JP2008129324A - Color filter and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter for an IPS mode liquid crystal display device and an IPS mode liquid crystal display device having an electrostatic shielding effect and a structure capable of reducing the thickness of the liquid crystal display device.
SOLUTION: A transparent substrate, a plurality of colored pixels formed on the transparent substrate, a transparent conductive layer formed on the colored pixel and a transparent substrate around the colored pixel, and the transparent conductive layer on the transparent conductive layer And an overcoat layer formed in a region corresponding to the colored pixel, wherein the overcoat layer is not formed in a peripheral portion of the transparent conductive layer.
[Selection] Figure 1

Description

  The present invention relates to a color filter and a liquid crystal display device including the color filter, and more particularly to a color filter for an IPS liquid crystal display device and an IPS liquid crystal display device including the color filter.

  Conventionally, a TN liquid crystal display device that switches liquid crystals using an electric field perpendicular to a glass substrate has been used. However, this TN liquid crystal display device has a problem that the viewing angle is narrow. As an alternative to this TN liquid crystal display device, there is an IPS (in-plane switching) liquid crystal display device that switches liquid crystal using a horizontal electric field on a glass substrate.

  This IPS liquid crystal display device has the advantage that the liquid crystal molecules do not stand up obliquely, so that the change in optical characteristics depending on the viewing angle is small and a wide viewing angle can be obtained.

  The structure of such an IPS liquid crystal display device is shown in FIG. As shown in FIG. 3, the IPS liquid crystal display device includes a color filter substrate 11 and a TFT drive electrode substrate 12 facing each other and a liquid crystal layer 13 sealed between them. The color filter substrate 11 is provided with a light shielding layer (not shown) and a colored layer 15 on a predetermined region of the glass substrate 14, an overcoat layer 16 is formed on the colored layer 15, and ITO is formed on the back surface of the glass substrate 14. It is configured by forming the layer 17. (For example, JP 2000-250023 A). The TFT drive electrode substrate 12 is provided with a plurality of electrodes so that a horizontal transverse electric field is generated on the substrate.

  At present, thinning of the liquid crystal panel is desired, but this thinning is performed by chemically etching the back surface of the glass substrate of the color filter. However, in the IPS liquid crystal display device as shown in FIG. 3, since the ITO film 17 exists on the back surface of the glass substrate 14 of the color filter 11, it is difficult to reduce the thickness by chemical etching.

The ITO film 17 on the back surface of the glass substrate 14 of the color filter 11 is grounded via the liquid crystal panel body, and plays a role of preventing static electricity in the manufacturing process of the liquid crystal panel. In addition, after the liquid crystal panel is completed, even if a person charged with static electricity touches it, the static electricity can be released, so that it is possible to prevent the TFT of the TFT drive substrate from being destroyed by static electricity. .
JP 2000-250023 JP

  The present invention has been made under the circumstances as described above, and has a structure capable of reducing the thickness of a liquid crystal display device, and can also exhibit an electrostatic shielding effect, and a color filter for an IPS liquid crystal display device and an IPS mode liquid crystal display. An object is to provide an apparatus.

  In order to solve the above-mentioned problems, a first aspect of the present invention is a transparent substrate, a colored layer composed of a plurality of colored pixels formed on the transparent substrate, and a transparent substrate on and around the colored layer. A transparent conductive layer formed thereon, and an overcoat layer formed in a region corresponding to the colored layer on the transparent conductive layer, and the overcoat layer is formed in a peripheral portion of the transparent conductive layer A color filter for an IPS mode liquid crystal display device is provided.

  According to a second aspect of the present invention, there is provided an IPS liquid crystal display device comprising the color filter described above.

  According to the first aspect of the present invention, since the conductive layer is formed not on the back surface of the transparent substrate but on the colored layer, it is possible to reduce the thickness of the liquid crystal display device by polishing the transparent substrate. Since the overcoat layer is not formed in the peripheral portion, the portion can be grounded. Therefore, a color filter for an IPS mode liquid crystal display device that can also exhibit an electrostatic shielding effect is provided.

  In addition, according to the second aspect of the present invention, there is provided an IPS liquid crystal display device that is thinned and can exhibit an electrostatic shielding effect.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a cross-sectional view showing the structure of an IPS liquid crystal display device including a color filter according to the first embodiment of the present invention. As shown in FIG. 1, the IPS liquid crystal display device includes a color filter substrate 1 and a TFT drive electrode substrate 2 which are arranged to face each other and a liquid crystal layer 3 sealed between them. The color filter substrate 1 is provided with a light shielding layer (not shown) and a colored layer 5 on a predetermined region of the glass substrate 4, an ITO layer 6 is provided on the colored layer 5 and on the surrounding glass substrate 4, The overcoat layer 7 is formed on the ITO layer 6.

  The color filter substrate 1 having the above structure is different from the conventional color filter substrate 1 in that the ITO layer 17 is provided on the back surface of the glass substrate 14 as shown in FIG. It is provided on the colored layer 5. According to the color filter substrate 1 having such a structure, since there is no ITO film on the back surface of the glass substrate 4, it is possible to polish the back surface of the glass substrate 4, thereby thinning the glass substrate 4. Therefore, the liquid crystal display device can be thinned.

  The TFT drive electrode substrate 2 is provided with a plurality of electrodes so that a horizontal electric field in the horizontal direction is generated on the substrate.

  Next, a method for manufacturing the color filter substrate 1 described above will be described with reference to FIG.

  FIG. 2 shows a configuration in which the laminated structure of the colored layer 5, the ITO layer 6, and the overcoat layer 7 described above is provided on the glass substrate 4.

  First, the glass substrate 4 for LCD (thickness 0.7 mm) made of non-alkali glass (1737G, manufactured by Corning) is cleaned with an alkali cleaner or the like. Next, in order to form a black matrix layer (resin BM layer) made of resin, a photosensitive resin (BKIS series photoresist, manufactured by Nippon Steel Co., Ltd.) in which carbon black is dispersed is applied to the surface of the glass substrate 4 using a coater. To do. The film thickness is such that the film thickness of the completed resin BM layer is 1 to 2 μm.

  Next, the photosensitive resin layer surface is exposed with a predetermined pattern through a photomask, developed with an alkali developer, and post-baked at a temperature of about 200 to 250 ° C. for 1 hour, for example, to form a resin BM. A layer (not shown) is formed.

  Thereafter, a red pigment-dispersed photoresist is applied to the entire surface, the coated surface is exposed with a predetermined pattern through a photomask, developed and post-baked to form red pixels. Similarly, a green pixel layer and a blue pixel are formed, and a colored layer 5 including a red pixel, a green pixel layer, and a blue pixel is formed. As the pigment dispersion photoresists of red, green, and blue, CDP series pigment dispersion resists (manufactured by Toyo Ink Manufacturing Co., Ltd.) were used. Moreover, the thickness of each pixel of red, green, and blue is, for example, 0.6 to 3.0 μm.

  Next, after forming the ITO layer 6 on the colored layer 5 and the surrounding glass substrate 4 by a sputtering method, annealing treatment is performed at 200 to 250 ° C., for example. The thickness of the ITO film 6 is, for example, 100 to 3000 angstroms.

  An overcoat photoresist is applied on the ITO film 6 thus formed, the coated surface is exposed in a predetermined pattern through a photomask, developed and post-baked, and an overcoat layer 7 is formed. Form. As a result, a color filter substrate having four faces of the color filter having the structure shown in FIG. 2 is obtained. The overcoat layer 7 is formed in a region corresponding to the colored layer 5. That is, the peripheral region of the ITO film 6 is made a non-overcoat region by patterning. As the overcoat photoresist, KMH series photoresist material (manufactured by Osaka Organic Chemical Industry Co., Ltd.) was used. The film thickness of the overcoat layer 7 is, for example, 1 to 5 μm.

  Then, after forming a photo spacer on the periphery of each overcoat layer 7 by photolithography, the color filter substrate having four color filters attached thereto is bonded to a separately prepared TFT substrate with an adhesive.

  Subsequently, the back surface of the glass substrate 4 having a structure bonded in this manner is polished to reduce the film thickness to 0.3 to 0.5 mm. Polishing can be performed by chemical etching using a hydrofluoric acid-based etching solution, or mechanical polishing using an Oscar-type mechanical polishing method or a sandblasting method.

  The structure in which the glass substrate 4 is thinned in this way is then cut into four cells. Then, liquid crystal is filled in the voids in these cells, and a liquid crystal display panel as shown in FIG. 1 is produced. In this liquid crystal display panel, since the overcoat layer 7 is not formed on the periphery of the ITO film 6, the portion can be electrically connected to the liquid crystal display panel body, and the liquid crystal display panel body is grounded. Therefore, the electrostatic shielding effect with respect to the liquid crystal display panel is exhibited.

  Moreover, the thinning of the liquid crystal display panel can be achieved by polishing the back surface of the glass substrate 4.

1 is a cross-sectional view illustrating a configuration of a liquid crystal display device including a color filter substrate according to an embodiment of the present invention. FIG. 3 is a perspective view showing a configuration in which four color filters are provided on a substrate for obtaining the liquid crystal display device shown in FIG. 1. Sectional drawing which shows the structure of a liquid crystal display device provided with the conventional color filter board | substrate.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,11 ... Color filter substrate, 2,12 ... TFT drive electrode substrate, 3,13 ... Liquid crystal layer, 4,14 ... Glass substrate, 5,15 ... Colored layer, 6, 17 ... ITO layer, 7, 16 ... Over Coat layer.

Claims (2)

  A transparent substrate, a colored layer comprising colored pixels of a plurality of colors formed on the transparent substrate, a transparent conductive layer formed on the colored layer and its surrounding transparent substrate, and the transparent conductive layer on the transparent conductive layer And an overcoat layer formed in a region corresponding to the colored layer, wherein the overcoat layer is not formed in the periphery of the transparent conductive layer.   An IPS liquid crystal display device comprising the color filter according to claim 1.

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