JP3077364B2 - Active matrix liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix liquid crystal display device.

[0002]

2. Description of the Related Art In an active matrix liquid crystal display device, liquid crystal is sealed between a display driving panel having a display driving element composed of pixel electrodes and thin film transistors and a common electrode panel having a common electrode. In this case, in order to prevent light from leaking from portions other than the pixel portion, a lattice-shaped light-shielding portion called a black mask or the like is provided on the common electrode panel. By the way, when assembling such an active matrix liquid crystal display device, when a common electrode panel is superimposed on a display drive panel via a spacer, a white cross mark is formed at a predetermined diagonal corner of the common electrode panel. And a black cross mark slightly larger than the white cross mark is provided at the corresponding position of the display drive panel, and when both are superimposed, the white cross mark does not protrude from the black cross mark, that is, The alignment is performed so that the light leaked by the air gap cannot be seen.

[0003]

However, when such a conventional alignment method for an active matrix liquid crystal display device is applied to a device having a small pixel pitch, after the alignment, the above-described grid-shaped light-shielding portion and the pixel are removed. When the degree of overlap with the electrodes is examined, as shown by the dotted lines in FIG. 3, the positions where the ends 1a and 1b of each pixel electrode 1 have a predetermined inclination angle with respect to the side edges 2a and 2b of the light shielding portion 2 are shown. Misalignment has occurred. The gap 3 caused by this displacement is an area that does not change in the display state or the non-display state, and therefore should not be present. As described above, the conventional method has a problem that the positioning accuracy between the common electrode panel and the display driving panel cannot be said to be sufficiently high. SUMMARY OF THE INVENTION An object of the present invention is to provide an active matrix liquid crystal display device capable of sufficiently increasing the alignment accuracy between a common electrode panel and a display drive panel.

[0004]

According to the present invention, a liquid crystal is sealed between a display drive panel having a pixel electrode and a display drive element and a common electrode panel having a common electrode, and a liquid crystal is sealed around each of the pixel electrodes. In an active matrix liquid crystal display device in which a grid-shaped light-shielding portion covering a portion is provided on the common electrode panel, a positional shift from the side edge is made corresponding to a side edge of the light-shielding portion of the common electrode panel. An alignment mark for visual recognition is provided on the display drive panel.

[0005]

According to the present invention, the misalignment between the grid-like light-shielding portion and the pixel electrode can be directly visually recognized by the alignment marks provided corresponding to the side edges of the light-shielding portion. The alignment accuracy with the display drive panel can be made sufficiently high.

[0006]

FIG. 1 shows a main part of an active matrix liquid crystal display device according to an embodiment of the present invention. This active matrix liquid crystal display device has a structure in which a common electrode panel 31 is superimposed on a display drive panel 11 via a spacer (not shown), and a liquid crystal 41 is sealed therebetween.

First, the common electrode panel 31 will be described. The common electrode panel 31 includes a glass substrate 32. On the lower surface of the glass substrate 32, in order to regulate the size of the display pixel portion and to prevent light leakage from the portion other than the pixel portion, a lattice-like portion made of chrome, aluminum, or the like corresponding to portions other than the pixel portion is provided. A light-shielding portion 33 is provided (see FIG. 2). A color filter 34 is provided on the lower surface of the glass substrate 32 in a part other than the light shielding part 33, and as shown in FIG. 2, the part of each color filter 34 surrounded by the side edges 33a and 33b of the light shielding part 33 has a square shape. Pixel section 35. A transparent resin layer 36 is provided on the entire lower surface of the light shielding portion 33 and the color filter 34. A common electrode 37 made of ITO is provided on the lower surface of the resin layer 36.
Are patterned. An alignment film 38 is provided on the entire lower surface of the resin layer 36 including the common electrode 37.

Next, the display drive panel 11 will be described. The display drive panel 11 has a glass substrate 12. At a predetermined location on the upper surface of the glass substrate 12, a semiconductor thin film 14 made of amorphous silicon or polysilicon and constituting a part of a thin film transistor (display driving element) 13 is pattern-formed. The central portion of the semiconductor thin film 14 is a channel region 14a, and the left and right sides thereof are a drain region 14b and a source region 14c. On the upper surface of the channel region 14a of the semiconductor thin film 14, a gate electrode 16 made of chromium, aluminum, or the like is pattern-formed via a gate insulating film 15 made of silicon oxide. Gate electrode 16 is covered with interlayer insulating film 17. Drain region 14b of semiconductor thin film 14
An underlying layer 18 made of silicon oxide is provided on the entire upper surface of the glass substrate 12 including the source region 14c. Contact holes 19 and 20 are formed in the underlayer 18 at portions corresponding to the drain region 14b and the source region 14c of the semiconductor thin film 14, and chromium is formed at predetermined positions on the contact holes 19 and 20 and the upper surface of the underlayer 18. A drain electrode 21 and a source electrode 22 made of aluminum or aluminum are patterned.

At a predetermined location on the upper surface of the underlayer 18 in the vicinity of the thin film transistor 13, after the gate insulating film 15 is formed and before the gate electrode 16 is formed, the IT
A square pixel electrode 23 made of O is patterned (see FIG. 2). As shown in FIG. 2, the size of the pixel electrode 23 is slightly larger than the size of the rectangular pixel portion 35 between the light shielding portions 33 of the common electrode panel 31. A rectangular pixel portion 35 between the light shielding portions 33 of the common electrode panel 31
At the two predetermined positions on the upper surface of the pixel electrode 23 corresponding to the portions immediately inside the two corners on the predetermined one diagonal line, the same material, that is, chromium, aluminum, or the like, is used at the same time when the gate electrode 16 is formed. Square alignment mark 24
Are formed (see FIG. 2). Alignment mark 24
Are formed on all the pixel electrodes 23 so as not to protrude outward from the pixel electrodes 23. Note that the source electrode 22 of the thin film transistor 13 is connected to the pixel electrode 23, and as shown in FIG. 2, the gate electrode 15 is connected to the gate line (scanning electrode) 25, and the drain electrode 21 is connected to the drain line (signal electrode) 26. It is connected to the. Thin film transistor 13, pixel electrode 23, alignment mark 24
In addition, a passivation film 27 made of silicon oxide, silicon nitride, or the like is provided on the entire upper surface of base layer 18. An alignment film 28 is provided on the entire upper surface of the passivation film 27.

When the common electrode panel 31 is superimposed on the display drive panel 11 via a spacer in assembling the active matrix liquid crystal display device, as shown in FIG. It overlaps with each intersection of the side edge parts 33a and 33b of the part 33. Since the alignment mark 24 is formed on each pixel electrode 23 so as not to protrude from the pixel electrode 23, each pixel portion 3 can be used as long as this alignment is performed.
No portion of 5 protrudes from each pixel electrode 23, that is, a gap due to misalignment does not occur. Therefore, the common electrode panel 31
And the display drive panel 11 can have sufficiently high positioning accuracy.

It should be noted that the alignment marks 24 need not be formed corresponding to all the pixel portions 35, but may be provided only at required positions. Further, the alignment mark 24 does not need to be provided at a corner of the pixel portion 35, and may be provided at a position where the alignment with the side edges 33a and 33b of the light shielding portion 33 can be visually recognized.

[0012]

As described above, according to the present invention, the misalignment between the lattice-shaped light-shielding portion and the pixel electrode is directly controlled by the alignment marks provided corresponding to the side edges of the light-shielding portion. Since it is visible, the alignment accuracy between the common electrode panel and the display drive panel can be sufficiently increased.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of an active matrix liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a plan view of the active matrix liquid crystal display device.

FIG. 3 is a plan view illustrating a problem of a conventional active matrix liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Display drive panel 13 Thin film transistor (display drive element) 23 Pixel electrode 24 Alignment mark 31 Common electrode panel 33 Shielding part 33a, 33b Side edge part 35 Pixel part 37 Common electrode 41 Liquid crystal

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1368 G02F 1/1335

Claims (3)

(57) [Claims] 1. A grid-like light-shielding portion in which liquid crystal is sealed between a display drive panel having a pixel electrode and a display drive element and a common electrode panel having a common electrode, and a peripheral portion of each pixel electrode is covered. In the active matrix liquid crystal display device provided on the common electrode panel, an alignment mark for visually recognizing a displacement from the side edge corresponding to a side edge of the light shielding portion of the common electrode panel. An active matrix liquid crystal display device provided on the display drive panel. 2. The active matrix liquid crystal display device according to claim 1, wherein said alignment mark is formed on said pixel electrode. 3. The active matrix liquid crystal display device according to claim 1, wherein said alignment mark is made of the same material as at least one electrode of said display drive element.