JP2017191155A - Display device - Google Patents

Abstract

A direct current may be applied to a liquid crystal cell, and at this time, charges are accumulated in an alignment film. A display device includes an array substrate and a counter substrate. The array substrate includes a video signal line, a scanning signal line, a common electrode, a pixel electrode, an insulating film disposed between the common electrode and the pixel electrode, and a protrusion formed on the insulating film, An electrode formed on the protrusion, and an alignment film formed on the pixel electrode, the insulating film, and the electrode. A potential different from that of the pixel electrode is supplied to the electrode. [Selection] Figure 1

Description

  The present disclosure relates to a display device, and can be applied to, for example, a liquid crystal display device including a charge removing unit.

  In the liquid crystal display, when the DC driving is performed, the life is shortened. Therefore, the AC voltage driving is performed by applying the AC voltage. The drive voltage by alternating current must be applied so that both positive and negative voltages are equal.

JP 2004-302448 A

When an alternating voltage is applied to the liquid crystal cell, a direct current is applied to the liquid crystal cell due to the effect of misalignment of the punch electrode. At this time, charges are accumulated in the alignment film, and the alternating voltage applied to the liquid crystal layer becomes asymmetric between the positive electrode and the negative electrode, causing flicker.
An object of the present disclosure is to provide a display device that reduces charges accumulated in an alignment film.
Other problems and novel features will become apparent from the description of the present disclosure and the accompanying drawings.

The outline of a representative one of the present disclosure will be briefly described as follows.
That is, the display device includes an array substrate and a counter substrate. The array substrate is formed on the insulating film and a video signal line, a scanning signal line, a common electrode, a pixel electrode, an insulating film disposed between the common electrode and the pixel electrode. A protrusion, an electrode formed on the protrusion, and an alignment film formed on the pixel electrode, the insulating film, and the electrode. The electrode is supplied with a potential different from that of the pixel electrode.

Sectional drawing of the array substrate of the display apparatus which concerns on embodiment Plan view of FIG. The top view for demonstrating the whole structure of the display apparatus of Example 1. FIG. Pixel equivalent circuit diagram FIG. 6 is a plan view illustrating a configuration of a part of the display device according to the first embodiment. Sectional drawing in the A-A 'line of FIG. FIG. 6 is a plan view illustrating a configuration of a part of the display device according to the second embodiment. Sectional drawing in the A-A 'line of FIG. Sectional drawing which shows the 1st process of the manufacturing method of the array substrate of the display apparatus which concerns on Example 2. FIG. Sectional drawing which shows the 2nd process of the manufacturing method of the array substrate of the display apparatus which concerns on Example 2. FIG. Sectional drawing which shows the 3rd process of the manufacturing method of the array substrate of the display apparatus which concerns on Example 2. FIG. Sectional drawing which shows the 4th process of the manufacturing method of the array substrate of the display apparatus which concerns on Example 2. FIG. FIG. 6 is a plan view showing a configuration of a part of an array substrate of a display device according to a third embodiment. Sectional drawing in the A-A 'line of FIG.

  Embodiments, examples, and modifications will be described below with reference to the drawings. It should be noted that the disclosure is merely an example, and those skilled in the art can easily conceive of appropriate modifications while maintaining the gist of the invention are naturally included in the scope of the present invention. In addition, the drawings may be schematically represented with respect to the width, thickness, shape, and the like of each part in comparison with actual aspects for the sake of clarity of explanation, but are merely examples, and the interpretation of the present invention is not limited. It is not limited. In addition, in the present specification and each drawing, elements similar to those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description may be omitted as appropriate.

  The array substrate of the display device according to the embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view of an array substrate of a display device according to an embodiment. FIG. 2 is a plan view of FIG. Hereinafter, the + Z direction is referred to as “up” and the −Z direction is referred to as “down”.

  The array substrate 10 according to the embodiment includes an insulating film 11 disposed on the video signal line DL, a scanning signal line GL (not illustrated in FIG. 1) disposed on the insulating film 11, and the scanning signal line GL. An organic film 12 disposed on the organic film 12, a common electrode CT disposed on the organic film 12, an insulating film 13 disposed on the common electrode CT, and a pixel electrode disposed on the insulating film 13 PX. The array substrate 10 further includes a charge removing portion 16 including a protrusion 14 disposed on the insulating film 13 and an electrode 15 disposed on the protrusion 14, the insulating film 13, and the pixel electrode PX. And an alignment film 17 disposed on the charge removal unit 16. The protrusion 14 has a height higher than H from the insulating film 13, and a potential different from that of the pixel electrode PX is supplied to the electrode 15 disposed thereon.

  Since different potentials are supplied to the electrode 15 of the charge removal unit 16 and the pixel electrode PX, the charge accumulated on the alignment film 17 moves due to diffusion and potential gradient. Thereby, flicker can be reduced. If the electrode 15 and the pixel electrode PX have the same potential, the charge stays because there is no escape route for the charge accumulated in the alignment film 17.

  As shown in FIG. 2, the charge removing unit 16 is on the video signal line DL (A region) or on the scanning signal line GL (B region), at the intersection (C region) of the video signal line DL and the scanning signal line GL. However, although it may be anywhere, it is preferable to arrange in the area where the light shielding layer of the display area AR is arranged. The number does not have to be one per pixel, and a plurality of pixels may be provided in the display area AR plane.

  In the display device according to the embodiment, a structure for removing the accumulated electric charge is provided in the cell. By providing an electrode directly under the alignment film, it becomes a passage for electric charge. In addition, the thickness of the alignment film is reduced to reduce the resistance value in order to facilitate the removal of charges. For this reason, the electrode of the charge removal unit exists at a position higher than the pixel electrode located in the opening of the light shielding layer.

  FIG. 3 is a plan view for explaining the overall configuration of the display device according to the first embodiment. FIG. 4 is an equivalent circuit diagram of the pixel. The display device 1A according to the first embodiment includes an array substrate 10A on which the pixel electrodes PX, the thin film transistors TFT, and the like are formed, and a counter substrate 20A on which the color layer (for example, a color filter) 22 is formed. And a liquid crystal layer 30 sandwiched between the array substrate 10A and the counter substrate 20A, and a backlight unit (backlight device) (not shown) serving as a light source. The array substrate 10A and the counter substrate 20A are fixed and the liquid crystal is sealed with a sealing material SL applied in an annular manner to the frame region FR around the counter substrate 20A, and the liquid crystal is also sealed. Yes. However, in the display device 1, a region where display pixels (hereinafter abbreviated as pixels) are formed in the region in which liquid crystal is sealed becomes the display region AR. Therefore, even in the region where the liquid crystal is sealed, a region where pixels are not formed and which is not involved in display is not the display region AR.

  Further, the counter substrate 20A has a smaller area than the array substrate 10A, and the lower side of the array substrate 10A in the figure is exposed. A drive circuit DR composed of a semiconductor chip is mounted on the side of the array substrate 10A. The drive circuit DR drives each pixel arranged in the display area AR. Further, as the array substrate 10A and the counter substrate 20A, for example, a well-known glass substrate is generally used as a base material, but may be a resinous transparent insulating substrate.

  In the display device 1A, the surface of the array substrate 10 on the liquid crystal side and in the display area AR is extended in the X direction in FIG. 3 and arranged in parallel in the Y direction, and a scanning signal is supplied from the drive circuit DR. A scanning signal line (gate line) GL is formed. Further, a video signal line (drain line) DL is formed which extends in the Y direction in FIG. 3 and is juxtaposed in the X direction to which a video signal (gradation signal) from the drive circuit DR is supplied. A region surrounded by two adjacent drain lines DL and two adjacent gate lines GL constitutes a pixel, and a plurality of pixels are matrixed in the display region AR along the drain line DL and the gate line GL. Arranged in a shape.

  For example, as shown in FIG. 4, each pixel is supplied with a thin film transistor TFT that is turned on / off by a scanning signal from the gate line GL and a video signal from the drain line DL through the turned on thin film transistor TFT. A wall-like pixel electrode PX and a wall-like common electrode CT to which a common signal having a reference potential with respect to the potential of the video signal is supplied via the common line CL. In FIG. 4, the pixel electrode PX and the common electrode CT are schematically illustrated in a linear shape, but the configuration of the pixel electrode PX and the common electrode CT will be described in detail later. Note that the thin film transistor TFT is driven so that the drain electrode and the source electrode are switched by application of the bias. However, for the sake of convenience, the side connected to the drain line DL is referred to as the drain electrode and the wall pixel electrode PX. The connected side is referred to as a source electrode.

  Each drain line DL and each gate line GL extend beyond the sealing material SL at their ends, and based on an input signal input from an external system through the flexible printed circuit board FPC, a video signal, a scanning signal, etc. Is connected to a drive circuit DR that generates a drive signal. However, in the display device 1, the drive circuit DR in which the scan signal drive circuit for generating the drive signal for the scan line is formed of a semiconductor chip is mounted on the array substrate 10. A configuration in which the region is formed of a TFT or the like may be used.

  The first embodiment is an example in which the charge removing unit is disposed on the video signal line (A region), and this will be described with reference to FIGS. FIG. 5 is a plan view illustrating the configuration of the display device according to the first embodiment. 6 is a cross-sectional view taken along the line A-A 'of FIG.

  The array substrate 10A is disposed on a video signal line DL disposed on a glass substrate (not shown), an insulating film 11 disposed on the video signal line DL, and the insulating film 11, FIG. A scanning signal line GL (not shown), an organic film 12 disposed on the scanning signal line GL, a common electrode CT disposed on the organic film 12, and an insulating film 13 disposed on the common electrode CT And a pixel electrode PX disposed on the insulating film 13. The array substrate 10A further includes a charge removal unit 16A including a protrusion 14A disposed on the insulating film 13 above the video signal line DL and an electrode 15A disposed on the protrusion 14A. And an alignment film 17 disposed on the insulating film 13, the pixel electrode PX, and the charge removing portion 16A. The protruding portion 14A has a height equal to or higher than H from the insulating film 13, and a potential different from that of the pixel electrode PX is supplied to the electrode 15A disposed thereon. For example, when the height of the protrusion 14A is 0.5 μm or more (H ≧ 0.5 μm), the thickness of the alignment film 17 is 50 nm or less. By reducing the thickness of the alignment film 17 on the electrode 15, the resistance of the alignment film 17 is reduced, and the accumulated charges are easily removed from the electrode 15 </ b> A. For example, the electrode 15A is connected to the common electrode CT as in Example 2 described later.

  The counter substrate 20A includes a light shielding layer 21 disposed under a glass substrate (not shown), a color layer 22 disposed in an opening of the light shielding layer 21, and an overlayer disposed under the light shielding layer 21 and the color layer 22. A coat layer 23 and an alignment film 24 disposed under the overcoat layer 23 are provided. The alignment film 17 on the projection 14A of the array substrate 10A and the alignment film 24 on the counter substrate 20A side may or may not contact each other. The counter substrate 20A may be provided with a protrusion similar to the protrusion 25 described later in the second embodiment.

  The second embodiment is an example in which a charge removing unit is disposed on an intersection between a video signal line and a scanning signal line. This will be described with reference to FIGS. FIG. 7 is a plan view illustrating the configuration of the display device according to the second embodiment. FIG. 8 is a cross-sectional view taken along line A-A ′ of FIG. 7.

  The array substrate 10B of the display device 1B according to the second embodiment has the same structure as the array substrate 10A according to the first embodiment, except for the position and shape of the charge removal unit. The counter substrate 20B according to the second embodiment has the same structure as the counter substrate 20A according to the first embodiment.

  The array substrate 10B includes a video signal line DL disposed on a glass substrate (not shown), an insulating film 11 disposed on the video signal line DL, and a scanning signal line GL disposed on the insulating film 11. The organic film 12 disposed on the scanning signal line GL, the common electrode CT disposed on the organic film 12, the insulating film 13 disposed on the common electrode CT, and the insulating film 13 A pixel electrode PX to be disposed. The array substrate 10B further includes a projection 14B disposed on the insulating film 13 and an electrode 15B disposed on the projection 14B at the intersection of the video signal line DL and the scanning signal line GL. The charge removal unit 16B is provided, and the alignment film 17 is disposed on the insulating film 13, the pixel electrode PX, and the charge removal unit 16B. The electrode 15B is connected to the common electrode CT and supplied with a potential different from that of the pixel electrode PX. The height of the protrusion 14B is the same as that of the protrusion 14A of the first embodiment.

  The alignment film 17 on the protrusion 14B of the array substrate 10B and the alignment film 24 on the counter substrate 20 may be in contact with each other, or may not be in contact. Further, when the alignment film 17 on the protrusion 14B of the array substrate 10B is in contact with the alignment film 24 on the counter substrate 20B side, the protrusion 25 is provided on the counter substrate 20B side and is in contact with the alignment film 24 below the protrusion 25. You may do it.

  A manufacturing method for connecting the electrode of the array substrate 10B and the common electrode will be described with reference to FIGS. FIG. 9 is a cross-sectional view illustrating a first step of the method of manufacturing the array substrate of the display device according to the second embodiment. FIG. 10 is a cross-sectional view illustrating a second step of the method for manufacturing the array substrate of the display device according to the second embodiment. FIG. 11 is a cross-sectional view illustrating a third step of the method of manufacturing the array substrate of the display device according to the second embodiment. FIG. 12 is a cross-sectional view illustrating a fourth step of the method for manufacturing the array substrate of the display device according to the second embodiment.

  First, a metal film is formed on a glass substrate (not shown) to form a video signal line DL, an insulating film 11 is formed on the video signal line DL, and a metal film is formed on the insulating film 11 and scanned. The signal line GL is formed, the organic film 12 is formed on the scanning signal line GL, the ITO is formed on the organic film 12 to form the common electrode CT, and the insulating film 13 is formed on the common electrode CT. Form.

  Next, as shown in FIG. 9, in the first step, for example, an organic film is formed on the insulating film 13 to form a protrusion 14B, and then a hole is formed in the insulating film 13 so as to expose the common electrode CT. To form contact holes CNT.

  Next, as shown in FIG. 10, after the first step, in the second step, ITO is formed on the entire surface, and a resist film is applied on the formed ITO.

  Next, as shown in FIG. 11, after the second step, in the third step, the resist is patterned using a photomask.

  Next, as shown in FIG. 12, after the third step, in the fourth step, the remaining resist is etched using the mask, and the resist is removed to form the electrode 15B connected to the common electrode CT. At this time, the pixel electrode PX may be formed simultaneously.

  The third embodiment is an example in which a protrusion is disposed on an intersection between a video signal line and a scanning signal line, and an electrode is extended on the scanning signal line to form a charge removal unit. FIG. 14 will be described. FIG. 13 is a plan view illustrating the configuration of the array substrate of the display device according to the third embodiment. FIG. 14 is a cross-sectional view taken along the line A-A ′ of FIG. 13.

  The array substrate 10C of the display device according to the third embodiment has the same structure as the array substrate 10 of the first embodiment except that the position of the charge removal unit and the electrode are not connected to the common electrode. The counter substrate according to the third embodiment has the same structure as the counter substrate 20A of the first embodiment.

  The array substrate 10C includes a video signal line DL disposed on a glass substrate (not shown), an insulating film 11 disposed on the video signal line DL, and a scanning signal line GL disposed on the insulating film 11. The organic film 12 disposed on the scanning signal line GL, the common electrode CT disposed on the organic film 12, the insulating film 13 disposed on the common electrode CT, and the insulating film 13 And a pixel electrode PX (not shown in FIG. 14). The array substrate 10C further includes a charge removing portion 16C composed of a protrusion 14C disposed on the insulating film 13 and an electrode 15C disposed on the protrusion 14C, the insulating film 13 and the pixel electrode PX. And an alignment film 17 disposed on the charge removing portion 16C. In the protrusion 14C, a plurality of video signal lines DL and scanning signal lines GL are arranged along the scanning signal lines GL on the intersections. The electrode 15C extends on the scanning signal line GL along the scanning signal line GL, is connected to a wiring (not shown) in the frame region FR outside the display region AR, and is supplied with a potential different from the potential of the pixel electrode. The height of the protrusion 14C is the same as that of the protrusion 14A of the first embodiment.

  The alignment film 17 on the protruding portion 14C of the array substrate 10C may be in contact with the alignment film on the counter substrate 20 side, or may not be in contact. The counter substrate may be provided with a protrusion similar to the protrusion 25 of the second embodiment.

1A, 1B, 1C ... Display devices 10, 10A, 10B, 10C ... Array substrate 11 ... Insulating film 12 ... Organic film 13 ... Insulating films 14, 14B, 14C ... Projections 15, 15B, 15C ... Electrodes 16, 16B, 16C ... Charge removal unit 17 ... Alignment film DL ... Video signal line CL ... Common line CT ... Common electrode PX ... Pixel Electrodes 20A, 20B, 20C ... counter substrate 21 ... light shielding layer 22 ... color layer 23 ... overcoat layer 24 ... alignment film 25 ... projection

Claims (10)

The display device
An array substrate;
A counter substrate;
With
The array substrate is
Video signal lines,
A scanning signal line;
A common electrode;
A pixel electrode;
An insulating film disposed between the common electrode and the pixel electrode;
A protrusion formed on the insulating film;
An electrode formed on the protrusion,
An alignment film formed on the pixel electrode, the insulating film, and the electrode;
With
The electrode is supplied with a potential different from that of the pixel electrode. The display device according to claim 1.
The electrode is connected to the common electrode. The display device according to claim 1.
The electrodes are connected to wirings arranged outside the display area. The display device according to claim 1.
The electrode is disposed on the video signal line. The display device according to claim 1.
The electrode is disposed on the scanning signal line. The display device according to claim 1.
The electrode is disposed on a portion where the video signal line and the scanning signal line intersect. The display device according to claim 1.
The height of the protrusion is 0.5 μm or more. The display device according to claim 1.
The counter substrate is
A light shielding layer;
Color layers,
An overcoat film,
An alignment film;
Is provided. The display device according to claim 8.
The alignment film on the electrode is in contact with the alignment film on the counter substrate. The display device according to claim 8.
The counter substrate further includes a protrusion,
The electrode is in contact with the protrusion through the alignment film.

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