JP2006201267A - Liquid crystal display device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain stable display characteristics by improving light resistance and orientation of an alignment film in a liquid crystal display device and a projector.
A pair of substrates each including a first substrate and a second substrate, a pair of alignment films disposed on the pair of substrates, and a liquid crystal layer sandwiched between the pair of alignment films. A liquid crystal display panel having the pair of alignment films made of a material mainly composed of all aliphatic polyimide or aliphatic polyimide, and the first substrate of the pair of substrates is displayed on the liquid crystal display panel. In the state of being arranged on the surface side, the crossing angle in the clockwise direction from the rubbing direction of the alignment film on the first substrate of the one liquid crystal display panel to the rubbing direction of the alignment film on the second substrate is The angle is smaller than 90 °.
[Selection] Figure 6

Description

  The present invention relates to a liquid crystal display device and a projector, and more particularly to a liquid crystal display device and a projector using a reflective liquid crystal display panel.

In a liquid crystal display device for projector use, intense light about 10,000 times as large as that of a direct-view TFT product is incident.
In projectors using RGB three-plate liquid crystal display devices, in particular, blue liquid crystal display devices irradiated with light on the short wavelength side where light absorption of organic materials is large are likely to cause alignment film degradation and liquid crystal degradation due to light. If the display is for a long time, the display quality will be impaired.
Therefore, it is known to suppress the deterioration of the alignment film in the blue liquid crystal display device. (See Patent Document 1 below)
In Patent Document 1, an alignment film made of an aliphatic polyamide and an aromatic polyimide having an absorbance at a wavelength of 380 to 500 nm of 0.03 or less is provided on a liquid crystal display panel of a blue liquid crystal display device in order to suppress alignment film deterioration. The light resistance is improved by using an aliphatic polyamide having a low absorbance, and in order to secure the orientation with the aromatic polyimide, a laminated structure is formed in which the aromatic polyimide is thinly formed on the surface of the aliphatic polyamide.
In an active matrix liquid crystal display device, the active elements are turned on and supplied from the video lines by supplying a scanning voltage for turning on the active elements for one horizontal scanning time to the sequential scanning lines. The video voltage is supplied to the pixel electrode through the active element, the pixel capacitance between the pixel electrode and the counter electrode is charged to a predetermined voltage, and the alignment direction of the liquid crystal molecules of the pixel is changed based on this charging voltage. Display an image.
When the power of the active matrix liquid crystal display device is turned off, the signal voltage applied to each electrode disappears and the active element is also turned off.

As prior art documents related to the invention of the present application, there are the following.
JP-A-2001-42334 (Liquid Crystal Device and Projection Display Device)

However, since strong light is incident on the liquid crystal display device for projector use, in the blue liquid crystal display device described in Patent Document 1, the aromatic thinly formed on the surface of the aliphatic polyamide with the passage of time. There was a problem that polyimide deteriorates, orientation deteriorates and display characteristics are impaired.
Further, when the power of the active matrix liquid crystal display device is turned off, the signal voltage applied to each electrode disappears and the active element is also turned off. Therefore, the electric charge accumulated in the pixel capacitor is held for a long time because the discharge path is interrupted.
This charge gradually decreases due to self-discharge. However, if the charge is retained in the liquid crystal capacitor for a long time, an afterimage remains on the liquid crystal display panel, and the display quality is significantly deteriorated, and the charge is retained in the liquid crystal capacitor for a long time. Since this state is equivalent to a state in which a DC voltage is applied to the liquid crystal, in the worst case, the inclination of the liquid crystal molecules is fixed and the life of the liquid crystal is shortened.
In order to solve the above-described problems, in an active matrix liquid crystal display device, when the liquid crystal display device is turned off, the order and time for turning off the power are strictly controlled by an external drive circuit. Yes.
However, there is a problem that when the liquid crystal display device is turned off, it is difficult to strictly control the order and time of turning off the power from the external driving circuit.
The present invention has been made in order to solve the above-described problems of the prior art, and an object of the present invention is to improve the light resistance and orientation of the alignment film in a liquid crystal display device and a projector, thereby improving stability. It is an object of the present invention to provide a technique capable of obtaining the display characteristics.
Another object of the present invention is to provide a technique capable of quickly discharging charges accumulated in a pixel capacitor when the power is turned off in a liquid crystal display device and a projector. .
The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
In order to solve the above-described problems, in the present invention, an alignment film mainly composed of an aliphatic polyimide or an aliphatic polyimide is formed on both upper and lower substrates constituting a liquid crystal display panel of a blue liquid crystal display device of a liquid crystal projector. Then, the upper and lower substrates are rubbed in the direction of widening the twist angle of 1 ° to 10 ° with respect to the red and green liquid crystal display panels on which the alignment film mainly composed of aromatic polyimide is formed. .
Further, according to the present invention, when the power of the liquid crystal display device is turned off, the reset signal is validated, the selection voltage is applied to all the scanning lines, the active elements of all the pixels are turned on, and a plurality of images are displayed. Apply a voltage of VCOM to the line.

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
According to the liquid crystal display device and the projector of the present invention, it is possible to improve the light resistance and orientation of the alignment film, and to obtain stable display characteristics.
According to the liquid crystal display device and the projector of the present invention, when the power is turned off, the charge accumulated in the liquid crystal capacitor can be discharged quickly.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In all the drawings for explaining the embodiments, parts having the same functions are given the same reference numerals, and repeated explanation thereof is omitted.
FIG. 1 is a block diagram showing a projector that uses three RGB reflective liquid crystal display devices according to an embodiment of the present invention.
As shown in the figure, the white light emitted from the lamp 10 is removed from the ultraviolet light and infrared light by the IR filter 11 and the UV filter 12, and becomes visible light necessary for display.
Visible light that has passed through the UV filter 12 is color-separated into R, G, and B by a dichroic mirror 13, and each polarizing plate (14R, 14G, 14B), polarizing beam splitter (15R, 15G, 15B), and phase plate Passes (16R, 16G, 16B) and enters the reflective liquid crystal display device (17R, 17G, 17B).
For example, in the case of white display of a normally white liquid crystal display device, linearly polarized light incident on the reflective liquid crystal display device (17R, 17G, 17B) passes through the liquid crystal layer of the liquid crystal display panel. Becomes circularly polarized light, and passes through the liquid crystal layer again at the time of reflection, and becomes linearly polarized light whose incident polarization angle and phase are rotated by 90 °.
The linearly polarized light emitted from the reflective liquid crystal display device (17R, 17G, 17B) passes through the polarizing beam splitter (15R, 15G, 15B) and the half mirror 18, and is color-combined. Projected on the projection screen 20. As a result, an enlarged image is displayed on the projection screen 20.

Next, the structure of the reflective liquid crystal display device of this embodiment will be described with reference to FIG.
In FIG. 2, 100 is a liquid crystal display panel, 1 is a drive circuit substrate as a second substrate, 2 is a transparent substrate (for example, a glass substrate) as a first substrate, 3 is a liquid crystal composition, and 4 is a spacer. . The spacer 4 forms a cell gap d that is a constant interval between the driving circuit substrate 1 and the transparent substrate 2. The liquid crystal composition 3 is sandwiched between the cell gaps d.
Reference numeral 5 denotes a reflective electrode (pixel electrode) formed on the drive circuit substrate 1. A counter electrode 6 applies a voltage to the liquid crystal composition 3 between the reflective electrode 5 and the counter electrode 6. 7 and 8 are alignment films which align liquid crystal molecules in a certain direction.
Reference numeral 30 denotes an active element that supplies a gradation voltage to the reflective electrode 5. Reference numeral 34 denotes a source region of the active element 30, 35 denotes a drain region, and 36 denotes a gate electrode.
Reference numeral 38 denotes an insulating film, 31 denotes a first electrode that forms a pixel capacitor, and 40 denotes a second electrode that forms a pixel capacitor. The first electrode 31 and the second electrode 40 form a capacitance via the insulating film 38.
Reference numeral 41 denotes a first interlayer film, and 42 denotes a first conductive film. The first conductive film 42 electrically connects the drain region 35 to the second electrode 40. 43 is a second interlayer film, 44 is a first light shielding film, 45 is a third interlayer film, and 46 is a second light shielding film. A through hole 42CH is formed in the second interlayer film 43 and the third interlayer film 45, and the first conductive film 42 and the second light shielding film 46 are electrically connected. 47 is a fourth interlayer film, 48 is a second conductive film forming the reflective electrode 5, and 49 is a conductive layer. The grayscale voltage is transmitted from the drain region 35 of the active element 30 to the reflective electrode 5 through the first conductive film 42, the through hole 42 CH, and the second light shielding film 46.

The liquid crystal display device of this embodiment is of a reflective type, and a large amount of light is applied to the liquid crystal display panel 100. The light shielding film shields light from entering the semiconductor layer of the drive circuit board. In the reflective liquid crystal display device, the light irradiated to the liquid crystal display panel 100 is incident from the transparent substrate 2 side (upper side in FIG. 2), passes through the liquid crystal composition 3, is reflected by the reflective electrode 5, and is again reflected by the liquid crystal composition 3. Then, the light passes through the transparent substrate 2 and is emitted from the liquid crystal display panel 100.
However, part of the light applied to the liquid crystal display panel 100 leaks from the gap between the reflective electrodes 5 to the drive circuit board side. The first light shielding film 44 and the second light shielding film 46 are provided so that light does not enter the active element 30.
In the present embodiment, the light shielding film is formed of a conductive layer, the second light shielding film 46 is electrically connected to the reflective electrode 5, and a pixel potential control signal is supplied to the first light shielding film 44. The light shielding film also functions as part of the pixel capacitance.
In this embodiment, an opaque silicon substrate is used as the drive circuit substrate 1. Accordingly, there is an advantage that the active element 30 and the wiring can be provided under the reflective electrode 5 and the reflective electrode 5 serving as a pixel can be widened to realize a so-called high aperture ratio. In addition, there is an advantage that heat generated by the light applied to the liquid crystal display panel 100 can be radiated from the back surface of the drive circuit board 1.

In this embodiment, among the three liquid crystal display panels of R, G, and B, an alignment film containing all aliphatic polyimide or aliphatic polyimide as a main component on both the upper and lower substrates of the blue liquid crystal display panel. 7 and 8), and in the rubbing process, the phase shift is corrected by offsetting the rubbing angles of the upper and lower substrates.
Note that alignment films (7, 8) mainly composed of aromatic polyimide are formed on both the upper and lower substrates of the red and green liquid crystal display panels.
As described above, a liquid crystal display device for a projector uses about 10,000 times stronger light than a direct-view TFT product. Therefore, when considering the light resistance of the panel, it is necessary to consider not only the leakage light of the UV filter mounted on the projector but also visible light having a wavelength of 400 nm or more.
In projectors using a three-panel liquid crystal display panel of R, G, and B, particularly, blue panels irradiated with light on the short wavelength side where light absorption of organic materials is large cause deterioration of alignment film and liquid crystal due to light. It is easy, and the display quality is impaired in the display for a long time.
In general, the absorbance of organic substances gradually increases as the wavelength becomes shorter, and the absorbance rapidly increases from a certain wavelength or less, that is, from a so-called absorption edge.
Similarly, there is a correlation between the absorbance in the visible light band of the alignment film and the wavelength of the absorption edge, and as shown in FIG. 3, the blue panel of the projector is irradiated by improving the wavelength of the absorption edge to the lower wavelength side. Absorbance in the 400-500 nm band can also be reduced.
As described above, in this embodiment, the alignment film (7, 8) mainly composed of the aliphatic polyimide or the aliphatic polyimide having the absorption edge wavelength of 250 nm or less is formed on the blue liquid crystal display panel. As a result, it is possible to suppress deterioration of light resistance in the 400 to 500 nm band and maintain stable display quality over a long period of operation. Thereby, a liquid crystal projector excellent in light resistance can be configured.

However, the alignment film (7, 8) mainly composed of all aliphatic polyimide or aliphatic polyimide is excellent in light resistance, but has poor alignment property, in particular, alignment regulating force, as shown in FIG. The effective twist angle (twist in FIG. 5) tends to be smaller than the twist angle controlled by the rubbing direction of the upper and lower substrates.
In particular, when the chiral pitch of the liquid crystal composition 3 is constant, the effective twist angle becomes narrower due to the tension between the liquid crystal molecules in the direction in which the twist angle of the upper and lower substrates becomes narrower as the gap of the liquid crystal cell is narrower.
In such a case, the outgoing polarization angle does not become 90 ° with respect to the incident polarization angle, resulting in a deterioration in display characteristics, particularly contrast.
In order to improve such a problem, in this embodiment, as shown in FIG. 6, when the rubbing process of the alignment films (7, 8) formed on the upper and lower substrates is performed, a target offset angle (of FIG. By applying the offset), the effective twist angle (twist in FIG. 4) can be brought into an ideal state as shown in FIG.
As a result, the phase of the incident polarization angle and the output polarization angle becomes 90 °, and the light resistance can be improved without impairing the contrast.
4 to 6, a dotted line (A) with an arrow indicates the rubbing direction of the alignment film 8 formed on the transparent substrate (glass substrate) 2, and a solid line (B) with an arrow indicates a drive circuit board ( The rubbing direction of the alignment film 7 formed on the (silicon substrate) 1 is shown.
In this embodiment, the twist in FIG. 6 is 90 °, and the offset in FIG. 6 is 5 °. Therefore, in the blue liquid crystal display panel of the present embodiment, the rubbing direction of the alignment film 8 of the transparent substrate 2 in a state where the transparent substrate 2 is disposed on the display surface side (polarization beam splitter side in FIG. 1) of the liquid crystal display panel. Therefore, the angle of the crossing angle in the clockwise direction to the rubbing direction of the alignment film 7 of the drive circuit substrate 1 is smaller than 90 ° (80 ° in this embodiment).
In the liquid crystal display panel for red and green, the alignment film 7 of the driving circuit substrate 1) from the alignment film 8 rubbing direction of the transparent substrate 2 in a state where the transparent substrate 2 is disposed on the display surface side of the liquid crystal display panel. The angle of the crossing angle in the clockwise direction to the rubbing direction is 90 °.

In this embodiment, a phase plate (16R, 16G, 16B) for correcting the phase of incident polarized light such as a λ / 4 plate is provided on the polarizing beam splitter side of the reflective liquid crystal display device (17R, 17G, 17B). Be placed.
This phase plate (16R, 16G, 16B) can be adjusted, and when the effective twist angle cannot be corrected by the rubbing angle offset, it is possible to provide redundancy for phase shift correction. is there.
FIG. 7 shows the relationship between the control twist angle and the contrast when the rubbing angle is offset during the rubbing process, with and without a phase correction plate.
By setting the control twist angle to 90 ° or more by offsetting the rubbing angle, a high contrast value can be obtained.
In addition, a change in the twist angle due to variations in the rubbing angle or the like significantly reduces the contrast value. However, by arranging the phase plates (16R, 16G, and 16B) in the front stage of the panel, redundancy with respect to a decrease in contrast is achieved. Is obtained.
As a result, it is possible to realize a liquid crystal projector that maintains stable image quality and has high contrast.

FIG. 8 is a circuit diagram showing a driving circuit of the liquid crystal display device according to the embodiment of the present invention.
In the liquid crystal display device of this embodiment, the vertical scanning circuit 130 sequentially outputs a selection signal for one horizontal scanning time with respect to the gate line (G; also referred to as scanning line).
Accordingly, the active element (thin film transistor) 30 is turned on for each horizontal scanning line for one horizontal scanning time.
Further, the horizontal scanning circuit 120 sequentially outputs a timing signal for selecting a drain line (D; also referred to as a video line) during one horizontal scanning time.
As a result, the video voltage from the video lines (Video 1 to Video 8) is applied to the pixel electrode 5 through the active element (TFT), and the liquid crystal capacitance (Clc) between the pixel electrode 5 and the counter electrode 6 is a predetermined voltage. Is charged.
Based on this charging voltage, an image is displayed by changing the alignment direction of the liquid crystal molecules of the pixel.
The built-in AC scanning circuit 135 is used to control a voltage applied to one end of the pixel capacitor (Cst) and apply a negative (or positive) voltage to the pixel electrode 5.
Further, the p-type MOS transistor (PMg) of the gate-off auxiliary circuit 135 is turned on when both control signals (CNT1, CNT2) are at the low level (hereinafter referred to as L level), and the high potential of VBB is applied to the gate line G. To do.

In this embodiment, a NAND circuit (NANDa) is connected to the output of the horizontal scanning circuit 120, and a reset signal (RST) is input to the NAND circuit (NANDa). The output of the NAND circuit (NANDa) is input to the level shift circuit (LS1) via an inverter.
A NAND circuit (NANDb) is connected to the output of the vertical scanning circuit 130, and a reset signal (RST) is input to the NAND circuit (NANDb). The output of the NAND (NANDb) is input to the level shift circuit (LS2) via the inverter.
Further, a p-type MOS transistor (PMd) is connected to the other end of the drain line (D), and a voltage of VCOM (voltage applied to the counter electrode 6) is applied to the source side.
A NAND circuit (NANDc) is connected to the output of the built-in AC scanning circuit 150, and a reset signal (RST) is input to the NAND circuit (NANDc). The output of the NAND circuit (NANDc) is input to the level shift circuit (LS3).
The reset signal (RST) is set to Low (hereinafter, L level) when the liquid crystal display device is turned off.
FIG. 9 shows a driving circuit of a liquid crystal display device of a conventional liquid crystal display device.
As can be seen from FIGS. 9 and 8, the liquid crystal display device of this embodiment is different from the conventional liquid crystal display device in that the circuits A to C shown in FIG. 8 are added.

The operation when the power supply of the liquid crystal display device of this embodiment is turned off will be described below.
When the reset signal (RST) becomes L level, the NAND circuit (NANDc) outputs a High level (hereinafter, H level), and the level shift circuit (LS3) outputs an H level. Then, the level shift circuit (LS4) causes the voltage of the pixel potential control line (Cstt) to become L level. The voltage on the high potential side of the level shift circuit (LS4) is VPP.
Similarly, when the reset signal (RST) becomes L level, the H level is output from the NAND circuit (NANDb), and the L level is input to the level shift circuit (LS2). Then, the H level is output from the level shift circuit (LS2), the L level is set by the inverter, the active element 30 is turned on, and the drain line (D) and the pixel electrode 5 are conducted.
Similarly, when the reset signal (RST) becomes L level, the H level is output from the NAND circuit (NANDa), and the L level is input to the level shift circuit (LS1). The level shift circuit (LS1) outputs an L level to the PMOS side of the analog switch (SWT) and an H level to the NMOS side, the analog switch (SWT) is turned on, and the drain line (D) The video lines (Video 1 to Video 8) are turned on.
Similarly, when the reset signal (RST) becomes L level, the P-type MOS transistor (PMd) opposite to the analog switch (SWT) in the drain line (D) is turned on, and the voltage of VCOM is applied to the drain line (D). As a result, the pixel electrode 5 and the counter electrode 6 are set to the same potential.

As described above, in this embodiment, when the power of the liquid crystal display device is turned off, strict control for controlling the order and time of turning off the power by the external drive circuit is not required.
Further, when the power supply of the liquid crystal display device is turned off, the pixel electrode 5 and the counter electrode 6 are set to the same potential, and the liquid crystal capacitance (Clc) between the pixel electrode 5 and the counter electrode 6 is completely discharged. In addition, it is possible to prevent the liquid crystal composition 3 from being deteriorated by applying a direct voltage (DC) to the liquid crystal composition 3, and to uniformly return the entire display unit to the initial normally white state.
In addition, conventionally, in order to short-circuit the counter electrode and the video line terminal externally during the manufacturing process of the liquid crystal display device or during storage of the liquid crystal display device, a short-circuit socket or a short-circuit tape was required. In this embodiment, a short-circuit socket and a short-circuit tape are not required, and labor (man-hours) and material costs can be reduced.
As mentioned above, the invention made by the present inventor has been specifically described based on the above embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Of course.

1 is a block diagram showing a projector that uses three RGB reflective liquid crystal display devices according to an embodiment of the present invention. FIG. It is sectional drawing for demonstrating the structure of the reflection type liquid crystal display device of the Example of this invention. It is a graph which shows the light absorbency of the visible light band of an alignment film, and the wavelength of an absorption edge. It is a figure for demonstrating the correction effect of a twist angle. It is a figure for demonstrating the correction effect of a twist angle. It is a figure for demonstrating the correction effect of a twist angle. It is a graph which shows the relationship between the control twist angle and the contrast when the rubbing angle is offset during the rubbing process, with and without the phase correction plate. It is a circuit diagram which shows the drive circuit of the liquid crystal display device of the Example of this invention. It is a circuit diagram which shows the drive circuit of the conventional liquid crystal display device.

Explanation of symbols

1 Drive circuit board (silicon)
2 Transparent substrate (glass)
3 Liquid crystal composition 4 Spacer 5 Reflective electrode (pixel electrode)
6 Counter electrode 7, 8 Alignment film 10 Lamp 11 IR filter 12 UV filter 13 Dichroic mirror 14R, 14G, 14B Polarizing plate 15R, 15G, 15B Polarizing beam splitter 16R, 16G, 16B Phase plate 17R, 17G, 17B Reflective liquid crystal display Device 18 Half mirror 19 Exit lens 20 Projection screen 30 Active element 31 First electrode 34 Source region 35 Drain region 36 Gate region 38 Insulating film 40 Second electrode 41 First interlayer film 42 First conductive film 43 Second Interlayer film 44 first light shielding film 45 third interlayer film 46 second light shielding film 42CH through hole 47 fourth interlayer film 48 second conductive film 49 conductive layer 100 liquid crystal display panel 120 horizontal drive circuit 130 vertical drive Circuit 135 Inside gate-off auxiliary circuit 150 Alternating scanning circuit D drain lines (video lines)
G Gate line (scanning line)
Cst pixel potential control line Clc liquid crystal capacitance Cst pixel capacitance Video1 to Video8 Video line LS1 to LS4 Level shift circuit SWT Analog switch PMd, PMg p-type MOS transistor NANDa, NANDb, NANDc NAND circuit

Claims (13)

A pair of substrates comprising a first substrate and a second substrate;
A pair of alignment films disposed on the pair of substrates;
A liquid crystal display panel having a liquid crystal layer sandwiched between the pair of alignment films,
The pair of alignment films is composed of a material mainly composed of all aliphatic polyimide or aliphatic polyimide,
Among the pair of substrates, in a state where the first substrate is disposed on the display surface side of the liquid crystal display panel, the first liquid crystal display panel from the rubbing direction of the alignment film on the first substrate, 2. A liquid crystal display device, wherein an angle of a clockwise crossing angle to the rubbing direction of the alignment film on the substrate 2 is smaller than 90 °.   A crossing angle in a clockwise direction from the rubbing direction of the alignment film on the first substrate to the rubbing direction of the alignment film on the second substrate is 80 ° or more and less than 90, The liquid crystal display device according to claim 1.   The liquid crystal display device according to claim 1, wherein the liquid crystal display panel is a blue reflective liquid crystal display panel.   The liquid crystal display device according to any one of claims 1 to 3, further comprising a phase correction plate disposed on a display surface side of the liquid crystal display panel.   The liquid crystal display device according to claim 4, wherein the phase correction plate is a λ / 4 wavelength plate. The first substrate is a glass substrate;
6. The liquid crystal display device according to claim 1, wherein the second substrate is a silicon substrate. A liquid crystal display panel having a plurality of pixels, a plurality of video lines, and a plurality of scanning lines;
Each of the pixels includes an active element, a pixel electrode connected to the other terminal of the active element, and a counter electrode to which the voltage of VCOM is applied, facing the pixel electrode across the liquid crystal layer,
The plurality of video lines are liquid crystal display devices connected to one terminal of an active element of each pixel,
A means 1 for applying a selection voltage to all the scanning lines to turn on the active elements of all the pixels when a reset signal becomes valid, and a means 2 for applying a VCOM voltage to the plurality of video lines. A liquid crystal display device comprising: Each of the pixels includes a pixel potential control line, and a pixel capacitor element having one terminal connected to the pixel electrode and the other terminal connected to the pixel potential control line.
8. The liquid crystal display device according to claim 7, further comprising means for applying a low level voltage to all of the pixel potential control lines when the reset signal becomes valid. A video line supplied with video voltage;
Switching means for connecting the video line to the video line,
9. The liquid crystal display device according to claim 7, further comprising means for turning on the switching means when the reset signal becomes valid.   10. The liquid crystal display device according to claim 7, wherein the reset signal is effective when a power source of the liquid crystal display device is turned off. A light source;
A plurality of liquid crystal display devices for modulating light emitted from the light source;
A projector including a screen on which light modulated by each liquid crystal display device is projected,
11. The projector according to claim 1, wherein one of the plurality of liquid crystal display devices is the liquid crystal display device according to claim 1. A light source;
A plurality of liquid crystal display panels that modulate light emitted from the light source;
A projector including a screen on which light modulated by each liquid crystal display panel is projected,
The plurality of liquid crystal display panels include a pair of substrates including a first substrate and a second substrate,
A pair of alignment films disposed on the pair of substrates;
A liquid crystal layer sandwiched between the pair of alignment films,
One liquid crystal display panel among the plurality of liquid crystal display panels is configured such that the pair of alignment films is made of a material mainly composed of all aliphatic polyimide or aliphatic polyimide,
Alignment on the second substrate from the rubbing direction of the alignment film on the first substrate in a state where the first substrate is disposed on the display surface side of the plurality of liquid crystal display panels among the pair of substrates. A projector characterized in that the angle of the clockwise crossing angle to the rubbing direction of the film is smaller in the one liquid crystal display panel than in the other liquid crystal display panel. The plurality of liquid crystal display panels are three liquid crystal display panels for red, green, and blue,
The projector according to claim 12, wherein the one liquid crystal display panel is a blue liquid crystal display panel.

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