JPH05158068A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display device provided with a light shielding film which attains high numerical aperture and its production as for the liquid crystal display device provided with the light shielding film which attains the high numercial aperture of a picture element and its production. CONSTITUTION:This device is provided with a 1st substrate 10 having a picture element electrode 18, a 2nd substrate 22 having a common electrode 27 arranged to be opposed to the substrate 10 at specified space so as to interpose a liquid crystal layer 29, a thin film transistor element formed on the opposed surface of the substrate 10 to the substrate 22, and the light shielding film 23 formed to cover the thin film transistor element on the thin film transistor element on the substrate 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly to a liquid crystal display device having a light-shielding film that enables a high pixel aperture ratio and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 3 schematically shows an example of a sectional structure of a pixel portion of a conventional liquid crystal display device, and a conventional liquid crystal display device will be described below with reference to it.

A thin film transistor region 31 and a pixel electrode 32 are formed on one glass substrate 30. On the other glass substrate 33, the black matrix 3 also serving as a light-shielding film facing the thin film transistor region 31 and covering it.
4 and a color filter 35, and a common electrode layer 36 is further formed thereon.

Although not shown, both substrates are further subjected to an alignment treatment to assemble a liquid crystal cell with a predetermined space kept between the substrates. Further, a liquid crystal layer 37 is arranged between the substrates to form a liquid crystal display device.

[0005]

The light-shielding film / black matrix 34 formed on the substrate 33 serves as a black matrix for dividing adjacent pixels and the thin film transistor 3 is formed.
The thin film transistor region 3 serves as a light-shielding film that prevents light from entering the first thin film transistor 1. However, in consideration of variations in positioning accuracy of the upper and lower two substrates 30 and 33 (overlapping shift).
Patterning is performed so as to cover an area slightly larger than 1.

Therefore, the light-shielding area tends to be larger than necessary, the aperture ratio of the pixel is reduced, and the brightness of the screen is limited. An object of the present invention is to provide a liquid crystal display device having a light-shielding film that enables a high aperture ratio and a manufacturing method thereof.

[0007]

A liquid crystal display device according to the present invention includes a first substrate having a pixel electrode and a common substrate arranged so as to face the first substrate and sandwich a liquid crystal layer at a predetermined interval. A second substrate having an electrode, a thin film transistor element formed on a surface of the first substrate facing the second substrate, and the thin film transistor element on the thin film transistor element of the first substrate. And a light-shielding film formed as described above.

A method of manufacturing a liquid crystal display device according to the present invention comprises:
Forming a thin film transistor and a pixel electrode on the first substrate; covering a region other than the region of the pixel electrode on the first substrate with a light shielding film; and forming a second substrate having a width narrower than the light shielding film. Forming a black matrix, forming a color filter layer on the second substrate, and forming a common electrode layer on the black matrix and the color filter layer of the second substrate, The first
And the second substrate and the liquid crystal is sealed between them.

[0009]

By forming the light-shielding region on the thin film transistor element of the first substrate, it is not necessary to consider a margin due to misalignment of the first and second substrates when patterning the light-shielding film, and the minimum necessary light-shielding is performed. Since the area is large, the aperture ratio is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal display device according to an embodiment of the present invention will be described below with reference to FIGS. In addition, in FIG.
FIG. 2 shows a sectional structure of a liquid crystal display device in an example of the present invention, and FIG. 2 is a plan view of the structure shown in FIG.

In FIG. 1, a gate electrode 11 made of Cr or the like, a gate insulating layer 12 made of SiO ₂ or the like, an a-Si (amorphous silicon) semiconductor layer 13 forming a channel, and SiNx (silicon nitride) are formed on an alkali-free glass substrate 10. Etching stopper layer 14, n-type (more specifically, n ⁺ -type) Si contact layer 15, and source electrode 1
6, the drain electrode 17 is sequentially formed to form a thin film transistor (TFT) element.

These are formed in the same manner as in the prior art, but for example, the layers can be formed by vapor deposition, sputtering, CVD, etc., and the patterning can be performed by photolithography using a photoresist. Etching stopper layer 14
Protects the a-Si layer 13 from being etched when the source electrode 16, the drain electrode 17, and the contact layer 15 are patterned.

Further, an IT connected to the drain electrode 17
After forming the pixel electrode 18 of O (indium tin oxide) and forming the passivation layer 19 on the TFT,
As shown by the shaded area in the plan view of FIG.
It is formed so as to completely cover the FT and further cover the entire area of the pixel electrode 18 other than the substantial pixel area.

Of course, the extraction electrode (not shown) on the outer periphery of the liquid crystal cell is not covered with the light shielding layer. As the material of the light shielding layer 20, a black film such as dyeing black or pigment dispersion black may be used. Furthermore, an alignment layer 21 is formed on the alignment layer 21.
Is provided.

Next, a black matrix 23 is formed of Cr ₂ O ₃ (chromium oxide) or Cr for dividing the space between adjacent pixels on another alkali-free glass substrate 22 which is arranged to face the substrate 10. The pattern width of the black matrix 23 is made smaller than the width of the light shielding layer 20 of the lower substrate so that the aperture ratio is not reduced.

Next, color filters 24 and 25 are formed by a dyeing method or a pigment dispersion method, and an overcoat layer 26, a common electrode layer 27 made of ITO, and an alignment layer 28 are sequentially laminated on the color filters 24 and 25.

A gap control agent is sprinkled between the two substrates formed as described above, the two substrates are overlapped so that the pixel surface and the color filter are exactly opposite to each other, and the liquid crystal 29 is sealed. Is injected and the liquid crystal injection port is sealed to form a liquid crystal display device.

Although the black matrix is also formed on the side of the substrate having the common electrode, the black matrix may be omitted if the color filters can be separated. TF
Since the light shielding film is formed directly on T, the light shielding effect on the TFT is high. It is not necessary to allow for a margin due to the alignment of the two substrates.

The present invention has been described above with reference to the embodiments.
The present invention is not limited to these. For example,
It will be apparent to those skilled in the art that various modifications, improvements, combinations and the like can be made.

[0020]

EFFECTS OF THE INVENTION By forming the light-shielding region covering the thin-film transistor region on the side of the substrate on which the thin-film transistor is formed, it is not necessary to allow a margin due to misalignment of the upper and lower substrates when patterning the light-shielding film, and the necessary minimum Since it requires only a light-shielding area, the aperture ratio is improved.

Further, since light can be shielded just above the thin film transistor, there is almost no photodegradation due to stray light from the diagonal side.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a liquid crystal display device according to the present invention.

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

FIG. 3 is a diagram illustrating a cross-sectional structure of a conventional liquid crystal cell.

[Explanation of symbols]

10: Alkali-free glass substrate 11: Gate electrode 12: Gate insulating layer 13: a-Si semiconductor layer 14: Etching Stopper layer 15: n-type (n ⁺ type) semiconductor layer 16: source electrode 17: drain electrode 18: pixel electrode 19: ··· Passivation layer 20 ··· Light-shielding layer 21 ··· Alignment layer 22 ··· Alkali-free glass substrate 23 ··· Black matrix 23 24, 25 · · · Color Filter 26 ・ ・ ・ ・ Overcoat layer 27 ・ ・ ・ ・ ・ Common electrode layer 28 ・ ・ ・ ・ Alignment layer 29 ・ ・ ・ ・ Liquid crystal layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 29/784

Claims (4)

[Claims] 1. A first substrate having a pixel electrode; a second substrate having a common electrode facing the first substrate so as to sandwich a liquid crystal layer at a predetermined interval; A thin film transistor element formed on a surface of the substrate facing the second substrate, and a light shielding film formed on the thin film transistor element of the first substrate so as to cover the thin film transistor element. Liquid crystal display device. 2. The light-shielding film is formed so as to cover all portions of the surface of the first substrate facing the second substrate other than the pixel electrodes. Item 3. A liquid crystal display device according to item 1. 3. The liquid crystal display device according to claim 1, wherein the light-shielding film includes an insulating organic black layer containing either dyed black or pigment-dispersed black. 4. A step of forming a thin film transistor and a pixel electrode on a first substrate, a step of covering a region other than a region of the pixel electrode of the first substrate with a light shielding film, and a light shielding film on a second substrate. A step of forming a black matrix having a width narrower than that of the second substrate, a step of forming a color filter layer on the second substrate, and a common electrode layer on the black matrix and the color filter layer of the second substrate. A method of manufacturing a liquid crystal display device, comprising: a forming step; and a step of superposing the first substrate and the second substrate and enclosing a liquid crystal therebetween.