JPH06138478A - Two-layer type liquid crystal display device and projection type display device using the same - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display device which executes an excellent black display and has no orientation disorder and the projection type display device using it. CONSTITUTION:This device is equipped with a 1st liquid crystal panel 23a and a 2nd liquid crystal panel 23b which are arranged closely to each other so that twisted nematic liquid crystal molecules are twisted in mutually opposite directions and so constituted that incident light is passed through the liquid crystal layer 14 of the 1st liquid crystal panel 23a and the liquid crystal layer 15 of the 2nd liquid crystal panel 23b and projected; and a pixel electrode 16 is formed on the 1st liquid crystal panel 23a and the orientation state of the liquid crystal of the liquid crystal layer 14 of the 1st liquid crystal panel 23a can be varied with a signal applied to the pixel electrode 16. The 2nd liquid crystal panel 23b has an orienting film 19 on the surface opposite the liquid crystal layer 15 and transparent conductive thin films 18a and 18b are formed on respective orienting films 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device for enlarging and projecting an image displayed on a small liquid crystal panel on a screen and a two-layer type liquid crystal display device mainly used for the projection type display device. .

[0002]

2. Description of the Related Art Since a liquid crystal panel has many advantages such as light weight and thin shape that can be used for display, research and development as a display device has been active. However, there are many problems such as difficulty in increasing the screen size. Therefore, in recent years, a projection type display device (hereinafter referred to as a liquid crystal projection type television), which obtains a large-screen display image by enlarging and projecting a display image of a small-sized liquid crystal display device, has been attracting attention. At present, a twisted nematic (hereinafter referred to as TN) liquid crystal display device that utilizes the optical rotation property of liquid crystal is used in a liquid crystal projection television that has been commercialized. JP-A-2-53030 is known as such a conventional liquid crystal projection television and a liquid crystal display device used therefor.

FIG. 9 is a block diagram of the conventional projection television. In the figure, the light emitted from the light source 82 is reflected by the concave mirror 81 and then condensed by the condenser lens 83. The light is separated into three lights of red, green, and blue by dichroic mirrors 84a and 84b, and a liquid crystal display device having a two-layer structure (hereinafter referred to as a two-layer liquid crystal display device) 90a, 9 is formed.
0b and 90c respectively enter. R, G, and B in the figure indicate the optical paths of red light, green light, and blue light, respectively.
An image corresponding to a display pattern is formed by applying a signal voltage to each of the liquid crystal display devices 90a, 90b, and 90c.
0b, 90c images on the projection lens 88a, 88b, 88
A color display is performed by enlarging and projecting at c and combining on the screen 89.

Next, the above-mentioned two-layer liquid crystal display device will be described in detail. FIG. 8 is a sectional view showing the structure of the two-layer liquid crystal display device. In the figure, 74 and 85 are TN type liquid crystal layers in which liquid crystal molecules have opposite twist structures, and the twist angle is about 90 °. Reference numerals 73a and 73b denote polarizing plates, and the polarizing axis of one polarizing plate 73a is substantially parallel (or right angle) to the long axis of the liquid crystal molecule on the lower wall surface of the liquid crystal layer 74 in the figure.
The polarization axis of the other polarizing plate 73b is the polarizing plate 73b.
It is substantially orthogonal to the polarization axis of a.

A liquid crystal panel having a liquid crystal layer 74 on the lower side of FIG. 8 (hereinafter referred to as an image panel) is an image panel for displaying an image based on a video signal, and includes tens of thousands or more pixel electrodes 76a. , 76b and a counter electrode 76c common to each pixel electrode are arranged so as to sandwich the liquid crystal layer 74. In addition, the pixel electrodes 76a and 76b and the counter electrode 7
An alignment film 80 is applied on 6c and subjected to an alignment treatment to align the liquid crystal of the liquid crystal layer 74.

On the other hand, a liquid crystal panel having a liquid crystal layer 75 on the upper side in FIG. 8 (hereinafter referred to as a phase compensation panel) is a phase compensation panel for compensating for the phase difference caused by the above-mentioned image panel, and is a glass substrate 72a. , 72b are directly coated with an alignment film 79, and the alignment film 79 is subjected to an alignment treatment to align the liquid crystal of the liquid crystal layer 75.

In the two-layer liquid crystal display device constructed as described above, light is made incident from the polarizing plate 73a.
Consider a case where it is arranged in the liquid crystal projection television of FIG. First, the incident light is linearly polarized by the polarizing plate 73a and propagates in the liquid crystal layer 74 of the image panel. Liquid crystal layer 7
4 is not applied, the liquid crystal of the liquid crystal layer 74 is
The polarization plane of the light is rotated by about 90 ° in the liquid crystal layer 74, but the light emitted from the liquid crystal layer 74 is not necessarily linearly polarized light. However, depending on the wavelength, it becomes elliptically polarized light, and wavelength dependence also occurs in the major axis direction of the elliptically polarized light. On the other hand, the liquid crystal layer 75 of the phase compensation panel, due to its reverse twist structure, rotates the polarization plane in the opposite direction by approximately 90 ° to compensate the above wavelength dependence. Therefore, the light emitted from the liquid crystal layer 75 becomes linearly polarized light in the same state as the light incident on the liquid crystal layer 74. Since the polarization axis of the polarizing plate 73b is arranged in such a direction as to block this linearly polarized light, the transmittance of the panel is sufficiently low without wavelength dependence when no voltage is applied.
On the other hand, when a sufficiently high voltage is applied to the liquid crystal layer 74, the liquid crystal molecules in this layer are vertically arranged between the pixel electrode 76b and the counter electrode 76c as shown on the right side of FIG. Therefore, the polarization state does not change in the liquid crystal layer 74, and the incident polarized light has its polarization plane rotated by approximately 90 ° in the liquid crystal layer 75 and passes through the polarizing plate 73b. In this case, the same wavelength dependency as in the case of one liquid crystal layer is exhibited, but its influence is small because the overall transmittance is large.

[0008]

However, the conventional two-layer type liquid crystal display device and the liquid crystal projection type television using the same have the following problems. That is, the first problem is the alignment disorder that occurs in the phase compensation panel. An alignment film 79 is formed on the glass substrates 72a and 72b of the phase compensation panel, and an alignment treatment is performed so that the liquid crystal molecules of the liquid crystal layer 75 are twisted by 90 °. If static electricity or the like acts on it from the outside, alignment disorder occurs, and if the alignment disorder occurs, phase compensation of the image panel cannot be performed, and as a result, light leakage occurs. Particularly in a liquid crystal projection television, the liquid crystal panel is heated when the lamp 82 is turned on and is cooled when the lamp 82 is turned off, so that static electricity easily enters the phase compensation panel and the like. Therefore, the orientation disorder due to them is apt to occur, which causes color unevenness in the image display and deteriorates the display quality. In addition, static electricity often enters not only during use but also during manufacturing of liquid crystal display devices.

The second problem is the amount of phase compensation by the phase compensation panel. In a two-layer liquid crystal display device, it is important to make the thickness of the liquid crystal layer of each panel exactly the same, but since the liquid crystal layer is extremely thin, about 5 μm, it is necessary to make the thickness of the liquid crystal layers the same. It is difficult. Particularly, in the liquid crystal panel manufacturing process, a difference in film thickness easily occurs from lot to lot. Using the phase compensation panel and image panel manufactured from such a lot,
It is extremely difficult to combine both panels in the most suitable way. If the liquid crystal film thickness difference between the phase compensation panel and the image panel is different by 0.1 to 0.2 μm, the original black display cannot be realized, and the contrast is significantly reduced. Further, when displaying a color image using three liquid crystal display devices in a liquid crystal projection television, if there is even one liquid crystal display device with poor contrast, the worst liquid crystal display device will have a large effect, resulting in low quality. The image is displayed.

In view of the problems of the conventional two-layer type liquid crystal display device and the projection type display device using the same as described above, the present invention prevents alignment disturbance of the phase compensation panel and controls the amount of phase compensation. It is an object of the present invention to provide a two-layer liquid crystal display device capable of performing the above and a projection display device using the same.

[0011]

According to a first aspect of the present invention, there is provided a first liquid crystal panel for performing light modulation, and compensating for a phase difference generated during the light modulation in the first liquid crystal panel. And a second liquid crystal panel having a substrate, a liquid crystal layer, and electrodes sandwiching the liquid crystal layer.

According to a thirteenth aspect of the present invention, one light source, the two-layer liquid crystal display device according to the first or second aspect which modulates light emitted from the light source, and the two-layer liquid crystal display device are used for modulation. It is a projection display device comprising a projection lens for magnifying and projecting the projected light.

[0013]

According to the two-layer liquid crystal display device of the first aspect, since the second liquid crystal panel for compensating the phase difference has an electrode, the electrode is formed of a transparent electrode, and the transparent electrode is formed. When the alignment film is formed on the electrodes, the potential is stabilized, and it is possible to prevent static electricity from entering one place and disturbing the alignment. Further, if the transparent electrode is drawn to the outside and the potential is grounded, it becomes stronger against static electricity. Further, when an AC signal is applied between the two transparent electrodes that sandwich the liquid crystal layer, the alignment state of the liquid crystal layer in the second liquid crystal panel, that is, the amount of phase compensation can be changed. The phases of the panels can be perfectly matched.

According to the projection type display device of claim 13, 1
One light source, the two-layer liquid crystal display device that modulates the light emitted from the light source, and the projection lens that magnifies and projects the light modulated by the two-layer liquid crystal display device, so that an image is formed. Alignment disorder does not occur in the two-layer liquid crystal display device,
As a result, a good black display can be performed on the projected image and a good contrast can be obtained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention. In addition, in the drawings to be referred to hereinafter, portions unnecessary for description are omitted, and there are enlarged or reduced portions for easy illustration and / or understanding.

In FIG. 1, an image panel 23a as a first liquid crystal panel for performing light modulation includes a glass substrate 11a on which a pixel electrode 16 is formed and a glass substrate on which a counter electrode 22 and a black matrix 17 are formed. 11
b and a liquid crystal layer 14 sandwiched between both glass substrates 11a and 11b. An alignment film 20 is formed on the pixel electrode 16 and the counter electrode 22 to align the liquid crystal molecules of the liquid crystal layer 14. In addition,
The image panel 23a used in this embodiment is an active matrix type liquid crystal panel having a TN structure. This active matrix type liquid crystal panel has high contrast,
Good gradation. In the two-layer liquid crystal display device, S
There is also a system using TN (super twisted nematic), but the gradation display is poor, and it cannot be used in the liquid crystal projection television as in this embodiment.

A phase compensating panel 23b serving as a second liquid crystal panel for compensating for a phase difference generated at the time of light modulation in the image panel 23a includes a glass substrate 12a on which an electrode 18a is formed and an electrode 18b. It is mainly composed of a glass substrate 12b which is formed and a liquid crystal layer 15 sandwiched between the glass substrates 12a and 12b. An alignment film 19 is formed on the glass substrates 12a and 12b to align the liquid crystal in the liquid crystal layer 15.

The electrodes 18a and 18b are formed in a lattice shape as shown in FIG. 2 when shown in a plan view. In the figure, reference numeral 21 denotes an opening (opening), and the opening 21 is the image panel 2
It is preferably formed so as to correspond to the formation position of the pixel electrode 16 in 3a, that is, so as not to interfere with the light emitted from the pixel electrode 16. In addition, the electrodes 18a and 18b are transparent conductive thin films formed of ITO (indium-tin-oxide), and the ITO indicates tin oxide simple substance, indium oxide simple substance, a compound and a mixture of the above substances. is there. The refractive index of ITO is 1.8
~ 2.0 is common. Then, a part of the incident light is reflected by the portion in contact with the substances having different refractive indexes. Such a reflectance R is expressed by the following equation, where n _{1 is} the refractive index of the medium A and n _{2 is} the refractive index of the medium B.

[0020]

[Equation 1]

Now, assuming that the refractive index of ITO is 2.0, the refractive index of glass is 1.5, and the refractive indexes of the alignment film and the liquid crystal are also 1.5, the reflectance R ₁ between the ITO and the glass substrate is R _1. Is 2.0% according to (Equation 1), and the reflectance R ₂ between the ITO and the alignment film is 2.0%. Therefore, one layer of ITO
In the case of, the reflectance R is R = R ₁ + R ₂ = 4%, and since two layers of ITO film are formed for the liquid crystal layer 15,
The total reflectance is 2R = 8%. That is, by forming the ITO film on the phase compensation panel 23b, a light loss of less than 10% is caused. Since such reflection occurs in a region near the light modulation layer of the image panel 23a, if halation due to reflection occurs, the image quality is likely to deteriorate.

In order to prevent such deterioration of image quality, in this embodiment, as shown in FIG. 2, the phase compensation panel 23b is used.
The regions of the electrodes 18a and 18b corresponding to the pixel electrode 16 are opened, thereby reducing the aforementioned reflection. The electrodes 18a and 18b are for preventing alignment disorder due to invasion of static electricity, and the electrodes 18a and 18b are
As shown in FIG. 3, it is preferable to electrically short-circuit by using the conductor 31, and it is preferable to provide two or more connection points as shown in FIG. Examples of the conductive material include conductive paste such as silver paste, conductive adhesive, and carbon.

As described above, the electrodes 18a,
The electrode 1 is configured by short-circuiting between 18b.
8a and 18b can always be set to the same potential, whereby the alignment disorder due to static electricity or the like is extremely reduced.
Further, the point A shown in FIG.
If a and 18b are fixed potentials, it is possible to prevent the alignment disorder from occurring at all.

Alternatively, the electrodes 18a and 18b can be externally drawn out as separate electrode terminals so that an AC voltage can be applied to each electrode. That is, in the conventional liquid crystal display device, it was difficult to completely match the phases of the image panel 23a and the phase compensation panel 23b, but as in the present embodiment, an AC signal is applied to the phase compensation panel 23b to cause a phase difference. If you can adjust
The phase difference between both panels 23a and 23b can be made extremely small, and good black display can be realized. The thickness of the liquid crystal layer 15 of the phase compensation panel 23b is set to be slightly thicker than the thickness of the liquid crystal layer 14 of the image panel 23a.
That is, the liquid crystal layer 15 is set in advance to have a phase larger than that of the liquid crystal layer 14, and an AC signal is transmitted to the liquid crystal layer 1.
5 is applied to reduce the phase of the liquid crystal layer 15, and finally the phase difference between the two panels 23a and 23b is set to zero to adjust the phase difference.

Further, the electrodes 18a and 18b are formed in a lattice shape in order to reduce reflection at the pixel openings as much as possible and improve the transmittance. However, it may be slightly shifted. This is because when the two-layer liquid crystal display device of the present embodiment is used in a liquid crystal projection television, the incident light is not narrow directivity, and light having a constant spread angle of about ± 7 degrees is incident.

Further, the glass substrate 1 of the image panel 23a
1a and the glass substrate 12a of the phase compensation panel 23b, an antireflection film is formed, or the glass substrates 11a, 12a
It is preferable to bond them with an adhesive or the like having a refractive index equivalent to. The reason is that the refractive index of air is 1.0 and the refractive index of the glass substrate is a little over 1.5, so that light is reflected due to the difference in refractive index.

Next, the operation of the two-layer liquid crystal display device of this embodiment will be described. The incident light is linearly polarized by the polarizing plate 13a of the image panel 23a and propagates in the liquid crystal layer 14. When no voltage is applied to the liquid crystal layer 14, the polarization plane of the light is rotated by about 90 ° in the liquid crystal layer 14, but the output light from the liquid crystal layer 14 is elliptically polarized light depending on the wavelength because of the wavelength dependence of the propagation characteristics. Become. Since the liquid crystal layer 15 of the phase compensation panel has a reverse twist structure with the liquid crystal molecules of the liquid crystal layer 14 of the image panel 23a, the polarization plane is rotated in the opposite direction by about 90 °,
The wavelength dependence generated in the image panel 23a is compensated. Therefore, the liquid crystal layer 15 of the phase compensation panel 23b
The emitted light from is a linearly polarized light in the same state as the incident light to the liquid crystal layer 14, and the polarization axis of the polarizing plate 13b is arranged in a direction to block this linearly polarized light, so that a good black display is realized. it can.

On the other hand, when a sufficiently high voltage is applied to the liquid crystal layer 14, the liquid crystal molecules in this layer are vertically aligned between the pixel electrode 16 and the counter electrode 22, so that the polarization state of the liquid crystal device 14 does not change. The incident light, on the other hand, has its polarization plane rotated by about 90 ° in the liquid crystal layer 15 and passes through the polarizing plate 13b.

When static electricity is applied from the outside during such an operation, if the electrodes 18a and 18b are short-circuited, the electrodes 18a and 18b holding the liquid crystal device 15 have the same potential, and the liquid crystal It is possible to prevent the alignment disorder from occurring in the layer 15. Further, when the electrodes 18a and 18b are grounded, it is possible to completely prevent the alignment disorder.

Further, by applying an AC signal to the liquid crystal layer 15 via the above-mentioned electrode terminals, it becomes possible to compensate the wavelength dependence of the image panel 23a. Especially when the two-layer liquid crystal display device is used for a liquid crystal projection television,
The wavelengths of light modulation in each liquid crystal display device are different, such as blue, green, and red. Therefore, wavelength dependent compensation may be required. In theory, there should be no problem with such compensation of wavelength dependence if the phases of the liquid crystal layer 15 and the liquid crystal layer 14 are completely in phase. However, as described above, in reality, it is difficult to perfectly match the phases.Therefore, the control of applying an AC signal for compensating the wavelength dependence as in the present embodiment is extremely effective. Adjusting the phase difference often results in better image quality.

Another embodiment of the two-layer liquid crystal display device of the present invention will be described below. Note that, also in other embodiments described below, a configuration in which two electrodes sandwiching a liquid crystal layer of a phase compensation panel are electrically connected, a configuration in which a predetermined potential is applied,
The configuration for applying an AC signal to adjust the phase, the configuration for forming an antireflection film between the image panel and the phase compensation panel, or the configuration for laminating both panels have the same configuration as the above-mentioned embodiment, and therefore the description thereof is omitted. Omit it.

FIG. 6A is a sectional view showing another embodiment of the two-layer type liquid crystal display device. Since the image panel in the figure has the same configuration as that of the above-described embodiment, the diagram and description thereof are omitted, and the configuration of the phase compensation panel will be described.

In the figure, 61 and 62 are transparent electrodes. Specifically, thin films (first thin film and second thin film) on both sides of the transparent electrode ITO (first transparent conductive thin film)
To form an antireflection film structure.
The electrode thus formed in three layers is hereinafter referred to as a three-layer antireflection electrode. The transparent electrodes 61 and 62 shown in the figure correspond to the electrodes 18a and 18b shown in FIG. 1, but since the antireflection structure is adopted, the opening 21 as shown in FIG. 2 is formed. Absent.

Reference numerals 61b and 62b denote ITO films which serve as electrodes. The film thickness of the ITO film is such that the optical film thickness is λ / 2. For example, the peak wavelength λ of incident light is 550
If the thickness is nm, the film thickness d is around 1375Å. The thickness of the ITO film is formed corresponding to λ. 61a,
62a and 61c, 62c are glass substrates 12a, 12
The thin films 61a, 62a and 61c, 62c are made of the same material and have the same film thickness, which are made of a material having a refractive index between the refractive index of b and the refractive index of the ITO films 61b, 62b. Preferably. The optical thickness d of the thin film is given by nd = λ / 4. Note that n is a refractive index.

Further, the thin films 61a, 62a, 61c, 62
Examples of materials for c include aluminum oxide (Al ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), and silicon monoxide (Si).
O), magnesium oxide (MgO), tungsten oxide (WO ₃ ), cerium fluoride (CeF ₃ ), lead fluoride (PbF)
₂ ) is exemplified. Among them, Al ₂ O ₃ , Y ₂ O ₃ , CeF ₃
Is preferable from the standpoints of stability of the substance, light transmission, uniformity of the film, and the like. Further, SiO (n = 1.7) can make the reflectance extremely small in a wide visible light range.

Assuming that the peak wavelength λ of light is 550 nm,
Al ₂ O is formed on the thin films 61a, 62a, 61c and 62c.
_{When 3} (n = 1.63) is used, the film thickness formed is d = 7
In the range of 00Å to 1000Å, ITO film (n≈2.0) 6
The film thicknesses of 1b and 62b may be in the range of 1150Å to 1600Å. If the ITO films 61b and 62b are 1000 Å or more, a necessary and sufficient resistance value can be obtained by forming them by vapor deposition or sputtering at 200 degrees or more. The thin films 61a, 62a, 61c, and 62c are made of Y ₂ O ₃ (n = 1.7).
In the case of 8), d = 650Å to 900Å may be set.

As a result of examining the above conditions, when the refractive index n of the ITO film is about 2.0, the thin films 61a and 62a are formed.
When Y ₂ O ₃ is used as a, 61c, and 62c, the reflectance can be made extremely small over almost the entire visible light range, and when the refractive index n of the ITO film is smaller than 1.9,
When Al ₂ O ₃ is used as the thin films 61a, 62a, 61c and 62c, the reflectance can be made extremely small in the visible light range.

As described above, the three-layer antireflection electrodes 61, 6
By forming 2, the reflectance of light can be significantly reduced, and when the band of modulated light is relatively narrow, the reflectance can be 0.1% or less at the peak wavelength.
As a matter of course, when the AC signal is applied between the transparent electrodes 61 and 62, the voltage is applied.

In FIG. 6 (a), the transparent electrodes 61 and 62 are connected to three electrodes.
Although the antireflection film having a layered structure is used, an antireflection film having a two-layered structure may be used. Hereinafter, the antireflection electrode having the two-layer structure will be described with reference to FIG.

In FIG. 6B, the antireflection electrode having a two-layer structure has thin films (third thin films) 63a and 64a formed on glass substrates 12a and 12b, and an ITO film (second thin film) formed thereon. Transparent conductive thin films) 63b and 64b are formed, and the ITO films 63b and 64b are made to have an optical film thickness of λ / 2. For example, when λ is 550 nm, it is around d = 1375Å. The ITO film and the film thickness are formed corresponding to the peak wavelength λ of the incident light. In addition, the refractive index of the thin film is preferably 1.50 or more and 1.70 or less, and it is preferable to use a substance having a refractive index between that of the glass substrate and that of the liquid crystal layer 15. From this point of view, the refractive indexes of the thin films 63a and 64a are 1.52 or more.
It is preferably 65 or less. Materials having a refractive index in this range include aluminum oxide Al ₂ O ₃ (n≈1.63), silicon monoxide SiO (n≈1.65), and cerium fluoride C _e.
F ₃ (n≈1.63), lanthanum fluoride LaF ₃ (n≈1.
55) and neodymium fluoride NdF ₃ (n≈1.55). Tungsten oxide WO ₃ (n≈
1.68) can also be used.

When λ is 550 nm, the thin films 63a, 6a
When Al ₂ O ₃ (n≈1.63) is used for 4a, the film thickness formed is in the range of d = 700Å to 1000Å, and the ITO film (n
The film thickness of ≈2.0) may be in the range of 1150Å to 1600Å. If the ITO film has a thickness of 1000 Å or more, a necessary and sufficient resistance value can be obtained by forming it by vapor deposition or sputtering at 200 ° or more.

In order to obtain a simpler antireflection structure, the thin films 63a and 64b in FIG. 6B are removed. That is, the ITO film is formed on the glass substrates 12a and 12b so that the optical film thickness is λ / 2. In this case, a good low reflectance cannot be realized when the incident light band is wide, but a practically sufficient reflectance is obtained when the light band that each liquid crystal display device is responsible for is narrow as in a liquid crystal projection television. Can be realized.

There is an equivalent film forming technique shown in FIGS. 7A and 7B as a method of forming a transparent electrode having an optimum low reflectance. Although the equivalent film has a structure of four or more thin films and the cost increases, an extremely good antireflection film can be realized.

FIG. 7 shows the glass substrate 11a of the image panel.
And a configuration for optically coupling both glass substrates 12a of the phase compensation panel and the air by using a transparent coupling member as a method for preventing reflection at the interface between the two glass substrates. (A) shows the liquid crystal display device in the holder 6
7 is a plan view showing a state of being incorporated in FIG. 7, (b) of FIG.
Is a sectional view thereof.

In both figures, the image panel is a holder 67.
And is fixed by a fastener 66a. on the other hand,
The phase compensating panel is installed on an annular fastener 66b and fixed by the fastener 66c.
It is arranged so as to be rotatable in a state where it is inserted in 7. In addition, 66d is a fastener for preventing falling. 6
Reference numeral 5 is an optical coupling agent as a transparent bonded body, and specific examples thereof include liquids such as ethylene glycol and gel silicone resins. By filling the optical coupling agent 65, the glass substrates 11a and 12
a is optically coupled to eliminate reflected light and improve the transmittance. Also, halation in the glass substrates 11a and 12a is reduced. 11b is a counter substrate of the image panel,
12b is a counter substrate of the phase compensation panel.

Since the fastener 66c is configured to be rotatable in the holder 67, the angle of the polarization axis between the polarizing plate on the image panel side (not shown) and the polarizing plate on the phase compensation panel side (not shown) can be changed. It is configured to be possible. This is intended to compensate the phase difference between both panels by adjusting the polarization axis angle in order to completely compensate.

Next, a liquid crystal projection type television using the two-layer type liquid crystal display device of the present invention will be described. The configuration of the liquid crystal projection type television can be realized by replacing the liquid crystal display devices 90a, 90b, 90c of the conventional liquid crystal projection type television shown in FIG. 9 with the two-layer type liquid crystal display device of this embodiment. As a result, it is possible to realize good black display without disturbing the alignment. Further, although three two-layer liquid crystal display devices are used in FIG. 9, the liquid crystal projection television of the present embodiment is not limited to this.
It may be used only for one optical path (one of R, G, and B). The reason is that the liquid crystal display device has a property that a good contrast cannot be obtained especially when performing modulation of blue light. Therefore, for the purpose of improving it, the liquid crystal of this embodiment is used only in the optical path of the blue light. This is because the image quality can be improved even if the display device is arranged.

Further, the liquid crystal projection type television shown in FIG. 9 is an example of a constitution using three two-layer liquid crystal display devices, but color display can be performed even with one two-layer liquid crystal display device of this embodiment. it can. Specifically, a color filter may be attached to the image panel of the two-layer liquid crystal display device to enlarge and project the image. In this case, the color separation optical system is unnecessary and the device can be downsized.

On the other hand, there is also a method of arranging a color separation / color synthesis optical system and using one projection lens to obtain a color display. FIG. 5 shows the configuration of the liquid crystal projection television. In the figure, 58a, 58b and 58c are phase compensation panels, and 57a, 57b and 57c are image panels.
In the figure, the image panel is arranged on the light incident side and the phase compensation panel is arranged on the light emitting side, but this relationship may be reversed.

The configuration will be described in detail below. In FIG. 5, reference numeral 51 denotes a metal halide lamp which is a light emitting source, and 52
Is an ultraviolet and infrared cut mirror (hereinafter referred to as UVIR cut mirror), 53 is a screen, 54 is a projection lens, 55a and 55b are total reflection mirrors, and 56a and 56
b, 56c and 56d are mirrors (hereinafter referred to as dichroic mirrors) having a function of reflecting or transmitting light having a wavelength in a specific region of the emitted light of the metal halide lamp 51, 57a, 57b and 57c are image panels, 58a,
Reference numerals 58b and 58c are phase compensation panels.

Here, for simplification of description, the image panel 57b is a panel (symbol G) for displaying a green image among the images displayed on the screen 53, and the image panel 57a.
Is a panel for displaying a red image (symbol R), and the image panel 57c is a panel for displaying a blue image (symbol B). Therefore, each dichroic mirror 56a, 56
As for the wavelengths that transmit and reflect b, the dichroic mirror 56a reflects light having a wavelength in the red region (hereinafter referred to as R light), and has light in the green region (hereinafter referred to as G light) and a wavelength in the blue region (hereinafter referred to as G light). Hereinafter, it will be referred to as B light). The dichroic mirror 56b reflects G light and transmits B light. Also, the dichroic mirror 5
For 6d, G light, R light, and B light are to be combined.

Next, the operation of the above liquid crystal projection television will be described. The light emitted from the metal halide lamp 51 is cut by the UVIR cut mirror 52 in the wavelength regions of the ultraviolet region and the infrared region. The light from which the ultraviolet rays and the infrared rays have been cut is separated into three wavelength regions of R light, G light, and B light by the dichroic mirrors 56a and 56b, and the R light is image panel 57.
a, G light to the image panel 57b, and B light to the image panel 5
7c respectively. Next, each liquid crystal panel rotates the light by changing the orientation of each liquid crystal,
Modulates light. R light and G modulated in this way
An image obtained by combining the light and the B light by the dichroic mirrors 56c and 56d is projected on the screen 53 by the projection lens 54.

As described above, in the two-layer liquid crystal display device of the present invention, in order to solve the conventional problems, the transparent electrode is formed on the surface side of the phase compensation panel in the two-layer liquid crystal display device which is in contact with the liquid crystal layer. Then, an alignment film is formed on the electrode to align the liquid crystal in the liquid crystal layer.

Further, in order to reduce the reflectance of light, the above-mentioned transparent electrode is formed with an opening part of which is removed, or a thin film having a predetermined optical thickness is formed on both sides of the transparent electrode. It is formed as an antireflection film. Then, it is preferable that one end of the transparent electrode is drawn out of the panel and fixed or an AC signal can be applied to the external electrode so that the alignment state of the liquid crystal layer can be controlled.

The projection type display device of the present invention comprises the two-layer liquid crystal display device of the present invention.
Attaching a color filter to two 2-layer liquid crystal display devices,
A television that magnifies and projects the image of the two-layer liquid crystal display device,
Alternatively, the light emitted from one light source is divided into three primary colors of red, green, and blue by using a dichroic mirror, guided to three two-layer liquid crystal display devices, modulated, and then combined on a screen for color display. It can be used for display devices.

Further, the two-layer type liquid crystal display device of the present invention is not limited to the display device as described above, and any device having a structure for projecting an image through the liquid crystal panel can be applied.

[0057]

As is apparent from the above description,
According to the present invention of claim 1, since a transparent electrode is formed on the phase compensation panel, an alignment film is formed on the transparent electrode, and the transparent electrode is fixed at a predetermined potential, alignment disturbance due to static electricity or the like occurs. do not do. Therefore, there is an advantage that an image display with good uniformity can be performed without displaying a blank image.

According to the third aspect of the present invention, since the transparent electrode has the antireflection structure or the opening is formed, the light transmittance is not reduced and the occurrence of halation is prevented. It has the advantage of being able to.

Further, in the present invention of claim 4, since the phase compensating panel and the liquid crystal panel are optically coupled, there is an advantage that the loss of incident light can be prevented.

According to the twelfth aspect of the present invention, the amount of phase compensation can be varied by applying an AC signal to the phase compensation panel and varying the alignment state of the liquid crystal layer, so that there is no phase difference with the image panel. And has an advantage that good black display can be performed.

According to the thirteenth aspect of the present invention, since the two-layer liquid crystal display device of the present invention is used in the portion that modulates the light emitted from the light source, the alignment disorder does not occur, and the projection The displayed image can be displayed in good black, and good contrast can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing a configuration of a two-layer liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a partial plan view showing the electrode structure shown in FIG.

FIG. 3 is an enlarged cross-sectional view of an essential part showing the electrode structure shown in FIG.

FIG. 4 is a perspective view showing connection points of the electrodes shown in FIG.

FIG. 5 is a perspective view showing a configuration of a projection display device according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of essential parts showing another embodiment of the two-layer liquid crystal display device of the present invention.

FIG. 7 is an explanatory view showing still another embodiment of the two-layer type liquid crystal display device of the present invention.

FIG. 8 is a configuration diagram of a conventional two-layer liquid crystal display device.

FIG. 9 is an explanatory diagram showing a configuration of a conventional liquid crystal projection television.

[Explanation of symbols]

 11a, 11b, 12a, 12b Glass substrate 13a, 13b Polarizing plate 14,15 Liquid crystal layer 16 Pixel electrode 17 Black matrix 18a, 18b Electrode 19,20 Alignment film 21 Opening part 22 Counter electrode 23a Image panel (first) 23b Phase compensation panel (second panel) 31 Conductor 51 Metal halide lamp 52 UVIR cut mirror 53 Screen 54 Projection lens 55a, 55b Total reflection mirror 56a, 56b, 56c, 56d Dichroic mirror 57a, 57b, 57c Image panel 58a , 58b, 58c Phase compensation panel 61, 62, 63, 64 Transparent electrode 65 Optical coupling agent (transparent combination)

Claims (16)

[Claims] 1. A first liquid crystal panel for performing light modulation, and a substrate, a liquid crystal layer, and a liquid crystal layer sandwiched between the first liquid crystal panel and a substrate for compensating for a phase difference generated during the light modulation in the first liquid crystal panel. A two-layer liquid crystal display device, comprising: 2. A first liquid crystal panel and a second liquid crystal panel, which are arranged close to each other so that twists of twisted nematic liquid crystal molecules are opposite to each other, and incident light is incident on a liquid crystal layer of the first liquid crystal panel. The first liquid crystal panel is configured so as to be emitted through the liquid crystal layer of the second liquid crystal panel, and the first liquid crystal panel has a pixel electrode formed thereon, and the first liquid crystal panel is formed by a signal applied to the pixel electrode. The liquid crystal alignment state of the liquid crystal layer can be varied, and the second liquid crystal panel has an alignment film on a surface facing the liquid crystal layer, and a transparent conductive thin film is formed on each alignment film. A characteristic two-layer liquid crystal display device. 3. The two-layer liquid crystal display device according to claim 2, wherein the transparent conductive thin film has an incident light reflection preventing function or has an opening provided in a region facing the pixel electrode. 4. The two-layer liquid crystal display device according to claim 1, wherein the first liquid crystal panel and the second liquid crystal panel are optically coupled by a transparent coupling body. 5. The transparent conductive thin film of the second liquid crystal panel is electrically connected to each other.
Or a two-layer liquid crystal display device according to item 2. 6. The two-layer liquid crystal display device according to claim 1, wherein the potential of the transparent conductive thin film can be fixed to a predetermined potential. 7. The transparent conductive thin film is formed by sequentially stacking a first thin film, a first transparent conductive thin film, and a second thin film, and a refractive index of the first thin film and the second thin film. Is the refractive index between the refractive index of the substrate of the second liquid crystal panel and the refractive index of the first transparent conductive thin film, and the optical film thickness of the first and second thin films is approximately λ. 3. / 4 (λ is the peak wavelength of light incident on the liquid crystal panel), and the optical film thickness of the first transparent conductive thin film is approximately λ / 2. Layer type liquid crystal display device. 8. The transparent conductive thin film is formed by sequentially stacking a third thin film and a second transparent conductive thin film, and the refractive index of the third thin film is 1.50 or more and 1.70 or less. The optical thickness of the third thin film is approximately λ / 4 (λ is the peak wavelength of light incident on the liquid crystal panel), and the optical thickness of the second transparent conductive thin film is approximately λ /. The two-layer liquid crystal display device according to claim 2, wherein the two-layer liquid crystal display device is 2. 9. The first and second thin films are made of any one of aluminum oxide, yttrium oxide, silicon monoxide, magnesium oxide, tungsten oxide, cerium fluoride and lead fluoride. Item 2. A two-layer liquid crystal display device according to item 7. 10. The third thin film according to claim 8, wherein any one of aluminum oxide, silicon monoxide, tungsten oxide, cerium fluoride, lanthanum fluoride, and neodymium fluoride is used for the third thin film. Layer type liquid crystal display device. 11. The two-layer liquid crystal display device according to claim 4, wherein the positional relationship between the first liquid crystal panel and the second liquid crystal panel can be varied. 12. A two-layer liquid crystal display device according to claim 2, wherein an AC signal can be applied to the transparent conductive thin film of the second liquid crystal panel, and the alignment state of liquid crystal molecules can be changed. . 13. A two-layer liquid crystal display device according to claim 1, wherein one light source and light emitted from the light source are modulated, and the light modulated by the two-layer liquid crystal display device is enlarged and projected. A projection display device comprising a projection lens for 14. A light source, a color separation optical system section for separating emitted light from the light source into a plurality of colors, and at least one optical path of the light paths of the light separated by the color separation optical system section. A two-layer type liquid crystal display device according to claim 1 or 2, and a projection lens for magnifying and projecting light modulated by the two-layer type liquid crystal display device. . 15. The projection display apparatus according to claim 14, wherein the color separation optical system section separates into three primary colors of red, green and blue. 16. An optical image of a liquid crystal display device that modulates blue light, an optical image of a liquid crystal display device that modulates red light, and an optical image of a liquid crystal display layer that modulates green light are superimposed on the same position on the screen. The image is projected as follows.
4. The projection display device according to item 4.