JPH10142605A - Projection type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure and assembling, suppress the generation of discrimination to reduce the deterioration of display image quality by providing a phase plate whose crystal axis is oriented so that the polarizing direction of the incident light on a display element has a specified angle to the orienting direction of the liquid crystal. SOLUTION: The readout light L1 from a light source 1 is incident on a polarizing beam splitter 2 to separate the light to two mutually orthogonal linear polarized components (S-wave, P-wave) by the polarizing plate 3 of time polarizing beam splitter 2. The read light of one component thereof, for example, S-wave is read and passed through a phase plate 25, whereby the S-wave is rotated by a prescribed angle, and incident on a display element 4. The read light modulated by the liquid crystal of the display element 4 is reflected by the information light, and projected to a screen 6 by a projecting lens 5 after passed through the phase plate 25 and the polarizing beam splitter 2. In this case, the crystal axis of the phase plate 25 is oriented so as to be incident at 45 deg. to the orienting direction of the liquid crystal of tire display element 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal display device using a liquid crystal reflection type display element.

[0002]

2. Description of the Related Art In general, as a projection type display device, a display device using a liquid crystal reflective element is known. This display device utilizes the property that, by projecting polarized light onto a liquid crystal reflective element, light modulated according to a display image is reflected and emitted as information light. Is extracted by a polarizing beam splitter and projected on a screen to display a projected image.

[0003] This will be described with reference to FIGS. 8 and 9. The reading light L 1 from the light source 1 is applied to the polarization beam splitter 2.
To the polarizing plate 3 of the polarizing beam splitter 2.
Then, the light is separated into two linearly polarized light components (S-wave and P-wave) orthogonal to each other, and readout light of a predetermined polarization direction, for example, S-wave is incident on the display element 4. The read light modulated by the liquid crystal layer of the display element 4 is reflected as information light, and is projected on the screen 6 by the projection lens 5. The configuration of the display element 4 is shown in FIG.
0, a pixel electrode substrate 8 on which pixel electrodes 7 are formed in a matrix and a transparent substrate 10 on which transparent electrodes 9 are formed are opposed to each other via a spacer 11, and a liquid crystal 12 is sealed therebetween. I have. Alignment films 13 and 14 for aligning the liquid crystal 12 in a predetermined direction are formed on the respective surfaces of the two substrates 8 and 10.

As the pixel electrode substrate 8, for example, FIG.
The active matrix substrate structure shown in FIG. 1 can be used. FIG. 11 shows an equivalent circuit of an active matrix type substrate configuration. The signal electrode drive circuit 15 samples a video signal (display signal) corresponding to the horizontal arrangement of pixels and supplies the signal to the signal electrode 16. Scan electrode 1
A scanning pulse corresponding to one scanning line period is sequentially supplied to the scanning electrode driving circuit 7 from the scanning electrode driving circuit 18, and a signal is written through each pixel switching transistor Tr. In addition, 1 in the figure
Reference numeral 9 denotes an auxiliary capacitor for holding electric charges applied to the liquid crystal 12,
Hs is a horizontal synchronization signal, Vs is a vertical synchronization signal, and CLK is a reference clock.

FIG. 12 shows a configuration example for one pixel of a pixel electrode substrate. The pixel electrode 7 is formed so as to cover the switching transistor Tr of each pixel.
r is shielded, and a high aperture ratio is realized. Further, if necessary, a light reflection layer of a dielectric multilayer film can be formed on the pixel electrode. Although the switching transistor Tr is constituted by a MOS transistor on a semiconductor substrate in this drawing, it may be formed by a thin film transistor on a semiconductor or an insulating substrate. Also, n, p in the figure
Indicates the type of semiconductor.

FIG. 13 shows the relationship between the pixel arrangement and the liquid crystal alignment in a conventional liquid crystal display device. As an example,
The liquid crystal is assumed to be vertically aligned. In vertical alignment, the movement of liquid crystal molecules during voltage application is aligned in a certain direction.
Alignment is performed with a slight inclination angle (pretilt angle) θ with respect to a direction perpendicular to the pixel electrode substrate 8. This is illustrated in FIG. In FIG. 14, the liquid crystal molecules 2 indicated by arrows are shown.
The alignment direction of 0 is a direction in which the pretilt is provided, and conventionally, the alignment direction is set to a direction of approximately 45 degrees with respect to the horizontal and vertical pixel electrode arrangement.

[0007]

If the liquid crystal alignment direction and the electrode arrangement direction are different from each other as described above, the image quality is degraded due to the lateral electric field as described below. FIG. 15 shows a mode of an electric field distribution generated in the liquid crystal 12 by the signal voltage held in the pixel electrode 7. The liquid crystal 12 is originally driven by a vertical electric field (electric field component perpendicular to the pixel electrode surface) 21 between the transparent electrodes 10 facing each pixel electrode. However, in addition to the vertical electric field component, a horizontal electric field 22 is generated between adjacent pixel electrodes in the horizontal or vertical direction based on the potential difference between the two.

FIG. 16A shows the relationship between the direction of the horizontal electric field 22 generated by the adjacent pixel electrodes and the orientation of the liquid crystal. Horizontal electric field components _EX1 and _{EX2 in} two directions corresponding to the horizontal and vertical arrangement of the pixel electrodes are applied to the liquid crystal. These two lateral electric field component E _X1, E _X2 is Izure also have a direction different from the orientation (pretilt direction) of liquid crystal. As a result, as shown in FIG. 16B, a defective display portion called a disclination 23 mainly occurs on two sides around the pixel electrode 7. The disclination 23 is generated when liquid crystal molecules move in a direction other than the direction of the pretilt due to the influence of a lateral electric field, and significantly degrades the display image quality, such as a decrease in display contrast and a decrease in substantial aperture ratio due to floating black. .

In particular, in the conventional liquid crystal display element, this disclination occurs on both the short side and the long side of the rectangular pixel electrode, and the effect is particularly large in the direction of a small pixel arrangement pitch. . In addition, as shown in FIG. 17, when the pixel electrodes are arranged in a stripe shape corresponding to the three primary colors of RGB light and color display is realized by a single plate element, adjacent pixels in the horizontal direction are different. Color.
As a result, for example, in the case of performing full-screen red display, a potential difference between pixels is generated between the R pixel electrode (lit) and the G and B pixel electrodes (non-lit), and a uniform display image is obtained. Also, there is a problem that the display image quality is easily degraded due to the disclination. Normally, in the horizontal direction in which adjacent pixels are repeatedly arranged in RGB, the pixel arrangement pitch itself is smaller than in the vertical direction in which pixels of the same color are arranged, and the degree of influence of display quality deterioration due to the disclination also increases. .

In the circuit configuration of a general active matrix type liquid crystal display device as shown in FIG. 11, writing of a video signal to each pixel is performed at a field or frame period of the video signal. In order to drive the liquid crystal by AC, the polarity of the signal is inverted. Thus, each pixel is １ ／ of the field or frame frequency.
(30 Hz / 15 Hz) low-frequency AC voltage, and there is a problem that flicker (image flicker) becomes conspicuous if there is asymmetry due to polarity. As a countermeasure for this problem, FIGS. As shown in (1), a driving method is adopted in which the polarities + and-of the voltage of the video signal are inverted for each adjacent pixel. Each cell in the figure indicates a pixel to a pixel electrode. FIG. 18A shows a state in which the polarity is inverted for each column, and FIG. 18B shows a state in which the polarity is inverted for each row. FIG. 18C shows a state in which rows and columns are mixed and the polarity is inverted.

FIG. 19 shows a circuit configuration of a display element for driving the polarity inversion in this manner. The difference from FIG. 11 is that two signal electrode drive circuits 15A and 15B are provided. One of the signal electrodes 16, for example, the odd-numbered (1, 3, 5,...) One signal electrode driving circuit 15A
, On the other hand, for example, even-numbered (2, 4, 6,...)
Is connected to the other signal electrode drive circuit 15B. A first polarity inversion circuit 33 is interposed between these drive circuits 15A and 15B as means for inverting and supplying a signal.
As a result, video signals of opposite polarities are input to both drive circuits 15A and 15B.

In the circuit configuration of the illustrated example, as a result,
The polarity of the video signal of each pixel is inverted for each column as shown in FIG. In the illustrated example, when the video signal passed through the second polarity inversion circuit 34 is inverted at an appropriate cycle such as a field or a frame by the switch unit 35, if it is inverted at a line cycle, for example, as shown in FIG. It becomes a polarity inversion drive. By inverting the polarity for each pixel in this manner, flicker is also averaged, and this can be reduced visually.

However, even when the above-described driving method is used, since a signal of opposite polarity is supplied between adjacent pixels, the potential difference between adjacent pixels also increases. Therefore, there is a problem that the horizontal electric field between the pixels also becomes large, and the display quality is likely to deteriorate due to the disclination as described above. In view of the above, the applicant of the present invention has disclosed in the prior application (Japanese Patent Application No. Hei 7-166880) that the display element is rotated by 45 degrees around the optical axis with respect to the polarizing beam splitter so that the light is reflected from the display element. A technique has been disclosed in which the polarization direction of information light is inclined by 45 degrees, thereby suppressing the occurrence of disclination.
However, in this case, since the display element and the polarizing beam splitter are provided in a state rotated by 45 degrees, the display element becomes oblique in order to take all the information light reflected from the display element into the polarizing beam splitter. There is a problem that the length of one side of the shaped polarizing beam splitter becomes longer, and it is quite difficult to accurately set a 45 ° angle in an optical system that is small and complicated. A new problem was found. The present invention focuses on the above-mentioned conventional problems, and was conceived to effectively solve the problems. The purpose of the present invention is to simplify the structure and assembly, suppress the occurrence of disclination, and reduce the display image quality. It is an object of the present invention to provide a projection-type liquid crystal display device having a small number of pixels.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a display element for modulating a linearly polarized light component based on a display signal, and a linearly polarized light component of read light from a light source to the display element. A projection-type liquid crystal display device having an incidence unit for making incident, and a projection unit for projecting read light reflected by the display element onto a screen, wherein the display element has a plurality of rectangular pixel electrodes arranged in a matrix. A pixel electrode substrate, a transparent substrate disposed opposite to the pixel electrode substrate and having a transparent electrode formed thereon, a liquid crystal sealed between the transparent substrate and the pixel electrode substrate, and the liquid crystal in a predetermined direction. In the projection type liquid crystal display device provided with an alignment unit for aligning, the alignment direction of the liquid crystal by the alignment unit is substantially parallel or substantially perpendicular to a direction of a side of the rectangular pixel electrode. The crystal axis is oriented between the incident means and the display element such that the polarization direction of light incident on the display element is incident at an angle of 45 degrees with respect to the alignment direction of the liquid crystal. It is configured to provide a phase plate attached thereto.

According to the present invention, the orientation of the liquid crystal is substantially parallel or substantially perpendicular to the side of the rectangular pixel electrode, and is incident on the display element by the action of the phase plate. Since the reading light can be incident with its polarization direction inclined at 45 degrees with respect to the alignment direction of the liquid crystal, disclination occurs only at the side portion where the two are in a perpendicular relationship. The effect of disclination can be suppressed as compared with a conventional device in which disclination has occurred on both sides. In particular, by setting the relationship between the liquid crystal alignment direction and the pixel arrangement direction such that the portion where disclination occurs is on the short side of the pixel electrode, the influence of disclination can be further suppressed. In this case, the crystal axis of the phase plate is inclined by 22.5 degrees with respect to the polarization direction of the reading light.

A color display element whose pixel electrode corresponds to the three primary colors of light can also be used as a display element.
Further, a device using a microlens array as a color display element can be employed. In addition, as a driving method of the display element, a driving method in which a display signal whose polarity is inverted for each adjacent pixel electrode is applied can be adopted.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the projection type liquid crystal display device according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a perspective view showing a projection type liquid crystal display device of the present invention, FIG. 2 is a block diagram of the display device shown in FIG. 1, and FIG. 3 is a display according to a first example of the projection type liquid crystal display device of the present invention. FIG. 4 is a diagram showing the relationship between the pixel electrode substrate and the pixel electrode of the device, and FIG. 4 is a diagram showing the relationship between the lateral electric field of the display device of FIG. 3 and the alignment direction of the liquid crystal. Note that the same parts as those of the above-described apparatus example are denoted by the same reference numerals and described.

First, the general configuration of the projection type liquid crystal display device of the present invention is the same as that shown in FIGS. 8 to 12 except that a phase plate characteristic of the present invention is provided between the display element and the incident means. Is completely the same as that shown in FIG. 1, and the overall configuration will be described first. That is, as shown in FIGS. 1 and 2, the projection type liquid crystal display device converts the display element 4 that modulates the linearly polarized light component based on the display signal and the readout light L1 from the light source 1 into two linearly polarized light components. A polarizing beam splitter 2 as an incident means for entering the display element, a projection lens 5 as a projecting means for projecting a reading light (information light) reflected by the display element 4 onto a screen 6, and the polarizing beam splitter 2 And a phase plate 25 interposed between the display element 4.

Here, the readout light L1 from the light source 1 is made incident on the polarizing beam splitter 2, and is separated by the polarizing plate 3 of the polarizing beam splitter 2 into two linearly polarized components (S-wave and P-wave) orthogonal to each other. Then, one polarization component, for example, the readout light of the S wave is extracted, and the readout light is passed through the phase plate 25 to rotate the S wave by a predetermined angle.
This is incident on the display element. The reading light modulated by the liquid crystal of the display element 4 is reflected as information light, and is reflected by the phase plate 2.
After passing through the polarizing beam splitter 2 and the projection lens 5, the light is projected on the screen 6 by the projection lens 5. Here, the phase plate 25
The crystal axis is oriented such that the polarization direction of the incident light (readout light) L1 to the display element 4 is incident at 45 degrees with respect to the alignment direction of the liquid crystal of the display element 4.
For example, a half-wave plate can be used as the phase plate 25, and the crystal axis direction of the phase plate 25 is set to be inclined by 22.5 degrees with respect to the polarization direction of the S wave. The configuration of the display element 4 is shown in FIG. 10, in which a pixel electrode substrate 8 on which pixel electrodes 7 are formed in a matrix and a transparent substrate 10 on which a transparent electrode 9 is formed are opposed to each other via a spacer 11. The liquid crystal 12 is sealed between them. Alignment films 13 and 14 for aligning the liquid crystal 12 in a predetermined direction are formed on the respective surfaces of the two substrates 8 and 10.

As the pixel electrode substrate 8, for example, FIG.
The active matrix substrate structure shown in FIG. 1 can be used. The signal electrode drive circuit 15 samples a video signal (display signal) corresponding to the horizontal arrangement of pixels and supplies the signal to the signal electrode 16. A scan pulse corresponding to one scan line period is sequentially supplied from the scan electrode drive circuit 18 to the scan electrode 17, and each pixel switching transistor Tr
The signal is written via. In the figure, 19 is the liquid crystal 12
Hs is a horizontal synchronizing signal, Vs is a vertical synchronizing signal, and CLK is a reference clock.

FIG. 12 shows a configuration example for one pixel of the pixel electrode substrate. The pixel electrode 7 is formed so as to cover the switching transistor Tr of each pixel.
r is shielded, and a high aperture ratio is realized. Further, if necessary, a light reflection layer of a dielectric multilayer film can be formed on the pixel electrode. Although the switching transistor Tr is constituted by a MOS transistor on a semiconductor substrate in this drawing, it may be formed by a thin film transistor on a semiconductor or an insulating substrate. Also, n, p in the figure
Indicates the type of semiconductor.

In the pixel electrode substrate 8, the rectangular pixel electrodes 7 are arranged such that their sides are respectively parallel to the vertical and horizontal sides of the rectangular pixel electrode substrate 8. The alignment direction A is also set so as to be substantially parallel to the long side direction of each pixel electrode. The short side of the pixel electrode is, of course, substantially perpendicular to the alignment direction A.

In this case, the opposing sides of the adjacent pixel electrodes are set to be substantially parallel or substantially perpendicular to the liquid crystal alignment direction. That is, in the illustrated example, each long side of the pixel electrode 7 is substantially parallel to the liquid crystal alignment direction A. In this case, as a matter of course, the short side of the pixel electrode 7 is a direction substantially perpendicular to the liquid crystal alignment direction A. The information signal (video signal) is, for example, a signal of the first scan electrode (1, 1) by the circuit configuration shown in FIG.
(1, 2),... (1, i) are written to the pixel electrodes 7, and the second scanning electrode signals are written in (2, 1), (2, 2),.
Writing to each of the pixel electrodes 7 in (2, i) may be performed in the same manner.

Next, the operation of the present embodiment configured as described above will be described. As shown in FIGS. 1 and 2, a readout light L1 emitted from a light source 1 enters a polarizing beam splitter 2 and is polarized by a polarizing plate 3 into S-waves and P-waves. Are transmitted, and the S-wave is reflected and transmitted through the phase plate 25 before going to the display element 4. In the display element 4, the reading light of the S wave is modulated based on the information signal by the function of the liquid crystal, and is reflected as the information light L2. As a result of the modulation, the information light L2 includes not only the S wave but also the P wave. The S wave is reflected by the polarizing plate 3 of the polarization beam splitter 2, and only the P wave of the modulation component is transmitted. Is projected onto the screen 6 by the projection lens 5, and an image is projected.

Here, the readout light L1 is S-wave rotated by a predetermined angle by the phase plate 25 composed of a half-wave plate, and in the display element 4, as shown in FIG. Since the direction is set so as to be substantially parallel to the liquid crystal alignment direction A, it is possible to greatly suppress the influence of disclination of the displayed image. That is, FIG.
(A) shows a horizontal electric field component _EX1 generated between the pixel electrodes 7,
FIG. 4 is a diagram showing the relationship between _EX2 and the liquid crystal orientation direction A.
(B) is a diagram showing the state of occurrence of disclination at that time. Note that the polarization direction of the reading light is a 45-degree oblique direction in the drawing. Transverse electric field component E _X1, E _X2 in FIG. 4 (A), respectively occurs along the long side direction and the short side direction of the pixel electrode, in this case, transverse electric field component E _X1 in the long side direction, the liquid crystal Since it is substantially parallel (approximately 180 degrees) to the orientation direction A, disclination does not occur in this portion. On the other hand, the transverse electric field component _EX2 in the short-side direction is substantially perpendicular to the liquid crystal alignment direction A, so that the disclination 23 occurs in this portion.

Here, the operation of the phase plate 25 will be described in detail with reference to FIG. Here, a half-wave plate is used as the phase plate 25 as described above, and the polarizing plate 3
The S-wave readout light L <b> 1 (FIG. 5A) reflected by the light enters the phase plate 25. At this time, the direction of the crystal axis 26 of the phase plate 25 is set to be inclined by 22.5 degrees with respect to the polarization direction of the S-wave (FIG. 5B). Therefore, when transmitted through the phase plate 25, the light is rotated in a direction inclined 45 degrees counterclockwise from the polarization direction of the initial S wave (FIG. 5).
(C)) Therefore, when the transmitted light is incident on the reflective liquid crystal display element 4, the polarization direction is 4 with respect to the alignment direction A of the liquid crystal.
Light can be incident at an angle of 5 degrees.

On the other hand, the information light reflected by the reflection type liquid crystal display element 4 is output after being rotated by about 90 degrees in the polarization direction due to the optical anisotropy of the liquid crystal (FIG. 5 (E)). / 2 wavelength plate) 25 (FIG. 5F). At this time, polarized light inclined by 22.5 degrees with respect to the crystal axis 3 of the phase plate 25 is incident, and when transmitted through the phase plate, it is rotated clockwise by 45 degrees (FIG. 5 (G)). Therefore, the polarizing plate 3
Will be detected as a P-wave. That is, returning to FIG. 1 and FIG.
1 enters the polarization beam splitter 2 and reflects the S-polarized light component. The readout light L1 reflected from the polarization beam splitter 2 passes through a phase plate 25 composed of a half-wave plate whose crystal axis is inclined by 22.5 degrees, and enters the reflection type liquid crystal display element 4. The light incident on the reflective liquid crystal element 4 is modulated by the liquid crystal in the element, reflected and reflected again by the phase plate 25.
And enters the polarization beam splitter 2. At this time, the information light L2 incident on the polarization beam splitter 2 is
Since it is a P-wave, it passes through the polarization beam splitter 2 without being reflected by the polarization beam splitter 2, and a good image which is not affected by disclination is projected by the projection lens 5.

FIG. 16 shows the case of the conventional apparatus.
As is clear from the comparison with (B), in the present invention, the portion where the disclination occurs is only one side of the peripheral portion of the pixel electrode, and as a result, the influence of the disclination is suppressed and the image quality is degraded. Can be prevented and this can be greatly improved. In the illustrated example, the long side of the pixel electrode is set to be substantially parallel to the liquid crystal alignment direction A. However, the present invention is not limited to this, and the short side may be set to be substantially parallel to the liquid crystal alignment direction A. Good. In this case, if the arrangement direction of the pixel electrodes 7 is the same in FIGS. 1 and 2, the liquid crystal alignment direction may be set to the direction shown by the arrow B. Furthermore,
Needless to say, the liquid crystal alignment directions may be opposite by 180 degrees to the arrows A and B, respectively.

Next, a display device according to a second embodiment of the present invention will be described. FIG. 6 is a diagram showing a relationship between a pixel electrode substrate and a pixel electrode of a display element according to the second embodiment.
This embodiment is an element for performing color display, and the pixel electrodes 7 are arranged in the same manner as in the first embodiment shown in FIG. Since color display is performed, each pixel electrode is allocated in the horizontal direction so as to correspond to the three primary colors of RGB light so as to repeat this order. As a result, the arrangement direction (stripe direction) of the same-color pixel electrodes is set so as to be substantially parallel to the liquid crystal alignment direction A, so that the side where disclination occurs is only the side in the arrangement direction of the same-color pixels. 4 (B)), therefore, it is possible to suppress the occurrence of disclination between pixels of different colors in which a potential difference between pixels easily occurs, and it is possible to obtain a high quality color display image. In the above embodiment, the phase plate 25 is provided separately from the display element 4 and the polarizing beam splitter 2. However, the present invention is not limited to this, and the phase plate 25 is provided in the display element 4 as shown in FIG. It may be incorporated and arranged on the light incident side of the liquid crystal 12 to make the device compact.

The present invention can be applied not only to an active matrix type liquid crystal display device as shown in FIG. 11, but also to a liquid crystal display device of a polarity inversion of video signal voltage as shown in FIG. . Also in this case, by interposing the phase plate with the liquid crystal orientation direction substantially parallel or substantially perpendicular to the sides of the rectangular pixel electrode, the pixel electrode It is possible to reduce the occurrence of disclination in the peripheral portion. Further, in the present embodiment, a case where minute rectangular pixel electrodes are arranged so as to be parallel or perpendicular to the long side and short side of the rectangular pixel electrode substrate is described as an example, but the present invention is not limited to this. Instead, the present invention can be applied to a case where pixel electrodes on a rectangle are arranged in a stripe shape in an oblique direction. The present invention is characterized by the relationship between the alignment direction of the liquid crystal and the pixel arrangement, and the alignment of the liquid crystal is not limited to the birefringence mode by the vertical alignment described in the embodiment, and may be, for example, a reflective display. Needless to say, the present invention can be applied to an HFE mode or the like as a suitable element.

[0031]

As described above, according to the projection type liquid crystal display device of the present invention, the following excellent functions and effects can be exhibited. Since the relationship between the arrangement of the pixel electrodes and the liquid crystal alignment direction is set to be substantially parallel or orthogonal to each other, and the crystal axes of the phase plates are arranged at a predetermined angle, they are generated by a lateral electric field based on the potential difference between adjacent pixels. Disclination at the peripheral portion of the pixel can be reduced. Further, in the single-chip color system, even when different colors are displayed between adjacent pixels, occurrence of disclination due to a potential difference between pixels can be reduced. Therefore, the quality of the displayed image can be significantly improved for the above reasons.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a projection type liquid crystal display device of the present invention.

FIG. 2 is a block diagram of the display device shown in FIG.

FIG. 3 is a diagram showing a relationship between a pixel electrode substrate and a pixel electrode of a display element according to the first embodiment of the projection type liquid crystal display device of the present invention.

FIG. 4 is a diagram showing a relationship between a lateral electric field of the display element of FIG. 3 and an alignment direction of liquid crystal.

FIG. 5 is a diagram illustrating the behavior of polarized light when a half-wave plate is used as a phase plate.

FIG. 6 is a diagram illustrating a relationship between a pixel electrode substrate and a pixel electrode of a display element according to a second example.

FIG. 7 is a diagram showing a structure when a phase plate is incorporated in a display element.

FIG. 8 is a schematic perspective view showing a general projection type liquid crystal display device.

9 is a block diagram of the display device shown in FIG.

FIG. 10 is a cross-sectional view showing a general display element used in the device shown in FIG.

11 is an equivalent circuit diagram of the display element shown in FIG.

12 is a sectional view showing a pixel electrode substrate of the unit pixel shown in FIG.

FIG. 13 is a plan view showing a conventional arrangement of a pixel electrode and a pixel electrode substrate.

FIG. 14 is an explanatory diagram showing a tilt state of liquid crystal molecules.

FIG. 15 is an explanatory diagram illustrating a horizontal electric field generated between pixel electrodes.

FIG. 16 is an explanatory diagram illustrating a cause of disclination occurring in a pixel electrode.

FIG. 17 is a plan view showing a conventional arrangement state of color pixel electrodes.

FIG. 18 is a diagram illustrating the polarity of a pixel during polarity inversion driving of a video signal.

FIG. 19 is a circuit configuration diagram when performing polarity inversion driving of a video signal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source, 2 ... Polarization beam splitter (incident means), 4
... Display element, 5 ... Projection lens (projection means), 6 ... Screen, 7 ... Pixel electrode, 8 ... Pixel electrode substrate, 9 ... Transparent electrode, 10 ... Transparent substrate, 12 ... Liquid crystal, 13,14 ... Alignment film (Alignment) Means), 15: Signal electrode drive circuit, 16: Signal electrode, 17: Scan electrode, 18: Scan electrode drive circuit, 2
5: phase plate, 26: crystal axis, A: liquid crystal alignment direction, _EX1 ,
_EX2 : lateral electric field component, L1: readout light.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 5/74 H04N 5/74 K // H04N 9/31 9/31 C

Claims (5)

[Claims] 1. A display element for modulating a linearly polarized light component based on a display signal, an input means for inputting a linearly polarized light component of readout light from a light source to the display element, and a screen for reading the readout light reflected by the display element. A projection-type liquid crystal display device having projection means for projecting light onto a pixel electrode substrate in which a plurality of rectangular pixel electrodes are arranged in a matrix, and the display element is disposed so as to face the pixel electrode substrate and is transparent. A projection type liquid crystal display device comprising: a transparent substrate having electrodes formed thereon; a liquid crystal sealed between the transparent substrate and the pixel electrode substrate; and an alignment unit for aligning the liquid crystal in a predetermined direction. The alignment direction of the liquid crystal by the alignment unit is set so as to be substantially parallel or substantially perpendicular to the direction of the side of the rectangular pixel electrode, and between the incident unit and the display element. And a phase plate having a crystal axis oriented such that a polarization direction of light incident on the display element is incident at an angle of 45 degrees with respect to an alignment direction of the liquid crystal. Liquid crystal display. 2. The projection type liquid crystal display device according to claim 1, wherein the phase plate is arranged so that a crystal axis thereof is inclined by 22.5 degrees with respect to a polarization direction of the readout light. 3. The method according to claim 1, wherein each of the plurality of pixel electrodes has a light intensity of three.
Pixel electrodes corresponding to one of the primary colors and corresponding to the same color in the first direction are arranged in the same line, and the second direction indicating a predetermined angle with respect to the first direction. Are arranged such that pixel electrodes corresponding to respective colors are arranged in a predetermined repetition order, and the alignment direction of the liquid crystal is substantially parallel or substantially perpendicular to the first direction in which pixel electrodes of the same color are arranged. 3. The projection-type liquid crystal display device according to claim 1, wherein: 4. A microlens array corresponding to a pixel arrangement for causing readout light of a corresponding color to be incident on the arrangement of the pixel electrodes of each color. 4. The projection type liquid crystal display device according to 3. 5. The projection type liquid crystal according to claim 1, further comprising an inversion supply unit for supplying a display signal of which polarity is inverted for each of the adjacent pixel electrodes in the arrangement of the pixel electrodes. Display device.