JP4915193B2 - Liquid crystal devices and electronic equipment - Google Patents

Description

  The present invention relates to a liquid crystal device suitable for use in displaying various types of information.

  In a conventional liquid crystal device, when light from the outside is irradiated on the display screen, the light is reflected on the display screen, and the observer is difficult to see the display screen by the reflected light reflected on the display screen. There was a problem of becoming. In this case, the reflection light reflected on the display screen can be reduced by performing a process called AR coating (anti-reflective coating) on the display screen of the liquid crystal device and providing an antireflection film ( Patent Document 1).

  In recent years, a liquid crystal device called a horizontal electric field method has been spotlighted. This method is a method in which the direction of the electric field applied to the liquid crystal is substantially parallel to the substrate, and has an advantage that visual characteristics can be improved as compared with a TN (Twisted Nematic) method or the like. As this lateral electric field type liquid crystal device, a liquid crystal device such as an IPS (In-Plane Switching) method or an FFS (Fringe Field Switching) method is known. This horizontal electric field type liquid crystal device has a structure in which liquid crystal is sandwiched between two substrates, and a comb-shaped pixel electrode and a common electrode that generates a horizontal electric field between the pixel electrode, They are provided on the same substrate.

  However, in such a horizontal electric field type liquid crystal device, when a charge is charged on a substrate on which no electrode is provided due to external static electricity or the like, a substrate on which an electrode is provided and a substrate on which no electrode is provided In some cases, an electric field is generated between them, and proper display cannot be performed.

  Patent Document 2 shown below describes a liquid crystal device having a shield function by providing a conductive layer on the surface of a substrate of a liquid crystal display panel and conducting the conductive layer to a metal frame.

JP 2000-52492 A JP 2004-355035 A

  However, as described in Patent Document 1 described above, in order to provide a conductive layer on the substrate surface of the liquid crystal display panel, a complicated process or a large-scale apparatus is required. In addition, when the conductive layer is electrically connected to the metal frame, the device itself is increased in size, which is not preferable from the viewpoint of reducing the thickness of the liquid crystal device.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid crystal device that has an antireflection function and a shielding function and is thinned.

In one aspect of the present invention, a liquid crystal device includes a lateral electric field type liquid crystal display panel in which liquid crystal is sandwiched between two substrates, and an outer surface side substrate of the two substrates of the liquid crystal display panel. An antireflection film that is installed on the side opposite to the liquid crystal side and in which a thin film layer having a high refractive index and a thin film layer having a low refractive index are alternately stacked, and a polarizing plate disposed on the antireflection film are provided. The antireflection film is formed wider than the area of the polarizing plate, and among the thin film layers constituting the antireflection film, at least the outermost thin film layer has conductivity and is electrically connected through the region where the thin film layer is exposed. Grounded .

In the liquid crystal device such as this can reduce the thickness of the device which has both the antireflection function and the shielding function.

Further, an antireflection film, of two substrates, at Rukoto forming shape on the outer surface of the substrate not common electrode and the pixel electrodes are formed, in the liquid crystal display panel of the horizontal electric field mode, such as by a suitable display static Can be prevented.

  In another aspect of the present invention, an electronic device including the above-described liquid crystal device as a display portion can be configured.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the illumination device of the present invention is applied to a liquid crystal device.

[Configuration of liquid crystal device]
FIG. 1 is a cross-sectional view of a liquid crystal device 100 according to the present embodiment. FIG. 2 is a plan view of the liquid crystal device 100 according to the present embodiment. FIG. 1 is a cross-sectional view taken along the broken line AA ′ of the liquid crystal device 100 of FIG.

  The liquid crystal device 100 mainly includes a lighting device 10 and a liquid crystal display panel 20. The illumination device 10 is mainly composed of a light guide plate 11 and a light source unit 15. The liquid crystal display panel 20 is disposed to face the upper surface side of the light guide plate 11. The lighting device 10 includes a reflection sheet 14 on the lower surface side of the light guide plate 11.

  The light source unit 15 is disposed on the end face of the light guide plate 11 and includes a plurality of LEDs 16 that are point light sources. The light L emitted from each LED 16 enters the light guide plate 11 from the end face of the light guide plate 11. In the light guide plate 11, the light L changes its direction by repeating reflection between the upper and lower surfaces of the light guide plate 11 and is emitted toward the liquid crystal display panel 20.

  The liquid crystal display panel 20 has a display area substantially the same as the light emission area of the light guide plate 11. The liquid crystal display panel 20 is configured by bonding substrates 1 and 2 made of glass or the like through a sealing material 3 to form a cell structure and enclosing a liquid crystal 4 therein.

  As shown in FIGS. 1 and 2, a driver IC 21 serving as a liquid crystal driving IC (driver) is directly mounted on the liquid crystal display panel 20 by a COG (Chip On Glass) technique. At the end of the liquid crystal display panel 20, an FPC (Flexible Printed Circuit) 22 which is a flexible substrate is installed. Some terminals of the driver IC 21 are electrically connected to the FPC 22 through wiring 24 formed on the liquid crystal display panel 20.

  A polarizing plate 12 b is installed on the outer surface of the substrate 1. An antireflection film 13 is formed on the outer surface of the substrate 2. A polarizing plate 12 a is installed on the outer surface of the antireflection film 13. The antireflection film 13 has a layer structure and has a function of reducing the brightness of reflected light by canceling out interference by interference when light from the outside is reflected. The antireflection film 13 will be described in detail later.

  For example, a diffusion sheet or a prism sheet is provided as an optical sheet (not shown) between the illumination device 10 and the liquid crystal display panel 20. The diffusion sheet has a role of diffusing the light L emitted from the light guide plate 11 in all directions. The prism sheet has a role of condensing the light L on the liquid crystal display panel 20.

  Here, the liquid crystal display panel 20 will be described. The liquid crystal display panel 20 is a horizontal electric field type liquid crystal display panel. FIG. 3A shows an enlarged cross-sectional view of the liquid crystal display panel 20 in one subpixel. Referring to FIG. 1, FIG. 3A is an enlarged cross-sectional view of a portion surrounded by a wavy line 29. Here, the liquid crystal display panel 20 is assumed to be a FFS (Fringe Field Switching) liquid crystal display panel as an example.

  As described above, the liquid crystal display panel 20 is configured by sealing liquid crystal between the substrate 1 and the substrate 2. On the inner surface of the substrate 1, a common electrode 5 is formed on the entire surface by a transparent conductive member such as ITO (Indium-tin-oxide). On the inner surface of the common electrode 5, an insulating layer 7 is formed on the entire surface with acrylic resin or the like. A pixel electrode 8 is formed on the inner surface of the insulating layer 7 by a transparent conductive member such as ITO. On the other hand, a colored layer 6 is formed on the inner surface of the substrate 2. An alignment film 9 is formed on the inner surface of the colored layer 6.

  FIG. 3B shows a plan view of the pixel electrode 8. As shown in FIG. 3B, the pixel electrode 8 has a comb shape. Specifically, the pixel electrode 8 is composed of a conductive portion 8a, a conductive portion 8b, a conductive portion 8c, a conductive portion 8d, and a conductive portion 8e that are arranged in a straight line and have a linear shape. These conductive portions are integrally formed. The liquid crystal display panel 20 generates a horizontal electric field (lateral electric field) E between the conductive portions 8 a to 8 e of the pixel electrode 8 and the common electrode 5.

  In FIG. 2, the pixel electrode 8 is electrically connected to some terminals of the driver IC 21 through the wiring 23. The common electrode 5 is electrically connected to a terminal corresponding to COM of the driver IC 21 (hereinafter simply referred to as “COM terminal”) through the wiring 25. The driver IC 21 controls the magnitude of the electric field E based on a control signal supplied from an external electronic device via the FPC 22. In the horizontal electric field type liquid crystal display panel 20, by controlling the magnitude of the electric field E, the alignment state of the liquid crystal molecules in the liquid crystal 4 is changed, and the gradation on the display screen is changed.

  As can be seen from the above, in the horizontal electric field type liquid crystal display panel 20, electrodes such as the pixel electrode 8 and the common electrode 5 are formed only on the inner surface of the substrate 1, and electrodes are formed on the inner surface of the substrate 2. Not. Therefore, for example, when an electric charge is applied to the outer surface of the substrate 2 due to external static electricity or the like, an electric field is generated between the substrate 1 and the substrate 2, and the liquid crystal molecules of the liquid crystal 4 Will be affected. As a result, the liquid crystal display panel 20 cannot perform an appropriate display.

  Therefore, in the liquid crystal device 100 according to the present embodiment, as described in detail below, the antireflection film 13 provided on the outer surface of the substrate 2 is made electrically conductive and electrically grounded, so that the external The liquid crystal device 100 is shielded and shielded from static electricity.

(Configuration of antireflection film)
Next, the configuration of the antireflection film 13 will be described in detail with reference to FIGS. FIG. 4 shows an enlarged cross-sectional view of the antireflection film 13. Referring to FIG. 1, FIG. 4 is an enlarged cross-sectional view of a portion surrounded by a wavy line 28.

  The antireflection film 13 has a structure in which high refractive index thin film layers and low refractive index thin film layers are alternately laminated. Therefore, specifically, as shown in FIG. 4, the antireflection film 13 has a structure in which thin film layers 13a to 13d are laminated. Here, the thin film layers 13a to 13d are high refractive index thin film layers or low refractive index thin film layers, respectively. As a material for the thin film layers 13a to 13d, an inorganic compound such as an oxide, sulfide, fluoride, or nitride is used. These thin film layers 13a to 13d have different refractive indexes depending on their materials, and can be formed as an antireflection film by laminating a plurality of layers with specific film thicknesses with thin films having different refractive indexes.

  As a material for the low refractive index thin film layer, for example, silicon dioxide or magnesium fluoride is used. As the material for the high refractive index thin film layer, for example, titanium dioxide, indium oxide, zinc sulfide, or the like is used.

  As shown in FIG. 4, the antireflection film 13 cancels the light L1 incident and reflected on the surface of the substrate 2 by interfering with the light L2 incident on the boundary between the thin film layers and reflected, thereby causing the light L1. It has a function to reduce the brightness of.

  In the liquid crystal device 100 according to the present embodiment, among the thin film layers 13a to 13d, the thin film layer 13d on the outermost surface is formed of a conductive material. Therefore, examples of the material for the thin film layer 13d include indium oxide, zinc oxide, and tin oxide, or two or three kinds of mixed oxides thereof.

  As shown in FIG. 4, one end of the wiring 26 is attached to one end of the thin film layer 13d. The wiring 26 is formed using a metal paste such as a silver paste, for example. Thereby, the thin film layer 13d is electrically connected to the wiring 26. As shown in FIG. 2, the other end of the wiring 26 is electrically connected to the COM terminal of the driver IC 21. Thereby, the thin film layer 13d is electrically connected to the COM terminal. The COM terminal is electrically connected to the ground line in the FPC 22 through the wiring 24. Therefore, the thin film layer 13d is electrically grounded. By doing so, the antireflection film 13 has electrical conductivity and is electrically grounded.

  As described above, in the liquid crystal device 100 according to the present embodiment, the antireflection film 13 has electrical conductivity and is electrically installed. Accordingly, the liquid crystal device 100 is shielded and shielded from external static electricity by the antireflection film 13, so that an electric field can be prevented from being generated between the substrate 1 and the substrate 2. In particular, in the liquid crystal device 100 using the horizontal electric field type liquid crystal display panel 20, it is possible to prevent an appropriate display from being prevented due to external static electricity or the like by shielding the shield in this way. In addition, in the liquid crystal device 100 according to the present embodiment, since it is not necessary to newly provide a conductive layer and provide conduction to the metal frame in order to provide a shielding function, the thickness of the device can be reduced. That is, the liquid crystal device 100 according to the present embodiment has both an antireflection function and a shielding function and can be thinned.

  In the liquid crystal device 100 according to this embodiment, as described above, the antireflection film 13 is formed on the outer surface of the substrate 2, and the polarizing plate 12 a is installed on the outer surface of the antireflection film 13. It is supposed to. This is because it is preferable to form the antireflection film 13 directly on the outer surface of the substrate 2 because the luminance of reflected light reflected on the surface of the substrate 2 can be effectively suppressed. Therefore, it goes without saying that even if the polarizing plate 12a is provided on the outer surface of the substrate 2 and the antireflection film 13 is formed on the outer surface of the polarizing plate 12a, the same effect as in the present invention can be obtained.

  In the liquid crystal device 100 according to the present embodiment, as shown in FIGS. 2 and 4, the area of the polarizing plate 12 a is smaller than the area of the antireflection film 13, and the polarizing plate 12 a On the surface of 13, an area 30 having a predetermined size is installed from the side where the driver IC 21 is installed. In this way, when the wiring 26 is formed by applying a metal paste, the metal paste can be applied on the surface of the thin film layer 13d, and the conduction between the wiring 26 and the thin film layer 13d is ensured. Can be taken.

  Furthermore, in the liquid crystal device 100 according to the present embodiment, the antireflection film 13 is formed such that the thin film layer 13d on the outermost surface among the thin film layers 13a to 13d is formed of a conductive material. It is not limited to. In short, if at least one of the thin film layers 13a to 13d is formed of a conductive material and is electrically grounded, the same effect as the present invention can be obtained. Needless to say.

[Modification]
Next, a modified example of the liquid crystal device 100 according to the present embodiment will be described.

  FIG. 5 is a plan view of the liquid crystal device 100 according to the first modification. In the liquid crystal device 100 according to the above-described embodiment, as shown in FIG. 2, the antireflection film 13 is electrically connected to the COM terminal of the driver IC 21 through the wiring 26. However, the present invention is not limited to this. Instead, it goes without saying that instead of being directly electrically connected to the ground wiring GND of the FPC 22 through the wiring 26a, as shown in FIG. Also by this, the antireflection film 13 is electrically grounded.

  FIG. 6 is an enlarged cross-sectional view of the antireflection film 13 in the liquid crystal device 100 according to the second modification. In the liquid crystal device 100 according to the above-described embodiment, at least one thin film layer among the thin film layers 13a to 13d of the antireflection film 13 is formed of a conductive material, but is not limited thereto. Instead, as shown in FIG. 6, it may have a conductive film 13e coated with conductive particles on its surface. Even in this case, the same effect as that of the present invention can be obtained as long as the conductive film 13e is electrically grounded. In FIG. 6, the conductive film 13 e is electrically grounded by being electrically connected to the COM terminal of the driver IC 21 via the wiring 26. Note that indium, tin, and antimony are used as the conductive particles.

  Furthermore, in the above-described embodiment, the liquid crystal display panel 20 is an FFS liquid crystal display panel, but is not limited to this, and instead is an IPS (In-Plane Switching) liquid crystal display panel. Needless to say, there may be. Furthermore, the liquid crystal display panel 20 is not limited to a horizontal electric field type liquid crystal display panel, but can be applied to another type of liquid crystal display panel such as a VA (Vertical Aligned) type instead. It is.

[Electronics]
Next, specific examples of electronic devices to which the liquid crystal device 100 according to the present invention can be applied will be described with reference to FIG.

  First, an example in which the liquid crystal device 100 according to the present invention is applied to a display unit of a portable personal computer (so-called notebook personal computer) will be described. FIG. 7A is a perspective view showing the configuration of this personal computer. As shown in the figure, the personal computer 710 includes a main body 712 having a keyboard 711 and a display 713 to which the liquid crystal device 100 according to the present invention is applied.

  Next, an example in which the liquid crystal device 100 according to the present invention is applied to a display unit of a mobile phone will be described. FIG. 7B is a perspective view showing the configuration of the mobile phone. As shown in the figure, a cellular phone 720 includes a plurality of operation buttons 721, a receiving port 722, a transmitting port 723, and a display unit 724 to which the liquid crystal device 100 according to the present invention is applied.

  Note that, as an electronic device to which the liquid crystal device 100 according to the present invention can be applied, in addition to the personal computer shown in FIG. 7A and the mobile phone shown in FIG. Monitor direct-view video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, digital still cameras, etc.

It is sectional drawing of the liquid crystal device which concerns on this embodiment. It is a top view of the liquid crystal device concerning this embodiment. It is sectional drawing and a top view in a sub pixel of a liquid crystal device concerning this embodiment. It is sectional drawing of an antireflection film. The top view of the liquid crystal device which concerns on a 1st modification is shown. The expanded sectional view of the liquid crystal device concerning the 2nd modification is shown. It is the schematic which shows the electronic device to which the illuminating device of this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Illuminating device, 11 Light guide plate, 12a, 12b Polarizing plate, 13 Antireflection film, 15 Light source part, 16 LED, 20 Liquid crystal display panel, 100 Liquid crystal device

Claims (5)

A horizontal electric field type liquid crystal display panel in which liquid crystal is sandwiched between two substrates;
An antireflection film that is disposed on the opposite side of the liquid crystal side of the outer substrate of the two substrates, and in which a thin film layer having a high refractive index and a thin film layer having a low refractive index are alternately laminated;
A polarizing plate disposed in an upper layer of the antireflection film ,
The antireflection film is formed wider than the area of the polarizing plate, and among the thin film layers constituting the antireflection film, at least an outermost thin film layer has conductivity and a region where the thin film layer is exposed. liquid crystal device that is electrically grounded through. 2. The liquid crystal device according to claim 1, wherein the substrate on the outer surface side on which the antireflection film is formed is a substrate on which a common electrode and a pixel electrode are not formed. A driver IC for driving the liquid crystal display panel;
The liquid crystal device according to claim 1, wherein the antireflection film is electrically connected to a COM terminal of the driver IC. A flexible substrate electrically connected to the liquid crystal display panel;
The liquid crystal device according to claim 1, wherein the antireflection film is electrically connected to a ground wiring of the flexible substrate. An electronic apparatus comprising the liquid crystal device according to any one of claims 1 to 4 in a display portion.

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