JPH1039335A - Liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent charge by static electricity from the outside and to enable display with high image quality by forming a light shielding film at a display part on a color filter forming substrate and a parting part around the film with a metal and further forming a metallic film at the outside of the parting part. SOLUTION: A light shielding Cr pattern 101 is formed at a display part on the inside of an upper glass substrate 100, a parting pattern 102 is formed around the display part and a Cr pattern 103 for making the potential of the substrate constant is further formed at the outside of the pattern 102. The surface potential of the color filter forming substrate is made constant even at the time of sprinkling spacers and the spacers are uniformly sprinkled. After sticking with a seal, <=±0.1μm cell thickness precision is attained and superior uniformity is ensured. The number of steps of gradation up to 64 can be reproduced. Since the light shielding Cr film has constant potential, charge by static electricity from the outside is prevented and display with high image quality is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal device.

[0002]

2. Description of the Related Art At present, most liquid crystal devices used in notebook personal computers, liquid crystal televisions and the like are TN (Twiste).
d Nematic) mode. However, the TN mode looks different depending on the viewing direction. As a method for improving the viewing angle characteristics, Japanese Patent Application Laid-Open No. 56-091277 and Japanese Patent Application Laid-Open No. 06-160878 disclose a method using an in-plane electric field.
A PS (In Plane Switching) mode has been proposed.

[0003] The operation principle of the IPS mode will be briefly described below. 4A and 4B are cross-sectional views showing the operation of the liquid crystal in the liquid crystal panel using the IPS mode.
(C) and (d) are front views thereof. FIG. 4 shows a TFT (Thin
FIG. 2 is a schematic diagram in which active elements such as a film transistor are omitted. This schematic diagram is a cross-sectional view of a portion XX ′ in FIG. 5 and an enlarged view of a portion surrounded by a dotted line. FIG.
This is a configuration diagram of a pixel. In this configuration diagram, a common electrode 5 is provided in one pixel.
2, two pixel electrodes 501 and one pixel electrode 501 exist in the longitudinal direction, but this is only a schematic drawing, and originally there are several common electrodes 502 and several pixel electrodes 501 in one pixel. . FIG. 4A is a cross-sectional view of the cell when no voltage is applied, and FIG. 4C is a front view. Among the pair of substrates 402 and 408, a linear common electrode 411 and a pixel electrode 410 are formed inside the lower substrate 408, and alignment films 404 and 406 for arranging liquid crystal molecules 405 are formed. Liquid crystal is sandwiched between the pair of substrates 402 and 408,
The liquid crystal molecules 405 are linear electrodes (common electrode 4) when no voltage is applied.
11, the pixel electrode 410) is uniformly oriented at an angle of 0 to 45 degrees with respect to the longitudinal direction of the pixel electrode 410). In FIG. 4, this angle is 30 degrees. Polarizing plates 4 are provided on both sides of the liquid crystal cell.
01.409 is arranged. The upper polarizing plate 401 has an absorption axis 414 parallel to the alignment direction of the liquid crystal, and a lower polarizing plate 409.
Are arranged vertically. This state is a black display state. As the liquid crystal material, a material having a positive dielectric anisotropy was used. Next, when an electric field 415 is applied, the liquid crystal molecules 405 try to align their major axes in the direction of the electric field 415 as shown in FIGS. It has an angle corresponding to the strength of the electric field.
By controlling the birefringence of the liquid crystal cell according to the intensity of the applied electric field, a monochrome display can be performed. However, since the pixel electrode 410 and the common electrode 411 for applying an electric field to the liquid crystal are formed only on one substrate and no electrodes are formed on the other substrate, it is easy to be charged by static electricity. Problems arise. When charged by static electricity, the orientation of the liquid crystal is disturbed, and high-quality display cannot be performed. Further, once charged by static electricity, no electrode is present on one of the substrates, so that the static electricity cannot be easily removed. Also, a method for avoiding this is proposed in Japanese Patent Application No. 8-57945. According to this method, a conductive film such as a transparent electrode is formed on a light-shielding film made of a metal on a substrate on which a color filter is formed or a back surface of a color filter substrate, and the conductive film keeps the substrate potential constant. This method has a considerable effect on static electricity.

[0004]

However, when a metal film is used, since the light-shielding film of the color filter substrate is simply used, the metal portion is limited to the display region and the parting-off portion, and particularly the seal around the substrate is particularly limited. It is not possible to maintain a constant potential from the portion where the voltage is applied to the end. In addition, the spacers for controlling the cell thickness are generally sprayed on the color filter substrate side to prevent mixing of static electricity.However, due to the potential unevenness in this plane, the number of spacers is biased particularly around the periphery of the substrate. This causes cell thickness unevenness. This means that I
In the PS mode, there is a problem of gradation reproducibility at the time of display. Further, when a transparent electrode or another conductor is provided, the number of steps increases and the cost increases.

The present invention has been made to solve the above-mentioned problems, and is a further improvement of Japanese Patent Application No. 8-57945. The invention is less affected by static electricity and is less likely to be charged. Accordingly, an object of the present invention is to realize a high-quality liquid crystal device at low cost.

[0006]

According to the first aspect of the present invention,
A liquid crystal alignment film is formed directly or via an insulating layer on a substrate on which a scanning signal line, a video signal line, a pixel electrode, a common electrode, and an active element are formed, and the substrate is provided with a color filter and a liquid crystal alignment film. A liquid crystal is sandwiched between the two substrates while being adhered to each other by a seal between the two substrates, and the pixel electrode and the common electrode provide an electric field substantially parallel to the substrate surface with respect to the liquid crystal layer. In a liquid crystal device comprising a driving means for driving the liquid crystal and a polarizing plate for changing optical characteristics according to an alignment state of the liquid crystal layer, a light shielding film of a display portion of a substrate on which the color filter is formed. And a parting part around the parting part is made of metal, and a metal film is formed outside the parting part.

Chromium (Cr) is suitable for the metal light shielding film.

According to a second aspect of the present invention, in the liquid crystal device according to the first aspect, the metal film provided outside the parting line is formed at least up to the seal portion.

According to a third aspect of the present invention, in the display device of the first aspect, the parting-off portion is formed at least up to the seal portion.

According to the above construction, it is possible to prevent unevenness in charging of the substrate on which the color filter is formed, promote uniform dispersion of the scattered spacers, and provide a display having excellent uniformity without disturbance of liquid crystal alignment at a relatively low cost. This has the effect of making it possible.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a view showing a main part of the configuration of a liquid crystal device according to the first embodiment of the present invention.
(A) is a schematic front view of the color filter forming substrate 100, and (b) is an enlarged sectional view of the liquid crystal device. First, the configuration will be described. It has a structure in which two transparent glass substrates 100 and 107 having a thickness of 0.7 or 1.1 mm are stacked. The upper glass substrate 100 has a display part light-shielding pattern 101 made of chromium (Cr) on the inner surface, a parting pattern 102 around the display part, and a Cr pattern 103 around the parting periphery to keep the substrate potential constant. Denotes a red-green-blue (RGB) color filter 104 and an alignment film 105
Are sequentially formed, and a polarizing plate 106 is disposed outside. The lower glass substrate 107 has the common electrode 1 inside.
08, insulating layer 109, pixel electrode 110 and alignment film 111
Are formed, and a polarizing plate 112 is disposed outside. As shown in FIG. 5, the scanning signal line 503 and the video signal line 5
04 runs in a matrix and a TFT element 505 is formed at the intersection. In one pixel, the common electrode 502 and the pixel electrode 501 are arranged in different layers via an insulating layer. In FIG. 1, reference numeral 115 denotes a seal, which is a transparent glass substrate 1.
00 and 107 are fixed. Spacers 116 made of resin or metal oxide balls for controlling the cell thickness are dispersed between the substrates. Further, 113 indicates the direction of the electric field. The cell thickness was 4 to 5 μm, and a nematic liquid crystal having a refractive index anisotropy Δn = 0.070 and a positive dielectric anisotropy was used as the liquid crystal material 114. The distance between the linear common electrode 108 and the pixel electrode 110 was 5 to 20 μm, and the line width of both electrodes was 3 to 10 μm. When no voltage is applied to the liquid crystal molecules, the linear electrodes (common electrode 108, pixel electrode 11
The rubbing orientation treatment was performed so as to have an angle of 30 degrees with the longitudinal direction of 0). Polarizing plate 10 of upper glass substrate 100
Reference numeral 6 indicates that the absorption axis is parallel to the alignment direction of the liquid crystal, and the polarizing plate 112 of the lower glass substrate 107 is vertically arranged. This state is a black display state, and display can be performed according to the voltage applied from the external driving means. A backlight light source is arranged on the lower substrate 107 side, and Cr
The display part light-shielding film 101, the parting-off 102 or the pattern 103 outside the parting-off is the common electrode 1 on the lower glass substrate 107.
It is short-circuited via the silver paste outside the display area of the liquid crystal cell so as to have the same potential as 08. In the liquid crystal device thus prepared, the potential of the surface of the color filter forming substrate was constant even when the spacers were sprayed, and the spacers were uniformly sprayed (± 15% in the plane). Also, even after bonding with a seal, the cell thickness accuracy was within ± 0.1 μm, resulting in a liquid crystal device with excellent uniformity, and the number of gradations could be reproduced up to 64 gradations. Even when an electrostatic withstand voltage test of about 1 kV was performed using this apparatus, good display was achieved without any charging. According to the configuration of this embodiment, since the metal light-shielding film Cr has a constant potential (ground potential), the color filter forming substrate is not charged by external static electricity or the like, and a high-quality display is possible. Further, since the ground potential is a potential already existing in the liquid crystal device, it is not necessary to newly create the ground potential.
FIG. 6 shows a light-shielding film structure of a conventional color filter forming substrate for comparison. When the spacers were scattered using this substrate 600, potential unevenness occurred around the boundary of the parting pattern 602, and the number variation became ± 30%.
When a panel similar to that of FIG. 1 was prepared, the cell thickness accuracy was ± 0.3 μm, and the gradation reproducibility was somewhat insufficient.

(Embodiment 2) FIG. 2 is a view showing a main part of a structure of a liquid crystal device according to the second aspect of the present invention, and is a plan view of a color filter forming substrate. In this embodiment,
This is a structure in which a Cr pattern 203 formed outside the parting line 202 of the color filter forming substrate 200 to stabilize the potential is provided up to a portion corresponding to the seal portion 115 in FIG. Is formed up to. According to this embodiment, since the potential on the entire surface of the color filter substrate can be kept constant, the variation in the number when the spacers are sprayed can be suppressed to within ± 10%, and this substrate is combined with the same structure as in the first embodiment. The liquid crystal device prepared in this manner had a cell thickness accuracy of ± 0.05 μm, no alignment failure due to static electricity of the liquid crystal, and extremely good gradation reproducibility. Further, even when an electrostatic withstand voltage test was performed with static electricity of about 1 kV, good display was performed without any charging. According to the configuration of this embodiment, since the metal light-shielding film Cr has a constant potential (ground potential), the color filter forming substrate is not charged by external static electricity or the like, and a high-quality display is possible. Further, since the ground potential is a potential already existing in the liquid crystal device, it is not necessary to newly create the ground potential.

(Embodiment 3) FIG. 3 is a view showing a main part of the structure of a liquid crystal device according to a third embodiment of the present invention.
It is a top view of a color filter formation substrate. In this embodiment, the parting pattern 302 of the color filter substrate 300 is used.
Is provided up to the portion corresponding to the seal portion 115 in FIG. According to this embodiment, since the potential on the entire surface of the color filter substrate can be kept constant, the variation in the number when the spacers are scattered can be suppressed to within ± 13%. The liquid crystal device prepared in this manner had a cell thickness accuracy of ± 0.08 μm, no alignment defect due to static electricity of the liquid crystal, and extremely excellent gradation reproducibility. Further, even when an electrostatic withstand voltage test was performed with static electricity of about 1 kV, good display was performed without any charging.
According to the configuration of this embodiment, since the metal light-shielding film Cr has a constant potential (ground potential), the color filter forming substrate is not charged by external static electricity or the like, and a high-quality display is possible. Further, since the ground potential is a potential already existing in the liquid crystal device, it is not necessary to newly create the ground potential.

In the drawings in the present embodiment, the display portion light-shielding portion, the parting-off, and the metal pattern outside the parting-out are distinguished by hatching, but these patterns are formed simultaneously by the same film. Furthermore, the pattern shape of the parting-out outer metal film is arbitrary, such as straight, lattice, solid, and random. However, if possible, a pattern that is constant and close to the pattern rule of the display part light-shielding film has a stable in-plane potential. Easy and desirable.

As described above, with the configuration of the liquid crystal device as in the present embodiment, the color filter forming substrate is not charged by external static electricity or the like, and high quality display is possible.

In this embodiment, the potential of the Cr film is set to the ground potential, but may be set to the common electrode potential, the center potential of the video signal, the non-selection potential of the scanning signal, or the logic potential of the external driving means. Alternatively, the upper and lower substrates may be set at a floating potential without being electrically connected. Furthermore, Ta other than Cr,
It has been confirmed that a similar effect can be obtained with a metal such as Al, Au, Ni, or an alloy film of these metals.

[0018]

As described above, according to the liquid crystal device of the present invention, a liquid crystal alignment film is directly or directly formed on a substrate on which a scanning signal line, a video signal line, a pixel electrode, a common electrode, and an active element are formed. Formed with an insulating layer interposed therebetween, the substrate is disposed so as to face another substrate on which a color filter and a liquid crystal alignment film are formed, a liquid crystal is sandwiched between the two substrates, and the pixel electrode and the common electrode are In a liquid crystal device comprising a driving unit for driving the liquid crystal and a polarizing plate for changing optical characteristics depending on an orientation state of the liquid crystal layer, the liquid crystal device is configured so that an electric field substantially parallel to the substrate surface can be applied to the liquid crystal layer. The light-shielding film of the display portion of the substrate on which the color filter is formed and the surrounding part, and a metal film is also formed outside the parting portion, and the metal film has a constant potential. Forming substrate becomes constant potential will not attempt from being electrostatically charged and thus a high-quality image can be displayed.

[0019]

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a liquid crystal device of the present invention.

FIG. 2 is a schematic plan view showing an example of a color filter forming substrate of the liquid crystal device of the present invention.

FIG. 3 is a schematic plan view showing another example of the color filter forming substrate of the liquid crystal device of the present invention.

FIG. 4 is an explanatory diagram of an IPS mode.

FIG. 5 is a configuration diagram of one pixel.

FIG. 6 is a schematic plan view of a conventional color filter forming substrate.

[Explanation of symbols]

 Reference Signs List 100: color filter forming substrate 101: display part light-shielding film 102: parting-off part 103: parting-out outer pattern 104: color filter 105, 111 ... orientation film 106, 112 ... Polarizing plate 108: Common electrode 109: Insulating layer 110: Pixel electrode 113: Electric field 114: Liquid crystal 115: Seal 116: Spacer 200: Color filter forming substrate 201 .. Display part light-shielding film 202: part-off part 203 ... parting outside pattern 204 ... color filter 300 ... color filter forming substrate 301 ... display part light-shielding film 302 ... part-off part 303. ..Partition outer pattern 304: color filters 401, 409: polarizing plates 402, 408: substrate 403 Color filters 404, 406 Alignment film 405 Liquid crystal molecules 407 Insulating layers 410, 501 Pixel electrodes 411, 502 Common electrodes 412, 504 Video signal lines (source Line) 413: absorption axis of lower polarizing plate 414: absorption axis of upper polarizing plate 415: electric field 503: scanning signal line (gate line) 505: TFT element 600: color Filter forming substrate 601: display part light-shielding film 602: parting part 604: color filter

Claims (3)

[Claims] An alignment film for liquid crystal is formed directly or via an insulating layer on a substrate on which a scanning signal line, a video signal line, a pixel electrode, a common electrode and an active element are formed. Liquid crystal is sandwiched between the two substrates on which the alignment film is formed, and the two substrates are bonded to each other with a seal, and the pixel electrode and the common electrode are substantially separated from the liquid crystal layer by the substrate. In a liquid crystal device comprising a driving means for driving the liquid crystal and a polarizing plate for changing optical characteristics depending on an alignment state of a liquid crystal layer, a liquid crystal device comprising a substrate on which the color filter is formed is configured so that an electric field parallel to a plane can be applied. A liquid crystal device, wherein a light-shielding film of a display portion and a parting portion around the light-shielding film are formed of metal, and a metal film is formed outside the parting portion. 2. The liquid crystal device according to claim 1, wherein the metal film provided outside the parting part is formed at least up to the seal part. 3. The liquid crystal device according to claim 1, wherein said parting-off portion is formed at least up to said seal portion.