JP2005300735A - Liquid crystal device and electronic appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal device which certainly prevents alignment disorder of a liquid crystal in the vicinity of a sealing material without reducing productivity. <P>SOLUTION: In the liquid crystal device 100, a pair of substrates 10, 20 are stuck on each other with the sealing material 52 disposed in a frame like shape and a display region is arranged inside the region formed with the sealing material 52. Vertical alignment layers 11, 21 are disposed on the inside of both of the pair of substrates 10, 20 wherein the vertical alignment layers 11, 21 have first vertical alignment layers 11a, 21a disposed on the display region and composed of an inorganic material and second alignment layers 11b, 21b disposed between the display region and the sealing material 52 and composed of an organic material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a configuration of a liquid crystal device and an electronic apparatus, particularly a vertical alignment mode liquid crystal device.

In general, in a liquid crystal device used as a light valve of a liquid crystal projector or a display such as a mobile phone, an alignment film for controlling the alignment of liquid crystal molecules is formed on the outermost surface of a substrate sandwiching the liquid crystal layer. As this alignment film, a film obtained by rubbing an organic film such as polyimide is widely used. However, such an organic alignment film is excellent in alignment force, but is weak against heat and light, and there is a problem that the alignment force gradually decreases with long-term use. For example, when mounted on a projector that is irradiated with high-intensity light with a light flux density of about ² to 10 (lm / mm ² ), the alignment film is gradually decomposed by light and heat from the light source, and the liquid crystal molecules are In some cases, it may become impossible to arrange at a desired pretilt angle.

Therefore, in order to solve such a problem, a technique has been proposed in which the alignment film is composed of an inorganic film, and the liquid crystal is aligned by the shape effect of the inorganic film. Such an inorganic alignment film is superior in light resistance and solvent resistance as compared to an organic alignment film such as polyimide, and has high alignment stability. On the other hand, however, the inorganic alignment film has an alignment regulating power that is one digit or more smaller than that of an organic alignment film that is aligned by rubbing or the like. It is easy to receive and it is easy to generate orientation failure. For example, in the outer periphery of the display area, the alignment is easily disturbed by impurities (volatile components, etc.) eluted from the sealing material, and particularly in a projector, the liquid crystal is in a high temperature state, and thus such alignment disorder becomes significant. As a countermeasure, Patent Document 1 proposes a method of removing a volatile component in the sealing material by performing a heat treatment after the sealing material is cured with ultraviolet rays.
JP 7-168292 A

  However, in practice, it is difficult to completely remove volatile components even if the above-described method is used. Moreover, even if the volatile components can be sufficiently removed by the heat treatment for a long time, problems remain in terms of productivity. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid crystal device capable of reliably preventing alignment disorder of liquid crystal in the vicinity of a sealing material without impairing productivity.

  In order to solve the above problems, a liquid crystal device according to the present invention is a liquid crystal device in which a liquid crystal is sandwiched between a pair of substrates, and the pair of substrates are bonded together by a sealing material provided in a frame shape, A display region is provided inside the region where the sealing material is formed, a vertical alignment film is provided inside both the pair of substrates, and the vertical alignment film is an inorganic layer provided in the display region. A first vertical alignment film made of a material, and a second vertical alignment film made of an organic material provided between the display region and the sealing material.

  In general, an organic film such as polyimide has a property of easily adsorbing impurities as compared with an inorganic film. This is because the organic film has a complicated side chain structure, and each side chain functions as an impurity adsorption site by its electrical action. In the liquid crystal device of the present invention, an organic alignment film (second vertical alignment film) is disposed between the sealing material and the display region, so that this functions as a kind of adsorption layer and diffusion of impurities into the display region. Can be prevented. In addition, since the organic alignment film is superior in alignment force to the inorganic alignment film, the alignment is not greatly disturbed even if impurities are adsorbed. Further, in the liquid crystal device of the present invention, since the display area is controlled by the inorganic alignment film (first vertical alignment film), the light resistance and resistance to light are higher than when the vertical alignment film is composed only of the organic alignment film. It is excellent in solvent property, and the orientation is controlled by the shape effect, so that stable orientation can be obtained. As described above, in the liquid crystal device of the present invention, it is possible to reliably prevent the alignment disorder of the liquid crystal in the vicinity of the sealing material without performing a heat treatment for a long time.

In the liquid crystal device of the present invention, it may be provided in a frame shape along the outer periphery of the display area. Thus, by disposing the organic alignment film so as to surround the periphery of the display region, it is possible to reliably prevent the diffusion of impurities into the display region.
In the liquid crystal device of the present invention, the second vertical alignment film may be disposed close to or adjacent to the sealing material. By doing so, the effect of adsorbing impurities can be enhanced.

  In the liquid crystal device of the present invention, it is assumed that the second vertical alignment film provided on the inner side of both of the pair of substrates is disposed so as to have a region overlapping each other in a plane. be able to. By doing so, it is possible to reliably block the diffusion of impurities at the position where both alignment films face each other. Therefore, according to this configuration, the alignment force of the liquid crystal molecules can be increased in the region where the second vertical alignment films overlap, and the impurity adsorption effect can be further increased.

  In the liquid crystal device of the present invention, a liquid crystal injection port for injecting the liquid crystal is provided in a part of the frame of the sealing material provided in a frame shape, and the liquid crystal injection port is sealed with a sealing material. The second vertical alignment film may be disposed between the sealing material and the display region. By doing so, impurities eluted from the sealing material can also be adsorbed.

  An electronic apparatus according to the present invention includes the above-described liquid crystal device. Thereby, an electronic device with high display quality and excellent reliability can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size. In the present specification, the liquid crystal layer side of each component of the liquid crystal device is referred to as an inner side, and the opposite side is referred to as an outer side.

  FIG. 1 is an equivalent circuit of an active matrix liquid crystal device which is an example of the liquid crystal device of the present invention. In the liquid crystal device of this embodiment, pixel electrodes 9 are formed on a plurality of dots arranged in a matrix to form a display area. Further, on the side of the pixel electrode 9, a TFT element 30 that is a switching element for performing energization control to the pixel electrode 9 is formed. A data line 6 a is electrically connected to the source of the TFT element 30. Image signals S1, S2,..., Sn are supplied to each data line 6a. The image signals S1, S2,..., Sn may be supplied to each data line 6a in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. .

  The scanning line 3 a is electrically connected to the gate of the TFT element 30. Scan signals G1, G2,..., Gm are supplied to the scanning line 3a in pulses at a predetermined timing. The scanning signals G1, G2,..., Gm are applied sequentially to each scanning line 3a in this order. Further, the pixel electrode 9 is electrically connected to the drain of the TFT element 30. When the TFT element 30 serving as a switching element is turned on for a certain period by the scanning signals G1, G2,..., Gm supplied from the scanning line 3a, the image signals S1, S2,. , Sn are written into the liquid crystal of each pixel at a predetermined timing.

  The predetermined level image signals S1, S2,..., Sn written in the liquid crystal are held for a certain period by a liquid crystal capacitor formed between the pixel electrode 9 and a common electrode described later. In order to prevent the retained image signals S1, S2,..., Sn from leaking, a storage capacitor 29 is formed between the pixel electrode 9 and the capacitor line 3b, and is arranged in parallel with the liquid crystal capacitor. . Thus, when a voltage signal is applied to the liquid crystal, the alignment state of the liquid crystal molecules changes depending on the applied voltage level. As a result, the light incident on the liquid crystal is modulated to enable gradation display.

  Next, the overall configuration of the liquid crystal device will be described with reference to FIG. 2A is a plan view of the TFT array substrate as viewed from the side of the counter substrate together with the components formed thereon, and FIG. 2B is a diagram showing the counter substrate including the counter substrate. It is sectional drawing in alignment with line HH '.

  In the liquid crystal device 100 according to the present embodiment, the TFT array substrate 10 (active matrix substrate) and the counter substrate 20 are bonded to each other by a sealing material 52 provided in a rectangular frame shape, and in the region partitioned by the sealing material 52. A liquid crystal layer 50 is enclosed in the liquid crystal layer 50. A light-shielding film (peripheral parting) 53 made of a light-shielding material is formed in a region inside the region where the sealing material 52 is formed, and a region inside the region where the light-shielding film 53 is formed becomes a display region. In the peripheral circuit area outside the sealing material 52, a data line driving circuit 201 and an external circuit mounting terminal 202 are formed along one side of the TFT array substrate 10, and scanning lines are formed along two sides adjacent to the one side. A drive circuit 104 is formed. On the remaining side of the TFT array substrate 10, a plurality of wirings 105 are provided for connecting between the scanning line driving circuits 104 provided on both sides of the display area. In addition, an inter-substrate conductive material 106 for providing electrical continuity between the TFT array substrate 10 and the counter substrate 20 is disposed at a corner portion of the counter substrate 20. In FIG. 2A, reference numeral 52 a is a liquid crystal injection port formed in the sealing material 52, and reference numeral 55 is a sealing material for sealing the liquid crystal injection port 52.

In FIG. 2B, a vertical alignment film 11 is formed on the outermost surface of the TFT array substrate 10. The vertical alignment film 11 includes a first vertical alignment film 11a provided in the display area, and a second vertical alignment film 11b provided in a rectangular frame shape along the outer periphery of the display area. .
The first vertical alignment film 11a is made of an inorganic alignment film having a predetermined surface shape capable of aligning liquid crystals. As the inorganic alignment film 11a, but it may be a known, in this embodiment, for example this SiO ₂ oblique deposition film. The second vertical alignment film 11b is made of an organic alignment film such as polyimide or polyamide. Unlike the inorganic alignment film 11a described above, the organic alignment film 11b can firmly regulate the alignment state of the liquid crystal by the intermolecular force between the liquid crystal and the organic alignment film 11b. For this reason, even if impurities are eluted from the sealing material 52 in the vicinity of the organic alignment film, the alignment of the liquid crystal in the vicinity of the alignment film is hardly disturbed. In addition, since the above-described materials such as polyimide have a property of easily adsorbing impurities, by disposing such an organic alignment film 11b in the vicinity of the sealing material, the organic alignment film 11b functions as an impurity adsorption layer, and is displayed. Diffusion of impurities to the region side can be prevented.

  On the other hand, a vertical alignment film 21 made of the same material is also provided on the outermost surface of the counter substrate 20. That is, the vertical alignment film 21 includes a first vertical alignment film 21a made of an inorganic alignment film provided in the display area and a second alignment film made of an organic alignment film provided in a rectangular frame shape along the outer periphery of the display area. Vertical alignment film 21b. The organic alignment film 21b and the organic alignment film 11b have the same shape and are formed at positions facing each other.

Next, a method for manufacturing the liquid crystal device 100 of the present embodiment will be described.
First, the TFT array substrate 10 and the counter substrate 20 are manufactured using a known method, and the inorganic alignment films 11a and 21a are formed on the surfaces of these substrates by oblique vapor deposition. In this case, the deposition angle is, for example, an angle that forms 55 ° from the substrate normal, and the thickness is 40 nm.
Next, organic alignment films 11b and 21b made of, for example, Optomer AL00010 (manufactured by JSR) are formed on the surfaces of these inorganic alignment films as the above-described materials. At this time, the organic alignment films 11b and 21b are formed in a rectangular frame shape along the sealing material 52 so as to surround the display area. In particular, it is desirable to form it at a position close to or adjacent to the sealing material 52. In this example, the outer peripheral portions of the organic alignment films 11b and 21b are brought close to each other to the extent that the sealing material 52 is formed. Further, since impurities may be eluted from the sealing material 55, the organic alignment films 11b and 21b are also formed between the sealing material 55 and the display region (that is, the position where the liquid crystal injection port 52a is formed). To do. In addition, flexographic printing etc. can be used suitably as a formation method of the organic orientation films 11b and 21b.

  Next, a sealing material 52 is applied to one of the substrates 10 and 20. The sealing material 52 may be either an ultraviolet curable type (acrylic resin) or a thermosetting type (epoxy resin), or a mixture thereof. In this example, the sealing material 52 is an ultraviolet curing type, and this is disposed in a rectangular frame shape on the substrate by a dispenser. At this time, an opening (liquid crystal injection port 52a) is provided in a part of the frame. The sealing material 52 is mixed with a spacer for defining the cell thickness.

Next, the two substrates 10 and 20 are bonded together by the sealing material 52, and the sealing material 52 is cured by irradiating with 3000 mJ of ultraviolet rays. At this time, heat treatment is performed as necessary to cure the uncured component in the sealing material. The heat treatment is performed, for example, by heating in an oven at 120 ° C. for 1 hour. When the empty cell is manufactured as described above, this time, liquid crystal having negative dielectric anisotropy is injected into the empty cell through the liquid crystal injection port 52a provided in the sealing material 52.
Thus, the liquid crystal device 100 is manufactured.

  As described above, in this embodiment, since the organic alignment films 11b and 21b are disposed between the sealing material 52 and the display region, this functions as an impurity adsorption layer, and the diffusion of the impurity into the display region is prevented. Can be prevented. In addition, since the organic alignment films 11b and 21b are superior in alignment force to the inorganic alignment films 11a and 21a, the alignment is not greatly disturbed even if impurities are adsorbed. In this embodiment, since the display area is controlled by the inorganic alignment films 11a and 21a, light resistance and solvent resistance can be obtained as compared with the case where the vertical alignment films 11 and 21 are composed of only the organic alignment films 11b and 21b. In addition, since the orientation is controlled by the shape effect, a stable orientation can be obtained.

In the present embodiment, the organic alignment films 11b and 21b are arranged adjacent to the sealing material 52, but the arrangement of the organic alignment films 11b and 21b is not limited to this. 3 and 4 are diagrams showing other arrangement examples. FIG. 3 shows an example in which the organic alignment films 11b and 21b are arranged so as to include the formation region of the sealing material 52. FIG. 4 shows the organic alignment films 11b and 21. Each of the examples is arranged separately from the sealing material 52. 3 (a) and 4 (a) are plan views corresponding to FIG. 2 (a), schematically showing only the arrangement relationship between the sealing material and the organic alignment film. FIGS. 4B and 4B are schematic cross-sectional views corresponding to FIG.
In these configurations, the same effect as described above can be obtained. However, in the example of FIG. 3, the adhesion between the substrate and the sealing material is reduced by the amount of the sealing material disposed on the organic alignment film, but the impurity adsorption effect is the other two examples shown in FIGS. 2 and 4. Compared to the above configuration. Further, in the example of FIG. 4, since the organic alignment film is separated from the sealing material, the effect of adsorbing impurities is smaller than that of the other two examples shown in FIGS. Since the alignment film is not disposed, the adhesion between the substrate and the sealing material is higher than in the other two examples.

[Electronics]
Next, a projection-type liquid crystal display device (liquid crystal projector) will be described as an example of an electronic apparatus using the above-described liquid crystal device.
FIG. 5 is a diagram showing a schematic configuration of the liquid crystal projector. As shown in this figure, a lamp unit 1102 including a white light source such as a halogen lamp is provided inside the projector 1100. The projection light emitted from the lamp unit 1102 is separated into three primary colors of red (R), green (G), and blue (B) by three mirrors 1106 and two dichroic mirrors 1108 arranged inside. Are guided to the light valves 100R, 100G and 100B corresponding to the respective primary colors.

  Here, the configuration of the light valves 100R, 100G, and 100B is the same as that of the liquid crystal device according to the above-described embodiment, and R, G, and B primary colors supplied from a processing circuit (not shown) that inputs an image signal. Each is driven by a signal. In addition, B light has a long optical path compared to other R colors and G colors, and therefore, in order to prevent the loss, B light passes through a relay lens system 1121 including an incident lens 1122, a relay lens 1123, and an exit lens 1124. Led.

The lights modulated by the light valves 100R, 100G, and 100B are incident on the dichroic prism 1112 from three directions. In the dichroic prism 1112, R and B light is refracted by 90 degrees, while G light travels straight.
In this manner, after the images of the respective colors are combined, a color image is projected onto the screen 1120 by the projection lens 1114.
Since the projection type display device of this embodiment includes the liquid crystal device of the above embodiment, the display device has high display quality and excellent reliability.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. For example, the liquid crystal device according to the embodiment is not limited to the projection display device described above, and can be mounted on various electronic devices. Examples of such electronic devices include mobile phones, electronic books, personal computers, digital still cameras, liquid crystal televisions, viewfinder type or monitor direct view type video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations. There are devices such as videophones, POS terminals, touch panels, etc., and the liquid crystal device can be suitably used as these image display means. Further, the shapes and combinations of the constituent members shown in the above-described examples are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

1 is an equivalent circuit diagram of a liquid crystal device according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a schematic configuration of the liquid crystal device. FIG. 6 is a schematic diagram illustrating another configuration example of the liquid crystal device. FIG. 6 is a schematic diagram illustrating another configuration example of the liquid crystal device. FIG. 3 is a schematic diagram illustrating an example of an electronic apparatus including a liquid crystal device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... TFT array substrate, 11, 21 ... Vertical alignment film, 11a, 21a ... Inorganic alignment film (first vertical alignment film), 11b, 21b ... Organic alignment film (second vertical film) Alignment film), 20 ... counter substrate, 50 ... liquid crystal, 52 ... sealing material, 52a ... liquid crystal injection port, 55 ... sealing material, 100 ... liquid crystal device, 1100 ... ·Electronics

Claims (6)

A liquid crystal device having a liquid crystal sandwiched between a pair of substrates,
The pair of substrates are bonded together by a sealing material provided in a frame shape, a display region is provided inside the region where the sealing material is formed, and a vertical alignment film is provided inside both the pair of substrates. The vertical alignment film is a first vertical alignment film made of an inorganic material provided in the display region, and a second material made of an organic material provided between the display region and the sealing material. A liquid crystal device comprising a vertical alignment film.   The liquid crystal device according to claim 1, wherein the second vertical alignment film is provided in a frame shape along an outer peripheral portion of the display region.   The liquid crystal device according to claim 1, wherein the second vertical alignment film is disposed close to or adjacent to the sealing material.   The second vertical alignment film provided on the inner side of both of the pair of substrates is disposed so as to have a region overlapping each other in a plane. The liquid crystal device according to any one of the above items.   A liquid crystal injection port for injecting the liquid crystal is provided in a part of the frame of the sealing material provided in a frame shape, and the liquid crystal injection port is sealed with a sealing material, and the second The liquid crystal device according to claim 1, wherein a vertical alignment film is disposed between the sealing material and the display region. An electronic apparatus comprising the liquid crystal device according to claim 1.

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