JP2009186824A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress rolling of a spherical spacer when spherical spacer arrangement by an inkjet method is performed in a COA liquid crystal display device. <P>SOLUTION: A third colored layer 25c is stacked on a base portion 40 comprising first and second colored layers 25a and 25b, and a tapered portion 28a is provided which can suppress rolling of the spherical spacer 32. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that suppresses rolling of a spherical spacer.

  In recent years, in order to make the thickness of the liquid crystal layer between the array and the counter substrate (hereinafter referred to as a gap) constant, a liquid crystal display device using a resin sphere having a uniform diameter (hereinafter referred to as a spherical spacer) has been put into practical use. As a spraying method, an inkjet method has been studied from the viewpoint of productivity and accuracy (Patent Document 1).

  In the inkjet method, a dispersion liquid containing spherical spacers is integrally discharged while moving a nozzle head in which a plurality of nozzle holes are arranged in a row with respect to the substrate at predetermined intervals. And when a dispersion liquid evaporates, a spherical spacer will be arrange | positioned in predetermined places, such as an auxiliary capacity formation part.

  However, the spacer has a spherical shape and has a feature that it easily rolls because it is pulled by the surface tension of the dispersion, that is, the spread of the dispersion. Therefore, there is a problem that the position deviates from the planned position, enters the display area, fits into the through hole, and does not contribute to holding between the substrates.

In order to solve this problem, a technique has been studied in which a step is provided on the substrate to restrict rolling (Patent Document 2). The step is provided by using a wiring such as a scanning line or a signal line on the substrate, or a concave step between color filters on the black matrix.
JP 2004-145101 A JP 2006-243719 A

  However, the conventional steps described above use wiring or black matrix that has already been arranged, and cannot be intentionally formed in the non-display area where the spherical spacer is arranged. There is a drawback that it cannot be applied to an unenclosed color filter on array type liquid crystal display device (hereinafter referred to as COA type).

  The COA type is a useful technique in which a colored layer is provided on the array substrate to prevent misalignment with the counter substrate and improve the aperture ratio.

  Accordingly, an object of the present invention is to provide a liquid crystal display device having a recess that suppresses rolling of a spherical spacer applicable to the COA type.

  In order to achieve the above object, a liquid crystal display device according to an aspect of the present invention includes a plurality of scanning lines and signal lines provided on an array substrate, and a switching element provided at an intersection of the scanning lines and signal lines. And an organic insulation comprising first, second, and third colored layers formed on the array substrate so as to cover the scanning lines, the signal lines, and the switching elements and colored in different colors by a resist. A film electrode; a pixel electrode formed on the organic insulating film to form a display region; a through hole provided in the organic insulating film to electrically connect the pixel electrode and the switching element; and A counter substrate disposed oppositely, a spherical spacer disposed between the array substrate and the counter substrate, and holding between the two substrates; on the surface of the organic insulating film; and the display area A liquid crystal display device comprising: a tapered portion recessed at a predetermined interval in a portion other than a portion; and a liquid crystal layer sandwiched between the array substrate and the counter substrate, wherein the spherical spacer has a nozzle with respect to the array substrate. In the ink jet method, the dispersion liquid containing the spherical spacer is integrally ejected while being moved at predetermined intervals, and the tapered portion is arranged so as to suppress the rolling of the spherical spacer. .

  According to the present invention, it is possible to suppress rolling of the spherical spacers that are dropped and arranged by the inkjet method, and to contribute to holding between substrates.

  Embodiments of a liquid crystal display device according to the present invention will be described below with reference to the drawings. The COA type will be described as an example.

(Embodiment 1)
Embodiment 1 of a liquid crystal display device according to the present invention will be described with reference to FIGS. The same parts are denoted by the same reference numerals.

  FIG. 1 is a perspective view showing a liquid crystal display device according to the present invention, and FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG. 3 is an enlarged view of the array substrate 10 showing the relationship between the colored layers 25a, 25b, 25c, the through hole 27, and the tapered portion 28a when the portion indicated by the broken line (R) in FIG. 2 is viewed from the counter substrate 11 side. It is a top view.

  The liquid crystal display device includes an array substrate 10 having a display region 12, a counter substrate 11 disposed opposite to the array substrate 10 with a predetermined gap, and a driving LSI (not shown) that drives the display region 12. On the lower surface of the substrate 10, a backlight unit 13 made of an LED or the like serving as a light source is disposed.

  The array substrate 10 includes a transparent substrate 20a made of glass or the like, a multilayer thin film 21 formed on the transparent substrate 20a, and an alignment film (not shown). On the transparent substrate 20a, a plurality of signal lines 22 shown in FIG. 3 and scanning lines (not shown) are arranged in a grid pattern via a multilayer thin film 21. In addition, auxiliary capacitance lines 23 are arranged along each scanning line, and transparent conductive materials such as Indium, Tin, and Oxide (hereinafter referred to as ITO) such that the auxiliary capacitance lines 23 and the signal lines 22 substantially correspond to pixel openings. A pixel electrode 24 made of a material and constituting the display region 12 is provided.

  A switching element for controlling the pixel electrode 24 is formed at each intersection of the scanning line and the signal line 22, and an organic insulating film 25 that is a part of the multilayer thin film 21 is coated on the switching element.

  The organic insulating film 25 is colored with one of R, G, and B resists to form a first colored layer 25a, a second colored layer 25b, and a third colored layer 25c.

  The first colored layer 25a and the second colored layer 25b are formed only in the display area 12, but the third colored layer is added to the display area and a portion that is not a display area near the through hole 27 (hereinafter referred to as a non-display area). It is formed.

  A pixel electrode 24 is disposed on each colored layer 25a, 25b, 25c. The pixel electrode 24 is electrically connected to the switching element through a through hole 27 formed in each colored layer 25a, 25b, 25c.

  Here, a thin film transistor 26 (hereinafter referred to as TFT) composed of a gate electrode 26a, a source electrode 26b, and a drain electrode 26c is used as the switching element. The gate electrode 26a is electrically connected to the scanning line, and the source electrode 26b is electrically connected to the signal line 22.

  When a voltage is applied to the gate electrode 26a connected to the scan line, the source electrode 26b and the drain electrode 26c are brought into conduction, and the TFT 26 is turned on for a certain period. During this period, a signal necessary for image display is supplied from the signal line 22 and written at a predetermined timing.

  The drain electrode 26 c is electrically connected to the pixel electrode 24 through a through hole 27 formed in each colored layer 25 a, 25 b, 25 c of the organic insulating film 25.

  A tapered portion 28a, which will be described in detail later, is recessed in the peripheral portion of the through hole 27.

  The counter substrate 11 has a transparent substrate 20b made of glass or the like, and is disposed to face the array substrate 10. The counter substrate 11 has a transparent electrode 33 made of ITO and an alignment film (not shown) on the liquid crystal layer 30 side.

  The array substrate 10 and the counter substrate 11 are joined using a sealing material 29 in a frame region that is the periphery of the display region 12, and the liquid crystal layer 30 is formed in a region surrounded by the array substrate 10, the counter substrate 11, and the sealing material 29. Is formed.

  The sealing material 29 seals the liquid crystal layer 30, and a black matrix layer 31 (hereinafter referred to as a BM layer) is disposed inside the sealing material 29 as a light shielding layer.

  The distance between the array substrate 10 and the counter substrate 11 is held by a spherical spacer 32. The spherical spacer 32 is made of a resin having a uniform diameter and has a diameter of 3 to 6 μm.

  Further, polarizing plates (not shown) are disposed on the surfaces of the array substrate 10 and the counter substrate 11 that are opposite to the liquid crystal layer 30 side.

  The spherical spacer 32 is driven and arranged by an ink jet method. Hereinafter, a method for discharging the spherical spacer 32 will be described with reference to FIG.

  The ink jet apparatus is provided with a horizontal beam-like nozzle head, and nozzle holes are arranged at regular intervals on the lower surface of the nozzle head. The nozzle head moves at regular intervals along the direction of the signal lines 22 or the scanning lines of the array substrate 10 to discharge the dispersion liquid including the spherical spacers 32.

  Further, the nozzle head can be inclined at an arbitrary angle from the normal direction of the substrate surface of the array substrate 10 to a direction parallel to the substrate surface of the array substrate 10, and in this state, the signal head 22 or the scanning line is inclined. By moving intermittently while scanning the array substrate 10 in the along direction, the spherical spacer 32 can be disposed on the tapered portion 28a according to the present embodiment at the periphery of the through hole 27.

  Hereinafter, the tapered portion 28a, which is a characteristic part of the present embodiment, will be described in detail with reference to FIGS. In addition, the same part is shown with the same code | symbol.

  FIG. 4 is an enlarged cross-sectional view taken along line BB in FIG.

  The first colored layer 25 a has a first base portion 40 a made of the same material as that of the first colored layer 25 a in the vicinity of the through hole 27. The second colored layer 25b has a second base portion 40b made of the same material as that of the second colored layer 25b in the vicinity of the through hole 27.

  Further, a portion of the third colored layer 25c formed in a non-display area such as the vicinity of the through hole 27 is laminated on the first and second base portions 40a and 40b.

  Therefore, the portion 25c2 of the third colored layer 25c located above the first and second base portions 40a and 40b is a portion 25c1 of the third colored layer 25c that is not stacked on the first and second base portions 40a and 40b. Higher than As a result, a height difference is created, that is, the tapered portion 28a is formed.

  The depth (d1) of the tapered portion 28a differs depending on the thickness of the base portion 40 and the surface area of the interface of the portion 25c2 of the third colored layer 25c located above the base portion 40. For example, when the surface area is large, the third colored layer 25c to be laminated is fixed to the base portion 40, and the depth (d1) tends to be substantially equal to the thickness of the first and second base portions 40a and 40b. As the size becomes smaller, the third colored layer 25c to be laminated tends to spread to the periphery, and the tapered portion 28a tends to become shallow.

  When the first and second base portions 40a and 40b are formed in the same process as the first and second colored layers 25a and 25b, respectively, the first and second base portions 40a and 40b are the first and second colored layers 25a. , 25b.

  In the present embodiment, for example, the thickness of the first and second colored layers 25a and 25b is 5 μm, and the thickness of the first and second base portions 40a and 40b is also 5 μm. The depth (d1) of the tapered portion 28a is 1 μm.

  Thereby, the taper portion 28a has an effect of suppressing the rolling of the spherical spacer 32 that is driven and arranged in the taper portion 28a by the above-described ink jet method.

  Even if the depth (d1) of the tapered portion 28a is small, it has a certain effect of suppressing the rolling of the spherical spacer 32, and the suppressing effect increases as it becomes deeper. If it has a depth (d1) of about 1 / min, it can be sufficiently suppressed.

(Embodiment 2)
Hereinafter, the tapered portion 28b, which is a characteristic part of the second embodiment of the liquid crystal display device according to the present invention, will be described with reference to FIG. 2 and FIGS. In addition, structures other than the taper part 28a of Embodiment 1 shall be provided similarly also in this Embodiment. The same parts are denoted by the same reference numerals.

  The tapered portion 28b of the second embodiment is different from the first embodiment in that the tapered portion 28b is formed without using the base portion 40, as compared with the tapered portion 28a of the first embodiment.

  FIG. 5 is different from FIG. 3 and shows the relationship between the colored layers 25a, 25b, 25c, the through hole 27, and the tapered portion 28b when the portion indicated by the broken line (R) in FIG. 2 is viewed from the counter substrate 11 side. FIG. 6 is another enlarged plan view of the array substrate 10.

  6 is an enlarged cross-sectional view taken along the line CC of FIG.

  Here, the tapered portion 28b is provided on the third colored layer 25c. The tapered portion 28b is formed by adding light and dark to the photomask and adjusting the exposure amount.

  In the present embodiment, since the base portion 40 is not used, the tapered portion 28b can be formed at a location other than the peripheral portion of the third colored layer 25c or the through hole 27.

  The depth (d2) of the tapered portion 28b can be set to a desired depth by adjusting the exposure amount with the film thickness forming the tapered portion 28b, for example, 5 μm as the upper limit in the case of the third colored layer 25c. .

  As a result, as in the first embodiment, there is an effect of suppressing the rolling of the spherical spacer 32 that is driven and arranged in the tapered portion 28b.

  In the above-described embodiment, each of the colored layers 25a, 25b, and 25c has been described for the lattice structure, but the present invention can be similarly applied to a stripe structure.

  FIG. 7 is an enlarged plan view of the array substrate 10 showing the relationship between the colored layers 25a, 25b, 25c and the spherical spacer 32, to which the present embodiment is applied to a liquid crystal display device having a stripe structure.

  FIG. 8 is an enlarged cross-sectional view taken along the line DD of FIG.

  Even when each of the colored layers 25a, 25b, and 25c is formed in a stripe structure, the tapered portion 28c can be formed by adding light and shade to the photomask and adjusting the exposure amount. It produces the same effect as the structure.

  In addition, this invention is not limited to the above structure, A various deformation | transformation is possible.

The perspective view which shows the liquid crystal display device by this invention. The expanded sectional view cut | disconnected along the AA line of FIG. FIG. 3 is an enlarged plan view of the array substrate according to the first embodiment, showing a broken line (R) portion in FIG. 2. The expanded sectional view which follows the BB line of FIG. FIG. 9 is another view showing a broken line portion (R) portion of FIG. 2, and is an enlarged plan view of the array substrate of the second embodiment. The expanded sectional view which follows the CC line of FIG. FIG. 4 is an enlarged plan view of an array substrate in a stripe structure according to the second embodiment. The expanded sectional view which follows the DD line | wire of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Array substrate, 11 ... Counter substrate, 12 ... Display area, 22 ... Signal line, 24 ... Pixel electrode, 25 ... Organic insulating film, 26 ... Thin-film transistor, 27 ... Through-hole, 28a, 28b, 28c ... Tapered part, 30 ... Liquid crystal layer, 32 ... Spherical spacer, 40 ... Base part, 40a ... First base part, 40b ... Second base part.

Claims (2)

A plurality of scanning lines and signal lines provided on the array substrate;
Switching elements provided at intersections of the scanning lines and the signal lines;
An organic insulating film formed on the array substrate so as to cover the scanning lines, the signal lines, and the switching elements, and comprising first, second, and third colored layers colored in different colors by a resist; ,
A pixel electrode formed on the organic insulating film to form a display region;
A through hole provided in the organic insulating film to electrically connect the pixel electrode and the switching element;
A counter substrate disposed to face the array substrate;
A spherical spacer that is disposed between the array substrate and the counter substrate, and holds between the substrates;
A tapered portion which is on the surface of the organic insulating film and is recessed at a predetermined interval in a portion other than the display region;
A liquid crystal display device comprising a liquid crystal layer sandwiched between the array substrate and the counter substrate,
The spherical spacer is dropped into the tapered portion by an ink jet method in which a dispersion liquid containing the spherical spacer is integrally discharged while moving the nozzle at a predetermined interval with respect to the array substrate, and the tapered portion is a roll of the spherical spacer. A liquid crystal display device characterized by suppressing the above.   2. The taper portion is formed by applying any one of the first, second, and third colored layers as a base portion and depositing the remaining one layer. A liquid crystal display device according to 1.

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