does not overlap a region of the transmissive pixel electrode where the reflective pixel electrode does not overlap. 10. The liquid crystal display device according to claim 9, wherein the first gate wiring and the second gate wiring are the same wiring in the pair of the reflective pixel electrode and the transmissive pixel electrode. .